High-power electro-optic switch technology based on novel transparent ceramic

A novel high-power polarization-independent electro-optic switch technology based on a reciprocal structtire Sagnac interferometer and a transparent quadratic electro-optic ceramic is proposed and analyzed theoretically and experimentally. The electro-optic ceramic is used as a phase retarder for the clockwise and counter-clockwise polarized light, and their po- larization directions are adjusted to their orthogonal positions by using two half-wave plates. The output light then becomes polarization-independent with respect to the polarization direction of the input light. The switch characteristics, including splitter ratios and polarization states, are theoretically analyzed and simulated in detail by the matrix multiplication method. An experimental setup is built to verify the analysis and experimental results. A new component ceramic is used and a non- polarizing cube beam splitter （NPBS） replaces the beam splitter （BS） to lower the ON/OFF voltage to 305 V and improve the extinction ratio by 2 dB. Finally, the laser-induced damage threshold for the proposed switch is measured and discussed. It is believed that potential applications of this novel polarization-independent electro-optic switch technology will be wide, especially for ultrafast high-power laser systems.

Optimized design and fabrication of nanosecond response electro optic switch based on ultraviolet-curable polymers

A nanosecond response waveguide electro-optic （EO） switch based on ultraviolet （UV） sensitive polymers of Norland optical adhesive （NOA73） and Dispersed Red 1 （DR1） doped SU-8 （DR1/SU-8） is designed and fabricated. The absorption properties, refractive indexes, and surface morphologies of NOA73 film are characterized. The single-mode transmission condition is computed by the effective index method, and the percentage of optical field distributed in EO layer is optimized to be 93.78 %. By means of spin-coating, thermal evaporation, photolithography, and inductively coupled plasma etching, a Mach-Zehnder inverted-rib waveguide EO switch with micro-strip line electrode is fabricated on a silicon substrate. Scanning electron microscope characterization proves the physic-chemical compatibility between NOA73 cladding and DR1/SU-8 core material. The optical transmission loss of the fabricated switch is measured to be 2.5 dB/cm. The rise time and fall time of switching are 3.199 ns and 2.559 ns, respectively. These results indicate that the inverted-rib wave- guide based on UV-curable polymers can effectively reduce the optical transmission loss and improve the time response performance of an EO switch.

Strictly non-blocking 4×4 silicon electro–optic switch matrix

The first path-independent insertion-loss（PILOSS） strictly non-blocking 4×4 silicon electro–optic switch matrix is reported. The footprint of this switch matrix is only 4.6 mm×1.0 mm. Using single-arm modulation, the crosstalk measured in this test is-13 dB --27 dB. And a maximum crosstalk deterioration of 6d B caused by two-path interference is also found.

High-speed 2 × 2 silicon-based electro-optic switch with nanosecond switch time

A 2 × 2 electro-optic switch is experimentally demonstrated using the optical structure of a Mach-Zehnder interferometer （MZI） based on a submicron rib waveguide and the electrical structure of a PIN diode on silicon-on-insulator （SOI）. The switch behaviour is achieved through the plasma dispersion effect of silicon. The device has a modulation arm of 1 mm in length and cross-section of 400 nm×340 nm. The measurement results show that the switch has a VπLπ figure of merit of 0.145 V.cm and the extinction ratios of two output ports and cross talk are 40 dB, 28 dB and -28 dB, respectively. A 3 dB modulation bandwidth of 90 MHz and a switch time of 6.8 ns for the rise edge and 2.7 ns for the fall edge are also demonstrated.

Compact 2×2 parabolic multimode interference thermo–optic switches based on fluorinated photopolymer

In this work, a dual-side parabolic structural(DSPS) multimode interference(MMI) thermo–optic(TO) waveguide switch is designed and fabricated by using novel low-loss fluorinated photopolymer materials. Comparing with the traditional dual-side linear structural(DSLS) MMI device, the effective length of the MMI coupling region proposed can be effectively reduced by 40%. The thermal stability of the waveguide material is analyzed, and the optical characteristics of the switching chip are simulated. The actual performances of the entire MMI switch are measured with an insertion loss of7 dB, switching power of 15 m W and an extinction ratio of 28 dB. In contrast to the traditional MMI optical switch, the new type of parabolic structural MMI TO waveguide switch exhibits lower power consumption and larger extinction ratio. The compact fluorinated polymer MMI TO switches are suitable well for realizing miniaturization, high-properties, and lower cost of photonic integrated circuits.

A 1×4 Polymeric Digital Optical Switch Based on the Thermo-Optic Effect

We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.

Analysis and Design for a Micro Mechanical Optical Switch

The mechanical and electric characteristics of a cantilever beam micro opto mechanical switch are studied theoretically,with which the dependence of the flexion on the applied voltage is derived,as well as the formula of the threshold voltage.The applied voltage,having no connection with the width of the beam,is in inverse proportion to the square of the beam's length.The deflection at the beam's tip cannot exceed 1/3 of the distance between two adjacent electrodes.These results are the basis of the switch design and development.

Fabrication and Electromechanical Characteristics of 2×2 Torsion-Mirror Optical Switch Arrays with Monolithically Integrated Fiber Self-Holding Structures

Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct and alternating electric fields.When the thickness of the elastic torsion beams suspending the aluminum coated polysilicon micro-mirrors of the switches in the arrays is about 1μm,the electrostatic yielding voltages for driving the mirrors to achieve their ON-state are in the range of 270～290V,and the minimum holding voltages for mirrors ON-state are found as 55V or so.Theoretical analysis manifests that the yielding voltage is more sensitive to beam thickness than other design parameters do about the torsion-mirror switch structures.The lifetime can reach 10 8 times.The estimated shortest switching time of the switches at least lasts for less than 2ms.The force analysis on the two kinds of new fiber self-holding structures integrated monolithically in the chip of the optical switch arrays indicates that the structures can feature self-fixing and self-aligning of optical fibers.

A 16×16 Micro Mirror Array for Optical Switches

This paper reports on the design, fabrication,and performance of a high-reflectivity large-rotation mirror array for MEMS （micro-electro-mechanical system） 16 × 16 optical switches. The mirror in the array can enlarge its rotation an- gles up to 90° and keep a steady state to steer the optical signal. According to the large-rotation behavior, an electro- mechanical model of the mirror is presented. By monolithic integration of fiber grooves and mirrors fabricated by a sur- face and bulk hybrid micromachining process, the coarse passive alignment of fiber-mirror-fiber can be achieved. The re- flectivity of the mirror is measured to be 93.1% ~96.3%. The switches demonstrate that the smallest fiber-mirror-fiber insertion loss is 2. ldB using OptiFocusTM collimating lensed fibers. Moreover,only about ＋- 0.01dB oscillating amplitude of insertion loss is provoked after the device is tested for 15min for 5-90Hz in the vertical vibration amplitude of 3mm.

Delay-Differentiated Scheduling in Optical Packet Switches for Cloud Data Centers

We consider differentiated timecritical task scheduling in a N×N input queued optical packet s w itch to ens ure 100% throughput and meet different delay requirements among various modules of data center. Existing schemes either consider slot-by-slot scheduling with queue depth serving as the delay metric or assume that each input-output connection has the same delay bound in the batch scheduling mode. The former scheme neglects the effect of reconfiguration overhead, which may result in crippled system performance, while the latter cannot satisfy users' differentiated Quality of Service(Qo S) requirements. To make up these deficiencies, we propose a new batch scheduling scheme to meet the various portto-port delay requirements in a best-effort manner. Moreover, a speedup is considered to compensate for both the reconfiguration overhead and the unavoidable slots wastage in the switch fabric. With traffic matrix and delay constraint matrix given, this paper proposes two heuristic algorithms Stringent Delay First(SDF) and m-order SDF(m-SDF) to realize the 100% packet switching, while maximizing the delay constraints satisfaction ratio. The performance of our scheme is verified by extensive numerical simulations.

Multifunctional disk device for optical switch and temperature sensor

A multifunctional surface plasmon polariton disk device coupled by two metal-insulator-metal（MIM） waveguides is proposed and investigated numerically with finite-difference time-domain simulation. It can be used as optical switch and temperature sensor by filling disk with liquid crystal and ethanol, respectively. The simulation results demonstrate that the transmission characteristics of an optical switch can be manipulated by adjusting the radius of disk and the slit width between disk and MIM waveguides. The transmittance and modulation depth of optical switch at 1550 nm are up to 64.82% and 17.70 d B, respectively. As a temperature sensor, its figure of merit can reach 30.46. In this paper, an optical switch with better efficiency and a temperature sensor with better sensitivity can be achieved.

All-optical switching and nonlinear optical properties of HBT in ethanol solution

This paper demonstrates an all-optical switching model system comprising a single pulsed pump beam at 355 nm and a CW He-Ne signal beam at 632.8 nm with 2-（2＇-hydroxyphenyl）benzothiazole （HBT） in ethanol solution. The origins of the optical switching effect were discussed. By the study of nonlinear optical properties for HBT in ethanol solvent, this paper verified that the excited-state intramolecular proton transfer （ESIPT） effect of HBT and the thermal effect of solvent worked on quite different time scales and together induced the change of the refractive index of HBT solution, leading to the signal beam deflection. The results indicated that the HBT molecule could be an excellent candidate for high-speed and high-sensitive optical switching devices.

Sub-nanosecond optical switch based on silicon racetrack resonator

We experimentally demonstrate a small-size and high-speed silicon optical switch based on the free carrier plasma dispersion in silicon. Using an embedded racetrack resonator with a quality factor of 7400, the optical switch shows an extinction ratio exceeding 13 dB with a footprint of only 2.2 × 10-3 mm^2. Moreover, a novel pre-emphasis technique is introduced to improve the optical response performance and the rise and the fall times are reduced down to 0.24 ns and 0.42 ns respectively, which are 25% and 44% lower than those without the pre-emphasis.

Investigation of the influence of key parameters on system performance in all-optical label switching based on FSK/ASK orthogonal modulation format

The transmission characteristics of the optical label switching system based on the FSK/ASK orthogonal modulation format is investigated. The factors that affect the transmission performance, such as the FSK tone space, dispersion compensation and coupler split ratio, are studied by numerical simulation. The proposed scheme is also experimentally demonstrated with a transmission of 155 Mbit/s FSK label combined with 10 Gbit/s ASK payload.

Observation of V-type electromagnetically induced transparency and optical switch in cold Cs atoms by using nanofiber optical lattice

Optical nanofiber(ONF)is a special tool to achieve the interaction between light and matter with ultralow power.In this paper,we demonstrate V-type electromagnetically induced transparency(EIT)in cold atoms trapped by an ONFbased two-color optical lattice.At an optical depth of 7.35,90%transmission can be achieved by only 7.7 pW coupling power.The EIT peak and linewidth are investigated as a function of the coupling optical power.By modulating the pWlevel control beam of the ONF-EIT system in sequence,we further achieve efficient and high contrast control of the probe transmission,as well as its potential application in the field of quantum communication and quantum information science by using one-dimensional atomic chains.

Research and Progress of Service Driven Optical Switching Network in China

National R&D activities on optical switching networkare introduced. Optical switching network testbedswere established in China including 3T-net andOBS ring and mesh network test-bed with the supportof national '863' program. As an importantmodule in OPS network, a novel all-optical serialmulticast mode is discussed.

Design and Simulation of Routing-switching Protocol Based on Optical Switch Array

An optical routing-switching technology based on optical switch array is proposed.The characteristics of the blocking and nonblocking networks are analyzed and compared,odd-even sorting network is used to realize optical routing-switching,relative routing-switching protocol is designed.Simulation test under load shows that it can reduce a blocking effectively and enhance an efficiency of switching.Further,it can transfer the processing and switching within parallel computer from electric domain to optical domain. It can make parallel computer coordinating computing and processing at much more higher speed, storing and transmitting even more efficiently.

Analysis of electro-optic switches with series-coupled multiple microring resonators

In terms of the coupled mode theory, microring resonance and electro-optic modulation princeple, a reasonable project is proposed for designing an electro-optic switch with the series-coupled multiple microring resonators. The simulation and optimization are performed at the resonant wavelength of 1550 nm. The results are as follows: the core size of the microring is 1.6 μm×1.6 μm, the confined layer between the core and the electrode is 1.6 μm, the thickness of the electrode is 0.15 μm, the radius of the m...

Performance analysis of optical burst switching node with limited wavelength conversion capabilities

The systematical and scalable frameworks were provided for estimating the blocking probabilities under asynchronous traffic in optical burst switching(OBS) nodes with limited wavelength conversion capability(LWCC) . The relevant system architectures of limited range and limited number of wavelength converters(WCs) deployed by a share-per-fiber(SPF) mode were developed,and the novel theoretical analysis of node blocking probability was derived by combining the calculation of discouraged arrival rate in a birth-death process and two-dimensional Markov chain model of SPF. The simulation results on single node performance verify the accuracy and effectiveness of the analysis models. Under most scenarios,it is difficult to distinguish the plots generated by the analysis and simulation. As the conversion degree increases,the accuracy of the analysis model worsens slightly. However,the utmost error on burst loss probability is far less than one order of magnitude and hence,still allows for an accurate estimate. Some results are of actual significance to the construction of next-generation commercial OBS backbones.

Enhancement of modulation depth of an all-optical switch using an azo dye-ethyl red film

The polymethyl methacrylate （PMMA） film doped with an azo dye ethyl-red （ER） film is employed to demonstrate the properties of an all-optical switch by its photoinduced dichroism and birefringence. We show how to enhance remarkably the modulation depth of all-optical switches almost to 100% by using two linear polarization beams： one beam is inclined at 45° with respect to the probing beam and serves as a pumping beam, and the other beam is perpendicular to the probing beam and used as an erasing beam. Furthermore, a maximum-to-minimum output intensity ratio of 2000：1 is achieved in experiment, which is very useful and important for optical storages and image displays.