GRIN Fiber Optic Collimators / Couplers, Multimode Fiber

Features

• Couple and Collimate Light Into or Out of a Fiber
• Pigtailed to Graded-Index Multimode Fiber with an Optional FC/PC or FC/APC Connector
• Lens Surface is AR Coated for the Specified Wavelength Range
• Ø1.8 mm Clear Aperture
• 300 mW Maximum Power

Thorlabs offers pigtailed fiber collimators that use Graded-Index (GRIN) lenses. These GRIN collimators feature a Ø1.8 mm clear aperture and are coupled to graded-index multimode (MM) fiber. They are designed to be used in pairs, with a free-space beam between the lenses. They can also be used individually, as a single collimator or coupler. We offer models aligned at 1310 nm or 1550 nm and with a choice of an unterminated fiber end, a 2.0 mm narrow key FC/PC connector, or a 2.0 mm narrow key FC/APC connector. Contact Tech Support for custom connector options.

We also offer single mode pigtailed GRIN collimators and loose GRIN lenses, which can be paired with single mode pigtailed ferrules that have terminated or unterminated fiber ends to create a custom collimator similar to those sold on this page. For Thorlabs' complete selection of fiber collimators, please see the Collimator Guide tab.

Free-Space Coupling
When using GRIN collimators to couple a free-space beam into a fiber, precise alignment is needed for good coupling efficiency. We recommend using a kinematic tip and tilt mount and lens tube adapter, paired with an XYZ adjustable platform (such as our POLARIS-K05T6, SM05PT, sold below, and MT3), or our 6-axis kinematic mount paired with a lens tube adapter (K6XS and SM1PT, sold below).

Collimator Pair with Free-Space Beam
Our GRIN pigtailed collimators are designed to be used in pairs, with a free-space beam between the lenses. This free-space beam can be manipulated with many types of optics prior to entering the second lens. The collimators should be placed with a spacing of 15 ± 5 mm (working distance) between the front lens surfaces for maximum coupling efficiency. When used within the specified working distance and mounted on tip-tilt mounts, typical insertion losses of ≤0.35 dB are possible.

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GRIN Collimator Pair with Free-Space Beam, Mounted with
POLARIS-K05T6 Mirror Mounts and SM05PT Adapters (Sold Below)

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Click on the Pair Performance icon in the tables below to view experimentally measured coupling efficiency data for each collimator pair as a function of the spacing between the collimators. Although the optimal working distance will slightly deviate for any two individual collimators due to small manufacturing variations, these slight deviations do not significantly affect pair or individual performance. This is evidenced by the data given below, which was taken with randomly selected collimators. To achieve the best possible coupling, we recommend mounting both collimators in kinematic adjustable mounts, such as the POLARIS-K05T6 with SM05PT, sold below, for final alignment. All specifications, including beam diameter, beam distance, and pair insertion loss, are guaranteed at a working distance of 15 ± 5 mm for any given collimator pair.

Thorlabs also offers a modular fiber/free-space setup, the FiberBench, which can accommodate pre-aligned FiberPort collimators and allows modular optical components to be placed in the beam path.

Loose GRIN Lenses
Thorlabs also offers single wavelength or broadband loose GRIN lenses for use with either a single wavelength or broadband light source. These GRIN lenses can be paired with our single mode pigtailed ferrules, which are offered with or without connectors. In contrast to the products sold on this page, these options allow the combination of GRIN lens and pigtailed ferrule to be chosen individually, satisfying a wide range of experimental requirements.

Fiber Collimator Selection Guide

Click on the collimator type or photo to view more information about each type of collimator.

Type		Description
Fixed FC, APC, or SMA Fiber Collimators		These fiber collimation packages are pre-aligned to collimate light from an FC/PC-, FC/APC-, or SMA-terminated fiber. Each collimation package is factory aligned to provide diffraction-limited performance for wavelengths ranging from 405 nm to 4.55 µm. Although it is possible to use the collimator at detuned wavelengths, they will only perform optimally at the design wavelength due to chromatic aberration, which causes the effective focal length of the aspheric lens to have a wavelength dependence.
Air-Spaced Doublet, Large Beam Collimators		For large beam diameters (Ø5.3 - Ø8.5 mm), Thorlabs offers FC/APC, FC/PC, and SMA air-spaced doublet collimators. These collimation packages are pre-aligned at the factory to collimate a laser beam propagating from the tip of an FC or SMA-terminated fiber and provide diffraction-limited performance at the design wavelength.
Triplet Collimators		Thorlabs' High Quality Triplet Fiber Collimation packages use air-spaced triplet lenses that offer superior beam quality performance when compared to aspheric lens collimators. The benefits of the low-aberration triplet design include an M2 term closer to 1 (Gaussian), less divergence, and less wavefront error.
Achromatic Collimators for Multimode Fiber		Thorlabs' High-NA Achromatic Collimators pair a meniscus lens with an achromatic doublet for high performance across the visible to near-infrared spectrum with low spherical aberration. Designed for use with high-NA multimode fiber, these collimators are ideal for Optogenetics and Fiber Photometry applications.
Reflective Collimators		Thorlabs' metallic-coated Reflective Collimators are based on a 90° off-axis parabolic mirror. Mirrors, unlike lenses, have a focal length that remains constant over a broad wavelength range. Due to this intrinsic property, a parabolic mirror collimator does not need to be adjusted to accommodate various wavelengths of light, making them ideal for use with polychromatic light. Our fixed reflective collimators are recommended for collimating single and multimode fiber and coupling into multimode fiber. These collimators are available with UV-enhanced aluminum or protected silver reflective coatings and with FC/PC, FC/APC, or SMA connector compatibility.
Compact Reflective Collimators		Thorlabs' Compact Reflective Collimators incorporate a 90° off-axis parabolic mirror with a protected silver coating. Because the focal length is independent of wavelength for an off-axis parabolic mirror, they are ideal for use with polychromatic light. Our fixed reflective collimators are recommended for collimating single and multimode fiber and coupling into multimode fiber. These collimators are directly compatible with our 16 mm cage system. They are available with FC/PC, FC/APC, or SMA connector inputs.
Adjustable Reflective Collimators		Thorlabs' Adjustable Focus Reflective Collimators are based on a 90° off-axis parabolic (OAP) mirror with a protected silver coating. The adjustable fiber-to-OAP distance, combined with the OAP having a constant focal length across wavelengths, makes these collimators ideal for optimizing collimation or coupling of polychromatic light with single mode or multimode fiber. These adjustable collimators have a 15 mm reflected focal length and are available with FC/PC, FC/APC, or SMA connectors.
FiberPorts		These compact, ultra-stable FiberPort micropositioners provide an easy-to-use, stable platform for coupling light into and out of FC/PC, FC/APC, or SMA terminated optical fibers. It can be used with single mode, multimode, or PM fibers and can be mounted onto a post, stage, platform, or laser. The built-in aspheric or achromatic lens is available with five different AR coatings and has five degrees of alignment adjustment (3 translational and 2 pitch). The compact size and long-term alignment stability make the FiberPort an ideal solution for fiber coupling, collimation, or incorporation into OEM systems.
Adjustable Fiber Collimators		These collimators are designed to connect onto the end of an FC/PC, FC/APC, or SMA connector and contain an AR-coated aspheric lens. The distance between the aspheric lens and the tip of the fiber can be adjusted to compensate for focal length changes or to recollimate the beam at the wavelength and distance of interest.
Achromatic Fiber Collimators with Adjustable Focus		Thorlabs' Achromatic Fiber Collimators with Adjustable Focus are designed with an effective focal length (EFL) of 20 mm, 40 mm, or 80 mm, have optical elements broadband AR coated for one of three wavelength ranges, and are available with FC/PC, FC/APC, or SMA905 connectors. A four-element, air-spaced lens design produces superior beam quality (M2 close to 1) and less wavefront error when compared to aspheric lens collimators. These collimators can be used for free-space coupling into a fiber, collimation of output from a fiber, or in pairs for collimator-to-collimator coupling over long distances, which allows the beam to be manipulated prior to entering the second collimator.
Zoom Fiber Collimators		These collimators provide a variable focal length between 6 and 18 mm, while maintaining the collimation of the beam. As a result, the size of the beam can be changed without altering the collimation. This universal device saves time previously spent searching for the best suited fixed fiber collimator and has a very broad range of applications. They are offered with FC/PC, FC/APC, or SMA905 connectors with three different antireflection wavelength ranges to choose from.
Single Mode Pigtailed Collimators		Our single mode pigtailed collimators come with one meter of fiber, consist of an AR-coated aspheric lens pre-aligned with respect to a fiber, and are collimated at one of eight wavelengths: 532 nm, 633 nm, 780 nm, 850 nm, 1030 nm, 1064 nm, 1310 nm, or 1550 nm. Although it is possible to use the collimator at any wavelength within the coating range, the coupling loss will increase as the wavelength is detuned from the design wavelength.
Polarization Maintaining Pigtailed Collimators		Our polarization maintaining pigtailed collimators come with one meter of fiber, consist of an AR-coated aspheric lens pre-aligned with respect to a fiber, and are collimated at one of five wavelengths: 633 nm, 780 nm, 980 nm, 1064 nm, or 1550 nm. Custom wavelengths and connectors are available as well. A line is engraved along the outside of the housing that is parallel to the fast axis. As such, it can be used as a reference when polarized light is launched accordingly. Although it is possible to use the collimator at any wavelength within the coating range, the coupling loss will increase as the wavelength is detuned from the design wavelength.
GRIN Fiber Collimators		Thorlabs offers gradient index (GRIN) fiber collimators that are aligned at a variety of wavelengths from 630 to 1550 nm and have either FC terminated, APC terminated, or unterminated fibers. Our GRIN collimators feature a Ø1.8 mm clear aperture, are AR-coated to ensure low back reflection into the fiber, and are coupled to standard single mode or graded-index multimode fibers.
GRIN Lenses		These graded-index (GRIN) lenses are AR coated for applications at 630, 830, 1060, 1300, or 1560 nm that require light to propagate through one fiber, then through a free-space optical system, and finally back into another fiber. They are also useful for coupling light from laser diodes into fibers, coupling the output of a fiber into a detector, or collimating laser light. Our GRIN lenses are designed to be used with our Pigtailed Glass Ferrules and GRIN/Ferrule sleeves.