HP 6125XLG HP Comware-Based Switches Transceiver Modules User Guide - Page 7

The commonly used fiber modules include optical transmitters, optical receivers, transceivers, and transponders. The HP Comware-Based Switches support transceiver modules. The HP Comware-Based Switches support fiber transceiver module models of different specifications. You can choose fiber transceiver modules as needed for data transmission over optical fibers. The transmitter of a fiber transceiver module converts electrical signals to optical signals, and the receiver converts optical signals to electrical signals. A fiber transceiver module provides the following functions: optical power control, modulation transmission, signal probe, IV conversion, and limiting amplifier and decision regeneration. In addition, transceivers provide some other functions, such as counterfeit-prevention query and TX-disable. Common transceivers include SIP9, SFF, SFP, GBIC, XFP, SFP+, QSFP+, and CFP. Data rate Data rate is the number of bits transmitted per second. The unit of measure for data rate is Megabits per second (Mbps) or Gigabits per second (Gbps). The fiber transceiver modules available for the HP Comware-Based Switches mainly provide the following levels of data rates: 100 Mbps, 1000 Mbps, 10 Gbps, 40 Gbps, and 100 Gbps. Transmission distance For fiber transceiver modules, the following types of transmission distances are available: short haul, middle reach, and long haul. A distance of 2 km (1.24 miles) is considered as short haul, 10 km (6.21 miles) to 20 km (12.43 miles) as middle reach, and 30 km (18.64 miles) and over as long haul. Transmission distances provided by fiber transceiver modules are mainly limited by certain loss and dispersion suffered during the transmission of fiber signals over fibers.  Loss is the optical energy loss due to the absorption, dispersion and leakage over the media when light travels through optical fibers. This loss increases in direct ratio to transmission distance.  Dispersion happens mainly because electromagnetic waves of different wavelengths travel at different rates over the same medium, causing different wave components of optical signals to reach the receiving end early or late as the transmission distance increases, which in turn causes impulse broadening, making the signal values indistinguishable. To meet different transmission distance requirements, choose suitable fiber transceiver modules according to actual networking conditions. Central wavelength Central wavelength represents the wave band used for optical signal transmission. The following central wavelengths are available for common fiber transceiver modules: 850 nm, 1310 nm, and 1550 nm, respectively representing three wavebands.  The 850 nm wave band is used for short-reach transmission.  The 1310 nm and 1550 nm wave bands are used for middle-reach and long-haul transmissions. 3