Quasi-CW optical bistability in InSb at room temperature

We report the first observation of quasi-steady-state optical bistability in an InSb etalon at room temperature as a result of the generation of free carriers through two photon absorption of 10 μm radiation. Nonlinear tuning of the etalon through two free spectral ranges has been achieved, with bistability observed around the two cavity resonances. Switching from a low to high transmission state has been achieved in times less than 10 ns while switching in the opposite direction occurs within 50-100 ns. The experimental results have been successfully fitted to a numerical model of the device.     

A vertical monolithic combination of an InGaAsP/InP laser and a heterojunction bipolar transistor

A DH InGaAsP/InP mesa laser and a DH InGaAsP/InP mass-transport laser were successfully put together with an InGaAsP/InP heterojunction bipolar transistor in a vertical configuration. A laser threshold current as low as 17 mA and an output laser power of over 30 mW were achieved. Base injection current-controlled optical bistability and optical switching were demonstrated.     

Gigabit pulse position bistability in semiconductor lasers

The paper briefly reviews the major forms of optical bistability in active optical devices compatible for use in gigabit optical communication systems, and reports an entirely new optical bistability for the first time. Unlike previous devices, the two bistable states of the optical device are each a series of picosecond optical pulses at 1 GHz or greater repetition rates, and are distinguished by a half period temporal shift between their temporal positions in relation to a clock pulse. The bistable device is based on a gain switched semiconductor laser. Theoretical studies suggest 100-ps switching speeds might be achieved, and experimental results are reported indicating optically triggered switching times of 500 ps.     

Investigation of low power all-optical bistability in an InGaAs-InAlAs superlattice

We report investigations of optical transmission bistability in an unprocessed InGaAs-InAlAs superlattice p-i-n structure acting as a wireless self-electro-optical effect device (SEED). We have observed and compared optical and electrical bistabilities, and examined the time dependence. The switching energy turns out to be as small as 2fJμm⁻², which compares favourably with the performance of conventional silicon MOSFETs. Modeling shows that the observed hysteresis loop results from the combination of negative electro-absorption and built-in negative dynamic resistance (NDR). We finally report the computation of all-optical bistability for a p-i-n structure inserted in a Fabry-Pérot interferometer.     

Integrated optical devices of InGaAsP/InP heterojunction phototransistor and inner stripe light-emitting diode

New integrated optical devices combining an InGaAsP/InP HPT and an inner-stripe LED are proposed and their fabrication processes are described. The device functions of light amplification, optical bistability, and optical switching are demonstrated in the 1-µm wavelength region.     

Integrated optical devices of InGaAsP/InP heterojunction phototransistor and inner stripe light-emitting diode

New integrated optical devices combining an InGaAsP/InP HPT and an inner-stripe LED are proposed and their fabrication processes are described. The device functions of light amplification, optical bistability, and optical switching are demonstrated in the 1-μm wavelength region.     

Investigation Into the Integration of a Resonant Tunnelling Diode and an Optical Communications Laser: Model and Experiment

A resonant tunnelling diode has been monolithically integrated with an optical communications laser [the resonant tunnelling diode (RTD-LD)] to form a simple optoelectronic integrated circuit (OEIC) that is a novel bistable device suitable for an optical communications system. The RTD-LD was based on a ridge-waveguide laser structure and was fabricated from an InAlGaAs-InP epi-wafer grown by molecular beam epitaxy; it emitted at around 1500 nm. Voltage controlled optical-electrical switching and bistability were observed during the characterisation of the RTD-LD - useful features for a fibre-optic communications laser. Optical and electrical simulations of the RTD-LD were carried out using the circuit simulation tool PSPICE. In addition, a discrete component version of the RTD-LD was constructed which exhibited optical power oscillations, and along with the results of the simulations, gave insight into the operating principles of the monolithically integrated RTD-LD.     

Regenerative switching characteristics of a novel electrical oroptical base-controlled AlGaAs/GaAs quantum-well heterojunction bipolartransistor

A report is presented on the regenerative switching characteristics of a novel AlGaAs/GaAs quantum-well heterojunction bipolar transistor (QWHBT) with an electrically or optically controlled base grown by molecular beam epitaxy (MBE). This double-barrier QWHBT exhibits excellent electrical switching characteristics of 7 V and 0.03 A/cm² at the switching condition and 4.5 V and 3.2 A/cm² at the holding condition. When the device is operating as an optical switch, the optical base-controlled sensitivity is 6×10 ^-3 V/μW. The effects of temperature on the device performance were evaluated at 77 and 300 K. The results show that it may be used as an all-optical switch (flip-flop) for optical parallel image processing     

Strained InGaAs quantum well vertical cavity surface emitting lasers emitting at 1.3 /spl mu/m

Results on strained InGaAs quantum well vertical cavity surface emitting lasers for optical interconnection applications are reported. Fundamental mode continuous-wave lasing at wavelengths beyond 1300 nm is demonstrated at room temperature. The metal-organic vapour-phase epitaxy grown structure was processed as top p-type distribute Bragg reflector oxide-confined devices.     

Bistability and pulsations in semiconductor lasers with inhomogeneous current injection

Bistability and pulsation at microwave frequencies are observed in CW GaAs semiconductor lasers with inhomogeneous current injection. Inhomogeneous current injection is achieved with a segmented contact structure. Crucial to the understanding of the characteristics of this device is the discovery of a negative differential electrical resistance across the contacts of the absorbing section. Depending on the electrical bias condition, this negative differential resistance leads to bistability or light-jumps and self pulsations. A simple model based on conventional rate equations with a linear gain dependence on carrier density explains the observed behavior and suggests a new mechanism in inhomogeneously pumped diode lasers for light-jumps and pulsations which does not depend on the condition for the usually proposed repetitivelyQ-switching. Investigation of the switching dynamics of this bistable optoelectronic device reveals a delay time which is critically dependent on the trigger pulse amplitude and typically on the order of a few nanoseconds with power-delay products of 100 pJ. The observed critical slowing down and its origin is discussed. We also report on the characteristic of this laser coupled to an external optical cavity and we demonstrate successfully that this bistable laser can be used as a self coupled stylus for optical disk readout with an excellent signal to noise ratio.     

非线性法布里-珀罗腔的双稳态特性分析

应用传输矩阵的方法研究了垂直微腔多量子阱结构的双稳态特性,计算结果表明,分布布喇格反射器（ＤＢＲ）的高折射率介质紧挨着非线性介质（多量子阱结构）时更容易产生双稳态,我们计算了非线性法布里－珀罗腔的反射相位与入射光功率关系曲线,反射率与入射光功率的关系曲线,和作为反射镜的ＤＢＲ的对数对双稳态性质的影响等。     

A novel all-optical bistable device in a noninterferometric double p-i(ESQW's)-n diode structure

A novel all-optical bistable double p-i-n structure (p-i-n-i-p) is demonstrated. Two thin intrinsic regions made of extremely shallow quantum wells (ESQWs) allow both large electric field modulation and strong light absorption, enhancing the optical bistability. Due to the noninterferometric nature, the double p-i(ESQWs)-n structure is not sensitive to thickness fluctuation, unlike the previously reported all-optical bistable device of asymmetric Fabry-Perot cavity structure. Uniform and high performance is realized with a contrast ratio of /spl sim/2.1, a reflectivity change of /spl sim/24%, and a bistable loop width of /spl sim/75% at 1 mW optical power without external bias.     

Investigation of polarization bistability in vertical-cavity surface-emitting lasers subjected to optical feedback

Polarization bistability in vertical-cavity surface-emitting lasers (VCSELs) subject to optical feedback has been studied both experimentally and theoretically. Optical feedback is shown to reduce the width of the bistability hysteresis loop and, hence, suppress the bistability. It is also demonstrated experimentally that polarization-selective optical feedback can be utilized to eliminate VCSEL polarization switching without inducing instabilities in the device.     

Portes NOR “ picosecondes ”tout optiques mises en série et connectées par doubleur de fréquence

The elementary cell to realize an all-optical data processing is a fast optical nor gate, compatible with a massively parallel architecture and large connection capabilities. It must be stressed that bistability is not at all obligatory in this respect. We report recent investigations on picosecond all optical nor gates in II-VI compounds (namely CdSe), that enable to realize a nor gate operating without Fabry-Pérot cavity. Transient induced absorption of photons, the energy of which is close to the bandgap energy, is due to exciton screening and gap shrinkage. We consider frequency doubling to associate and cascade several gates in order to build complex boolean functions. We demonstrate that the all optical modulation remains efficient even under violet pumping (consecutive to frequency doubling). The gate switching energy is 30 λJ/cm²to get a 4/1 contrast between the up and down output states of the nor device.     

ZnS／ZnSe迭层光栅的光学双稳

本文首次报道了室温下,在脉冲Ａｒ＾＋激光作用下,具有ＺｎＳ／ＺｎＳｅ迭层光栅结构的光学双稳,双稳开关时间约为１００ｐｓ,其非线性机理可能是由材料非线性吸收引起的“带填充”效应和迭层光栅内部层间反射共同作用的结果。     

Intrinsic optical bistability in `compensated' hetero-n-i-p-isuperlattices

A scheme for intrinsic optical bistability and switching in semiconductor heterostructures is proposed. The scheme does not require any external optical or electrical elements and possesses advantages of both the self-electrooptic effect device and doping superlattices. The switching properties of the proposed device are theoretically analyzed, and conditions for bistable operation are determined     

Optical bistability in a nonlinear directional coupler

In the nonlinear directional coupler, the optical field and the nonlinear material usually interact in a spatially and temporally local fashion and the device exhibits a nonlinear transmission characteristics, but it is not bistable. In this paper, it is shown theoretically that optical bistability in the input optical power is possible for the nonlinear directional coupler if the local phase change of the optical mode propagating through tile coupler is influenced by the excitation over the whole coupler. This condition can be satisfied in a coupler based on biased-pin-diodes comprising coupled asymmetric quantum wells in the i-region, Calculations show that in this configuration, the nonlinear directional coupler can exhibit sharp switching characteristics, low switching optical powers, optical bistability or bifurcation     

New two-mode bistability in an asymmetric absorptive multisectionlaser diode: theoretical analysis

A novel two-mode bistable laser diode (TMBLD) with an asymmetric cavity configuration is proposed and analyzed. It consists of a gain region, a saturable absorber region, and a set of mode-selective mirrors (or filters). These elements are arranged such that the saturable absorber acts as an intracavity loss for one mode and a bleachable absorber external to the cavity of the other mode. Both modes share the same gain medium and compete for the same gain. Bleaching of the absorber leads to a switching of the modes and possible bistability. This two-mode bistability results from the complementary processes of mode competition in the gain section and the mode-dependent effective cross section of the saturable absorber. A rate equation analysis of the device indicates that a switching time less than 200 ps and a modulation rate over 3 Gb/s should be obtainable     

垂直腔的光场调控及其应用（特邀）

垂直腔是激光器、探测器、滤波器、传感器等器件的核心结构,垂直腔的光场分布对激光器、滤波器、传感器等的性能具有重要的影响。垂直腔的结构影响垂直腔的光场分布,从而影响基于垂直腔的器件设计、制作以及其性能。近年来,人们围绕垂直腔的构建及其光场调控做了大量的研究,在理论基础以及器件应用等方面取得了显著进展。首先,介绍了传统上/下分布布拉格反射镜垂直腔的色散特性,和其光场调控的方法以及它们在激光器和滤波器等领域的应用;其次,介绍了基于一维和二维高折射率差亚波长光栅基复合腔的色散特性,和它们在新型激光器和单片集成多波长滤波器阵列等领域的应用;最后,对文章进行总结并展望了垂直腔的新应用。     

Multiple-input optical control of vertical cavity surface emitting lasers using intracavity-coupled in-plane lasers

We report new experimental results demonstrating optical bistability and two-input NOR gate operation in intracavity-coupled in-plane and vertical cavity surface emitting lasers (VCSELs) fabricated from the same epitaxial material. The VCSEL (or output) section gain is controlled by separately biased in-plane laser section(s), and depending on the in-plane power output, complete quenching of stimulated emission in the VCSEL is observed. Hysteresis is present in the VCSEL output power versus in-plane laser input power characteristic, and an optical memory effect is observed in the combined device.