HIGH-SPEED TUNABLE FILTER FOR ALL-OPTICAL WDM NETWORKS

BECAUSE OF THE DISCOVERY OF ER-DOPED FIBER AMPLIFIER (EDFA), THE USE OF OPTICAL FIBERS OPTIMIZED FOR 1550 NM IN TELECOMMUNICATION NETWORKS IS GAINING FAVOR AS A METHOD OF ADDING CAPACITY, PROVIDING LONGER COMMUNICATION LINKS, AND SYSTEM ECONOMY. FOR SIMILAR REASONS 1550 NM SYSTEMS ALSO ARE BEING CONSIDERED FOR NEW LOCAL EXCHANGE NETWORKS INTENDED TO ADD ROUTING DIVERSITY TO HIGH-SPEED COMPUTER NETWORKS. WITH THESE ALL-OPTICAL NETWORKS, THE SOON-TO-BE-REACHED ELECTRONICS SPEED BOTTLENECK WHICH USES TIME-DOMAIN PARTITIONING CAN BE AVOIDED. SINCE THE BANDWIDTH, OR THE INFORMATION CARRYING CAPACITY OF ER-DOPED FIBER AMPLIFIER (EDFA), IS ABOUT 30 NM AT 1550 NM, WAVE-LENGTH-DIVISION MULTIPLEXING CAN FIT 150, 0.1 NM CHANNELS WITHIN THIS BANDWIDTH (NUMBER OF CHANNELS=FINESSE/2). TO TAKE ADVANTAGE OF THIS EDFA CAPACITY, THERE IS A NEED FOR AN INEXPENSIVE, HIGH-SPEED WIDE RANGE TUNABLE OPTICAL FILTER. AN OPTICAL TUNABLE FILTER FOR OPTIMALLY TAKING ADVANTAGE OF WAVELENGTH-DIVISION MULTIPLEXING IN THE PHOTONIC-NETWORK WHICH HAS HIGH THROUGHPUT, LARGE TUNING RANGE, HIGH RESOLUTION, AND HIGH MODULATION SPEED IS BEING INVESTIGATED.