The F-SMA 905 connector has been a standard in fiber optics for many years. Originally from the telecom sector, it has long since ceased to be used there. Due to the high-precision sigle-mode fibers with mode field diameters in the μm range used there, other, more precisely centerable connector types were necessary. To reduce the insertion loss highly centric connectors, if possible without air gap, are necessary. Therefore, PC (physical contact) connectors such as SC, FC/PC or ST dominate here. Plugs like the FC-APC even reduces back reflection by tilting the end faces 8 °.

In the laser sector, the SMA is still the ideal solution for many applications in the lower power range. The simple design of the SMA ferrule allows easy adaptation to different fiber diameters, even for single pieces and small batches. For core Diameters >50μm, centricity deviations by a few μm are less relevant. Fibers with core diameters from 50μm to 1000μm can be used. Fiber bundles and arrays are sometimes possible up to 2.5mm bundle diameter.

For low power, even fiber-to-fiber couplings with defined air gaps - without separate optics - are possible with the SMA.

The SMA connector is also frequently used for sensors and spectroscopy. Here are also special designs such as linear Arrays, round bundle arrangements or Y-branched fiber optic - for example, for reflection probes - possible.

Also in the field of POF (polymer optical fibers), the SMA, mostly in the less precise type I version, is often the connector of choice.

Due to increasing demands in laser applications, many improvements have been made on the SMA connector in the past. Typically, copper ferrules for free-standing fiber ends are currently used for medium power up to 500 W (BF-SMA-HP). Here, it is important to process the fibers as centrically as possible and in the coupling-in area without adhesive, so that scattered laser radiation does not lead to absorption and fiber burn-off. The Cu-Ferrules ideally reflect IR scattered light while allowing good heat dissipation. Where in the standard plug mainly the ferrule was getting hot, distributes the heat here to the entire plug to the aluminum sleeve. If required, air or water cooling can also be applied.

For all applications for which the LLK-A is too big and expensive, but the SMA is not powerful enough, the use of the BF-D81 is recommended. Here, the so-called LD80 has been further optimized to best meet the high requirements in terms of laser power and heat dissipation.

At Berlin Fiber, the BF-SMA, the BF-SMA-HP and the BF-D81 are part of a modular system which offers different combinations and optional functions thanks to the different hose connection sleeves. This makes it possible to implement special customer requirements at relatively short time - even as one-off production.

Properties of the BF-SMA

  • Dimensions according to DIN EN 61754-22
  • Ferrule material made of stainless steel or ARCAP AP1D
  • Connecting thread: US 1/4 "-36
  • various sleeves for metal hoses with AD 5mm, 6.5mm and OD 11mm available
  • also combinable with 3mm plastic protective hose (FT030)
  • Use for fiber arrays or bundles up to 2.5mm possible

Properties of the BF-SMA-HP

  • Ferrule made of Copper
  • Fiber end freestanding
  • Fiber glued in the back of the plug or mounted without glue
  • improved heat Dissipation
  • high reflectivity for IR scattered Radiation


  • Mode strip configuration to reduce cladding modes
  • Air or water cooling
  • Breakage protection with interlock Connection
  • Thermal fuse

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