Abstract: A dispersion compensator comprising an angular dispersive element that varies the angle at which the light, emitted from the optical transmission element through which it is transmitted, is output depending on its wavelength; an optical element that condenses the light emitted from the angular dispersive element; an optical deflector that deflects the light emitted from the optical element; and a reflecting mirror that is disposed in proximity to the focal point position in the optical system and that has a reflecting surface whose shape along the direction perpendicular to the plane on which the light is deflected changes at least in the direction along the plane on which the light is deflected.

Abstract: The accessing apparatus, which is to be used for an optical information recording and reproducing apparatus, controls the speed of a light spot and accesses the light spot to an object track. The apparatus includes a speed instructing device for outputting a speed instructing signal instructing the moving speed of the light spot when accessing the light spot to the object track. A track error signal detecting device detects a track error signal showing a position difference between the light spot and the track. A speed detecting device detects a speed detecting signal showing the relative speed between the light spot and the track by using the track error signal. An operating device operates the speed error signal based on the speed instructing signal and speed detecting signal. A driving device moves the light spot for the track based on the speed error signal to access the light spot to the object track by controlling the speed of the light spot.