Patent ID: 8406621

Claim:
A method for measuring a factor characterizing a balanced detection device, said balanced detection device including a pair of input waveguides, a pair of output waveguides respectively connected to a pair of photodiodes coupled to generate a differential output current, and an optical mixing element coupling light between the input waveguides and the output waveguides, the method comprising the steps of: a) injecting, via an optical assembly, a pair of modulated dual-port test signals in the pair of input waveguides, respectively, the dual-port test signals having a same optical power and a relative phase φ therebetween; b) measuring the differential output current of said photodiodes for values of said relative phase φ corresponding to light primarily reaching each one of the photodiodes, thereby obtaining maximized differential output currents ΔI 1 and ΔI 2 ; c) injecting, via said optical assembly, a modulated single-port test signal in a single one of the input waveguides, the single-port test signal having an optical power corresponding to four times the optical power of each of the dual-port test signals, and measuring the corresponding differential output current, thereby obtaining a single-port differential output current ΔI 0 ; and d) calculating a single-port rejection ratio SPRR corresponding to the ratio of the single-port differential output current ΔI 0 to the sum of the maximized differential output currents ΔI 1 and ΔI 2 .