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, the propagation constants, attenuation, and field distributions of dielectric waveguides clad by a thin metal layer are calculated, and it is shown that by reducing the metal thickness, the attenuation of optical modes reduces in such a way that short metal-clad devices become possible even in thin guides with thicknesses near cutoff.
Abstract: Propagation constants, attenuation, and field distributions of optical modes in dielectric waveguides clad by a thin metal layer are calculated. It is shown that by reducing the metal thickness, the attenuation of optical modes reduces in such a way that short metal-clad devices become possible even in thin guides with thicknesses near cutoff. As an application, a cutoff polarizer in symmetrical waveguides has been built by depositing a small thin silver stripe on the surface of the guide. By this structure the TE 0 mode is coupled out into the substrate, whereas the TM 0 mode is transmitted with very low losses. The best extinction ratio measured is 18 dB. The polarizer can be used as a TE 0 mode coupler into symmetrical waveguides as well.
66 citations
TL;DR: In this article, a multi-wavelength fiber laser source is demonstrated with a semiconductor optical amplifier as the gain medium, and a delayed interferometer is incorporated in the ring cavity serving as a comb-like multichannel filter.
Abstract: A multiwavelength fiber laser source is demonstrated with a semiconductor optical amplifier as the gain medium. A delayed interferometer is incorporated in the ring cavity serving as a comb-like multichannel filter. A stable 75-wavelength simultaneous operation spaced at 40 GHz with the extinction ratio of 40 dB is achieved. By tuning the cavity loss, the center wavelength of the generated lasing waveband could be varied by as much as 20 nm.
66 citations
TL;DR: In this paper, an antimonene photodetector with a strong polarization sensitivity with a broadband photoresponse was proposed, based on quantum transport calculations, and the photocurrent showed a perfect cosine dependence on the polarization angle, which originates from a second order response to the electric field of the light.
Abstract: Photodetectors based on two-dimensional materials have shown impressive performance including fast and broadband photoresponse and high responsivity However, their polarization sensitivity remains to be improved Here, we propose an antimonene photodetector having a strong polarization sensitivity with a broadband photoresponse, based on quantum transport calculations A robust photocurrent is generated for almost the whole visible range under small bias, and it saturates at a small bias voltage for most of the photon energies The photocurrent shows a perfect cosine dependence on the polarization angle, which originates from a second-order response to the electric field of the light This leads to a strong polarization sensitivity to the linearly polarized light with a large extinction ratio For a higher photon energy around 32 eV, a rather high extinction ratio greater than 100 can be achieved along with a larger photocurrent Moreover, there is an evident anisotropy between the armchair and zigzag directions, as the photocurrent intensity in the zigzag direction can be approximately 17 times larger than that in the armchair direction at a small bias These results suggest that antimonene is a promising candidate for anisotropic photodetection in the visible range especially for high frequency visible light
66 citations
TL;DR: In this article, an integrated optical switch based on liquid crystal on silicon is reported, which consists of an optical waveguide, whose core is made of nematic liquid crystal E7 infiltrated in a SiO2/Si V-groove.
Abstract: An integrated optical switch based on liquid crystal on silicon is reported. The switch consists of an optical waveguide, whose core is made of nematic liquid crystal E7 infiltrated in a SiO2/Si V-groove. The electrooptic effect allows us to control the waveguide propagation condition by means of ITO and Si electrodes. A voltage as low as 2 V applied to the driving electrodes turns the waveguide on. Since the output intensity increases with voltage, the waveguide behaves also as a variable optical attenuator. A maximum ON-OFF extinction ratio in excess of 44 dB was measured.
66 citations
TL;DR: In this article, a Mach-Zehnder interferometric all-optical switch employing intersubband transition in an InGaAs∕AlAs ∕AlSb-coupled double quantum well waveguide was developed.
Abstract: We have developed a Mach-Zehnder interferometric all-optical switch employing intersubband transition in an InGaAs∕AlAs∕AlAsSb-coupled double quantum well waveguide. The recently discovered cross-phase modulation phenomenon was utilized as the switching mechanism; the nonlinear index of refraction for transverse electric polarized light is induced by intersubband optical excitation using transverse magnetic pump light. We demonstrate the demultiplexing operation of 160Gbit∕s data signals to 10Gbit∕s using this switch. At the input control pulse energy of 8pJ, the demultiplexed signals showed an extinction ratio better than 10dB, and an error-free demultiplexing was achieved.
66 citations