DE4223740A1 - Combined phase modulator and depolariser for counter-propagating wave optical fibre gyroscope - splices polarisation-maintaining fibre, located on piezoelectric cylinder, to monomode fibre coil, such that main axes of fibres are rotated by forty-five degrees w.r.t. each other - Google Patents

Combined phase modulator and depolariser for counter-propagating wave optical fibre gyroscope - splices polarisation-maintaining fibre, located on piezoelectric cylinder, to monomode fibre coil, such that main axes of fibres are rotated by forty-five degrees w.r.t. each other

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Publication number
DE4223740A1
DE4223740A1 DE4223740A DE4223740A DE4223740A1 DE 4223740 A1 DE4223740 A1 DE 4223740A1 DE 4223740 A DE4223740 A DE 4223740A DE 4223740 A DE4223740 A DE 4223740A DE 4223740 A1 DE4223740 A1 DE 4223740A1
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Germany
Prior art keywords
fibre
fiber
fibres
gyroscope
phase modulator
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
DE4223740A
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German (de)
Inventor
Eberhard Dipl Phys Kiesel
Michael Dipl Ing Neukirch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rockwell Collins Deutschland GmbH
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Teldix GmbH
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Publication date
Application filed by Teldix GmbH filed Critical Teldix GmbH
Priority to DE4223740A priority Critical patent/DE4223740A1/en
Publication of DE4223740A1 publication Critical patent/DE4223740A1/en
Ceased legal-status Critical Current

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01CMEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/58Turn-sensitive devices without moving masses
    • G01C19/64Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
    • G01C19/72Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
    • G01C19/721Details
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0128Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on electro-mechanical, magneto-mechanical, elasto-optic effects
    • G02F1/0131Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on electro-mechanical, magneto-mechanical, elasto-optic effects based on photo-elastic effects, e.g. mechanically induced birefringence
    • G02F1/0134Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on electro-mechanical, magneto-mechanical, elasto-optic effects based on photo-elastic effects, e.g. mechanically induced birefringence in optical waveguides
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0136Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation
    • G02F1/0139Polarisation scrambling devices; Depolarisers

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Gyroscopes (AREA)

Abstract

A first fibre (9) contg. a polariser is coiled round a body (10) of electrically controllable expansion. A second fibre (12) contg. a depolariser is spliced to the first so that the main axes of the fibres are rotated by 45 deg. wrt. each other. One of the two polariser-contg. fibres is connected to one end of the fibre loop (1) of the laser gyro, which consists of a monomode fibre. USE/ADVANTAGE - For phase modulating and depolarising light beams circulating in both directions in fibre loop of optical fibre gyroscope. Produces high null point stability in gyro at low manufacturing cost.

Description

Die vorliegende Erfindung betrifft eine Anordnung, welche die durch eine Faserspule in beiden Richtungen umlaufenden Lichtwellen phasenmoduliert und depolarisiert.The present invention relates to an arrangement which the by a fiber spool revolving in both directions Phase-modulated and depolarized light waves.

Eine derartige Anordnung ist aus Electronics Letters, 14. Mai 1981, Vol. 17, No. 10, S. 352, 353 bekannt. Dabei ist mit einem Ende einer Monomodefaserspule ein Depolarisator und mit dem anderen Ende ein Phasenmodulator verbunden. Der Depolarisator dient dazu, Leistungsverluste durch Polarisationsdrehung in der Faserspule zu vermeiden und Kreiseldrift erzeugende Phasenfehler zu reduzieren.Such an arrangement is from Electronics Letters, May 14th 1981, Vol. 17, No. 10, pp. 352, 353. It is with one end of a single mode fiber spool a depolarizer and with a phase modulator connected to the other end. Of the Depolarizer is used to reduce performance Avoid polarization rotation in the fiber coil and To reduce gyro drift phase errors.

Der Phasenmodulator eines Faserkreisels wird üblicherweise (vgl. DE 36 28 409) mit einem piezoelektrischen Körper realisiert, auf den einige Windungen der Faser gewickelt werden. Ist die Faserspule aus einer kostengünstigen Monomodefaser gebildet, so läßt sich eine durch den Phasenmodulator hervorgerufene Polarisationsmodulation, welche zu einer Nullpunktinstabilität des Faserkreisels führt, nur mit erheblichem Aufwand unterdrücken.The phase modulator of a fiber gyro is usually (cf. DE 36 28 409) with a piezoelectric body realized on which some turns of the fiber are wound become. Is the fiber spool from an inexpensive Monomode fiber formed, so one can by Phase modulator-induced polarization modulation, which leads to a zero point instability of the fiber gyroscope, only suppress with considerable effort.

Der Erfindung liegt nun die Aufgabe zugrunde, eine Anordnung der eingangs genannten Art anzugeben, die zu einer hohen Nullpunktstabilität des Faserkreisels beiträgt, wobei ihr Herstellungsaufwand aber möglichst gering ist.The invention is based on the object of an arrangement of the type mentioned above, which lead to a high Zero stability of the fiber gyroscope contributes, with her Manufacturing effort is as low as possible.

Erfindungsgemäß wird diese Aufgabe durch die Merkmale des Anspruchs 1 gelöst. Vorteilhafte Weiterbildungen der Erfindung gehen aus den Unteransprüchen hervor. According to the invention, this object is achieved through the features of Claim 1 solved. Advantageous developments of the invention emerge from the subclaims.  

Dadurch, daß nach der Erfindung der Phasenmodulator und der Depolarisator zu einem Bauteil kombiniert werden, verringert sich sein Prüfaufwand. Denn eine einzige Komponente kann mit weniger Aufwand geprüft werden als zwei einzelne Komponenten. Ein weiterer Vorteil dieses kombinierten Bauteils besteht darin, daß es weniger Verbindungsstellen (Spleißstellen) erfordert, wenn es in den Faserkreisel eingefügt wird, als zwei einzelne voneinander getrennte Bauteile.The fact that according to the invention, the phase modulator and Depolarizer combined into one component, reduced himself his testing effort. Because a single component can less effort is checked than two individual components. Another advantage of this combined component is in that there are fewer joints (splices) required when inserted into the fiber top, as two separate components.

Anhand eines in der Zeichnung dargestellten Ausführungsbeispiels wird nachfolgend die Erfindung näher erläutert.Using one shown in the drawing The invention is described in more detail below explained.

Fig. 1 zeigt einen prinzipiellen Aufbau eines Faserkreisels, Fig. 1 shows a basic structure of a fiber optic gyroscope,

Fig. 2 zeigt einen Phasenmodulator kombiniert mit einem Depolarisator und Fig. 2 shows a phase modulator combined with a depolarizer and

Fig. 3 zeigt eine Realisierung des Depolarisators. Fig. 3 shows a realization of the depolarizer.

Ein der Fig. 1 zu entnehmender Faserkreisel besteht im wesentlichen aus einer Faserspule 1, in die von einer Laserdiode oder Leuchtdiode L Licht eingespeist wird. Und zwar wird das Licht mit Hilfe von Kopplern 3, 4 in zwei gegenläufige Lichtwellen aufgeteilt. Diese beiden gegenläufigen Lichtwellen erhalten in der Faserspule 1 in Abhängigkeit von der Winkelgeschwindigkeit, mit der die Faserspule gedreht wird, einen Laufzeitunterschied. Die an den beiden Ausgängen der Faserspule 1 erscheinenden phasenmodulierten optischen Signalanteile werden im Koppler 4 einander überlagert und einer Photodiode 5 zugeführt, welche das optische Signal in ein elektrisches Signal umwandelt. Eine Auswerteeinheit 6, ermittelt aus dem Spektrum des Ausgangssignals der Photodiode 6 die Drehrate des Kreisels. A of Fig. 1 to be removed Direction fiber gyro consists essentially of a fiber coil 1 is fed in by a laser diode or light emitting diode L light. The light is split into two opposing light waves with the help of couplers 3 , 4 . These two opposing light waves receive a transit time difference in the fiber spool 1 as a function of the angular speed at which the fiber spool is rotated. The phase-modulated optical signal components appearing at the two outputs of the fiber coil 1 are superimposed on one another in the coupler 4 and fed to a photodiode 5 , which converts the optical signal into an electrical signal. An evaluation unit 6 determines the rate of rotation of the gyro from the spectrum of the output signal of the photodiode 6 .

Damit es nicht zu einem Intensitätsverlust der aus der Faserspule austretenden optischen Teilsignale, die im Koppler 4 einander überlagert und dann der Photodiode zugeführt werden, kommt, ist in bekannter Weise zwischen den Kopplern 4 und 3 in dem Signalpfad, der sowohl die zur Faserspule hinlaufenden als auch die aus der Faserspule rücklaufende Lichtwellen führt, ein Polarisator 7 eingefügt. Dieser Polarisator läßt nur Wellen einer bestimmten Polarisationsrichtung passieren und unterdrückt Wellen aller anderen Polarisationsrichtungen.So that there is no loss of intensity of the optical partial signals emerging from the fiber spool, which are superimposed on one another in the coupler 4 and then fed to the photodiode, is in a known manner between the couplers 4 and 3 in the signal path, which both leads to the fiber spool and also leads the light waves returning from the fiber coil, a polarizer 7 inserted. This polarizer only allows waves of a certain direction of polarization to pass and suppresses waves of all other directions of polarization.

Wie bereits gesagt, werden die in der Faserspule 1 entgegengesetzt umlaufenden Lichtwellen phasenmoduliert. Zu diesem Zweck befindet sich an einem Ende der Faserspule 1 ein Phasenmodulator, welcher in der Fig. 1 durch den Block 8 angedeutet ist.As already said, the light waves rotating in opposite directions in the fiber coil 1 are phase-modulated. For this purpose, there is a phase modulator at one end of the fiber spool 1 , which is indicated by block 8 in FIG. 1.

In den eingangs zitierten Electronics Letters ist angeführt, daß in den Faserkreisel ein Depolarisator einzufügen ist, der für eine quasistatistische Polarisationsverteilung der in der Faserspule 1 in entgegengesetzten Richtungen umlaufenden Lichtwellen sorgt.In the electronics letters cited at the beginning it is stated that a depolarizer is to be inserted into the fiber gyroscope, which ensures a quasi-statistical polarization distribution of the light waves circulating in the fiber coil 1 in opposite directions.

Diese Maßnahme ist erforderlich, wenn eine normale, d. h. die Polarisation nicht erhaltende Monomodefaser verwendet wird.This measure is necessary if a normal, i.e. H. the Single mode fiber not receiving polarization is used.

Der in Fig. 1 mit 8 bezeichnete Block enthält neben dem Phasenmodulator auch den Depolarisator. Diese beiden Bauelemente sind, wie in Fig. 2 dargestellt, zu einem Bauteil vereinigt.The block denoted by 8 in FIG. 1 contains not only the phase modulator but also the depolarizer. As shown in FIG. 2, these two components are combined to form one component.

Die Funktion des Phasenmodulators erfüllt ein mit einer polarisationserhaltenen Faser 9 bewickelter piezoelektrischer Zylinder 10, dessen radiale Ausdehnung durch eine angelegte Wechselspannung 11 steuerbar ist. Ein Ende der polarisationserhaltenden Faser 9 ist mit der Monomodefaserspule 1 verspleißt.The function of the phase modulator is performed by a piezoelectric cylinder 10 wound with a polarization-maintaining fiber 9 , the radial extent of which can be controlled by an applied AC voltage 11 . One end of the polarization-maintaining fiber 9 is spliced to the single-mode fiber coil 1 .

Dadurch, daß für den Phasenmodulator eine polarisationserhaltende Faser 9 eingesetzt wird, bleibt störende Polarisationsmodulation sehr gering.Because a polarization-maintaining fiber 9 is used for the phase modulator, disruptive polarization modulation remains very low.

Dieselbe auf dem piezoelektrischen Zylinder 10 aufgewickelte Faser 9 ist Teil des Depolarisators. Vervollständigt wird dieser Depolarisator durch eine weitere polarisationserhaltende Faser 12, welche an die Faser 9 so angespleißt ist, daß (wie Fig. 3 zeigt) die Hauptachsen X1, Y1 der einen Faser 12 gegenüber den Hauptachsen X2, Y2 der anderen Faser 9 um einen Winkel von 45° verdreht sind.The same fiber 9 wound on the piezoelectric cylinder 10 is part of the depolarizer. This depolarizer is completed by a further polarization-maintaining fiber 12 , which is spliced onto the fiber 9 such that (as FIG. 3 shows) the main axes X1, Y1 of one fiber 12 with respect to the main axes X2, Y2 of the other fiber 9 by an angle are rotated by 45 °.

Claims (3)

1. Anordnung, welche die durch eine Faserspule eines Faserkreisels in beiden Richtungen umlaufenden Lichtwellen phasenmoduliert und depolarisiert, dadurch gekennzeichnet, daß eine erste polarisationserhaltende Faser (9), welche um einen Körper (10) gewickelt ist, dessen Ausdehnung elektrisch steuerbar ist, und eine zweite polarisationserhaltende Faser (12) vorhanden sind, welche mit der ersten Faser (9) so verspleißt ist, daß die Hauptachsen (X1, Y2, X2, Y2) der beiden Fasern (9, 12) um einen Winkel von 45° gegeneinander verdreht sind.1. Arrangement which phase modulates and depolarizes the light waves rotating in both directions through a fiber coil of a fiber gyroscope, characterized in that a first polarization-maintaining fiber ( 9 ) which is wound around a body ( 10 ), the extent of which is electrically controllable, and a second polarization-maintaining fiber ( 12 ) are present, which is spliced to the first fiber ( 9 ) so that the main axes (X1, Y2, X2, Y2) of the two fibers ( 9 , 12 ) are rotated relative to one another by an angle of 45 ° . 2. Anordnung nach Anspruch 1, dadurch gekennzeichnet, daß eine der beiden polarisationserhaltenden Fasern (9, 12) mit einem Ende der Faserspule (1) verbunden ist.2. Arrangement according to claim 1, characterized in that one of the two polarization-maintaining fibers ( 9 , 12 ) is connected to one end of the fiber coil ( 1 ). 3. Anordnung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Faserspule (1) aus einer Monomodefaser gebildet ist.3. Arrangement according to claim 1 or 2, characterized in that the fiber spool ( 1 ) is formed from a single-mode fiber.
DE4223740A 1992-07-18 1992-07-18 Combined phase modulator and depolariser for counter-propagating wave optical fibre gyroscope - splices polarisation-maintaining fibre, located on piezoelectric cylinder, to monomode fibre coil, such that main axes of fibres are rotated by forty-five degrees w.r.t. each other Ceased DE4223740A1 (en)

Priority Applications (1)

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DE4223740A DE4223740A1 (en) 1992-07-18 1992-07-18 Combined phase modulator and depolariser for counter-propagating wave optical fibre gyroscope - splices polarisation-maintaining fibre, located on piezoelectric cylinder, to monomode fibre coil, such that main axes of fibres are rotated by forty-five degrees w.r.t. each other

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DE4223740A DE4223740A1 (en) 1992-07-18 1992-07-18 Combined phase modulator and depolariser for counter-propagating wave optical fibre gyroscope - splices polarisation-maintaining fibre, located on piezoelectric cylinder, to monomode fibre coil, such that main axes of fibres are rotated by forty-five degrees w.r.t. each other

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DE4223740A1 true DE4223740A1 (en) 1994-01-20

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996010187A1 (en) * 1994-09-27 1996-04-04 Citeq Optical interferometric current sensor and a method for measuring an electrical current
DE19803223C1 (en) * 1998-01-28 1999-07-29 Litef Gmbh Fiber-optic Sagnac interferometer e.g. for gyroscope
WO1999042891A1 (en) * 1998-02-21 1999-08-26 Donam Systems Inc. Optical fiber polarization scrambler and operating parameter input method therefor
WO2000039618A1 (en) * 1998-12-29 2000-07-06 Honeywell Inc. Method for fabrication of an all fiber polarization retardation device
WO2000049438A1 (en) * 1999-02-19 2000-08-24 Protodel International Limited Polarisation control
WO2003060427A1 (en) * 2002-01-03 2003-07-24 Honeywell International Inc. Symmetrical depolarized fiber optic gyroscope
EP2239542A1 (en) * 2008-01-10 2010-10-13 Kabushiki Kaisha Toshiba Phase modulator, phase modulator assembly, and optical sensor
CN104713542A (en) * 2013-12-11 2015-06-17 中国航空工业第六一八研究所 Non-fusion making method of high precision optical fiber gyroscope

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0476673A1 (en) * 1990-09-21 1992-03-25 Japan Aviation Electronics Industry, Limited Fiber optic gyro

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0476673A1 (en) * 1990-09-21 1992-03-25 Japan Aviation Electronics Industry, Limited Fiber optic gyro

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JP 2-240511 (A) In: Patents Abstr. of Japan, Sect. P, Vol. 14 (1990), Nr. 561, (P-1142) *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996010187A1 (en) * 1994-09-27 1996-04-04 Citeq Optical interferometric current sensor and a method for measuring an electrical current
DE19803223C1 (en) * 1998-01-28 1999-07-29 Litef Gmbh Fiber-optic Sagnac interferometer e.g. for gyroscope
US6563587B1 (en) 1998-01-28 2003-05-13 Litef Gmbh Fiber optic Sagnac interferometer with spatial filter
US6266456B1 (en) 1998-02-21 2001-07-24 Donam Systems Inc. Optical fiber polarization scrambler and operating parameter input method therefor
WO1999042891A1 (en) * 1998-02-21 1999-08-26 Donam Systems Inc. Optical fiber polarization scrambler and operating parameter input method therefor
US6535654B1 (en) 1998-12-29 2003-03-18 Nxtphase Technologies, Srl Method for fabrication of an all fiber polarization retardation device
WO2000039618A1 (en) * 1998-12-29 2000-07-06 Honeywell Inc. Method for fabrication of an all fiber polarization retardation device
WO2000049438A1 (en) * 1999-02-19 2000-08-24 Protodel International Limited Polarisation control
WO2003060427A1 (en) * 2002-01-03 2003-07-24 Honeywell International Inc. Symmetrical depolarized fiber optic gyroscope
US6801319B2 (en) 2002-01-03 2004-10-05 Honeywell International, Inc. Symmetrical depolarized fiber optic gyroscope
EP2239542A1 (en) * 2008-01-10 2010-10-13 Kabushiki Kaisha Toshiba Phase modulator, phase modulator assembly, and optical sensor
EP2239542A4 (en) * 2008-01-10 2014-09-10 Toshiba Kk Phase modulator, phase modulator assembly, and optical sensor
CN104713542A (en) * 2013-12-11 2015-06-17 中国航空工业第六一八研究所 Non-fusion making method of high precision optical fiber gyroscope
CN104713542B (en) * 2013-12-11 2017-07-25 中国航空工业第六一八研究所 A kind of high-precision optical fiber gyro weldless preparation method

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