Gf Roberts

Integrated optical 2 /spl times/ 2 switch for wavelength multiplexed interconnects

A highly compact integrated optical switch is proposed and demonstrated for broadband optical switching applications. Routing of 8 /spl times/ 10 Gb/s data channels is demonstrated using a low-cost 1250-Mb/s control scheme. The advantages of lossless operation, broad optical bandwidth, and nanosecond switching times are leveraged. Multichannel wavelength is exploited for reduced latency, enhanced capacity, and functionality, while retaining compatibility with existing off-the-shelf electronics and transceiver technology. The requirements for optical header processing, wavelength translation, and optical buffering are avoided. Low-penalty multiwavelength transmission is demonstrated for a highly compact sub-mm/sup 2/ amplifying 2 /spl times/ 2 switch. Pattern dependent gain and amplified spontaneous emission are minimized to facilitate 0.0-0.4 dB penalty. Mitigation techniques compatible with the architecture are deployed to reduce the penalty under adverse operating conditions. Control schemes are proposed and demonstrated to facilitate 8 /spl times/ 10 Gb/s optically switched networking.

Optical Local Area Networking Using CWDM

This paper describes the current status of Coarse Wavelength Division Multiplexing (CWDM), and then progresses to discuss how it may evolve in networking applications in the future. As WDM can enhance not only transmission but also networking systems, the paper reports a potentially low cost WDM based access node architecture, particularly suited for routing optical data packets on nanosecond timescales. The scheme is cascadable and involves the use of a simple semiconductor optical amplifier (SAO) based add-drop switch. Preliminary results concerning the operation of the add-drop switches under multi-wavelength operation are reported.

Multi-wavelength data encoding for improved input power dynamic range in semiconductor optical amplifier switches

We propose a novel wavelength coding scheme suitable to wavelength striped interconnects and use modelling results to show an improvement in input power dynamic range of an SOA based switch.

Monolithic integration of semiconductor optical switches for optical interconnects

Switches with nanosecond transition times and broad optical bandwidth are investigated for high-capacity low-latency switched optical interconnection. Wavelength multiplexing is exploited for both reduced latency, enhanced capacity and functionality, while using off-the-shelf transceiver technology. The requirement for optical header processing, wavelength translation, and optical buffering is avoided. The design, fabrication and assessment of compact integrated add-drop multiplexers are proposed and demonstrated for application in low-cost wavelength multiplexed and switched optical interconnects. A low-power sub-mm amplifying 2/spl times/2 switched is characterised by four wavelength channel low penalty transmission. Control schemes are proposed and demonstrated to facilitate 80 Gb/s optically switched networking.

Multiwavelength optical add-drop multiplexer with nanosecond reconfiguration times for local area networking

It is desirable for data networks to have low transmission latency. This may be achieved by exploiting the short packet lengths and the high bandwidths that can be achieved using multi-wavelength operation. Semiconductor optical amplifiers (SOAs) have been demonstrated as building blocks for optical switches and have also been shown to be well suited to the fast switching required for optical packet switching [1]. We have realised an InP based add-drop multiplexer (ADM) integrated on a single 850 μm x 850 μm chip. The bit error penalty performance has previously been shown to be below 1.2 dB for each of the operating paths through the device: add, drop and through modes at 2.5 Gbit/s data rates. Further, low penalty operation has previously been demonstrated experimentally with 4 simultaneous wavelengths [2]. It is known that the dynamic range of an SOA can limit the number of wavelengths supported and that the pattern sensitivity in SOAs increases their operating penalty [3]. We investigate the multi-wavelength operation of our ADM device and show that a power penalty of less than 0.8 dB is maintained over a 20 dB input power dynamic range. We also show a -3 dB optical bandwidth of 30 nm suitable for multi-wavelength operation of cascaded ADMs. Finally we present experimental results to show that the pattern dependent operating penalty of the ADM is reduced as the number of wavelengths of asynchronous data is increased. This result may be exploited in our proposed optical data network to produce an improved optical penalty.