We demonstrate optical bistability in InP/InAlGaAs multi-quantum well(MQW) semiconductor ring lasers(SRL) which
are fabricated by the use of inductively coupled plasma reactive ion etching (ICP-RIE) and can be used in a multi-ring to
achieve all-optical storage. Unlike other international reports, the observed optical bistability has unidirectional regime
started directly from the threshold, skip the first two regimes and greatly reduce the injection current required in
applications. The device described in this article achieves threshold current 56mA which is quite low compared to other
reported devices, and some analysis and experiments on the etching depth have been done.
Silicon photodetector can be integrated with all kinds of Silicon circuits to get monolithic OEIC. A CMOS-process-compatible silicon double-photodetector with structures of P+/N-well and N-well/P-substrate, called PD1 and PD2 respectively, is designed in this paper. The theoretical absolute spectral response and response speed of this double-photodetector are calculated and analyzed. Simulation results in 0.5um standard CMOS process show that the responsivity of the double-photodetector is above 0.2A/W from 400 to 900nm wavelength range without ARC (Anti-Reflection-Coating). Both the effects of the insulated medium layers (SiO2 and Si3N4) in CMOS process and reverse voltage on spectral responsivity are also discussed. When the optical window area is 16.54μmx16.54μm2, the capacitance of PD1 is about 100fF at a reverse voltage of 2.5V. Yet the capacitance of PD2 is almost 1/10 of PD1. With a load-resistor of 50Ω, the response speeds of PD1, PD2 and double-photodetector are 0.628, 2.04 and 2.05ns at 650nm wavelength (corresponding bandwidth about 276MHz, 85MHz and 84.7MHz), respectively. Finally, the co-design of Monolithic OEIC is also discussed. A full CMOS monolithic OEIC for optical-disc signal pickup is designed with this double-detector.
Model is developed for the dc I-V characteristics and microwave small-signal parameters of the InP-based In0.52Al0.28As/In0.65Ga0.35As HEMT’s based on physical principles, and the effect of the extrinsic source and drain resistances has also been included. Using the parameters obtained by this model and the small-signal model of PIN detector, we simulated the transimpedance configurations with an inverter and a cascode input circuit of monolithically integrated PIN-HEMT front-end optical receiver. The results indicate that the cascode input stage can realize a smaller input capacitance than the inverter-type, so it has a wider bandwidth. In order to operate in 2.5Gb/s transmission system, the cascode input stage is applied and the parameters are optimized. The simulations reveal that the transimpedance gain is larger than 63.2dBΩ and the sensitivity is 30dBm when the bit rate is 2.5Gb/s. The results obtained in this paper provide a guideline for the fabrication of PIN-HEMT optical receiver.