A rotary electrostatic micromotor 1×8 optical switch

This paper describes a 1×8 rotary electrostatic micromotor optical switch fabricated using high-aspect-ratio micromachining technology to produce silicon or nickel components which are subsequently assembled to form a switch. The switch consists of a salient-pole micromotor with 1-mm-diameter 200-μm-thick rotor that supports up to a 500-μm-tall, 900-μm-wide mirror. Typical switches were actuated at 50 V, operated for extended periods in room air, and found to have a rapid rotation with an average optical switching time between two neighboring fiber ports of 18 ms. Optical testing was performed at wavelength of 1310 nm in single- and multimode, and at 850 nm in multimode. The optical beam was propagated in free space with minimal divergence through the use of externally mounted collimating gradient-index lenses. With an aluminum coating, the mirror and external optics exhibited an input to output coupling loss as low as 0.96 dB in multimode and 2.32 dB in single-mode. Interchannel crosstalk was less than -45 dB     

Reliable wide-temperature-range operation of 1.3-μmbeam-expander integrated laser diode for passively aligned opticalmodules

A novel structure for a 1.3-μm beam-expander integrated (BEX) laser diode is demonstrated. It combines a thickness-tapered InGaAsP-InP multiple quantum-well (QW) crystal grown by a novel silicon shadow masked metalorganic vapor phase epitaxy and a simple reverse-trapezoid-ridge waveguide laser structure that offers smooth mode field expansion and improved high-temperature lasing performance. We found this new BEX laser quite suitable for operation over a wide range of temperatures above 85°C and highly efficient lens-free coupling to a single-mode fiber (SMF) of less than 3 dB. These excellent lasing properties along with reliability under severe environmental conditions make this BEX-LD a promising candidate for practical use for low-cost long-wavelength light-source modules using optical passive alignment techniques     

An Optical Parametric Amplified Fiber Switch for Optical Signal Processing and Regeneration

An optical parametric amplified (OPA) fiber switch is described in this paper. This device switches input signals without shifting the wavelength by changing the polarization state of the signal using optical parametric amplification. The OPA fiber switch features ultra-broadband, highly efficient switching with a high contrast ratio. We experimentally test the prototype of the OPA fiber switch, which uses a highly nonlinear fiber. Optical demultiplexing of 160 Gb/s differential phase-shift keying (DPSK) signals is demonstrated in the whole C-band and shows that it provides almost penalty-free optical detection. The application of amplitude noise suppression with the OPA fiber switch by using parametric gain saturation is then proposed and demonstrated for a 160 Gb/s DPSK signal. When it is set to an amplitude-limiting condition, the OPA fiber switch successfully increases the optical signal-to-noise ratio by 4 dB and effectively suppresses the phase deterioration in 160 Gb/s DPSK transmission by increasing the system margin by more than 5 dB.     

Microoptical fiber switch for a large number of interconnects:optical design considerations and experimental realizations usingmicrolens arrays

The authors investigate a 1 × N free-space microoptical fiber switch for a large number of interconnects. The system to be studied is a reflective 4f optical system. Alignment tolerances and coupling efficiency are investigated and the benefit brought by collimating microlens arrays is reported (theoretically and experimentally). The use of microlenses enables power coupling efficiency between 3 and 2 dB (including losses due to the optical elements) for an optical switch allowing up to 3000 receiver fibers     

Integrated optical, wavelength selective, acoustically tunable2×2 switches (add-drop multiplexers) in LiNbO3

Fully packaged, polarization independent, integrated acoustooptic 2×2 switches have been developed which can be also used as add/drop multiplexers. The devices have been fabricated in X-cut Y-propagating LiNbO₃ and can be operated at wavelengths around 1550 nm. They consist of passive polarization splitters and acoustooptic TE-TM converters with weighted coupling. A filter bandwidth of 2.0 nm and a tuning range of 130 nm have been obtained. The fiber-to-fiber insertion loss is <4.6 dB and a residual polarization dependence of 1.3 dB for bar-state and 0.1 dB for cross-state routing has been achieved     

High-density digital free-space photonic-switching fabrics usingexciton absorption reflection-switch (EARS) arrays and microbeam opticalinterconnections

We describe a compact digital free-space photonic-switching module that uses microbeam optical interconnections based on stacked planar optics and exciton absorption reflection-switch (EARS) arrays. Microbeam optical interconnections become increasingly attractive as the number of optical input and output (I/O) ports increases because of their small size. The EARS device provides the digital-signal regeneration needed for constructing a multistage switching network. This paper mainly describes the experimental investigation of a prototype switch having a two-stage, 16-input, 16-output structure (four sets of 4×4 switches), with highly dense two-dimensional fiber array pigtails acting as high-density optical I/Os. The prototype is approximately 30×90×22 mm [60 cc]. A relay lens array inserted between stages eliminates the beam spreading caused by diffraction, which decreases the required positioning accuracy for the optomechanical packaging. Two-stage switching at a data transmission rate of 4 Mb/s has been demonstrated. Increasing the operating speed of the switch and introducing an easy assembly method to reduce assembly costs are future enhancements     

Polymeric electrooptic 2×2 switch consisting of bifurcationoptical active waveguides and a Mach-Zehnder interferometer

We interpret the modified bifurcation optically active waveguide switch structure for a polymeric electrooptic (EO) 2×2 switch. PEI-DR1, UFC150, and Resole HM2 were used as the core EO material, the lower clad material, and the upper clad material, respectively. We present the optical and electrical properties on this material system for high-performance devices. We fabricate the electrically and optically packaged polymeric EO 2×2 switch for high-speed optical communications. At an operating voltage of 8.5 V, the crosstalk of the cross-arm is -18.1 dB, and that of the straight arm is -18.5 dB. The measured optical loss is 14 dB at λ=1.3 μm. The 6-dB attenuation in radio-frequency transmission corresponds to about 17 GHz     

A novel analog switch for high‐precision switched‐capacitor applications

The performance of a switched‐capacitor circuit strongly depends on its analog switches. This paper introduces a new technique to design a high‐precision analog metal‐oxide‐semiconductor switch for switched‐capacitor applications. The accuracy of analog switches is a critical parameter to determine overall performance of the discrete‐time analog systems. To satisfy the accuracy requirements of the switch, a novel technique to minimize the charge injection and clock feedthrough errors by using a very simple structure is proposed. Moreover, an innovative approach to increase the OFF resistance of the switch and consequently minimizing its leakage current is presented. To evaluate the performance of the proposed switch, simulations are done in TSMC 0.18μm standard complementary metal‐oxide‐semiconductor technology with BSIM3V3 device models. The ON and OFF resistances of the switch are one of the most important factors that should be considered while investigating analog switches. The ON resistance of the proposed switch is less than 560Ω over entire input signal range which completely satisfies the tracking bandwidth requirements. In addition, since the proposed switch provides an ultrahigh OFF resistance in the range of several GΩs, the leakage current of the proposed switch is negligible. Simulation results also show that switch‐induced errors are significantly eliminated by using the proposed cancellation technique. The output error charge due to charge injection and clock feedthrough over a wide range of input signal variation is very low (less than 1.6 fC). Moreover, simulation results show that the proposed switch achieves signal to noise plus distortion ratio of 80.55 dB, effective number of bits of 13.08, total harmonic distortion of ?81.41 dB, and spurious‐free dynamic range of 87.7 dB for a 2.5‐MHz sinusoidal input of 800‐mV peak‐to‐peak amplitude at 200‐MHz sampling rate with a 1.8‐V supply voltage. Consequently, the simulation results verify that the proposed switch can significantly improve the dynamic and static performances of a switched‐capacitor circuit.     

Proposal of over 100‐GHz band waveguide switch

A filter bank consisting of switches and band‐pass filters is one method for configuring a spectrum analyzer preselector. A long‐life switch with high isolation is key to this development. We propose a novel horizontal‐moving waveguide switch designed for easy addition of ports compared to commercial rotating switches. The switch has a small gap between the fixed and moving parts with the gap surrounded by chokes. This configuration offers high isolation and long life. It also reduces the size of the filter bank. This paper describes 2 proposed switch prototypes for frequency ranges from 90 to 140 GHz and from 255 to 315 GHz. The measured switch isolation is better than 50 dB and the insertion loss is less than 3 dB for both prototypes.     

A 2- to 12-GHz 65-nm transmit/receive CMOS DP8T switching matrix for ultra-wideband antenna arrays

An ultra-wideband 2- to 12-GHz transmit/receive (T/R) double-pole–eight-throw (DP8T) switching matrix is developed with a 65-nm complementary metal oxide semiconductor (CMOS) process for a radar-based breast cancer detection system. The measured average insertion losses are 5.2, 7, and 10.6 dB at 2, 6, and 12 GHz, respectively, with input and output matching bandwidths of 2 to 12 GHz and a third-order input intercept point (IIP3) of 31 dBm at 8 GHz. The power consumption is less than 1 mW for a 1.2-V power supply. To the best of the authors' knowledge, this is the first reported DP8T CMOS switching matrix to replace the conventional mechanical switch to control a portable radar antenna.     

Integrated optical 2 /spl times/ 2 switch for wavelength multiplexed interconnects

A highly compact integrated optical switch is proposed and demonstrated for broadband optical switching applications. Routing of 8 /spl times/ 10 Gb/s data channels is demonstrated using a low-cost 1250-Mb/s control scheme. The advantages of lossless operation, broad optical bandwidth, and nanosecond switching times are leveraged. Multichannel wavelength is exploited for reduced latency, enhanced capacity, and functionality, while retaining compatibility with existing off-the-shelf electronics and transceiver technology. The requirements for optical header processing, wavelength translation, and optical buffering are avoided. Low-penalty multiwavelength transmission is demonstrated for a highly compact sub-mm/sup 2/ amplifying 2 /spl times/ 2 switch. Pattern dependent gain and amplified spontaneous emission are minimized to facilitate 0.0-0.4 dB penalty. Mitigation techniques compatible with the architecture are deployed to reduce the penalty under adverse operating conditions. Control schemes are proposed and demonstrated to facilitate 8 /spl times/ 10 Gb/s optically switched networking.     

POF-based interconnects for intracomputer applications

The technology and the optical characteristics of ×8 optical interconnects based on plastic optical fibers (POF's) are presented. The MT-compatible interconnects have been realized by using ribbonized 120-1125-μm multimode step index POF. Two-dimensional POF arrays with a pitch of 250 μm have been fabricated either by using precision drilled PMMA-hole-plates or by embedding the POF's in grooved copper plates and piling them up subsequently. The transmission loss of a 20 cm-long 8×8 interconnect including two 900 bends was 1.5 dB at 650 nm, 3.5 dB at 870 nm, and 4.5 dB at 980 nm     

All-silicon bistable micromechanical fiber switch based on advancedbulk micromachining

Bulk silicon micromachining is used to fabricate bistable optical fiber switches. The switches are based on a silicon device consisting of an actuator for fiber movement and a V-groove fiber clamp for bistable operation. The complete mechanical structures including thermal actuators are etched into standard 〈100〉 silicon wafers using anisotropic wet etching in KOH. While switching is caused by asymmetric thermal expansion of a U-shaped silicon cantilever, the fiber clamp is driven by the bimaterial effect. The efficient process technology allows a low cost batch fabrication of these devices. The switches exhibit an insertion loss <1 dB and a crosstalk of <-60 dB using standard single-mode fibers. A switching power below 1 W is required during switching     

根据变电站一次接线图导出闭锁公式的方法

在对变电站的断路器或刀闸进行分、合操作时,由于人员和电网等方面的安全性要求,在特定情况下需要闭锁特定断路器或刀闸的分、合操作（包括业内所称的“五防”闭锁）。同一断路器或刀闸是否需要闭锁,与变电站电网当时的运行状态有关,即与当时的电网连通状态有关。文中利用图论中图的邻接矩阵表示方法,通过对矩阵中元素的含义以及矩阵运算的含义进行适当修改,实现了对于每一特定的变电站,可以根据其一次接线图,通过规范性的步骤和方法,得到每一断路器或刀闸的分、合操作是否需要闭锁与变电站电网的连通状态的逻辑关系的静态表达式,即得到每一断路器或刀闸的分、合操作是否需要闭锁与其他断路器或刀闸的开合状态的逻辑关系的静态表达式。     

New protection issues of a matrix converter: design considerationsfor adjustable-speed drives

Induction motors are traditionally controlled by standard pulsewidth modulation voltage-source inverters. An alternative is the matrix converter, which consists of nine bidirectional switches. This converter has benefits compared to a standard inverter, like sinusoidal input current and bidirectional power flow. The main disadvantage is the lack of a bidirectional switch, because such a switch may be done by two transistors and two diodes. An important topic is protection of the matrix converter, and this paper proposes two new protection circuits for matrix converters with a reduced number of components. The number of protection diodes is reduced by six. Design expressions of the protection circuit are calculated and validated by simulation. The standard protection circuit and the new circuits are demonstrated by simulation to have the same performance. Experimental results on an 8 kVA matrix converter show the design expressions are correct. It is concluded that it is possible to reduce the necessary power components in a matrix converter     

Electromagnetic torsion mirrors for self-aligned fiber-opticcrossconnectors by silicon micromachining

We report a micromechanical fiber-optic switch (1 cm×1 cm×1 mm) based on an electromagnetically operated torsion mirror which is suitable for self-latching operation. The switch is fabricated by silicon micromachining technology, and self-alignment technique is employed to align optical fibers to the mirror. A small mirror of gold finished FeNiCo/polysilicon (150 μm×500 μm) is supported by two beams, and rotated around the axis in the magnetic field induced by an electromagnet. An incident light is redirected by the mirror in a free-space smaller than 1 mm³. Multimode fibers are used for optical coupling of small loss (-2.5 dB for reflection and -0.83 dB for transmission) at a wavelength 1.55 μm. Typical switching time is 10-25 ms, and switching contrast is larger than 45 dB. Magnetic torque and optical coupling are theoretically investigated     

Injection molded plastic multifiber connector realizing physicalcontact with fiber elasticity

We have proposed and demonstrated a fiber physical contact connector. This connector aligns multiple bare fibers in microholes individually and realizes physical contact by using the buckling force of the fibers themselves. The prototype is injection molded plastic and has a size of 7×24×3 mm for 8 fibers at a 0.25-mm pitch. The average insertion and return losses for single-mode fibers are under 0.2 dB and over 60 dB. These losses are stable in environmental tests     

Matrix combination of elementary switches: general considerations and application to MEMS relays

This paper addresses some general aspects of switching devices consisting of a parallel-series (matrix) combination of elementary switches. The discussion is aimed at the derivation of criteria, which allow judging the potential of performance up-rating under rated current and interruption conditions. The elementary switch types considered are arcing switches and novel arc-free micro-switches. The latter are studied in some more detail in comparison with experimental data.     

基于中心抽头变压器的倍频感应加热电源

针对高频大功率应用场合,提出了一种基于中心抽头变压器的倍频式感应加热电源。采用结构对称的两个半桥、共用谐振电容、抽头变压器耦合的方式,使得负载工作频率为功率开关管工作频率的两倍,达到倍频的目的。功率开关管具有软开关特性,且导通时间为其开关周期的25%,相对于传统的桥式逆变器来说,明显降低了开关管的功耗。详细分析了8个不同的工作模式及相应的系统参数关系,给出了电路参数的设计方法。最后以IGBT为功率开关管,设计了一台小型样机,通过实验验证了所提出的电源拓扑、理论分析及参数选取方法的正确性。     

1.55-μm InGaAsP-InP laser arrays with integrated-mode expandersfabricated using a single epitaxial growth

We report on two techniques for the realization of expanded-mode laser arrays with a single epitaxial growth step and conventional fabrication techniques. Laser arrays with integrated adiabatic-mode expanders (AME) based on a tapered active region and an underlying passive coupling waveguide are demonstrated at the 1.55-μm wavelength. These lasers butt couple to standard cleaved single-mode fibers (SMF's) with a loss of only 3.6 dB. This coupling efficiency compares with a theoretical calculation of 3.2 dB. We also propose a novel realization of a laser with an integrated-mode expander based on resonant coupling between a tapered active waveguide and an underlying coupling waveguide. Three-dimensional (3-D) beam propagation method (BPM) results are presented which show that compact, efficient mode expanders with a mode transformation loss of only 0.36 dB can be realized using this method. Butt-coupling efficiencies of 2.6 dB are possible to standard cleaved single-mode fibers