Search

Assigning a wavelength label as well as a label in a DPSK modulation format orthogonal to the data payload significantly increases the forwarding and routing capabilities of optical packet routers in IP-over-WDM networks.

Advances in high-speed data transport techniques over polymer optical fibre (POF) networks are reviewed. New approaches such as mode group diversity multiplexing and optical frequency multiplying to carry microwave signals for wireless applications promise even further extension of the POF system capabilities.

A simple and efficient technique to monitor the performance of WDM channels is demonstrated. By combining optical signal processing and electrical adaptive filtering with a maximum data decorrelation criterion, multiple WDM channels can be reconstructed from the composite electrical signals.

An all-optical switching concept for all-optical buffering of packets is presented. The concept feasibility has been verified by showing experimentally that its optical threshold function (>45 dB contrast ratio) can control a wavelength converter switch.

For the first time, InP PHASAR-based wavelength demultiplexers with integrated detectors have been packaged in an industry-standard Butterfly-type module. 8-channel nearly polarisation-independent operation is demonstrated. In addition, 4 nm tuning is realised

A phased-array-based multiwavelength laser has been realized on a chip area of 3.5 x 2.5 mm(2), The device has nine channels, spaced at 400 GHz around a central wavelength of 1.55 mu m. Its performance is characterized by a minimum threshold current of 101 mA, a maximum fiber-coupled power of 0.37 mW, and a linewidth of 21 MHz, In addition, simultaneous four-channel operation is demonstrated

In this paper we present an 8 channel polarisation independent phased array demultiplexer monolithically integrated with photodetectors. The bandwidth of the photodetectors exceeds 10 GHz. On chip losses of the demultiplexer are 3 dB for TE-polarisation. Negligible TE-TM shift was observed

A phased-array-based multiwavelength laser with InGaAsP active layer has been fabricated in a simple ridge waveguide structure with nine channels spaced by 400 GHz around 1.55 mu m on an area of 3.5*3*2.5 mm/sup 2/. Simultaneous dual channel operation is demonstrated

Wavelength division multiplexing (WDM) is an effective technique to exploit the huge bandwidth of optical fibres. Key components in such WDM-systems are demultiplexers which spatially separate the different wavelength channels. Phased-array demultiplexers combine ease of fabrication and low insertion losses. A method is presented for reducing the loss of phased-array wavelength demultiplexers. Feasibility of the concept is demonstrated experimentally for an 8 channel demultiplexer with 2 nm channel spacing employing non-birefringent InGaAsP-on-InP raised strip waveguides. A loss reduction of 1.7 dB for TE polarization and 1.3 dB for TM polarization is demonstrated experimentally

Space switching of 2.5 Gb/s optical signals by lambda -conversion in a DBR laser and subsequent routing through a phased array wavelength demultiplexer is demonstrated. A novel component is presented that integrates 3 dB couplers and a phased array to form the passive part of a space switch

An integrated 4-channel WDM-receiver frontend with 1 GHz channel bandwidth is described. The receiver consists of an integrated wavelength demultiplexer with photodiodes in InP technology connected through bond wires with a 4 channel Si bipolar transimpedance amplifier mounted on an epoxy board. The response is wavelength flattened to within 1.0 nm. The overall crosstalk is at least 25 dB down electrically

The progress in phased array-type (PHASAR) based integrated optical WDM devices like multiplexers, demultiplexers, filters and their use in integrated optical circuits is reviewed. The design rules and their impact on technology in various material systems are discussed. Key parameters like number of channels, channel spacing, insertion loss and polarisation (in-) dependence are addressed

A passive TE/TM mode polarization splitter based on a Mach-Zehnder interferometer is demonstrated. Insertion loss of 1.5 db and extinction ratios of -19 dB for TE and -15 dB for TM have been measured at 1510-nm wavelength. The device attains large optical bandwidth employing a pair of multimode interference (MMI) couplers and a wavelength-tolerant birefringent structure

Design and realization of extremely small InP-based coupling structures with high performance and good compatibility with other components is reported: 3 dB coupler (90 mu m long, 0.7 dB loss), 1*16 coupler (141*32 mu m), Mach-Zehnder interferometer (0.6 dB loss, -28 dB crosstalk)

Experimental results are presented on a new type of planar (Multimode Interference) coupler. Two-mode interference (TMI) couplers (Fig. la) were reported already in 1977 as an alternative to weak synchronous couplers,1 they are shorter and less sensitive to variations in the fabrication process, and thus have a potential for application without trimming or tuning facility. Further, they exhibit less polarization dependence.

The realisation and performance of an all-passive silicon-based 4*4 planar optical hybrid receiver for operation at 1.55- mu m wavelength is reported here for the first time. Measurements show 5 degrees /12 degrees /12 degrees /9 degrees output phase deviations, without tuning or trimming. Network dimensions are 270*1200 mu m. This is the most compact 4*4 planar optical hybrid reported so far, demonstrating the convenience and feasibility of all-passive phase diversity operation

A new type of integrated optical coupler, based on multi-mode interference (MMI) is analysed theoretically and experimentally at 1.52 mu m. Results show high performance: low loss (typically less than 0.5 dB), low polarisation dependence, high reproducibility and small device dimensions