Ruediger Maestle

Free-space optical delay interferometer with tunable delay and phase.

A free-space optical delay interferometer (DI) featuring a continuously tunable time delay, polarization insensitive operation with high extinction ratios and accurate phase and time delay monitoring scheme is reported. The polarization dependence is actively mitigated by adjusting a birefringent liquid-crystal device. The DI has been tested for reception of D(m)PSK signals.

Tunable free space optical delay interferometer for demodulation of differential phase shift keying signals

With a continuously tunable free space optical delay interferometer and direct detection D(Q)PSK signals can be received at varying symbol rates or under optimized conditions. The interferometers phase is stabilized and its polarization dependence mitigated.

Optical vector signal analyzer based on differential direct detection

A versatile optical vector signal analyzer is presented. The analyzer measures phase, intensity, eye diagrams and constellations without a local oscillator. Performance is demonstrated for 112 Gbit/s PolMUX DQPSK and other signal formats.