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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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Journal ArticleDOI
TL;DR: A novel polarization beam splitter using a two-layer grating coupler that can directly couple the normally incident light from fiber into two separate waveguides according to their polarization states while splitting them is proposed and demonstrated.
Abstract: A novel polarization beam splitter using a two-layer grating coupler is proposed and demonstrated. It can directly couple the normally incident light from fiber into two separate waveguides according to their polarization states while splitting them. It realizes high coupling efficiency and a good extinction ratio by using binary blazed grating couplers. The coupling length is less than 14 microm. The extinction ratio is better than 20 dB for both polarizations over a 40 nm wavelength range, and the coupling efficiencies for the two layers are 58% and 50%.

137 citations

Journal ArticleDOI
TL;DR: Use of the same GeSi composition and device structure allows efficient monolithic process integration of the modulators and the photodetectors on an SOI platform.
Abstract: We present a design of monolithically integrated GeSi electroabsorption modulators and photodetectors for electronic-photonic integrated circuits on a silicon-on-insulator (SOI) platform. The GeSi electroabsorption modulator is based on the Franz-Keldysh effect, and the GeSi composition is chosen for optimal performance around 1550 nm. The designed modulator device is butt-coupled to Si(core)/SiO(2)(cladding) high index contrast waveguides, and has a predicted 3 dB bandwidth of >50 GHz and an extinction ratio of 10 dB. The same device structure can also be used for a waveguide-coupled photodetector with a predicted responsivity of > 1 A/W and a 3 dB bandwidth of > 35 GHz. Use of the same GeSi composition and device structure allows efficient monolithic process integration of the modulators and the photodetectors on an SOI platform.

137 citations

Journal ArticleDOI
TL;DR: 4-port, electrically tunable photonic filters using silicon contra-directional couplers (contra-DCs) with uniform and phase-shifted waveguide Bragg gratings are demonstrated, with great potential for applications such as wavelength-division multiplexing networks and optical signal processing.
Abstract: We demonstrate, in both theory and experiment, 4-port, electrically tunable photonic filters using silicon contra-directional couplers (contra-DCs) with uniform and phase-shifted waveguide Bragg gratings. Numerical analysis, including both intra- and inter-waveguide couplings, is performed using coupled-mode theory and the transfer-matrix method. The contra-DC devices were fabricated by a CMOS-photonics manufacturing foundry and are electrically tunable using free-carrier injection. A 4-port, grating-based photonic resonator has been obtained using the phase-shifted contra-DC, showing a resonant peak with a 3-dB bandwidth of 0.2 nm and an extinction ratio of 24 dB. These contra-DC devices enable on-chip integration of Bragg-grating-defined functions without using circulators and have great potential for applications such as wavelength-division multiplexing networks and optical signal processing.

136 citations

Journal ArticleDOI
TL;DR: A novel type of optical polarizer based on silicon-on-insulator shallowly-etched ridge waveguide is designed, fabricated and characterized and is compact, broad-band, and easy-fabricated.
Abstract: A new way to make broadband polarizers on silicon-on-insulator (SOI) waveguides is proposed, analyzed and characterized. The characteristics of the eigenmodes in a shallowly-etched SOI ridge optical waveguide are analyzed by using a full-vectorial finite-different method (FV-FDM) mode solver. The theoretical calculation shows that the loss of TE fundamental mode could be made very low while at the same time the TM fundamental mode has very large leakage loss, which is strongly dependent on the trench width. The leakage loss of the TM fundamental mode changes quasi-periodically as the trench width w(tr) varies. The formula of the period ∆w(tr) is given. By utilizing the huge polarization dependent loss of this kind of waveguide, a compact and simple optical polarizer based on a straight waveguide was demonstrated. The polarizer is fabricated on a 700 nm-thick SOI wafer and then characterized by using a free-space optical system. The measured extinction ratio is as high as 25 dB over a 100 nm wavelength range for a 1 mm-long polarizer.

135 citations

Journal ArticleDOI
TL;DR: In this article, a dual-band linear-to-circular polarization converter (LCPC) based on a single-layer dielectric substrate is proposed, which consists of two identical metallic layers with a combination of a connected Jerusalem cross (JC) and an I-type dipole for each layer.
Abstract: A dual-band linear-to-circular polarization converter (LCPC) based on a single-layer dielectric substrate is proposed. The element of the converter consists of two identical metallic layers with a combination of a connected Jerusalem cross (JC) and an “I”-type dipole for each layer. The proposed converter is designed by using an equivalent circuit model (ECM). Left-handed circularly polarized (LHCP) and right-handed circularly polarized (RHCP) beams can be, respectively, generated at ${K}$ -band and Ka -band excited by a linearly polarized (LP) wave tilted 45° relative to the ${x}$ - and ${y}$ -directions of the converter. In addition, the converter covers two operation bands for ${K}$ -/ Ka -band satellite communications with high conversion efficiency and low polarization extinction ratio (PER). After full-wave optimization, the proposed converter is fabricated and measured. The measured results show a good agreement with the simulated ones. Even though there exists a tradeoff between the angular stability and the bandwidth of the dual-band LCPCs, the measured axial ratio (AR) remains stable in the lower operation band and a slight fluctuation in the higher band with the incident angle of 20°.

135 citations


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