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Extinction ratio

About: Extinction ratio is a research topic. Over the lifetime, 8541 publications have been published within this topic receiving 111908 citations.


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TL;DR: In this paper, the authors introduced a novel configuration for long-range Brillouin optical time domain analysis (BOTDA) sensors that is based on shaping the pump pulses in the radio frequency instead of the optical domain.
Abstract: We introduce a novel configuration for long-range Brillouin optical time domain analysis (BOTDA) sensors that is based on shaping the pump pulses in the radio frequency instead of the optical domain. This results in a simplified setup that uses just one standard intensity modulator to generate pulses with an extremely high extinction ratio (60 dB in our experiments). We develop a theoretical model for Brillouin interaction in long-distance BOTDA and use simulations to demonstrate that the availability of such pure pulses completely suppresses measurement errors caused by pulse leakage. Finally, experimental results are shown to confirm theoretical predictions. A 25 km fibre is measured with our system and the results compared to those obtained using pump pulses with lower extinction ratios.

33 citations

Journal ArticleDOI
TL;DR: In this paper, a horizontal slot Si-VO2-Si optical waveguide is proposed and its optical properties are investigated, and it is shown that the effective index and the propagation loss of the proposed waveguide undergo substantial changes upon the VO2 transition from insulating to metallic phase.
Abstract: In this paper, a horizontal slot Si–VO2–Si optical waveguide is proposed and its optical properties are investigated. Numerical simulation results show that the effective index and the propagation loss of the proposed waveguide undergo substantial changes upon the VO2 transition from insulating to metallic phase. The effective index and the propagation loss variations of the proposed waveguide are then maximized by optimizing waveguide dimensions. It is shown that 0.226 change in the effective index (Δ n eff = 0.226) and 30 dB/ μ m change in the propagation loss (Δ l dB = 30 dB/μm) are achievable using the optimum dimensions. These extraordinary variations in waveguide properties recommend the proposed waveguide as an excellent candidate for optical active device realization. To investigate these applications, performance parameters of the proposed waveguide are further studied in terms of the transition speed and the power consumption. In these studies, the VO2 phase transition is assumed to be actuated by applying an electric field. Two examples of optical active devices based on the proposed waveguide are then presented: an electro-absorption modulator and a 1 × 2 directional coupler optical switch. Finite-difference time-domain simulation of the proposed devices shows very high extinction ratio of 21 dB along the ultrasmall propagation length of 1 μ m, for the proposed electro-absorption modulator, and high extinction ratios of ∼18.5 dB and ∼8.6 dB in off - and on -state of the proposed 1 × 2 switch, which has very small length of ∼6 μ m. Further simulations also show interesting properties of the proposed devices in terms of the power consumption, insertion loss, and bandwidth.

33 citations

Journal ArticleDOI
Jianshuai Wang1, Li Pei1, Sijun Weng1, Liangying Wu1, Jing Li1, Tigang Ning1 
TL;DR: An ultrashort polarization beam splitter based on liquid-filled dual-core photonic crystal fiber based on DCPCF shows a great advantage when being integrated in ultra-compact optical systems.
Abstract: An ultrashort polarization beam splitter (PBS) is proposed based on liquid-filled dual-core photonic crystal fiber (DCPCF). The two cores of DCPCF are formed by two side elliptical holes and a central circular hole in the horizontal direction. The properties of the PBS are analyzed first with a non-filled DCPCF by the finite element method. Then, the performances of the PBS are discussed when the DCPCF is filled with liquids in the central hole. As a result, an ultrashort PBS is realized with a length of 78 μm when glycerol solution with a concentration of 37% is filled in the central hole. In this case, an extinction ratio of 87 dB is obtained at 1550 nm wavelength. The significantly short device shows a great advantage when being integrated in ultra-compact optical systems.

33 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate the first transverse magnetic (TM) pass waveguide polarizer suitable for integrated optic or fiber optic geometries and illustrate these novel polarizing properties on ion-exchanged planar waveguides overlayed with a 5-nm-mass thick silver film.
Abstract: We demonstrate the first transverse magnetic (TM) pass waveguide polarizer suitable for integrated optic or fiber optic geometries. The polarizing properties of waveguides incorporating an ultrathin discontinuous silver film are due to excitation of a localized surface plasmon mode. The polarizers have a large bandwidth (≳100 nm), high extinction ratios, and do not rely on sensitive phase matching conditions. We illustrate these novel polarizing properties on ion‐exchanged planar waveguides overlayed with a 5‐nm‐mass thick silver film. The measured extinction ratio was 35 dB/mm at 836 nm with 2 dB/mm loss for the TM polarization. The theoretical analysis of the film properties and waveguide propagation losses is compared with the experiments.

33 citations

Journal ArticleDOI
TL;DR: Graphene-assisted all-optical control of a fiber Bragg grating enables in-fiber optical bistability and switching and allows the implementation of optical switching with an extinction ratio exceeding 20 dB and a response time in tens of milliseconds.
Abstract: We report a graphene-assisted all-optical control of a fiber Bragg grating (FBG), which enables in-fiber optical bistability and switching. With an optical pump, a micro-FBG wrapped by graphene evolves into chirped and phase-shifted FBGs, whose characteristic wavelengths and bandwidths could be controlled by the pump power. Optical bistability and multistability are achieved in the controlled FBG based on a shifted Bragg reflection or Fabry-Perot-type resonance, which allow the implementation of optical switching with an extinction ratio exceeding 20 dB and a response time in tens of milliseconds.

33 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023187
2022429
2021371
2020449
2019468
2018441