COMPACT ALL-FIBER WAVELENGTH DROP AND INSERT FILTER

A compact all-fibre design, comprising two identical Bragg gratings wr itten on to the arms of a fused fibre Mach-Zehnder interferometer, has been used to produce a low-loss wavelength drop and insert filter for wavelength division multiplexing/ demultiplexing applications in opti cal fibre communication systems. A prototype device has been produced which can multiplex/dimultiplex a signal centred on 1558.7nm with any other wavelength in the 1550nm transmission window with a maximum inse rtion loss of 1.0dB.