Patent ID: 6900940

Claim:
An apparatus comprising: a virtually imaged phased array (VIPA) receiving a light, having a plurality of transmitting areas that output the light, dispersing the light having each wavelength within a continuous wavelength range at a different output angle and forming an output light spatially distinguishable from an output light formed for an input light having another wavelength within the continuous wavelength range; a lens focusing the output light having different output angles for each wavelength to different positions for each wavelength; a mirror reflecting back the focused light to the lens, the lens returning the reflected output light to VIPA, thereby the reflected light being multiple-reflected in the VIPA and output through the transmitting area from VIPA and the mirror having a shape such that the output light from VIPA receives an approximately constant wavelength dispersion regardless of the wavelength; and a filter having a desired asymmetrical periodic characteristic by passing a diverging or converging light having an angular distribution through an etalon, whereby the apparatus achieves a desired transmitting wavelength characteristic.