M. Zirngibl

LARnet, a local access router network

A novel local access network, LARNet, is proposed and demonstrated. A multifrequency laser, whose wavelength COMB94 is matched to that of a passive waveguide router in the remote node, is used as a downstream signal source. A 1.3-/spl mu/m commercially available LED provides the upstream signal. LARNet solves a major problem of WDM networks, the spectral alignment between the optical wavelengths of different channels. Furthermore. The expensive components are shared among all subscribers. Our measurements indicate that aggregate rates of 2 Gbps downstream and 155 Mbps upstream are feasible.<<ETX>>

A 16*1 wavelength division multiplexer with integrated distributed Bragg reflector lasers and electroabsorption modulators

The integrated operation of a 16*1 wavelength-division-multiplexed (WDM) source with distributed Bragg reflector (DBR) lasers and electroabsorption modulators has been demonstrated. By using repeated holographic exposures and wet chemical etching, 16 different wavelengths from 1.544 to 1.553 mu m with an average channel spacing of 6 AA are obtained. A high-performance combiner is used to obtain a very uniform coupling into the single-output waveguide, and with the integration of an optical amplifier an average optical power of -8 dBm per channel is coupled into a single-mode fiber.<<ETX>>

Optical switch fabrics for ultra-high-capacity IP routers

Next-generation switches and routers may rely on optical switch fabrics to overcome scalability problems that arise in sizing traditional electrical backplanes into the terabit regime. In this paper, we present and discuss several optical switch fabric technologies. We describe a promising approach based on arrayed waveguide gratings and fast wavelength tuning and explain the challenges with respect to technical and commercial viability. Finally, we demonstrate an optical switch fabric capable of 1.2-Tb/s throughput and show packet switching with four ports running at 40 Gb/s each.

Demonstration of a 15*15 arrayed waveguide multiplexer on InP

By interconnecting two star couplers with a waveguide grating, the authors built a monolithic 15*15 multiplexer on InP. The grating order of 148 gives a free spectral range of 10.5 nm (1.3 THz) and a channel spacing of 0.7 nm (87 GHz) at 1550 nm wavelength. A crosstalk between adjacent channels of less than 18 dB and a residual crosstalk of less than 25 dB were obtained. The on-chip insertion loss is typically 2-4 dB.<<ETX>>

An 18-channel multifrequency laser

A multifrequency laser (MFL) is demonstrated that runs simultaneously CW on 18 channels spaced by 103 GHz. The laser emits -14.6-dBm power per wavelength channel into single-mode fiber. Each wavelength channel can be modulated at 1.24 Gb/s. The MFL exhibits a stable and reproducible optical channel spacing owing to the reproducibility of the waveguide grating router that serves as the intracavity filter element.

Digitally tunable channel dropping filter/equalizer based on waveguide grating router and optical amplifier integration

We demonstrate a novel and powerful device that permits individual and simultaneous control of all the wavelength channels in a WDM system. The device is based on the monolithic integration of two identical waveguide grating routers with semiconductor optical amplifiers. By biasing appropriately the individual amplifier, each WDM channel can be amplified, detected or modulated. The device exhibits a channel bandwidth of 60 GHz, a channel spacing of 195 GHz and a crosstalk of /spl minus/19 dB.<<ETX>>

Digitally tunable laser based on the integration of a waveguide grating multiplexer and an optical amplifier

A novel monolithic semiconductor laser is demonstrated. The optical cavity comprises a 1/spl times/N waveguide grating multiplexer connected to N optical amplifiers. By driving a specific output port, laser oscillation is obtained at the wavelength determined by the wavelength path through the multiplexer. Such a laser is very useful for WDM systems because it is capable of producing a comb of precisely spaced frequencies.<<ETX>>

Dynamic gain compensation in saturated erbium-doped fiber amplifiers

Dynamic compensation of low-frequency gain fluctuations in saturated erbium-doped fiber amplifiers is demonstrated. This compensation, based on a simple feedback-loop scheme makes it possible to reduce transient gain fluctuations efficiently across the whole amplifier bandwidth using only a low-power optical feedback signal. Such an, automatic gain control technique could be applied to suppress data packet interference due to traffic bursts in multiple-access networks, as well as in the implementation of long-haul fiber systems using erbium fiber amplifiers.<<ETX>>

An 8-channel digitally tunable transmitter with electroabsorption modulated output by selective-area epitaxy

We demonstrate an 8-frequency digitally tunable laser based on a waveguide grating router with an electroabsorption modulated output. The laser wavelengths range from 1.567 to 1.580 /spl mu/m with channel spacings of 200 GHz (1.6 nm). The modulator extinction is -10 dB/VN with a -5-V bias. A unique output coupler design delivers an ASE noise suppression of -55 dB//spl Aring/.<<ETX>>

Study of spectral slicing for local access applications

We demonstrate a spectrally sliced wavelength division multiplexed network that employs two waveguide grating routers and commercially available LEDs at 1.3 /spl mu/m. The system runs error free on six channels, each one modulated at 155 Mbps. We also investigate power penalties that may occur from router crosstalk and spectral mismatch between the two routers.