Laser Diode Selection Guidea
Shop by Wavelength
UV (375 nm) Visible (404 nm - 690 nm) NIR (705 nm - 2000 nm) MIR (4.05 µm - 11.00 µm)
Shop by Package / Type

• Our complete selection of laser diodes is available on the LD Selection Guide tab above.

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.

OEM & Custom Laser Diodes

Thorlabs manufactures custom and high volume OEM laser diodes and other optical semiconductor devices with output wavelengths from 705 nm to 2 µm. To inquire about custom or OEM devices, please contact us. A semiconductor specialist will contact you within 24 hours or the next business day.

Features

• Laser Diode Types Include:
  • Fabry-Perot (FP)
  • Distributed Feedback (DFB)
  • Volume Holographic Grating (VHG) Stabilized
  • Fiber Bragg Grating (FBG) Stabilized
  • Distributed Bragg Reflector (DBR)
  • Vertical Cavity Surface Emitting Laser (VCSEL)
  • Ultra-Low-Noise (ULN) Hybrid
• Output Powers up to 2 W
• Center Wavelengths Available from 705 nm to 2000 nm
• Various Packages Available: TO Can, TO Pigtails, Butterfly, Extended Butterfly, C-Mount, and Chip on Submount
• Easily Choose a Compatible Mount Using Our LD Pin Codes
• Compatible with Thorlabs' Laser Diode and TEC Controllers
• OEM Solutions Available

This web page contains Thorlabs' laser diodes with center wavelengths from 705 nm to 2000 nm. Diodes are arranged by wavelength and then power. The tables below list basic specifications to help you narrow down your search quickly. Lasers that are highlighted in light green in these tables below are single-frequency laser diodes. The blue button in the Info column within the tables opens a pop-up window that contains more detailed specifications for each item, as well as mechanical drawings.

Notes on Center Wavelength
While the center wavelength is listed for each laser diode, this is only a typical number. The center wavelength of a particular unit varies from production run to production run, so the diode you receive may not operate at the typical center wavelength. Diodes can be temperature tuned, which will alter the lasing wavelength. A number of items below are listed as Wavelength Tested, which means that the dominant wavelength of each unit has been measured and recorded. For many of these items, after clicking "Choose Item" below, a list will appear that contains the dominant wavelength, output power, and operating current of each in-stock unit. Clicking on the red Docs Icon next to the serial number provides access to a PDF with serial-number-specific L-I-V and spectral characteristics. For products listed as Wavelength Tested that do not have the "Choose Item" option, please contact Tech Support with inquires about specific wavelengths.

Packages and Mounts
We offer laser diodes in various packages including standard Ø5.6 mm and Ø9 mm TO packages, non-standard TO-46 packages, as well as fiber-pigtailed TO-packaged diodes, butterfly-packaged diodes, extended butterfly-packaged diodes, chip on submounts, and C-mounts. We have categorized the pin configuration of TO-packaged diodes into standard A, B, C, D, E, F, G, and H pin codes (see image below). This pin code allows the user to easily determine compatible mounts. TO-packed diodes are the most widely supported diodes by our product line, followed by butterfly-packaged lasers. Chip on submount and C-mount lasers are better suited for OEM applications. Our ultra-low-noise (ULN) lasers are housed in extended butterfly packages, which are incompatible with standard butterfly mounts and require custom mounting.

Some of our diodes are offered in header packages that can be converted to a sealed TO can package by request, as indicated in the tables below. Please contact Tech Support for details.

Spatial Mode and Linewidth
We offer laser diodes with different output characteristics (power, wavelength, beam size, shape, etc.). Most lasers offered here are single spatial mode (single mode, or SM) and a few are designed for higher-power, multi-spatial-mode (multimode, or MM) operation. Our wavelength-stabilized VHG laser diodes, sold below, have excellent single mode performance. Some single mode laser diodes can be operated with limited single-longitudinal-mode characteristics (see tables below for additional information). For better side mode suppression ratio (SMSR) performance, consider devices such as DFB lasers, VHG-stabilized lasers, DBR lasers, or external cavity lasers. Thorlabs single-frequency lasers are highlighted in green in the tables below; in particular, our VHG-stabilized, DFB, DBR, and external cavity lasers have narrow linewidths (≤20 MHz for the VHG-stabilized and DFB lasers and <100 kHz for the DBR and ECL lasers). We manufacture ULN laser diodes which allow independent temperature control of the diode and a fiber Bragg grating achieve a typical relative intensity noise -165 dBc/Hz and instantaneous Lorentzian linewidths of less than 100 Hz. Please see the SFL Guide tab above and our Laser Diode Tutorial for more information on these topics and laser diodes in general.

Laser diodes are sensitive to electrostatic shock. Please take the proper precautions when handling the device (see our electrostatic shock accessories). Laser diodes are also sensitive to optical feedback, which can cause significant fluctuations in the output power of the laser diode depending on the application. See our optical isolators for potential solutions to this problem.

For all of the pigtailed laser diodes, the laser should be off when connecting or disconnecting the device from other fibers, particularly for lasers with power levels above 10 mW. We recommend cleaning the fiber connector before each use if there is any chance that dust or other contaminants may have deposited on the surface. The laser intensity at the center of the fiber tip can be very high and may burn the tip of the fiber if contaminants are present. While the connectors on the pigtailed laser diodes are cleaned and capped before shipping, we cannot guarantee that they will remain free of contamination after they are removed from the package.

Members of our Tech Support staff are available to help you select a laser diode and to discuss possible operation issues.

Pin Codes

For warranty information, please refer to the LD Operation tab.

Laser Diode and Laser Diode Pigtail Warranty

When operated within their specifications, laser diodes have extremely long lifetimes. Most failures occur from mishandling or operating the lasers beyond their maximum ratings. Laser Diodes are among the most static-sensitive devices currently made. Proper ESD Protection should be worn whenever handling a laser diode. Due to their extreme electrostatic sensitivity, laser diodes cannot be returned after their sealed package has been open. Laser diodes in their original sealed package can be returned for a full refund or credit.

Handling and Storage Precautions

Due to their extreme susceptibility to damage from electrostatic discharge (ESD), care should be taken whenever handling and operating laser diodes:

• Wrist Straps: Use grounded anti-static wrist straps whenever handling diodes.
• Anti-Static Mats: Always work on grounded anti-static mats.
• Laser Diode Storage: When not in use, short the leads of the laser together to protect against ESD damage.

Operating and Safety Precautions

Use an Appropriate Driver:
Laser diodes require precise control of operating current and voltage to avoid overdriving the laser diode. In addition, the laser driver should provide protection against power supply transients. Select a laser driver appropriate for your application. Do not use a voltage supply with a current limiting resistor since it does not provide sufficient regulation to protect the laser.

Power Meters:
When setting up and calibrating a laser diode with its driver, use a NIST-traceable power meter to precisely measure the laser output. It is usually safest to measure the laser output directly before placing the laser in an optical system. If this is not possible, be sure to take all optical losses (transmissive, aperture stopping, etc.) into consideration when determining the total output of the laser.

Reflections:
Flat surfaces in the optical system in front of a laser diode can cause some of the laser energy to reflect back onto the laser’s monitor photodiode giving an erroneously high photodiode current. If optical components are moved within the system and energy is no longer reflected onto the monitor photodiode, a constant power feedback loop will sense the drop in photodiode current and try to compensate by increasing the laser drive current and possibly overdriving the laser. Back reflections can also cause other malfunctions or damage to laser diodes. To avoid this, be sure that all surfaces are angled 5-10°, and when necessary, use optical isolators to attenuate direct feedback into the laser.

Heat Sinks:
Laser diode lifetime is inversely proportional to operating temperature. Always mount the laser in a suitable heat sink to remove excess heat from the laser package.

Voltage and Current Overdrive:
Be careful not to exceed the maximum voltage and drive current listed on the specification sheet with each laser diode, even momentarily. Also, reverse voltages as little as 3 V can damage a laser diode.

ESD Sensitive Device:
Currently operating lasers are susceptible to ESD damage. This is particularly aggravated by using long interface cables between the laser diode and its driver due to the inductance that the cable presents. Avoid exposing the laser or its mounting apparatus to ESDs at all times.

ON/OFF and Power Supply Coupled Transients:
Due to their fast response times, laser diodes can be easily damaged by transients less than 1 µs. High current devices such as soldering irons, vacuum pumps, and fluorescent lamps can cause large momentary transients. Thus, always use surge-protected outlets.

If you have any questions regarding laser diodes, please call your local Thorlabs Technical Support office for assistance.

ECL, DFB, VHG-Stabilized, DBR, and Hybrid Single-Frequency Lasers

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Figure 1: ECL Lasers have a Grating Outside of the Gain Chip

A wide variety of applications require tunable single-frequency operation of a laser system. In the world of diode lasers, there are currently four main configurations to obtain a single-frequency output: external cavity laser (ECL), distributed feedback (DFB), volume holographic grating (VHG), and distributed Bragg reflector (DBR). All four are capable of single-frequency output through the utilization of grating feedback. In addition, an ECL can be combined with a fiber Bragg grating (FBG) to create a hybrid design. However, each type of laser uses a different grating feedback configuration, which influences performance characteristics such as output power, tuning range, and side mode suppression ratio (SMSR). We discuss below some of the main differences between single-frequency diode lasers.

External Cavity Laser
The External Cavity Laser (ECL) is a versatile configuration that is compatible with most standard free space diode lasers. This means that the ECL can be used at a variety of wavelengths, dependent upon the internal laser diode gain element. A lens collimates the output of the diode, which is then incident upon a grating (see Figure 1). The grating provides optical feedback and is used to select the stabilized output wavelength. With proper optical design, the external cavity allows only a single longitudinal mode to lase, providing single-frequency laser output with high side mode suppression ratio (SMSR > 45 dB).

One of the main advantages of the ECL is that the relatively long cavity provides extremely narrow linewidths (<1 MHz). Additionally, since it can incorporate a variety of laser diodes, it remains one of the few configurations that can provide narrow linewidth emission at blue or red wavelengths. The ECL can have a large tuning range (>100 nm) but is often prone to mode hops, which are very dependent on the ECL's mechanical design as well as the quality of the antireflection (AR) coating on the laser diode.

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Figure 2: DFB Lasers Have a Bragg Reflector Along the Length of the Active Gain Medium

Distributed Feedback Laser
The Distributed Feedback (DFB) Laser (available in NIR and MIR) incorporates the grating within the laser diode structure itself (see Figure 2). This corrugated periodic structure coupled closely to the active region acts as a Bragg reflector, selecting a single longitudinal mode as the lasing mode. If the active region has enough gain at frequencies near the Bragg frequency, an end reflector is unnecessary, relying instead upon the Bragg reflector for all optical feedback and mode selection. Due to this “built-in” selection, a DFB can achieve single-frequency operation over broad temperature and current ranges. To aid in mode selection and improve manufacturing yield, DFB lasers often utilize a phase shift section within the diode structure as well.

The lasing wavelength for a DFB is approximately equal to the Bragg wavelength:

where λ is the wavelength, n_eff is the effective refractive index, and Λ is the grating period. By changing the effective index, the lasing wavelength can be tuned. This is accomplished through temperature and current tuning of the DFB.

The DFB has a relatively narrow tuning range: about 2 nm at 850 nm, about 4 nm at 1550 nm, or at least 1 cm^-1 in the mid-IR (4.00 - 11.00 µm). However, over this tuning range, the DFB can achieve single-frequency operation, which means that this is a continuous tuning range without mode hops. Because of this feature, DFBs have become a popular and majority choice for real-world applications such as telecom and sensors. Since the cavity length of a DFB is rather short, the linewidths are typically in the 1 MHz to 10 MHz range. Additionally, the close coupling between the grating structure and the active region results in lower maximum output power compared to ECL and DBR lasers.

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Figure 3: VHG Lasers have a Volume Holographic Grating Outside of the Active Gain Medium

Volume-Holographic-Grating-Stabilized Laser
A Volume-Holographic-Grating-(VHG)-Stabilized Laser also uses a Bragg reflector, but in this case a transmission grating is placed in front of the laser diode output (see Figure 3). Since the grating is not part of the laser diode structure, it can be thermally decoupled from the laser diode, improving the wavelength stability of the device. The grating typically consists of a piece of photorefractive material (typically glass) which has a periodic variation in the index of refraction. Only the wavelength of light that satisfies the Bragg condition for the grating is reflected back into the laser cavity, which results in a laser with extremely wavelength-stable emission. A VHG-Stabilized laser can produce output with a similar linewidth to a DFB laser at higher powers that is wavelength-locked over a wide range of currents and temperatures.

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Figure 4: DBR Lasers have a Bragg Reflector Outside of the Active Gain Medium

Distributed Bragg Reflector Laser
Similar to DFBs, Distributed Bragg Reflector (DBR) Lasers incorporate an internal grating structure. However, whereas DFB lasers incorporate the grating structure continuously along the active region (gain region), DBR lasers place the grating structure(s) outside this region (see Figure 4). In general a DBR can incorporate various regions not typically found in a DFB that yield greater control and tuning range. For instance, a multiple-electrode DBR laser can include a phase-controlled region that allows the user to independently tune the phase apart from the grating period and laser diode current. When utilized together, the DBR can provide single-frequency operation over a broad tuning range. For example, high end sample-grating DBR lasers can have a tuning range as large as 30 - 40 nm. Unlike the DFB, the output is not mode hop free; hence, careful control of all inputs and temperature must be maintained.

In contrast to the complicated control structure for the multiple-electrode DBR, a simplified version of the DBR is engineered with just one electrode. This single-electrode DBR eliminates the complications of grating and phase control at the cost of tuning range. For this architecture type, the tuning range is similar to a DFB laser but will mode hop as a function of the applied current and temperature. Despite the disadvantage of mode hops, the single-electrode DBR does provide some advantages over its DFB cousin, namely higher output power because the grating is not continuous along the length of the device. Both DBR and DFB lasers have similar laser linewidths. Currently, Thorlabs offers only single-electrode DBR lasers.

Ultra-Low-Noise Hybrid Laser
Thorlabs Ultra-Low-Noise (ULN) Hybrid Lasers each consist of a single angled facet (SAF) gain chip coupled to an exceptionally long fiber Bragg grating (FBG). They are designed to create a laser cavity, similar to an ECL, through the length of fiber. This cavity provides the ULN hybrid laser with a very narrow line width on the order of 100 Hz and low relative intensity noise of -165 dBc/Hz (typical). The FBG reflects a portion of the light emitted from the gain medium while remaining thermally isolated from it. The grating period can be changed by introducing thermal stress to the fiber, allowing users to temperature tune the laser output while being able to independently stabilize the gain medium's temperature. Because the laser's configuration provides excellent low-noise performance, it is likely the laser will not be the limiting factor at low-noise levels. It is critical to monitor the laser's environment to limit external noise contributions like acoustic and seismic vibrations, as well as driving the laser with a low-noise current source.

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Figure 5: Thorlabs Hybrid Lasers have a Fiber Bragg Grating Coupled to the Active Gain Medium

Conclusion
ECL, DFB, VHG, DBR, and hybrid laser diodes provide single-frequency operation over their designed tuning range. The ECL can be designed for a larger selection of wavelengths than either the DFB or DBR. While prone to mode hops, it provides narrow linewidths (<1 MHz). In appropriately designed instruments, ECLs can also provide extremely broad tuning ranges (>100 nm).

The DFB laser is the most stable single-frequency, tunable laser configuration. It can provide mode-hop-free performance over its entire tuning range (<5 nm), making it one of the most popular forms of single-frequency laser for much of industry. It has the lowest output power due to inherent properties of the continuous grating feedback structure.

The VHG laser provides stable wavelength performance over a range of temperatures and currents and can provide higher powers than are typical in DFB lasers. This stability makes it excellent for use in OEM applications.

The single-electrode DBR laser provides similar linewidth and tuning range as the DFB (<5 nm). However, the single-electrode DBR will have periodic mode hops in its tuning curve.

Hybrid lasers can be used to achieve extremely low-noise signals. In order to take advantage of this characteristic, the laser must be isolated from unwanted noise sources, such as acoustic and seismic vibrations and drive current noise.