CA2479245A1 - Method and apparatus for producing depolarized light - Google Patents
Method and apparatus for producing depolarized light Download PDFInfo
- Publication number
- CA2479245A1 CA2479245A1 CA002479245A CA2479245A CA2479245A1 CA 2479245 A1 CA2479245 A1 CA 2479245A1 CA 002479245 A CA002479245 A CA 002479245A CA 2479245 A CA2479245 A CA 2479245A CA 2479245 A1 CA2479245 A1 CA 2479245A1
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- polarization
- light
- beam splitter
- coupled
- output
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- 238000000034 method Methods 0.000 title claims abstract 8
- 230000010287 polarization Effects 0.000 claims abstract 23
- 230000003111 delayed effect Effects 0.000 claims abstract 2
- 239000000835 fiber Substances 0.000 claims 12
- 230000002999 depolarising effect Effects 0.000 claims 2
- 238000005562 fading Methods 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 abstract 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/344—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using polarisation
- G01D5/345—Polarising encoders
-
- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35303—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using a reference fibre, e.g. interferometric devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35383—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Communication System (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
Abstract
A method and apparatus for producing depolarized light that is useful in forming interrogation signals for an optical sensor array and demodulator having reduced polarization-induced fading and phase noise. The depolarized light is produced by splitting a light beam, delaying a first orthogonal component of the light beam with respect to a second orthogonal component of the light beam using a predefined delay, while maintaining the polarization of the first orthogonal component and the polarization of the second orthogonal component. The delayed light beams are combined to produce a depolarized light beam by selecting a predefined delay that causes an interference signal having a delay equal to the predefined delay to be suppressed during a demodulation process.
Claims (16)
1. Apparatus for depolarizing light comprising:
a beam splitter having an input and two outputs, where a light beam from a first output has a polarization that is orthogonal to a polarization of a light beam from a second output; and a beam combiner having a first input coupled to the first output of the beam splitter via a first fiber, a second input coupled to the second output of the beam splitter via a second fiber, and an output that produces depolarized light, where the first and second fibers are polarization maintaining fibers and the second fiber has a length that provides a predefined delay with respect to the first fiber such that an interference signal having a delay equal to the predefined delay will be suppressed during a demodulation process.
a beam splitter having an input and two outputs, where a light beam from a first output has a polarization that is orthogonal to a polarization of a light beam from a second output; and a beam combiner having a first input coupled to the first output of the beam splitter via a first fiber, a second input coupled to the second output of the beam splitter via a second fiber, and an output that produces depolarized light, where the first and second fibers are polarization maintaining fibers and the second fiber has a length that provides a predefined delay with respect to the first fiber such that an interference signal having a delay equal to the predefined delay will be suppressed during a demodulation process.
2. The apparatus of claim 1 further comprising a light source coupled to the beam splitter.
3. The apparatus of claim 2 further comprising a polarization controller, coupled between the light source and the input of the beam sputter, for equalizing signal power levels at the first and second outputs of the beam splitter.
4. The apparatus of claim 1 further comprising a light source, coupled to the beam splitter, having a coherence length that is less than a length of an interrogation pulse that is formed using the depolarized light.
5. The apparatus of claim 4 further comprising a polarization controller, coupled to the input of the beam splitter, for equalizing signal power levels at the first and second outputs of the beam splitter.
6. The apparatus of claim 1 further comprising a light source, coupled to the beam splitter, having a frequency swept output and the predefined delay is selected to ensure that a cross-correlation between orthogonal polarizations of the source do not appear in extracted signal frequencies within a receiver.
7. The apparatus of claim 6 further comprising a polarization controller, coupled to the input of the beam splitter, for equalizing signal power levels at the first and second outputs of the beam splitter.
8. Apparatus for depolarizing light comprising:
means for splitting a light beam having an input and two outputs, where a light beam from a first output has a polarization that is orthogonal to a polarization of a light beam from a second output; and means for combining two light beams having a first input coupled to the first output of the beam splitter via a first fiber, a second input coupled to the second output of the beam splitter via a second fiber, and an output that produces depolarized light, where the first and second fibers are polarization maintaining fibers and the second fiber comprises a means for providing a predefined delay with respect to the first fiber such that an interference signal having a delay equal to the predefined delay will be suppressed during a demodulation process.
means for splitting a light beam having an input and two outputs, where a light beam from a first output has a polarization that is orthogonal to a polarization of a light beam from a second output; and means for combining two light beams having a first input coupled to the first output of the beam splitter via a first fiber, a second input coupled to the second output of the beam splitter via a second fiber, and an output that produces depolarized light, where the first and second fibers are polarization maintaining fibers and the second fiber comprises a means for providing a predefined delay with respect to the first fiber such that an interference signal having a delay equal to the predefined delay will be suppressed during a demodulation process.
9. The apparatus of claim 8 further comprising a light source coupled to the beam splitter.
10. The apparatus of claim 8 further comprising means for controlling polarization, coupled to the input of the beam splitting means, where the polarization controlling means equalizes signal power levels at the first and second outputs of the beam splitter.
11. The apparatus of claim 8 further comprising a light source, coupled to the beam splitting means, having a coherence length that is less than a length of an interrogation pulse that is formed using the depolarized light.
12. The apparatus of claim 11 further comprising means for controlling polarization, coupled to the input of the beam sputter, where the polarization controlling means equalizes signal power levels at the first and second outputs of the beam splitter.
13. The apparatus of claim 8 further comprising a light source, coupled to the beam splitting means, having a frequency swept output and the predefined delay is selected to ensure that a cross-correlation between orthogonal polarizations of the source do not appear in extracted signal frequencies within a receiver.
14. The apparatus of claim 13 further comprising means for controlling polarization, coupled to the input of the beam splitter, where the polarization controlling means equalizes signal power levels at the first and second outputs of the beam splitter.
15. A method of forming depolarized light comprising:
splitting a light beam into two orthogonal components;
delaying a first orthogonal component with respect to a second orthogonal component using a predefined delay, while maintaining a polarization of the first orthogonal component and a polarization of the second orthogonal component;
and combining the delayed first orthogonal component with the second orthogonal component to produce a depolarized output light beam, where said predefined delay is selected to cause an interference signal having a delay equal to the predefined delay to be suppressed during a demodulation process.
splitting a light beam into two orthogonal components;
delaying a first orthogonal component with respect to a second orthogonal component using a predefined delay, while maintaining a polarization of the first orthogonal component and a polarization of the second orthogonal component;
and combining the delayed first orthogonal component with the second orthogonal component to produce a depolarized output light beam, where said predefined delay is selected to cause an interference signal having a delay equal to the predefined delay to be suppressed during a demodulation process.
16. The method of claim 15 further comprising controlling a polarization of the light beam to equalize the signal power levels of the two orthogonal components.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/649,590 | 2003-08-27 | ||
| US10/650,117 | 2003-08-27 | ||
| US10/650,117 US7081959B2 (en) | 2003-08-27 | 2003-08-27 | Method and apparatus for providing polarization insensitive signal processing for interferometric sensors |
| US10/649,590 US7088878B2 (en) | 2003-08-27 | 2003-08-27 | Method and apparatus for producing depolarized light |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2479245A1 true CA2479245A1 (en) | 2005-02-27 |
| CA2479245C CA2479245C (en) | 2010-01-12 |
Family
ID=33135364
Family Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002479245A Active CA2479245C (en) | 2003-08-27 | 2004-08-25 | Method and apparatus for producing depolarized light |
| CA002479081A Active CA2479081C (en) | 2003-08-27 | 2004-08-25 | Method and apparatus for providing polarization insensitive signal processing for interferometric sensors |
| CA2639131A Active CA2639131C (en) | 2003-08-27 | 2004-08-25 | Method and apparatus for providing polarization insensitive signal processing for interferometric sensors |
Family Applications After (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002479081A Active CA2479081C (en) | 2003-08-27 | 2004-08-25 | Method and apparatus for providing polarization insensitive signal processing for interferometric sensors |
| CA2639131A Active CA2639131C (en) | 2003-08-27 | 2004-08-25 | Method and apparatus for providing polarization insensitive signal processing for interferometric sensors |
Country Status (2)
| Country | Link |
|---|---|
| CA (3) | CA2479245C (en) |
| GB (2) | GB2405469B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7466425B2 (en) | 2005-04-22 | 2008-12-16 | Agilent Technologies, Inc. | Elementary matrix based optical signal/network analyzer |
| US10247581B2 (en) | 2014-04-28 | 2019-04-02 | Optoplan As | Interferometric optical fibre sensor system and method of interrogation |
| WO2016086310A1 (en) | 2014-12-04 | 2016-06-09 | Hifi Engineering Inc. | Optical interrogator for performing interferometry using fiber bragg gratings |
| GB2568305B (en) | 2017-11-13 | 2022-06-15 | Univ Cranfield | A fibre optic sensing device |
| CN109631962B (en) * | 2018-12-20 | 2020-12-04 | 中国人民解放军国防科技大学 | Multi-frequency carrier polarization modulation and demodulation system and method based on PGC scheme |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5173743A (en) * | 1991-05-28 | 1992-12-22 | Litton Systems, Inc. | Fiber optical time-division-multiplexed unbalanced pulsed interferometer with polarization fading compensation |
| EP0570151B1 (en) * | 1992-05-08 | 1997-10-29 | Kokusai Denshin Denwa Co., Ltd | Optical transmitter with the signal light of reduced degree of polarization and optical depolarizing circuit |
| US6574015B1 (en) * | 1998-05-19 | 2003-06-03 | Seagate Technology Llc | Optical depolarizer |
| NO322073B1 (en) * | 1999-06-23 | 2006-08-07 | Optoplan As | Polarization Control Procedure |
| CA2393172C (en) * | 2002-07-12 | 2008-11-04 | Itf Technologies Optiques Inc.- Itf Optical Technologies Inc. | All-fiber linear design depolarizer |
-
2004
- 2004-08-25 CA CA002479245A patent/CA2479245C/en active Active
- 2004-08-25 CA CA002479081A patent/CA2479081C/en active Active
- 2004-08-25 CA CA2639131A patent/CA2639131C/en active Active
- 2004-08-26 GB GB0419047A patent/GB2405469B/en active Active
- 2004-08-27 GB GB0419163A patent/GB2406166B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CA2479081A1 (en) | 2005-02-27 |
| CA2479245C (en) | 2010-01-12 |
| GB2405469A (en) | 2005-03-02 |
| GB2406166A (en) | 2005-03-23 |
| CA2639131C (en) | 2010-01-26 |
| GB0419047D0 (en) | 2004-09-29 |
| GB2406166B (en) | 2006-07-05 |
| GB0419163D0 (en) | 2004-09-29 |
| GB2405469B (en) | 2006-11-29 |
| CA2479081C (en) | 2008-11-25 |
| CA2639131A1 (en) | 2005-02-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |