Полимерлік оптикалық талшықтар

Optical fiber that is made out of polymer

Plastic optical fiber (POF) or polymer optical fiber is an optical fiber that is made out of polymer. Similar to glass optical fiber, POF transmits light (for illumination or data) through the core of the fiber. Its chief advantage over the glass product, other aspect being equal, is its robustness under bending and stretching.

Since 2014 a full family of PHY transceivers have been available in the market enabling the design and manufacturing of home networking equipment delivering Gigabit speeds into the home. One of the most exciting developments in polymer fibers has been the development of microstructured polymer optical fibers (mPOF), a type of photonic crystal fiber.

Traditionally, PMMA (acrylic) comprises the core (96% of the cross section in a fiber 1mm in diameter), and fluorinated polymers are the cladding material. Since the late 1990s much higher performance graded index (GI POF) fiber based on amorphous fluoropolymer (poly(perfluoro butenylvinyl ether), CYTOP) has begun to appear in the marketplace. Whereas glass fibers are only manufactured by drawing, polymer optical fibers can also be manufactured by drawing.

PMMA is used as the core, with a refractive index of 1.49. Generally, fiber cladding is made of fluorinated polymers (refractive index <1.40). High refractive index difference is maintained between core and cladding. High numerical aperture. Have high mechanical flexibility and low cost. Industry standard (IEC 60793 2 40 A4a.2) step index fiber has a core diameter of 1mm. Bandwidth is ~5 MHz km @ 650 nm. It is possible to write fiber Bragg gratings in single and multimode POF. There are advantages in doing this over using silica fiber since the POF can be stretched further without breaking, some applications are described in the PHOSFOS project page.

Optical fiber used in telecommunications is governed by European Standards EN 60793 2 40 2011. Several standardization bodies at country, European, and worldwide levels are currently developing Gigabit communication standards for POF aimed towards home networking applications. It is expected the release at the beginning of 2012. An IEEE study group and later task force has been meeting since then until the publication on 2017 of the IEEE802.3bv Amendment. IEEE 802.3bv defines a 1 Gigabit/s full duplex transmission over SI POF using red LED. It is called 1000BASE RH. This Gigabit POF IEEE standard is based on multilevel PAM modulation a frame structure, Tomlinson Harashima Precoding and Multilevel coset coding modulation. The combination of all these techniques has proven to be an efficient way of achieving low cost implementations at the same time that the transmission theoretical maximum capacity of the POF is approached. Other alternatives are schemes like DMT, PAM 2 NRZ, DFE equalization or PAM 4. VDE standard was published in 2013. After the publication the IEEE asked VDE to withdraw the specification and bring all the effort to IEEE. VDE withdrew the specification and a CFI was presented to IEEE in March 2014.