# US 7,746,475 B2 · Microgyroscope

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- Number: US 7,746,475 B2
- Document ID: US7746475B2
- Status: Granted
- Kind: B2
- Application number: 12/245,970
- Filed: 2008-10-06
- Published: 2009-04-09
- Granted: 2010-06-29
- Earliest claimed: 2007-10-09
- Assignees: Samsung Electronics Co., Ltd.; Seoul National University Industry Foundation
- Inventors: Q Han Park; Heon Su Jeon
- Web page: https://patentgrep.com/patent/US7746475B2

## CPC

- G01C 19/72: with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
- H01S 3/0604: {in the form of a plate or disc}
- H01S 3/0627: {the resonator being monolithic, e.g. microlaser}
- H01S 3/083: Ring lasers {(fibre ring lasers H01S3/06791)}
- H01S 3/094057: {by tapered duct or homogenized light pipe, e.g. for concentrating pump light}
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

A new high-performance, compact microgyroscope is implemented using a microlaser such as a microsphere laser or a microdisc laser that can be easily reduced in size. The microgyroscope includes a pumping unit for inputting pumping light for optical pumping, at least one microsphere or microdisc for oscillating a laser beam by performing optical pumping using light received from the pumping unit, an output coupler for receiving the oscillated laser beam from the microsphere or microdisc, and a photodetector for calculating a beat frequency due to interference between beams output from the output coupler to measure rotation. The pumping unit and the output coupler are constructed using a tapered optical fiber.

## Claims

### Claim 1

A microgyroscope, comprising:
a tapered optical fiber defining a pumping unit and an output coupler, the pumping unit inputting pumping light for optical pumping;
first and second microspheres or microdiscs disposed on first and second sides, respectively, of the tapered optical fiber, the first and second microspheres or microdiscs oscillating first and second laser beams, respectively, therein by performing optical pumping using the pumping light received from the pumping unit;
the output coupler receiving the oscillated laser beam from the first and second microspheres or microdiscs; and
a photodetector receiving the first and second laser beams and a processor that receives an output from the photodetector and calculates a beat frequency due to interference between the first and second laser beams output from the output coupler to measure rotation.

### Claim 2 (depends on 1)

The microgyroscope according to claim 1, wherein the tapered optical fiber has a hybrid fiber taper coupling structure with different Single Mode Fiber modes in which an input optical fiber and an output optical fiber for the microsphere or microdisc are joined to create a taper structure.

### Claim 3 (depends on 1)

The microgyroscope according to claim 1, further comprising multiple pairs of microspheres or microdiscs, and the multiple pairs of microspheres or microdiscs are connected in an array form to both sides of the tapered optical fiber.

### Claim 4 (depends on 3)

The microgyroscope according to claim 3, further comprising a pump filter for filtering out the pumping light located near an end of the output coupler.

### Claim 5

A microgyroscope, comprising:
a pumping unit inputting pumping light;
a single microsphere or microdisc oscillating first and second laser beams therein by performing optical pumping using the pumping light received from the pumping unit;
an output coupler having first and second tapered optical fibers connected to first and second sides, respectively, of the single microsphere or microdisc, and a Y juncture coupled to the first and second tapered optical fibers to combine the first and second laser beams therein; and
a photodetector receiving the first and second laser beams from the Y juncture and a processor that receives a beat frequency due to interference between the first and second laser beams to measure rotation.

### Claim 6 (depends on 5)

The microgyroscope according to claim 5, wherein the pumping unit and the single microsphere or microdisc are constructed using a single optical fiber, and the single microsphere or microdisc is formed by fusing an end of another optical fiber using another laser beam.