Wavelength Division Switching Research Articles

Optical path technologies: a comparison among different cross-connect architectures

The introduction of optical technology in the path layer of the transport network is expected to allow scalable and modular networks to be realized. In this paper, different optical cross-connect architectures, based either on space division or wavelength division switching, are analyzed. A comparative investigation is accomplished considering three issues of primary importance: cross-connect modularity, complexity, and transmission performance. In particular, the transmission performance of a generic path through the network is evaluated by upgrading a previously published analytical model, so to more accurately take into account the in-band crosstalk arising in the cross-connect.

A novel all-optical self-routed wavelength-addressable network (SWANET)

A novel all-optical self-routed wavelength-addressable network based on a new multiwavelength routing protocol is proposed. A distributed switching network that uses a low-speed routing header provides a transparent path for the high-speed data while utilizing low-speed electronic processing of the routing header. Each data packet is preceded by a routing header composed of a serial combination of wavelengths. The number of destination addresses is dramatically increased over conventional wavelength-division multiplexing or conventional photonic packet switching networks for the same number of wavelengths or header digits, respectively. A 1/spl times/4 switching node is implemented demonstrating the switching and transmission capabilities of this wavelength-addressable network. >

Applications of optical integrated circuits to signal processing. Semiconductor Optical Functional Devices.

Optical functional devices are indispensable for light signal processing systems. So far, various functions have been realized by use of integrated configuration of semiconductor optical devices, This paper descrides progress in semiconductor optical functonal devices based on semicoductuctor laser diodes and their application to ligh signal processing. First, it is shown that memory operation can be demonstrated with a bistable laser diode with a tandem electrode structure, and then ultra-opical flip-ffop operation of a bistable laser diode is introduced. Second, a wavelength converter laser and a tunable wavelength filter, which are thought to be promising for wavelength division switching networks, ar descrideb. Finally, it is shown that various optical logic operations can be attained by using the bistable laser diode.

A photonic wavelength-division switching system using tunable laser diode filters

A photonic wavelength-division switching system using semiconductor tunable wavelength filters is proposed. A switching system using wavelength switches and multistage switching networks is discussed. A crucial point in developing this switching system is to achieve a large number of wavelength-division channels. The potential of 100 wavelength-division channels in such switching systems is estimated, based on InP optical integrated circuits. A wavelength network synchronization which permits the network to utilize such a large number of wavelength-division channels without wavelength misalignment and drift is proposed. An eight-channel wavelength-division switching experiment, using phase-shift-controlled distributed feedback laser diodes as tunable wavelength filters, is reported. >

A coherent photonic wavelength-division switching system for broad-band networks

A coherent photonic wavelength-division (WD) switching system, utilizing a coherent wavelength switch ( lambda switch), is proposed. In the proposed coherent lambda switch, the tunable wavelength filter function is accomplished using coherent optical detection with a wavelength tunable local oscillator. The coherent photonic WD switching system has the following features; (1) low crosstalk switching for dense WDM signal, and (2) large line capacity capability. Design considerations show that 32 wavelength division channels can be available with a coherent lambda switch. It is also shown that a broadband metropolitan-area-network with over 1000 line capacity is possible, using a multistage connection in the coherent lambda switches. The switching function of the coherent lambda switch is demonstrated in a two-channel wavelength-synchronized switching experiment, using 8-GHz-spaced, 280-Mb/s optical FSK signals.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Semiconductor devices in photonic switching

Three types of photonic switching networks have been proposed, namely, optical space-division switching, optical wavelength-division switching. Optional function devices required for each switching network are as follows: optical switch matrix for space-division switching; optical memory and optical write/read gate for time-division switching; and tunable wavelength filter and wavelength converter for wavelength-division switching. Recent progress in semiconductor functional devices such as modulators, switching devices, bistable devices, and wavelength control devices, which would be key devices to build switching networks, is reviewed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Optical-wavelength switching using distributed-feedback laser diodes

An optical-wavelength converter with tunability greater than 5 AA has been demonstrated using a multielectrode distributed-feedback laser diode (DFB LD) with a saturable absorber. The buried heterostructure GaInAsP/InP LD with first-order grating was fabricated using a MOVPE/LPE (metalorganic vapor-phase epitaxy/liquid-phase epitaxy) hybrid growth method. The p-type electrode was divided into three 100- mu m sections, which can be excited independently through the electrodes. The device emits coherent light only when light input is injected into the saturable absorber, and output wavelength is continuously tuned by the driving currents. This device has high optical gain (input power approximately 330 mu W and output power approximately 1 mW) and can operate at up to 500 MHz. A narrowband optical filter was constructed using the DFB LD amplifier. The DFB LD amplifier selectively amplifies one optical frequency, which can be changed by changing the LD bias current. Extinction ratios greater than 15 dB were obtained for the two optical inputs with a 9.8-GHz frequency difference. The use of the device for optical wavelength-division switching was investigated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>