Flexibly reconfigurable fiber-wireless network using wavelength routing techniques: the ACTS project AC349 PRISMA

A dynamically reconfigurable fiber-wireless network using flexible wavelength routing techniques is proposed by the PRISMA project, which offers a "forecast-tolerant" solution for handling a wide variety of wireless services and capacity demands as may emerge in the fast evolving market of mobile communications. This approach can considerably increase the operation efficiency of wireless networks for broadband nomadic services (wireless LANs). It also supports the evolution from GSM and GPRS towards UMTS, and the entry of new operators and/or services into the liberalized mobile communications market. The system has been implemented in a field trial and has been operated successfully with real users and broadband nomadic services. The system concept is ready for further development into products

Integrated optical circuit comprising a polarization convertor

An integrated optical circuit includes a first device and a second device, which devices are connected by a polarization convertor. The polarization convertor includes a curved section of a waveguide, integrated in the optical circuit. The curved section may have several differently curved subsections. The conversion ratio is determined in part by the radius of curvature of the curved subsections as well as by the number of transitions between subsections

Plasma-enhanced chemical vapor deposition of thick silicon nitride films with low stress on InP

We have developed a low-temperature plasma-enhanced chemical vapor deposition process that facilitates the deposition of silicon nitride films with controlled stress by using periodically alternating high- and low-frequency power sources. Very thick films of 3 mu m with low stress were deposited on InP substrates. Suitable sidewall profiles for metallization are obtained at 250 degrees C deposition temperature. A 3- mu m-thick low-stress nitride film was successfully applied to reduce the capacitance of bond pad for an array of four InP based photodetectors, that were integrated with a four channel phased-array wavelength demultiplexer. The capacitance of the detectors was below 0.5 pF at -5 V bia

System performance of a 4-channel PHASAR WDM receiver operating at 1.2 Gbit/s

Phased arrays are important key components in wavelength-division multiplexing (WDM) systems. We have realized a 4-channel WDM receiver combining a phased array with photodetectors on InP with a Si bipolar transimpedance amplifier. The channels are spaced at 2.0 nm with a 1.0-nm flat passband. On chip loss was 6-7 dB and detector efficiency was better than 90%. The optical cross talk remains below -20 dB. The electrical bandwidth per channel was 1 GHz. The electrical cross talk at 1 GHz after detection is below -25 dB. We have tested this receiver in a full 4-channel syste

Plasma-enhanced chemical vapor deposition of thick silicon nitride films with low stress on InP

We have developed a low-temperature plasma-enhanced chemical vapor deposition process that facilitates the deposition of silicon nitride films with controlled stress by using periodically alternating high- and low-frequency power sources. Very thick films of 3 mu m with low stress were deposited on InP substrates. Suitable sidewall profiles for metallization are obtained at 250 degrees C deposition temperature. A 3- mu m-thick low-stress nitride film was successfully applied to reduce the capacitance of bond pad for an array of four InP based photodetectors, that were integrated with a four channel phased-array wavelength demultiplexer. The capacitance of the detectors was below 0.5 pF at -5 V bia

High Capacity Integrated Optical Receivers

Electrical Engineering, Mathematics and Computer Scienc

Flexibly reconfigurable fiber-wireless network using wavelength routing techniques: the ACTS project AC349 PRISMA

A dynamically reconfigurable fiber-wireless network using flexible wavelength routing techniques is proposed by the PRISMA project, which offers a "forecast-tolerant" solution for handling a wide variety of wireless services and capacity demands as may emerge in the fast evolving market of mobile communications. This approach can considerably increase the operation efficiency of wireless networks for broadband nomadic services (wireless LANs). It also supports the evolution from GSM and GPRS towards UMTS, and the entry of new operators and/or services into the liberalized mobile communications market. The system has been implemented in a field trial and has been operated successfully with real users and broadband nomadic services. The system concept is ready for further development into products