A high-speed tunable optical filter using a semiconductor double-ring resonator

A high-speed tunable optical filter incorporating a semiconductor double-ring resonator was fabricated using the InGaAsP-InP material system. This device has double-ring structure, in which two ring resonators are connected in series, to achieve the widely tuning range. This device exhibits the total free-spectral range (FSR) of 13.5 nm and the crosstalk of -9.5 dB. The radii of the rings are 25.2 and 17.8 /spl mu/m, which correspond to FSRs of 340 and 425 GHz, respectively. The switching time of the device is 2.5 ns.