Shulou(Shulou.com)06/01 Report--

1) types of optical fiber

According to the transmission mode of light in optical fiber, it can be divided into multimode optical fiber (MMF) and single-mode optical fiber. The central glass core of multimode fiber is thicker (50 or 62.5 μ m) and can transmit light in multiple modes. However, the dispersion between modes is large, which limits the frequency of digital signal transmission. therefore, the transmission distance of multimode optical fiber is relatively close, generally only a few kilometers. The central glass core of single-mode fiber is very thin (the core diameter is usually 9 or 10 μ m) and can only transmit light in one mode. Therefore, the dispersion between modes is very small and is suitable for remote communication. In general, the orange skin is multi-mode and * single-mode.

2) the working wavelength of optical fiber

Light is a kind of electromagnetic wave. The wavelength range of the visible part is 390nm-760nm (nanometer), the part larger than 760nm is infrared light, and the part smaller than 390nm is ultraviolet light. The operating wavelengths of the optical fiber are 0.85 μ m for short wavelength, 1.31 μ m for long wavelength and 1.55 μ m for long wavelength. The loss of optical fiber generally decreases with the increase of wavelength, the loss of 0.85 μ m is 2.5dB/km, the loss of 1.31 μ m is 0.35dB/km, and the loss of 1.55 μ m is 0.20dB/km, which is the lowest loss of optical fiber, and the loss above 1.65 μ m tends to increase.

3) Optical fiber transmission distance

100base-fx single mode module uses single mode optical fiber to transmit 10-20 km.

100base-fx multimode module uses multimode optical fiber to transmit 2km

1000base-lx uses single-mode optical fiber to transmit 5km

Multimode Optical Fiber (50um) Transmission 550m for 1000base-lx

Multimode Optical Fiber (62.5um) Transmission 550m for 1000base-lx

Multimode Optical Fiber (50um) Transmission 550m for 1000base-sx

1000base-sx uses multimode optical fiber (62.5um) to transmit 275m

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

4) Optical fiber couplers

Optical fiber coupler (Coupler), also known as bifurcator (Splitter), is simply a component that divides optical signals from one optical fiber to multiple optical fibers.

Classification:

SC optical fiber coupler: used in SC optical fiber interface, it looks similar to RJ-45 interface, but SC interface appears flatter, the obvious difference is the contact piece inside, if it is 8 thin copper contact piece, it is RJ-45 interface, if it is a copper post, it is SC optical fiber interface.

LC optical fiber coupler: a connector used in LC fiber interface to connect SFP modules. It is made of a modular Jack (RJ) latch mechanism that is easy to operate. (commonly used in routers)

FC optical fiber coupler: used in FC optical fiber interface, external strengthening mode is metal sleeve, fastening mode is screw buckle. It is generally used on the ODF side (most used on the distribution frame)

ST optical fiber coupler: used in ST optical fiber interface, often used in optical fiber distribution frame, the shell is round, fastening mode is screw buckle. (for 10Base-F connections, connectors are usually of ST type. Commonly used in optical fiber distribution frames)

5) Optical fiber tail and optical fiber jumper

To put it simply, tail fiber refers to a device with an interface at one end and an optical fiber at the other, and an optical fiber jumper is a device with an interface at both ends and an optical fiber in the middle. Cut an optical fiber jumper in the middle to form two tails.

6) the interface of optical fiber

FC interface type: FC joint is also called round threaded joint (the most used on the distribution frame), it is a metal joint, which is generally used on the ODF side, and the metal joint can be plugged out more times than plastic.

SC interface type: SC connector is also called clamping square connector (most used on router switch). It is a standard square connector and adopts engineering plastic. It has the advantages of high temperature resistance and not easy oxidation. The optical interface on the side of the transmission equipment usually uses the SC connector.

LC interface type: the LC connector is similar to the SC connector in shape and smaller than the SC connector.

ST connectors: ST connectors are also called clamping round connectors. For 10Base-F connections, connectors are usually of the ST type.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.