Patent ID: 7440656
Filing Date: 2008-10-21
Classification: G02B,H04J

Abstract:
1. An optical pulse time spreader comprising phase control means for time-spreading an optical pulse to be a string of chip pulses sequentially arrayed on a time base by encoding using an optical phase code and generating and outputting said chip pulse string, wherein said phase control means comprises unit diffraction gratings, which correspond to code values constituting said optical phase code one-to-one, arrayed in a row from a first to J-th unit diffraction grating (J is 3 or higher integer) sequentially from an input end of an optical wave guide along a wave guiding direction of said optical wave guide, chip pulses sequentially output from said phase control means are first to J-th chip pulses, said first chip pulse is a chip pulse which is generated and output by a single Bragg reflection at said first unit diffraction grating, said second chip pulse is a chip pulse which is generated and output by a single Bragg reflection at said second unit diffraction grating, a k-th chip pulse, where k is an integer that satisfies 3≦k≦J, is a chip pulse generated as a result of interference between a single reflection chip pulse which is generated and output by a single Bragg reflection at the k-th unit diffraction grating and an odd count reflection chip pulse which is generated and output by a triple or higher odd count of Bragg reflection based on a plurality of said unit diffraction gratings, reflectance of each of said unit diffraction gratings is set so that all the intensities of said first to J-th chip pulses are equalized, wherein reflectance R reflectance R reflectance R where P