Numerical Investigation and Design of Electrically-Pumped Self-Pulsing Fano Laser Based on III-V/Silicon Integration

A self-pulsing III-V/silicon laser is designed based on the Fano resonance between a bus-waveguide and a micro-ring resonator, partially covered by the graphene as a nonlinear saturable absorption component. The Fano reflector etched on the straight waveguide is used as one of the cavity mirrors in the coupling region to work with the graphene induced loss and nonlinearity to achieve pulsed lasing in GHz repetition frequency. The detailed lasing characteristics are studied numerically by using the rate equation and finite-difference time-domain (FDTD) simulations. The results show that the CMOS compatible hybrid laser can generate picosecond pulses with repetition rate at 1~3.12 GHz, which increases linearly with the injection current.

Narrow-Linewidth GaN-on-Si Laser Diode with Slot Gratings

This letter reports room-temperature electrically pumped narrow-linewidth GaN-on-Si laser diodes. Unlike conventional distributed Bragg feedback laser diodes with hundreds of gratings, we employed only a few precisely defined slot gratings to narrow the linewidth and mitigate the negative effects of grating fabrication on the device performance. The slot gratings were incorporated into the ridge of conventional Fabry-Pérot cavity laser diodes. A subsequent wet etching in a tetramethyl ammonium hydroxide solution not only effectively removed the damages induced by the dry etching, but also converted the rough and tilted slot sidewalls into smooth and vertical ones. As a result, the threshold current was reduced by over 20%, and the reverse leakage current was decreased by over three orders of magnitude. Therefore, the room-temperature electrically pumped narrow-linewidth GaN-on-Si laser diode has been successfully demonstrated.

Study of a sub-wavelength scale plasmonic traveling wave amplifier with electrically pumped multiple quantum wells

We propose a hybrid gap plasmonic traveling wave amplifier (TWA) with electrically pumped multiple quantum wells (MQW). This TWA has deep sub-wavelength mode field scale and works at 1310nm window. For the polarization-independent amplification we design the InGaAlAs tensile-strain MQW. And we analyze this plasmonic TWA’s optical, electrical and thermal characteristics by finite element method. First we get the suitable trade-off point between the affordable mode propagation loss and moderate mode field size by adjusting the gap width and height. Second we find that the narrower the MQW, the higher the MQW local gain. Third, our device has good thermal performance as the plasmonic wave power is less than 5μw. Simulation results suggest that the independent polarization gain appears at 1317nm wavelength. And at this wavelength 3.60/cm mode gain and 161nm mode width are obtained as the 9.39kA/cm^2injection current and 10nm×240nm gap size.