基于薄膜滤光片的新型可重构光分插复用器

研制了一种基于窄带薄膜滤光片的可重构的光分插复用器(ROADM).它由三个单芯光纤准直器、一对三端口光环形器、一对全反射镜和一片特别设计的角度调谐窄带多腔薄膜滤光片组成.通过步进电机的推动调制角度调谐滤光片的倾斜入射角度,从而实现了可选择波长上下路.对该可重构的光分插复用器进行了实验研究,并对该器件的串扰特性进行了详细的分析与计算.实验中得到的上下路信道隔离度大于34 dB,可调谐范围大于26nm,与理论计算结构相符.该种新型的ROADM具有结构简单、可调谐范围大、隔离度高、低偏振相关损耗、成本低等特点,可广泛应用于各种密集波分复用(DWDM)光网络.     

Design and Fabrication of Micromechanical Optical Switches Based on the Low Applied Voltage

A micromechanical optical switch driven by electrostatic was fabricated with (100) silicon and tilted 2.5°(111) silicon. The pull-in voltage is 13.2V, the insertion loss is less than 1.4dB, the crosstalk is less than -50 dB.     

Multi-degree ROADM based on wavelength selective switches: Architectures and scalability

Multi-degree implementations of the reconfigurable optical add-drop multiplexer (ROADM) are analyzed in terms of in-band crosstalk performance with an emphasis on the reduction in the number of wavelength selective switches used in the module. It is shown experimentally that an 8-degree ROADM using the wavelength selective switches for channel adding and optical splitters for channel dropping performs closely to one that uses switches for both operations. A new modular architecture based on the wavelength selective switches is proposed for implementations applicable to large degree nodes. Performance analysis of this architecture indicates node scalability to 256 degree with crosstalk-induced power penalties below 0.5 dB.     

Opto-VLSI-based tunable photonic RF filter

In this paper, an Opto-Very-Large-Scale-Integrated (Opto-VLSI) based tunable photonic radio frequency (RF) filter structure is proposed and numerically simulated. The structure comprises a reconfigurable Opto-VLSI processor capable of arbitrarily steering optical beams of different wavelengths, a diffraction grating for wavelength division demultiplexing, and high-dispersion fibres for true-time delaying RF-modulated wavebands. The proposed structure has the ability to generate arbitrary wavebands and weights for realizing any RF filter responses. The proof-of-concept of the tunable photonic RF signal processor is also experimentally demonstrated by tuning its free-spectral range and altering its shape factor through optical beam steering.     

High-speed optical bit-pattern recognition employing fibre Bragg grating and Opto-VLSI processing

We propose a novel optical bit-pattern recognition employing an Opto-VLSI processor in conjunction with an array of fibre Bragg gratings (FBGs) with different Bragg wavelengths and a coherent-to-incoherent light converter. The FBG array slices the spectrum of the incoherent optical header and provides wavelength-dependent time delays, whereas the Opto-VLSI processor generates wavelength intensity profiles that match specific bit patterns. The recognition of 8-bit optical patterns is experimentally demonstrated at 2.2 Gb/s by showing that the correlator produces an autocorrelation waveform of high peak whenever the input bit pattern matches the wavelength intensity profile.     

Novel optic-fiber switches based on the wobble-type MEMS electromagnetic microactuator

Some novel optic-fiber switches based on an MEMS electromagnetic microactuator are developed in this paper and their design, fabrication and performance are described. A new kind of wobble-type MEMS electromagnetic microactuator is successfully developed, which can drive mirrors to enter or leave the optical path of a switch. It is layered, composed of two stators and one wobble disc, which improve the output torque of the actuator. Finally, 1×2, 2×2, 1×4 and 1×8 single mode optic-fiber switches, which have been fabricated, are measured. The operating voltage is less than 8 V, switching time is less than 5 ms, insertion loss is less than 0.8 dB, crosstalk is 60 dB, and extinction ratio is 60 dB. These optic-fiber switches show a promising future in optical fiber communication systems.     

Polymeric Multimode Interference Mach–Zehnder Interferometer Electro-Optic Switch Using Embedded Coplanar Waveguide Electrode: Theory,Design, and Analysis

Abstract

The self-imaging theory is improved for designing a polymer multimode interference Mach–Zehnder interferometer electro-optic switch. The electro-optic overlap factor is enhanced from 0.6510 to 0.9658 through adopting an embedded coplanar waveguide electrode. Considering the mode dispersion effect, formulations of time-domain response are derived, and switching characteristics are analyzed. The total device length is about 7.175 mm, the switching voltage is 2.622 V, and the switching time is 29.90 ps. The lightwave 3-dB bandwidth is 20 nm, the insertion loss is less than 2.70 dB, and the crosstalk under cross and bar states are less than ?55 dB and ?45 dB, respectively.     

聚合物微环电光开关的模拟和优化

利用耦合模理论、电光调制理论和微环谐振理论,提出一个完善合理的聚合物微环电光开关的器件模型,并给出了可用以分析微环谐振过程的光强传递函数,据此在谐振波长1 550 nm下对该器件进行了模拟和优化.结果表明：微环波导芯截面尺寸为1.8×1.8 μm2,波导芯与电极间的限制层厚度为1.1 μm,电极厚度为0.15 μm,微环半径为15.2 μm,微环与信道间的耦合间距为0.16 μm,光绕微环转300 圈即可形成稳定的谐振状态,此时的谐振时间约为147.4 ps.不加电压时,下信道的插入损耗约为0.8 dB,上信道的串扰约为－26 dB;当取工作电压等于19.7 V为开关电压时,上信道的插入损耗约为0.34 dB,下信道的串扰约为－20 dB.     

一种有效提高薄膜滤光片型密集波分复用器器件性能的方法及其实验研究

对光梳状滤波器加薄膜滤光片型模块制作密集波分复用器(DWDM)的两种应用方案进行了研究,提出了一种提高插损一致性、信道隔离度及减小串扰的结构方案。对新结构方案与常规结构方案进行了理论分析及实验研究,结果表明新结构可将级联次级峰由大于-30dB降至-50dB以下。用16波50GHz的密集波分复用器件拼接进行的实验表明最终器件的插损减小0．869dB,插损一致性减小2．005dB,相邻信道隔离度提高1．004dB,非相邻信道隔离度提高42．903dB．总串扰提高1．68dB。该方案不仅可以应用到光梳状滤波器与薄膜滤光片型模块拼接高性能的超密集波分复用器件．同样也可适用于阵列波导光栅等类型的密集波分复用器件中以降低工艺难度,提高性能指标。     

Novel optical add-drop multiplexer based on dual racetrack resonators

In this paper, we designed and fabricated a four-channel optical add-drop multiplexer (OADM) based on dual racetrack resonators. The size of the fabricated device is only 2400 μm × 500 μm. The fabricated device can effectively and perfectly realize the signals upload and download. The free spectral range (FSR) of OADM is about 15.2 nm. We take the spectral responses near 1555 nm as an example. When the device acts as an optical drop multiplexer, the minimum insertion loss is 4.481 dB and the maximum extinction ratio is 31.931 dB. The maximum adjacent channels crosstalk is -9.845 dB. When the device acts as an optical add multiplexer, the minimum insertion loss is 0.944 dB and all of the extinction ratios are bigger than 25 dB. The maximum crosstalk is -16.531 dB which indicates the crosstalk can be neglected.     

一种定向耦合器型高聚物光开关设计

本文提出了一种基于定向耦合器型的高分子聚合物波导光开关设计,其突出特点是极低的波长相关性和耦合区几何尺寸敏感度,可采用橡胶成型工艺(Rubber Molding Process)实现高聚物波导在硅基底上的快速转印成型.利用BPM方法进行了器件的波导结构设计及性能模拟,插入损耗为0.4-0.6 dB,串扰<-32 dB,偏振相关损耗约为0.08 dB,电光系数r33＝14 pm/V时,器件的开关电压为42 V.     

Simulation and optimization of a polymer directional coupler electro-optic switch with push-pull electrodes

Structural model and design technique are proposed for a polymer directional coupler electro-optic switch with rib waveguides and push-pull electrodes, of which the electric field distribution is analyzed by the conformal transforming method and image method. In order to get the minimum mode loss and the minimum switching voltage, the parameters of the waveguide and electrode are optimized, such as the core with, core thickness, buffer layer between the core and the electrode, coupling gap between the waveguides, electrode thickness, electrode width and electrode gap. Switching Characteristics are analyzed, which include the output power, insertion loss, and crosstalk. To realize normal switching function, the fabrication error, spectrum shift, and coupling loss between a single mode fiber (SMF) and the waveguide are discussed. Simulation results show that the coupling length is 3082 μm, push-pull switching voltage is 2.14 V, insertion loss is less than 1.17 dB, and crosstalk is less than −30 dB for the designed device.     

Polymer waveguide thermo-optic switches with −70 dB optical crosstalk

To reduce the crosstalk of the polymer waveguide optical switches, waveguide attenuators are integrated with the switch on the same substrate. The switch and attenuator shares a single connected electrode which is controlled by a single current source. Due to the simple structure of the integrated attenuator, the device length is reduced to 10 mm so as to provide low insertion loss of 0.8 and 1.1 dB for 1300 and 1550 nm, respectively. Further radiation of the remained optical signal on the switch-off branch is induced by the integrated attenuator so that the switching crosstalk is reduced to −70 dB with an applied electrical power of 200 mW. The low crosstalk is maintained for the environmental temperature range of −10 to 55 °C.     

High-speed compact silicon digital optical switch with slot structure

A high-speed compact silicon digital optical switch (DOS) is proposed in this paper. The direct electro-optic effect is applied by filling electro-optic polymer in the void slot of the branches, which compensates the limitation of silicon itself. The crosstalk of about 35 dB and the insertion loss of 0.7 dB is obtained, the switching speed is less than 1 ps, and the whole device length can be shortened to 616 μm even using the basic mode-evolving principle and a simple Y-type structure. Analysis also shows that the device has good fabrication tolerance and wavelength independence over the C-band.     

Active semiconductor optical switches with blue-shifted channel waveguides

This paper presents a theoretical design study of active optical switches constructed from III-V semiconductor multiple-quantum-well waveguides. New designs are given for 4 × 4 matrix switches, 1 × 4 tree switches, and 4-delay optical transversal filters. The designs feature ～ 0 dB insertion loss and ～ 30 dB crosstalk isolation. Low injection currents are predicted because pumping is eliminated on ～ 70 percent of the channel waveguide area by an induced-disorder treatment that blue-shifts the material's absorption edge. The active networks also feature etched facet reflectors that facilitate the dense packing of guides.     

Fault-tolerant polarization-insensitive photonic delay line architectures using two-dimensional digital micromirror devices

A binary multichannel photonic delay line (PDL) module is introduced that gives balanced loss switched states and a polarization-insensitive operation via the use of binary operation Digital Micromirror Devices (DMDs). Experimental demonstration of a DMD-based PDL architecture is performed for a 6.84-ns time delay design. Experimental results include a 25-beam feed interchannel crosstalk test indicating a <−60 dB optical interchannel crosstalk level for a 0.381 mm interchannel distance in the multichannel PDL. An average optical signal-to-leakage noise ratio of 35.33 dB is measured for this PDL. A butterfly design PDL optical architecture is proposed for minimizing loss and improving assembly accuracy. These DMD-based variable PDLs can be used in applications ranging from radio frequency (RF) fiber-optic signal processing systems to adaptive optics for astronomical and laser radar arrays.     

Systematic investigation of silicon digital 1×2 electro-optic switch based on a microdisk resonator through carrier injection

We perform a systematic investigation on the silicon digital 1×2 electro-optic switch based on a microdisk resonator with the refractive index tuned by carrier injection and extraction. Analytical expressions are proposed to quantify the crosstalk, insertion loss and switching time, and then they are used to analyze the effect of the coupling-in/out coefficient, internal loss, and quality factor. Both electron beam lithography and photolithography were employed to construct the asymmetrically coupled microdisk resonator integrated with a p-i-n diode. A high-performance switch has been demonstrated with a crosstalk of less than −20 dB, a switching time of ∼2 ns, as well as a power consumption of 0.46 mW. Moreover, the switching of optical signals with high data rates has been characterized and analyzed under different working conditions.     

Analysis of polymer electro-optic microring resonator switches

The structure and the principle for the polymer electro-optic microring resonator (MRR) switch are proposed as well as the transfer functions. The structural parameters are optimized; the transmission characteristics are analyzed including the output power, switching time, switching voltage, insertion loss, and crosstalk. When the operation voltage is 0 V, the insertion loss and crosstalk are ∼1.2 and −20.2 dB, respectively; when the operation voltage is 10.0 V, those are ∼0.35 and −20.0 dB, respectively. Furthermore, a novel method is presented for analyzing time-domain response of the device and the switching time is determined to be ∼10.71 ps. These results indicate the favorable switching functions of the designed device.     

Active semiconductor optical switches with blue-shifted channel waveguides

This paper presents a theoretical design study of active optical switches constructed from III-V semiconductor multiple-quantum-well waveguides. New designs are given for 4 × 4 matrix switches, 1 × 4 tree switches, and 4-delay optical transversal filters. The designs feature ∼ 0 dB insertion loss and ∼ 30 dB crosstalk isolation. Low injection currents are predicted because pumping is eliminated on ∼ 70 percent of the channel waveguide area by an induced-disorder treatment that blue-shifts the material's absorption edge. The active networks also feature etched facet reflectors that facilitate the dense packing of guides.     

Analysis of a 1×32 polymer microring resonant wavelength de-multi/multiplexer assistant with interleave filter

A new 1×32 wavelength de-multi/multiplexer utilizing the microring resonator and interleave filter is proposed in this paper. A novel formula of transfer functions is presented, the parameters of microring are optimized, and the transmission characteristics of the system are analyzed. The channel spacing of the presented device is 0.4 nm. The analytical result shows that the crosstalk between adjacent channels can be reduced greatly and the filter response of the device can be improved by using the interleave filter. A bandwidth (3 dB) of 0.21 nm, an insertion loss less than 1.1 dB, and crosstalk below −32 dB were obtained for the optimized device. A method for compensating the manufacturing tolerances is discussed.