Optical apparatus which uses a virtually imaged phased array to produce chromatic dispersion

DETAILED DESCRIPTION Therefore, it is an object of the present invention to provide an apparatus which produces chromatic dispersion, and which is practical for compensating for chromatic dispersion accumulated in an optical fiber.
Objects of the present invention are achieved by providing an apparatus which includes a device herein referred to as a "virtually imaged phased array", "VIPA" or "VIPA generator".
The VIPA generator produces a light propagating away from the VIPA generator.
The apparatus also includes a mirror or reflecting surface which returns the light back to the VIPA generator to undergo multiple reflection inside the VIPA generator.
Objects of the present invention are achieved by providing an apparatus comprising a VIPA generator and a reflecting surface.
The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light.
The reflecting surface reflects the output light back to the VIPA generator.
The reflecting surface has different curvatures at different positions along a direction perpendicular to an angular dispersion direction of the VIPA generator, or a plane which includes the traveling directions of collimated output light from the VIPA generator for input light at different wavelengths.
Objects of the present invention are also achieved by providing an apparatus which includes a VIPA generator, a reflecting surface, and a lens.
The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength.
The reflecting surface has a cone shape, or a modified cone shape.
The lens focuses the output light traveling from the VIPA generator onto the reflecting surface so that the reflecting surface reflects the output light, the reflected light being directed by the lens back to the VIPA generator