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.

Semiconducting polymer distributed feedback lasers

Abstract: We have fabricated photopumped distributed feedback lasers by spin-casting thin films of the semiconducting polymer poly(2-butyl, 5-(2′-ethyl-hexyl)-1,4-phenylenevinylene) over gratings in silicon oxide. The lasers have two modes that each have a linewidth of 0.2 nm. The lasing wavelength was tuned from 540 to 583 nm by adjusting the period of the gratings.

Apodized Waveguide Grating Couplers for Efficient Coupling to Optical Fibers

Abstract: We describe a shallow-etched diffractive waveguide grating coupler which achieves efficient coupling between single-mode fiber and a silicon-on-insulator optical waveguide. By the appropriate choice of waveguide/grating thicknesses and varying the coupling strength of the grating coupler via tailoring its fill factor to optimize the mode matching, a coupling loss of only 1.2 dB was obtained for each fiber/silicon waveguide interface. The coupling strength and effective refractive index of grating with different fill factors were also characterized to confirm the design simulations. The back reflection was suppressed by varying the coupling strength, leading to further enhancement of the coupling efficiency.

Fiber-optic Bragg grating strain sensor with drift-compensated high-resolution interferometric wavelength-shift detection

Abstract: The operation of a fiber Bragg grating strain sensor system that uses interferometric determination of strain-induced wavelength shifts and incorporates a reference channel to compensate for random thermal-induced drift in the output is described. This system is shown to be capable of resolving sub-microstrain changes in the quasi-static strain applied to a grating and has a resolution of ~6 x 10(-3) microstrain/ radicalHz at a strain perturbation frequency of 1 Hz.

Narrowband operation of a pulsed dye laser without intracavity beam expansion

Abstract: A new simple cavity design for nitrogen‐laser‐pumped dye lasers is presented. Narrowband operation is achieved with a single dispersive element and without any intracavity beam expansion. The dispersive element is a diffraction grating used near grazing incidence with an additional mirror, instead of the usual Littrow arrangement. The large angular dispersion obtained results in a linewidth of 0.08 cm−1. The typical peak power obtained is 4 kW with 50 kW in the pump beam. Calculations of linewidth based on single‐pass estimates are presented and are found to be in good agreement with experimental results.

Grating and prism compressors in the case of finite beam size

Abstract: The grating and prism compressors are studied for the case of finite beam size by using the Kirchhoff–Fresnel integral and an amplitude transfer operator for the grating and prism. The results show that, even for well-collimated beams, pulse broadening may occur (mainly because of the wavelength dependence of the lateral walk-off). Methods to avoid the different types of distortions appearing in these systems are discussed.