Dispersion Compensated Broad Band Optical Communication Link
Introduction
The phenomenal growth of Internet traffic has led to an explosive growth in demand for Bandwidth (BW) and this in turn has led to the need for higher bit transmission rates, longer distances and scalability. At present the key for increasing transmission carrying capacity of an optical fibre lies in employing Dense Wavelength Division Multiplexed) DWDM transmission by transmitting signal using multiple wave lengths offered by optical fiber amplifiers like Erbium Doped Fibre Amplifiers(EDFA) and Thulium Doped Fibre Amplifiers (TDFA). Such transmission has limitations namely chromatic dispersion and nonlinear effects. These are overcome by designing a dispersion compensated broadband fibre optical communication link with a relatively large mode effective area (Aeff) that can reduce sensitivity to nonlinear optical effects.
Dispersion compensated broadband_optic link compries of a G.655 signal fiber and a segmented Dispersion Compensating Fiber (DCF). DCF is designed to have a negative dispersion coeffcient that can cancel the dispersion accumulated by signals propagating through G.655 fibres. In order to cancel the accumulated dispersion of all the different signal wavelengths within the operating wavelength range by means of the same length of dispersion compensating fibre, the slope of the DCF is kept nagative (i.e. opposite to that of the G.655 fibres) and satisfying the condition Kdf=Kix where Kdf=Ddef/Sdef and Kix=Dix/Six being the dispersion coefficients also ensures a reasonably large Aeff and low bend loss sensitivity. Finally the design targeted achievement of a mode spot size (Wp) that is as close as possible to that of the relevant signal fiber.
Salient features
Average dispersion of the link is substantially reduced compared to that of signal transmission fibre alone; · DCF has mode effective area (A base(eff)) of at least 40 µm (power 2) at the center wave length of a given amplifier band (and greater than 30 µm (power 2) across the overall amplifier band), which is larger than the presently used DCF; · Reduced sensitivity to detrimental nonlinear effects; · Bend loss < 0.1 dB for a single turn of bend diameter of 32 mm for all operating wavelength ranges and within the operating limits; · Mode spot-sizes attained for these fibres are greater than that of the presently used DCF thereby ensuring relatively smaller splice-losses of these DCF's with signal transmission fibers; · Improved performance of the system carrying broadband dispersion compensated links.
Prospective Users
Internet Service Providers, Telecommunication industries
Type of Technology
Device
Keywords
Fibre, Optic, Bandwidth, Wavelength
Developed by
Prof. Thyagarajan/ Dr. K D Pande
Department
Physics
For further information please contact
Managing Director
Foundation for Innovation and Technology Transfer (FITT)
Indian Institute of Technology, Delhi
Hauz Khas, New Delhi-110016, INDIA
Tel : 91-011-26597167, 26857762, 26581013, 26597153
Fax : 91-011-26851169
E-mail : drkdpn@gmail.com
