Mingcui Cao

Optical perfect-shuffle-exchange interconnection network using a liquid-crystal spatial light switch.

The perfect-shuffle-exchange interconnection network (e.g., the omega network) is a type of free-space regular multistage interconnection network. An equivalent omega network that consists of left- and right-perfect-shuffle interconnects as well as spatial light switch devices is described. An optical omega network that uses two special polarization prisms and a liquid-crystal spatial light switch is presented. The experimental results of a 8 x 8 omega network are reported. The optical omega network has the features of simple architecture and ease of integration.

Light waveguide electro-optical printed circuit board

The configuration of polymer light waveguide electro-optical printed circuit board(EOPCB) is proposed in this paper. An additional optical layer with light waveguide structure is used in conventional PCB to construct EOPCB. Light waveguide core layer mould is made with SU-8 photolithograph. Polymer light waveguide layer which is embedded between multiplayer PCB is made in experiment by Doctor-blading technology for large size application. Vertical cavity surface emitting laser (VCSEL) array is used as optical transmitter array. PIN photodiode array is used as optical receiver array. A MT-compatible direct coupling method is presented to couple light beam between optical transmitter/receiver with light waveguide layer. The optical signals from a processor element chip on the PCB can transmit to another processor element chip on the same PCB board through light waveguide interconnection in EOPCB. So optical interconnection between chip to chip for parallel multiprocessor system can be reailzed by EOPCB.

A novel routing optical matrix swtiching method

Abstract A routing optical matrix switching method which constitutes of a novel nonblocking routing optical Crossbar network system is presented. The routing optical Crossbar network includes two parts: one is a routing fan-out unit which provides multi-optical channels for each input light beam, and the other is a routing fan-in unit which combines the optical channels with the same destination output port into one. A module of 4×4 routing optical matrix switching module was developed by this method, which is as well applicable to 2×2,8×8, etc. These optical matrix switches can widely be used in the field of DWDM communications.

Optical interconnecting and switching network system of 5- to 10-Gbps bandwidth for parallel computing

A 5 to 10 Gbps bandwidth optical interconnecting and switching network system used on parallel computing is introduced in this paper. This system provides a high bandwidth to meet the request of high bandwidth of the parallel computing. Optics is used to be a media to carry data and optical crossbar interconnection board is used to switch data in this system. It comes over the inherent disadvantage of the R, L, C delay and clock skew of the electronics interconnection. This system has good stability and scalability.

Photonic switching network for parallel multiprocessor cluster system using VCSEL laser arrays

A photonic switching network for parallel multiprocessor cluster system using vertical cavity surface emitting laser (VCSEL) arrays is described. The parallel multiprocessor cluster system provides 64 server nodes interconnected by optical interconnection network with parallel optical links. There are 8 cluster subsystems in the system. Each subsystem includes 8 computers and an optical interconnect backplane of 8x8 crossbar optical interconnection network with VCSEL-based optoelectronic I/O interface. An optical data transmission rate between computers is 5Gb/s which is transmifted by the optical fiber ribbon-based parallel optical data links with 2 channels at data rate of 2.5Gb/s per channel. Every I/O interface between optical interconnection network with each computer includes 16 VCSEL emitter pixels, 16 PIN receiver pixels. VCSEL emitter pixels transformed electrical signals from PCI bus of computer into optical signals, where PIN receiver pixels transformed optical signals from optical interconnect network backplane into electrical signals. The whole optical interconnection network is composed of two level optical interconnect backplanes. A total of 64 computers propagating for data communication of 8 subsystems would be realized.

Free-space regular optical interconnections: a mathematical analysis

The matrix descriptions for three types of free-space regular optical interconnection networks, the perfect shuffle, the banyan, and the crossover, are given. Some new properties of the perfect shuffle are presented in matrix equations, and the equivalence of the three types of interconnection networks is simply shown.

3D optical interconnect mesh network for on-board parallel multiprocessor system based on EOPCB

A three-dimensional (3-D) 4×4×4 optical interconnect Mesh network scheme for parallel multiprocessor system based on polymer light waveguide electro-optical printed circuit board(EOPCB) is proposed in this paper. The Mesh topological structures of light waveguide interconnects for processor element chip-to-chip on a board, and board-toboard on backplane is constructed. The system consists of 64 processor element chips interconnected in a 3-D Mesh network configuration. Every processor board comprises 4x4 processor element chips with Mesh interconnection. Board-to-board Mesh interconnects are established on a backplane through light waveguide Mesh interconnect topological structure. An additional optical layer with light waveguide structure is used in conventional PCB to construct EOPCB. Vertical cavity surface emitting laser (VCSEL) array is used as optical transmitter array. PIN photodiode array is used as optical receiver array. A MT-compatible direct coupling method is presented to couple light beam between optical transmitter/receiver with light waveguide layer. The optical signals from a processor element chip on a board can transmit to another processor element chip on another board through light waveguide interconnection in the backplane. So 3-D optical interconnection Mesh network for parallel multiprocessor system can be reailzed by EOPCB.

4x4 free-space polarization-independent optical switch using half-wave plates for polarized controlling

This paper proposes a novel 4×4 free-space bi-directional fiber optical switch. The switch is independent of the optical polarization, which can lead to polarization-dependent loss. When the input light beam incident on the polarization beam splitters (PBS) coating satisfies Brewster Condition, it is decomposed into two orthogonal linear polarized lights: P-polarized light and S-polarized light. In the paper, the free-space optical switches elements include a polarization control unit and a routing unit, and the former will be discussed emphatically. The polarization control unit can be acted by Ferroelectric Liquid Crystal (FLC) or half-wave plate array. By comparing the two methods, half-wave plate array will be chosen in the experiment. The controlling circuit of driving half-wave plate array is designed and polarization-dependent loss (PDL) in 4×4 optical switch using half-wave plate array is analyzed. The experiment results indicate that the insertion loss is less than 4.4 dB, the interchannel crosstalk is about 32 dB and the switching time of the optical switch is about 2 ms.

Improved optical switching network configuration based on optical interconnection

This paper reported an improved optical switching network configuration based on optical interconnection technology with vertical cavity surface emitting laser (VCSEL) array. The optical switching network consists of two-level optical interconnection backplane. It can connect 64 nodes with parallel optical links. The first level of optical interconnection backplane includes eight 8×8 crossbar interconnect sub-networks. Instead of one 8×8 crossbar interconnect sub-network in the second level of the optical interconnection backplane adopted in our original configuration, the second level of optical interconnection backplane has two 8×8 Crossbar interconnect sub-networks in this improved configuration. So the blocking rate is decreased. VCSEL-based parallel optoelectronic I/O interface is used as O/E conversion. Every I/O parallel interface between optical interconnection network and every node includes 18 VCSEL emitter pixels, 18 PIN receiver pixels. In order to couple 18 signal light beam array into optical fiber array ribbon, a fabrication technique based on the high precise position slot is used for assembling optical fiber array interface. A configuration of coupling packaging for the VCSEL pixel array to the fiber array with 45° end surface is also presented in this paper. An optical data transmission rate between interconnection nodes is 5Gb/s which is transmitted by the optical fiber ribbon-based parallel optical data links with 2 channels at data rate of 2.5Gb/s per channel. The aggregate bandwidth of 360Gbps for an 8×8 Crossbar optical fiber interconnect network backplane is achieved. The reliability of the fiber array with 45° end surface is tested in our experiment.

Photonic switching network with VCSEL array packaging for parallel multiprocessor cluster system

A novel photonic switching network with vertical cavity surface emitting laser (VCSEL) array packaging for parallel multiprocessor cluster system is described. The parallel multiprocessor cluster system provides 64 serve nodes connected by photonic switching network with parallel optical links. There are eight cluster subsystems in the system. Each subsystem includes eight computing nodes and an optical interconnect backplane of 8x8 crossbar optical interconnection network with VCSEL-based optoelectronic I/O parallel interface. Every I/O parallel interface between optical interconnection network and every computing node includes 16 VCSEL emitter pixels, 16 PIN receiver pixels. In order to couple 16 signal light beam array into optical fiber array ribbon, a fabrication technique based on the high precise position slot is used for assembling optical fiber array interface. A packaging structure for optical fiber array interface is presented. As the position slots of optical fiber array interface are formed by VLSI photolithography and IcP etch techniques, and etching depth is smaller compared with V-groove slot, the high precision slots with 25Ojtm pitch can be obtained. A configuration of coupling packaging for 16 VCSEL pixel array to 16 fiber array with 45° end surface is also presented in this paper.