1.5 μm phase-shift-controlled distributed feedback wavelength tunable optical filter

A 1.5-μm phase-shift-controlled distributed feedback wavelength tunable optical filter is studied. This wavelength tunable optical filter controls the transmissivity (gain) and the transmission wavelength independently by current injection. During wavelength tuning, the submode suppression ratio is large and a wavelength tuning range as wide as 120 GHz (9.5 Å) with 24.5-dB constant gain is achieved. An 18-channel wavelength selection with less than -10 dB crosstalk is expected with this filter. The effect of the light input, whose wavelength is in the sidelobe, on the transmission spectrum shape is shown