All-optical Buffer Research Articles

Optical packet switching and buffering by using all-optical signal processing methods

We present a 1 /spl times/ 2 all-optical packet switch. All the processing of the header information is carried out in the optical domain. The optical headers are recognized by employing the two-pulse correlation principle in a semiconductor laser amplifier in loop optical mirror (SLALOM) configuration. The processed header information is stored in an optical flip-flop memory that is based on a symmetric configuration of two coupled lasers. The optical flip-flop memory drives a wavelength routing switch that is based on cross-gain modulation in a semiconductor optical amplifier. We also present an alternative optical packet routing concept that can be used for all-optical buffering of data packets. In this case, an optical threshold function that is based on a asymmetric configuration of two coupled lasers is used to drive a wavelength routing switch. Experimental results are presented for both the 1 /spl times/ 2 optical packet switch and the optical buffer switch.

All-optical picosecond-pulse packet buffer based on four-wave mixing loading and intracavity soliton control

We report an all-optical packet buffer that is based on four-wave mixing loading and intracavity soliton pulse control. The target data packet consisting of picosecond pulses is loaded into the storage-buffer cavity by means of four-wave mixing with the pump pulses and stored at the corresponding idler wavelength. We stabilize the timing and amplitude of the stored idler pulses by applying intracavity all-optical soliton control. This is accomplished by combining the synchronous parametric-gain modulation achieved inside a pulse-pumped nonlinear-optical-loop mirror with the intensity discrimination provided by a nonlinear-amplifying-loop mirror. A 20 Gbit/s-packet pattern is loaded and stored for up to several seconds, corresponding to millions of circulations of the packet within the buffer.

All-optical buffering in all-optical packet switched cross connects

We show that optical packets can be routed in an optical fiber by using an optical threshold function that controls a wavelength converter switch. The optical threshold function is made from two coupled ring lasers. Experimental evidence is given.

Variable semiconductor all-optical buffer

A compact variable all-optical buffer using semiconductor quantum dot structures is proposed. The buffering effect is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic of the medium. The theoretical model shows that a slow-down factor of more than 104 with negligible group velocity dispersion is achievable.

Optical implementation of asynchronous-transfer-mode header-error control

The asynchronous transfer mode (ATM) is a promising technique for broadband switching that is capable of supporting high-bit-rate multimedia services. Progress in all-optical parallel processing shows that photonics may be used in the future in full-functionality ATM switching nodes. All-optical switching fabrics and buffers have already been demonstrated. Fewer studies have been dedicated to ATM header-processing functions. As an example of photonic header processing, the implementation of a header-error control (HEC) subsystem by means of an optical circuit is investigated. Although traditional electronic decoders perform HEC in a serial mode, the architecture chosen for the optical HEC subsystem is based on parallelism, and an appropriate parallel-decoding algorithm was used in designing it.

Parametric gap solitons in quadratic media

Localized energy states such as two-color gap solitons are theoretically and numerically predicted in a periodic structure in the presence of a frequency doubling nonlinearity. These parametric solitons exhibit appealing features as compared to the Kerr case. Novel erects such as merging and all-optical buffering are envisaged.

All-optical buffering of 40-Gb/s data packets

Ultrafast slotted, time-division-multiplexed (TDM) multiaccess networks will utilize optical buffers at user nodes to hold data packets until they are transmitted and to hold received packets until they are demultiplexed or rate converted. We demonstrate the loading and unloading of a compensating optical fiber loop buffer storing packets of 40-Gb/s data for over 300 circulations.

Read/write all-optical buffer by self-trapped gap simultons

Stationary two-colour gap solitons, or simultons, can be excited through nonlinearly induced Bragg localisation in media for second harmonic generation. Such trapped states can be ‘written’ in the structure through the inelastic collision of counterpropagating pulses at the fundamental frequency, and can be ‘read’ and ‘erased’ by launching another pulse of similar characteristics.