what kind of the type of fiber structure

1 fiber structure:

Optical fiber is generally divided into three bare: center high refractive index glass core (core diameter is generally 50 or 62.5μm), intermediate for low refractive index silica glass cladding (diameter typically 125μm), with the outermost resin coating to enhance layer.

2 NA(Numerical aperture):

The light incident to the fiber end and can not all be transmitted by optical fiber, but in a range of incident angles can. This angle is called the fiber numerical aperture. Larger numerical aperture optical fiber for fiber-docking is favorable. Different manufacturers of fiber numerical aperture different (AT & TCORNING).

3 fiber types:

A. By the light in optical fiber transmission mode can be divided into: single-touch and multi-mode optical fiber.

Multimode fiber: center glass core coarse (50 or 62.5μm), to be available for a variety of modes of light. But its mode dispersion larger, which limits the frequency to transmit digital signals, and with the increase in distance will be more severe. For example: 600MB/KM fiber only when the 2KM 300MB of bandwidth. Therefore, the multi-mode fiber transmission distance is relatively close, usually only a few kilometers. Single-mode fiber: a smaller central glass core (core diameter typically 9 or 10μm), can only transfer a pattern of light. Thus, the mode dispersion is very small, for remote communication, but its chromatic dispersion plays a major role, such single-mode fiber to the light source spectral width and high stability requirements, that spectral width is narrower, stability is better .

B. divided by the best transmission frequency window: conventional single-mode fiber and dispersion shifted single-mode optical fiber. Conventional type: optical fiber manufacturer to optimize the transmission frequency in a single wavelength of light, such as 1300nm. Dispersion-shifted type: production of long fiber optical transmission frequency will be the best home in the two wavelengths of light, such as: 1300nm and 1550nm.

C. divided by the refractive index distribution: mutation type and graded fiber. Mutation type: glass fiber center core to the cladding refractive index is a mutation. Its low cost, high-mode dispersion. For short-distance low-speed communications, such as: industrial control. However, single-mode fiber as mode dispersion is very small, so the single-mode fiber are used mutant. Graded-index fiber: glass fiber center core to the cladding refractive index is gradually smaller, can form high-mode optical communication according to the sine, which can reduce the mode dispersion, improving fiber-optic bandwidth, increased transmission distance, but the cost is higher now than mostly graded multimode fiber optical fiber.

4 Common Fiber Specifications:

Single-mode: 8/125μm, 9/125μm, 10/125μm multimode: 50/125μm, European standard 62.5/125μm, American Standard industrial, medical and low-speed networks: 100/140μm, 200/230μm plastic: 98/1000μm, with in vehicle control