Webpage Features
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Features

• Gain Chips Mounted for Easy Integration into External Cavity Lasers
• Half-Butterfly Assembly with Thermoelectric Cooler
• AR Coating Eliminates Unwanted Reflections, Increasing Laser Stability, Output Power, and Spectral Quality
• FP Chip Designed for Use in a Free-Space Littman Cavity
• SAF Chips Feature 1.5 m Long, SM or PM Tight Jacket Pigtail with FC/APC Connector

Fabry-Perot Gain Chip
Thorlabs' Fabry-Perot Gain Chip (TFP780A) provides a gain medium for light in the 740 - 800 nm spectral range. Optimized for high gain, high power, broad tunability, and minimal mode hopping, this gain chip is mounted in a half-butterfly package that exposes both ends of the gain medium to free space. A thermoelectric cooler (TEC) and thermistor, incorporated into the half-butterfly package and controlled with the easily accessible supplied leads (see the Graphs tab), enable tuning and optimization of the operating temperature. Both exposed surfaces of the gain medium are AR coated, virtually eliminating unwanted reflections.

The TFP780A is designed for use in a free-space Littman cavity (see the Graphs tab for a schematic). Thorlabs recommends the TLK-P00 Mounting Plate, which provides a complete solution for tuning the output wavelength of the gain chip. The input and output both couple into free space. If fiber coupling is desired for your application, please consider our SAF Gain Chips, listed below.

This device can also be coupled with a semiconductor optical amplifier to increase its output power. Please contact Tech Support for more information.

SAF Gain Chips
Thorlabs' family of Single-Angled-Facet (SAF) Gain Chips provides a gain medium for light in wavelength ranges centered at 1050, 1220, 1320, 1550, or 1900 nm. These gain chips feature AR coatings, an angled waveguide, and a proven SOA structure, which gives designers of external cavity lasers (ECLs) the highest power and widest tuning range available on the market. The gain chip is mounted in a half-butterfly package that collimates the output of the normal facet and couples it into an FC/APC connector. A thermoelectric cooler (TEC) and thermistor, incorporated into the package and controlled with the easily accessible supplied leads (see the Graphs tab), enable tuning and optimization of the operating temperature.

These gain chips are designed for use in a Littrow-configured cavity (see the Graphs tab for a schematic). The 26.5° exit angle is well matched to Thorlabs' TLK-P26 Mounting Plate, providing a complete solution for tuning the output wavelength of the gain chip. The models designed for 1220, 1320, or 1550 nm (SAF1175S, SAF1174S, SAF1550S2, and SAF1550P2) additionally incorporate an optical isolator on the fiber output. The isolator protects the gain chip against unwanted back reflections from an external system, increasing laser stability, output power, and spectral quality.

On certain models, we can optionally provide a PM fiber or an optical isolator for the free-space input. Please contact Tech Support for a quote.

This link opens a document that contains a comprehensive list of performance specifications and performance plots.

All quoted values are typical. Please see the gain chip's Spec Sheet (linked below) for the most detailed information on performance. The Graphs tab describes the typical performance obtained in an external cavity laser configuration.

General Specifications
Item #	Spec Sheet	Reference Cavity	CWLa	Tuning Rangea, b	Peak Powera	Chip Gainc	Gain Ripple	R1	R2	Chip Length
TFP780A		TLK-L780M	770 nm	30 nm	50 mW	-	3 dB	0.01%	90%d	0.75 mm
SAF1171S		TLK-L1050M	1050 nm	60 nm	8 mW	30 dB	2.5 dB (Max)	0.005%	10%e	1 mm
SAF1175S		Littmann Cavity (Offered as OEM)	1220 nm	90 nm	40 mW	17 dB	0.5 dB	0.005%	10%e	1 mm
SAF1174S		TLK-L1300R	1310 nm	100 nm	50 mW	35 dB	0.35 dB	0.005%	10%e	2 mm
SAF1550S2		TLK-L1550R	1550 nm	120 nm	40 mW	17 dB	0.4 dB (Max)	0.005%	10%e	1 mm
SAF1550P2		TLK-L1550R	1550 nm	120 nm	40 mW	17 dB	0.4 dB (Max)	0.005%	10%e	1 mm
SAF1900S		TLK-L1900M	1900 nm	120 nm	7 mW	18 dB	1.5 dB	0.005%	20%e	2 mm

All values are typical, unless otherwise indicated.
^a The values given in the highlighted columns were measured in the specified reference cavity. Different external cavities will produce different performance specifications.
^b 10 dB point.
^c Single-pass optical gain at center of gain curve.
^d Refer to the FP chip reflectivity diagram below.
^e Refer to the SAF chip reflectivity diagram below.

Fabry-Perot Gain Chip Lasing Performance Using Littman Tunable Laser Kit

The Fabry-Perot (FP) laser diode has the two parallel ends of the semiconductor cleaved atomically flat to produce an oscillating cavity. Laser light is typically emitted through one of these highly reflective edges, using the semiconductor as the gain medium. FP lasers typically lase in a single longitudinal mode and exhibit temperature-dependent tunability over a small range. Since the end facets of the chip form the laser cavity, different longitudinal modes also appear in the emission, broadening the linewidth (100 - 1000 GHz). Given below are the typical TFP780A spectra and details on the packaged devices.

Part #	Center Wavelength	Power vs. Current	Power Spectrum
TFP780A	770 nm

SAF Gain Chip Lasing Performance Using Littrow Tunable Laser Kit

The innovative design of an SAF gain chip is ideal for use in external cavity lasers because it virtually eliminates unwanted feedback from the intracavity facet of the gain chip. These devices offer superior performance in a wide variety of external cavity configurations. Given below are typical spectra and details on the packaged devices.

Part #	Center Wavelength	Power vs. Current	Power Spectrum
SAF1171S	1050 nm
SAF1175S	1220 nm
SAF1174S*	1320 nm
SAF1550S2	1550 nm
SAF1550P2	1550 nm
SAF1900S	1900 nm

*Please note that the fluctuations in the power spectrum between 1350 and 1380 nm are associated with water vapor absorption. The power at these wavelengths can be improved by purchasing the TLK-E sealed laser enclosure and purging the enclosure with gas.