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: In this paper, a Mach-Zehnder electro-optic polymer amplitude modulator is fabricated by a simple and high-throughput soft-stamp replica-molding technique.
Abstract: A Mach-Zehnder electro-optic polymer amplitude modulator is fabricated by a simple and high-throughput soft-stamp replica-molding technique. The modulator structure incorporates the highly nonlinear and stable chromophore, AJL8, doped in amorphous polycarbonate. Single-arm phase-retardation results in a halfwave voltage (V-pi) of 8.4 V at 1600 nm. The on/off extinction ratio is better than 19 dB, resulting from precise Y-branch power splitters and good waveguide uniformity. These results indicate that the simple fabrication process allows for good optical performance from high-fidelity replicas of the original master devices.
75 citations
TL;DR: By fabricating simple micro-ribbon arrays of topological insulator Bi2Se3, an unprecedentedly large modulation depth of 2,400% is reported, which was possible because the extinction spectrum is nearly zero due to the Fano-like plasmon–phonon-destructive interference, thereby contributing an extremely small denominator to the extinction ratio.
Abstract: Modulating light via coherent charge oscillations in solids is the subject of intense research topics in opto-plasmonics. Although a variety of methods are proposed to increase such modulation efficiency, one central challenge is to achieve a high modulation depth (defined by a ratio of extinction with/without light) under small photon-flux injection, which becomes a fundamental trade-off issue both in metals and semiconductors. Here, by fabricating simple micro-ribbon arrays of topological insulator Bi2Se3, we report an unprecedentedly large modulation depth of 2,400% at 1.5 THz with very low optical fluence of 45 μJ cm(-2). This was possible, first because the extinction spectrum is nearly zero due to the Fano-like plasmon-phonon-destructive interference, thereby contributing an extremely small denominator to the extinction ratio. Second, the numerator of the extinction ratio is markedly increased due to the photoinduced formation of massive two-dimensional electron gas below the topological surface states, which is another contributor to the ultra-high modulation depth.
74 citations
TL;DR: Mie scattering lidar was used to observe aerosol extinction coefficient profiles in the troposphere over Tsukuba, Japan, for three years from March 1990 to February 1993, and data obtained in fair weather were analyzed.
Abstract: Mie scattering lidar was used to observe aerosol extinction coefficient profiles in the troposphere over Tsukuba (140 E, 36 N), Japan, for three years from March 1990 to February 1993, and data obtained in fair weather were analyzed. The lidar measurements were made by a vertical scanning mode to generate profiles of extinction coefficients from the lidar level to a 12-km altitude. The extinction coefficients were derived from the lidar signals using a two-component (air molecule and aerosol) lidar equation, in which the ratio of aerosol extinction to backscattering was assumed to be constant. Seasonal average profiles were derived from individual profiles. Three-year average profiles were also calculated and modeled using mathematical expressions. The model profile assumed (1) a constant extinction ratio in the atmospheric boundary layer (ABL), (2) an exponentially decreasing extinction ratio above the ABL, and (3) a constant extinction ratio in the upper troposphere where the extinction ratio can be defined as the ratio of the aerosol extinction coefficient to the air molecule extinction coefficient. The extinction ratios both in the ABL and in the upper troposphere and the scale height that was used to express the exponential decrease were used as three unknown parameters. Seasonal variation of optical thickness that was obtained by integrating extinction coefficients with height was also investigated.
74 citations
TL;DR: In this article, an electro-optically tunable switch using tenth-order coupled-microring resonators in silicon-on-insulator using complementary metaloxide-semiconductor fabrication technology was demonstrated.
Abstract: We demonstrate an electro-optically (EO) tunable switch using tenth-order coupled-microring resonators in silicon-on-insulator using complementary metal-oxide-semiconductor fabrication technology. The measured drop-port transmission spectra show box-like transmission passband with ~100-GHz bandwidth and ~50-dB extinction ratio. With a DC voltage supply to the integrated p-i-n diodes surrounding the microrings, the optical switch shows, respectively, ~10 and ~45-dB on/off ratios from throughputand drop-port. The measured EO switching times are ~1 ns upon a 1.2-Vpp low-speed driving signal and a DC power consumption of ~37 mW. Up to 30-Gb/s pseudorandom binary sequence (231-1) signal transmissions suggest high-data-rate signal switching capability.
74 citations
TL;DR: A novel ultracompact (5 μm) hybrid plasmonic polarization rotator operating at telecommunication wavelength for integrated silicon photonic circuits with low total insertion losses is proposed.
Abstract: We propose a novel ultracompact (5 μm) hybrid plasmonic polarization rotator operating at telecommunication wavelength for integrated silicon photonic circuits. The polarization mode of a silicon waveguide is rotated with >14 dB polarization extinction ratio and low total insertion losses of 2.1 dB.
74 citations