Topic
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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Papers
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TL;DR: In this paper, a 10×10 micro-spatial light modulator (micro-SLM) array for phase and amplitude modulation of incident light is designed and fabricated using surface micromachining technology.
Abstract: In this paper, a 10×10 micro-spatial light modulator (micro-SLM) array for phase and amplitude modulation of incident light is designed and fabricated using surface micromachining technology. Hidden spring structure is used in order to maximize the fill-factor and minimize diffraction effect. A designed micro-SLM is composed of a mirror plate, upper electrodes, five support posts, and bottom electrodes. The spring structures are composed of four double crab leg springs for phase modulation (piston mode operation) and two torsional springs for amplitude modulation (tilt mode operation). The micro-SLM is actuated by electrostatic force generated between upper electrode and bottom electrode. In case of phase modulation, the maximum deflection length of mirror plate is designed to be 4 μm and in case of amplitude modulation, micro-SLM is designed to be capable of tilting ±5.4° to reflect incident light. The designed micro-SLM array is successfully fabricated with surface micromachining technology using thick photoresist as a sacrificial layer and aluminum as a structural material. Mirror plate and spring structure are fabricated without initial bending problem. The resulting fill-factor is about 91.7%. Static and dynamic characteristics of the fabricated micro-SLM in the case of amplitude modulation are measured with optical measurement system. In the fields of adaptive optics and pattern recognition system, SLM is used to modulate the phase and amplitude of incident light in order to correct aberration in an optical system through active control of mirror array.
49 citations
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29 Oct 1998
TL;DR: In this paper, a light guide transmits the focused light to the light modulator, where it is modulated and reflected back, via the reflective surface and light guide, to the lens.
Abstract: A retroreflecting modulator including a lens, a light guide, a light modulator, and a reflective surface. Incident light falls on the lens, where it is focused as a spot on a focal surface. The light guide transmits the focused light to the light modulator, where it is modulated and reflected back, via the reflective surface and light guide, to the lens. The lens emits the modulated light in the opposite direction as the incident light. The preferred light-receiving and focusing device is a specialty sphere lens, the preferred light guide is a fiber optic plate, and the preferred light modulator is a liquid crystal modulator. The retroreflecting modulator may be spatially-unresolvable, where a single signal modulates the light, or spatially-resolvable, where the modulation signal depends upon the direction of the incident light.
49 citations
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04 Feb 2000TL;DR: In this paper, an electrical field absorbing semiconductor optical modulator and a fabricating method for high speed optical modulators are presented. But the present method is not suitable for high-speed optical modulation with high capacitance and contact resistance.
Abstract: The present invention relates to an electrical field absorbing semiconductor optical modulator, more particularly, to a high speed semiconductor optical modulator and a fabricating method thereof. The present invention includes a high speed semiconductor optical modulator, the optical modulator formed by stacking an n-type light-wave guiding layer, a light absorbing layer, a p-type light-wave guiding layer, a p-type clad layer, and a p-type ohmic contact layer on a substrate successively, the optical modulator having a ridge structure wherein the optical modulator is an electric-field absorbing type, and wherein width W3 of the light absorbing layer is less than the width W1 of the p-type ohmic contact layer. Accordingly, the present invention enables to provide high speed optical modulation of tens of giga rate of which modulating characteristics are excellent by reducing contact resistance and capacitance, which are the major problems of ruining the characteristics of an optical modulator, simultaneously.
49 citations
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TL;DR: In this paper, optical waveguide modulation results were obtained using Wannier-Stark localization in InGaAs-InAlAs superlattices grown by molecular beam epitaxy on InP substrates.
Abstract: The authors present optical waveguide modulation results obtained using Wannier-Stark localization in InGaAs-InAlAs superlattices grown by molecular beam epitaxy on InP substrates. It is shown that the results are in good agreement with a previously reported wavefunction model. The authors experimentally investigate the modulation behavior as a function of the electroabsorptive superlattice thickness. For this purpose the authors introduce the extinction ratio per unit waveguide length and per unit electric field as a relevant figure of merit that is broadly applicable to any electroabsorptive superlattice modulator. It is shown that inhomogeneous broadening imposes an optimum thickness for the electroabsorptive superlattice. >
49 citations
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TL;DR: Comparisons between modeling and measurement results are made with good agreement obtained for both DC and AC characteristics of Mach-Zehnder silicon optical modulators based on carrier-injection.
Abstract: We present a systematic study of Mach-Zehnder silicon optical modulators based on carrier-injection. Detailed comparisons between modeling and measurement results are made with good agreement obtained for both DC and AC characteristics. A figure of merit, static VπL, as low as 0.24Vmm is achieved. The effect of carrier lifetime variation with doping concentration is explored and found to be important for the modulator characteristics.
49 citations