Single-port laser-amplifier modulators for local access

We describe a single-port, reflective, waveguide modulator based on semiconductor laser amplifier technology. The single-port geometry reduces the high packaging cost associated with two-port waveguide modulators, while the internal gain of the amplifier compensates for splitting and coupling losses. A modulator with a bulk active layer showed a reflection-mode chip gain of 17 dB at /spl lambda/=1.56 μm. When driven with pseudorandom digital data at 100 Mb/s, extinction ratios of >12 dB were observed over the broad wavelength range (20 nm) needed for wavelength division multiplexed systems. Bit-error-rate tests confirmed that there was no distortion penalty, compared to a LiNbO₃ reference modulator.