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Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.
Alessandro Fantoni; João Costa; Paulo Lourenço; Manuela Vieira. Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality. The European Physical Journal Applied Physics 2020, 90, 30502 .
AMA StyleAlessandro Fantoni, João Costa, Paulo Lourenço, Manuela Vieira. Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality. The European Physical Journal Applied Physics. 2020; 90 (3):30502.
Chicago/Turabian StyleAlessandro Fantoni; João Costa; Paulo Lourenço; Manuela Vieira. 2020. "Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality." The European Physical Journal Applied Physics 90, no. 3: 30502.
This work reports the optimisation of a plasmonic waveguide sensor based on amorphous silicon compounds (a-SiC:H, a-SiN:H or a-SiCN:H) using the FDTD method and modal decomposition. The sensor consists of an array of parallel surface plasmon interferometers with different propagation lengths, each one comprising a thin layer of metal embedded into an amorphous silicon waveguide. In order to reduce the complexity and hardware, we have proposed a structure consisting of an array of parallel surface plasmon interferometers with different propagation lengths, such that at the end of the plasmonic structure the modes can interfere constructively or destructively depending on the refractive index of the sampling medium and the propagation length. The variation of the output intensity at the end of each waveguide element provides a convenient interrogation scheme. In this work we analyse different solutions for splitting the input fundamental mode into the different parallel waveguides, including multi-mode interference structures and directional coupler splitters. By exploring amorphous silicon compounds that can be deposited by Pressure Enhanced Chemical Vapor Deposition (PECVD) at low temperatures, we aim to achieve a low-cost process that is compatible with back-end CMOS processing and wavelengths in the visible to near infrared range.
João Costa; Alessandro Fantoni; Paulo Lourenço; Manuela Vieira. Optimisation of a plasmonic parallel waveguide sensor based on amorphous silicon compounds. Optical Sensing and Detection VI 2020, 11354, 113542K .
AMA StyleJoão Costa, Alessandro Fantoni, Paulo Lourenço, Manuela Vieira. Optimisation of a plasmonic parallel waveguide sensor based on amorphous silicon compounds. Optical Sensing and Detection VI. 2020; 11354 ():113542K.
Chicago/Turabian StyleJoão Costa; Alessandro Fantoni; Paulo Lourenço; Manuela Vieira. 2020. "Optimisation of a plasmonic parallel waveguide sensor based on amorphous silicon compounds." Optical Sensing and Detection VI 11354, no. : 113542K.
Lithographic technology has been one of the main upholders to Moore's law in the semiconductor industry for the last decades. The underlying reason that enabled the evolution in semiconductor industry has been a steady silicon wafer printing cost, while being able to dramatically increase the number of nodes that can be printed per chip. Key developments in lithography such as wavelength decreasing, together with performance increase in lens and imaging technology, should be accounted for almost all the reduction of cost per function in integrated circuits technology. In this work, we will be presenting the simulation of two mitigation techniques for the impact of defects introduced by manufacturing processes. Namely, the lithographic mask limited resolution on the geometry of the representative device. These perturbations are a consequence of the lithographic mask limited resolution on the geometry of the representative device. For this purpose, the Beam Propagation and Finite Differences Time Domain methods will be used to simulate a multimode interference structure based on silicon nitride. The structure will be affected by previously mentioned perturbations and we expect results revealing a strong dependence between mask resolution, and imbalance and power loss. Two strategies will be followed concerning the mitigation of power loss and imbalance introduced by the limited resolution of lithographic mask: - Access waveguides tapering; - Adjustable power splitting ratios through the electro-optic effect. Through both strategies we aim to achieve an improvement on device’s performance but, in the latter are expected finer tuning capabilities, being enabled by dynamic compensation of power loss and imbalance when in a closed loop control architecture.
Paulo Lourenço; Alessandro Fantoni; João Costa; Manuela Vieira. Silicon nitride based devices: lithographic mask roughness mitigation. Integrated Photonics Platforms: Fundamental Research, Manufacturing and Applications 2020, 11364, 113641Q .
AMA StylePaulo Lourenço, Alessandro Fantoni, João Costa, Manuela Vieira. Silicon nitride based devices: lithographic mask roughness mitigation. Integrated Photonics Platforms: Fundamental Research, Manufacturing and Applications. 2020; 11364 ():113641Q.
Chicago/Turabian StylePaulo Lourenço; Alessandro Fantoni; João Costa; Manuela Vieira. 2020. "Silicon nitride based devices: lithographic mask roughness mitigation." Integrated Photonics Platforms: Fundamental Research, Manufacturing and Applications 11364, no. : 113641Q.
Surface Plasmon Resonance occurs when a polarized electromagnetic field strikes a metallic surface at the separation interface between metal and an insulator. This phenomenon is characterized by the conduction electrons resonant oscillation at the interface, resulting on propagating plasmon waves on the metallic surface. Since this wave is generated at the boundary between the metallic surface and the external medium, these structures are highly sensitive to alterations on the surrounding environment, namely the refractive index, and may be used in sensing structures. The large majority of these devices use noble metals, namely gold or silver, as the active material. These metals present low resistivity, which leads to low optical losses in the visible and near infrared spectrum ranges. Gold shows high environmental stability, which is essential for long-term operation, and silver’s lower stability can be overcome through the deposition of an alumina layer. However, their high cost is a limiting factor if the intended target is large scale manufacturing. In this work, we performed Finite Differences Time Domain simulations on a Surface Plasmon Resonance based sensing structure, considering cost-effective materials such as aluminium for the active metal and hydrogenated amorphous silicon for the waveguide supporting elements, and verified that these structures are able to detect refractive index variations of the surrounding environment at the 1550 μm operating wavelength. This sensing architecture has also been modelled with dispersive materials, losses included, to reflect as much as possible physical reality, revealing good performance capabilities when compared to similar noble metals based devices.
Paulo Lourenço; Alessandro Fantoni; Paula Louro; João Costa; Manuela Vieira. Surface plasmon resonance sensing structure. Physics and Simulation of Optoelectronic Devices XXVIII 2020, 11274, 1127415 .
AMA StylePaulo Lourenço, Alessandro Fantoni, Paula Louro, João Costa, Manuela Vieira. Surface plasmon resonance sensing structure. Physics and Simulation of Optoelectronic Devices XXVIII. 2020; 11274 ():1127415.
Chicago/Turabian StylePaulo Lourenço; Alessandro Fantoni; Paula Louro; João Costa; Manuela Vieira. 2020. "Surface plasmon resonance sensing structure." Physics and Simulation of Optoelectronic Devices XXVIII 11274, no. : 1127415.
Surface plasmon resonance sensors have emerged has one of the most suitable approaches for biosensing. A common approach consists of exciting the plasmons at the interface between a functionalized metal film and a sample medium containing the analyte. The propagation of the surface plasmon is highly dependent on changes of the refractive index of the surrounding environment thus providing a mechanism for sensing. The typical interrogation schemes are based on scanning over the wavelength or the incident angle to search for the resonance condition. These solutions require additional motor-driven rotation stages, prisms or other bulky components, introducing complexity which prevents the fabrication of fully on-chip devices. This work reports a simulation study of an amorphous silicon waveguide structure consisting of an array of parallel surface plasmon interferometers with different propagation lengths, each one comprising a thin layer of gold embedded into a-Si:H waveguide. The surface plasmon modes at the end of the plasmonic structure can interfere constructively or destructively depending on the refractive index of the analyte and the interferometer’s length. The variation of the output intensity at the end of each element of the array provides a convenient interrogation scheme that is suitable for on-chip integration. In this paper we investigate this setup and analyze the output power at the end of the array as a function of the refractive index of the sampling medium. The setup is simulated and characterized by the eigenmode expansion method.
João Costa; Alessandro Fantoni; Paulo Lourenço; Manuela Vieira. Simulation of a parallel waveguide array structure suitable for interrogation scheme in a plasmonic biosensor. Physics and Simulation of Optoelectronic Devices XXVIII 2020, 11274, 112742B .
AMA StyleJoão Costa, Alessandro Fantoni, Paulo Lourenço, Manuela Vieira. Simulation of a parallel waveguide array structure suitable for interrogation scheme in a plasmonic biosensor. Physics and Simulation of Optoelectronic Devices XXVIII. 2020; 11274 ():112742B.
Chicago/Turabian StyleJoão Costa; Alessandro Fantoni; Paulo Lourenço; Manuela Vieira. 2020. "Simulation of a parallel waveguide array structure suitable for interrogation scheme in a plasmonic biosensor." Physics and Simulation of Optoelectronic Devices XXVIII 11274, no. : 112742B.
In this paper, we present a simulation study that intends to characterize the influence of defects introduced by manufacturing processes on the geometry of a semiconductor structure suitable to be used as a multimode interference (MMI) 3 dB power splitter. Consequently, these defects will represent refractive index fluctuations which, on their turn, will drastically affect the propagation conditions within the structure. Our simulations were conducted on a software platform that implements the Beam Propagation numerical method. This work supports the development of a biomedical plasmonic sensor, which is based on the coupling between propagating modes in a dielectric waveguide and the surface plasmon mode that is generated on an overlaid metallic thin film, and where the output readout is achieved through an a-Si:H photodiode. By using a multimode interference 1 × 2 power splitter, this sensor device can utilize the non-sensing arm as a reference one, greatly facilitating its calibration and enhancing its performance. As the spectral sensitivity of amorphous silicon is restricted to the visible range, this sensing device should be operating on a wavelength not higher than 700 nm; thus, a-SiNx has been the material hereby proposed for both waveguides and MMI power splitter.
Paulo Lourenço; Alessandro Fantoni; João Costa; Manuela Vieira. Lithographic Mask Defects Analysis on an MMI 3 dB Splitter. Photonics 2019, 6, 118 .
AMA StylePaulo Lourenço, Alessandro Fantoni, João Costa, Manuela Vieira. Lithographic Mask Defects Analysis on an MMI 3 dB Splitter. Photonics. 2019; 6 (4):118.
Chicago/Turabian StylePaulo Lourenço; Alessandro Fantoni; João Costa; Manuela Vieira. 2019. "Lithographic Mask Defects Analysis on an MMI 3 dB Splitter." Photonics 6, no. 4: 118.
In this work we present a simulation study about the characteristics of a semiconductor structure suitable to be used as a guided wave optical biosensor, based on Surface Plasmonic Resonance effects (SPR). The proposed structure is a planar metal-dielectric waveguide where the sensor operation is based on the coupling between the fundamental propagation TM mode and the surface plasmon excited at the outer boundary of the metal, which interfaces the sample medium. Gold and aluminum are the metals considered for the plasmonic coating, amorphous silicon and others PECVD materials are considered for the waveguide structure. The results are based on modal analysis of the waveguide and plasmonic modes. The results obtained point out the possibility of generating SPPs in the near infrared range by including a functionalized cover of reduced graphene oxide (rGO) over the metal layer.
Alessandro Fantoni; João Costa; Miguel Fernandes; Yuri Vygranenko; Manuela Vieira. A simulation analysis for dimensioning of an amorphous silicon planar waveguide structure suitable to be used as a surface plasmon resonance biosensor. Fourth International Conference on Applications of Optics and Photonics 2019, 11207, 112070A .
AMA StyleAlessandro Fantoni, João Costa, Miguel Fernandes, Yuri Vygranenko, Manuela Vieira. A simulation analysis for dimensioning of an amorphous silicon planar waveguide structure suitable to be used as a surface plasmon resonance biosensor. Fourth International Conference on Applications of Optics and Photonics. 2019; 11207 ():112070A.
Chicago/Turabian StyleAlessandro Fantoni; João Costa; Miguel Fernandes; Yuri Vygranenko; Manuela Vieira. 2019. "A simulation analysis for dimensioning of an amorphous silicon planar waveguide structure suitable to be used as a surface plasmon resonance biosensor." Fourth International Conference on Applications of Optics and Photonics 11207, no. : 112070A.
Oxygen saturation levels in blood are usually measured with photoplethysmography (PPG) using two LEDs, one in the red and the other in the near infrared region of the spectrum. A number of studies have increased the number of wavelengths, not only to improve the accuracy of SpO2 measurements, but also to provide real-time measurements of other substances in blood, such as methemoglobin and carboxyhemoglobin. In addition, analysis of PPG signals at different wavelengths could provide information about skin pathologies at various tissue depths. In this work we study the advantages of using photodetection based on vertically stacked double junction photodiodes. The sensitivity of such photodetectors over a wider wavelength range is of particular interest for PPG. We have implemented a test bed, which includes the control of light sources to emulate the transmitted signals, the analog front-end to recover the time multiplexed PPG signals and post-processing to calculate the hemoglobin fractions. We use this framework to compare results of photodetection obtained using a single silicon junction and the combination of a silicon and indium gallium arsenide junction for photodetection.
João Costa; Hugo Vieira; Paula Louro; Manuela Vieira. Double junction photodiodes for multiwavelength photoplethysmography. Optical Sensing and Detection V 2018, 10680, 106802H .
AMA StyleJoão Costa, Hugo Vieira, Paula Louro, Manuela Vieira. Double junction photodiodes for multiwavelength photoplethysmography. Optical Sensing and Detection V. 2018; 10680 ():106802H.
Chicago/Turabian StyleJoão Costa; Hugo Vieira; Paula Louro; Manuela Vieira. 2018. "Double junction photodiodes for multiwavelength photoplethysmography." Optical Sensing and Detection V 10680, no. : 106802H.
In this research we present a system based on Visible Light Communication (VLC) with the dual purpose of indoor positioning and data transmission. We propose a system based on RGB white LEDs and a pinpin phototetector based on a-SiC:H/a-Si:H to detect the optical signals transmitted y the modulated emitters of the LEDs. A unit navigation cell is defined and characterized by a unique identifier, and the concept is enlarged to adjacent cells. Within each cell, each spatial region is assigned by the optical pattern of the correspondent emitters. Besides, the positioning and navigation functionality, additional data transmission is also demonstrated using four different channels in each navigation cell. A specific codification scheme and decoding algorithm are proposed and discussed. Error control methodology is also presented to enhance the decoding process.
Paula Louro; Manuel Augusto Vieira; Manuel Augusto Vieira; João Costa; Fabio Rodrigues. Design of a transmission system for indoors navigation based on VLC. Optical Sensing and Detection V 2018, 10680, 106800I .
AMA StylePaula Louro, Manuel Augusto Vieira, Manuel Augusto Vieira, João Costa, Fabio Rodrigues. Design of a transmission system for indoors navigation based on VLC. Optical Sensing and Detection V. 2018; 10680 ():106800I.
Chicago/Turabian StylePaula Louro; Manuel Augusto Vieira; Manuel Augusto Vieira; João Costa; Fabio Rodrigues. 2018. "Design of a transmission system for indoors navigation based on VLC." Optical Sensing and Detection V 10680, no. : 106800I.
White LEDS revolutionized the field of illumination technology mainly due to the energy saving effects. Besides lighting purposes LEDs can also be used in wireless communication systems when integrated in Visible Light Communication (VLC) systems. Indoor positioning for navigation in large buildings is currently under research to overcome the difficulties associated with the use of GPS in such environments. The motivation for this application is also supported by the possibility of taking advantage of an existing lighting and WiFi infrastructure. In this work it is proposed an indoor navigation system based on the use of VLC technology. The proposed system includes trichromatic white LEDs with the red and blue chips modulated at different frequencies and a pinpin photodetector with selective spectral sensitivity. Optoelectronic features of both optical sources and photodetector device are analyzed. The photodetector device consists two pin structures based on a-SiC:H and a-Si:H with geometrical configuration optimized for the detection of short and large wavelengths in the visible range. Its sensitivity is externally tuned by steady state optical bias. The localization algorithm makes use of the Fourier transform to identify the frequencies present in the photocurrent signal and the wavelength filtering properties of the sensor under front and back optical bias to detect the existing red and blue signals. The viability of the system was demonstrated through the implementation of an automatic algorithm to infer the photodetector cardinal direction. A capacitive optoelectronic model supports the experimental results and explains the device operation.
Paula Louro; M.A. Vieira; João Costa; M.A. Vieira. On-off keying transmitter design for navigation by visible light communication. Optical Interconnects XVIII 2018, 10538, 1053809 .
AMA StylePaula Louro, M.A. Vieira, João Costa, M.A. Vieira. On-off keying transmitter design for navigation by visible light communication. Optical Interconnects XVIII. 2018; 10538 ():1053809.
Chicago/Turabian StylePaula Louro; M.A. Vieira; João Costa; M.A. Vieira. 2018. "On-off keying transmitter design for navigation by visible light communication." Optical Interconnects XVIII 10538, no. : 1053809.
Info:eu-repo/semantics/publishedVersio
Paula Louro; João Costa; Manuela Vieira. Optical communication applications based on white LEDs. Journal of Luminescence 2017, 191, 122 -125.
AMA StylePaula Louro, João Costa, Manuela Vieira. Optical communication applications based on white LEDs. Journal of Luminescence. 2017; 191 ():122-125.
Chicago/Turabian StylePaula Louro; João Costa; Manuela Vieira. 2017. "Optical communication applications based on white LEDs." Journal of Luminescence 191, no. : 122-125.
Paula Louro Antunes; M. A. Vieira; João Costa; M. Vieira. Indoors positioning through VLC technology using an a-SiC:H photodetector. Third International Conference on Applications of Optics and Photonics 2017, 1 .
AMA StylePaula Louro Antunes, M. A. Vieira, João Costa, M. Vieira. Indoors positioning through VLC technology using an a-SiC:H photodetector. Third International Conference on Applications of Optics and Photonics. 2017; ():1.
Chicago/Turabian StylePaula Louro Antunes; M. A. Vieira; João Costa; M. Vieira. 2017. "Indoors positioning through VLC technology using an a-SiC:H photodetector." Third International Conference on Applications of Optics and Photonics , no. : 1.
In this research we present a Visible Light Communication (VLC) system for indoor positioning and navigation. The viability of this methodology was demonstrated in previous work for indoor positioning within the unit navigation cell. In this paper it is proposed to extend this concept for navigation in wider spaces that demand more than one navigation unit. The proposed system uses white RGB LEDs of wide divergence angle and a specific photodetector dedicated to the selective wavelengths detection of red, green and blue light. The photodetector is a multilayered pin-pin heterostructure based on a-SiC:H/a-Si:H, such that the spectral sensitivity can be controlled externally by steady state background light. The RGB emitters of the white LED were modulated with specific bit sequences and frequency to assign different optical excitations to each spatial region. The measurement of the induced photocurrent signal by the detector allows the identification of the position. For this purpose the decoding algorithm for the photocurrent signal processing uses the filtering properties of the photodetector for the recognition of the navigation cell word code, and detection of the wavelength and Fourier analysis for recognition of the signal frequency. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
P. Louro; João Costa; M. Vieira; M. A. Vieira; Y. Vygranenko. Use of VLC for indoors navigation with RGB LEDs and a-SiC:H photodetector. Optical Sensors 2017 2017, 10231, 102310 .
AMA StyleP. Louro, João Costa, M. Vieira, M. A. Vieira, Y. Vygranenko. Use of VLC for indoors navigation with RGB LEDs and a-SiC:H photodetector. Optical Sensors 2017. 2017; 10231 ():102310.
Chicago/Turabian StyleP. Louro; João Costa; M. Vieira; M. A. Vieira; Y. Vygranenko. 2017. "Use of VLC for indoors navigation with RGB LEDs and a-SiC:H photodetector." Optical Sensors 2017 10231, no. : 102310.
P. Louro; Vitor Silva; João Costa; Manuela Vieira. Transmission of Signals Using White LEDs for VLC Application. MRS Advances 2016, 1, 3661 -3666.
AMA StyleP. Louro, Vitor Silva, João Costa, Manuela Vieira. Transmission of Signals Using White LEDs for VLC Application. MRS Advances. 2016; 1 (55):3661-3666.
Chicago/Turabian StyleP. Louro; Vitor Silva; João Costa; Manuela Vieira. 2016. "Transmission of Signals Using White LEDs for VLC Application." MRS Advances 1, no. 55: 3661-3666.
In this paper, we explore the nonlinear properties of SiC multilayer devices under UV irradiation to design an optical processor for error detection and correction, that enables reliable delivery of spectral data of four‐wave mixing over unreliable communication channels. The SiC optical processor for error detection and correction is realized by using a SiC pin/pin photodetector with UV biased optical gating elements. The relationship between the optical inputs and the corresponding digital output levels is established. Data shows that the optical bias act as a selector that picks one or more states by splitting portions of the input multi optical signals across the front and back photodiodes. Boolean operations are demonstrated optically, additional parity logic operations are performed and checked for errors together. As an example we describe an all‐optical processor for error detection and correction and then, provide an experimental demonstration of this fault tolerant reversible system. An intuitive representation with a 4 bit original string coloured message and the transmitted 7 bit string, the parity matrix, the encoding and decoding processes and the design of SiC syndrome generators are presented. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
M. A. Vieira; Vitor Silva; Paula Louro; João Costa. Optical signal processing for data error detection and correction using a-SiCH technology. physica status solidi (c) 2015, 12, 1393 -1400.
AMA StyleM. A. Vieira, Vitor Silva, Paula Louro, João Costa. Optical signal processing for data error detection and correction using a-SiCH technology. physica status solidi (c). 2015; 12 (12):1393-1400.
Chicago/Turabian StyleM. A. Vieira; Vitor Silva; Paula Louro; João Costa. 2015. "Optical signal processing for data error detection and correction using a-SiCH technology." physica status solidi (c) 12, no. 12: 1393-1400.
João Martinho; Luís Prates; João Costa. Design and Implementation of a Wireless Multiparameter Patient Monitoring System. Procedia Technology 2014, 17, 542 -549.
AMA StyleJoão Martinho, Luís Prates, João Costa. Design and Implementation of a Wireless Multiparameter Patient Monitoring System. Procedia Technology. 2014; 17 ():542-549.
Chicago/Turabian StyleJoão Martinho; Luís Prates; João Costa. 2014. "Design and Implementation of a Wireless Multiparameter Patient Monitoring System." Procedia Technology 17, no. : 542-549.
In this paper we present a monolithically integrated wavelength selector based on a double pin/pin a-SiC:H integrated optical active filter that requires optical switches to select visible wavelengths. Red, green, blue and violet pulsed communication channels are transmitted together, each one with a specific bit sequence. The combined optical signal is analyzed by reading out the generated photocurrent, under violet (400 nm) background applied either from the front or the back side of the device. The front and back backgrounds acts as channel selectors that selects one or more channels by splitting portions of the input multi-channel optical signals across the front and the back photodiodes. The transfer characteristics effects due to changes irradiation side are presented. The relationship between the optical inputs and the corresponding digital output levels is established through a 16-element look-up table to perform the optoelectronic conversion. Results show that the wavelength selector acts as a reconfigurable active filter that enhances the spectral sensitivity in a specific wavelength range and quenched it in the others, tuning a specific band. A binary weighted RGBV code that takes into account the specific weights assigned to each bit position is presented and establishes the optoelectronic functions.
Manuela Vieira; Vitor Silva; Paula Louro; João Costa. SiC monolithically integrated wavelength selector with 4 channels. MRS Proceedings 2013, 1536, 79 -84.
AMA StyleManuela Vieira, Vitor Silva, Paula Louro, João Costa. SiC monolithically integrated wavelength selector with 4 channels. MRS Proceedings. 2013; 1536 ():79-84.
Chicago/Turabian StyleManuela Vieira; Vitor Silva; Paula Louro; João Costa. 2013. "SiC monolithically integrated wavelength selector with 4 channels." MRS Proceedings 1536, no. : 79-84.
P. Louro; Manuela Vieira; João Costa; Vitor Silva; J. Patriarca; Amin Karmali. Detection of FRET signals with a wavelength sensitive device based on a-SiC:H. Applied Surface Science 2013, 275, 49 -53.
AMA StyleP. Louro, Manuela Vieira, João Costa, Vitor Silva, J. Patriarca, Amin Karmali. Detection of FRET signals with a wavelength sensitive device based on a-SiC:H. Applied Surface Science. 2013; 275 ():49-53.
Chicago/Turabian StyleP. Louro; Manuela Vieira; João Costa; Vitor Silva; J. Patriarca; Amin Karmali. 2013. "Detection of FRET signals with a wavelength sensitive device based on a-SiC:H." Applied Surface Science 275, no. : 49-53.
In this paper we demonstrate an add/drop filter based on SiC technology. Tailoring of the channel bandwidth and wavelength is experimentally demonstrated. The concept is extended to implement a 1 by 4 wavelength division multiplexer in the visible range.The add/drop filter consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n photodetector with two front and back optical gates. Tailoring the filter wavelength is achieved by applying a 400 nm background and changing front and back biased optical gates. Results show that, front background enhances the light-to-dark sensitivity of the long and medium wavelength channels and quench strongly the others. Back violet background has the opposite behavior; it enhances channel magnitude in short wavelength range and reduces it in the long ones. This nonlinearity provides the possibility for selective removal or addition of wavelengths. An optoeletronic model gives insight on the system physics and explains the light filtering properties of the add/drop filter.
M. Vieira; Paula Louro; Vitor Silva; João Costa. SiC multilayer add/drop filter for optical interconnects. MRS Proceedings 2013, 1559, 1 .
AMA StyleM. Vieira, Paula Louro, Vitor Silva, João Costa. SiC multilayer add/drop filter for optical interconnects. MRS Proceedings. 2013; 1559 ():1.
Chicago/Turabian StyleM. Vieira; Paula Louro; Vitor Silva; João Costa. 2013. "SiC multilayer add/drop filter for optical interconnects." MRS Proceedings 1559, no. : 1.
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)-í'(a-SiC: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 band-stop filter. A two-stage active circuit is presented and gives insight into the physics of the device.
M. A. Vieira; Manuela Vieira; P. Louro; Vitor Silva; João Costa; A. Fantoni. SiC Multilayer Structures as Light Controlled Photonic Active Filters. Plasmonics 2012, 8, 63 -70.
AMA StyleM. A. Vieira, Manuela Vieira, P. Louro, Vitor Silva, João Costa, A. Fantoni. SiC Multilayer Structures as Light Controlled Photonic Active Filters. Plasmonics. 2012; 8 (1):63-70.
Chicago/Turabian StyleM. A. Vieira; Manuela Vieira; P. Louro; Vitor Silva; João Costa; A. Fantoni. 2012. "SiC Multilayer Structures as Light Controlled Photonic Active Filters." Plasmonics 8, no. 1: 63-70.