Other

Kazumasa Takada

Tohru Mori

Tetsuo Yano

Shoichi Aoki

Fumio Akikuni

Masaharu Horiguchi

Kenji Senda

Syoichi Aoki

A photocoupler splits the light from a low-coherence light source into measuring light DL and local oscillator light KL. A photocoupler receives measuring light DL arid is input to an optical circuit to be measured. The photocoupler splits the reflected light RL. A polarization controller controls the state of polarization of the reflected light RL as split by the photocoupler . A photocoupler allows local oscillator light KL to be incident on a reflector mirror and splits local oscillator light KL. A photocoupler combines the reflected light RL as controlled in the state of polarization by the polarization controller , with the local oscillator light KL.

Low-coherence reflectometer with polarization control

A low coherent reflectometer uses low coherent beams for measurement of refletance and refleting positions with respect to a measured optical circuit which includes a reflecting point. The low coherent beams are branched to produce measurement beams (DL) and local beams (KL), so that the measurement beams are introduced into a first optical path, which includes a dispersion shifted fiber, towards the measured optical circuit, while the local beams are introduced into a second optical path which includes a spatial optical path terminated by a reflecting mirror. Refleted measurement beams (RL) and reflected local beams are combined together to produce combined beams, which are subjected to processing and analysis.

Low coherent reflectometer

Emitted light from a light source is separated into two parts through an optical fiber coupler , one is entered in a measured optical module as measurement light, and the other is given a group delay by means of an optical fiber delay line , a reflector , etc., as local light signal, then the local light signal is combined with reflected light signal from the measured optical module through an optical fiber coupler and the reflected light signal and the local light signal are caused to interfere with each other. A polarization controller comprising a polarizer and a polarization rotation device for arbitrarily rotating the polarization state 0 degrees and 90 degrees at the time is used to generate beat signals at the polarization rotation angles, and the sum of the intensities of the beat signals is found, making it possible to measure the light power of the reflected light signal regardless of the polarization state of the local light signal or reflected light signal.

Polarization-independent reflectometry and polarization-independent reflectometer

Growing community of inventors

Tokyo, Japan

Kazumasa Takada