Polarization-insensitive high-speed InP/InGaAsP access node space switch matrix for bidirectional optical ATM networks

An InP/InGaAsP optical space switch matrix with 5 polarization-insensitive Mach-Zehnder interferometers in 3 stages and with 6 inputs and 6 outputs for access network applications is reported. The switches, specially designed for a low polarization dependence and low insertion losses, typically show on-state polarization-sensitivities of less than 0.5 dB, nearly identical switching voltages of around 7 V for TE and TM polarization, insertion losses below 11 dB, on-off ratios above 15 dB and high-speed switching capabilities up to 3 Gb/s.