OPTICAL PULSE GENERATING CIRCUIT AND SPECTRUM CHARACTERISTICS MEASURING INSTRUMENT

摘要

PURPOSE:To shorten a measurement time by cutting off an optical path of a wavelength component converged on a single focus by a waveguide. CONSTITUTION:A semiconductor laser 12 is driven by a driving circuit 11 including a modulating signal source and its light pulse output is made incident as a parallel beam on the optical circuit consisting of diffraction gratings 1 and 2, lenses 3 and 4, and a spatial distribution filter 5. The projection parallel beam light from this optical circuit is passed through an optical fiber 17 for optical compression and outputted as an output optical pulse. Consequently, the optical pulse outputted having nearly Lorentz waveform is diffracted by the diffraction grating and converged by the lens 3 and its focal plane goes to a Ferry plane of on optical frequency. This the filter 5 arranged in an optical frequency plane based upon said plane as position coordinates imposes modulation in a specific wavelength range. This modulated optical pulse is passed through the lens 4 and grating 2 to go to a parallel beam, which is passed through the fiber 17 for optical pulse compression and guided out as an output optical pulse having desired waveform.