Basic knowledge of fiber optics

1) Type of fiber

According to the transmission mode of optical fiber, it can be divided into multimode fiber (MMF) and single-mode fiber. The center glass core of multimode fiber is thicker (50 or 62.5μm), which can transmit various modes of light. But its modulus colors bulk, which restricts the transmission of digital signal frequency, therefore, multimode optical fiber transmission distance is relatively close, generally only a few kilometers. Single Mode optical fiber center glass core is very thin (generally 9 or 10μm), can only pass a pattern of light. Therefore, the die colors dispersion is very small, suitable for remote communication. In general, the skin is orange for multimode, * * * for Singlemode.

2)   Fiber Fiber worker wave long

Light is an electromagnetic wave. Visible light partial wavelength range is: 390nm-760nm (nano), greater than 760nm part is infrared light, less than 390nm part is ultraviolet light. The working wavelength of optical fiber is short wavelength 0.85μm, long wavelength 1.31μm and 1.55μm. Optical fiber loss is generally reduced with the wavelength length, 0.85μm loss of 2.5db/km,1.31μm loss for the loss of 0.35db/km,1.55μm for the 0.20db/km, which is the lowest loss of optical fiber, the loss of more than the wavelength 1.65μm tend to increase.

3) optical fiber transmission distance

100BASE-FX Single mode fiber transmission 10-20 km

Multi-mode fiber transmission for 100BASE-FX multimode modules 2 km

1000BASE-LX 5 km with single mode fiber

1000BASE-LX using multimode fiber (50um) to transmit 550m

1000BASE-LX using multimode fiber (62.5um) to transmit 550m

1000BASE-SX using multimode fiber (50um) to transmit 550m

1000BASE-SX using multimode fiber (62.5um) to transmit 275m

1000base-f: Using a pair of multimode or single-mode fiber, when using multimode fiber, the distance between the computer to the hub can be up to 300-550m (500m), the use of single-mode fiber can be up to 3km.

4) Fiber Coupler

The fiber coupler (coupler), also known as the Splitter (Splitter), is simply the component that divides the optical signal from a single fiber into a maximum of one fiber.

Classification:

SC fiber Coupler: Applied to the SC fiber interface, it looks very similar to the RJ-45 interface, but the SC interface appears more flat, the obvious difference is the inside of the contact, if it is 8 thin copper contacts, it is the RJ-45 interface, if a copper column is SC fiber interface.

LC Fiber COUPLER: Applied to the LC fiber interface, the connector that connects the SFP module, it is made of the easy-to-use modular jack (RJ) latch mechanism. (routers commonly used)

FC Fiber Coupler: Applied to FC Fiber interface, external strengthening method is the use of metal sleeve, fastening method for turnbuckle. Generally used on ODF side (the most used on the wiring frame)

St Fiber Coupler: Applied to St Fiber interface, commonly used in fiber optic wiring frame, shell is round, fastening method is turnbuckle. (For 10BASE-F connections, connectors are usually of type St.) Commonly used in fiber optic wiring racks)

5) Fiber optic pigtail and fiber optic jumper

Simply said pigtail refers to the end of the interface, the other end is a fiber optic device, fiber optic jumper is the interface at both ends, the middle of the optical fiber device. A fiber jumper is cut from the middle to become two pigtail.

6) interface of optical fiber

FC interface type: FC connector is also called Round with threaded connector (the most used on the wiring frame), is a metal joint, generally used in the ODF side, the number of metal joints can be inserted more than plastic.

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SC interface Type: SC connector also known as the card-type square connector (router switch with the most), is a standard square-type connector, the use of engineering plastics, with high temperature, not easy oxidation advantages. The transmission device side optical interface is generally used SC connector.

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LC Connector Type: LC connectors are similar in shape to SC connectors and smaller than SC connectors.

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St Connector: St Connector is also called snap-in type round joint, for 10BASE-F connection, the connector is usually St type.

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Basic knowledge of fiber optics