Sumitomo Osaka Cement Co., Ltd.

Masahito Mure

Norikazu Miyazaki

Toshio Kataoka

Tokutaka Hara

Kaoru Higuma

Miki Yatsuki

Junichiro Ichikawa

Takeshi Sakai

Yoichi Oikawa

Hiroshi Nagaeda

Noriyasu Shiga

Hitoshi Oguri

Masaaki Sudo

Masahide Miyachi

Hiroyuki Sato

It is possible to suppress carrier light with a simple configuration when modulating the carrier light to generate optical sideband components. An optical carrier-suppressed signal generator includes first splitting means used to split input carrier light into two light beams, an optical modulator which modulates one split carrier light beam and outputs light including optical sideband components, a phase modulator which phase-modulates another split carrier light beam, and second or third splitting means used to split the output light of the optical modulator into two light beams. The output light split by the second or third splitting means and the output light of the phase modulator are multiplexed to obtain the amplitude of the signal waveform of optical power, and the optical modulator is controlled such that the obtained value is minimized.

Optical carrier-suppressed signal 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

Provided is an optical receiver which accurately demodulates an optical signal obtained by the differential phase shift modulation method. The optical receiver includes: an interferometer which branches the inputted optical signal into two parts and gives a one-bit phase difference to the resultant two optical signals so that the two optical signals after addition of the phase difference are made to interfere each other to output two output lights; reflection means which reflects one of the output lights from the interferometer so as to return to the interferometer; detection means which detects the return light which has been reflected by the reflection means and propagates through the interferometer in the different direction from the inputted optical signal, for output; and phase difference control means which adjusts the phase difference given by the interferometer according to the intensity of the return light detected by the detection means.

Optical receiver

The present invention relates to an optical receiver, and particularly, to an optical receiver by which a DQPSK-modulated optical signal is demodulated to a multilevel phase-modulated signal.

An external cavity semiconductor laser including a first and second input-output section disposed on a common end surface via a center axis, and a semiconductor laser device emitting a first and second laser light from the first and second input-output sections in two directions. The laser device includes a first reflecting unit for reflecting the first laser light emitted from the first input-output section and returning the reflected first laser light to the first input-output section, a second reflecting unit for reflecting the second laser light emitted from the second input-output section and returning the reflected second laser light to the second input-output section, a third reflecting unit provided to a second end surface disposed opposite a first end surface having first and second input-output sections for reflecting laser light returned to one of the input-output sections so as to be emitted from the other one of the input-output sections.

External cavity semiconductor laser

A laser beam generating apparatus includes a semiconductor element and a second harmonic generating element that performs a wavelength conversion on fundamental light emitted from the semiconductor element, the laser beam generating apparatus is an external resonance-type laser diode that has an external resonator structure and emits a transversal single mode laser beam, and the second harmonic generating element is a waveguide-type second harmonic generating element that includes a single mode waveguide.

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Chiyoda-ku, Japan

Masahito Mure