THORLABS GSL Series Gain Switched Lasers User Guide

THORLABS GSL Series Gain Switched Lasers

Product Information

Specifications

• Model Options: GSL45A, GSL49A, GSL52A, GSL63A, GSL85A, GSL106A, GSL131A, GSL155A
• Typical Center Wavelength: Varies based on model
• Picosecond Pulse Width: 37 mW (for example)
• Typical Peak Power (ns Operation): Varies based on model
• Repetition Rates: 1, 10, 100, and 200MHz

Product Usage Instructions

Chapter 3: Installation
Follow the guidelines provided in the installation section of the manual to set up the GSL Series Gain-Switched Laser correctly.

Chapter 4: Operation

1. Connect the laser to a power source using the power jack on the back panel.
2. Use the controls on the back panel to adjust pulse width and repetition rate according to your requirements.
3. Ensure proper connections using shielded cables for inputs and outputs.

Chapter 5: Specifications
Refer to the specifications section above for model options, wavelength, pulse width, peak power, and repetition rates available for the GSL Series Gain-Switched Lasers.

FAQ

• Is the GSL Series Gain-Switched Laser water-resistant?
  No, the GSL Series Gain-Switched Laser is not water-resistant. Avoid exposing it to liquid spills or moisture to prevent damage.

• How can I adjust the pulse width and repetition rate of the laser?
  The back panel of each laser provides controls for adjusting the pulse width and repetition rate. Refer to the user manual for detailed instructions on using these controls.

Introduction

The GSL series of lasers provide picosecond, nanosecond, and continuous wave operation in a compact, fiber-coupled, turnkey source. Gain-switched pulse generation with repetition rate control up to 200 MHz and adjustable pulse widths allow for applications including high-speed imaging and fluorescence lifetime measurements. They also make these lasers ideal seed sources for additional amplification. Single-mode fiber output through an FC/APC connector allows for integration with a range of fiber-terminated devices.

Series Overview
Model options are summarized in the table below.

Item #

| Typical Center Wavelength| Picosecond Pulse Width| Nanosecond Pulse Width| Typ. Max Peak Power

(ps Operation)

| Typ. Peak Power (ns Operation)
---|---|---|---|---|---
GSL45A| 450 nm ± 10 nm| <90 ps| 1 to 65 ns| >32 mW| 12 mW
GSL49A| 488 nm ± 10 nm| <120 ps| 1 to 65 ns| >29 mW| 12 mW
GSL52A| 520 nm ± 10 nm| <120 ps| 1 to 65 ns| >40 mW| 15 mW
GSL63A| 633 nm ± 10 nm| <130 ps| 1 to 65 ns| >75 mW| 35 mW
GSL85A| 850 nm ± 10 nm| <70 ps| 1 to 65 ns| >86 mW| 37.5 mW
GSL106A| 1064 nm ± 10 nm| <100 ps| 1 to 65 ns| >35 mW| 25 mW
GSL131A| 1310 nm ± 20 nm| <80 ps| 2 to 65 ns| >43 mW| 37.5 mW
GSL155A| 1550 nm ± 20 nm| <80 ps| 2 to 65 ns| >37 mW| 30 mW

Inputs and Controls
The back panel of each laser provides controls for the pulse width and repetition rate, as well as an SMA connector for trigger input and output signals. Available internally generated repetition rates are 1, 10, 100, and 200 MHz.

Safety Information

All statements regarding safety of operation and technical data in this instruction manual will only apply when the unit is operated correctly. If equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired. Only with written consent from Thorlabs may changes to single components be carried out or components not supplied by Thorlabs be used.

Warnings and Cautions

• Warning: Laser Radiation
  • Avoid Exposure – Radiation emitted from apertures. Do not look into the laser aperture while the laser is on. Injury to the eye may result. Laser should not be turned on unless there is an optical fiber connected to the laser output port.
  • Caution – Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.

• Caution: ESD Sensitive Component
  The components inside this instrument are ESD sensitive. Take all appropriate precautions to discharge personnel and equipment before making any connections to the unit.

• Caution: Components not Water Resistant
  This instrument should be kept clear of environments where liquid spills or condensing moisture are likely. It is not water resistant. To avoid damage to the instrument, do not expose it to spray, liquids, or solvents.

• Caution: Follow Intended Usage Guidelines

  • Inputs and outputs must only be connected with shielded connection cables.
  • The safety of any system incorporating the equipment is the responsibility of the assembler of the system. If equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired. Only with written consent from Thorlabs may changes to single components be carried out or components not supplied by Thorlabs be used. There are no user serviceable components inside this device.

Precautions
The following statement applies to the products covered in this manual, unless otherwise specified herein. The statement for other products will appear in the accompanying documentation.
Note: This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules, and meets all requirements of the Canadian Interference Causing Equipment Standard ICES-003 for digital apparatus. These limits are designed to provide reasonable protection against harmful interference in an industrial installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. Thorlabs is not responsible for any radio television interference caused by modifications of this equipment or the substitution or attachment of connecting cables and equipment other than those specified by Thorlabs. The correction of interference caused by such unauthorized modification, substitution or attachment will be the responsibility of the user. The use of shielded I/O cables is required when connecting this equipment to all optional peripherals or host devices. Failure to do so may violate FCC and ICES rules.

Installation

Quick Start Guide

1. Connect the power supply cable to the laser head and then plug the power supply into mains power.
2. Make sure the interlock pin is in place at this time. An external interlock circuit can be added later for more convenient integration of the interlock safety feature.
3. Connect the patch cable with FC/APC connector to the laser output mating sleeve.
4. Put laser safety goggles on if your situation requires them.
5.  Turn the power switch on using the key switch.
6. The multicolored status LED indicator (red/green/amber) will blink until the laser temperature has stabilized. Initial warm up can take 30 – 60 seconds. The multicolored laser emission LED (red/blue) will then glow continuously when the laser output is enabled. Note that there is a four second delay between the time the emission indicator glows solid and laser output is enabled.
   Note: For repetition rate setting “A” and “B” there will be no optical output unless the laser is triggered.

Packaging List

• GSL Series Laser Head
• Precision Patch Cable, 1 m Long with Ø2 mm Jacket (Item #s GSL45A, GSL49A, GSL52A, GSL63A, GSL85A, GSL106A)
• DS15 +15 V Power Supply
• 2.5 mm Flathead Screwdriver

Operation

Block Diagram

• The block diagram in Figure 3 depicts the internal architecture of the laser head, which contains all of the pulsing drive electronics, safety interlocks, trigger circuits, and the temperature stabilization system. The multicolored LED indicators are designed to be visible through most laser safety glasses. The Status LED blinks during the 30 – 60 s warm up and then turns off once temperature stability is achieved. Additional Status LED indications are summarized in Section 4.6. The Emission LED is active four seconds before laser emission and stays active in any state where laser emission is possible.
• In addition to external triggering with both high impedance (Hi-Z) and 50 Ω termination there are also four different internally generated repetition rates: 1, 10, 100, and 200 MHz.

Power

• Power is supplied by the external, +15 V, wall-mounted DS15 Power Supply included with the unit and shown in the left image of Figure 4. The power supply includes a region-specific plug. The mini-XLR type connector, which uses a latching mechanism to prevent accidental pull-out, plugs into the laser head as shown in the right image of Figure 4.

• The key switch controls power to all internal components. When the key switch is turned on, the temperature stabilization system is activated. There is a 30 – 60 second warm up, during which time the LED indicator light blinks. When the LED stops blinking, there is an additional four second delay and then laser is enabled. Note there will not be any optical output until the interlock is satisfied, a trigger signal is supplied, and the pulse width and repetition rate combination are in an allowed state as show in the table in Section 4.5.

Interlock Circuit

• The laser is equipped with a phono-type interlock jack located on the back panel. To enable the laser source, a short circuit must be applied across the terminals of the interlock connector. The shorting device (interlock pin) installed in all units shipped from Thorlabs performs this function. Leave the shorting device installed unless using an external safety circuit or other type of remotely controlled switch to enable laser output.
• Making use of the Interlock feature requires the appropriate 2.5 mm phono-type plug, which is shown in the left diagram of Figure 5 and is readily available through most electronics retailers. The plug should be wired to the external safety circuit or switch and then plugged into the back panel’s interlock jack in place of the shorting device. The electrical specifications of the interlock jack are listed in the following table, and the circuit schematic describing how the interlock jack is connected inside the laser head is shown in the right diagram of Figure 5.
  Parameter| Specification
  ---|---
  Interlock Switch Requirements| Must be Normally Open Dry Contacts, Apply no External Voltages to the Interlock Input
  Type of Mating Connector| 2.5 mm Mono Phono Jack
  Open Circuit Voltage| 5 VDC

(Center Pin is at 5 VDC, Ring is Ground)

• The user’s safety circuit must be attached to the phono plug and wired such that the ring and center pin are shorted when it is safe to enable the laser. The laser will be enabled when connection is closed. If it changes to an open state, the laser source will turn off.

Repetition Rates and Pulse Widths

• The GSL series of lasers has four internally triggered repetition rates and two externally triggered settings accommodating both Hi-Z and 50 Ω impedance. The internally available rates include: 1, 10, 100 and 200 MHz. Use the included 2.5 mm flathead screwdriver to operate these controls.
• All of the GSL series offers controls for varying the pulse width. Use the included 2.5 mm flathead screwdriver to operate this control also, as shown in Figure 6. The range of pulse widths for each model are listed in the specifications table in Section 5.1. The pulse width control directly programs the pulse generator and has 16 positions, which allows the pulse width to be adjusted to the settings shown in the table in Section 4.5. Plots of typical pulses and of typical pulse width as a function of control setting are available in the web presentation.

Trigger Port
The Trigger In/Out port has dual function. If the internal oscillators are used, then the Trigger port provides an output signal that is synchronized with the pulse generation. Both a Hi-Z and 50 Ω user-trigger mode are available for low-frequency and high-frequency operation respectively. In the user-triggered mode, the SMA port allows external trigger signals to drive the pulse generator. See the Specifications table in Section 5.2 for the correct signal levels and impedances. Allowable repetition rate ranges for each pulse duration are given in the table below.

Pulse Width Position| Pulse Width| Max Rep. Rate| Min Rep. Rate
---|---|---|---
1 – MIN| <130 psa| 200 MHz| 200 kHz
2| 1 – 2 ns| 200 MHz| 200 kHz
3| 3 – 4 ns| 100 MHz| 200 kHz
4| 6 ns| 30 MHz| Single Shot
5| 8 ns| 30 MHz| Single Shot
6| 10 ns| 30 MHz| Single Shot
7| 12 ns| 30 MHz| Single Shot
8| 14 ns| 30 MHz| Single Shot
9| 16 ns| 30 MHz| Single Shot
10| 18 ns| 25 MHz| Single Shot
11| 20 ns| 20 MHz| Single Shot
12| 25 ns| 16 MHz| Single Shot
13| 30 ns| 13 MHz| Single Shot
14| 40 ns| 10 MHz| Single Shot
15 – MAX| 65 ns| 5 MHz| Single Shot
16 – CW| CW| N/A| N/A

Status LED
The operational state of the GSL series of lasers is indicated through the multicolor (Red/Green/Amber) “STATUS” LED on the back panel of the laser. Following typical thermal stabilization and laser emission delay, this LED should be OFF (-). A full list of the states is summarized in the following table.

Laser State

| Status LED State
---|---
Red| Green| Amber
Laser Emission| –| –| –
Error| Blinking a| –| –
Interlock OPEN| On| –| –
Rep. Rate Out of Range| –| –| Slow Blinking
Laser Powering On| –| Slow Blinking| –

Specifications

Optical Specifications

@ 633 nmb

Laser Class| 3B| 3B| 3B| 3B
Picosecond Pulse Operation
Average Power c| >0.6 mW| >0.7 mW| >1.0 mW| >2.0 mW
Pulse Duration d| <90 ps| <120 ps| <120 ps| <130 ps
Spectral Linewidth| <3 nm| <4 nm| <6 nm| <3 nm
Repetition Rates| 200 kHz to 200 MHz
Peak Power (Typ. Max)| >32 mW| >29 mW| >40 mW| >75 mW
Power Stability e| <2%
Nanosecond Pulse Operation
Pulse Durations d| 1 – 65 ns
Repetition Rates f| See Section 4.5
Peak Power (Typical)| 12 mW| 12 mW| 15 mW| 35 mW
CW Operation
Average Power| 3 mW| 5 mW| 5 mW| 15 mW
Item #| GSL85A| GSL106A| GSL131A| GSL155A
---|---|---|---|---
Center Wavelength| 850 ± 10 nm| 1064 ± 10 nm| 1310 ± 20 nm| 1550 ± 20 nm
Fiber Type a| 780HP| HI1060| SMF-28 Ultra| SMF-28 Ultra
Fiber Mode-Field Diameter| 5.0 ± 0.5 µm

@ 850 nm

| 6.2 ± 0.3 µm

@ 1060 nm

| 9.2 ± 0.4 µm

@ 1310 nm

| 10.4 ± 0.5 µm @ 1550 nm
Laser Class| 3B| 3B| 1M| 1M
Picosecond Pulse Operation
Average Power b| >1.2 mW| >0.7 mW| >0.7 mW| >0.6 mW
Pulse Duration c| <70 ps| <100 ps| <80 ps| <80 ps
Spectral Linewidth| <5 nm| <15 nm| <12 nm| <20 nm
Repetition Rates| 200 kHz to 200 MHz
Peak Power (Typ. Max)| >86 mW| >35 mW| >43 mW| >37 mW
Power Stability d| <2%
Nanosecond Pulse Operation
Pulse Durations c| 1 – 65 ns| 2 – 65 ns
Repetition Rates e| See Section 4.5
Peak Power (Typical)| 37.5 mW| 25 mW| 37.5 mW| 30 mW
CW Operation
Average Power| 20 mW

Trigger Specifications

Input Voltage b

| 50 Ω (AC Coupled)c| 0.2 – 5.0 Vpp

Hi-Z, 5 kΩ (DC Coupled)

| VIL| 0 – 0.8 V
VIH| 2.2 – 5 V

Output Voltage

| 50 Ω| 400 mV
Hi-Z| 800 mV
Max Timing Jitter d| 12 ps RMS
Delay from External Trigger Input to Optical Output e| 44 ± 4 ns
Delay from Internal Trigger to Optical Output e| 3.4 ± 1.5 ns

Power, Environmental, and Physical Specifications

1.55″)

Mechanical Drawings

Maintenance and Troubleshooting

Maintenance

• The GSL laser should not require regular maintenance. If necessary, the housing can be cleaned using a soft cloth moistened with a mild glass cleaner. Do not use acetone, chemical solvents, or harsh cleaning solutions, and do not spray cleaning solutions directly onto the unit. See Section 7.3 for advice on fiber cleaning.
• Aside from the procedure outlined in Section 7.3, there are no user serviceable components in GSL series lasers. If malfunctions occur, please contact Thorlabs’ technical support ([email protected]). Do not disassemble the unit.
• See the troubleshooting guide below for basic help.

Troubleshooting

No Output

| Check that power is supplied and connected properly. Check that key switch is turned on.

Confirm that laser is warmed up (30 – 60 s). Confirm the interlock circuit is complete.

Check that the indicator LED is glowing continuously.

Check that a trigger signal is being provided for REP RATE position “A” and “B”.

Power is Low| Check to see if the fiber end face is dirty.

If so, see the cleaning instructions in section 7.3.

Status LED Blinking Amber| Internal or externally provided repetition rate is out of range for pulse width. Check that the repetition rate falls into the allowable range provided in section 4.5.

Status LED Blinking Red

| Temperature control or communications error.

Check that the unit is being operated within the ambient temperature range. Contact Tech Support to assist with this error.

Fiber Inspection and Cleaning
Should an issue arise with low output power or a distorted beam out of the laser, please follow these instructions to inspect and clean the end face of the fiber.

1. Turn off the power to the unit and disconnect the power supply.
2. Using a 1.3 mm hex wrench, remove the mating sleeve at the laser output (Figure 8).
3. Pull out the mating sleeve to give access to the fiber connector. Take care not to pull out more than 10 cm of fiber to allow for inspection and cleaning with fiber cleaner.
4. Once the endface has been inspected and/or cleaned, replace the mating sleeve and test for performance.

Declaration of Conformity

Thorlabs Worldwide Contacts

For technical support or sales inquiries, please visit us at www.thorlabs.com/contact for our most up- to-date contact information.

• USA, Canada, and South America
  • Thorlabs, Inc.
  • [email protected]
  • [email protected]
• Europe
  • Thorlabs GmbH
  • [email protected]
• France
  • Thorlabs SAS
  • [email protected]
• Japan
  • Thorlabs Japan, Inc.
  • [email protected]
• UK and Ireland
  • Thorlabs Ltd.
  • [email protected]
  • [email protected]
• Scandinavia
  • Thorlabs Sweden AB
  • [email protected]
• Brazil
  • Thorlabs Vendas de Fotônicos Ltda.
  • [email protected]
• China
  • Thorlabs China
  • [email protected]

References

• Thorlabs, Inc. - Your Source for Fiber Optics, Laser Diodes, Optical Instrumentation and Polarization Measurement & Control
• Thorlabs, Inc. - Your Source for Fiber Optics, Laser Diodes, Optical Instrumentation and Polarization Measurement & Control

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