An architecture and implementation issues for an almost-all-optical packet switch that does not rely on recirculating loops for storage implementation are presented. The architecture is based on two rearrangeably nonblocking stages interconnected by optical delay lines with different amounts of delay. The probability of loss and the switch latency as a function of link utilization and of the size of the switch are investigated. In general, with proper setting of the number of delay lines, the switch can achieve an arbitrarily low probability of loss. Growability patterns and extension of the design to the dense wavelength-division-multiplexing (WDM) case are also shown. In particular, an extension to the architecture whereby, through the use of WDM, the switch capability can be increased several times, with only minor changes to the switch design is discussed. Additionally, issues involving practical implementation of such a switch are considered. For example, a scheme that allows optical packet synchronization for the synchronously-operated switch is shown. Using this scheme, the switch can be a central component in the design of future all-optical, packet-switched networks. >

The 'staggering switch': an electronically controlled optical packet switch

Recent progress in lithium niobate based integrated optics is reviewed, emphasizing applications in the telecommunications area. Prospects for systems applications are discussed. >

Integrated optics in LiNbO/sub 3/: recent developments in devices for telecommunications

Photonic technologies are reviewed that could become important components of future telecommunication systems. Photonic devices and systems are divided into two classes according to the function they perform. The first class, relational, refers to devices, that map the input channels to the output channels under external control. The second class, logic, perform some type or combination of Boolean logic functions. Some of the strengths and weaknesses of operating in the photonic domain are presented. Relational devices and their applications are discussed. Optical logic devices and their potential applications are reviewed. >

Architectural considerations for photonic switching networks

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The strengths and limitations of the photonic technology are reviewed, beginning with the temporal bandwidth limitations of photonic devices and then focusing on spatial bandwidth, commonly referred to as the parallelism of optics, and how it can be used in photonic fabrics. Some of the proposed photonic switching fabrics that are based on guided-wave devices are discussed, comprising switching fabrics based on space channels, using directional couplers and optical amplifiers, and those based on time channels. The latter include active reconfigurable fabrics based on TDM, time-slot interchangers, and universal time slots, in addition to passive shared media fabrics. Some of the switching fabrics that have been proposed using wavelength channels are outlined, and multidimensional fabrics are briefly reviewed. Photonic switching fabrics based on free-space devices are described, covering free-space relational switching fabrics, the basic hardware required for digital free-space optical fabrics, and digital free-space switching fabrics. >

Photonic switching fabrics

We report on a strictly nonlocking 8×8 integrated optics switch matrix in Ti: LiNbO3. The matrix comprises 64 directional couplers on one chip. Insertion losses less than 7 dB have been measured. The extinction ratio has an average value of 30.5 dB for the directional couplers.

Strictly nonblocking 8×8 integrated optical switch matrix

We report on the first 4 × 4 switch matrix with digital optical switches as switch elements. The matrix is arranged in a tree structure, and comprises 24 switch elements and is pigtailed and packaged.

Integrated optics 4*4 switch matrix with digital optical switches

We report on the performance of a 4×4 polarisation independent LiNbO3switch matrix with a ‘tree-structure’, permitting strictly nonblocking communicative as well as distributive switching

K. Bergvall

Papers

Strictly nonblocking 8×8 integrated optical switch matrix

Integrated optics 4*4 switch matrix with digital optical switches

Tree-structured polarisation independent 4×4 switch matrix in LiNbO3