JP2000046565A - Optical fiber gyro - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the optical fiber gyro which has other constituent elements isolated from a coil. SOLUTION: The optical fiber gyro is equipped with a 1st optical coupler 4 which makes the light emitted by a light source 1 into two pieces of luminous flux, a phase modulator 7 including an optical fiber coil 8 where the two pieces of luminous flux are propagated mutually reversely and a modulating signal generator, a 2nd optical coupler 5 which makes the interference light between the two pieces of luminous flux emitted by the optical fiber coil 8 branch, and a photodetector 3 which detects the interference light made to branch by the 2nd optical coupler 5, and the path of the light is formed from the light source 1 to the photodetector 3 through the 2nd optical coupler 5, 1st optical coupler 4, optical fiber coil 8, phase modulator 7, 1st optical coupler 4, and 2nd optical coupler 5; and the 2nd optical coupler 5 and 1st optical coupler 4 are connected through a long light source optical fiber 21 for drawing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber gyro, and more particularly, to an optical fiber gyro in which a light source or a light source and other components are arranged separately from a sensing unit including an optical fiber coil.

[0002]

2. Description of the Related Art A conventional example of an optical fiber gyro will be described with reference to FIG. The light emitted from the light source 1 passes through the second optical coupler 5, is polarized by the polarizer 6, and is branched into two by the first optical coupler 4. The bifurcated light passes through the optical fiber coil 8 and the phase modulator 7 in left and right opposite directions to each other. After passing through, the optical receiver 3 detects the interference state of the left and right bidirectional light, thereby measuring the input angular velocity of the optical fiber coil 8 around the central axis. These components constituting the optical fiber gyro are positioned and fixed at one place adjacent to each other. That is, the optical fiber gyro includes a modulation signal generator (not shown) for driving the light source 1, the light receiver 3, and the phase modulator 7, which are constituent elements thereof.
The components including the second optical coupler 5, the first optical coupler 4, and other electric components are positioned near the sensing unit 30 including the optical fiber coil 8, so that the components and the optical fiber coil 8 are eventually common. It is housed and fixed integrally in the housing.

[0003]

As described above, in the conventional example of the optical fiber gyro, all the components are collectively housed in a common housing, so that the optical fiber gyro is not suitable for the optical fiber gyro such as a high temperature environment. When installed and used in an environment area that is not necessarily good, the components are exposed to high temperatures, and the light source 1, the light receiver 3,
Other electrical components are exposed to high temperatures. In this case, the operating temperature limit of the optical fiber gyro is limited by the element having the lowest operating temperature limit among the components. Assuming that the element having the lowest operating temperature limit is the light source 1, the operating temperature limit of the optical fiber gyro is determined by the temperature resistance characteristics of the light source 1. Further, when components including the light source 1 and other components are arranged near the sensing unit 30 including the optical fiber coil 8, the dimensions of the sensing unit 30 are increased by the amount of the components, and the optical fiber gyro for the moving object is increased. It is not preferable for installation.

The present invention is to provide an optical fiber gyro that solves the above-mentioned problem by separating components other than the sensing section 30 of the optical fiber gyro from the sensing section 30 including the optical fiber coil 8.

[0005]

A light source, a first optical coupler for splitting light emitted from the light source into two light beams, an optical fiber coil for transmitting two light beams in opposite directions, and A phase modulator 7 including a modulation signal generator 10, a second optical coupler 5 for branching interference light of two outgoing light beams emitted from the optical fiber coil, and a light receiving device for detecting interference light branched by the second optical coupler 5 The optical path is from the light source 1 to the second optical coupler 5, the first optical coupler 4, the optical fiber coil 8 and the phase modulator 7, the first optical coupler 4, the second
In the optical fiber gyro formed in the photodetector 3 via the optical coupler 5 of the above, an optical fiber gyro in which the light source 1 and the second optical coupler 5 are connected via a long light source optical fiber 21 for stretching did.

Further, the light source 1, the first optical coupler 4, which splits the light emitted from the light source 1 into two light beams, the optical fiber coil 8 in which the two light beams propagate in opposite directions, and the generation of a modulation signal Modulator 7 including a modulator 10, a second branching device for splitting interference light of two emitted light beams emitted from an optical fiber coil
And a light receiver 3 for detecting the interference light branched from the second optical coupler 5, and the light path from the light source 1 to the second
Optical coupler 5, first optical coupler 4, optical fiber coil 8
In the optical fiber gyro formed in the light receiver 3 via the phase modulator 7, the first optical coupler 4, and the second optical coupler 5, the optical fiber gyro is provided between the second optical coupler 5 and the first optical coupler 4. An optical fiber gyro connected via a long stretching light source optical fiber 21 was constructed.

[0007] Claim 3: Claims 1 and 2
In the optical fiber gyro described in any one of the above, an optical fiber gyro in which the modulation signal generator 10 is separated and separated from the phase modulator 7 is formed. Further, claim 4:
4. The optical fiber gyro according to claim 3, further comprising a modulation optical signal light source 9 for converting an electrical modulation signal generated by the modulation signal generator 10 into a modulation optical signal. A light receiving device for receiving light;
An optical fiber gyro that amplifies the output of the optical modulator and drives the phase modulator 7 and connects the optical signal light source 9 for modulation and the photodetector 12 through a long optical fiber 22 for extension. Was configured.

[0008] Claim 5: In the optical fiber gyro according to claim 3, a modulation optical signal light source 9 for converting an electrical modulation signal generated by a modulation signal generator 10 into a modulation optical signal. A light receiver 12 for receiving the optical signal for modulation; an amplifier 13 for amplifying the output of the light receiver 12 and driving the phase modulator 7; The optical receiver gyro was coupled to the drawing light source fiber 21 via the multiplexing coupler 14, and the light receiver 12 was connected to the drawing light source fiber 21 via the second demultiplexing / multiplexing coupler 15.

Claim 6: Claims 4 and 5
In the optical fiber gyro described in any one of the above, a third optical coupler is provided between the first optical coupler 4 and the optical fiber coil 8.
The optical fiber gyro was connected through the stretching optical fiber 23 and connected between the phase modulator 7 and the optical fiber coil 8 through the fourth stretching optical fiber 24.

[0010] Claim 7: Claims 1 to 6
In the optical fiber gyro described in any of the above, any of the drawing light source optical fiber 21, the drawing modulation signal optical fiber 22, the third drawing optical fiber 23, and the fourth drawing optical fiber 24 are all used. An optical fiber gyro having an optical connector was constructed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In these figures, FIG.
The same reference numerals are given to members common to the conventional example. First, a first embodiment will be described with reference to FIG. This first embodiment shows an example of an optical fiber gyro in which only the light source 1 is separated from the sensing unit 30 including the optical fiber coil 8. The sensing unit 30 and the light source 1 are connected via the optical connector 2 and a long light source optical fiber 21 for extension, and the light source 1 is separated from the sensing unit 30.
Although it is easy to focus on the light source 1 and separate it from the sensing unit 30 via the elongated light source optical fiber 21 for elongation, it is possible to improve the environmental resistance of the optical fiber gyro. The fluctuation of the emission wavelength of the light source 1 due to the temperature fluctuation has a great effect on the operation characteristics of the optical fiber gyro.
The temperature characteristic of the optical fiber gyro can be kept good even when the sensing unit 30 is installed in an environment region where temperature fluctuation is large only by a very easy configuration change of being separated from zero. The second embodiment will be described with reference to FIG. In the second embodiment, a light source 1, a light receiver 3, a second optical coupler 5,
An example in which the polarizer 6 is separated from the sensing unit 30 including the optical fiber coil 8 via the optical connector 2 and the elongated light source optical fiber 21 for elongation is shown. As compared with the first embodiment in which only the light source 1 is separated from the sensing unit 30, the environment resistance can be further improved, and the sensing unit 30 can be made smaller.

A third embodiment will be described with reference to FIG.
The third embodiment is an example in which the modulation signal generator 10 is further separated from the sensing unit 30 in the second embodiment of FIG. At this time, the electrical modulation signal generated by the modulation signal generator 10 is supplied to the modulation optical signal light source 9 to be converted into the modulation optical signal, and is sensed via the dedicated extension modulation signal optical fiber 22. The data is transmitted to the unit 30. 1
Numeral 1 designates the extension modulation signal optical fiber 22 as the sensing unit 30
This is an optical connector that connects to. The modulation optical signal transmitted to the sensing unit 30 via the extension modulation signal optical fiber 22 is received by the modulation optical signal receiver 12, converted into an electric signal, and amplified by the amplifier 13. The phase modulator 7 is driven by the modulation signal amplified by the amplifier 13.
As described above, the modulation signal generator 10 is connected to the sensing unit 30.
By separating from the sensor, the size of the sensing unit 30 can be further reduced, and the modulation signal transmitted to the sensing unit 30 can be sufficiently stabilized, so that the performance of the gyro can be improved. Then, by transmitting the modulation signal through the dedicated extension modulation signal optical fiber 22, the noise resistance of the modulation signal is also improved, which also contributes to the improvement of the gyro performance.

A fourth embodiment will be described with reference to FIG.
The fourth embodiment differs from the third embodiment in FIG. 3 in that the light source for modulation is generated by the light source for modulation 9 generated by the light source for modulation 9 without using the dedicated optical fiber 22 for extension. Light source optical fiber 2 for stretching separated from sensing unit 30
1 shows an example of transmission via an I. In this case, the modulation optical signal light source 9 is coupled to the stretching light source optical fiber 21 via the first demultiplexing / multiplexing optical coupler 14. Then, the optical signal receiver for modulation 12 is coupled to the light source optical fiber for extension 21 via the second demultiplexing / multiplexing optical coupler 15 in the sensing unit 30. The fourth embodiment has a configuration in which the sensing unit 30 and other components are separated from each other by an amount that eliminates the need for the dedicated optical fiber extending modulation signal optical fiber 22 for transmitting the modulation optical signal to the sensing unit 30. It can be simplified.
It is extremely easy to add the first demultiplexing and multiplexing optical coupler 14 and the second demultiplexing and multiplexing optical coupler 15, and this does not impose a special burden.

A fifth embodiment will be described with reference to FIG.
The sensing unit 30 is composed of only the optical fiber coil 8;
An example in which all the other components are separated from the sensing unit 30 is shown. The first optical coupler 4 and the optical fiber coil 8 are connected via a third stretching optical fiber 23, and the phase modulator 7 and the optical fiber coil 8 are connected via a fourth stretching optical fiber 24. Connected.

[0015]

As described above, according to the present invention, a light source, a light receiving device, and other components having low environmental resistance are sent from a sensing portion including an optical fiber coil via a light source optical fiber for extension and an optical connector. By arranging them at a distance from each other, these component lights are less likely to be affected by high temperatures and other adverse environments.In the end, even if the optical fiber gyro is used in a poor environment, its performance Is not reduced. For example, when using an optical fiber gyro in a high temperature environment,
Since the optical receiver and other components greatly affected by heat can be arranged in a favorable environment area, the optical fiber gyro can be used even at a temperature higher than the service limit temperature of these components. Since the light source and other components are arranged separately from and separated from the sensing unit including the optical fiber coil, the size of the sensing unit can be reduced accordingly, and the installation conditions of the optical fiber gyro can be reduced. By connecting the sensing unit and other components via the stretching optical fiber and the optical connector, the sensing unit and the other components are separated to facilitate movement and installation of the optical fiber gyro. Can be.

When the modulation signal generator, which is an electric circuit, is disposed at a long distance from the sensing unit, noise may be mixed into the modulation electric signal due to transmission of the modulation electric signal over a long distance. Increase. Therefore, by converting the electric signal for modulation into an optical signal and transmitting the optical signal through the optical fiber for extending the modulation signal, it is possible to extremely reduce the noise in the signal. Further, by adopting a configuration in which the first and second demultiplexing and multiplexing optical couplers are used to transmit the optical signal for modulation by commonly using the light source optical fiber for extension for transmitting the light source light of the optical fiber gyro. The structure of the light transmission path can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment.

FIG. 2 is a diagram illustrating a second embodiment.

FIG. 3 is a diagram illustrating a third embodiment.

FIG. 4 is a diagram illustrating a fourth embodiment.

FIG. 5 is a diagram illustrating a fifth embodiment.

FIG. 6 illustrates a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 optical connector 3 light receiver 4 first optical coupler 5 second optical coupler 6 polarizer 7 phase modulator 8 optical fiber coil 9 modulation optical signal light source 10 modulation signal generator 11 optical connector 12 modulation optical signal Optical receiver 13 Amplifier 14 First demultiplexing / multiplexing optical coupler 15 Second demultiplexing / multiplexing optical coupler 16 Optical connector 17 Optical connector 21 Light source optical fiber for extension 22 Modulation signal optical fiber for extension 23 Third optical fiber for extension 24 Fourth drawing optical fiber 30 sensing part

Claims (7)

[Claims] 1. A light source, a first optical coupler that splits light emitted from the light source into two light beams, an optical fiber coil through which two light beams propagate in opposite directions, and a phase modulator including a modulation signal generator; A second optical coupler that branches the interference light of the two emitted light beams emitted from the fiber coil; and a photodetector that detects the interference light that is branched by the second optical coupler, and the light path is from the light source to the second light. In an optical fiber gyro formed on a photodetector via a coupler, a first optical coupler, an optical fiber coil and a phase modulator, a first optical coupler, and a second optical coupler, between a light source and a second optical coupler The optical fiber gyro is connected through a long stretching light source optical fiber. 2. A light source, a first optical coupler that splits light emitted from the light source into two light beams, an optical fiber coil through which two light beams propagate in opposite directions, and a phase modulator including a modulation signal generator, and light. A second optical coupler that branches the interference light of the two emitted light beams emitted from the fiber coil; and a photodetector that detects the interference light that is branched by the second optical coupler, and the light path is from the light source to the second light. In an optical fiber gyro formed on a photodetector via a coupler, a first optical coupler, an optical fiber coil and a phase modulator, a first optical coupler, and a second optical coupler, a second optical coupler and a first optical coupler are provided. An optical fiber gyro, wherein the optical couplers are connected via a long stretching light source optical fiber. 3. The optical fiber gyro according to claim 1, wherein the modulation signal generator is separated from the phase modulator. 4. The optical fiber gyro according to claim 3, further comprising a modulation optical signal light source for converting an electrical modulation signal generated by the modulation signal generator into a modulation optical signal. A light receiving device for receiving an optical signal, an amplifier for amplifying the output of the light receiving device and driving a phase modulator, and a long extending modulation signal optical fiber between the light signal light source for modulation and the light receiving device. An optical fiber gyro, wherein the optical fiber gyro and the optical fiber gyro are connected to each other. 5. The optical fiber gyro according to claim 3, further comprising a modulation optical signal light source for converting an electrical modulation signal generated by the modulation signal generator into a modulation optical signal. A light receiving device for receiving an optical signal; an amplifier for amplifying an output of the light receiving device to drive a phase modulator; and a light source for modulation is a light source for extension through a first demultiplexing / multiplexing coupler. An optical fiber gyro coupled to an optical fiber, wherein the light receiver is coupled to a drawing light source optical fiber via a second demultiplexing / multiplexing coupler. 6. The optical fiber gyro according to claim 4, wherein the first optical coupler and the optical fiber coil are connected via a third drawing optical fiber. An optical fiber gyro, wherein a phase modulator and an optical fiber coil are connected via a fourth stretching optical fiber. 7. An optical fiber gyro according to any one of claims 1 to 6, wherein a light source optical fiber for drawing, a modulation signal optical fiber for drawing, a third drawing optical fiber, or a fourth drawing optical fiber. An optical fiber gyro, wherein each of the drawing optical fibers has an optical connector.