A guided-wave optical arbiter circuit

An optical waveguide circuit which can be used as an arbiter for priority allocation in data communication system is proposed. The waveguide circuit was fabricated by silica deposition and its basic performance as an arbiter was measured. The average insertion loss and the crosstalk level for a 10-port circuit was measured to be 9.8 and -26.8 dB, respectively. In obtaining a large number of fan-out on a compact substrate, it is important to provide large refractive-index difference between the core and cladding to allow for a sharp bend and to decrease the excess branching loss. The number of fan-out of about 250 is expected on a 50-mm-square substrate.