THORLABS MCLS Series User manual

MCLS Series Multi-Channel
Fiber-Coupled Laser Source
Operating Manual

4-Channel Fiber-Coupled Laser Source
Table of Contents
Chapter 1 Warning Symbol Definitions.............................................................................................1
Chapter 2 Safety...................................................................................................................................2
Chapter 3 Description .........................................................................................................................3
Chapter 4 Setup ...................................................................................................................................5
4.1. Setting the AC Line Voltage and Installing Fuses...................................................... 5
4.2. Initial Set-up.................................................................................................................. 5
Chapter 5 Operation............................................................................................................................6
5.1. Front and Back Panel Overview .................................................................................. 6
5.2. Turning On the Source................................................................................................. 7
5.3. Viewing Channel Information....................................................................................... 7
5.4. Adjusting the Laser Output Power and Temperature................................................. 7
5.5. Turning the Laser Off ................................................................................................... 8
5.6. Modulating the Laser Output....................................................................................... 9
Chapter 6 Making the Safety Interlock Connections.....................................................................10
Chapter 7 Remote Communications ...............................................................................................11
7.1. Installing the USB Drivers.......................................................................................... 11
7.2. Command Line Interface............................................................................................ 11
7.3. Keywords (Commands and Queries) ........................................................................ 12
Chapter 8 General Maintenance.......................................................................................................14
8.1. Cleaning...................................................................................................................... 14
Chapter 9 Specifications...................................................................................................................15
Chapter 10 Mechanical Drawing........................................................................................................16
Chapter 11 Declaration of Conformity ..............................................................................................17
Chapter 12 Regulatory ........................................................................................................................18
Chapter 13 Thorlabs Worldwide Contacts........................................................................................19

4-Channel Fiber-Coupled Laser Source Chapter 1: Warning Symbol Definitions
Rev O, January 24, 2024 Page 1
Chapter 1 Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol
Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
Caution: Spinning Blades May Cause Harm

4-Channel Fiber-Coupled Laser Source Chapter 2: Safety
Page 2 TTN182036-D02
Chapter 2 Safety
All statements regarding safety of operation and technical data in this instruction manual will only apply when the
unit is operated correctly.
SHOCK WARNING
High voltage inside. To avoid electrical shock, before powering unit, make sure that the protective
conductor of the 3-conductor power cord is correctly connected to the protective earth contact of
the socket outlet. Improper grounding can cause electric shock resulting in severe injury or even
death. Do not operate without cover installed.
WARNING
This unit must not be operated in explosive environment.
WARNING
Avoid Exposure –Laser Radiation Emitted from apertures.
The unit is supplied with a 115 V parallel blade line cord for North American use only. For all other applications use
an IEC 320 compatible line cord fitted with a plug appropriate for your particular AC wall socket.
Make sure that the line voltage rating marked on the rear panel agrees with your local supply and that the
appropriate fuses are installed. Changing of the mains fuse can be done by the user (see Setting the AC Line
Voltage and Installing Fuses). With the exception of the mains fuses, there are no user serviceable parts in this
product.
Do not operate in wet or damp conditions. Do not obstruct the air-ventilation slots in the housing!
This device can only be returned when packed into the complete original packaging, including all foam packing
inserts. If necessary, ask for a replacement package.
Mobile telephones, cellular phones or other radio transmitters should not to be used within the range of three meters
of this unit since the electromagnetic field intensity may exceed the maximum allowed disturbance values according
to EN50082-1.
LASER RADIATION
AVOID EXPOSURE TO THE BEAM
CLASS 3B LASER PRODUCT
405 –1550 nm <100 mW

4-Channel Fiber-Coupled Laser Source Chapter 3: Description
Rev O, January 24, 2024 Page 3
Chapter 3 Description
The Thorlabs 4-Channel Fiber Coupled Laser Sources provide easy coupling and simple control of laser diode
driven fiber optics. Each system is equipped with up to four fiber output light sources with wavelength available from
visible to IR. The laser sources come standard with FC/PC connectors, and each system can be made with single
mode fiber or PM fiber and any combination of four lasers. Below is a sample list of available wavelengths; please
visit our website for a full list of currently available options.
Item #
Typical
λ
λ Range
(nm)
Min
Power1
Typical
Power
Laser
Type
Monitor
PD22
Fiber
MCLS1-406
406 nm
395 - 415
4.0 mW
6.0 mW
Fabry-Perot
Yes
S405-XP
MCLS1-473-20
473 nm
468 - 478
15.0 mW
20 mW
Fabry-Perot
Yes
460HP
MCLS1-488
488 nm
483 - 493
18.0 mW
22 mW
Fabry-Perot
Yes
460HP
MCLS1-520A
520 nm
510 - 530
10.0 mW
15.0 mW
Fabry-Perot
Yes
460HP
MCLS1-635
635 nm
630 - 640
2.5 mW
3.5 mW
Fabry-Perot
Yes
SM600
MCLS1-638
638 nm
628 - 648
10.0 mW
15.0 mW
Fabry-Perot
Yes
SM600
MCLS1-642
642 nm
635 - 645
15.0 mW
20.0 mW
Fabry-Perot
Yes
SM600
MCLS1-658
658 nm
648 - 668
9.5 mW
14.0 mW
Fabry-Perot
Yes
SM600
MCLS1-660
660 nm
653 - 663
15.0 mW
17.0 mW
Fabry-Perot
No
SM600
MCLS1-670
670 nm
660 - 680
1.5 mW
2.5 mW
Fabry-Perot
Yes
SM600
MCLS1-670-4
670 nm
660 - 680
4.0 mW
5.0 mW
Fabry-Perot
Yes
SM600
MCLS1-685
685 nm
675 - 695
10.0 mW
13.5 mW
Fabry-Perot
Yes
SM600
MCLS1-705
705 nm
695 - 715
10.0 mW
15.0 mW
Fabry-Perot
Yes
SM600
MCLS1-730
730 nm
720 - 740
12.5 mW
15.0 mW
Fabry-Perot
Yes
SM600
MCLS1-785
785 nm
770 - 800
6.0 mW
7.5 mW
Fabry-Perot
Yes
780HP
MCLS1-785-25
785 nm
780 - 790
20.0 mW
25.0 mW
Fabry-Perot
No
780HP
MCLS1-808-20
808 nm
803 - 813
20.0 mW
25.0 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-830
830 nm
820 - 840
8.0 mW
10.0 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-850
850 nm
840 - 860
7.5 mW
10.5 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-850-MM
850 nm
847 - 857
45.0 mW
50.0 mW
Fabry-Perot
Yes
GIF625
MCLS1-852
852 nm
847 - 857
20.0 mW
25.0 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-915
915 nm
910 - 920
30.0 mW
40.0 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-940
940 nm
930 - 950
25.0 mW
30.0 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-980
980 nm
965 - 995
6.0 mW
9.0 mW
Fabry-Perot
Yes
980HP
MCLS1-980-20
980 nm
970 - 990
15 mW
20 mW
Fabry-Perot
Yes
SM800-5.6-125
MCLS1-1064
1064 nm
1059-1069
20.0 mW
25.0 mW
Fabry-Perot
Yes
HI1060
MCLS1-1310
1310 nm
1290-1330
2.5 mW
3.0 mW
Fabry-Perot
Yes
SMF-28e+
MCLS1-1310-15
1310 nm
1290-1330
13.0 mW
15.0 mW
Fabry-Perot
No
SMF-28e+
MCLS1-1310DFB
1310 nm
1290-1330
1.5 mW
2.0 mW
DFB
Yes
SMF-28e+
MCLS1-1550
1550 nm
1520-1580
1.5 mW
2.0 mW
Fabry-Perot
Yes
SMF-28e+
MCLS1-1550-10
1550 nm
1530-1570
8.0 mW
10.0 mW
Fabry-Perot
No
SMF-28e+
MCLS1-1550DFB
1550 nm
1540-1560
1.5 mW
2.0 mW
DFB
Yes
SMF-28e+
MCLS1-1625
1625 nm
1605-1645
10 mW
15 mW
Fabry-Perot
No
SMF-28e+
1
This is the minimum guaranteed output power of the laser when the adjustment knob is set at the maximum.
2
When no photodiode is present, the display will show the current instead of the power and will display a message “NO PD”.

4-Channel Fiber-Coupled Laser Source Chapter 3: Description
Page 4 TTN182036-D02
Each laser diode operates from an independent, high-precision, low-noise, constant-current source and
temperature control unit. An intuitive LCD interface allows the user to view and set the parameters for each laser.
The user can adjust the laser current and temperature control independently for each output. The display indicates
the channel number selected, the output wavelength of the source, the operating power calculated from the laser
diode monitor diode (if applicable), and the actual temperature the laser is set to.
This device includes a microcontroller to fully control the laser’s optical power, temperature, and monitor the system
for fault conditions. The laser source includes a USB connection that allows remote adjustment of power,
temperature, and enabling. On the rear panel, analog inputs are available to modulate the lasers with an external
signal. This is added to the internal set points. To prevent damage, the microcontroller will disable the output if the
analog input plus the internal set point exceeds the laser limits.
While most output sources fall within the class 3R laser rating, the system was fully designed to meet 3B laser class
requirements. There is an interlock located on the rear panel that must be shorted in order for any laser output to
be enabled. This can easily be configured to be triggered by doors to disable the lasers in unsafe conditions. The
power switch is a keylock system to prevent accidental or unwanted use. Each source has its own enable button
allowing the user to choose the light source or sources they wish to be active as well as a master enable which
must also be set. Each channel includes a green LED indicator to easily determine its current state. There is a 3
second delay before the lasers turns on, and the user is warned by the LED rapidly blinking.
The MCLS includes a universal power supply allowing operation over 100 - 240 VAC without the need for selecting
the line voltage. The fuse access is conveniently located on the rear panel. This unit is supplied with a region-
specific U.S. or standard European line cord, the pre-configured laser source with all selected lasers installed, and
the manual.

4-Channel Fiber-Coupled Laser Source Chapter 4: Setup
Rev O, January 24, 2024 Page 5
Chapter 4 Setup
4.1. Setting the AC Line Voltage and Installing Fuses
Your MCLS Series Laser Source has been shipped from Thorlabs configured for 100 to 240 VAC operation. There
is no line switch adjustment to be made. However it may be necessary to replace an open fuse. To do this you must
perform the following procedure.
•Remove the AC power cord if it is connected to the unit.
•Locate the fuse tray directly below the AC power cord connection on the rear panel of the unit.
•Carefully use a flat blade screwdriver to open the fuse tray.
•Remove the existing fuse and install the appropriate 250 mA fuse. The replacement fuse must be a 5 mm
x 20 mm, 250 VAC Type T Fuses (IEC 60127-2/III, low breaking capacity, slow blow)
•Push the fuse tray back into place making sure that it snaps and seats correctly.
•Connect the appropriate power cord into the AC receptacle and plug the unit in.
4.2. Initial Set-up
•Locate the unit on a dry, level working surface.
•Make sure the POWER key switch on the front of the unit is in the OFF position (key perpendicular to
working surface).
•Plug the female end of the AC line cord provided into the AC Input Receptacle on the rear of the unit. Plug
the male end into a properly grounded AC socket.
•Install the interlock key into the interlock connector located on the rear panel. See Chapter 6 for details.
•Connect a Fiber Optic cable to the LASER APERTURE on the front panel of the unit and verify that the
dust caps are installed onto all unused fiber connections.

4-Channel Fiber-Coupled Laser Source Chapter 5: Operation
Page 6 TTN182036-D02
Chapter 5 Operation
5.1. Front and Back Panel Overview
Figure 1: Front and Rear Panels of Laser Source
Digit Display w/ Backlight
Displays channel, output power,
wavelength, and temperature.
Laser Output Port
FC/PC fiber optic connector.
Laser Output Cover
Cover should be installed
when fiber is removed.
Laser Enable Switch
Press to activate selected lasers.
Laser Emission Indicator
Indicates the channel is selected. It will blink for 3
seconds prior to the laser turning on.
Keylock Power Switch
Key only removes when off.
Control Knob / Switch
Selects channel, adjusts current and temperature.
Display Select Switch
Selects the channel desired
to be enabled.
Remote Interlock Input
(See Chapter 6 for details).
AC Power Cord Connector
USB Input Connector
Allows full operation through a PC interface.
Modulation Input - 0 to 5 V Max
Accepts complex waveforms. See
section 5.6 for details.
Cooling Vent - Do Not Block
The temperature control system moves air from
vent holes on the bottom. Periodically remove
dust buildup from vents for best operation.
Fuse Tray
See section 4.1 for replacement details.

4-Channel Fiber-Coupled Laser Source Chapter 5: Operation
Rev O, January 24, 2024 Page 7
5.2. Turning On the Source
•Turn the POWER key switch clockwise. The LCD display will scroll “Thorlabs MCLS” across the screen,
followed by the Ch1 information.
•Make sure the Interlock Input is short-circuited; see Chapter 6 for detailed instructions.
•Select the desired output channels by pressing and releasing the ENABLE switch located above the desired
fiber output sources. An indicator located next to the switch will light up.
•Press and release the SYSTEM ENABLE switch to activate the lasers. There will be an approximately 3
second delay before the lasers power up. During this time the SYSTEM ENABLE indicator will light up and
the selected channel indicator lights will blink rapidly.
•The default display mode is laser power (mW), however the thermo-electric cooler is activated when the
unit turns on.
5.3. Viewing Channel Information
The MCLS uses a single LCD display to access the information for each output channel. At any time the display
can be adjusted to view another channel by simply rotating the control knob located to the left of the display. The
display will scroll through the channels until the desired channel is selected. The following information will be
available:
•Top left –Indicates the channel selected. As an additional indicator, the channel enable indicator selected
will periodically blink on if disabled and off if enabled.
•Top Right –Indicates the wavelength of the selected channel. This is set at the factory when the lasers are
installed.
•Bottom Left –Indicates the power level of the laser diode. If it is disabled this will read “0.00mW” and if the
selected laser diode does not include a monitor diode this will read “No PD”. When enabled the current
power level determined from the monitor photodiode will indicate the approximate power level of the output.
Note: The power shown on the display is the optical power at the laser aperture calibrated to the monitor photodiode.
The actual power at the end of your fiber optic cable may be less, depending on the quality of the connection. All
fiber optic cables installed should be cleaned first since dust and dirt particles in the connector will effect coupling
efficiency and possibly damage the fiber connectors.
•Bottom Right –Indicates the actual temperature the laser is stabilized to and is displayed in C. The system
defaults to a temperature of 25.00 C until changed by the user. The temperature control is always active
and requires 5 to 10 minutes to properly stabilize.
5.4. Adjusting the Laser Output Power and Temperature
•Rotate the control knob to select the appropriate channel. Clockwise rotation increases the channel while
counterclockwise decreases the channel. The selected channel is indicated on the display as well as with
a periodic blink of the channel indicator light.
Note: The adjustment knob utilizes an intelligent speed control. Adjusting the knob slowly will increment values at
the maximum resolution while adjusting fast will make larger movements. This allows both a fine and course control.
•When the appropriate channel is selected, press the control knob in. The bottom left location will start
blinking and will change to current. Ex: xx.xxmA. Adjust the control knob until the desired current is
achieved. The power will adjust real-time. The first time default setting will be power full off. Adjusting the
knob clockwise will immediately set the power to the laser threshold and then incrementally to the max
operating current. Adjusting the knob counterclockwise will incrementally decrease the signal until it hits
the threshold, and then immediately to laser off. On power down, the current setting will be remembered.
Note that there is a timeout on the display, after which the display will revert back to the viewing mode. This is to
prevent accidental adjustment of the power.

4-Channel Fiber-Coupled Laser Source Chapter 5: Operation
Page 8 TTN182036-D02
•Press the knob again to switch to temperature adjustment. The set point temperature will be displayed and
will be blinking; for example, 25.00 C. Adjust the control knob to increase or decrease the temperature set
point. The temperature default is 25.00 C but can be adjusted over a range of 20.00 to 30.00 C with a
resolution of 0.01 C.
Note, as above there is a timeout where the display will revert to the viewing display and lock out adjustment to the
temperature.
•Pressing the control knob again will exit the adjustment mode and revert back to the viewing mode, locking
in the selected parameters. This can also be achieved by allowing the display to time out at any point in the
process. Depending on the magnitude of the change in temperature set point, it will take anywhere from a
few seconds to a few minutes for the system to settle into the new operating temperature.
5.5. Turning the Laser Off
•Standby Mode –By adjusting the control knob fully counter clockwise the power will adjust down to the
threshold current and then to off, or standby mode. The threshold current is the point at which the internal
laser diode starts lasing. Below this it operates in a LED mode. For convenience the system is set up to
adjust from the threshold to the max current. In addition, when adjusting below the threshold, the current
will be set to almost 0 mA. Since the system utilizes a constant current control, there will always be a
minimum current to maintain the current control loop. The output emission is typically very low, or
nonexistent. The laser is still enabled and operating at the minimum possible current. This can be useful
while using the external modulation. The full 5 V can be applied without compensating for the internal set
point. However, the external signal will need to provide a DC offset to bias the laser above the threshold
current for best results. Input signals will see clipping on their lower edges below threshold. Pulse response
time may also be effected since there is typically a time delay during the LED to laser emission change.
•Disable/Enable Mode - The Laser output should be turned off by pressing and releasing the SYSTEM
ENABLE switch. Outputs can be individually turned off at any time by pressing their ENABLE button. The
laser temperature will be maintained even when the laser is disabled.
•Power Down - When completely powering down an enabled unit, first press and release the SYSTEM
ENABLE switch and then turn the POWER key switch counterclockwise, which will turn OFF the entire unit.
Anytime the unit is turned OFF and then turned back ON, the Laser will be disabled until the SYSTEM
ENABLE switch is pressed and the desired channels are enabled.

4-Channel Fiber-Coupled Laser Source Chapter 5: Operation
Rev O, January 24, 2024 Page 9
5.6. Modulating the Laser Output
The MOD IN input can be used to modulate the laser output, or set the laser output remotely using a 5 V power
source. The 5 V maximum inputs correspond to the maximum calibrated power of each channel, which operate
using a constant current drive technique. The resulting actual output power is dependent on the set current and
operating temperature. In addition, in order to eliminate a dead zone in the power control knob, the output of
the unit is offset to the threshold current of the coupled laser diode. Adjusting the knob below threshold will
immediately set the current to almost 0 mA, or Standby mode as described in section 5.5. Therefore, there are
two modes of modulation available. First setting the control to “Standby” allows the analog modulation to utilize
the full 0 to 5 V input range. The drawback is that a minimum voltage will be required to operate above the
threshold current but allows more flexibility by the user. The second mode is to adjusting the control knob so
that the laser is at threshold or above. The analog modulation voltage will be limited to less than 5 V, but a DC
offset will not be required. This should be kept in mind when using the modulation input since it will limit the
actual input voltage range.
•Connect a signal generator or 0 to 5 V power source to the unit using a BNC type connector.
•Set the PWR ADJ knot on the front panel to its full counter clockwise setting for standby mode, or increase
slightly to the threshold current mode.
•Press the ENABLE switch to turn on the laser, wait for the safety delay to time out.
•For Threshold Offset - Apply the appropriate signal to the MOD IN input. If too much voltage is applied
internal current limiting will prevent damage to the laser diode and the laser diodes will be immediately
disabled. If an internal threshold is set the acceptable drive voltage range will be less than 5V. To calibrate
your input apply a DC voltage to the MOD IN and slowly increase until the system disables. This will be the
max voltage allowable for that channel.
•For Standby Operation –Apply and appropriate signal between 0 and 5 V to the MOD IN for the desired
channel. Determine the DC offset by increasing the voltage slowly until a large power jump is seen on the
output. An easier method it to apply a 1 Vpp sinusoid and adjust the DC offset until the sinusoid appears
and then the bottom edge is no longer clipping. This method requires applying the laser output to a
photodetector and monitoring with an oscilloscope. Next maximize the amplitude so that the peak is 5 V or
less as desired.

4-Channel Fiber-Coupled Laser Source Chapter 6: Making the Safety Interlock Connections
Page 10 TTN182036-D02
Chapter 6 Making the Safety Interlock Connections
The MCLS series laser sources are equipped with a remote interlock connector located on the rear panel, see
Figure 2:. All units have this feature regardless of their FDA and IEC classifications. In order to enable the laser
source, a short circuit must be applied across the terminals of the Remote Interlock connector. In practice this
connection is made available to allow the user to connect a remote actuated switch to the connector (i.e. an open
door indicator). The switch (which must be normally open) has to be closed in order for the unit to be enabled. Once
the switch is in an open state the laser source will automatically shut down. If the switch returns to a closed condition
the laser source must be re-enabled at the unit by pressing the SYSTEM ENABLE switch.
All units shipped from Thorlabs are configured with a shorting device installed in the Interlock connector. If you are
not going to use this feature then you can leave the shorting device installed and the unit will operate normally as
described in the procedures above.
If you wish to make use of the Interlock feature you will need to acquire the appropriate connector mate and wire it
to your remote interlock switch. Next, remove the shorting device by pulling it out with a pair of needle nose pliers
and install the connector into the interlock input.
The interlock input only accepts a 2.5 mm mono phono jack. This connector is readily available at most electronics
stores.
The electrical specifications for the interlock input are shown in the following table.
Specification
Value
Type of Mating Connector
2.5 mm Mono Phono Jack
Open Circuit Voltage
+5 VDC with Respect to Chassis Ground
Short Circuit Current
~8 mA DC
Connector Polarity
Tip is +5 V, Barrel is Ground
Interlock Switch Requirements
Must be N.O. Dry Contacts
Under no circumstances should any
external voltages be applied to the
interlock input.
Figure 2: Remote Interlock Connector
Ground
+5 Volts

4-Channel Fiber-Coupled Laser Source Chapter 7: Remote Communications
Rev O, January 24, 2024 Page 11
Chapter 7 Remote Communications
7.1. Installing the USB Drivers
Prior to running the command line interface, the USB drivers must be installed. The MCLS Fiber-Coupled Laser
Source must not be connected to the PC while installing the drivers. Refer to the link provided on the Download
Card that was included with your unit, or by visiting www.thorlabs.com/manuals to download and install the latest
software for the MCLS Series Fiber-Coupled Laser Source. From the dialog box that is displayed, select the Install
Drivers button. Follow the onscreen prompts to install the driver. After the driver is installed, attach the MCLS Fiber-
Coupled Laser Source to the PC and power it on. Your PC will then detect the new hardware and will prompt you
when the installation is complete.
7.2. Command Line Interface
Once the USB drivers have been installed, the unit connected to the PC, and the power turned on, configure the
terminal emulator as follows:
•Baud Rate = 115.2K Bits Per Second
•Data Bits = 8
•Parity = None
•Stop Bits = 1
•Flow Control = None
If the connection is correct you will see the following after pressing the “Enter” key.
Command error CMD_NOT_DEFINED
Followed immediately by the prompt:
>
The basic structure of the interface is a keyword followed by either an equals sign “=” or a question mark “?”. The
“=” or “?” will determine if the string is a command or a query. All strings (commands and queries) must be terminated
by a carriage return (CR) or pressing the ENTER key on the computer.
The command structure is as follows:
Keyword = argument (CR)
Where “keyword” defines the function and “argument” is a numerical value followed by a carriage return (CR). See
listing below.
The query structure is a follows:
Keyword? (CR)
The “keyword” defines the function and the question mark (?) indicates a query. The string is terminated with a
carriage return (CR). See listing below.
There are a few exceptions to this which are noted below, also noted are unique shortcut keys.
The prompt symbol “>” will appear on power up and after a command is accepted by the system indicating it is
ready to receive another command line.

4-Channel Fiber-Coupled Laser Source Chapter 7: Remote Communications
Page 12 TTN182036-D02
7.3. Keywords (Commands and Queries)
The following list shows all of the available commands and queries, and summarizes their functions:
Command
Syntax3
Description
Get Commands
?
List the available commands
Get ID
id?
Returns the model number and firmware version.
Get Channel
channel?
Returns the active channel.
Set Channel
channel=n
Select the channel specified by n.
Get Target Temp
target?
Returns the set temperature for the active
channel (C).
Set Target Temp
target=n
Sets the set temperature (n) for the active
channel (C).
Get Temp
temp?
Returns the actual temperature for the active
channel (C).
Get Current
current?
Returns the current for the active channel (mA).
Set Current
current=n
Sets the current (n) for the active channel (mA).
Get Power
power?
Returns the power for the active channel (mW).
Get Enable
enable?
Returns the current state of the active channels
Enable button.
Set Enable
enable=n
Sets the state of the active channels Enable
button (0: disabled, 1: enabled).
Get System
system?
Returns the current state of the System Enable
button.
Set System
system=n
Sets the state of the System Enable button (0:
disabled, 1: enabled).
Get Specs
specs?
Returns the Laser Diode Specifications for the
active channel.
Get Step
step?
Returns the increment used to adjust the
temperature and current when the arrow keys
are pressed.
Set Step
step=n
Sets the increment (n) used to adjust the
temperature and current when the arrow keys
are pressed.
Save
save
Saves the current settings.
Get Status
statword
Returns a status word that indicates the state of
all enable buttons.
If the keyword, format, or argument is incorrect or out of range, the unit will return an error string. The function is
determined by the value set with the mode command in the above table.
3
All commands and queries are in lowercase letters.

4-Channel Fiber-Coupled Laser Source Chapter 7: Remote Communications
Rev O, January 24, 2024 Page 13
In addition to the above commands there is also special functionality added to the arrow keys of the computer’s
keyboard.
•Up Arrow Key –Increments the current for the active channel by n.
•Down Arrow Key –Decrements the current for the active channel by n.
•Right Arrow Key –Increments the temperature for the active channel by n.
•Left Arrow Key –Decrements the Temperature for the active channel by n.
Where n is set by the command “Set Step”.

4-Channel Fiber-Coupled Laser Source Chapter 8: General Maintenance
Page 14 TTN182036-D02
Chapter 8 General Maintenance
Aside from the AC Input fuse there are no user serviceable parts in this product. If you suspect something has failed
on the unit, please contact Thorlabs for advice on returning the unit for evaluation. Always clean fiber optic
connectors that will be inserted into the system and install the dust cap whenever the source is not being used.
Allowing dust and dirt into the fiber ports will degrade coupling efficiency and possibly damage the fiber patch cords,
both inside and outside. If you suspect this to be true, Thorlabs can clean and inspect the fiber connections, and
repair if necessary.
8.1. Cleaning
The unit can be cleaned using a soft, slightly damp cloth. Avoid using any solvents on or near the unit. Keep the
vent holes located on the bottom of the unit and on the rear panel free of dust buildup. Restricted airflow will cause
the temperature controls to operate inefficiently and in extreme cases, lose temperature control.
Always clean the ferrule end of your fiber patch cable prior to inserting it into the output FC Adapter. Allowing dust
and dirt into the fiber ports will degrade coupling efficiency and possibly damage the fiber patch cords, both inside
and outside. If you suspect this to be true, Thorlabs can clean and inspect the fiber connections, and repair if
necessary.

4-Channel Fiber-Coupled Laser Source Chapter 9: Specifications
Rev O, January 24, 2024 Page 15
Chapter 9 Specifications
General Specifications
AC Input
100 - 240 VAC, 50 - 60 Hz
Input Power
35 VA Max
Fuse Ratings
250 mA
Fuse Type
IEC60127-2/III (250 V, Slow Blow Type ‘T’)
Fuse Size
5 mm x 20 mm
Dimensions (W x H x D)
12.6" x 2.5" x 10.6"
(320 mm x 64 mm x 269 mm)
Weight
8.5 lbs.
Operating Temperature
15 to 35 °C
Storage Temperature
0 to 50 °C
Connections and Controls
Interface Control
Optical Encoder with Pushbutton
Enable and Laser Select
Keypad Switch Enable with LED indication
Power On
Key Switch
Fiber Ports
FC/PC
Display
LCD, 16x2 Alphanumeric Characters
Input Power Connection
IEC Connector
Modulation Input
Connector
BNC (Referenced to Chassis)
Interlock
2.5 mm Mono Phono Jack (See Chapter 6)
Communications
Communications Port
USB 2.0
Com Connection
USB Type B Connector
Required Cable
2 m USB Type A to Type B Cable
(Replacement Item # USB-A-79)
Performance Specifications
Display Power Accuracy
±10%
Current Set Point
Resolution
0.01 mA
Temperature Adjust Range
20.00 to 30.00 °C
Temp Set Point Resolution
±0.01 °C
Noise
<0.5% Typical (Source Dependent)
Rise Time / Fall Time
<5 µsec
Modulation Input
0 - 5 V = 0 - Full Power
Modulation Bandwidth
80 kHz Full Depth of Modulation
For individual laser diode specs, please see the table on page 3

4-Channel Fiber-Coupled Laser Source Chapter 10: Mechanical Drawing
Page 16 TTN182036-D02
Chapter 10 Mechanical Drawing
Figure 3: Mechanical Drawing