Fiber Optic Wiki

Optical fiber connector Testing

July 16, 2011

Glass fiber optic connector performance is affected both by the connector and glass. In an otherwise perfect-looking assembled connector, typical adverse factors include: connector (ferrule) concentricity tolerance, fiber diameter tolerance, fiber core concentricity tolerance (within the fiber), core optical parameter tolerance, stress in the polished fiber causing excess return loss, fiber "pistoning" eg lengthwise movement (usually poor glue), incorrect shaping of the connector tip as a result of polishing. It can be readily seen that the connector manufacturer has little control over many of these, so in-service performance may well be below the manufacturer's specification for these reasons.

Small form-factor pluggable transceiver

July 16, 2011

The small form-factor pluggable (SFP) or Mini-GBIC is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. It interfaces a network device mother board (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable.

Small form-factor pluggable transceiver Types

July 16, 2011

SFP transceivers are available with a variety of transmitter and receiver types, allowing users to select the appropriate transceiver for each link to provide the required optical reach over the available optical fiber type (e.g. multi-mode fiber or single-mode fiber). Optical SFP modules are commonly available in several different categories:850 nm 550 m multi-mode fiber (SX),1310 nm 10 km single-mode fiber (LX),1490 nm 10 km single-mode fiber (BS-D),1550 nm 40 km (XD), 80 km (ZX), 120 km (EX or EZX)],1490 nm 1310 nm (BX), Single Fiber Bi-Directional Gigabit SFP Transceivers.

Built-in variable fiber-optic attenuators

July 15, 2011

Built-in variable optical attenuators may be either manually or electrically controlled.

Variable fiber-optic test attenuators

July 15, 2011

Variable Fiber Optic Test Attenuators generally use a variable neutral density filter. Despite relatively high cost, this arrangement has the advantages of being stable, wavelength insensitive, mode insensitive, and offering a large dynamic range. Other schemes such as LCD, variable air gap etc. have been tried over the years, but with limited success.

Light scattering,Specular reflection,Diffuse reflection

July 15, 2011

The propagation of light through the core of an optical fiber is based on total internal reflection of the lightwave. Rough and irregular surfaces, even at the molecular level of the glass, can cause light rays to be reflected in many random directions. This type of reflection is referred to as "diffuse reflection", and it is typically characterized by wide variety of reflection angles. Most objects that can be seen with the naked eye are visible due to diffuse reflection. Another term commonly used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation. Light scattering from many common surfaces can be modelled by lambertian reflectance.

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