Loss equalisation technique using carbon cluster-doped polyimide film and its application to 32-channel optical wavelength selector module

A novel loss equalisation technique has been developed based on the use of a carbon cluster-doped thin polyimide film which has a flat monotonic absor ption coefficient in the 1.55 mu m band. The use of this film enables the o ptical loss of individual channels to be adjusted by changing the film thic kness. By inserting this film into a groove formed in a planar lightwave ci rcuit (PLC), the authors have been able to reduce the optical loss deviatio n in a high-speed optical wavelength selector module to similar to 1.5dB.