Mems

MEMS UPGRADING OPTICAL

There are two ways of increasing the transmission capacity of a fiber. The first method is to increase the bit rate, which demands matching high-speed electronics and costly equipment. It also carries a fundamental limit set by the physical parameters of the equipment. In the second method, many lower-speed streams are multiplexed into a high speed stream. By means of electronic time-division multiplexing (TDM), a maximum bit rate of 40Gbps can be achieved. To go beyond this limit, the only means available is optical systems. Wavelength-Division Multiplexing (WDM) can be viewed as an optical domain version of frequency-division multiplexing (FDM), in which multiple information signals modulate optical signals at different optical wavelengths or colours. Prisms and diffraction gratings are used to combine and split colour signals. Wavelength demultiplexer is similar to a prism that can separate light into individual colours.

WDM system may use 16 wavelengths, each one of 2.5Gbps rate, providing an aggregate rate of 40Gbps. A WDM with 32 wavelengths can attain a bit rate of 320Gbps

DWDM (Dense Wavelength-Division Multiplexing )

A superior version of WDM is called Dense WDM (DWDM) with 4,8 and 16 wavelengths became available in the mid 1990s. During the year 2000, Nortel Networks introduced 160 wavelengths at 10Gbps and Fujitsu introduced 176 wavelengths at a bit rate of10Gbps

UDWDM (Ultra-Dense Wavelength-Division Multiplexing ) Ultra-Dense WDM (UDWDM) that can accommodate 320 or 640 wavelengths, all multiplexed in a single fiber.

CONCLUSION The above discussed techniques are some of the ways in which bit rate and transmission distance can be increased in optical communication. Therefore MEMS technology helps in matching the super fast speed of to day’s optical fiber channels and promises tremendous dollar savings over costly electrical conversions.