2015年5月22日星期五

A litte About The Fibre Optic Transceiver

The practicality and conveniency offered Fibre Optic Transceivers is far much greater than the normal transmission of information through electrical wires. Fiber optic transceivers are self-contained components that usually combine a fiber optic transmitter and a fiber optic receiver in a single module. The main role of optical module is photoelectric conversion, where the transmitter end takes in and converts electrical signal into light, which is after the the optical fiber transmission in the fiber cable plant. Then, the receiver end again converts the light signal into an electrical signal. They are usually arranged in parallel so that they can operate without relying on each other. Both the fiber optic transmitter and fiber optic transceiver possess their own circuitry and can handle the transmissions in both directions. Usually, transceivers are inserted in various devices such as network interface cards and routers which basically provide more than one transceiver module slot.

Fiber optic transmitters consist of four types of sources that convert electrical signals into optical signals. They include fabry-perot (FP), LEDs, vertical cavity surface-emitting lasers, and distributed feedback (DFB). As for the fiber optic receivers, they simply use photodiodes or photodetectors (semiconductor detectors) to convert optical signals into electrical signals. For short wavelength links, Silicon photodiodes are used. Indium gallium arsenide detectors are used for long wavelength links as they produce less noise as compared to germanium, which allows for more sensitive receivers. In cases of high speed systems, avalanche photodiodes.

How Fiber Optic Transceivers Work

In the fiber optics, the transmitters usually convert an electrical signal into an optical signal. This conversion is usually coupled with a connector and is transmitted through a fiber optic cable. Then, the light coming from the end of the cable is connected to a receiver and a detector simply converts the light back into an electrical signal. In this case, the light source is usually a laser diode or a light emitting diode.

Types of Fiber Optic Transceivers

the OPTICAL TRANSCEIVER is available in different types in the market. All these types differ in several ways: type of connections, data transmission speeds, and packing forms. The most popular types of types of fiber optic transceivers available in the market are SFP, SFP+, XFP, X2, Xenpak, and GBIC. Depending on the fiber type each FIBER OPTIC TRANCEIVER connects to, they are designed for use with the SM (single mode), MM (multimode), and WDM fiber (DWDM, CWDM modules). Single-mode fibers usually transmit infrared laser light at wavelengths ranging from 1,300 to 1,500 nm. Since they have smaller cores, they are ideal for use with laser sources for high speed, long distance links. As for the multimode fibers, they are used with LEDs sources and the transmission speeds and distance limits are usually 100Mbits/s for 2km, 1Gbits/s for 220-550m, 10Gbit/s for up to 300m. LED sources are ideal for lower speeds and shorter distance links.

Anyone who intends to purchase fiber optic transceivers should not only specify the cable and the connector type, but also the basic requirements for the wavelength, data rate, operating voltage, and the bandwidth. This is to avoid choosing the wrong type of an OPTICAL TRANSCEIVER.

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