Nippon Telegraph and Telephone Corporation

Ando Electric Company

Neubrex Co., Ltd.

Yahei Koyamada

Haruyoshi Uchiyama

Tsuneo Horiguchi

Kaoru Shimizu

Nobunari Takeuchi

Tekken Lee

Kinzo Kishida

Kenichi Nishiguchi

In a measurement requiring a high space resolution using S-BOTDR, a pulse train composed of a plurality of pulses having the interval between the pulses longer than the phonon lifetime is interpulse-code-modulated. A Golay code is used for the interpulse code modulation to eliminate the sidelobes of the correlation in using a technique of correlation. In a technique without using correlation, an Hadamard matrix is used for the interpulse code modulation and the resultant matrix is inverted in the signal processing.

Brillouin scattering measurement method and Brillouin scattering measurement device

The present invention provides light frequency control apparatus comprising a light pulse signal generating mechanism for generating a light pulse signal of a standard frequency; a light frequency shifting mechanism for circulating this light pulse signal a predetermined number of times, delaying this light pulse signal at each cycle thereby sequentially shifting and outputting the aforementioned light pulse signal; an extracting mechanism for extracting a light pulse signal in the second half of a cycle from the output of the light frequency shifting mechanism; and a polarization control mechanism inserted into the light frequency shifting mechanism for controlling the angle of polarization of the light pulse signal circulating in the light frequency shifting mechanism based on the amount of attenuation of the light pulse signal outputted by the extracting mechanism.

Light frequency control apparatus

The present invention provides light frequency control apparatus comprising a light pulse signal generating mechanism for converting continuous light into a light pulse signal, and outputting this light pulse signal; a light signal generating mechanism for repeatedly generating at predetermined cycles, a light signal, in which a light frequency component therein is shifted to form a staircase shape based on the number of cycles of a loop within which the light pulse signal circulates; and a dummy light generating mechanism for generating dummy light at a timing such that the level of the light signal becomes zero, and supplying this dummy light to the light amplifying mechanism. The aforementioned loop is formed from a light amplifying mechanism for amplifying the light pulse signal outputted from the light pulse signal generating mechanism, light delay mechanism for delaying the light pulse signal a fixed amount; and frequency shifting mechanism for shifting the frequency of the light pulse signal.

Growing community of inventors

Tokyo, Japan

Yahei Koyamada