Switching to Photonics

The use of hardware that exploits the interplay of photons and electrons to switch voice, data, and video is discussed. The two directions being taken by current research-guided-wave and free-space photonics-are examined. Photonic time-slot interchanges are described. Multidivisional fabrics, based on a combination of space-division and time-division multiplexing, are considered, as is the wavelength-division-based photonic packet switch, another kind of multidimensional fabric. The use of self-electrooptic effect devices, (SEEDs) is discussed

Multiple Quantum-Well Technology Takes SEED

Progress in the development of self-electrooptic-effect devices (SEEDs) is discussed. The devices include the resistor-SEED (R-SEED) device, which can be viewed as a simple NOR gate. The symmetric SEED (S-SEED) and the logic-SEED (L-SEED) devices with improved features, functionality, and performance are also considered. The integration of FETs with multiple quantum well (MQW) modulators (FET-SEED), enables optical interconnections of electronic circuits. Where the SEED technology can be used is discussed, and an experimental optical switching fabric made using these devices is described

Architectural Considerations for Photonic Switching Networks

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

An Optical Backplane Demonstrator System Based on FET-SEED Smart Pixel Arrays and Diffractive Lenslet Arrays

We have demonstrated a representative portion of an optical backplane using FET-SEED smart pixels and free-space optics to interconnect printed circuit boards (PCB\u27s) in a two board, unidirectional link configuration. 4×4 arrays of FET-SEED transceivers were designed, fabricated, and packaged all the PCB level, The optical interconnection was constructed using diffractive microoptics, and custom optomechanics. The system was operated in two modes, one showing high data throughput, 100 MBit/sec, and the other demonstrating large connection densities, 2222 channel/cm2

Photonics in Switching

One of the keys to the future of telecommunications companies will be their ability to provide new broadband services to both the business community and residential customers. With the new services will come the need for the equivalent of a broadband switching office. Such a system could require the capability of supporting in excess of 10000 users with broadband channel bit rates exceeding 100 Mb/s. This implies a switching fabric the aggregate bit rate of which could be greater than 1 Tb/s. Guided-wave technology and free-space technology switching fabrics are discussed. Three time-division-based switching fabrics are proposed, and two wavelength-division-based switching fabrics and two multidivision fabrics are described. The fine-grain space-division fabrics associated with S-SEED devices are discussed. The ways in which 2-D optoelectronic integrated circuits (2D-OEICs) or smart pixels could be used as the building blocks for larger and more complex switching fabrics are described

Photonic Switching TechnologyApplications

This paper will review some of the possible photonics technologies that could become important components of future telecommunications systems. It will begin by dividing photonic devices and systems into two classes according to the function they perform. The first class, relational, is associated with devices that, under external control, map the input channels to the output channels. The second class, logic, requires that the devices perform some type of Boolean logic function. After the classes are defined, some of the strengths and weaknesses of the photonic domain will be presented. Relational devices and their applications will then be discussed with a special focus on the spatial light modulator and the directional coupler. This will be followed by a description of two of the optical logic devices, the self‐electro‐optic device and the nonlinear Fabry‐Perot etalon. Finally, there will be a brief discussion of optical logic systems and their potential applications

Free-SpacePhotonics in Switching

Free-space digital optics is a new technology that exploits the ability of optics to handle thousands of light beams, or information channels, at once. This and other features of optics complement the strengths and weaknesses of purely electronic systems. Especially when combined with electronics, free-space optics allows the development of new architectures in digital systems. In particular, it offers large numbers of closely spaced interconnections inside digital processors that can be used to make large digital switching fabrics. In this paper, we outline some of the strengths and weaknesses of this emerging technology, and we briefly describe some of its experimental systems

Symmetric Self-Electro-Optic Effect Device: Optical Set-Reset Latch, Differential Logic Gate, and Differential Modulator/Detector

The symmetric self-electrooptic-effect device (S-SEED), a structure consisting of two p-i-n diodes electrically connected in series and acting as an optically bistable set-reset latch, is discussed. Applications and extensions of this device are also discussed. The devices do not require the critical biasing that is common to most optically bistable devices and thus is more useful for system applications. They have been optically cascaded in a photonic ring counter and have been used to perform different NOR, OR, NAND, and AND logic functions. Using the same device, a differential modulator that generates a set of complementary output beams with a single voltage control lead and a differential detector that gives an output voltage dependent on the ratio of the two optical input powers have been demonstrated