Apodized filters on InP-material ridge waveguides using sampled Bragg gratings

摘要

We present here the design, fabrication and first measurements of integrated Bragg grating apodized filters, operating at a free-space wavelength of about 1550 nm, based on InP material line ridge waveguides. Their apodized transmission spectra are obtained by the mean of sampled grating structures. The fabrication process by means of electron beam lithography will be described. It has been used to realize the sampled gratings which are spatially localized on the wafer. The transmission spectrum of the filters is measured. The transmission dip is almost -30 dB over almost 0.25 nm which is in a good agreement with theoretical calculations. The suppression is better than 20dB outside a bandwidth of almost 1nm, whereas a uniform grating with the same dimensions only presents almost 10dB suppression outside the same bandwidth.