Fabrication of wavelength-tunable InGaAsP/InP grating-assisted codirectional coupler filter with very narrow bandwidth

摘要

A wavelength-tunable grating-assisted codirectional coupler optical filter with a full coupling length of 4.5 mm has been designed and fabricated by reactive ion etching and metal organic chemical vapour deposition techniques. The centre wavelength and bandwidth for TE-polarisation were 1530.6 and 1.5 nm, respectively, and those for TM-polarisation were 1494.0 and 1.3 nm. respectively, which is one of the narrowest reported. When a current of 100 mA was injected into a lower index waveguide, the central wavelength shifted by 7.8 nm towards the longer wavelength side.