SiC Multilayer Structures as Light Controlled Photonic Active Filters

Abstract

Tunable wavelength division multiplexing converters based on amorphous SiC multilayer photonic active filters are analyzed. The configuration includes two stacked p-i-n structures (p(a-SiC:H)-i'(aSiC:H)-n(a-SiC:H)-p(a-SiC:H)-i(a-Si:H)-n(a-Si:H)) sandwiched between two transparent contacts. The manipulation of the magnitude is achieved through appropriated front and back backgrounds. Transfer function characteristics are studied both theoretically and experimentally. An algorithm to decode the multiplex signal is established. An optoelectronic model supports the optoelectronic logic architecture. Results show that the light-activated device combines the demultiplexing operation with the simultaneous photodetection and self-amplification of an optical signal. The output waveform presents a nonlinear amplitude-dependent response to the wavelengths of the input channels. Depending on the wavelength of the external background and irradiation side, it acts either as a short-or a long-pass band filter or as a bandstop filter. A two-stage active circuit is presented and gives insight into the physics of the device.

Cooperative guidance system for mobile users inside large buildings based on visible light communication

“…The transmitted data is decoded by comparing the code MUX signal with the parity MUX levels. The decoding algorithm is based on a proximity search [22]. For each time slot, the data are translated into a vector in multidimensional space, which is determined by the signal currents I 1 and I 2 , where I 1 is the d level and I 2 is the p level for the 4-bit codeword (RGBV).…”

VIS/NIR wavelength selector based on a multilayer pi'n/pin a‐SiC:H optical filter

“…Under back irradiation due to the different enhancement of the violet and blue optical gains, if only three channels are present the blue channel is selected otherwise the violet will be tuned. This nonlinearity provides the possibility for selective tuning the different wavelengths allowing their recognition [8,9]. In Fig.…”

“…2c) it is possible to identify them, since under back irradiation the MUX signal receive its main contribution from the 400nm channel, while under front irradiation it is mainly weighed by the long wavelength channels. By comparing front and back irradiation is possible to decode the transmitted information [8]. Taking into account the device configuration (Fig.…”

“…A transmission capability of 30 kbps was achieved. The decoding algorithm is based on a proximity search [8]. Each time slot is translated to a vector in multidimensional space.…”

Switching characteristic and capacitance analysis of a-Si:H pinpin photodiodes for visible range telecommunications

“…This device structure has been shown very versatile and has been referenced in different photonic applications: as an integrated wavelength optical filter and photodetector for Visible Light Communication (VLC) [1], as a visible/near-infrared (VIS/NIR) wavelength selector that requires appropriate nearultraviolet steady states optical switches to select the desired wavelengths [2] and as a five channel WDM communication Multiplexer/Demultiplexer [3]. The application of this device in WDM POF-based communications presents interesting aspects for its simplicity and flexibility of application [4,5].There is indeed evidence that the retrieval of the multiplexed information is based on capacitive effects that are characteristic of this device family, being the intensity of these capacitive effects depending on light intensity and wavelength and on the background illumination conditions and applied electrical bias [6].The behaviour of the device has been explained by a photo-capacitance effect controlled through the accumulation of trapped charge localized in the intrinsic layers [7]. Anyway, its full applicability is limited, in its present state of development, by its response time and low rate of communication flow, in the order of 10 kHz range.…”