ABSTRACT This paper describes a novel variable optical attenuator using a phase variation of a po... more ABSTRACT This paper describes a novel variable optical attenuator using a phase variation of a polymer dispersed liquid crystal in a cell with an adequate photo-resist pattern. This component is inserted between two collimated single-mode fibers and tested at telecom wavelengths. An optical attenuation range of 22 dB is obtained with a maximum polarization dependence loss (PDL) of 0.18 dB with a new phase pattern.
2010 IEEE Frontiers in Education Conference (FIE), 2010
Engineering educational programs increasingly rely on project-based learning. Within, it is cruci... more Engineering educational programs increasingly rely on project-based learning. Within, it is crucial to early present to students intended learning outcomes from the outset of large projects. However, even if well formulated, many outcome-related project learning objectives are not properly understood by students out of experiences.
2006 International Conference on Photonics in Switching, 2006
A novel 1×2 wavelength routing switch is introduced and analyzed. It is based on a tunable hybrid... more A novel 1×2 wavelength routing switch is introduced and analyzed. It is based on a tunable hybrid liquid-crystal Solc filter and a polarization beamsplitter. The device can be set into the bar state for an arbitrary subset of WDM channels while remaining in the cross state for the rest of channels. This is achieved via a tuning voltage applied to
In this work, an advanced multifunctional optical switch based on multimode fibers is proposed. I... more In this work, an advanced multifunctional optical switch based on multimode fibers is proposed. It can work as a 3 × 1 optical multiplexer/combiner, a 2 × 2 optical switch, a variable optical attenuator and a variable optical power splitter. All these functionalities can be developed in the same device without any hardware modification, only by using the proper ports and control electronics. The proposed switch has been developed for being used in the visible and near infrared wavelength range: 450-650 nm for optical fiber automobile applications, 650-850 nm for home broadband applications; and 850-1300 nm for multimode fiber access networks. Up to three different types of twisted nematic liquid crystal cells have been designed and fabricated for fulfilling these different wavelength ranges as part of the proposed device. The multifunctional switch has been implemented and experimentally tested. Crosstalk usually better than − 15 dB at 532 nm, 660 nm and 850 nm, in any state has been measured. Switching is achieved at voltage levels of 4 Vrms. Fiber to fiber insertion losses when operating as a 2 × 2 optical switch, range from 10 to 15 dB within 200 nm wavelength range; with a non-optimized optics for collimation and coupling.
This paper describes the design of a polarisation controller using a nematic liquid crystal in th... more This paper describes the design of a polarisation controller using a nematic liquid crystal in the infrared. Theoretical comparison of parallel and twisted structures is made. Our samples reach 30 dB contrast and 1.4 dB insertion loss. Twisted nematic cells were used to perform a 4 × 4 strictly non-blocking optical switch at 1.5 μm with 15.2 dB fibre to
We report a convenient and accurate technique for measuring the optical path difference induced b... more We report a convenient and accurate technique for measuring the optical path difference induced by a birefringent crystal. The method is based on the transmission of a low-frequency signal by the electro-optic amplitude modulation of a monochromatic light source. The linear superposition principle of the induced birefringence and the electro-optic effect are employed in the analysis of the optical parameters. Birefringence measurements at the wavelength 0.6328 lm for some common nematic liquid crystal cells are presented. The measurement accuracy is close to 10 À3 . In addition, the phase shift of a twisted-nematic liquid crystal spatial light modulator, which is now widely used in optical processing systems, is determined as a function of the gray-scale level.
ABSTRACT To improve variable optical attenuator (VOA) performance, the object of this study is to... more ABSTRACT To improve variable optical attenuator (VOA) performance, the object of this study is to know the most appropriate structure of a polymer-dispersed liquid crystal (PDLC) composite. In fact, using its electro-optical properties, PDLC can be inserted between two optical fibers for adjusting the coupling efficiency. We utilize here the photopolymerization-induced phase separation (PIPS) method as a fabrication process. Furthermore, we present a theoretical analysis of light scattering by anisotropic spheres based on the anomalous diffraction approach (ADA) and compare this model with some experimental results. The optical attenuation (OA) range is optimized in the case where LC, the droplets nematic directors, are randomly oriented. If the nematic directors have a quasiprivileged direction, we demonstrate that PDLC transmission depends on the incident light polarization. Polarization-dependent loss (PDL) and OA behaviors are then studied at the 1.55-μm wavelength according to several parameters such as PDLC thickness, LC droplet size, and the device driving voltage.
ABSTRACT This paper describes a novel variable optical attenuator using a phase variation of a po... more ABSTRACT This paper describes a novel variable optical attenuator using a phase variation of a polymer dispersed liquid crystal in a cell with an adequate photo-resist pattern. This component is inserted between two collimated single-mode fibers and tested at telecom wavelengths. An optical attenuation range of 22 dB is obtained with a maximum polarization dependence loss (PDL) of 0.18 dB with a new phase pattern.
2010 IEEE Frontiers in Education Conference (FIE), 2010
Engineering educational programs increasingly rely on project-based learning. Within, it is cruci... more Engineering educational programs increasingly rely on project-based learning. Within, it is crucial to early present to students intended learning outcomes from the outset of large projects. However, even if well formulated, many outcome-related project learning objectives are not properly understood by students out of experiences.
2006 International Conference on Photonics in Switching, 2006
A novel 1×2 wavelength routing switch is introduced and analyzed. It is based on a tunable hybrid... more A novel 1×2 wavelength routing switch is introduced and analyzed. It is based on a tunable hybrid liquid-crystal Solc filter and a polarization beamsplitter. The device can be set into the bar state for an arbitrary subset of WDM channels while remaining in the cross state for the rest of channels. This is achieved via a tuning voltage applied to
In this work, an advanced multifunctional optical switch based on multimode fibers is proposed. I... more In this work, an advanced multifunctional optical switch based on multimode fibers is proposed. It can work as a 3 × 1 optical multiplexer/combiner, a 2 × 2 optical switch, a variable optical attenuator and a variable optical power splitter. All these functionalities can be developed in the same device without any hardware modification, only by using the proper ports and control electronics. The proposed switch has been developed for being used in the visible and near infrared wavelength range: 450-650 nm for optical fiber automobile applications, 650-850 nm for home broadband applications; and 850-1300 nm for multimode fiber access networks. Up to three different types of twisted nematic liquid crystal cells have been designed and fabricated for fulfilling these different wavelength ranges as part of the proposed device. The multifunctional switch has been implemented and experimentally tested. Crosstalk usually better than − 15 dB at 532 nm, 660 nm and 850 nm, in any state has been measured. Switching is achieved at voltage levels of 4 Vrms. Fiber to fiber insertion losses when operating as a 2 × 2 optical switch, range from 10 to 15 dB within 200 nm wavelength range; with a non-optimized optics for collimation and coupling.
This paper describes the design of a polarisation controller using a nematic liquid crystal in th... more This paper describes the design of a polarisation controller using a nematic liquid crystal in the infrared. Theoretical comparison of parallel and twisted structures is made. Our samples reach 30 dB contrast and 1.4 dB insertion loss. Twisted nematic cells were used to perform a 4 × 4 strictly non-blocking optical switch at 1.5 μm with 15.2 dB fibre to
We report a convenient and accurate technique for measuring the optical path difference induced b... more We report a convenient and accurate technique for measuring the optical path difference induced by a birefringent crystal. The method is based on the transmission of a low-frequency signal by the electro-optic amplitude modulation of a monochromatic light source. The linear superposition principle of the induced birefringence and the electro-optic effect are employed in the analysis of the optical parameters. Birefringence measurements at the wavelength 0.6328 lm for some common nematic liquid crystal cells are presented. The measurement accuracy is close to 10 À3 . In addition, the phase shift of a twisted-nematic liquid crystal spatial light modulator, which is now widely used in optical processing systems, is determined as a function of the gray-scale level.
ABSTRACT To improve variable optical attenuator (VOA) performance, the object of this study is to... more ABSTRACT To improve variable optical attenuator (VOA) performance, the object of this study is to know the most appropriate structure of a polymer-dispersed liquid crystal (PDLC) composite. In fact, using its electro-optical properties, PDLC can be inserted between two optical fibers for adjusting the coupling efficiency. We utilize here the photopolymerization-induced phase separation (PIPS) method as a fabrication process. Furthermore, we present a theoretical analysis of light scattering by anisotropic spheres based on the anomalous diffraction approach (ADA) and compare this model with some experimental results. The optical attenuation (OA) range is optimized in the case where LC, the droplets nematic directors, are randomly oriented. If the nematic directors have a quasiprivileged direction, we demonstrate that PDLC transmission depends on the incident light polarization. Polarization-dependent loss (PDL) and OA behaviors are then studied at the 1.55-μm wavelength according to several parameters such as PDLC thickness, LC droplet size, and the device driving voltage.
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Papers by Bruno Vinouze