Topic
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: To the best of the knowledge, this PBS system is one of the best broadband PBSs with an ER as high as ∼42 dB and a low IL below 1 dB around the central wavelength, and experimentally demonstrated using edge-coupling.
Abstract: We report on the design and experimental demonstration of a broadband silicon polarization beam splitter (PBS) with a high extinction ratio (ER)≥30 dB. This was achieved using triple-bent-waveguide directional coupling in a single PBS, and cascaded PBS topology. For the single PBS, the bandwidths for an ER≥30 dB are 20 nm for the quasi-TE mode, and 70 nm for the quasi-TM mode when a broadband light source (1520–1610 nm) was employed. The insertion loss (IL) varies from 0.2 to 1 dB for the quasi-TE mode and 0.2–2 dB for the quasi-TM mode. The cascaded PBS improved the bandwidth of the quasi-TE mode for an ER≥30 dB to 90 nm, with a low IL of 0.2–2 dB. To the best of our knowledge, our PBS system is one of the best broadband PBSs with an ER as high as ∼42 dB and a low IL below 1 dB around the central wavelength, and experimentally demonstrated using edge-coupling.
51 citations
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TL;DR: Using terahertz time-domain spectroscopy (THz-TDS), a fabricated polarizer is characterized, with extinction ratios greater than 50 dB and transmission losses below 1 dB reported in the 0.2-1.1 THz frequency range.
Abstract: A thin-film terahertz polarizer is proposed and realized via a tunable bilayer metal wire-grid structure to achieve high extinction ratios and good transmission. The polarizer is fabricated on top of a thin silica layer by standard micro-fabrication techniques to eliminate the multireflection effects. The tunable alignment of the bilayer aluminum-wire grid structure enables tailoring of the extinction ratio and transmission characteristics. Using terahertz time-domain spectroscopy (THz-TDS), a fabricated polarizer is characterized, with extinction ratios greater than 50 dB and transmission losses below 1 dB reported in the 0.2–1.1 THz frequency range. These characteristics can be improved by further tuning the polarizer parameters such as the pitch, metal film thickness, and lateral displacement.
51 citations
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TL;DR: An ultra-compact chiral metamaterial (CMM) using triple-layer twisted split-ring resonators (TSRRs) structure was proposed, which can function as a multi-band circular polarizer.
Abstract: An ultra-compact chiral metamaterial (CMM) using triple-layer twisted split-ring resonators (TSRRs) structure was proposed, which can function as a multi-band circular polarizer. This ultra-compact structure CMM can convert an incident linearly y-polarized (x-polarized) wave propagating along thez(+z) direction to the transmitted left circularly polarized (LCP) waves at 7.28 GHz, 13.22 GHz and 15.49 GHz while the right circularly polarized (RCP) waves are at 9.48 GHz simultaneously. In addition, the large polarization extinction ratio (PER) of more than 20 dB across four resonance frequencies can be achieved. The experiment results are in good agreement with the numerical simulation results. The surface current distributions of the structure are analyzed to illustrate this linear to circular polarization conversion. The unit cell structure is extremely small both in longitudinal and transverse directions. Good performances and compact design of this CMM suggest promising applications in circular polarizers that need to be integrated with other compact devices.
51 citations
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TL;DR: F-P resonators demonstrated here show advantages of small size, good resonance, easy fabrication, tunability, and easy integration with fiber systems.
Abstract: We demonstrate all fiber Fabry-Perot resonators (F-P resonators) based on Sagnac loop mirrors assembled with tellurite microfibers. As-assembled F-P resonators, with dimensions of hundreds of micrometers, show clear resonant responses with typical quality factor of about 5700, free spectral range of about 1 nm, and a maximum extinction ratio of 18 dB. The reflectivity of the loop mirror and the effective cavity length of the F-P resonator can be tuned by micromanipulation under an optical microscope. F-P resonators demonstrated here show advantages of small size, good resonance, easy fabrication, tunability, and easy integration with fiber systems.
51 citations
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TL;DR: An integrated reconfigurable optical add-drop multiplexer (ROADM) for mode-division-multiplexing systems is proposed and demonstrated for the first time, to the best of the authors' knowledge.
Abstract: An integrated reconfigurable optical add-drop multiplexer (ROADM) for mode-division-multiplexing systems is proposed and demonstrated for the first time, to the best of our knowledge. The present ROADM with four mode-channels is composed of a four-channel mode demultiplexer, four identical 2×2 thermo-optic Mach-Zehnder switches (MZSs), and a four-channel mode multiplexer, which are integrated monolithically on silicon. All the devices are designed for operation with TM polarization. The ROADM can add/drop any one of the mode channels freely by thermally turning on/off the corresponding MZS. For the added/dropped mode-channels, the excess loss is 1-5 dB, and the extinction ratio is 15-20 dB in the wavelength range of 1535-1565 nm.
50 citations