moglabs M Series Mini Laser Controller Instruction Manual

The Mini Laser Controller by MOGLabs is designed for use in
scientific research laboratories. It includes various protection
features to ensure safe and effective operation of your laser.

Safety Precautions:

Safe and effective use of this product is crucial. Please read
and follow the safety precautions provided in the user manual
before operating the laser. Some important safety notes
include:

Implement appropriate hazard minimizations like laser safety
goggles, beam blocks, and door interlocks.

Ensure the device chassis has a good ground connection.
Operate the unit with the cover on to maintain correct cooling
airflow.

Avoid operating the unit with the cover removed as it exposes
high voltage components.

Protection Features:

The MOGLabs mLC controller includes the following protection
features:

Softstart: Delays diode current ramp up for safety.
Circuit Shutdown: Powers down unused circuitry to prevent
hazards.

Current Limit: Sets a maximum diode injection current.
Cable Continuity: Disables laser power supplies if
disconnection is detected.

Short Circuit Protection: Disables components in case of short
circuits.
Temperature Control: Disables controller at extreme
temperatures.

Internal Supplies Monitoring: Disables system if power supply
voltage is below threshold.
Protection Relay: Safely shorts laser diode when power is
off.

Emission Indicator:

The controller illuminates an emission warning indicator LED
immediately after switching on the laser. There is a delay of at
least 2 seconds before actual laser emission.

Product Usage Instructions:

To use the MOGLabs Mini Laser Controller, follow these
steps:

Ensure all safety precautions are in place, including wearing
appropriate safety gear.
Connect the laser to the controller following the provided
guidelines and make sure all connections are secure.

Power on the controller and wait for the emission warning
indicator LED to illuminate before proceeding.
Operate the laser within the specified parameters and monitor
for any warnings or errors indicated by the controller.

After use, power off the controller and disconnect the laser
following proper shutdown procedures.

Frequently Asked Questions (FAQ):

Q: Can I use the Mini Laser Controller for medical
applications?

A: The MOGLabs mLC is designed for scientific research
laboratories and should not be used for consumer or medical
applications.

Q: What should I do if I encounter a fault condition while
using the controller?

A: If a fault condition is detected, follow the user manual
instructions for troubleshooting or contact MOGLabs support for
assistance.

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Mini Laser Controller
mLC/mCC/mTC
Revision 1.03c

Limitation of Liability
MOG Laboratories Pty Ltd (MOGLabs) does not assume any liability arising out of the use of the information contained within this manual. This document may contain or reference information and products protected by copyrights or patents and does not convey any license under the patent rights of MOGLabs, nor the rights of others. MOGLabs will not be liable for any defect in hardware or software or loss or inadequacy of data of any kind, or for any direct, indirect, incidental, or consequential damages in connections with or arising out of the performance or use of any of its products. The foregoing limitation of liability shall be equally applicable to any service provided by MOGLabs.

Copyright
Copyright © MOG Laboratories Pty Ltd (MOGLabs) 2025 2025. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior written permission of MOGLabs.

Contact

For further information, please contact:

MOG Laboratories P/L 49 University St Carlton VIC 3053 AUSTRALIA +61 3 9939 0677 info@moglabs.com

MOGLabs USA LLC 419 14th St Huntingdon PA 16652 USA +1 814 251 4363 www.moglabs.com

Preface
The MOGLabs mLC Mini Laser Controller provides fully digital control of ECDL or DFB/DBR lasers in an ultra-miniature form factor. The board includes a temperature controller and current source with low noise, high current (up to 1 A), andhigh compliance (up to 8.5 V). It includes a high voltage (180 V) piezo driver as well as a fast ADC input. In addition to two analogue inputs for direct modulation of both piezo and current drivers, the mLC provides an internal lock-in amplifier for AC locking to an atomic transition or high finesse optical cavity. Electrical power input is through a USB-C connection, and the device is compatible with most USB-C power delivery adapters. It can be operated using a computer communications interface (TCP/IP or USB) with simple text-based commands. We hope that the mLC meets and exceeds your expectations. Please let us know if you have any suggestions for improvement in the mLC or in this document, and check our website from time to time for updated information. MOGLabs www.moglabs.com
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Safety Precautions
Safe and effective use of this product is very important. Please read the following safety information before attempting to operate a laser using the MOGLabs mLC controller. Also please note several specific and unusual cautionary notes before use, in addition to the safety precautions that are standard for any electronic equipment or for laser-related instrumentation.
CAUTION USE OF CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF PROCEDURES OTHER THAN THOSE
SPECIFIED HEREIN MAY RESULT IN HAZARDOUS RADIATION OR HIGH VOLTAGE EXPOSURE
Laser output can be dangerous. Please ensure that you implement the appropriate hazard minimisations for your environment, such as laser safety goggles, beam blocks, and door interlocks. MOGLabs takes no responsibility for safe configuration and use of your laser. Please:
· Avoid direct exposure to the beam.
· Avoid looking directly into the beam.
· Note the safety labels and heed their warnings.
· When the laser is switched on, there will be a short delay of three seconds before the emission of laser radiation, mandated by European laser safety regulations (IEC 60825-1).
· A STANDBY/RUN keyswitch must connected, and turned to RUN before the laser can be switched on. The laser will not operate
iii

iv
if the keyswitch is missing or in the STANDBY position. The key cannot be removed when it is in the RUN position.
· To completely shut off power to the unit, turn the keyswitch to STANDBY position, unplug the USB-C cable from the device and/or unplug the USB-C power adapter from the mains.
· When the STANDBY/RUN keyswitch is on STANDBY, there cannot be power to the laser diode, but power can still be supplied to the laser temperature controller and piezo driver.
CAUTION The device chassis must have a good ground connection.
CAUTION To ensure correct cooling airflow, the unit should not be operated with cover removed.
WARNING The internal circuit boards and many of the mounted components are at high voltage, with exposed conductors, in particular various sections of the HV power supply and piezo driver. The unit should not be operated with cover removed.
NOTE The MOGLabs mLC is designed for use in scientific research laboratories. It should not be used for consumer or medical applications.

Protection Features
The MOGLabs mLC includes a number of features to protect you and your laser.
Softstart A time delay (3 s) followed by linear ramp of the diode current (1 s/A).
Circuit shutdown Many areas of the circuitry are powered down when not in use. The diode current supplies may be without power when the unit is in standby mode, if an interlock is open, or a fault condition is detected.
Current limit Sets a maximum possible diode injection current, for all operating modes.
Cable continuity If the laser is disconnected, the system will switch to standby and disable all laser power supplies. If the laser diode, TEC or temperature sensor fail and become open-circuit, they will be disabled accordingly.
Short circuit If the laser diode, TEC or temperature sensor fail and become short-circuit, or if the TEC polarity is reversed, they will be disabled accordingly.
Temperature If the detected temperature is below -5C or above the set limit, the temperature controller is disabled.
Internal supplies If the external USB-CDC power supply (+15 V) is 0.5 V or more below its nominal value, the system is disabled.
Protection relay When the power is off, or if the laser is off, the laser diode is shorted via a normally-opened MOS FET.
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vi
Emission indicator The MOGLabs mLC controller will illuminate the emission warning indicator LED immediately when the laser is switched on. There will then be a delay of at least 2 seconds before actual laser emission.
Key-operated The laser cannot be powered unless the key-operated STANDBY switch is in the RUN position, to enable protection against unauthorised or accidental use. The key cannot be removed from the controller when it is in the clockwise (RUN) position.
Interlocks The mLC controller has an external interlock to allow disabling of the laser via a remote switch, or a switch on the laser cover.

Extending laser diode and piezo lifetime
At night, switch to standby: 1. Switch the laser diode current and piezo driver off. Don’t adjust the current, just press the on/off switch in the mLC control program to power off the diode and/or piezo driver. 2. Switch from RUN to STANDBY.
The temperature controller will continue to operate so that the laser is ready for quick startup the next day, but the laser diode current and piezo voltage will be zero, extending their operating life. In the morning, switch back on:
1. Switch from STANDBY to RUN. 2. Switch the laser diode and/or piezo driver ON by pressing the
on/off switch in the mLC control program. You don’t need to adjust the current or piezo voltage, just wait a few minutes for the diode temperature to equilibrate.
You should switch your MOGLabs mLC into STANDBY mode at nights and weekends and whenever the laser is not being used for more than a few hours. Most lasers need to operate only 40 hours during a 168 hour week; thus switching to standby mode can extend the diode and piezo lifetime by a factor of four.
vii

Contents

Preface

Safety Precautions

iii

Protection Features

Extending laser diode & piezo lifetime

vii

1 Quick start

1.1 On-board connections . . . . . . . . . . . . . . . . . . 1

1.2 Front panel connections . . . . . . . . . . . . . . . . . 3

1.3 Powering up . . . . . . . . . . . . . . . . . . . . . . . . 4

1.4 Remote operation . . . . . . . . . . . . . . . . . . . . . 5

2 MOGMLC computer software

2.1 Device discovery . . . . . . . . . . . . . . . . . . . . . 7

2.2 Main window . . . . . . . . . . . . . . . . . . . . . . . 7

2.3 Main features . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Logging . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.5 Settings . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.6 Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.7 Spectrum analysis . . . . . . . . . . . . . . . . . . . . 14

2.8 Firmware update . . . . . . . . . . . . . . . . . . . . . 16

A Specifications

B Command language

B.1 Arguments . . . . . . . . . . . . . . . . . . . . . . . . . 23

B.2 System overview . . . . . . . . . . . . . . . . . . . . . 24

B.3 ADC and SMA input . . . . . . . . . . . . . . . . . . . 24

B.4 Temperature controller . . . . . . . . . . . . . . . . . . 26

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Contents

B.5 Piezo controller . . . . . . . . . . . . . . . . . . . . . . 28 B.6 Laser diode controller . . . . . . . . . . . . . . . . . . 31 B.7 Ethernet configuration . . . . . . . . . . . . . . . . . . 32

C Communications

C.1 Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 35

C.2 TCP/IP . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

C.3 USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

D Connector pinouts

D.1 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

D.2 Interlock/key . . . . . . . . . . . . . . . . . . . . . . . . 39

D.3 SMA signal input . . . . . . . . . . . . . . . . . . . . . 39

E Troubleshooting

E.1 State flags . . . . . . . . . . . . . . . . . . . . . . . . . 41

E.2 Scanning waveforms . . . . . . . . . . . . . . . . . . . 43

Contents

1. Quick start

The MOGLabs mLC can be used in various configurations, including simple current/temperature controller, passive laser frequency controller with internal or external sweep/scan, resonant cavity controller, and as a complete system for active frequency stabilisation (laser or resonant cavity) with AC, DC or external locking signal.

1.1 On-board connections
In the simplest configuration, the MOGLabs mLC will be used to control the diode injection current and laser temperature. The board has multiple connectors on both top and bottom sides (fig. 1.1). DFB/DBR lasers in a standard 14-pin butterfly package can be directly soldered onto the board. The board must be mounted on a heatsink to prevent potential overheating.

AUX MULT AUX IMOD EXP/TEST
AUX ADC IN PD Power

Auxiliary multifunctional input (UFL connector). Alternative connector for MULT IN.
Auxiliary current modulation input (UFL connector). This connector provides a direct access to the high speed current modulation circuit bypassing the AUX MULT multiplexing circuitry.
Expansion input/output (Hirose BK13 connector). Duplicates LD/TEC/PZT I/O and the input power lines required for expansion boards or internal device testing, and a standard 3.3 V USART interface for communication with the mLC board.
Auxiliary ADC input (UFL connector). Low bandwidth (-3 DB15 3 kHz) ADC input to be used with slowly changing signals. The input voltage should be from 0 to 5 V.
Photodetector power (±12 V). Standard 1.27 mm pitch header. This

2
DBR/DFB Laser

LASR

THERM LED TEC PZT

Chapter 1. Quick start

AUX ADC IN
THERM LED TEC PZT LASR DFB/DBR

PD Power

EXP/TEST
AUX IMOD AUX MULT

Figure 1.1: Top and bottom views of the MOGLabs mLC board.
connector provides power for an external photodetector amplifier board such as the MOGLabs B1131. NTC thermistor input (MOLEX EZmate connector). Indicator LED output (MOLEX EZmate connector). TEC module output (MOLEX EZmate connector). Piezoelectric stack output (MOLEX EZmate connector). Laser diode output (MOLEX EZmate connector). The mLC board can accommodate direct mounting of a standard 14pin butterfly laser package. The laser should be soldered directly to the PCB to ensure a good connection.

1.2 Front panel connections

1.2 Front panel connections
This manual describes the standard mLC with complete front panel (fig. 1.2), which allows operation remotely from a host computer. Other variants of the mLC board may have a different connector set.

PZT MOD

ETH
MULT IN

INTERLOCK/ KEY

USB-C

Figure 1.2: Front view of the MOGLabs mLC board.

USB-C ETH INTERLOCK/KEY
PZT MOD MULT IN

Power input. The USB-C power delivery adapter must be able to provide 15 V, 1 A to power the mLC board.
Twisted pair 10/100 ethernet (RJ45 connector) connection for communication to host computer.
Standard 3.5 mm headphone style connector for both interlock and keyswitch. The pins must be externally short-circuited to enable laser emission. The safety keyswitch must be set to the RUN position to permit laser emission, including for remote operation. Turning to STANDBY will immediately disable power to the laser diode, but the piezo driver and temperature control will continue. Do not supply any voltage to this input; use a relay if necessary.
Piezo driver modulation input (SMA connector). The input provides direct analogue control of the piezo driver. The input voltage should be from 0 to 2.5 V.
Multifunction input (SMA connector). This input can be used for direct laser current modulation (standard ±1 mA) or AC/DC coupled high speed ADC input. The function of this input is set through the mogmlc software. Use this input for a photodetector signal.

Chapter 1. Quick start

1.3 Powering up
1. Ensure all hardware is connected: ethernet, interlock, piezo driver, TEC and laser diode. Do not connect or disconnect the laser while the device is powered on.
2. Connect the USB-C power adapter to the mLC board via a proper USB-C cable that supports USB-C PD; that is, the USB-C power delivery protocol. The USB-C connector is located at the front of the unit.
3. If using ethernet, connect to your local subnet. See appendix C for assistance with configurating the network parameters.
4. Once the booting sequence is complete, the device will appear on the device discoverer in the mogmlc software and the device will now accept connection from a host computer.
5. Set and/or verify both the laser current limit (in the Laser submenu) and the TEC setpoint temperature as necessary to prevent accidentally damaging the laser diode. The maximum safe current is specified in the MOGLabs laser factory test report.
6. Enable the TEC controller and piezo driver. Verify that the measured laser temperature starts converging towards the setpoint temperature.
7. Turn the keyswitch to RUN.
8. Set the laser diode current, initially slightly above the threshold current specified in the laser test report.
9. Activate the laser diode controller. Verify that the laser diode current is ramping and reaches the set value.
10. Control the laser using the host computer interface described below.

1.4 Remote operation

1.4 Remote operation
The mLC is designed for remote operation only, either from the provided standalone WindowsTM application or by integration into custom lab control software using a simple command interface. The command language is defined in appendix B. The mLC app is discussed in detail in the following chapter.

Chapter 1. Quick start

2. MOGMLC computer software
The host software program mogmlc provides a graphical user interface that allows remote control of the mLC controller. mogmlc is available from the MOGLabs website.
It may be necessary to install a firmware update (section 2.8) before being able to use the mogmlc software. If the software detects an incompatibility it will offer to install the update, which can also be obtained from the MOGLabs website.
2.1 Device discovery
Install and start the app, which should then show the device discoverer (see fig. 2.1) which searches for mLC devices accessible over USB or the local network. Use the network interface rather than USB if possible. See chapter C for information on communications.
Select the intended device and click Connect. When multiple mLCs are available, be sure to double-check the name and/or serial number of the device when connecting. If the network does not permit device discovery and/or your mLC does not appear in the list, you can type the IP address in the Device address box, or use USB connection instead.
2.2 Main window
The mLC is designed for remote operation only, either from the provided standalone WindowsTM application or by integration into custom lab control software using a simple command interface. The command language is defined in Section B.
The mLC app (see fig. 2.2) provides control of the laser, and logging of TEC temperature and current, and laser diode current and voltage. An integrated oscilloscope displays the measured photode-
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Chapter 2. MOGMLC computer software

Figure 2.1: MOGLabs device discoverer which shows mLC devices available via USB and network interfaces.
tector voltage and the error signal against piezo scanning position, to assist with adjusting the laser scan parameters and operating the feedback servos and for identifying and locking to features of interest. One full laser sweep is displayed.
2.3 Main features
1. Device identification, the serial number by default but can be assigned by double-clicking. Also shows the current IP address and firmware version.
2. System status indicator, for example whether the laser is active or if a problem has been detected.
3. Primary function controls, permitting enabling or disabling of core functionality such as TEC, piezo, laser diode current and scanning. Click the “gear” button adjacent to each switch for

2.3 Main features
4 6
13 15

9
7 8

1
2
Figure 2.2: MOGLabs mLC WindowsTM application for control and monitoring mLC devices.
additional settings.
4. Laser temperature indicator.
5. Virtual encoders provide a mechanism for smoothly adjusting parameters. Click and drag the dials to adjust the values with fine control, or type a number in the associated box.
6. Tabs for accessing different application functionality, such as logging, oscilloscope or noise spectrum analysis.
7. Drop-down boxes for controlling the input signal and internal lock-in amplifier.
8. Oscilloscope feature, showing the input and demodulated error signals for a complete piezo span.

Chapter 2. MOGMLC computer software

The oscilloscope supports mouse interactions and gestures. Leftclicking and dragging adjusts the input (vertical movement) and piezo (horisontal movement) offsets respectively. Right-clicking adjusts the piezo span.

INPUT+PZT OFFSET

PZT SPAN

PZT SPAN+OFFSET

2.4 Logging

Using the mouse wheel adjusts vertical and horizontal simultaneously to zoom in or zoom out from the position of the mouse cursor.
Double-clicking within the oscilloscope display will toggle whether the laser or cavity is locked. Double-clicking to activate the lock will engage the lock at the mouse position, allowing a transition of interest to be selected.
Bright and dark colour schemes can be accessed via V iew T heme menu.
The mLC software logs the temperature and laser diode current controller operations (see fig. 2.3). The information can be useful for long-term testing of system behaviour and for adjusting locking PID coefficients (see Section 2.5) to improve system stability. Logging graphs can be accessed at any time by clicking on the appropriate tab. The appearance of the logging tab will depend on the hardware variant of the mLC controller. In the default configuration the tab will show the TEC temperature and laser diode current and voltage monitor graphs, but mCC and mTC variants will only show the diode or TEC values.

2.5 Settings
1 2

11
3

2.5 Settings

Figure 2.3: Logging tab shows the temperature convergence of the TEC controller (1) and laser diode current and voltage monitoring (2) graphs respectively. The buttons above (3) can be used to save or clear the data at any time.
Each of the mLC subcomponents (TEC, piezo, laser diode) has additional parameters that can be accessed by clicking the “gear” icon (see fig. 2.4). Usually these parameters do not require a continuous adjustment and only need to be set once. The values are usually preset by MOGLabs manufacturing team during system testing with a dedicated laser or cavity or waveguide doubler but can be further adjusted by the user. The piezo servo controller PID parameters (see fig. 2.5) can be accessed via Device Settings Piezolock menu. In most cases only the integral PID coefficient will require some adjustment. Note that overall servo gain is adjusted through the main window (see fig. 2.2).

Chapter 2. MOGMLC computer software

2.6 Locking

Figure 2.4: Pop-up settings windows be called by clicking the “gear” button at the top right corner of a particular group box (TEC/LD/Piezo).

The mLC can frequency-stabilise the laser using an external error signal, wavemeter, or an internally-generated error signal based on the photodetector input. It is commonly used to lock to an alkali atom, for example with the MOGLabs MGSA saturated absorption reference device. It is also possible to use mLC to lock a resonant doubling cavity to a particular laser frequency to ensure operation on resonance. Below is an outline of how to use the mLC app for laser frequency locking; refer to the relevant laser manual for detailed information about adjusting bias current to achieve a wide modehopfree scan-range.
1. Set the piezo offset to 50%.
2. Adjust diode current to achieve required optical power.

2.6 Locking

Figure 2.5: Piezo servo controller settings window.
3. Make sure that the diode frequency is correct by using a wavemeter or spectrometer.
4. Increase the piezo Span (e.g. to 25%) to see spectral features of interest, adjusting the diode current (Iset) and/or current bias (LD Ibias) to achieve continuous scans without mode-hops.
5. Adjust the piezo offset to ensure the desired locking feature is centred and reduce the piezo Span to zoom in on it.
6. When the piezo span is 2 to 5% activate the piezo dither by selecting the dither checkbox. Dithering can be activated earlier; it will not affect scanning.
7. Increase the MOD amplitude by 0.5 to 1% until the error signal is clean and stable.
8. Adjust Lock phase to optimise error signal for largest negative or positive slope at the locking point.
9. Double-click (with the left mouse button) on the feature you would like to lock to. The unlocked photodetector signal trace (magenta) maintains the last photodetector trace before the piezo is set to the lock point, enabling comparison against the

Chapter 2. MOGMLC computer software

1
12
Figure 2.6: Typical resonant cavity transmission spectra (1) and error signal (2) with optimised phase.
locked photodetector signal (blue). If the DC value does not match the intended setpoint, try inverting the Locking slope polarity and/or decreasing the Lock gain. 10. Increase Lock gain until the error signal amplitude begins to increase, then reduce it by 10%. 11. If required, further optimisation can be achieved using the spectrum analyser mode (FFT tab).
2.7 Spectrum analysis
The mLC application includes a spectral noise analysis tool for optimising the performance of feedback servos. The goal of the servos is to suppress noise in the error signal, which is a measure of the

2.7 Spectrum analysis

laser frequency stability. In general, increasing the gain of the controllers suppresses noise at low frequencies at the expense of increasing noise at high frequencies. Increasing the gain too far will destabilise the controller, which can be detected as a rising peak (known as a “Bode bump”) in the noise spectrum. Figure 2.7

Figure 2.7: The noise spectra for optimal (1) and excessive (2) PID gains respectively.
shows the desired behaviour with the servo activated at the optimal gain, and with excessive gain leading to oscillations at the Bode

Chapter 2. MOGMLC computer software

bump. The frequency of the Bode bump is the servo bandwidth for the combination of frequency discriminator, controller, and control actuator.
Changing the master gain affects the error signal used for the spectrum analysis, and should be kept constant while considering the spectrum. In most cases the integrator gain Ki can be left at the default value; adjusting it is recommended only for advanced users familiar with PID optimisation.

2.8 Firmware update
Firmware updates will be available from the MOGLabs website and should be installed on the device using the mogmlc application.
The firmware update procedure will be activated automatically if the mLC app detects incompatibility (see fig. 2.8). It is recommended to

Figure 2.8: If mogmlc detects a version incompatibility it will offer to install a firmware update.
update firmware using a network connection, but USB can be used. When using USB it may be necessary to unplug the USB cable to reboot the system. The mLC should not be in use while applying a firmware update. The mLC must not be powered off or interrupted during the firmware update or the firmware could become corrupted.
Firmware is distributed as a ZIP file that contains different firmware components. Upon opening the firmware update tool, click the Select button and browse for the firmware ZIP file. The tool will identify the components that need upgrading, which will by installed by clicking the Update all button.

2.8 Firmware update

The firmware update process typically requires the device to reboot several times. A prompt is displayed once the process is complete. Closing the firmware update tool will then allow mogmlc to be used.

Chapter 2. MOGMLC computer software

A. Specifications

Values for parameters marked with an asterisk are calculated from detailed simulations. Experimental verifications are in progress.

Parameter

Specification

Current regulator Output current Noise
Accuracy Max diode voltage Current mod Bandwidth

0 to 1024 mA ±15 µA 1.4 nA/rtHz @ 1 kHz 880 nA rms (1 Hz 1 MHz) ±0.2 ppm/C and 0.1% from setpoint 8 V at 500 mA, 7.5 V at 1024 mA ±25 mA sweep, ±1 mA analogue in 12 MHz (-3 dB) analogue

Temperature Range Stability TEC power Sensor Control
Protection

7.5C to 70C ±0.01C resolution Better than ±10 mK/C ±3 A, ±4.5 V (13.5 W) NTC 10 k PID with variable sample rate Bandwidth 20 Hz TEC over-current, open/short circuit

Piezo Piezo output Sweep/control Resolution Noise Sweep Bandwidth

0 to 180 V, 15 mA (charge and discharge) Direct analogue, and 16-bit digital 2.7 mV at maximum range 790 nV/rtHz @ 1 kHz 1 Hz to 50 Hz Internal 16 kHz; external 100 kHz

Appendix A. Specications

Parameter

Specification

Protection

PCB over-temp

Frequency stabilisation

Bandwidth

10 kHz

Dither

262.5 kHz

Phase

0 – 360

Error signal

16-bit signed, sampling 50 kHz

Post demod filter 4-stage IIR with bypass option

Servo controls

Slow (piezo)

Gain controls

x16/8/4/2/1/0.5/0.25 master

Slow inputs

Slow error (after offset and master gain) Photodetector AC/DC Fast controller out

Slow action

PI or PI2

Signal input/output Signal in Analogue in (2)

2 SMA connectors
Signal range ±4.096 V protected to ±12 V Photodetector
AC/DC: 3.1 MHz > 110 dB dynamic range Piezo mod: analogue direct to piezo Current mod: analogue direct to diode current

Front panel Interlock & Key Communications

3.5 mm headphone jack 3-pin connector TP 10/100 ethernet (RJ-45); USB-C

Connectivity Laser/piezo/TEC

14-pin butterfly PCB footprint 5 MOLEX Pico-Emate connectors 1 Hirose BK13 32-pin connector

Parameter

Specification

Power & dimensions Input Power Dimensions
Weight Operating temp

USB-C power delivery adapter 4 W standby, 30 W peak WxLxH = 56 × 67 × 17.6 mm (board) WxLxH = 125 × 87 × 33 mm (enclosure) 32 g 10 35C

Appendix A. Specications

B. Command language
The mLC can be controlled over USB via a virtual serial port, or over Ethernet using TCP/IP. The syntax follows a text-based request/reply architecture with messages delimited by CRLF. Commands are comma-separated, and respond with a string that begins with either “OK:” or “ERR:” to indicate success or failure. It is strongly recommended that the response is checked before sending a subsequent command.
Please note: The command language is being continuously updated across firmware releases to improve functionality and add features. When upgrading firmware, please refer to the most recent version of the manual available at http://www.moglabs.com
B.1 Arguments
Some commands accept values with units. Units can be specified for values associated with frequency, power, phase and time.
Frequency Hz (default), kHz, MHz Power dBm (default), dB, mW, W Phase deg (default) Time ns, us, ms (default), s Temperature queries report in C; do not use units for setting
Calibrations are used to convert parameters to internal discretised values. Most commands will return a message that includes the actual value, which may differ from the requested value because of discretisation and/or parameter limits.
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Appendix B. Command language

B.2 System overview

INFO

info Report device identification, including running firmware version and serial number. Please include this information in all correspondence with technical support.

DEVNAME

devname Set or query the user-facing name of the mLC. Considered distinct from the user-facing name of the laser.

UPTIME

uptime Query the current uptime of the system, which might be in seconds, minutes or hours as appropriate.

B.3 ADC and SMA input

MLC

mlc Access a list of sub-commands for querying and adjusting the mLC high speed ADC and SMA input.

REPORT mlc,report Report device user-defined name, global flags, mLC board settings register, gain and the offset of the photodetector input. Please refer to section E.1.1 for more information about the global flags.
Use mlc,report,1 to return as a python-compatible dict.

SETTINGS mlc,settings Set or query the mLC settings register.

SMA

mlc,sma Access a list of sub-commands for querying and adjusting the mLC SMA input.

ENABLE mlc,sma,enable Enables the ADC/laser mod SMA input.

DISABLE mlc,sma,disable

B.3 ADC and SMA input

Disables the ADC/laser mod SMA input. When disabled the input is in a high-impedance state.
INPUT mlc,sma,input Connects the SMA port to high speed ADC (AC or DC coupled) input or to laser direct current modulation. Please refer to section D.3 for more information about the options.
HSADC mlc,hsadc Access a list of sub-commands for querying and adjusting the mLC high speed ADC.
ENABLE mlc,hsadc,enable Enables the high speed ADC.
DISABLE mlc,hsadc,disable Disables the high speed ADC, reducing power consumption drops by 300 W.
GAIN mlc,hsadc,gain Set or query the ADC gain setting. The gain is discreet and can be 16, 8, 4, 2, 1, 0.5 or 0.25.
OFFSET mlc,hsadc,offset Set or query the ADC input offset setting. The offset can be -4.096V to 4.096 V.
CAPTURE mlc,hsadc,capture Returns an ADC captured vector. The output is a binary array of 2000 bytes, every two bytes represent a two’s complement signed int16 value giving a total vector length of 1000 points. The time discretisation is equal to pzt,period value divided by 1000.
ERRSIG mlc,hsadc,errsig Returns an error signal vector with format as above.

Appendix B. Command language

B.4 Temperature controller

TEC

tec Access a list of sub-commands for querying and adjusting the mLC temperature controller.

REPORT tec,report Report the state of the TEC controller, flags, VT EC , TT EC , IT EC , current limit, TSET , TMAX , TLIM , PID coefficients KP , KI , KD, enabled/disabled state and TEC polarity. Please refer to section E.1.2 for more information about the TEC flags.
Use tec,report,1 to return as a python-compatible dict.

TSET

tec,tset[,val] Set or query the required set temperature. TSET TLIM. val [-10, 70] in C.

TMAX tec,tmax[,val] Set or query the absolute maximum temperature. val [-10, 70] in C.

TLIM

tec,tlim[,val] Set or query the temperature limit. TLIM TMAX . val [-10, 70] in C.

POLINV tec,polinv[,val] Set or query the TEC polarity inversion. val [0, 1] where 1 is true (invert).

ONOFF tec,onoff[,val] Turns the TEC controller on/off. val [0, 1] where 1 is on. tec,onoff,toggle toggles the controller state.

PID tec,pid Sub-commands for querying and adjusting the TEC PID coefficients.
KP tec,pid,kp

B.4 Temperature controller

Set or query the TEC PID proportional coefficient. kp [0..10] KI tec,pid,ki Set or query the TEC PID integral coefficient. ki [0..1] KD tec,pid,kd Set or query the TEC PID differential coefficient. kd [0..1]

Appendix B. Command language

B.5 Piezo controller

PZT

pzt Sub-commands for querying and adjusting the mLC piezo controller.

REPORT pzt,report Report the state of the piezo controller, flags, scanning waveform type, ramp up/down rate, VLIM , VSET , VSW EEP , scanning inversion, scanning period, external modulation maximum resistance RMAX , external modulation set resistance RSET , enabled/disabled state, piezo PID controller locking slope, overall PID gain coefficient K , KP , KI, KD, dither enabled/disabled state and dither phase. Please refer to section E.1.3 and E.2 for more information about the piezo flags and waveform types.
Use pzt,report,1 to return as a python-compatible dict.

VLIM

pzt,vlim[,val] Set or query the manual voltage limit. VLIM 180V. val [0, 180] in volts.

VSET

pzt,vset[,val] Set or query the required output voltage. VSET VLIM. val [0, VLIM] in volts.

VSWP pzt,vswp Set or query the piezo scanning amplitude. VSW P VLIM. val [0, VLIM] in volts.

SWPINV pzt,swpinv Set or query the piezo scanning polarity inversion. val [0, 1] where 1 is true.

SWEEP pzt,sweep[,wave][,duty] Start piezo scanning. duty is the duty cycle percentage between 1 and 99. wave refer to wavetype (section E.2).

PERIOD pzt,period[,val]

B.5 Piezo controller

Set or query the piezo scanning period. val is time in milliseconds.
HOLD pzt,hold Stop piezo scanning and set the output voltage to VSET .
ENABLE pzt,enable Enables the piezo controller.
DISABLE pzt,disable Disables the piezo controller.
ONOFF pzt,onoff[,val] Turns the piezo controller on/off. val [0, 1] where 1 is on. pzt,onoff,toggle toggles the controller state.

DITHER pzt,dither[,val] Enable/disable the piezo dithering. The default dithering frequency is 262.5 kHz. val [??].

DITHPHASE pzt,dithphase[,val] Set or query the piezo dithering phase. val [-180, 180] degrees.

EXTMODR pzt,extmodr[,val] Set or query the piezo external modulation amplitude potentiometer value. val [??].

LOCK

pzt,lock,{index},{locking type} Enables the servo controller and locks it to either a particular ADC input value or 0 V. The locking type parameter can be either 0 or 1 which corresponds to lock to 0 V or to a particular input value respectively. The index parameter is the index in the ADC input vector array which the servo should be locked to. For example if the index points to the value of 1.5 V then the servo controller will

Appendix B. Command language

be locked to 1.5 V. If the locking type is set to 0 then the index parameter is ignored.
PID pzt,pid Sub-commands for querying and adjusting the piezo PID parameters.
SLOPE pzt,pid,slope Set or query the piezo PID locking slope which can be either rising (1) or falling (-1).
K pzt,pid,k Set or query the piezo PID overall gain. k [0..2] KP pzt,pid,kp Set or query the piezo PID proportional coefficient. kp [0..1] KI pzt,pid,ki Set or query the piezo PID integral coefficient. ki [0..1] KD pzt,pid,kd Set or query the piezo PID differential coefficient. kd [0..1]

B.6 Laser diode controller

Sub-commands for querying and adjusting the mLC laser diode con-

troller.

REPORT ld,report Report the state of the laser diode controller, flags, scanning waveform type, ramp up/down rate, VCOMPL, IMAX , ILIM , IBIAS, scanning inversion, scanning period, ISET , IMON, VMON and the enabled/disabled state of the controller. Please refer to section E.1.4 and E.2 for more information about the laser diode controller flags and waveform types.
Use ld,report,1 to return as a python-compatible dict.

VCOMPL ld,vcompl Set or query the compliance voltage. VCOMPL 8.5 V.
ISET ld,iset Set or query the required laser diode current. ISET ILIM.
IMAX ld,imax Set or query the absolute maximum laser diode current. This current should not exceed the maximum operating current of the laser diode.

ILIM

ld,ilim Set or query the manual limit of the laser diode current. ILIM IMAX .

ISWP

ld,iswp Set or query the laser diode current scanning amplitude. ISW P ILIM .

SWPINV ld,swpinv Set or query the laser diode scanning polarity inversion.

SWEEP ld,sweep[,wave][,duty] Start laser diode current scanning. duty is the duty cycle percentage between 1 and 99. wave refer to wavetype (section E.2).

Appendix B. Command language

PERIOD ld,period[,val] Set or query the laser diode current scanning period. val is time in milliseconds.
HOLD ld,hold Stop laser diode scanning and set the output current to ISET .
ENABLE ld,enable Enables the laser diode current controller.
DISABLE ld,disable Disables the laser diode current controller.
ONOFF ld,onoff[,val] Turns the laser diode current controller on/off. val [0, 1] where 1 is on. ld,onoff,toggle toggles between on and off.

B.7 Ethernet configuration
The default ethernet configuration is DHCP enabled. If DHCP negotiation fails, the fall-back static IP address is 10.1.1.190 with port 7802. TCP/IP parameters can be reconfigured using the commands below. For the following, if the argument is absent, the command will return the current value or status.

static
mask gw mac

ETH,static,”xxx.xxx.xxx.xxx” Set static IP address based on decimal dotted-quad string (e.g. “10.1.1.190”). Note that the double-quotes are part of the syntax and must be included to delimit the IP address string.
ETH,mask,”xxx.xxx.xxx.xxx” Set IP mask based on dotted-quad string (e.g. “255.255.255.0”).
ETH,gw,”xxx.xxx.xxx.xxx” or ETH,gate,”xxx.xxx.xxx.xxx” Set the IP gateway based on dotted-quad string (e.g. “10.1.1.1”).
ETH,mac,”xx:xx:xx:xx:xx:xx” Set the MAC address.

B.7 Ethernet conguration

port dhcp web
status info restart

ETH,port,portnumber Set the TCP/IP port number (default 7802) for device communication.
ETH,dhcp,[off,on] ETH,web,[off,on] Enable or disable DHCP or the integrated web server; both default to enabled. The argument can be 0, 1, off, on, dis, en where dis, en are for disable or enable.
ETH,stat or ETH,ipaddr or ETH,ip Connection status.
ETH,info Extended connection information.
ETH,res Restart the ethernet interface.

Appendix B. Command language

C. Communications

The mLC can be connected to a computer by USB or ethernet (TCP/IP) for use with the provided mogmlc app or integrated into existing control software. If you are experiencing difficulty in connecting to your device, please review the detailed instructions available at www.moglabs.com/support/software/connection.

C.1 Protocol

Communication follows a query/response protocol, where the user sends a text string to the unit, and the unit returns a text response.
Messages are CRLF-terminated; that is, all commands must end with ASCII code 0x0D 0x0A. The C syntax is rl. Most terminal applications automatically append these characters. Responses from the unit should be buffered until CRLF is received. It is strongly recommended to check command responses to ensure correct operation.
Statements are either commands or queries. A command is a statement that causes some action to occur, and the unit will respond with either “OK” or “ERR” as appropriate. It is strongly recommended that all software should wait for this response and check for success before continuing. The python and LabVIEW bindings available on the MOGLabs website take care of buffering and error checking automatically. The MOGLabs Commander application (mogcmd), available from the mLC app or as a separate tool from our website, provides a convenient interface for sending commands and receiving responses (Figure C.1).

C.2 TCP/IP

The mLC can be accessed over ethernet via the IPv4 protocol. When ethernet is connected, the mLC will attempt to obtain an IP ad-
35

Appendix C. Communications

Figure C.1: The mogcmd application, showing successful and unsuccessful commands and queries.
dress by DHCP. If DHCP fails, an internally defined address (default 10.1.1.190) will be used. In both cases, the address will be shown on the device display (e.g. 10.1.1.190:7802), showing the address and port number for communicating with the device.
C.2.1 Changing IP address
If your network does not use a DHCP server, you may need to manually change the IP address. This can be done with the MOGLabs Commander (see above), first allowing the device to revert to the static IP address (usually 10.1.1.90) and then using the ethernet configuration commands in section B.7. Note that in this case, the host computer must have an IP address different to that of the mLC but within the same network subnet. Please refer to our website, https: //www.moglabs.com/support/software/connection for more information.

C.3 USB
C.3 USB

37
The mLC can be directly connected to a host computer using a USB cable (type A-male). The correct USB device driver is packaged with the mogmfe software package or can be downloaded from www. moglabs.com/support/software/connection. Connecting the mLC will install a new COM port on the machine. To determine the port number of the device, go to Device Manager (Start, then type Device Manager into the Search box). You should see a list of devices including “Ports” (Figure C.2).

Figure C.2: Screenshot of Device Manager, showing that the mLC can be communicated with using COM4. The port number might change when plugging into a different USB port, or after applying a firmware update.
The mLC can be identified as a COM port with the following name, STMicroelectronics Virtual COM Port (COMxx)
where xx is a number (typically between 4 and 15).
If the port appears in Device Manager with a different name, then the driver was not successfully installed. If this occurs, disconnect the mLC from the host computer and reinstall the device driver.

Appendix C. Communications

Please refer to our website, https://www.moglabs.com/support/ software/connection for more information on connecting.

D. Connector pinouts

D.1 Power

Power is provided by the USB-C connection. Only high quality USBC (USB 3.0-3.2) cables with a power delivery capacity of at least 60 W should be used.

D.2 Interlock/key
The front-panel interlock socket is a standard 3.5 mm cylindrical stereo headphone jack. The outer conductor is supplied with 3.3 V via a 1 k resistor. The mLC board will be enabled by shorting the respective signal pin to the outer conductor.
Digikey cable CP-2207-ND provides a 3.5 mm plug with wire ends.
1 +3.3 V via 1 k 2 Key input 3 Interlock input

321

Figure D.1: Interlock/key 3.5 mm stereo connector on front panel. Note: Do not apply a voltage across the interlock pins, or the mLC may be irreversibly damaged!
D.3 SMA signal input
The input signal SMA connector can be multiplexed to different internal circuits, depending on required application. The following table
39

Appendix D. Connector pinouts

shows the options.

NC AC DC Imod

Not connected High speed ADC AC-coupled input High speed ADC DC-coupled input Direct diode current modulation

E. Troubleshooting
E.1 State flags
Flags are used to monitor the states of every mLC control component (TEC, laser diode, piezo) as well as the overall state of the controller itself and can be very helpful in troubleshooting. The flags are constantly updated and can be accessed via report commands (see Chapter B). The flags are reported in hexadecimal format. The mLC flags provide information about global triggers (interlock, power good etc.). The submodule flags provide information about the internal monitors and abnormal conditions. Some bits in the flags are constantly updated showing the current state of the signal. Other bits are showing if a certain signal has been triggered, which helps to determine what signal caused the shutdown. The trigger signals can only be reset by re-enabling the interlock. A detailed description of each flag is given below.
41

Appendix E. Troubleshooting

E.1.1 Global (MLC) flags
Flag name FLAG GLOB INTRLK ENABLED FLAG GLOB POWERGOOD FLAG GLOB KEYSW
FLAG GLOB INTRLK

HEX 0x01 0x02 0x04
0x08

Description Interlock enabled Power good Keyswitch enabled Interlock input

E.1.2 Temperature controller flags

Flag name FLAG TEC PGOOD FLAG TEC SHORT CIRCUIT FLAG TEC OPEN CIRCUIT FLAG TEC NTC DISCONNECTED
FLAG TEC TEMPERATURE OVERRUN

HEX 0x01 0x02 0x04 0x08
0x10

Description Power good TEC short-circuit TEC open-circuit Thermistor disconnected Temperature overrun

E.1.3 Piezo controller flags
Flag name FLAG PZT PGOOD

HEX Description 0x01 Power good

E.2 Scanning waveforms
E.1.4 Laser diode controller flags Flag name FLAG LD ILIM TRIG FLAG LD SHORT CIRCUIT FLAG LD OPEN CIRCUIT FLAG LD LOW COMPLIANCE

HEX 0x01 0x02 0x04 0x08

Description
Current limit triggered
Laser diode shortcircuit
Laser diode opencircuit
Current source compliance voltage too low

E.2 Scanning waveforms
The mLC controller supports scanning the piezo voltage (0 to VLIMV) and laser diode current (0 to 25mA). The scanning waveform can be one of the following.

Wave name TYPE NONE TYPE SAWTOOTH TYPE SINE TYPE TRIANGLE

Value 0 1 2 3

Description None (DC) Sawtooth shape Sine shape Triangular shape

For additional assistance please contact MOGLabs. Please include the device serial number and firmware versions.

MOG Laboratories Pty Ltd 49 University St, Carlton VIC 3053, Australia Tel: +61 3 9939 0677 info@moglabs.com

Documents / Resources

moglabs M Series Mini Laser Controller [pdf] Instruction Manual
mLC, mCC, mTC, M Series Mini Laser Controller, M Series, Mini Laser Controller, Laser Controller, Controller

References

User Manual

M Series Mini Laser Controller

Specifications:

Product Information:

Safety Precautions:

Protection Features:

Emission Indicator:

Product Usage Instructions:

Frequently Asked Questions (FAQ):

Q: Can I use the Mini Laser Controller for medical
applications?

Q: What should I do if I encounter a fault condition while
using the controller?

Documents / Resources

References

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