THORLABS LDM9LP User manual

LDM9LP
Pigtailed Laser Mount
Operating Manual

Pigtailed Laser Mount
Table of Contents
Warning Symbol Definitions ...........................................1
Safety.................................................................................2
Description........................................................................ 3
Setup.................................................................................. 5
4.1.General..........................................................................5
4.2.SpecialNotefor4‐pinLaserDiodes..............................10
4.3.SpecialNoteforLaserDiodeswithoutaMonitor
Photodiode..................................................................11
4.4.LaserDiodeCurrentControllerConnection...................11
4.5.UsingaThird‐PartyLaserController.............................12
4.6.TECControllerConnection............................................13
4.7.TECLockoutandGroundJumpers................................14
Operation.........................................................................15
5.1.General........................................................................15
5.2.RFModulation.............................................................15
5.3.StatusandInterlocks...................................................16
5.4.MaintainingtheLDM9LP.............................................16
Making Safety Interlock Connections .......................... 17
Troubleshooting .............................................................18
Specifications .................................................................19
8.1.RFModulationCharts..................................................20
8.2.ThermistorData..........................................................22
Mechanical Drawing.......................................................23
Regulatory.......................................................................24
Thorlabs Worldwide Contacts.......................................25

Pigtailed Laser Mount Chapter 1: Warning Symbol Definitions
Rev C, September 5, 2018 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

Pigtailed Laser Mount Chapter 2: Safety
Page 2 TTN027954-D02
Safety
WARNING
This unit must not be operated in explosive
environments
WARNING
Avoid Exposure – Laser Radiation Emitted from
apertures
WARNING
Observe ESD Handling Precautions

Pigtailed Laser Mount Chapter 3: Description
Rev C, September 5, 2018 Page 3
Description
Designed for Thorlabs' Ø5.6 mm (TO-56) and Ø9 mm (TO-9) Pigtailed
Laser Diodes, Single Mode, Polarization Maintaining, or Multimode
TEC Element Prolongs LD Life and Stabilizes Output Power and
Wavelength
Clamshell Design Eliminates Thermal Gradients Across Diode
Bias-T Adapter for RF Modulation of Laser Current >200 kHz
Thorlabs' LDM9LP is an LD and TEC mount designed for use with all of our 3-
and 4-pin pigtailed diodes
1
. The compact housing protects the pigtail from
physical damage, while also offering excellent thermal characteristics. Two 1/4"
through holes can be used for securing the mount to an optical table with 1/4"-20
or M6 cap screws.
When operating a pigtailed laser diode, temperature control is highly
recommended to stabilize the laser's power and wavelength, while also
prolonging the life of the laser. Typical laser diode mounts rely on contact
between the diode and the mount's cold plate for heat transfer. Pigtailed laser
diodes are often recessed in the pigtail's housing, offering poor contact with the
cold plate of standard laser diode mounts. The LDM9LP, however, is specifically
designed for operating pigtailed laser diodes. Its clamshell design reduces
thermal gradients across the diode, while its cold block cradles the pigtail
housing for excellent contact and heat transfer.
DB9 connections interface with all of Thorlabs' LD Current Controllers and TEC
Controllers. An SMA connector allows access to a Bias-T circuit for RF
modulation of the laser's drive current (200 kHz to >1 GHz). For modulation
below 200 kHz, current should be modulated through the laser diode controller. A
remote interlock jack is provided for the connection of safety devices such as
shutters and warning signs.
1 Due to the variety of fiber pigtailed laser diode packages offered by other companies, this mount is
only designed for use with Thorlabs products. Thorlabs offers a laser diode pigtailing service; please
contact Tech Support for details.

Pigtailed Laser Mount Chapter 3: Description
Page 4 TTN027954-D02
LDM9LP Contents:
Pigtail Mount
1.5mm Hex Key
Operating Manual
Supported Pin Style
Style A
Case
LD PD LD PD LD PD
LD PD
Case Case
Case
Style B Style C
Style D
LD
Case
Style E
LD
Case
Style H
Supported Pin Configurations
LD
Case
Style G

Pigtailed Laser Mount Chapter 4: Setup
Rev C, September 5, 2018 Page 5
Setup
4.1. General
1. Remove the two M2 screws, from the protection cover and remove the
cover.
2. Remove the four M2 screws, that fix the upper cooler shell, and remove the
upper shell.
3. Remove the two M2 screws fixing the laser mounting plate to the cooler and
pull out the plate from the connector.

Pigtailed Laser Mount Chapter 4: Setup
Page 6 TTN027954-D02
4. Determine the laser pin config-uration from the laser diode data sheets and
install the Laser Diode into the socket as shown, according to the corresponding
Pin Code. Refer to Figure 4 on page 9.
5. The STYLE jumper on the back of the laser mounting PCB should be placed
according to the particular LD pin configuration being used. For pin codes A, B,
C, D, E, or H, set the STYLE jumper to the lower two pins. For pin code G, set
the jumper to the upper two pins.
6. The BYPASS jumper should be set only if the laser is modulated via the LD
DRIVER input on the LDM9LP. Please refer to the table below.
Operation Mode Bypass Jumper
Low noise, no modulation No (Removed)
RF Modulation via RF IN (BIAS-T) No (Removed)
Modulation via LD DRIVER input2Yes (Set)
2
If the LD driver being used has a noise reduction filter feature, the jumper may need to be removed to
ensure good performance.

Pigtailed Laser Mount Chapter 4: Setup
Rev C, September 5, 2018 Page 7
7. Based on the pin configuration used, set the LD and PD switches on the side of
the LDM9LP according to the diagram below.
Polarity Switch Settings
Style A
Case
LD PD
LD PD
LD PD
LD
Case
Case
Case
Style B
LD PD
Case
Style C
LD
Case
Style G
Style D
Style E
LD
Case
Style H
LD
LD
LD
PD
LD
LD
AG
CG AGCG AG
CG AG CG
AG
CG AG CG
AG
CG AG CG
AG
CG AGCG
AG
CG AGCG
LD
PD
PD
PD
PD
N/A
PD
N/A
Switch Position
(Black Square)
LD
AG
CG AG
CG
PD
N/A

Pigtailed Laser Mount Chapter 4: Setup
Page 8 TTN027954-D02
8. Thread the two M2 socket head screws into the pigtail flange, securing it to
the mounting flange. Next, replace the upper cooler shell and tighten the
four M2 socket head screws. Lastly, reattach the protective cover using two
M2 socket head screws.
Laser Diode Socket

Pigtailed Laser Mount Chapter 4: Setup
Rev C, September 5, 2018 Page 9
Socket Diagram
Note: 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 LDM9LP was designed to operate the laser case
at ground potential, therefore this common pin will be inserted into either of the
holes marked ‘G’ below. Insert the isolated laser pin in the position marked LD.
The isolated photodiode should now be in the position marked PD.
Socket Pin Diagram
GND
LD LD
PD
PD
GND
LD
GND
GND GND
LD
Cathode
PD
Anode
GND
LD
LD
GND GND
LD
Cathode
GND
LD
PD
GND
LD
PD
GND
LD
GND
GND GND
LD
Anode
PD
Pin Code A Pin Code D Pin Code EStyle: A, D, E
Pin Code GStyle: G
Pin Code B Pin Code C Pin Code HStyle: B, C, H
Socket Pin Diagram
Set by Jumper Style
Laser Diode Pin Diagrams - Bottom View
(Bold Dots Indicate Case Connection)

Pigtailed Laser Mount Chapter 4: Setup
Page 10 TTN027954-D02
4.2. Special Note for 4-pin Laser Diodes
The LDM9LP also supports 4-pin laser diodes. Insert the laser into the 4-pin
socket and note which laser pin is in the 12 o’clock position (laser anode or
cathode). Also, note which photodiode pin is in the 6 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 above. Set the LD and PD polarity switches accordingly.
Laser diodes with pin style F are not compatible with this mount. The pins are
oriented across from each other and will not align properly in the mount.
Pin Style F
LD
PD
Case

Pigtailed Laser Mount Chapter 4: Setup
Rev C, September 5, 2018 Page 11
4.3. Special Note for Laser Diodes without a Monitor
Photodiode
Laser diodes without a monitor photodiode will also work with the LDM9LP. 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 similar to typical laser diodes with photodiodes.
4.4. Laser Diode Current Controller Connection
Using the Thorlabs LDC/ITC Series Laser Controllers:
The LDM9LP is compatible with all Thorlabs LDC LD controllers and
ITC series combination controllers (LD and TEC). Appropriate cables
with DB9 connectors are included with Thorlabs controllers and ensure
that the controllers cannot be connected incorrectly. Additionally, these
controllers have built-in protection circuitry that protects the laser when
not in use.
The nomenclature for the Laser Diode polarity switch on the LDC40xx
and ITC40xx drivers and the LDM9LP 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 LDM9LP should also be
set to AG, and so on.
The nomenclature for the Photo Diode polarity switch on the
LDC40xx/80xx and ITC series drivers and the LDM9LP is as follows:
The photodiode polarity switch on the LDM9LP 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.

Pigtailed Laser Mount Chapter 4: Setup
Page 12 TTN027954-D02
4.5. 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.
LD Controller DB9 Female Connection
LD
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. To use these features with third-party
controllers, please refer to page 16.
2 Photodiode
Cathode
This pin is connected to the 6 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 6 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.
6
Laser Diode
Voltage
(Cathode)
This pin is connected to LD interface pin 7, through a 499 
resistor, when the LD polarity switch is set to AG (anode
grounded). It is attached directly to LD interface pin 3 when
the LD polarity switch is set to CG (cathode grounded).
7 Laser Diode
Cathode
This pin is connected to the 12 o’clock pin on the laser socket
when the LD polarity switch is set to AG (anode grounded).
Otherwise it is floating.
8 Laser Diode
Anode
This pin is connected to the 12 o’clock pin on the laser socket
when the LD polarity switch is set to CG (cathode grounded).
Otherwise it is floating.
9
Laser Diode
Voltage
(Anode)
This pin is connected to LD interface pin 8, through a 499 
resistor, when the LD polarity switch is set to CG (cathode
grounded). It is attached directly to LD interface pin 3 when
the LD polarity switch is set to AG (anode grounded).
51
96

Pigtailed Laser Mount Chapter 4: Setup
Rev C, September 5, 2018 Page 13
4.6. TEC Controller Connection
Using Thorlabs’ TED Series TEC Controllers:
The LDM9LP is compatible with all Thorlabs TED series temperature
controllers and ITC series combination controllers (LD and TEC). The
TED series is shipped with a mating DB9 cable that plugs directly into
the controller and laser mount. Using the cable supplied with the TED,
the controller cannot be connected incorrectly. Simply connect the cable
included with the TED to the laser mount and to the controller.
Using a Third-Party TEC 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 connections.
TEC Controller DB9 Male Connection
TEC Pin Signal Description
1 TEC Lockout (+)
This pin is connected to the anode of the
photo-relay side of the TEC lockout
circuit. When using Thorlabs’ TED
Series, no external circuitry is required.
To use these features with third-party
controllers, please refer to the Status
and Interlock section of this manual.
2 +Thermistor The 10 k@ 25 °C NTC thermistor
(provided for temperature feedback).
3 -Thermistor The thermistor return pin.
4 +TEC This pin is connected to the positive
terminal of the TEC.
5 -TEC and TEC Lockout (-)
This pin is connected to the negative
terminal of the TEC element, and also is
common to the cathode of the photo-
relay of the TEC lockout circuit – refer to
the Status and Interlock section of this
manual.
6 NC Unused
7 NC Unused
8 NC Unused
9 NC Unused
15
69

Pigtailed Laser Mount Chapter 4: Setup
Page 14 TTN027954-D02
4.7. TEC Lockout and Ground Jumpers
Two jumpers, JMP1 and JMP2, are located under the cover on the main PCB
assembly. Remove the cover plate by removing the four M2 screws securing the
cover plate.
Locate the jumper “JMP1” on left side of the PCB. Setting or Removal the jumper
will allow you to bypass or enable the TEC Lockout feature. This feature, when
enabled, will prevent the laser diode from being turned on unless the TEC
controller is enabled. The unit is shipped from the factory with the TEC Lockout
feature bypassed.
To enable the TEC Lockout, simply remove the cover of the unit and remove the
blue jumper from the JMP1 header. The jumper can be placed on one of the
other header pins for safe keeping.
An optional ground jumper is also provided to allow connecting the system
ground node (common to the “G” pins of the laser diode connector) to the metal
housing of the unit, which is also connected to the shields of the LD and TEC
input cables. Care should be taken when using this connection as unwanted
ground loops may be formed. The unit is shipped from the factory with JMP2
disconnected. To close this connection, remove the cover of the unit and place
the blue jumper onto both pins of the JMP2 header.
Jumpers
JMP2
JMP1

Pigtailed Laser Mount Chapter 5: Operation
Rev C, September 5, 2018 Page 15
Operation
5.1. General
Once the laser is mounted in the LDM9LP and a Laser Diode Current Controller
and TEC Controller are connected, the device is ready to operate. Please refer to
the operating instructions for the laser and temperature controller for specific
operating instructions.
When operating at low temperatures in high humidity climates, the laser mount
may develop internal condensation. If this occurs, turn the laser off, open the
case, and allow the mount to dry off completely before reusing.
5.2. RF Modulation
The LDM9LP has an RF input for modulating the laser with an external RF
source from 200 kHz to beyond 1 GHz. This is a 50 input that is AC-coupled
directly to the laser through the Bias-T network. To calculate the desired RF
power to modulate the laser, determine the amount of modulating current needed
from the laser manufacturer’s data sheets and use the following calculations:
  󰇛󰇜50Ω
It is strongly recommended that you start off conservatively by a factor of 10
below the calculated modulating voltage and slowly bring the RF power up until
the desired depth of modulation is reached.
Use the laser controller to establish the DC operating point of the laser.
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.

Pigtailed Laser Mount Chapter 5: Operation
Page 16 TTN027954-D02
5.3. Status and Interlocks
This unit is equipped with two interlock circuits and an LED that indicates if the
laser diode is enabled. All three circuits are designed to interface with Thorlabs’
laser and TEC controllers with no external circuitry.
If third-party controllers are used to drive the laser diode or TEC
elements, then only the LD on indicator can be used. To prevent
damage to the Status and Interlock circuits, the following external
connections should be followed:
Install the shorting device into the REMOTE INTRLK connector that was
shipped with the LDM9LP.
Install the TEC LOCKOUT bypass jumper into JMP1 inside the LDM9LP
case (see 4.7).
Connect a resistor to LD Interface DB9 Pin 1 appropriately sized to limit
the current into Pin 1 to between 5 and 10 mA.
The “driver” side of this resistor should be connected to a DC signal
that, when high, indicates that the laser diode is being driven (driver
dependent).
If you have any questions regarding these connections, please feel free
to contact an engineer at Thorlabs for clarification.
If you wish to make full use of all of the Status and Interlock features with your
third-party drivers, please contact Thorlabs and an engineer will help you
determine if this is possible and how to implement these features.
5.4. Maintaining the LDM9LP
There are no serviceable parts in the LDM9LP. The housing may be cleaned by
wiping with a soft, damp cloth. If you suspect a problem with your LDM9LP,
please call Thorlabs and an engineer will be happy to assist you.

Pigtailed Laser Mount Chapter 6: Making Safety Interlock Connections
Rev C, September 5, 2018 Page 17
Making Safety Interlock
Connections
The LDM9LP is equipped with a Remote Interlock connector located on the side
panel. 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 diode must automatically shut down.
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 in this manual. 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 unscrewing it from
the input 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 (Radio Shack, Digikey, Mouser,
Allied, etc.).
The electrical specifications for the interlock input are as follows:
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
Remote Interlock Connector

Pigtailed Laser Mount Chapter 7: Troubleshooting
Page 18 TTN027954-D02
Troubleshooting
If you are using Thorlabs’ Laser controller with your LDM9LP:
Possible Solution Directions
Remote interlock is
open
Make sure that either the shorting device is installed in the
REMOTE INTRLK connector on the side of the LDM9LP.
If you have a remote interlock switch connected to this
REMOTE INTRLK connector, it must be in a closed
position.
Laser Driver will not
Enable
Make sure the Remote Interlock is closed. Check the laser
diode polarity and make sure the polarity switches on the
mount are set correctly.
Laser Wavelength or Power is Unstable
Possible Solution Directions
LD is not fully seated Make sure your laser pigtail is fully inserted into the
LDM9LP laser socket and its body is in full contact with
the copper cold plate.
LD is mode hopping The laser pigtail may be operating on a mode transition.
Try adjusting the temperature to shift the laser diode to a
more stable operating point.
The LDC Series Laser Driver Indicates an “Open Circuit” Alarm When You
Try to Enable the Laser
Possible Solution Directions
LD and PD polarity
switch settings are
incorrect
Refer to Figure 2 and the data sheet for your specific diode
to ensure the proper settings. The LD polarity switch
setting on the mount must match the LD polarity switch
setting on the rear panel of your LDC series laser diode
controller.
LD orientation may be
incorrect in the socket
Refer to Figure 1 and the laser pigtail data sheet for you
specific diode to ensure proper orientation.
TEC lockout circuit is
active and the TED
Series TEC controller is
not enabled
To determine if you have selected the TEC Lockout circuit
to be active, refer to 3.7 and Figure 7. If it is selected, then
the TED Series TEC controller must be enabled first
before the LDC Series laser controller can be enabled.
If you still have problems or questions regarding the operation of your LDM9LP,
please feel free to call Thorlabs and ask for Technical Support.