High Linearity InP-Based Phase Modulators Using a Shallow Quantum-Well Design

Phase modulator nonlinearity is a major problem for implementing an optical phase-locked loop (OPLL) phase demodulator. In this letter, we report an improved InP phase modulator design that uses a detuned shallow multiquantum-well structure. The phase modulator shows high linearity and low optical loss. Its phase IP3 and optical loss per unit length are ~ 4 π/mm and ~ 0.9 dB/mm, respectively. This phase modulator design is thus suitable for implementing the OPLL linear phase demodulator.