Sumitomo Osaka Cement Co., Ltd.

National Institute of Information and Communications Technology, Incorporated

Masaaki Sudo

Junichiro Ichikawa

Tetsuya Kawanishi

Tokutaka Hara

Masahito Mure

Akito Chiba

Provided is an optical pulse-generator capable of efficiently using by a low driving voltage an entire band of an optical frequency comb input to a chirp compensator for the formation of an optical pulse. According to a graph shown in FIG., dispersion compensation amounts (dispersion characteristics) necessary for a chirp (dispersion) compensator to efficiently compress an optical frequency comb which sinusoidally changes become an inverse of a parabolic coefficient. It is found that the dispersion compensation amount required at the center frequency is 2/&#x3c0; of that of a chirp being approximate to a linear chirp, and the required dispersion compensation amount increases as the frequency shift increases.

Optical pulse-generator

The optical frequency comb generating device having two optical modulation partsandindependently modulating optical waves propagating in two branch waveguides and a phase regulatorcontrolling a phase difference between the optical waves includes amplitude adjusting meansfor adjusting a voltage amplitude of the RF signal supplied to at least one of the optical modulation parts, monitoring meansfor monitoring the intensity Pof the output light beam, and a bias control circuitthat controls the amplitude adjusting means to change a difference in voltage amplitude between the RF signals supplied to each optical modulation part, that detects a variation of the output light beam corresponding to the variation of the difference in voltage amplitude from the output signal of the monitoring means, and that controls the phase regulator on the basis of the detection result to adjust the phase difference.

Optical frequency comb generating device and optical pulse generating device using same, and optical frequency comb generating method and optical pulse generating method using same

A method for evaluating a characteristic of, especially, each of Mach-Zehnder interferometers (MZIs) of an optical modulator. The method includes a step of measuring the intensity of the output of the optical modulator containing MZIs and a step of evaluating a characteristic of each MZI by using the sideband. The output intensity measuring step is the one of measuring the intensity Sof the sideband signal contained in the output light from the optical modulator. The characteristic evaluating step is the one of evaluating a characteristic of the MZIby using the S.

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Tokyo, Japan

Masaaki Sudo