# US 2014/0152982 A1 · Sensor and method of sensing

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- Number: US 2014/0152982 A1
- Document ID: US20140152982A1
- Status: Published application
- Kind: A1
- Application number: 14/233,168
- Filed: 2011-07-27
- Published: 2014-06-05
- Earliest claimed: 2011-07-27
- Assignees: Omnisens SA
- Inventors: Julien Gosteli; Fabien Ravet; Etienne Rochat
- Web page: https://patentgrep.com/patent/US20140152982A1

## CPC

- G01N 21/8806: {Specially adapted optical and illumination features}
- G01D 5/35364: {using inelastic backscattering to detect the measured quantity, e.g. using Brillouin or Raman backscattering}
- G01L 1/242: {the material being an optical fibre}
- G01M 11/085: {the optical fiber being on or near the surface of the DUT}
- G01M 11/319: {Reflectometers using stimulated back-scatter, e.g. Raman or fibre amplifiers}
- G01M 11/39: {in which light is projected from both sides of the fiber or waveguide end-face}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR

## Abstract

According to the invention, these aims are achieved by means of a sensor, suitable for sensing one or more properties of one or more structures, the sensor comprising, a first optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a second optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a third optical propagation path; a means for amplifying a signal which propagates in the third optical propagation path, so that the signal is amplified before it begins propagation along the second optical propagation path, and a means to prevent the propagation of signals from the second optical propagation path to the third optical propagation path. There is further provided a corresponding method of sensing.

## Claims

### Claim 1

A sensor, suitable for sensing one or more properties of one or more structures, the sensor comprising, a first optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a second optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; and
a third optical propagation path; a means for amplifying a signal which propagates in the third optical propagation path, so that the signal is amplified before it begins propagation along the second optical propagation path
a means to prevent the propagation of signals from the second optical propagation path to the third optical propagation path.

### Claim 2 (depends on 1)

A sensor according to claim 1 further comprising, a means to prevent the propagation of signals from the first optical propagation path to the second optical propagation path.

### Claim 3 (depends on 2)

A sensor according to claim 2 wherein the means is further configured to allow the propagation of signals, from the second optical propagation path to the first optical propagation path and from the third optical propagation path to the second optical propagation path.

### Claim 4 (depends on 1)

A sensor according to claim 1 wherein the means to prevent the propagation of signals from the second optical propagation path to the third optical propagation path comprises a circulator circuit.

### Claim 5 (depends on 1)

A sensor according to claim 1 wherein the third optical propagation path is configurable to be arranged remote to the one or more structures so that a signal propagating in the third optical propagation path is unaffected by properties of the one or more structures.

### Claim 6 (depends on 1)

A sensor according to claim 1 further comprising, a means for providing a first pump signal to the first optical propagation path, a means for providing a second pump signal to the third optical propagation path, and a means for providing a probe signal to the second optical propagation path, so that one or more distributed sensing techniques may be carried out to determine properties of the one or more structures.

### Claim 7 (depends on 6)

A sensor according to claim 6 wherein the first pump signal is configured to have a higher power than the second pump signal.

### Claim 8 (depends on 6)

A sensor according to claim 6 wherein, the means for providing a first pump signal to the first optical propagation path, and means for providing a second pump signal to the third optical propagation path, may comprise a coupling means which is configured to divide a main pump signal to provide the first pump signal and second pump signal.

### Claim 9 (depends on 1)

A sensor according to claim 1 wherein, the third optical propagation path is configured such that the time for a signal to propagate along the length of the third optical propagation path is at least equal to the time for a signal to propagate along the length of the first optical propagation path.

### Claim 10 (depends on 1)

A method of sensing properties of one or more structures, using a sensor according to claim 1, comprising the steps of,
arranging the first optical propagation path in cooperation with a structure whose properties are to be sensed; arranging the second optical propagation path in cooperation with a structure whose properties are to be sensed;
and propagating a first pump signal along in the first optical propagation path and propagating a second pump signal along the third optical propagation path;
amplifying the second pump signal only such that the second pump signal is amplified before the second pump signal propagate along the second propagation path;
providing a probe signal which propagates along the first and second optical propagation paths to stimulate Brillouin scattering in both the first pump signal which propagates in the first optical propagation path and in the second pump signal which propagates in the second optical propagation path;
preventing the propagation of the probe signal along the third optical propagation path; using a backscattered signal which has resulted from the Brillouin scattering, to determine properties of the one or more structures.

### Claim 11 (depends on 10)

The method according to claim 10 further comprising the step of, blocking the propagation of signals from the first optical propagation path to the second optical propagation path.

### Claim 12 (depends on 10)

The method according to claim 10 further comprising the step of, delaying the propagation of the second pump signal in the third optical propagation path.

### Claim 13 (depends on 10)

The method according to claim 10 further comprising the step of, dividing a main pump signal to provide the first and second pump signal.

### Claim 14 (depends on 10)

The method according to claim 10 further comprising the step of, remotely controlling the amplification of the second pump signal.

### Claim 15 (depends on 10)

The method according to claim 10 further comprising the step of, providing a control signal which controls the amplification provided by an amplifier which is operable to amplify a pump signal.