Patent ID: 8922760

Claim:
A defocused optical rotation measurement apparatus for measuring for optical information on optical rotation characteristics of a specimen by deploying single mode first and second optical fibers, each having a lens deployed at a tip end, along an optical path of an optical signal, facing each other and sandwiching the specimen for optical rotation measurement irradiating on the specimen an optical signal emitted from an end of the first single mode optical fiber having the lens at the tip end, and also irradiating on the specimen an optical signal emitted from an end of the second single mode optical fiber having the lens at the tip end, irradiating an optical signal having passed through the specimen and an optical signal reflected by the specimen on an end of the first single mode optical fiber having the lens at the tip end; wherein in a state of measuring optical rotation of the specimen, the lens deployed at an output part of the first single mode optical fiber for an optical signal irradiated on the specimen and/or an inlet part for an optical signal from the specimen, and the output part lens deployed at an inlet part of the second single mode optical fiber for an optical signal from the specimen and/or an output part for an optical signal irradiated on the specimen are deployed along the optical path of the optical signal, and at least either an end of the first single mode optical fiber or an end of the second single mode optical fiber forms a defocused optical fiber optical system not deployed at a focal point of the output part lens of said first and second single mode optical fibers; wherein the first single mode optical fiber and the second single mode optical fiber are polarization preserving fibers; a polarizer, a Faraday rotary element, and a ¼ wave plate are arranged between each of the optical fiber ends and the specimen; an optical signal of the same natural polarization mode is emitted from both of the polarization preserving fibers, a clockwise propagating light or a counterclockwise propagating light entering from one of the inlet sides of the specimen, and counterclockwise propagating light or a clockwise propagating light entering from the other one of the inlet sides of the specimen are mutually orthogonal at the position of the specimen, and directions of the polarizer, the Faraday rotary element, and the ¼ wave plate and a natural polarization direction of the polarization preserving fibers are set such that the lights are coupled with the polarization preserving fibers on an optical path in a polarization mode equivalent to the polarization output mode.