Patent ID: 6478433
Filing Date: 2002-11-12
Classification: G02B,H04B

Abstract:
An apparatus comprising:a virtually imaged phased array (VIPA) generator receiving an input light at a respective wavelength and producing a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light; and a reflecting surface reflecting the output light back to the VIPA generator, the reflecting surface having a cone or modified cone shape, the reflecting surface having different curvatures at different positions along a direction perpendicular to a plane which includes the traveling directions of collimated output light from the VIPA generator for input light at different wavelengths, curvature c(y) of the reflecting surface being as follows: c&af;(y)=K8&it;f4&it;y4+K&it;â€ƒ&it;Î˜2&it;f3&it;y3+K&it;â€ƒ&it;Î˜2-(f-a)2&it;f2&it;y2â€ƒwhere y=is a light focusing position on the reflecting surface, &THgr;=is an input angle of the input light to the VIPA generator in air, f=is a focal length of a lens or mirror focusing the output light traveling from the VIPA generator onto the reflecting surface, a=is a depth of a center beam waist of the VIPA generator, and K=is a constant so that chromatic dispersion equals âˆ’2n4K/c&lgr;, with c being the speed of light, &lgr; being wavelength, and n being a refractive index of material forming the VIPA generator.