Optical switch matrix with simplified nxn tree-structure

Large-scale optical switching matrix is the core technology of automatically switched optical network. With the significant increase of the matrix size, the study showed that the nonlinear factors, such as the correlation of the wavelength, phase and polarization between the optical switches have major impacts for the system performance. Because the full-size optical simulation is not available now, the research will be a great significance that we establish an overall model with not only considering the performance of optical switch unit, but also reflecting the structural characteristics of the network.In this paper, we calculated the transmission field of 2×2 Mach –Zehnder(MZI) silica on silicon thermo optic(TO) switch with different structure by using the finite difference beam propagation method(BPM). On the basis of optimization design, we constructed and simulated the large-scale 16×16 MZI silicon-based SiO2 Silica on silicon thermo switching matrix. The results are: In TE Mode, for Crossbar and banyan structures, insertion losses are 13.35 dB and 4.3638 dB; crosstalk losses are 27.125~29.0173 dB and 42.2318-43.7159 dB; extinction ratios are 29.57 dB and 26.79 dB respectively.

Packet-switching characteristics are optimized across an integrated 4 x 4 optical cross-point switch matrix based on active vertical coupler switch cells. Optical gain is demonstrated across the entire matrix with a <3-dB difference between the shortest and longest switching paths.

This paper investigates a novel optical multicast scheme without excess optical splitting loss to be realized using an active vertical coupler (AVC)-based optical switch matrix, due to the optical gain available in the AVC switch cells. Theoretical analysis and computer simulation have been carried out regarding the operational principle and switching characteristics of this scheme. Computer simulation further suggests that the amplified spontaneous emission (ASE)-limited scalability of the scheme can be as high as more than 40. Experiments using an existing 4 /spl times/ 4 switch-matrix device successfully demonstrated the predicted multicast switching operation. Measured switching characteristics and the optical signal-to-noise ratio (OSNR) values are in good agreement with simulation predictions. High switched-signal Q-factor values of 1-to-2 and 1-to-3 multicasting configurations indicate that the scale of the multicasting scheme can be further increased significantly.

A novel optical serial multicast mode scheme using an active vertical coupler optical crosspoint switch matrix has been successfully demonstrated. A fibre delay line has been employed to recirculate optical packets, providing one serial output packet for each recirculation. A minimum Q-factor of 5.68 dB and an optical signal-to-noise-ratio penalty of &lt;2.3 dB are found after nine recirculations.

A folding rearrangeable nonblocking 4×4 optical matrix switch was designed and fabricated on silicon-on-insulator wafer. To compress chip size, switch elements (SEs) were interconnected by total internal reflection (TIR) mirrors instead of conventional S-bends. For obtaining smooth interfaces, potassium hydroxide anisotropic chemical etching of silicon was utilized to make the matrix switch for the first time. The device has a compact size of 20×1.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a fast response of 7.5 μs. The power consumption of each 2×2 SE and the average excess loss per mirror were 145 mW and -1.1 dB, respectively. Low path dependence of /spl plusmn/0.7 dB in total excess loss was obtained because of the symmetry of propagation paths in this novel matrix switch.

SOI (Silicon on Insulator) based photonic devices has attracted more and more attention in the recent years. Integration of SOI optical switch matrix with isolating grooves, total internal reflection (TIR) mirrors and spot size converter (SSC) was studied. A folding re-arrangeable non-blocking 4times4 optical switch matrix and a blocking 16times16 matrix with TIR mirrors and SSC were fabricated on SOI wafer. The performances, including extinction ratio and the crosstalk, are better than before. The insertion loss and the polarization dependent loss (PDL) at 1.55mum increase slightly with longer device length, more bend and intersecting waveguides. The insertion losses decrease 2-3 dB when anti-reflection films are added in the ends of the devices. The rise and fall times of the devices are 2.1mus and 2.3mus, respectively

A low-loss and high-repeatability 4 × 4 optical matrix switch fabricated by using rhombic glass-block switch elements is described. The maximum loss was 1.3 dB and the crosstalk was less than −55 dB, with a switching delay of less than 18 ms.

We successfully reduced the chip size of a 16/spl times/16 optical matrix switch with silica-based planar lightwave circuit technology to 36 %, and the power consumption to 37 % by employing 1.5 % /spl Delta/ waveguides, heat insulating grooves, and a new circuit layout.

Construction of large scale switch matrix by interconnecting integrated optical switch chips with EDFAs

We propose a novel structure that reduces the switching power of a silica-based thermooptic switch (TOSW). The structure consists of silicon trenches and heat insulating grooves, which are formed beneath and beside the arms of a Mach-Zehnder interferometer, respectively. We optimize the structure using the differential-element method (DEM) and fabricate a 2 /spl times/ 2 TOSW with a switching power of only 90 mW, namely, 75% less than that of a conventional TOSW. We also obtain an insertion loss of about 1 dB and an extinction ratio of over 30 dB with a response time from 0% to 90% of 4.9 ms. We then use the structure to fabricate an 8 /spl times/ 8 matrix switch and confirm a total power consumption of 1.4 W with an average insertion loss of 7.4 dB and an extinction ratio of 50.4 dB for 64 possible optical paths.

Monolithically Integrated Optical Gate 2X2 Matrix Switch Using GaAs/AlGaAs Multiple Quantum Well Structure

We present for the first time to our knowledge a comprehensive investigation of linear optical cross talk in an integrated switch-a packaged 4 X 4 semiconductor optical amplifier (SOA) gate switch matrix in InGaAsP-InP and show that the cross talk is a combination of interferometric and noninterferometric effects occuring on the chip.

An InP/InGaAsP optical space switch matrix with 5 polarization-insensitive Mach-Zehnder interferometers in 3 stages and with 6 inputs and 6 outputs for access network applications is reported. The switches, specially designed for a low polarization dependence and low insertion losses, typically show on-state polarization-sensitivities of less than 0.5 dB, nearly identical switching voltages of around 7 V for TE and TM polarization, insertion losses below 11 dB, on-off ratios above 15 dB and high-speed switching capabilities up to 3 Gb/s.

For the first time, the realization and the performance of a compact optoelectronic 32-SOA module including their drivers is reported. Preliminary experiments in an optical packet switching matrix for IP multi-terabit router is also reported.

An optical matrix switch with low- insertion-loss, a flat package and flexible configuration of 18 input/output ports was developed. An array of two-axis electrostatic movable mirrors fabricated by MEMS technology was used to switch optical paths. The mean of measured insertion losses of all 64 paths in an 8×8 switch configuration was 1.1 dB; thus low insertion loss of the switch was confirmed. Loss increase caused by tilt angle drift of the mirrors was reduced to 1.1 dB by applying bias voltage.