Document Type : Research
Author
Scientific member
Abstract
Optical spectrometers generally, and specially the compact and miniaturized ones with small dimensions, versatile and resistant due to harsh environments conditions, are highly interested. These apparatuses have wide applications in all scientific and industrial applications in measurement, sensing, material analysis and optical communication devices. In a novel design for this kind of spectrometers, elimination of the focusing element (lenses) can be established by inscription a chirped Bragg grating directly on a usual optical fiber, promotes further size reduction and increases device toleration against harsh environmental condition.
In the present paper, a wave-optics based, diffraction superimposition method is employed for design of appropriate Bragg grating for this structure, then it compared with the results of usual FDTD simulation. The outcome reveals the good agreement respect to FDTD, as well as, extraordinary higher speed in calculation, especially in higher physical sizes. Linear dispersion of spectrum on the one-dimensional array of optical detector and the resolution parameters are calculated by utilizing profits of diffraction method. Also using the curved detectors array instead of plane array is proposed in order to improve wavelength resolving power in miniaturized spectrometer. This design showing acceptable accuracy of 2nm for resolution with resolving power of 250 in whole near-IR, visible and near-UV wavelength domain, has more advantages respect to other miniature spectrometers.
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