THORLABS LDM9T User manual

LDM9T
Laser Mount with TEC
and Controller
User Guide

LDM9T
Table of Contents
Chapter 1 Warning Symbol Definitions ...........................................1
Chapter 2 Safety.................................................................................2
Chapter 3 Description........................................................................3
3.1. Package Contents .......................................................... 4
Chapter 4 Setup..................................................................................5
4.1. Setup Instructions .......................................................... 5
4.2. Special Note for 4-Pin Laser Diodes ................................ 6
4.3. Laser Diodes without a Monitor Photodiode .................. 6
4.4. Mount Power and TEC Control ....................................... 7
4.5. Thorlabs LDC Series Laser Controller Connection ............ 7
4.6. Using a Third-Party Laser Controller............................... 8
Chapter 5 Operation...........................................................................9
5.1. General.......................................................................... 9
5.2. RF Modulation............................................................... 9
5.3. Status and Interlocks ................................................... 10
5.4. Active Cooling System.................................................. 10
5.5. Safe Operating Area (SOA)........................................... 11
5.6. Maintaining the LDM9T ............................................... 12
Chapter 6 Making Safety Interlock Connections ..........................13
Chapter 7 Trouble Shooting............................................................14
Chapter 8 Specifications.................................................................15
Chapter 9 Mechanical Drawing.......................................................19
Chapter 10 Regulatory.......................................................................20
Chapter 11 Thorlabs Worldwide Contacts.......................................21

LDM9T Chapter 1: Warning Symbol Definitions
Rev G, Jan 22, 2017 Page 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

LDM9T Chapter 2: Safety
Page 2 15827-D02
Safety
WARNING
Make sure the laser diode is installed correctly and the polarity switches on the
mount are set as per the laser diode pin configuration provided by the
manufacturer. Connecting the LD driver to mount with incorrect installation may
damage the laser diode.
WARNING
The RF input is directly coupled to the laser. Any excessive transients or noise
will be coupled into the laser and may cause the laser to be overdriven. Also,
the laser can be easily overdriven if excessive RF power is applied to this input.
Use the RF modulation input with care to avoid damaging your laser or mount.

LDM9T Chapter 3: Description
Rev G, Jan 22, 2017 Page 3
Description
Features
•Ø5.6 mm (TO-56) and Ø9 mm (TO-9) Laser Diodes Compatible
•Integrated TEC Controller
•Bias-T Adapter for RF Modulation of Laser Current up to 1 GHz
•TEC Element Prolongs LD Life and Stabilizes Output Power and
Wavelength
The LDM9T is a laser diode mount that features an integrated thermo-electric
cooler (TEC) and temperature controller to precisely regulate the operating
temperature of a laser diode. This mount is designed for users who wish to
temperature control laser diodes without the need for an external TEC controller.
By integrating the TEC, the PID loop settings have to be tuned specifically for the
mount at the factory. The temperature range is limited to approximately 20 to
30 °C due to the size of the package. The TEC control circuit provides a stable,
cost effective, temperature platform for laser diodes. This, combined with current
control, can be used to stabilize or tune the laser diode wavelength.
The LDM9T is compatible with Thorlabs series of LDC controllers. A four pin
socket accepts all Ø9 mm (TO-9) and Ø5.6 mm (TO-56) laser diodes packages.
Easy to use polarity switches allow the laser mount to be configured for the laser
pin assignments shown in the image below. The laser can be directly modulated
to >1GHz using a 50 RF bias-T.
The mount’s safety and protection features include reverse bias protection
diodes, remote safety interlock connection, and a TEC lockout circuit that
prevents enabling of the laser diode unless the temperature controller is also
enabled. The TEC lockout can easily be bypassed by setting an on-board
jumper.
The LDM9T mount has a compact design, with a low speed fan to increase the
cooling capacity, and still offers the features typical to our other products. The
mounting options include multiple #8-32 (M4-0.7 on the /M version) mounting
holes, 30 mm cage system mounting holes, and SM1 threaded aperture.

LDM9T Chapter 3: Description
Page 4 15827-D02
Figure 1 Supported Pin Configurations
3.1. Package Contents
•LDM9T Mount
•Ø9 mm LD Flange
•Ø5.6 mm LD Flange
•Replacement Screws
•HK564 5/64" Hex Key
•Operating Manual

LDM9T Chapter 4: Setup
Rev G, Jan 22, 2017 Page 5
Setup
4.1. Setup Instructions
•Unpack the laser mount and remove the four 2-56 socket head screws
from the top cover using a 5/64" hex driver.
•Remove the two 2-56 socket head screws securing the Ø9 mm flange to
the copper cold plate with a 5/64" hex driver.
•Determine the laser pin configuration from the laser diode
manufacturer’s data sheets and set the LD (Laser Diode) and PD
(Photodiode) switches on the inside of the LDM9T.
Figure 2 Polarity Switch Settings
•The four sockets comprising the laser diode connector are through-hole-
type sockets.
•Most laser diodes are three pins with the case tied to one of the laser
pins and also to one of the photodiode pins. The other laser and
photodiode pin will be isolated from the case. The LDM9T was designed
to operate the laser case at ground potential therefore this common pin
will be inserted into either the 9 o’clock or the 3 o’clock position of the
laser connector, marked G (Ground). Locate the isolated laser pin and
insert it in the 6 o’clock position, marked LD. The isolated photodiode
should now be in the 12 o’clock position, marked PD.
Figure 3 Laser Diode Socket

LDM9T Chapter 4: Setup
Page 6 15827-D02
•Make sure the laser diode is flush with the cold plate. Install the
appropriate mounting flange, either Ø5.6 mm or Ø9 mm, over the laser
diode and secure in place using the provided screws. A spare set of
screws is provided with the mount.
•Lastly, reattach the cover plate using the two 2-56 socket head screws.
WARNING
Make sure the laser diode is installed correctly and the polarity switches on the
mount are set as per the laser diode pin configuration provided by the
manufacturer. Connecting the LD driver to mount with incorrect installation may
damage the laser diode.
4.2. Special Note for 4-Pin Laser Diodes
The LDM9T also supports 4-pin laser diodes. Insert the laser into the 4-pin
socket and note which laser pin is in the 6 o’clock position (laser anode or
cathode). Also, note which photodiode pin is in the 12 o’clock position (anode or
cathode). The mount will tie the laser and photodiode pins located at 9 o’clock
and 3 o’clock together and also to ground. By noting which polarity pins are
inserted in the socket, you can convert the 4-pin layout to one of the 3-pin layouts
in Figure 2 on page 5. Set the LD and PD polarity switches accordingly.
4.3. Laser Diodes without a Monitor Photodiode
Laser diodes without a monitor photodiode will also work with the LDM9T. The
laser diode pins must be positioned between the LD and G positions. Some 2 pin
packages will not align with the laser diode socket, but 3 pin versions can be
mounted.
Pin style G is a special case. To properly operate this laser diode style, the
internal jumper JP2 needs to be installed. This will short the PD pin to G. The
user will need to determine if they want to operate with the LD anode or cathode
grounded. The laser diode needs to be oriented so that the preferred grounded
LD pin is oriented to the PD pin. This will align the remaining laser diode pin into
the LD socket. The laser diode pin oriented toward the PD pin will determine the
switch position.
Laser Lead in PD Socket
LD Switch
PD Switch
Anode
AG
CG
Cathode
CG
AG
It should be noted that both PD pins will now be grounded giving erroneous
readings on controllers with photodiode measurement circuits.

LDM9T Chapter 4: Setup
Rev G, Jan 22, 2017 Page 7
4.4. Mount Power and TEC Control
•Locate the included power supply module and the supplied line cord.
Install the line cord into the power supply and plug into an appropriate
wall socket.
•Plug the power supply output plug into the LDM9T power input
receptacle located on the side of the unit.
•Power the mount using the slide switch located on the top of the unit.
The fan should immediately turn on and the Power LED should light.
•As soon as the unit is powered on the temperature will start stabilizing
to the setpoint determined by the “TEMP ADJ” knob. Allow a couple of
minutes for the temperature to stabilize whenever the unit is powered up
or the laser diode average power level is changed.
•To adjust the temperature setpoint simply adjust the Temp Adj knob
located on the top of the mount.
4.5. Thorlabs LDC Series Laser Controller Connection
•The LDM9T is compatible with all Thorlabs LDC laser diode controllers.
Thorlabs’ ITC series combination controllers (LD and TEC) may also be
used however the TEC control provided will not be used. It may be
necessary to adjust the protection settings to allow operation without the
TEC protection provided by the ITC. Appropriate cables are included
with our controllers and ensure that the controllers cannot be connected
incorrectly.
•The nomenclature for the Laser Diode polarity switch on the LDC40xx
and ITC40xx drivers and the LDM9T are consistent with each other. For
example, if the laser polarity on the driver is set to “AG” (anode
grounded), then the LD polarity switch on the LDM9T should also be set
to AG.
•The nomenclature for the Photo Diode polarity switch on the
LDC40xx/80xx and ITC series drivers and the LDM9T is as follows: The
photodiode polarity switch on the LDM9T must always be set to “CG”.
The photodiode polarity should be set with the internal Laser controller
switch only. For more information on how to set Polarity settings on the
Laser controller, please refer to the appropriate Laser Controller
manual.
Note: The LDC and ITC series controllers can be used to monitor the photodiode
current “IPD”. If the sign of the photodiode current “IPD” is negative, the photodiode
is reversed. Please double check the laser diode pin configuration and polarity
switches before turning on the unit.

LDM9T Chapter 4: Setup
Page 8 15827-D02
4.6. Using a Third-Party Laser Controller
When using a third-party controller, a custom cable will have to be made to
properly interface to the laser mount. Please refer to the table below for laser
connections.
Figure 4 LD Controller DB9 Connection
Pin
Signal
Description
1
Interlock and
Status Pin
(LDC Specific)
This pin is the input to the LD Status indicator and interlock
circuits. When using Thorlabs’ LDC controllers, no external
circuitry is required.
2
Photodiode
Cathode
This pin is connected to the 12 o’clock pin on the laser
socket when the PD polarity switch is set to AG (anode
grounded). It is attached to ground and the 9 o’clock and 3
o’clock pins on the laser socket when the PD polarity switch
is set to CG (cathode grounded).
3
Laser Ground
(Case)
This pin is connected to the 9 o’clock and 3 o’clock pins on
the laser socket and corresponds to the settings of the LD
and PD polarity switches. i.e., If the LD and PD switches are
set to AG, then this pin grounds the anode of the laser diode
and photodiode.
4
Photodiode
Anode
This pin is connected to the 12 o’clock pin on the laser
socket when the PD polarity switch is set to CG (cathode
grounded). It is attached to ground and the 9 o’clock and 3
o’clock pins on the laser socket when the PD polarity switch
is set to AG (anode grounded).
5
Interlock and
Status Return
This pin is the return side of the Status and Interlock
circuitry.
7
Laser Diode
Cathode
This pin is connected to the 6 o’clock pin on the laser socket
when the LD polarity switch is set to AG (anode ground).
Otherwise it is floating.
8
Laser Diode
Anode
This pin is connected to the 6 o’clock pin on the laser socket
when the LD polarity switch is set to CG (cathode ground).
Otherwise it is floating.
6, 9
NC
These pins are typically used to monitor LD voltage when
used with the Thorlabs LDC series controllers. This mount
does not support this feature.