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- Five channel WDM communication using a single a:SiC-H double pin photo devicePublication . Vaz da Silva, V; Barata, Manuel; Louro, Paula; Vieira, Manuel; Vieira, ManuelaAmorphous SiC heterostructures built as a double pin device has a non linear spectral gain which is a function of the signal wavelength that impinges on its front or back surface. Illuminating the device with several single wavelength data channels in the visible spectrum allows for Wavelength Division Multiplexing (WDM) digital communication. Using fixed ultra-violet illumination at the front or back surfaces enables the recovery of the multiplexed channels. Five channels, each using a single wavelength which is modulated by a Manchester coded signal at 12,000 bps, form a frame with 1024 bits with a preamble for signal intensity and synchronisation purposes. Results show that the clustering of the received signal enables the successful recovery of the five channel data using the front and back illumination of the surfaces of the double pin photo device. (C) 2015 Elsevier B.V. All rights reserved.
- Majority logical function using a pi'npin a-SiC:H structurePublication . Silva, V.; Barata, Manuel; Louro, Paula; Vieira, Manuel; Vieira, ManuelaThe majority logic function has a true output value whenever more than half of the inputs have a true value. Majority logic, also known as majority voting, is used in many systems, for fault-tolerant design, in bioelectronics, and quantum dot cellular automata. The pi'npin heterostructure p-i'(a-SiC:H)-n/p-i(a-Si:H)-n can be illuminated from both back and front surfaces. Steady state illumination, optical bias, controls the light-to-dark sensitivity in the visible range. Several input data channels, each with a different wavelength, illuminate the front surface. Results show that a majority function of 3 and 5 inputs (MAJ-3, MAJ-5) is built with the pi'npin device projecting the way for a MAJ-n function.
- Reconfigurable photonic logic architecture: an overviewPublication . Vaz da Silva, V; Barata, Manuel; Vieira, ManuelaThe photosensor studied in this document, is an amorphous silicon structure deposited on transparent glass allowing illumination on both sides. It responds to wavelengths from near infrared range to the ultra-violet. The front illumination surface is used for inputting light signal. The dynamic characteristics of the photosensor are altered by using optical bias on either surface of the sensor, thus the same input results in different outputs. Experimental studies made with the photosensor evaluate its applicability as a multiplexer, demultiplexer and logical operations device. A memory effect was observed. A programmable pattern emission system, and a validation and recovery system were built to illuminate the sensor with input light signals and to analyze the resulting output.