Generation of 10-Gbit/s Optical Millimeter-Wave Signal using a 125-GHz Mode-Locked Laser Diode Integrated with an Electro-Absorption Modulator

We fabricated a compact optical millimeter-wave (MMW) transmitter by monolithically integrating an active mode-locked laser diode (MLLD) and high-mesa electro-absorption (EA) modulators. From the frequency domain measurements of the 125-GHz optical MMW signal, we obtained a linewidth of less than 10 Hz and a timing jitter of 0.1 ps. As for the integrated EA modulator, a high extinction ratio (20 dB) and a large 3-dB-down bandwidth (16 GHz) were achieved by employing high-mesa waveguide structure buried with polyimide. In bit-error-rate measurements of the 10-Gbit/s MMW signal generated using the optical MMW transmitter, error-free operation was achieved.