THORLABS LDM405 User manual

LDM405, LDM635, LDM670,
LDM785, LDM850, LDM1550
Laser Diode Modules
User Guide

LDM Series Laser Diode Modules
Table of Contents
Chapter 1Warning Symbol Definitions ...........................................1
Chapter 2Safety.................................................................................2
2.1.LaserSafety...................................................................3
Chapter 3Description........................................................................4
Chapter 4Operation...........................................................................5
4.1.NormalOperationandUse............................................5
4.2.MakingtheSafetyInterlockConnections.......................7
Chapter 5Specifications ...................................................................8
5.1.Drawing.........................................................................9
Chapter 6Declaration of Conformity .............................................10
Chapter 7Regulatory.......................................................................11
Chapter 8Thorlabs Worldwide Contacts.......................................12

LDM Series Laser Diode Modules Chapter 1: Warning Symbol Definitions
Page 1 Rev G, September 18, 2017
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

LDM Series Laser Diode Modules Chapter 2: Safety
11837-D02 Page 2
Chapter 2 Safety
Precautions of a general nature should be gathered here. Wherever possible,
however, safety warnings, cautions, and notes should only appear immediately
before the instructions to which they apply (versus being listed in this section).
WARNING
This unit must not be operated in explosive environments. Do not operate in wet
or damp conditions. Do not obstruct the air-ventilation slots in the housing!
WARNING
Avoid Exposure – Laser Radiation Emitted from apertures.
WARNING
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.
This device can only be returned when packed into the complete original
packaging, including all packing inserts. If necessary, ask for a replacement
package.
The maximum USB and BNC cable length is 3 meters in order to avoid a
susceptibility to RF interference according to IEC61000-4-3.
Note: If equipment is used in a manner not specified by the manufacturer, the
protection provided by the equipment may be impaired.
Complies with 21 CFR 1040.10 and 1040.11 except for deviations pursuant to
laser notice no. 50, dated 5/27/01.
!
!
!!

LDM Series Laser Diode Modules Chapter 2: Safety
Page 3 Rev G, September 18, 2017
2.1. Laser Safety
The LDM series of lasers are rated in the 1, 3R, and 3B Laser Safety Class.
According to Laser Institute of America: A Class 3B laser is hazardous if the eye
is exposed directly, but diffuse reflection such as from paper or other matte
surfaces are not harmful. Class 3R levels of laser radiation are considered to be,
depending upon the irradiance, either an acute intrabeam viewing hazard or
chronic viewing hazard, and an acute viewing hazard if viewed directly with optical
instruments. Class 1 lasers are very low risk and "safe under reasonably
foreseeable use". Protective eyewear is typically required where direct viewing of
a class 3R and 3B laser beam may occur. Class 3B lasers must be equipped with
a key switch and a safety interlock.
According to the revised ANSI Z136.1 Safe Use of Lasers, laser area warning
signs should be posted around Class 3 laser areas and are required to be posted
around all Class 3B and 4 laser areas. NOTICE signs are required for Class 3B
and Class 4 lasers during maintenance, servicing, and similar situations.
LASER RADIATION
CLASS 1 LASER PRODUCT
1520 - 1580 nm <5 mW
LASER RADIATION
AVOID DIRECT EYE EXPOSURE
CLASS 3R LASER PRODUCT
395 – 650 nm <5 mW
LASER RADIATION
AVOID EXPOSURE TO THE BEAM
CLASS 3B LASER PRODUCT
650 – 860 nm <5 mW

LDM Series Laser Diode Modules Chapter 3: Description
11837-D02 Page 4
Chapter 3 Description
The LDM Series of compact laser sources are well suited to benchtop optical
experiments. The LDM Series modules come in six wavelength versions: 405, 635,
670, 785, 850, and 1550 nm. The Ø1.40" by 5.8" housing contains a laser diode,
collimating lens, and automatic power control circuit.
Each LDM module includes a built in shutter and SM1 internal thread for mounting
with an extensive range of opt mechanical devices from lens tubes to lens mounts.
The LDM module can easily be mounted to any optical table using one of our
C1502, C1503, or VC3 V-groove mounts.
Besides the mechanical shutter, the module also features a remote interlock
connection and key-lock power switch. The laser module has an enable/disable
toggle switch, laser on indicator LED, and power adjustment pot on the top for easy
access. The power can be adjusted from 0 to full power (laser specific, see the
specifications section for more information).

LDM Series Laser Diode Modules Chapter 4: Operation
Page 5 Rev G, September 18, 2017
Chapter 4 Operation
CAUTION!
Always observe proper Laser safety when operating this unit.
4.1. Normal Operation and Use
The unit should be located on a solid, dry working surface. If preferred, the unit
can be secured to a standard optical breadboard using Thorlabs C1502, C1503,
or VC3 V-groove mounts. For best performance, the unit should be oriented with
its vent holes and cooling slots facing up.
1. If not already done, move the output shutter lever to the CLOSED position.
Figure 1 Front View of LDM
2. With the key-lock switch set to the 0 (Off) position, connect the power supply
to the LDM by plugging the DC Jack into the DC IN socket on the end cap
of the module. Plug the AC connector of the power supply into a suitable
mains socket.
3. Make sure the interlock shorting screw is in place. If using a remote
interlock, see the next section for instructions on how to set up the remote
interlock.
Shutter Control
Knob
Laser Aperture

LDM Series Laser Diode Modules Chapter 4: Operation
11837-D02 Page 6
4. Turn the key-lock switch to the l (ON) position. The green LED will blink
slowly.
Figure 2 Rear Control View of LDM
5. Momentarily press the Enable switch. The green LED will blink more quickly
for approximately 5 seconds and then remain on solid. At that point the laser
will turn on.
6. Open the output shutter by moving the shutter lever to the OPEN position.
7. The output power can be adjusted from roughly the laser threshold current
to the full output power of the laser module by turning the PWR ADJ screw
using a small screwdriver. Clockwise rotation increases the output power.
Figure 3 Top View, Close Up of Controls
8. Pressing the Enable switch will turn off the laser.
9. Turning the Key-lock switch to the 0 (Off) position will also turn off the laser
output. The enable button will need to be pressed to enable the laser after
the Key-lock is returned to the l (ON) position.
10. Disconnecting the Interlock pin will also turn off the laser.
DC power
supply in
Key-lock switch currently
in the off position
Interlock control
with shorting
device
Power adjustment pot
(recessed to prevent
accidental changes)
Laser Enabled
Indicator LED
Enable/disable toggle
switch

LDM Series Laser Diode Modules Chapter 4: Operation
Page 7 Rev G, September 18, 2017
4.2. Making the Safety Interlock Connections
The LDM Series is equipped with a remote interlock connector located on the end
cap. In order to enable the laser driver, 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 shutdown.
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 your remote interlock
switch. Next, remove the shorting device by unscrewing it from the output and
install the connector into the Interlock output.
The Interlock output only accepts a 2.5 mm mono phono jack. This connector is
readily available at most electronic supply stores.
The electrical specifications for the Interlock output are as follows:
Type of Mating Connector: 2.5 mm mono phono jack
Connector Polarity: Tip is positive, barrel is ground
Interlock Switch Requirements: Must be N.O. dry contacts
Figure 4 Remote Interlock Connector
CAUTION!
Under no circumstances should any external voltages be applied to the
Interlock output

LDM Series Laser Diode Modules Chapter 5: Specifications
11837-D02 Page 8
Chapter 5 Specifications
Item # LDM405 LDM635 LDM670
Wavelength, Typical 405 nm 635 nm 670 nm
Wavelength, Min/Max 395 - 415 nm 625 - 645 nm 660 - 678 nm
Beam Diametera3.0 mm x 5.0 mm 3.0 mm x 5.0 mm 3.2 mm x 3.4 mm
Power, Adjustableb4.0 mW 4.0 mW 5.5 mW
Item # LDM785 LDM850 LDM1550
Wavelength, Typical 785 nm 850 nm 1550 nm
Wavelength, Min/Max 776 - 800 nm 840 - 860 nm 1520 - 1580 nm
Beam Diametera 2.4 mm x 3.4 mm 3.5 mm x 4.4 mm 2.6 mm x 3.0 mm
Power, Adjustableb20 mW 20 mW 4.5 mW
Common Specifications
Stability, Short Term Drift (30 min) 0.01 dB
Stability, Long Term Drift (24 hrs) 0.1 dB
Operating Temperature 10 to 40 °C
Storage Temperature 5 to 50 °C
Power Supply @ ±10% (Included)
100 – 240 VAC, 0.48 A
50 – 60 Hz
Output: 9 VDC @ 2.2 A
aMeasured 3 m from module. Beam shape is elliptical
bThe maximum power is given for an operating temperature of 25 °C. When operated at a temperature
other than this, the maximum output will vary.