fiber Bragg grating

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fiber Bragg grating

A short length of optical fiber that filters out a particular wavelength. Periodically spaced zones in the fiber core are altered to have different refractive indexes slightly higher than the core. This structure selectively reflects a very narrow range of wavelengths while transmitting others. Fiber Bragg gratings are used to stabilize the output of a laser and to filter out wavelengths in a WDM system.

The name comes from Bragg's Law, which is used to create the spacing of the changes. Sir William Lawrence Bragg, noted British physicist (1890-1971) discovered this in his study of x-rays and crystal structures. See diffraction grating and WDM.

A Fiber Bragg Grating
Fiber Bragg gratings such as this one from JDS Uniphase can be customized for a variety of applications covering a range of wavelength bands from 850 to 1650 nm. (Image courtesy of JDS Uniphase.)

The Gratings Reflect
In this example, the red wavelength matches the grating period and is reflected. The blue wavelength is transmitted because it does not match the grating spacings. (Illustration assistance courtesy of Jeff Hecht.)

Optical Circulators
Since the desired wavelength is reflected back by the grating, another device known as an "optical circulator" detects and switches it. (Illustration courtesy of Jeff Hecht.)
References in periodicals archive ?
The fiber Bragg grating FBGti_1 corresponds to the complementary code sequence [C.
As the existing methods do not provide the complete solution, in this paper, we propose a new scheme by exploiting the linear properties, namely, reflection and transmission spectra of fiber Bragg gratings (FBGs).
Surface plasmon bragg gratings formed in metal-insulator-metal waveguides," Photonics Technology Letters, Vol.
A fiber Bragg grating, in its simplest form, is a length of fiber whose index of refraction is periodic in the direction of light propagation.
The boundary conditions for a Bragg grating of length L are R(L/2) = 1 and S(L/2) = 0, and then the mode fields for R and S integrate backward from z = L/2 to -L/2, thus obtaining R (-L/2) and (-L/2).
Optical System Development for Fiber Bragg Grating Writing
The European Business Awards is widely acknowledged as the showcase for Europe's most dynamic companies and we credit Proximion's worldwide leadership in developing optical modules and subsystems based on proprietary Fiber Bragg Grating (FBG) technology for this recognition.
Based on an optical silicon chip with an integral planar Bragg grating, it uses a fibre-optic cable to transmit a conditioned beam of light to the chip.
The test setup consisted of the bearing built into a gear test stand and equipped with an array of fibre Bragg grating sensors (Fig.
A NIST scientist designed, characterized, and recently delivered a calibration instrument for optical fiber Bragg grating (FBG) strain and temperature sensors to the Naval Research Laboratory (NRL).