Reconfigurable Multi-Passband Optical Filter Using Opto-VLSI Processor

A reconfigurable multi-passband optical filter of 0.5 nm linewidth and a tuning range of 8 nm is demonstrated using an opto-VLSI processor. The wavelength tunability is performed using digital phase holograms uploaded on the opto-VLSI processor

Performance analysis of Gb/s WDM FDDI network

In this paper, we propose a time-token multi-Gb/s Wavelength Division Multiplexing Fibre Distributed Data Interface (WDM/FDDI) architecture and examine its throughput efficiency and delay under heavy load for different network configuration using discrete event simulator

A Tunable Multiwavelength Laser Employing a Semiconductor Optical Amplifier and an Opto-VLSI Processor

We propose and experimentally demonstrate a stable tunable multiwavelength laser employing a semiconductor optical amplifier (SOA) in conjunction with an opto-very-large-scale-integration (VLSI) processor. By uploading digital phase holograms onto the opto-VLSI processor, the amplified spontaneous emission of the SOA is arbitrarily sliced and injected back into the SOA to generate multiple lasing wavelengths with a linewidth of 0.5 nm. Experimental results demonstrate a tunable multiwavelength laser with a tuning range from 1528 to 1533 nm with power fluctuations of less than 0.5 dB

A Novel MicroPhotonic Structure for Optical Header Recognition

In this paper, we propose and demonstrate a new MicroPhotonic structure for optical packet header recognition based on the integration of an optical cavity, optical components and a photoreceiver array. The structure is inherently immune to optical interference thereby routing an optical header within optical cavities to different photo receiver elements to generate the autocorrelation function, and hence the recognition of the header using simple microelectronic circuits. The proof-of-concept of the proposed MicroPhotonic optical header recognition structure is analysed and experimentally demonstrated, and results show excellent agreement between measurements and theory

Opto-VLSI-Based reconfigurable free space optical interconnects architecture

This paper presents a short-distance reconfigurable high-speed optical interconnects architecture employing a Vertical Cavity Surface Emitting Laser (VCSEL) array, Opto-very-large-scale-integrated (Opto-VLSI) processors, and a photodetector (PD) array. The core component of the architecture is the Opto-VLSI processor which can be driven by digital phase steering and multicasting holograms that reconfigure the optical interconnects between the input and output ports. The optical interconnects architecture is experimentally demonstrated at 2.5 Gbps using high-speed 1×3 VCSEL array and 1×3 photoreceiver array in conjunction with two 1×4096 pixel Opto-VLSI processors. The minimisation of the crosstalk between the output ports is achieved by appropriately aligning the VCSEL and PD elements with respect to the Opto-VLSI processors and driving the latter with optimal steering phase holograms

Large area monolithic organic solar cells

Although efficiencies of > 10% have recently been achieved in laboratory-scale organic solar cells, these competitive performance figures are yet to be translated to large active areas and geometries relevant for viable manufacturing. One of the factors hindering scale-up is a lack of knowledge of device physics at the sub-module level, particularly cell architecture, electrode geometry and current collection pathways. A more in depth understanding of how photocurrent and photovoltage extraction can be optimised over large active areas is urgently needed. Another key factor suppressing conversion efficiencies in large area cells is the relatively high sheet resistance of the transparent conducting anode typically indium tin oxide. Hence, to replace ITO with alternative transparent conducting anodes is also a high priority on the pathway to viable module-level organic solar cells. In our paper we will focus on large area devices relevant to sub-module scales - 5 cm x 5 cm monolithic geometry. We have applied a range of experimental techniques to create a more comprehensive understanding of the true device physics that could help make large area, monolithic organic solar cells more viable. By employing this knowledge, a novel transparent anode consisting of molybdenum oxide (MoOx) and silver (Ag) is developed to replace ITO and PEDOT-free large area solar cell sub-modules, acting as both a transparent window and hole-collecting electrode. The proposed architecture and anode materials are well suited to high throughput, low cost all-solution processing

The nature and role of trap states in a dendrimer-based organic field-effect transistor explosive sensor

We report the fabrication and charge transport characterization of carbazole dendrimer-based organic field-effect transistors (OFETs) for the sensing of explosive vapors. After exposure to para-nitrotoluene (pNT) vapor, the OFET channel carrier mobility decreases due to trapping induced by the absorbed pNT. The influence of trap states on transport in devices before and after exposure to pNT vapor has been determined using temperature-dependent measurements of the field-effect mobility. These data clearly show that the absorption of pNT vapor into the dendrimer active layer results in the formation of additional trap states. Such states inhibit charge transport by decreasing the density of conducting states. (C) 2013 AIP Publishing LLC

Design and analysis of high-speed optical correlators for multiwavelength optical header recognition and optical code division multiple access

Optical correlators arc attractive elements for packet-switched optical networks because they enable the headers of high-speed optical packets to be processed and recognised on-the-fly , thus, switching the packets to different destinations without the need for optical-to-electrical and electrical-to-optical conversions. In the first part of the thesis, three novel all-optical header recognition structures based on time-domain optical correlation arc proposed and experimentally demonstrated. The novel optical correlator structures for header recognition, are based on the use of Opto-VLSI processors, fibre Bragg gratings, and arrayed waveguide gratings, respectively, and are demonstrated at IOGb/s by generating auto-correlation functions of high peaks whenever the optical header bit pattern matches a predetermined pattern in the lookup table, while for other bit patterns, only low intensity (below a threshold level) cross-correlation functions are produced. As a result, these structures eliminate the bottleneck that exists in the conventional ortical packet switching networks, thus greatly enhancing the performance of such networks

Throughput and Delay Optimization in WDM FDDI optical Network

The rapidly growing Internet traffic are driving the demands for higher transmission capacity and higher processing speed, especially for the backbone networks. To support such bandwidth usage an optical Fiber Distributed Data Interface Wavelengtg Division Multiplexed (FDDI/WDM) network is proposed, wherein the wavelength channels are amplified using Erbium-Doped Fiber Amplifiers (EDFA\u27s) to compensate for the losses over the optical fiber span. In this paper we investigate the network performance for both asynchronous and synchronous transmissions by measuring the amplified spontaneous emission (ASE) along the ring, the optical signal to noise ratio (OSNR) and the electrical SNR at different destinations. The effects of various network parameters such as synchronous bandwidth allocation and Target Token Ration Time (TTRT) on the network perfomrance are also presented. Results show that when FDDI is used in conjunction with WDM higher throughut and less delay are simutaneously achieved in comparison with FDDI standard networks