Compact Optical Comb Generator Using InP Tunable Laser and Push-Pull Modulator

We have investigated the suitability of InP-based push-pull modulators to generate flat optical comb spectra. The residual amplitude modulation that was a consequence of driving the modulator well above its design voltage (up to 4 V
_π
) is demonstrated to have no adverse effect for the comb generation. We also demonstrate generation of a comb with spacing equal to twice the repetition rate via control of the relative phase of the RF signals.