Optical modulator

About: Optical modulator is a research topic. Over the lifetime, 14068 publications have been published within this topic receiving 196932 citations.

Analysis of ring resonator-based traveling-wave modulators

Abstract: We analyze ring resonator-based traveling-wave modulators that show high modulation efficiency at frequencies around multiples of the free spectral range. The modulators have better tolerance for the optical/microwave velocity mismatch and the loss of the microwave transmission line than traveling-wave Mach-Zehnder modulators.

Interferometric method for phase calibration in liquid crystal spatial light modulators using a self-generated diffraction-grating.

Abstract: An auto-referenced interferometric method for calibrating phase modulation of parallel-aligned liquid crystal (PAL) spatial light modulators (SLM) is described. The method is experimentally straightforward, robust, and requires solely of a collimated beam, with no need of additional optics. This method uses the SLM itself to create a tilted plane wave and a reference wave which mutually interfere. These waves are codified by means of a binary diffraction grating and a uniformly distributed gray level area (piston) into the SLM surface. Phase shift for each gray level addressed to the piston section can then be evaluated. Phase modulation on the SLM can also be retrieved with the proposed method over spatially resolved portions of the surface. Phase information obtained with this novel method is compared to other well established calibration procedures, requiring extra elements and more elaborated optical set-ups. The results show a good agreement with previous methods. The advantages of the new method include high mechanical stability, faster performance, and a significantly easier practical implementation.

Minimizing dc drift in LiNbO3 waveguide devices

Abstract: Improved stability against electrical dc bias drift has been demonstrated in LiNbO3 electro‐optic modulators by replacing the commonly used SiO2 buffer layer with indium tin oxide (ITO), a transparent conductor. The long term drift of the modulators having an ITO buffer layer with a sheet resistivity of ∼20 Ω/⧠ is less than 0.3% in 8 h. The mechanism of the dc drift phenomenon is discussed using an electrical equivalent circuit model of the modulator.

Optical modulator and plane display element

Abstract: PROBLEM TO BE SOLVED: To provide an optical modulator and a plane display element in which a movable part is simply composed, a low voltage driving and a high speed response are possible. SOLUTION: In the optical modulator 21 which performs an optical modulation with an optical interference caused between the movable part 25 and a substrate part 23 by a dislocating action of the movable part 25 by an electrostatic force and an elastic returning action of the movable part 25, the movable part 25 is composed of a movable mirror layer 37 and a movable transparent electrode 39. The movable mirror layer 37 of the optical modulator 21 can be composed of a dielectric multilayer film, and in this case, a TiO 2 layer and a SiO 2 layer are used as the dielectric multilayer. Further, the optical modulator 21 may be composed in a way that the movable mirror layer 37 which is the dielectric multilayer functions as a transparent electrode. In this case, the dielectric multilayer may be composed of an indium tin oxide (ITO) layer and the SiO 2 layer. COPYRIGHT: (C)2004,JPO&NCIPI