Optical modulator

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

Broadband Optical Modulators Based on Graphene Supercapacitors

Abstract: Optical modulators are commonly used in communication and information technology to control intensity, phase, or polarization of light. Electro-optic, electroabsorption, and acousto-optic modulators based on semiconductors and compound semiconductors have been used to control the intensity of light. Because of gate tunable optical properties, graphene introduces new potentials for optical modulators. The operation wavelength of graphene-based modulators, however, is limited to infrared wavelengths due to inefficient gating schemes. Here, we report a broadband optical modulator based on graphene supercapacitors formed by graphene electrodes and electrolyte medium. The transparent supercapacitor structure allows us to modulate optical transmission over a broad range of wavelengths from 450 nm to 2 μm under ambient conditions. We also provide various device geometries including multilayer graphene electrodes and reflection type device geometries that provide modulation of 35%. The graphene supercapacitor str...

Wavefront correction of spatial light modulators using an optical vortex image

Abstract: We present a fast and flexible non-interferometric method for the correction of small surface deviations on spatial light modulators, based on the Gerchberg-Saxton algorithm. The surface distortion information is extracted from the shape of a single optical vortex, which is created by the light modulator. The method can be implemented in optical tweezers systems for an optimization of trapping fields, or in an imaging system for an optimization of the point-spread-function of the entire image path.

Dynamics of microring resonator modulators.

Abstract: A dynamic model for the transmission of a microring modulator based on changes in the refractive index, loss, or waveguide-ring coupling strength is derived to investigate the limitations to the intensity modulation bandwidth. Modulation bandwidths approaching the free spectral range frequency are possible if the waveguide-ring coupling strength is varied, rather than the refractive index or loss of the ring. The results illustrate that via controlled coupling, resonant modulators with high quality factors can be designed to operate at frequencies much larger than the resonator linewidth.

Microelectrical mechanical structure (MEMS) optical modulator and optical display system

Abstract: A MEMS optical display system includes an illumination source for providing illumination light, a collimating lens for receiving the illumination light and forming from it collimated illumination light, and a converging microlens array having an array of lenslets that converge the collimated illumination light. The converging microlens array directs the illumination light to a microelectrical mechanical system (MEMS) optical modulator. The MEMS optical modulator includes, for example, a planar substrate through which multiple pixel apertures extend and multiple MEMS actuators that support and selectively position MEMS shutters over the apertures. A MEMS actuator and MEMS shutter, together with a corresponding aperture, correspond to pixel. The light from the converging microlens array is focused through the apertures and is selectively modulated according to the positioning of the MEMS shutters by the MEMS actuators, thereby to impart image information on the illumination light. The light is then passed to a diffused transmissive display screen by a projection microlens array.

Beam Shaping with Optical Array Generators

Abstract: An array generator is an optical system that splits an incoming beam of light into an array of many ‘beamlets’. Such a multiple beam-splitting system is necessary in optical data processing, where two-dimensional arrays of optical modulators, optical logic devices or optically bistable devices have to be read out optically or have to be provided with power-supply or bias beams. Other applications include multiple imaging and space-variant processing. The number of beams within an array has to be adapted to the size of the array of optical devices, also the modal shape of each single beam has to be adapted to the acceptable modes for the individual devices. Different systems for array generation are classified and compared with respect to their relevant parameters. Methods for modal adaptation are described. The influence of coherent noise and of chromatic errors is investigated. Non-Cartesian and irregular array generators are proposed.