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The BFTU secures the connector using a 2-56 setscrew and the fiber using a spring-loaded, button-actuated clamp.

Features

• Temporary Fiber Termination
• Mechanically Holds the Fiber and Connector in Place without Epoxy
• Reusable Design
• Compatible with the Thorlabs Fiber Connectors Listed Below

For applications where a temporary fiber termination is desired, our BFTU Bare Fiber Terminator is the solution. The bare fiber terminator is designed to hold fibers in standard connectors (sold separately). The back of the connector is held in place using a 2-56 setscrew, while the fiber is secured with a spring-loaded, button-actuated clamp (see photo to the right).

The BFTU accepts ferrules up to Ø0.158" (Ø4 mm) and fibers up to Ø0.03" (Ø0.7 mm). It is reusable and can be easily cleaned out if the fiber breaks inside the connector by using WC100 clean out wires (sold separately below).

Mechanical Fiber-to-Fiber Splice Kits

Thorlabs offers reusable, mechanical fiber-to-fiber splices allowing easy splicing of two single mode (TS125) or multimode (TS128) fibers. The reusable splices come preloaded with index matching gel guaranteeing an average splicing loss of 0.2 dB. Additional index matching gel (G608N3) is available for reusing of the splice. Both reusable splices feature a glass viewport enabling easy alignment of the fibers. The splices are also equipped with collet clamps to protect the splice against tension applied to the fibers.

For additional fiber termination products, please see our Connector Mating Sleeves, Single mode Connectors and our Multimode Connectors.

Fiber Splice Assembly

1. Required materials

Before beginning a fiber splice, be sure to have the required materials available.  This includes the Reusable Fiber-to-fiber Splice, part number TS125 for single mode fiber or TS128 for multimode fiber.  Additional materials include a fiber stripper, fiber scribe (S90R), 99% pure hospital grade isopropanol, and Kimwipes (KW32).  Fibers compatible with this splice unit are either 125 µm single mode fiber or 128 µm multimode fiber with coating diameter ranging from 250 – 900 µm.  Therefore, the model numbers of fiber stripper include T06S13, T08S13, or T08S40.  Please consult the Thorlabs catalog or web site for additional information about these tools.

7. Special Instructions for Using 900 µm Coating Fibers

Skip to step 8 if you are not using 900 µm fiber.

8. Final Assembly

You are now ready to begin inserting the ends of the two fibers to be spliced into the Reusable Fiber-to-Fiber Splice.  An effective technique is first to couple a source of visible light into one of the fibers.  This will assist by providing visual feedback when the two fiber ends have achieved optimal coupling.  Also, be sure not to adjust the gray collet clamps until instructed to do so.

Index Matching Gel

Thorlabs G608N3 is a crystal clear, gel-like, optical coupling compound intended to reduce signal attenuation in wave guide assemblies at connections.  The presence of air at the junction of two optical fibers causes significant signal refraction due to the large differential optical impedance that exists between air and the signal-carrying wave guides.  The optical coupling compound G608N3 has been formulated with the requisite optical properties of clarity, purity, and refractive index to minimize signal losses while allowing pliable mechanical connections between rigid parts. Unlike a rigid optical epoxy, this pliable gel is viscoelastic and can take up the differential thermal expansion of precision optical parts without inducing excessive stresses or delamination.

In many devices, these materials serve an additional function: they help seal out ambient dust or fluids from sensitive optical components. This gel is formulated to be ultraclean, non-yellowing, and unaffected by x-ray, ultraviolet or sunlight exposure. It has extremely low outgassing and volatility characteristics and is free from light-absorbing microscopic particulates. This optical product is a chemically stable, non-toxic, synthetic material with wide temperature serviceability and is suitable for designs with high reliability and long service life. Each syringe comes with 3 cc of index matching gel that can be used to refill the TS125 and TS128 Fiber-to-Fiber Splice Kits above.

This index matching gel can also be used to eliminate possible air gaps between fibers when mating connectors using a mating sleeve.

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Splice protector sleeve in fiber splicer

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Effects of heating on splice protector sleeves.

Features

• Fits Fiber Outer Diameter up to 900 µm
• Available in Either 40 mm or 60 mm Lengths
• Ø3.2 mm After Shrinking
• Sold in Packs of 25

Thorlabs’ Splice Protector Sleeves are designed to protect splices in fibers with an outer diameter up to 900 µm. These fusion splice protector sleeves are an economic solution that offers reliable and solid protection for splice joints. An outer shrink tube holds the tube through which the fiber is threaded as well as the strength member, a solid steed rod that provides rigid support for the splice joint. This design not only provides a replacement for the original fiber cable jacket, but also provides excellent rigidity around the splice joint, preventing the spliced area from bending or flexing.

To use, thread the fiber through the inner fiber tube of the sleeve. Position the sleeve so that the splice joint is in the middle. The sleeve must then be heated causing the outer shrink tube to contract to Ø3.2 mm. Proper heating is required to ensure an accurate fit and function of the splice protector sleeve. The image to the left illustrates the effects of proper and improper heating on these sleeves. The top image shows normal heating; here the shrink tube is uniform across the splice, providing permanent and rigid protection. The middle image shows excessive heating; here the shrink tube shows evidence of blemishes and melts in the tubing. The bottom image shows insufficient heating; here the shrink tube is not uniform across the splice, resulting in loose or poor protection for the splice joint. A fiber splicer can be used to ensure proper heating of the sleeve (refer to the operation manual of your splicer for correct heating settings). The image to the right shows a properly heated splice protector sleeve in a fiber splicer (see Splice Sleeve Guide tab for more information).

The clear outer tube of the splice protector sleeves allows the color of the optical fiber itself to be seen. These sleeves come in two standard sizes of 40 mm and 60 mm. They cannot be cut due to the steel rod that provides support for the splice joint. Custom lengths are available; please contact Tech Support for more information.

Thorlabs offers splice-ready connectors, single mode, fiber to fiber splice kits, fiber cleavers, and stripping & crimping tools for splicing fibers.