MULTIWAVELENGTH TRANSMITTER WITH NO CROSSTALK FOR DWDM OPTICAL COMMUNICATION SYSTEMS

摘要

THIS INVENTION RELATES TO A MULTIWAVELENGTH LASER SOURCE (3) THAT IS USED WITH ADD-DROP MULTIPLEXERS/DEMULTIPLEXERS IN DENSE WAVELENGTH DIVISION MULTIPLEXED (DWDM) SYSTEM HAVING LARGE NUMBERS OF OPTICAL CHANNELS WITH VERY SMALL WAVELENGTH CHANNEL SEPARATION WITHOUT CROSSTALK.THE MULTIWAVELENGTH LASER SOURCE (3) COMPRISES OF TWOCAVITY FIBER LASER THAT OPERATES ON TWO ACTIVE GAIN MEDIA AND OUTPUTS AN EQUALLY SPACED MULTIPLE WAVELENGTH SIGNALS. THE CENTRE WAVELENGTH OF EACH SIGNAL DEPENDS ON THE PREVIOUS SIGNAL THAT WAS GENERATED AND ANY WAVELENGTH-SHIFT WILL CAUSE THE WHOLE SPECTRUM TO SHIFT PROPORTIONATELY AND MAINTAINED FIXED CHANNEL SPACING.THE ADD-DROP MULTIPLEXERS/DEMULTIPLEXER EMPLOY SETS OF NARROW REFLECTED BANDWIDTH FIBER BRAGG GRATINGS THAT RELIABLY ADD OR DROP OPTICAL CHANNELS.(FIG 1)