170 GHz Uni-Traveling Carrier Photodiodes for InP-based photonic integrated circuits.

We demonstrate the capability of fabricating extremely high-bandwidth Uni-Traveling Carrier Photodiodes (UTC-PDs) using techniques that are suitable for active-passive monolithic integration with Multiple Quantum Well (MQW)-based photonic devices. The devices achieved a responsivity of 0.27 A/W, a 3-dB bandwidth of 170 GHz, and an output power of -9 dBm at 200 GHz. We anticipate that this work will deliver Photonic Integrated Circuits with extremely high bandwidth for optical communications and millimetre-wave applications.

High-speed photodiodes for InP-based photonic integrated circuits.

We demonstrate the feasibility of monolithic integration of evanescently coupled Uni-Traveling Carrier Photodiodes (UTC-PDs) having a bandwidth exceeding 100 GHz with Multimode Interference (MMI) couplers. This platform is suitable for active-passive, butt-joint monolithic integration with various Multiple Quantum Well (MQW) devices for narrow linewidth millimeter-wave photomixing sources. The fabricated devices achieved a high 3-dB bandwidth of up to 110 GHz and a generated output power of more than 0 dBm (1 mW) at 120 GHz with a flat frequency response over the microwave F-band (90-140 GHz).

146-GHz millimeter-wave radio-over-fiber photonic wireless transmission system.

We report the experimental implementation of a wireless transmission system with a 146-GHz carrier frequency which is generated by optical heterodyning the two modes from a monolithically integrated quantum dash dual-DFB source. The monolithic structure of the device and the inherent low noise characteristics of quantum dash gain material allow us to demonstrate the transmission of a 1 Gbps ON-OFF keyed data signal with the two wavelengths in a free-running state at 146-GHz carrier wave frequency. The tuning range of the device fully covers the W-band (75 - 110 GHz) and the F-band (90 - 140 GHz).

Wavelength conversion of 1.53-microm-wavelength picosecond pulses in an ion-implanted multiple-quantum-well all-optical switch.

An ultrafast high-contrast all-optical switch produced from a metal-organic vapor phase epitaxy-grown wafer incorporating a 50-period InGaAsP/InGaAsP multiple-quantum-well (MQW) saturable absorber (SA) and a distributed Bragg reflector is described. Postgrowth implantation with 4-MeV nitrogen ions reduces the MQW free-carrier lifetime, and hence the switch recovery time, to 5.2 ps. Incorporation of the MQW SA in an optical cavity results in switching contrast ratios greater than 10 dB. The all-optical switch is used to perform wavelength conversion of 2-ps pulses.

Optical injection locking and phase-lock loop combined systems.

Optical injection locking and optical phase-lock loops have been used for laser synchronization. The use of a combined optical injection locking and phase-lock loop system is proposed here. We have taken into account the modification of the slave laser phase response induced by the injection locking to calculated the phase-error signal spectrum and the phase-error variance for an optical injection locking and phase-lock system. They show that this system presents both a wide locking range, given by the optical injection locking action, and a low phase error for low frequencies, given by the optical phase-lock loop action. These results can improve the system tracking capability and decrease the final phase-error variance compared with those in isolated systems.

Increased amplifier spacing in a soliton system with quantum-well saturable absorbers and spectral filtering.

The spacing between optical amplifiers in a long-haul soliton system may be increased to 100 km by using only passive quantum-well saturable absorbers and narrow-band filters for soliton control. After transmission over 9000 km at 10 Gbits/s, the effects of soliton-soliton interaction and Gordon-Haus jitter in the proposed systemyield bit error rates of better than 10(-9).