Advanced photonic devices for Telecom applications

Anticipating the needs of the Optical Telecom Network evolution, an activity on lasers for Telecom applications is carried out in the III-V Lab. This activity encompasses developments in : Quantum Dots (QD) lasers and amplifiers, mode-locked lasers, Photonic Crystals (PhC) based lasers and amplifiers, and functional semiconductor devices for all-optical signal processing.

During the past few years, self-assembled semiconductor QD lasers have attracted considerable attention, since they are expected to present lower threshold current, lower chirp, higher gain, and higher thermal stability than quantum well devices. For a 310 µm long BRS QD laser in a high reflectivity/cleaved facet configuration, the sensitivity at BER = 10-10 equals –13.5 dBm and – 9.6 dBm, with extinction ratio of 5.9 dB and 3.2 dB at 25 °C and 75 °C respectively.
QD laser diodes are attracting a great interest as they provide large lasing spectrum and fast carrier dynamics. They are perfectly suited for the generation of short pulses and for all-optical clock recovery. This figure shows the eye diagram of the incoming OTDM signal (top) and the recovered clock (bottom). A high quality clock signal with high extinction ratio (> 13 dB) is observed.
The single active layer Electro-absorption modulated Laser is a versatile source for 10 & 40 Gbit/s applications. It benefits from a large spectral and operating temperature range. This is due to the AlGaInAs structure and the automatic thermal compensation with a positive Bragg detuning, respectively.