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Characterization of beam splitters in the calibration of a six-channel Stokes polarimeter
摘要： Polarization distortion in a beam splitter is a phenomenon where the polarization state of output light deviates from the theoretical expectation, which is inevitable and will result in significant errors in the optical systems. A theoretical analysis method based on Mueller matrix ellipsometry is proposed for characterizing the beam splitters and the application in the calibration of a six-channel Stokes polarimeter (SP) is shown. In this study, polarization distortions in the beam splitters including depolarization, linear birefringence, circular birefringence, linear dichroism, and circular dichroism have been considered. With the proposed method, the beam splitters are characterized by the polarization distortions and the effective optical parameters extracted. In our experiment, the Mueller matrices of two different commonly used beam splitters measured by a commercial Mueller matrix ellipsometer (MME) are consistently fitted by the proposed method and the residual errors have shown improvement compared to the conventional methods. A practical application of the proposed method is exhibited by calibrating a SP system containing two non-polarization beam splitters and three polarization beam splitters. With the proposed method introduced, the general error of the measured Stokes vector can be reduced from 3% to 1%, and the errors of the thickness measurement of standard SiO2 thin film samples are within 1 nm compared with the results reported by a commercial MME.
关键词： beam splitter,characterization,calibration,Stokes polarimeter,polarization distortion
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Optimization of a Polarization Beam Splitter for Broadband Operation using a Genetic Algorithm
摘要： We present a design method for a polarization beam splitter for broadband operation based on a genetic algorithm (GA). The devices are segmented into short sections, where the geometric parameters for each device are determined using a GA.
关键词： genetic algorithm,silicon photonics,directional coupler,broadband,optimization,beam splitter
更新于2025-09-23 15:22:29
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Design of silicon waveguide polarization beam splitter based on reversed ?? <i>?2</i> directional coupler
摘要： We report a directional coupler type polarization beam splitter using silicon waveguides designed for 1550–1600 nm wavelengths. The device uses the coupling strength difference between the TE and TM modes. We use a reversed Δβ structure to achieve a wide operational wavelength range. The gap between the waveguides needs to be wide enough to attain a sufficient extinction ratio for the TE mode. Simulation results show that an over 100 nm operational 20 dB extinction ratio wavelength range can be attained at 1520–1620 nm wavelengths by this simple structure. The fabrication width tolerance exceeds 10 nm which is enough for foundry processes.
关键词： polarization beam splitter,silicon waveguide,directional coupler,TE and TM modes,reversed Δβ structure
更新于2025-09-23 15:21:01
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TERAHERTZ BEAM SPLITTER BASED ON I-SHAPED METASURFACE
摘要： A linear polarization beam splitter operating in terahertz band is proposed and experimentally veri?ed in this paper. The unit cell of the beam splitter is composed of the top “I” type metal pattern, the middle dielectric layer, and the bottom metal layer. Each subarray structure of the device consists of four unit cells that rotate progressively at an angle of 45?. The horizontal and vertical sub-arrays form the gradient metasurface of 4 × 4. The incident linear polarized terahertz wave is re?ected by the device and divided into four beams with approximately equal power, while having di?erent propagating directions in the 0.18–0.30 THz band. The proposed terahertz beam splitter has the advantages of small size, low cost, and easy processing, and it can be applied to terahertz stealth and terahertz imaging.
关键词： terahertz,polarization,beam splitter,metasurface
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Compact Polarization Beam Splitter Based on a 3-Waveguide Directional Coupler with Broad Bandwidth Performance
摘要： Compact polarization beam splitter based on a 3-waveguide directional coupler with broad bandwidth performance
关键词： slot waveguide,directional coupler,Polarization beam splitter
更新于2025-09-23 15:19:57
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Continuous variable quantum teleportation via entangled Gaussian state generated by a linear beam splitter
摘要： We theoretically implement the protocol of continuous variable quantum teleportation wherein Alice and Bob share a state built by a linear beam splitter as general two-mode Gaussian entangled state. Using the non-classicality and purity of the two single-mode Gaussian states employed initially at the input of the beam splitter, the unknown state teleportation protocol is explicitly implemented in terms of squeezing and phase space quadratures. We show that fidelity of the teleported state is maximal when the gain factor g is equal to 1 and gradually decreases when g deviates from 1 on either side. We further find that teleportation fidelity decreases when one of the input states of the beam splitter is replaced by the state of thermal photons.
关键词： quantum teleportation,entanglement,Gaussian state,beam splitter,continuous variable
更新于2025-09-23 15:19:57
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Laser encoder system for X-Y positioning stage
摘要： In this investigation, a novel opto-mechatronics design of linear Laser encoder system which can eliminate geometrical errors of X-Y positioning stage was proposed. The eliminated geometrical errors, which are squareness error, straightness error and Abbe error, can be reduced by this Laser encoder system. Those errors are induced by the mechanical components and assemblies. In this design, a pentaprism beam splitter was employed to divide the laser beam into two encoder axes which are perpendicular to each other. For this arrangement, a real zero point of the positioning stage was set inside the pentaprism beam splitter. Therefore, those specific geometrical errors can be minimized by the proposed system. In this research, the design of the opto-mechatronics structure and its theoretical simulations will be studied. The experimental results which were obtained in the ordinary environment revealed that the resolution of the proposed positioning stage is about 15.8 nm. In addition, the maximum standard deviation of static positioning error is about 50 nm. The Laser encoder system presented in this study is recommended to be used in the precision machinery and semiconductor industries for the precision positioning purpose.
关键词： Geometrical error,Positioning stage,Interferometer,Precision positioning,Laser encoder system,Pentaprism beam splitter
更新于2025-09-19 17:13:59
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Suppression of amplitude fluctuation in Brillouin optical fiber reflectometry employing polarization beam splitter and pre-amplification technique
摘要： We propose and validate the suppression effect on amplitude fluctuation in Brillouin optical time domain reflectometry sensing system with a polarization beam splitter and pre-amplification technique. The p- and s-components of local oscillator interfere respectively with two halves of Brillouin scattering amplified by a Erbium doped fiber amplifier. Theoretical analysis indicates that the polarization influence on the beat amplitude is eliminated with the proposed scheme; and experimental results show that the amplitude variation along the sensing fiber could be extracted accurately, and the temperature sensing error is about 5%. The proposed method is helpful to improve the measurement accuracy of the BOTDR sensing system.
关键词： Pre-amplification technique,Polarization beam splitter,Brillouin optical time domain reflectometry,Amplitude fluctuation suppression,sensing system
更新于2025-09-19 17:13:59
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Angular Dependence of Photonic Crystal Coupled to Photovoltaic Solar Cell
摘要： Photonic crystals have the advantage of minimizing thermal losses from solar cells, reflecting the solar radiation that is not absorbed by the photovoltaic device. To optimize this optical response, photonic crystals are designed considering the relative position of the Bragg peak and the bandgap of the solar cell, under normal incident irradiation conditions. The aim of this research article was to determine experimentally the optical limits of a solar cell coupled to a photonic crystal acting as beam splitter. For that purpose, the photovoltaic system was characterized under indoor and outdoor conditions; angular dependence of the irradiation source was determined in each case, and both results were compared with good agreement. Moreover, other parameters such as irradiation spectrum and polarization of the light were investigated. The main conclusion is that photovoltaic performance is highly affected by the Bragg peak shifting and the profile is distorted, due to the angular dependence with the sun. These experimental limits must be considered at the early design stage to avoid performance losses.
关键词： spectral radiation,solar energy,photovoltaic,photonic crystal,beam splitter,polarization
更新于2025-09-16 10:30:52
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Realization of a compact broadband polarization beam splitter using the three-waveguide coupler
摘要： A compact broadband polarization beam splitter is designed and experimentally demonstrated based on a silicon-nitride-assisted three-waveguide coupler. With the help of coving a layer of silicon nitride on the center bridged silicon waveguide, the phase matching is met for the TM mode but not for the TE mode. The final optimized device length is only 7 μm, and the polarization beam splitter has the high extinction ratios of more than 30 dB for the TE mode and that of more than 20 dB for the TM mode in the wavelength ranging from 1.5 μm to 1.6 μm. And the corresponding insertion losses are less than 0.06 dB and 0.35 dB, respectively. The experimental measurement results also show the polarization beam splitter has good performances.
关键词： integrated optics,Silicon photonics,three-waveguide coupler,polarization beam splitter
更新于2025-09-12 10:27:22