RAPIDLY TUNABLE NARROW-BAND WAVELENGTH FILTER USING LINBO3 UNBALANCEDMACH-ZEHNDER INTERFEROMETERS

We demonstrate a rapidly tunable narrowband wavelength filter using un balanced Mach-Zehnder interferometers in lithium niobate, It is design ed to switch among eight channels spaced 50 GHz apart in optical frequ ency (approximately 0.4 nm in wavelength) in less than 50 ns, The inse rtion loss is 19 dB and crosstalk is less than -22 dB, The filter cons ists of a cascade of three electrooptically tunable unbalanced Mach-Ze hnders and a feedback circuit to keep the filter centered on the desir ed wavelength.