Patent ID: 6574396
Filing Date: 2003-06-03
Classification: G02B,H04J

Abstract:
An optical imaging apparatus comprising a grating having an input curve and an output image curve produced with specified magnification M, the optical imaging apparatus further comprisingan input waveguide connected to a location P of the input curve for receiving an input signal at a particular input wavelength, the input signal being dispersed by the various orders of the grating into a set of equally spaced images produced on the output image curve with spacing &OHgr;, the dispersion by the grating causing the locations of the output images on the output image curve to vary with wavelength and a periodic arrangement A of reflective elements located along the output image curve with period essentially equal to an integer fraction of the spacing &OHgr; of the output images, where the integer can be equal to unity, each reflective element essentially reversing the propagation direction of an image intercepted by that element, the periodic arrangement thereby causing the set of equally spaced images to produce reflected signals which pass back through the grating to the input waveguide, the reflected signals are efficiently transferred back to the input waveguide, thereby causing an output signal traveling in the input waveguide in a direction opposite that of the input signal.