Quantum and Interband Cascade Lasers: Distributed Feedback, HHL Package

Webpage Features
	Clicking this icon opens a window that contains specifications and mechanical drawings.
	Clicking this icon allows you to download our standard support documentation.
Choose Item	Clicking the words "Choose Item" opens a drop-down list containing all of the in-stock lasers around the desired center wavelength. The red icon next to the serial number then allows you to download L-I-V and spectral measurements for that serial-numbered device.

Features

• Single-Wavelength Distributed Feedback Quantum or Interband Cascade Lasers (DFB QCLs and ICLs)
• High Heat Load Package Simplifies Thermal Management and System Integration
• Collimated Laser Emission Through Wedged Window
• Used in Chemical Analysis, Sensing, and IR Countermeasures
• Custom Packages and Wavelengths from 3 to 12 µm Available via Tech Support

The MIR quantum and interband cascade lasers on this webpage are offered in high heat load (HHL) packages with industry-standard pinouts and package dimensions. Each package incorporates a built-in thermistor and thermoelectric cooler (TEC) for active temperature management and prolonged laser lifetime, and also includes an internal aspheric lens that collimates the laser's output.

Distributed feedback QCLs and ICLs emit at a well defined center wavelength, making them popular for applications such as chemical sensing and sample analysis. They provide single spatial mode operation. By tuning the input current and operating temperature, the laser output can be tuned over a narrow range of at least 1 cm^-1. Before shipment, the output spectrum, optical power, and L-I-V curve are measured for each serial-numbered device by an automated test station. These measurements are available below and are also included on a data sheet with the laser.

Our ICLs emit a horizontally polarized beam at wavelengths as long as 3.5 µm, while our QCLs emit a vertically polarized beam at wavelengths as long as 11 µm. ICLs will also typically have lower voltage requirements and threshold currents, thus leading to lower optical output powers. Conversely, QCLs will consume more power and will therefore have higher output powers.

Package Details
As measured from the bottom of the package, the emission height is 12.7 ± 0.13 mm. The output beam is collimated by an AR-coated black diamond aspheric lens and then coupled out of the package through a wedged zinc sulfide (ZnS) window. This wedge prevents back reflections from returning to the laser chip, but also causes the output beam to deviate downward from the normal by -2.0° ± 1.5°, as shown in the Drawing tab of the blue info icons ( ) below. Our stocked lasers are sealed, although the seal is not hermetic; hermetically sealed versions are available by contacting Tech Support.

Each laser is electrically isolated from its mount. Heat loads for these lasers can be up to 38 W, so they must be mounted on a thermally conductive surface to prevent heat buildup. Please note that third-party cables for high heat load packages are typically not rated for the 4.5 A maximum current of the internal thermoelectric cooler. The Handling tab contains more tips and information. These QCLs and ICLs are specified for CW output. While pulsed output is possible, this application prohibits current tuning, and performance is not guaranteed. These lasers do not have built-in monitor photodiodes and therefore cannot be operated in constant power mode.

For OEM applications, Thorlabs also offers QCLs on a compact D-mount package (12.0 mm × 4.5 mm × 2.8 mm).

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Available Wavelengths for Custom DFB Lasers

DFB QCLs at Custom Wavelengths

Thorlabs manufactures custom and OEM quantum cascade lasers in high volumes. We maintain a broad chip inventory at our Jessup, Maryland laser manufacturing facility (see the graph to the left), and can deliver DFB lasers with custom center wavelengths that are qualified to a user-defined wavelength precision.

More details are available on the Custom & OEM Lasers tab. To inquire about pricing and availability, please contact us. A semiconductor specialist will contact you within 24 hours or the next business day.

Current and Temperature Controllers

Use the tables below to select a compatible controller for our MIR lasers. The first table lists the controllers with which a particular MIR laser is compatible, and the second table contains selected information on each controller. Complete information on each controller is available in its full web presentation. We particularly recommend our ITC4002QCL and ITC4005QCL controllers, which have high compliance voltages of 17 V and 20 V, respectively. Together, these drivers support the current and voltage requirements of our entire line of Mid-IR Lasers. To get L-I-V and spectral measurements of a specific, serial-numbered device, click "Choose Item" next to the part number below, then click on the Docs Icon next to the serial number of the device.

Laser and Controller Compatibility

• Please note that Thorlabs does not offer cables that connect high heat load lasers to our controllers, and that third-party cables for these packages are typically not rated for the 4.5 A maximum current of the internal thermoelectric cooler. Custom cables will be required.

Controller Selection Guide

Handling High Heat Load Lasers

Proper precautions must be taken when handling and using high heat load lasers. Otherwise, permanent damage to the device will occur. Members of our Technical Support staff are available to discuss possible operation issues.

Avoid Static
Since these lasers are sensitive to electrostatic shock, they should always be handled using standard static avoidance practices.

Avoid Dust and Other Particulates
Contamination of the window must be avoided. Do not blow on the window or expose it to smoke, dust, oils, or adhesive films. The window is particularly sensitive to dust accumulation. During standard operation, dust can burn onto it, which will lead to premature degradation of the laser performance. If operating a high heat load laser for long periods of time outside a cleanroom, it should be sealed in a container to prevent dust accumulation.

Use a Current Source Specifically Designed for Lasers
These lasers should always be used with a high-quality constant current driver specifically designed for use with lasers. Lab-grade power supplies will not provide the low current noise required for stable operation, nor will they prevent current spikes that result in immediate and permanent damage.

Thermally Regulate the Laser
Temperature regulation is required to operate the laser for any amount of time. The temperature regulation apparatus should be rated to dissipate the maximum heat load that can be drawn by the laser. For our high heat load DFB QCLs and ICLs, this value is 38 W.

The bottom face of the high heat load package is machined flat to make proper thermal contact with a heat sink. Ideally, the heat sink will be actively temperature regulated to ensure proper heat conduction. A fan may serve to move the heat away from the package and prevent thermal runaway. However, the fan should not blow air on or at the laser itself. Thermal grease, pyrolytic graphite, and water cooling methods may also be employed for temperature regulation.

For assistance in picking a suitable temperature controller for your application, please contact Tech Support.

Carefully Make Electrical Connections
When making electrical connections, care must be taken. The flux fumes created by soldering can cause laser damage, so care must be taken to avoid this.

Although soldering to the leads of our HHL lasers is possible, we generally recommend using cables specifically designed for HHL packages. Please note that third-party cables for high heat load packages are typically not rated for the 4.5 A maximum current of the internal thermoelectric cooler. If soldering to the leads on an HHL package, the maximum soldering temperature and time are 250 °C and 10 seconds, respectively.

Minimize Physical Handling
As any interaction with the package carries the risk of contamination and damage, any movement of the laser should be planned in advance and carefully carried out. It is important to avoid mechanical shocks. Dropping the laser package from any height can cause the unit to permanently fail.

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Some of Our Available Packages

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Wire Bonding a Quantum Cascade Laser on a C-Mount

Custom & OEM Quantum Cascade and Interband Cascade Lasers

At our semiconductor manufacturing facility in Jessup, Maryland, we build a wide range of mid-IR lasers and gain chips. Our engineering team performs in-house epitaxial growth, wafer fabrication, and laser packaging. We maintain chip inventory from 3 µm to 12 µm, and our vertically integrated facilities are well equipped to fulfill unique requests.

High-Power Fabry-Perot QCLs
For Fabry-Perot lasers, we can reach multi-watt output power on certain custom orders. The available power depends upon several factors, including the wavelength and the desired package.

DFB QCLs at Custom Wavelengths
For distributed feedback (DFB) lasers, we can deliver a wide range of center wavelengths with user-defined wavelength precision. Our semiconductor specialists will take your application requirements into account when discussing the options with you.

The graphs below and photos to the right illustrate some of our custom capabilities. Please visit our semiconductor manufacturing capabilities presentation to learn more.

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Available Wavelengths for Custom QCLs

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Maximum Output Power of Custom Fabry-Perot QCLs

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Electroluminescence Spectra of Available Gain Chip Material