Cu/parylene electrode type H:LiNbO/sub 3/ optical modulator

A Mach-Zehnder optical waveguide has been fabricated in z-cut LiNbO/sub 3/ substrate by employing the conventional proton exchange and annealing technique. Proton exchange and annealing temperature, and their processing time were 200/spl deg/C, 400/spl deg/C, 30 minutes and 100 minutes, respectively. About 2000/spl sim/10000 /spl Aring/ parylene-C or N layer has been deposited on the substrate. Cu (or Au) of 2000 /spl Aring/ has been sputtered on parylene buffer layer, and then CPW electrodes have been formed by traditional photolithographic process. Physical and chemical tests of parylene buffer layer deposited on LiNbO/sub 3/ and under electrodes have been performed. Parylene had good adhesion to LiNbO/sub 3/ substrate and Cu electrode. Patterning and etching of electrodes on parylene by various chemicals have been performed. For post metal process, no noticeable problems of deposited parylene films have been found. After dicing and end-face polishing of the fabricated modulator chip, optical modulation responses as sawtooth electrical driving voltage have been measured at low frequencies.