APPARATUS AND METHOD FOR MEASURING OPTICAL WAVEGUIDE

• Main Authors: KO BIBI, INAGAKI KEIZO
• Format: Patent
• Language: English
• Published: 26.06.2002
• Edition: 7
• Subjects: COLORIMETRY; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT,POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED,VISIBLE OR ULTRA-VIOLET LIGHT; MEASURING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; RADIATION PYROMETRY; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR

PROBLEM TO BE SOLVED: To measure the double refraction of an optical waveguide more easily and accurately than in conventional cases. SOLUTION: An MZ modulator 4 modulates an optical signal of a linearly polarized wave according to an input reference microwave signal and outputs the modulated optical signal via an optical-fiber cable 7 to the optical waveguide 8 to be measured, and a photoelectric converter 13 performs photoelectric conversion on the optical signal output from the optical waveguide 8 and outputs the result. An automatic alignment mechanism 9 rotates the output end of the optical-fiber cable 7 so that the plane of polarization of the modulated optical signal incident on the input end of the optical waveguide 8, before rotation about the optical axis of the optical waveguide 8, is perpendicular to the plane of polarization of the signal after the rotation. A network analyzer 15 measures a first phase difference between the converted microwave signal before the rotation and the reference microwave signal and a second phase difference between the converted microwave signal after the rotation and the reference microwave signal. A measurement controller 20 computes the double refraction of the optical waveguide on the basis of the first and second phase differences.