Optical Filter Switchable Between Bandstop and Bandpass Responses in SOI Wafer

An optical filter switchable between bandpass and bandstop responses is proposed by analyzing frequency response in the complex plane. The device is fabricated based on silicon-on-insulator wafer. Experimental results show that the bandstop response has an extinction ration of exceeding 62.5 dB and a full width at half maximum (FWHM) bandwidth of 971 MHz, and the bandpass response has a rejection ration of 19.5 dB and a FWHM bandwidth of 840 MHz, respectively. The device also exhibits good tunability for both bandstop and bandpass responses.