Optical waveguide recording medium playing apparatus.

摘要

An optical system for reading and reproducing recorded information from an optical waveguide recording medium (1) is characterised in that an optical frequency modulating element (33) for modulating light emitted from a super luminescent diode (SLD) as a light source (35) is provided between the SLD and a beam splitter (36). The optical frequency modulating element (33) may comprise an ultrasonic light modulating element (33a) with a frequency-modulated drive voltage to diffract the light from the SLD (35) and a slit (33b) which limits the spatial spectrum of the diffracted light. As the voltage to drive the ultrasonic light modulating element is frequency-modulated, the pitch of an elastic wave formed in the ultrasonic light modulating element will be modulated. This varies the diffraction angle of the light of the same frequency, thus changing the frequency of light that passes through the slit. Alternatively, the optical frequency modulating element (33) may comprise an acoustooptic modulating element (33c) driven at a high frequency, and a movable slit (33d) to select the desired diffracted light.