POLARIZATION NOISE REDUCING ELEMENT

• Main Authors: HORIGUCHI TSUNEO, SUZUKI KAZUNOBU, AOMI YOSHIYUKI
• Format: Patent
• Language: English
• Published: 12.07.1986
• Subjects: COLORIMETRY; MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT,POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED,VISIBLE OR ULTRA-VIOLET LIGHT; MEASURING; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; RADIATION PYROMETRY; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR

PURPOSE:To reduce polarization noise while holding the merit of a polarized wave separation type optical directional coupler and to measure backscattered light or Fresnel reflected light from an optical fiber highly accurately by using the characteristics of double-refractive media. CONSTITUTION:N (N>=2) double-refractive media are arranged in series and the angle theta formed by the main axes of at least one group or more of adjacent double-refractive media is set up to an angle approximately satisfied with tan (2theta)=2. An optical pulse projected from a light source 1 is passed through a polarized wave separation type optical direction coupler 3, made incident upon a polarization holding optical fiber 4, and then made incident upon a testing SMF5. The light scattered backward or reflected in the testing SMF5 is passed through the fiber 4 again and only the polarized component rectangular to a polarizing direction of the incident optical pulse is guided to a photodetector 6 by the coupler 3 and detected. The fiber 4 concerned has double refractive property larger than that of a normal SMF, and when the polarization direction coincides with the main axis, the optical fiber propagates the incident light while holding the polarization direction of the incident light.