Characteristics of a polymer Mach-Zehnder electro-optic switch using side-coupled series-cascaded M microrings

We design a channel-drop filter(CDF)with a linear gradient microcavity in a two-dimensional(2D)photonic crystal(PC).The model of three-port CDF with reflector is used to achieve high quality factor(Q-factor)and 100%channel-drop efficiency.The research indicates that adjusting the distance between reference plane and reflector can simultaneously influence the Q-factor due to coupling to a bus waveguide and the phase retardation occurring in the round trip between a microcavity and a reflector.The calculation results of 2D finite-difference time-domain(FDTD)method show that the designed filter can achieve the drop efficiency of 96.7%and ultra-high Q-factor with an ultra-small modal volume.     

Optimal design and characteristics analysis of a polymer electro-optic switch with seven vertical-turning serial-cou- pled microrings

A novel 1 x2 polymer electro-optic （EO） switch based on seven vertical-mining serial-coupled microrings is proposed for dropping crosstalk and obtaining fiat boxlike spectrum. The device structure, theory and formulation are presented, and the microring resonance order and coupling gaps are optimized. The switching voltage of the device for obtaining crosstalk lower than -30 dB under through state is decided to be about 1.86 V. Under the operation voltages of 0 V （drop state） and 1.86 V （through state）, the switching performance is characterized, and the output spectrum is ana- lyzed. The calculation results show that the crosstalk at through state and that at drop state are -30.2 dB and -53.2 dB, respectively, while the insertion losses are 0.86 dB and 3.18 dB, respectively. Owning to the seven serial-coupled mi- crorings resonance structure, the proposed switch reveals the favorable boxlike spectrum compared with the simple device with only one microring, and thus the crosstalk under drop state is improved from -26.8 dB to -53.2 dB. Due to the low crosstalk, this device can be used in optical networks-on-chip for signal switching and routing.     

Hybrid optical switch using passive polymer waveguides andsemiconductor optical amplifiers

Optical switching can be performed by using optical amplifiers combined with a passive waveguiding network. Recently, most of the effort in optical amplifier switch modules have been focused on monolithic switches in which the entire device is fabricated on an InP substrate together with the semiconductor optical amplifiers (SOA's). In this paper, we investigate the use of SOA's with passive polymer waveguides to make hybrid switches of varying sizes. The optical amplifiers serve dual purposes, gating the signal and amplifying the signal. Amplification is needed in order to offset the losses associated with the passive waveguide elements as well as the losses from component misalignments in the switch module. Our analysis finds the largest switch module size that can be made with the architecture used. We also calculate the maximum number of switch modules which can be cascaded in order to retain a bit-error rate (BER) under 10^-9     

Optimum design of a polymer electro-optic microring resonator switch

Novel transfer functions are presented for a polymer electro-optic microring resonator switches. The resonating process of the light in the microring is simulated using the formulas. Then the optimization of the structural parameters is performed, and the characteristics are analyzed, such as the resonance time, output spectrum, operation voltage, insertion loss and crosstalk were analyzed. The simulation results show that the designed device exhibits favorable switching functions.     

Passive electro-optic antenna using polymer material

The experimental results of a polymer microwave electro-optic antenna are reported. The device amplitude-modulates an optical input beam with a free-space propagating electromagnetic wave. By using a new dipole printed antenna, the electromagnetic energy is concentrated inside the device. An antenna factor of 168 dB/m is achieved with only 1 mum of electro-optic polymer     

In-line fibre-optic intensity modulator using electro-optic polymer

An in-line fibre-optic intensity modulator is reported that uses evanescent coupling from a fibre to a thin film of electro-optic polymer deposited onto a fiber half coupler. Modulation depths up to 16 dB and low loss (0-6 dB) have been demonstrated.<>     

基于光学偏置的聚合物电光调制器研究

分析了两种使Mach-Zehnder调制器实现光学偏置的方法,即路径非对称和折射率非对称的波导设计.采用有限差分束传播法(FD-BPM)对两种基于光学偏置的Mach-Zehnder型电光调制器进行了模拟仿真研究,仿真结果显示两种光学偏置方法均实现了在转换函数的线性区域建立工作点的目标,并且分别得到了26 dB和23 d...     

Optimal design of a high-speed polymer Mach-Zehnder interferometer electro-optic switch over 260 GHz

By using the proposed 3-D mode propagation analysis method and point-matching method, a polymer multimode interference (MMI) Mach-Zehnder interferometer (MZI) electro-optic (EO) switch is designed and optimized for enhancing the EO modulating efficiency and matching the impedance and the velocity. The designed switch possesses low driving voltages of ±1.375 V with a short EO active region length of 5 mm under 1550 nm wavelength, and the estimated cutoff switching frequency is up to 263 GHz due to the less mismatch between the lightwave velocity and microwave velocity. The 3-dB lightwave bandwidth is 60 nm, and within the wavelength range of 1520–1580 nm, the insertion loss and crosstalk are less than 6.71 and −30 dB, respectively.     

Crosstalk-enhanced polymer digital optical switch based on aW-shape

A three branch digital optical switch in polymers with a crosstalk of -30 dB is presented. Its crosstalk is insensitive to increasing heat power, which is the main advantage to ordinary DOS     

A Mach-Zehnder interferometer electro-optic switch with ultralow voltage-length product using poled-polymer/ silicon slot waveguide

By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer, we propose a kind of Mach-Zehnder interferometer (MZI) electro-optic (EO) switch operated at 1 550 nm. Structural parameters are optimized for realizing normal switching function. Dependencies of switching characteristics on the slot waveguide parameters are investigated. For the silicon strip with dimension of 170 nm×300 nm, as the slot width varies from 50 nm to 100 nm, the switching voltage can be as low as 1.0 V with active region length of only 0.17–0.35 mm, and the length of the whole device is only about 770–950 μm. The voltage-length product of this switching structure is only 0.17–0.35 V.mm, and it is at least 19–40 times smaller than that of the traditional polymer MZI EO switch, which is 6.69 V.mm. Compared with our previously reported MZI EO switches, this switch exhibits some superior characteristics, including low switching voltage, compact device size and small wavelength dependency.     

Reliability analysis of an optical ATM switch based on wavelength routing

Reliability studies of a demonstrated asynchronous transfer mode (ATM) switch with all-optical packet routing are presented. Calculations are based on available reliability data for commercial components. An additional inherent redundancy is shown to improve switch availability. Our calculation results further show that a proposed multiplane switch satisfies the general reliability requirement for switching systems.     

SS-TDMA switch matrices using optical technology

The principles and potential advantages of an optical switch matrix for use in an SS-TDMA microwave switching matrix subsystem are reviewed, and the relative merits of three optical switching techniques are compared. An INTELSAT sponsored programme is described that has demonstrated the feasibility and the problems of developing a compact, monolithic, optical switch matrix. RF performance generally exceeded that of switch matrices built using discrete microwave components. However, the switch matrix has a high insertion loss and requires temperature stabilization or compensation. To be practical, 1-3 micron of longer wavelength technology must be used.     

3/spl times/3 all-fiber routing switch

An all-fiber acoustooptic switch has been constructed from a 3/spl times/3 null fused coupler. The maximum drive power required is 4 mW, the switching time is 100 /spl mu/s and the insertion loss is less than 0.5 dB and has a cross talk of 20 dB. The switch shares the advantages of an earlier 2/spl times/2 switch but with more fiber ports, and should permit the design of compound routing arrays with fewer switching elements per channel.     

Wavelength-division-multiplexing optical switch using acoustooptic deflector

A new wavelength-division-multiplexing (WDM) optical switch using an acoustooptic deflector (AOD) is presented. This switch requires minimal hardware and is highly applicable in high-speed signal switching. Theoretical calculations based on the Gaussian beam approximation show that up to a 20 × 20 switch is possible using present technology. As a preliminary study, a 3 × 3 WDM switch is constructed. Crosstalk of this switch is found to be less than -20 dB, and a 500 Mbit/s return to zero (RZ) signal is successfully switched with a 4-μs switch access time. A large capacity switching network using this WDM optical switch is proposed.     

An optical switching and routing system using frequency tunable cleaved-coupled-cavity semiconductor lasers

A 1 × 4 optical switch based on a frequency tunable cleaved coupled cavity (C³) laser and a grating demultiplexer is demonstrated. The switch, which can easily be expanded to a generalN times Nswitch WithNas high as 13 has a 2 ns access time with negligible crosstalk between the channels.     

Waveguided optical switch in InGaAs/InP using free-carrier plasma dispersion

Waveguided optical switches using a carrier injection plasma dispersion are proposed. InGaAsP/InP four-port switches with two intersecting single-mode channel waveguides were fabricated by selective LPE and investigated at 1.5 ?m wavelength. Optical switching was observed, based on mode interference in the waveguide intersecting region.     

An InGaAs/GaAs MQW optical switch based on field-induced waveguides

A novel optical waveguide switch containing InGaAs/GaAs multiple-quantum wells (MQW) is proposed. In this structure, a large field-induced refractive index increase (0.1%) due to the quantum-confined Stark effect (QCSE) is utilized to generate electrically controllable waveguides. Switching operation of a first fabricated device has been investigated at wavelengths of about 1 μm. A crosstalk ratio of -18.8 dB and an extinction ratio of 20.9 dB was achieved at a reverse voltage of -7 V. Within an operational wavelength region of 9 nm, crosstalk was found to be less than -13 dB for both switching conditions. Further, the proposed switch structure seems to be well suited for monolithic integration with laser diodes and exhibits the potential for high-speed operation     

8/spl times/8 optical switch matrix using generalized Mach-Zehnder interferometers

We report an 8/spl times/8 strictly nonblocking optical cross connect (OXC) using multimode imaging (MMI)-based generalized Mach-Zehnder (MZ) interferometers realized in the silica-on-silicon planar waveguide system. Employing a router-selector architecture, this MMI-MZ OXC design results in a significantly smaller device than conventional directional-coupler based implementations. An average insertion loss of 6 dB and crosstalk of -34 dB, is demonstrated for the 8/spl times/8 OXC.     

LOCNET-an experimental communications system using optical routing

Experiences gained with the installation and operation of an experimental communication system are reported. The system uses distributed switching in its narrow-band part, integrating ISDN services and high-speed data communication, and a star coupler as a central device. LiNbO₃ optical switches behind the star coupler prevent line tapping. In the wideband subsystem, optical routing is used for videophone. The central device is a space-division-switching unit consisting of cascaded 4×4 LiNbO₃ switching matrices. Both the narrowband and wideband parts of the system have been operated with bit error rates less than 10^-9     

Code-based all optical routing using two-level coding

Code-based all optical routing employing a two-level-coding scheme is proposed. The first level of coding is employed to establish connections between users within a local area network; a second level of coding provides routing/interconnectivity between networks. The limitations due to physical-layer impairments, such as relative intensity noise (RIN) of the optical source, the signal-dependent shot noise, optical beat interference (OBI), and thermal noise at the receiver, which are some of the fundamental issues in the design of practical optical code division multiple access (CDMA) systems, are analyzed for the two-level scheme. The throughput in terms of "packets/time slot" offered by the scheme is also compared with that of the wavelength division multiple access (WDMA) system. The system capacity in WDMA is limited by the number of available wavelengths; optical CDMA, on the other hand, has many codes (user addresses), but the throughput is limited by multiple user interference, OBI, and RIN. System designs that overcome these effects and thereby improve the throughput are suggested.