Novel photonic switch arrays consisting of vertically integrated multiple-quantum-well reflection modulators and phototransistors: excitation absorptive reflection switch

The authors report a novel photonic switch array, the exciton absorptive reflection switch (EARS), which operates as an optical three-terminal switch with a high contrast ratio and optical gain. The device consists of vertically integrated GaAs/AlGaAs multiple-quantum-well modulators and GaAs heterojunction phototransistors, which are optically isolated and electrically connected in series with distributed Bragg reflectors. 8*8 arrays of EARS with a contrast ratio of more than 20 dB and a high optical gain were demonstrated.<>     

All-optical photonic switches using integrated inverted asymmetricFabry-Perot modulators and heterojunction phototransistors

InGaAs/GaAs(100) multiple-quantum-well-based inverted cavity asymmetric Fabry-Perot modulators are vertically integrated with GaAs/AlGaAs heterojunction phototransistors to yield all-optical photonic switches. The photonic switches using `normally on' modulator pixels exhibit an output on-off ratio of 12:1 with internal optical gain of 4 dB. The photonic switches using `normally off' modulator pixels yield similar contrast and gain, but exhibit intrinsic bistable behavior. The inverted cavity modulators employed permit utilizing the transparency of the GaAs substrate at the operating wavelength and offer advantages for fabricating large arrays for optical signal processing     

Polarization- and wavelength-insensitive guided-wave optical switchwith semiconductor Y junction

A polarization- and wavelength-insensitive semiconductor guided-wave optical switch with a Y junction is proposed. The switch exhibits a digital response with respect to current, allowing its use as a wavelength-insensitive 1×2 optical switch. The switching characteristics are analyzed by using the beam propagation method, and a design example is given. The polarization- and wavelength-insensitive switching operation has been confirmed with a fabricated GaAs/GaAlAs switch at wavelengths of 1.3 and 1.55 μm, and the on/off ratio exceeded 20 dB at an injection current of 250 mA at these wavelengths     

Spot-size converter integrated semiconductor optical amplifiers foroptical gate applications

A spot-size converter integrated semiconductor optical amplifier (SSC-SOA) was developed as a gate element in an optical switch matrix for photonic switching applications. By a selective metal-organic vapor phase epitaxy technique, a bulk InGaAsP stripe, including an active region and thickness tapered SSCs, was grown. Wavelength composition of the stripe, strain on the stripe, and electrode coverage above the SSC region were optimized. As a result, gate operation for fiber-to-fiber gain of 0 dB was achieved at a low injection current of 30 mA, and the polarization dependence of the gain was eliminated as well     

C波段GaAs PIN二极管单片单刀单掷开关

基于中国科学院微电子研究所的GaAs PIN二极管工艺,研究了一种单片单刀单掷开关.为了仿真该单片单刀单掷开关,研制开发了GaAs PIN二极管的小信号模型.在5.5～7.5GHz的频段内,开关正向导通时的插入损耗低于1.6dB,回波损耗大于10dB,开关关断状态的隔离度大于23dB.     

C波段GaAs PIN二极管单片单刀单掷开关

基于中国科学院微电子研究所的GaAs PIN二极管工艺,研究了一种单片单刀单掷开关.为了仿真该单片单刀单掷开关,研制开发了GaAs PIN二极管的小信号模型.在5.5～7.5GHz的频段内,开关正向导通时的插入损耗低于1.6dB,回波损耗大于10dB,开关关断状态的隔离度大于23dB.     

Crosstalk measurements of integrated high-speedTi:LiNbO3 Δβ-reversal switching circuits

Directional coupler crosstalk was measured at multigigahertz frequencies using an optical sampling method for improved sensitivity. At both 2- and 4-GHz switching frequency, the crosstalk in both switch states of the coupler was ⩽-19 dB for an element of a 1×4 switch array intended for time-division-multiplexing applications. The authors also report measurements of intercoupler crosstalk for this switch array     

DC to 2.5 Gb/s×4 p-i-n/HBT optical receiver array with lowcrosstalk

A multichannel optical receiver with an In_0.53Ga_0.47As p-i-n photodetector array and a monolithic transimpedance amplifier array fabricated in AlGaAs/GaAs HBT (heterojunction bipolar transistor) technology were demonstrated. Both flip-chip rear-illuminated and wire-bonded front-illuminated detector configurations were implemented. The transimpedance was 65 dBΩ, and the 3-dB bandwidth was measured to be 2.3 GHz. By using series feedback, the transimpedance gain of each cell was matched to within 0.5 dB, and the entire array operated from a single 5-V supply. A low interchannel crosstalk of less than -40 dB was measured up to a data rate of 2 Gb/s     

A 24-GHz Patch Array with a Power Amplifier/Low-Noise Amplifier MMIC

This paper presents an active patch array designed at 24 GHz. It can be used as a front-end component for a phased array. A series resonant array structure is chosen which is compact and easy excite. With 5 elements, the array proved a 12-dB antenna gain. A power amplifier and a low noise amplifier are designed on a single GaAs chip (PALNA). Bias switch is used in the PALNA, which greatly reduces the switch loss in a transceiver and increases the efficiency. 20-dB small signal gain is achieved in both power amplifier and low noise amplifier. The active patch array is built by the combination of the patch array and PALNA. The measured active gain of this antenna is 35-dB for the PA mode and 31-dB for the LNA mode. This active patch array can obtain an EIRP of 34 dBm with a total radiated power of 22dBm and a maximum PAE of 32%. To check the noise performance, we applied sources at both normal temperature and 77K (liquid nitrogen) and extracted the noise figure (3.5 dB) of the active antenna by the Y factor method. The results proved that the active antenna is working efficiently as both a transmitting and receiving antenna.     

4×4 OEIC switch module using GaAs substrate

A compact 4×4 optical switch module consisting of a monolithic 4-channel OEIC receiver chip, a 4×4 GaAs IC chip, and a 4-channel OEIC transmitter chip has been developed for the first time. The module offers good performance, without an optical loss, a bandwidth of more than 600 MHz, and a crosstalk between neighboring channels of less than -20 dB. It has a good switching and distributive performance for high speed optical input signals of 560 Mbit/s. The switch module is attractive for use in high data-rate optical communication systems, particularly in local area networks, CATV systems, and intra-office links     

X-band MIC GaAs IMPATT amplifier module

A compact (2.0 by 1.6 in), light weight (2.1 oz), microwave integrated circuit (MIC) GaAs IMPATT amplifier module having 3.6-W pulsed output power with a gain of 22.5 dB over the 9.2-9.8 GHz band has been developed for phased array radar applications. The design goal for the module was 4-W pulsed output power with 23-dB gain over this frequency band. The module has been operated over a wide range of pulse lengths (200 ns-50 /spl mu/s) and duty factors (0.5-40 percent) with outstanding pulse fidelity. The totally integrated module consists of three IMPATT reflection amplifier stages in cascade with input and output isolators and a transmit/receive switch. Each amplifier stage has an independent hybrid thin film constant current pulse modulator. The design considerations of the essential components for final module integration, and the microwave performance characteristics are presented.     

Uniform and high-performance eight-channel bent waveguide SOA arrayfor hybrid PICs

A uniform and high performance eight-channel spot-size-converter integrated SOA (SSC-SOA) array for optical switching gate applications is demonstrated. Bow-shaped waveguides are used to achieve high gain and high ON-OFF ratio switching. All channels of the fabricated eight-channel array show a high fiber-to-fiber gain of 12.7 dB, low polarization-dependent gain (PDG) of <0.5 dB, and a high ON-OFF ratio of >50 dB at a low drive current of 40 mA     

Extremely low loss 4*4 GaAs/AlGaAs optical matrix switch

A 4*4 GaAs/AlGaAs optical matrix switch with an extremely low loss of 1.6 dB has been developed. This low loss switch was achieved by layer structure modification, to reduce free-carrier absorption, reduction of plasma damage while dry etching, and an improvement in the crystal quality.<>     

Characterization of a ferroelectric liquid crystal-based time delayunit for phased array antenna applications

An experimental demonstration of a photonic time delay unit (PTDU) based on ferroelectric liquid crystal devices and Thompson polarization beamsplitters (TBSs) is presented. High signal-to-noise ratios (SNRs) (>96 dB) and optical polarization extinction ratios (ER,~40 dB) are demonstrated for the PTDU using an active noise filter technique. Using a 5 V peak square wave switch drive signal, a 70 μs switching speed is demonstrated for this PTDU that can be used in fast (e.g., 5000 beam/s) beam scanning phased array systems. A shorter switching speed of 35 μs is also observed using a high 15 V peak transitional voltage driving signal     

An Active 60-90 GHz Single Pole Double Throw Switch MMIC

This paper introduces an active millimeter-wave switch in a GaAs metamorphic high electron mobility transistor (mHEMT) technology. The active switch exhibits broadband performance (60 to 90 GHz, 40%), a gain of 10 dB with flat frequency response and average noise figure of 2.8 dB. The unilateral receiver topology is dedicated to radiometry applications. The design combines two input-matched low noise amplifiers with an output capacitance compensation network. The switch consumes 28 mW.     

Carrier-injection type optical S3 switch withtraveling-wave amplifier

A carrier-injection-type semiconductor optical switch for photonic switching in which a traveling-wave optical amplifier is integrated in the optical single-slip structure (S³) switch to improve insertion loss and crosstalk is discussed. Preliminary experimental results are described. These results suggest that the carrier-injection-type optical S³ switch with traveling-wave amplifier has the potential to realize a small-size but large-capacity optical switch array for photonic switching     

用于电子战系统的微波光链路

微波光链路利用光纤实现信号的分发、传输和处理,它具有带宽大、重量轻、抗干扰等优点,在相控阵、多波束形成等电子战系统中具有很好的应用前景。但是其噪声系数、动态范围等方面的劣势也限制了其实际工程应用。文章主要从理论上分析了微波光链路的噪声系数、动态范围性能的限制因素。并通过试验测试给出了在现有工艺水平条件下微波光链路可以达到的性能指标:在1GHz瞬时带宽下动态范围大于40dB,噪声系数小于5dB。     

High-linearity 208-MS/s photonic analog-to-digital converter using1-to-4 optical time-division demultiplexers

This letter describes a demonstration of a photonic analog-to-digital converter operating at 208 MS/s and utilizing phase-encoded optical sampling to achieve an 87-dB two-tone third-order intermodulation-free dynamic range. A pair of LiNbO₃ 1-to-4 optical time-division demultiplexers with >35-dB channel extinction distribute the 30-ps sampling pulses to an array of photonic integrate-and-reset circuits followed by 12-b 52-MS/s electronic quantizers. Interleaving spurs due to temporal crosstalk currently limit the overall spur-free dynamic range to 65 dB     

Suppressed modal interference switches with integrated curvedamplifiers for scaleable photonic crossconnects

A novel, compact optical switch that incorporates two 1×2 suppressed modal interference (SMI) switches with an integrated curved amplifier is demonstrated as a basic component for scaleable, lossless photonic crossconnects. The basic operation of the switch is described and measured on/off ratios of 22 dB (16 dB) are reported for the cross (bar) state with switching currents of less than 25 mA per section. Lossless switching was attained in the amplified cross state, while only 0.5 dB of excess loss was measured in the unamplified bar state. Cascading of these elements should lead to N×N lossless, optical crossconnects with crosstalk levels near 40 dB     

Integration of 1024 InGaAsP/InP optoelectronic bistable switches

A photonic parallel memory (PPM), which is an array of 32×32 optoelectronic bistable switches, is discussed. The switch consists of a heterojunction phototransistor (HPT) and a light-emitting diode (LED). Optical positive feedback from LED to HPT is the cause of bistability. The PPM can be written in and read out with 1-kb parallel optical signals. The PPM has been fabricated and memory operation has been demonstrated as expected. Dissipation current for a single switch and the input optical power necessary to turn on the switch were 600 μA and 20 μW, respectively. A light pulse with a width of 5 ns was able to turn on the switch, and the product of turn-on power and pulsewidth for the short pulse region was 1.5 pJ