What type of optic fiber structure

1 fiber structure:
Fiber optic fiber is generally divided into three layers: the central core of high refractive index glass (core diameter is usually 50 or 62.5μm), intermediate for low refractive index silica glass cladding (diameter typically 125μm), with the outer resin coating to enhance layer.

(2) numerical aperture:
Incident light and the fiber end face can not all be transmitted by optical fiber, but in a way, it can be within the scope of the incident light and this angle is called the fiber numerical aperture of fiber numerical aperture for optical fiber butt bigger is good 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: thick center glass core education (50 or 62.5μm), multiple modes of light can pass, but its mode dispersion large, which limits the frequency of transmission of digital signals, and increase with distance will be more severe For example: 600MB/KM fiber in 2KM only when the bandwidth of 300MB, so multi-mode fiber transmission distance is relatively close, generally only a few kilometers single-mode fiber: center glass core to teach small (core diameter is generally 9 or 10μm), only one mode of light transmission, so the mode dispersion is small, suitable for remote communication, but the chromatic dispersion plays a major role, so that single-mode fiber for the light source spectral width and stability are more high demand that the spectral width is narrower, better stability.

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

C. divided by the refractive index distribution: mutation type and graded fiber.

Mutant: fiber center core to the cladding refractive index of glass is the mutation of its low cost, high-mode dispersion is suitable for short low-speed communications, such as: industrial, but the single-mode fiber as mode dispersion is small, so a single mode fiber are used mutant.

Graded-index optical fiber: Glass fiber center core to the cladding refractive index is gradually smaller, can form high modulus by the sine of light transmission, which can reduce mode dispersion, increase fiber bandwidth and increase the transmission distance, but the cost is higher now than mode optical fiber mostly graded 4. common fiber specifications:

Single-mode: 8/125μm, 9/125μm, 10/125μm
Multi-mode: 50/125μm European standards, 62.5/125μm American Standard
Industrial, medical and low-speed networks: 100/140μm, 200/230μm
Plastic: 98/1000μm for automotive control.