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Optical modulator
About: Optical modulator is a research topic. Over the lifetime, 14068 publications have been published within this topic receiving 196932 citations.
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TL;DR: It is demonstrated that considerable phase control can be achieved by integrating a single-layer graphene (SLG) with a resonant plasmonic metasurface that contains nanoscale gaps and that the polarization state of the reflected light can be by modulated by carrier injection into the SLG.
Abstract: Strong interaction of graphene with light accounts for one of its most remarkable properties: the ability to absorb 2.3% of the incident light’s energy within a single atomic layer. Free carrier injection via field-effect gating can dramatically vary the optical properties of graphene, thereby enabling fast graphene-based modulators of the light intensity. However, the very thinness of graphene makes it difficult to modulate the other fundamental property of the light wave: its optical phase. Here we demonstrate that considerable phase control can be achieved by integrating a single-layer graphene (SLG) with a resonant plasmonic metasurface that contains nanoscale gaps. By concentrating the light intensity inside of the nanogaps, the metasurface dramatically increases the coupling of light to the SLG and enables control of the phase of the reflected mid-infrared light by as much as 55° via field-effect gating. We experimentally demonstrate graphene-based phase modulators that maintain the amplitude of the...
90 citations
Patent•
22 May 1980
TL;DR: In this article, a multichannel optical sensing system for measuring temperature at a number of measuring points includes optical sensors, each of which modulates the incident light beam by light intensity modulation according to the temperature at each measuring point and returns the modulated light beam back to the same optical path.
Abstract: A multi-channel optical sensing system for measuring temperature at a number of measuring points includes optical sensors, each of which modulates the incident light beam by light intensity modulation according to the temperature at each measuring point and returns the modulated light beam back to the same optical path. The individual optical sensors are coupled to optical fibers which transmit respective light beams of different wavelengths. These optical fibers are coupled to a wavelength multiplexer/demultiplexer unit, which receives modulated light beams and supplies non-modulated light beams. This unit spectroscopically multiplexes the modulated light beams and spectroscopically demultiplexes the non-modulated light beams. It is optically coupled to another spacially spaced-apart wavelength multiplexer/demultiplexer via an optical system for transmitting light. This other wavelength multiplexer/demultiplexer unit spectroscopically demultiplexes the modulated multiplexed light beam into component light beams supplied to respective other optical fibers and also spectroscopically multiplexes light beams of different wavelengths supplied from the respective other optical fibers. To each of these other optical fibers are coupled a light source unit and modulated light and non-modulated light detecting units.
90 citations
TL;DR: A lithium niobate electro-optic phase modulator based on a coplanar waveguide ridged structure that operates up to 300 GHz is developed, able to eliminate substrate modes and observe optical sidebands over the full millimeter-wave spectrum.
Abstract: In recent years, the development of new lithium niobate electro-optic modulator designs and material processing techniques have contributed to support the increasing need for faster optical networks by considerably extending the operational bandwidth of modulators. In an effort to provide higher bandwidths for future generations of networks, we have developed a lithium niobate electro-optic phase modulator based on a coplanar waveguide ridged structure that operates up to 300 GHz. By thinning the lithium niobate substrate down to less than 39 µm, we are able to eliminate substrate modes and observe optical sidebands over the full millimeter-wave spectrum.
90 citations
TL;DR: In this paper, the authors theoretically demonstrate an advanced optical modulator based on graphene-enabled metamaterial with voltage-controllable reflectance, which can be used in optical communication systems and biomedical sensing apparatus.
Abstract: We theoretically demonstrate an advanced optical modulator based on graphene-enabled metamaterial with voltage-controllable reflectance. A significant modulation depth of the reflection coefficient is achieved through a voltage biasing of the graphene's Fermi level, leading to an almost instantaneous change in the effective permittivity of the graphene. We show that even a single graphene layer integrated into the structure of a simple metamaterial absorber enables a relative change in the reflectance as high as 361% at near-infrared frequencies. The designed modulator may be used in optical communication systems and biomedical sensing apparatus.
90 citations
TL;DR: In this paper, the complex transmittance of an Epson liquid crystal television (LCTV) is determined as a function of the video drive signal, and several operating configurations of the LCTV are established, and their usefulness as operating modes for spatial light modulators in the input and filter planes of a hybrid correlator is discussed.
Abstract: The complex transmittance of an Epson liquid crystal television (LCTV) is determined as a function of the video drive signal. Several different operating configurations of the LCTV are established, and their usefulness as operating modes for spatial light modulators in the input and filter planes of a hybrid correlator is discussed. A high-stability phase measurement scheme is developed to determine the operating curves, and this system is presented. This measurement scheme is designed so that a fully characterized LCTV could be assuredly moved into the optical correlator. This allows filters to be calculated for the correlator using the exact physical action of the modulators. The transient response of the LCTV to field-rate changes in the video signal is also presented. It is observed that the switching speed of the liquid crystal molecules is a fundamental limitation on the operating speed of these devices.
89 citations