Diffraction grating

About: Diffraction grating is a research topic. Over the lifetime, 24884 publications have been published within this topic receiving 372437 citations. The topic is also known as: grating.

Integrated bi-directional axial gradient refractive index/diffraction grating wavelength division multiplexer

Abstract: A wavelength division multiplexer that integrates an axial gradient refractive index element with a diffraction grating to provide coupling from a plurality of input optical sources (each delivering a single wavelength) which are multiplexed to a single polychromatic beam for output to a single output optical receiver. The device comprises means for accepting optical input from at least one optical source, the means including a planar surface (20a); a coupler element (20) comprising an axial gradient refractive index collimating lens (26) having a planar entrance surface onto which the optical input is incident and a homogeneous index boot lens (24, 28) affixed to the axial gradient refractive index collimating lens and having a planar but tilted exit surface (20b); a diffraction grating (22) on the tilted surface of the homogeneous index boot lens which combines a plurality of spatially separated wavelengths from the optical light; and means to output at least one multiplexed, polychromatic output beam, the means including a planar surface (20a). The device may be operated in the forward or reverse direction as a multiplexer or demultiplexer.

Generation of pure two-beam interference grating structures in an optical fiber with a femtosecond infrared source and a phase mask.

Abstract: Fiber Bragg gratings were fabricated in all-silica core fiber by focusing 125-fs 800-nm pulses with an 80-mm lens through a phase mask with 4.28‐µm pitch onto a fiber sample. When the phase-mask–fiber separation was 5 mm the observed structure was clearly the result of two-beam interference between the ±1 orders. The elimination of the remaining 9 orders is a consequence of the walk-off experienced by the mask orders and the short duration of the femtosecond pulse. This effect is unique to the fabrication of Bragg gratings with femtosecond sources and would not be observed with a longer pulse duration or incoherent UV sources.

Optical grating and method of manufacture

Abstract: A method and system for providing an optical grating are described. The optical grating is configured for light of a wavelength and includes a first optically transparent layer, a stop layer on the first optically transparent layer, and a second optically transparent layer on the stop layer. The first optically transparent layer is continuous and includes a material. The second optically transparent layer also includes the material. The second optically transparent layer also includes a plurality of discrete ridges spaced apart by a pitch. The stop layer is configured to be invisible to the light.

Novel interrogating system for fibre Bragg grating sensors using an acousto-optic tunable filter

Abstract: A new technique for the interrogation of in-fibre Bragg grating sensors using an acousto-optic tunable filter (AOTF) is demonstrated. The scheme involves frequency shift keying (FSK) of the RF drive to the AOTF to track the wavelength shifts of a Bragg grating. Experimental results are presented for temperature measurement. This technique provides a frequency-agile system, capable of rapid, random access and very wide tuning range.