By utilizing a racetrack resonator topography, an on-chip mode locked silicon evanescent laser (ML-SEL) is realized that is independent of facet polishing. This enables integration with other devices on silicon and precise control of the ML-SEL's repetition rate through lithographic definition of the cavity length. Both passive and hybrid mode-locking have been achieved with transform limited, 7 ps pulses emitted at a repetition rate of 30 GHz. Jitter and locking range are measured under hybrid mode locking with a minimum absolute jitter and maximum locking range of 364 fs, and 50 MHz, respectively.

We propose and demonstrate a long-wavelength vertical cavity surface emitting laser (VCSEL) which consists of a (311)B InP-based active region and (100) GaAs-based distributed Bragg reflectors (DBRs), with an aim to control the in-plane polarization of output power. Crystal growth on (311)B InP substrates was performed under low-migration conditions to achieve good crystalline quality. The VCSEL was fabricated by wafer bonding, which enables us to combine different materials regardless of their lattice and orientation mismatch without degrading their quality. The VCSEL was polarized with a power extinction ratio of 31 dB.

Thermal lensing effect in ridge structure InGaN multiple quantum well laser diodes Envelope-function analysis of wurtzite InGaN/GaN quantum well light emitting diodesThe ultrafast carrier dynamics in InGaN multiple-quantum-well ͑MQW͒ laser diodes were investigated using a time-resolved bias-lead monitoring technique. From the optical selection rules of TE and TM polarized light, one can selectively excite and probe different valence-subband-to-conduction-subband transitions in the MQW structure with different polarized pump and probe light. The subband structure of the MQW structure of the laser diode was calculated and is verified by electroluminescence measurement. Using this technique, ultrafast valence intersubband hole relaxation processes ͑Ͻ0.35 ps͒ were found to dominate the observed carrier dynamics.

Abstract-We have developed an improved active region design for optically pumped vertical-cavity surface-emitting lasers. The design makes use of carrier-blocking layers to segment the absorber and promote uniform carrier populations in the quantum wells with pump efficiencies near 75%. A model to calculate the carrier distribution in the active region and a design methodology are presented along with a metric to describe the carrier uniformity in the quantum wells. Experimental verification of the performance improvements shows an over 50% reduction in device thresholds and an increase of 20 C in maximum operating temperatures.

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