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.

A new general integral theory for dielectric coated gratings

Abstract: We present a new rigorous integral formalism for the theoretical study of dielectric coated gratings and grating couplers. It applies in the resonance domain, where the wavelength of the incident field and the groove spacing are of the same order of magnitude. The computed program issued from this theory extends the domain of application of the previous differential or integral theories. It can be used to investigate, with a very good accuracy, the properties of bare or dielectric coated gratings, for any groove shape and any polarization, in the entire visible, ultraviolet, and infrared regions. Various classical criteria are used to control the validity of the numerical results and comparisons are made with the numerical results obtained using the previous integral and differential formalisms. Two examples of applications are given. First, we show that the new possibilities of our program lead to a better agreement between theoretical results and experimental data. Second, a theoretical study of a certain type of grating coupler is given.

An intelligible explanation of highly-efficient diffraction in deep dielectric rectangular transmission gratings.

Abstract: This paper describes in a very easy and intelligible way, how the diffraction efficiencies of binary dielectric transmission gratings depend on the geometrical groove parameters and how a high efficiency can be obtained. The phenomenological explanation is based on the modal method. The mechanism of excitation of modes by the incident wave, their propagation constants and how they couple into the diffraction orders helps to understand the diffraction process of such gratings and enables a grating design without complicated numerical calculations.

Dual-wavelength erbium-doped fiber laser with a simple linear cavity and its application in microwave generation

Abstract: A single-longitudinal-mode (SLM) dual-wavelength erbium-doped fiber (EDF) laser based on a simple linear cavity is proposed and demonstrated. The SLM operation is achieved by incorporating a dual-phase-shift fiber grating with two ultranarrow transmission bands. Due to the gain grating produced by spatial hole-burning in the EDF, the proposed linear cavity supports dual-wavelength oscillation at room temperature with a wavelength interval of 27 pm. The laser output is heterodyned on a photodetector and the generated microwave signal has a linewidth <20 kHz without any feedback.

Planar waveguide echelle gratings in silica-on-silicon

Abstract: Silica planar waveguide echelle grating demultiplexers with 48 channels and 256 channels are described and demonstrated. Polarization effects due to stress birefringence and polarization-dependent grating efficiency have been eliminated using a modified polarization compensator and grating design. The devices have a polarization-dependent wavelength shift of less than 10 pm, and a polarization-dependent loss below 0.2 dB. The 48-channel device has a measured crosstalk of -35 dB, an insertion loss better than 4 dB, and a uniformity of 1 dB across the C-band.

Particle swarm optimization and its application to the design of diffraction grating filters

Abstract: Particle swarm optimization (PSO) is an evolutionary, easy-to-implement technique to design optical diffraction gratings. Design of reflection and transmission guided-mode resonance (GMR) grating filters using PSO is reported. The spectra of the designed filters are in good agreement with the design targets in a reasonable computation time. Also, filters are designed with a genetic algorithm (GA) and the results obtained by the GA and PSO are compared.