Ring resonator fabricated in phosphosilicate glass films deposited by chemical vapor deposition

The design and fabrication of a closed loop (ring) resonator is described. The resonator was fabricated in phosphosilicate glass films deposited by chemical vapor deposition onto oxidized silicon substrates. A channel waveguide-to-channel waveguide tapered mode directional coupler was used to transfer light from the input channel to the ring. To our knowledge this is the first demonstration of the use of such a coupler for coupling between channel waveguides. An analysis is presented for power distribution in the channels of the coupler, for stored, reflected and transmitted powers in the resonator and for resonator finesse. Operation of the resonator was demonstrated experimentally and finesse values of less than 3, comparable to those published elsewhere in the literature, were obtained.