Optical fiber sensor utilizing faraday rotator mirrors and measuring system using the same
The present invention is the optical fiber sensor, that laser pulses from a laser source are separated into a reference path and a measurement path by the second optical coupler via the first optical coupler, the first FRM is provided at an end of the reference path, the second FRM is provided at an end of the measurement path, and the reference reflected light of the first FRM and the measurement reflected light of the second FRM are interfered at the second optical coupler and are converted into three phases. The first phase pulses are transmitted to the optical synthesis section via the first optical coupler, second phase pulses are transmitted to the optical synthesis section via the first delay section, and third phase pulses are transmitted to the optical synthesis section via the second delay section. The time division pulse train is outputted from the optical synthesis section.
1 . An optical fiber sensor,
wherein laser pulses from a laser source are separated into two phases of a reference path and a measurement path including a measuring object, which form an interferometer, by a second optical coupler via a first optical coupler;
wherein a first Faraday Rotator Mirror (FRM) is provided at an end of said reference path, and a second FRM is provided at an end of said measurement path; and
wherein a reference reflected light of said first FRM and a measurement reflected light of said second FRM are interfered at said second optical coupler and are converted into three phases, converted first phase pulses are transmitted to an optical synthesis section via said first optical coupler, converted second phase pulses are transmitted to said optical synthesis section via a first delay section, converted third phase pulses are transmitted to said optical synthesis section via a second delay section, and a time division pulse train is outputted from said optical synthesis section.
2 . The optical fiber sensor according to claim 1 , wherein all transmissions of said laser pulses are performed by using a single mode (SM) fiber.
3 . The optical fiber sensor according to claim 1 , wherein a delay time of said second delay section is longer than a delay time of said first delay section.
4 . A measuring system to measure a displacement of said measuring object by measuring a peak value of said time division pulse train as claimed in claim 1 .
5 . An optical fiber sensor that measuring pulses are transmitted to “n(≥2)” interferometers respectively including a measuring object, and Time Division Multiplexing (TDM) pulse trains corresponding to respective displacements of said measuring objects from said “n” interferometers are optically synthesized and are outputted,
wherein “n−1” optical couplers to convert laser pulses into two phases of said measuring pulses and delaying pulses are provided;
wherein a first stage optical coupler inputs laser pulses from a laser source, and a second stage to (n−1)th stage optical couplers respectively input said delaying pulses from a previous stage via a delay section;
wherein n-th optical coupler transmits said delaying pulses from (n−1)th optical coupler to said n-th interferometer and inputs;
wherein respective TDM pulse trains outputted from said “n” interferometers are sequentially and optically synthesized, and a multiple TDM pulse train is outputted; and
wherein respective said “n” interferometers comprise a constitution that:
said laser pulses are separated into two phases of a reference path and a measurement path including a measuring object, which form an interferometer, by a second optical coupler via a first optical coupler;
a first Faraday Rotator Mirror (FRM) is provided at an end of said reference path and a second FRM is provided at an end of said measurement path; and
a reference reflected light of said first FRM and a measurement reflected light of said second FRM are interfered at said second optical coupler and are converted into three phases, converted first phase pulses are transmitted to an optical synthesis section via said first optical coupler, converted second phase pulses are transmitted to said optical synthesis section via a first delay section, converted third phase pulses are transmitted to said optical synthesis section via a second delay section, and a time division pulse train is outputted from said optical synthesis section.