JPH0493716A - Optical fiber gyroscope - Google Patents

Abstract

PURPOSE:To make it possible to achieve simplification and compact configuration for the constitution of an optical fiber gyroscope by providing one optical switch which is connected to one light source and a plurality of photodetectors which are connected to a plurality of optical fiber loops. CONSTITUTION:The light emitted from one light source 1 is selectively cast into a first optical coupler - a third optical coupler 7 - 9 by time division processing. The light beams from the couplers 7 - 9 are modified in a first modulator - a third modulator 19 - 21. The light beams are cast into a first optical fiber loop - a third optical fiber loop 25 - 27 and circulated. When an angular velocity input from the outside is generated in any of the optical fiber loops 25 - 27 under this state, the angular velocity input is detected as the intense and weak signals of the light by the interference based on a Sagnac effect in any of the a first photodetector - a third photodetector 13 - 15. The angular velocity input can be detected. Namely, since the light source is commonly used, the stable control of only one light source is sufficient. The constitution of electronic circuits and the optical system can be simplified, and the compact, low-cost constitution can be obtained.

Description

Detailed Description of the Invention: a. Field of Industrial Application The present invention relates to an optical fiber gyro, and in particular, to a method for supplying light to a plurality of optical fiber gyros using only one light source and for downsizing with a simple configuration. Concerning new improvements.

b. Conventional technology There are various optical fiber gyros of this type that have been used in the past, but among them, the most common one is the elliptical configuration, although the name of the literature disclosing its configuration is not listed here. When optical fiber loops are used, a light source and a photodetector are provided corresponding to each optical fiber loop.

C1 Problems to be Solved by the Invention Since the conventional optical fiber gyro was configured as described above, the following problems existed.

Generally, in order to maintain the characteristics of an optical fiber gyro constant over a wide temperature range, structural members with a coefficient of thermal expansion similar to that of optical fibers are used to prevent distortion and stress from being applied to optical systems such as optical fibers due to temperature changes. Alternatively, the temperature of the optical fiber gyro is usually adjusted using a heater, a cooling element, etc. so that the temperature change applied to the optical fiber gyro is as small as possible.

Among them, the characteristics of the light source in particular vary significantly due to temperature changes, and in order to realize a high-performance fiber optic gyro, it is necessary to keep the light intensity of the light source constant. ! It was necessary to detect the temperature with a detector and adjust the current applied to the light source.

Therefore, as in the past, it is necessary to make the light intensities of the plurality of light sources corresponding to the plurality of optical fiber loops all the same, which requires an increase in the number of various compensation circuits and an increase in the number of optical fibers. ), the shape became larger and the current consumption inevitably increased, which became a major obstacle to miniaturization.

The present invention has been made to solve the above-mentioned problems, and in particular, an optical fiber that supplies light to a plurality of optical fiber gyros using only one light source and is miniaturized with a simple configuration. The purpose is to provide gyro.

d. Means for Solving the Problems The optical fiber gyro according to the present invention supplies light emitted from a light source to a plurality of optical fiber loops, and detects the light that has passed through each of the optical fiber loops as a difference between strong and weak signals of the light and detects the difference between the light and the weak signals. In the optical fiber gyro which detects angular velocity input by detecting the angular velocity input, there is only one light source, and a 1g optical switch is connected to the light source, and a 1g optical fiber loop is connected to the optical fiber loop. This configuration includes a plurality of photodetectors.

In addition, the optical fiber gyro, which was invented by Ike, supplies light emitted from a light source to multiple optical fiber loops.
In the optical fiber gyro, the angular velocity input is detected by detecting the light passing through each of the optical fiber loops with a photodetector as a difference between the intensity signals of the light, and the number of the light source is only one, and the light source is connected to the light source. This configuration includes one optical switch and one photodetector connected to the optical switch.

01 Effect In the optical fiber gyro according to the present invention, the light emitted from one light source is selectively split into three lights via an optical switch, and the split customer can selectively send the light to each optical fiber loop. It is incident.

In addition, the detection light from each optical fiber loop is input to each photodetector by the selection operation of the optical switch, and the light intensity increases.
It is detected as an i signal.

Therefore, if there are only a few optical fiber loops (angular velocity inputs) among each optical fiber loop, each photodetector detects the intensity signals of the light from the optical fiber loops corresponding to the angular velocity inputs. It is possible to detect angular velocity input in the axial direction.

In another aspect of the invention in which the photodetector is configured with one photodetector, the detection light from each optical fiber loop is sequentially detected by the photodetector through time-division processing using an optical switch.

f. Embodiment Hereinafter, a preferred embodiment of the optical fiber gyro according to the present invention will be described with reference to the drawings.

1 and 2 show an optical fiber gyro according to the present invention. FIG. 1 is a block diagram showing a first embodiment, and FIG. 2 is a block diagram showing a second embodiment.

In FIG. 1, the reference numeral l is a light source that emits laser light, and this light source 1 transmits light through a first optical fiber 2...! This optical switch 3
The second. The first... via the third and fourth optical fibers 4.5.6. It is connected to the second and third optical couplers 7.8.9.

Each optical coupler 7.8.9 has a fifth. First, second and third photodetectors 13.14.15 are connected via sixth and seventh optical fibers 10.11.12.

Each optical coupler 7.8.9 is the 8th. Ninth and tenth optical fibers 16. ], 7.18 through 1st ° 2nd and 3rd
The modulators 19.20.21 are connected to a multi-rotation ring-shaped first
．． Connected to second and third optical fiber loops 25, 26, 27, respectively.

Note that the geometrical axes of the loops 25 to 27 are arranged to be perpendicular to each other.

In the above configuration, the light emitted from one light source 1 is selectively input to each of the coverlets 7, 8, and 9 by time-sharing processing.

The light from each coupler 7.8.9 is transmitted to each modulator 19 2
Each optical fiber loop 25 26
．． 27 and circulates.

In the above-mentioned state, if an angular velocity input occurs from the outside to any of the optical fiber loops 25 to 27 arranged in the axial direction, one of the photodetectors 13 to 15, It is detected as a light intensity signal due to interference based on the well-known Sakuna-Iri effect, and it is possible to detect an angular velocity input.

In addition, in the configuration shown in FIG. 2, the same parts as those in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted, and only the parts different from FIG. 1 will be explained.

That is, although the optical switch 3 consists of one structure, the first
It is composed of a switch section 3A and a second switch section 3B, and this first switch section 3A has one modulator for each, 20.2
1 via each optical fiber 4.56, and the second switch section 3B is connected to each optical fiber 10.11.
12 to each of said modulators 19, 20, 21.

One photodetector 30 is connected to the second switch section 3B, and the detection light from each optical fiber loop 25, 26, 27 is modulated by time division processing of the second switch section 3B. 19, 20, and 21 in a time-division manner.

The time-division operation of the optical switch 3 is configured to switch the optical signal from the light source 1 to each optical fiber loop 25.2627 once by time-division processing based on the pattern shown in FIG. , for example, in the case of Figure 2,
Based on the elapse of time t, if t1≦1<12, the light is allowed to enter the third optical fiber loop 27, and the detection signal at the photodetector 30 is processed as Z-axis data.

Also, t2≦1<1. In the relationship, t3≦1<1. In this relationship, it is similarly processed as X-axis data.

Further, in the above-mentioned embodiments, the case of three axes has been described, but similar effects can be obtained even when changing to two axes, four axes, etc.

g. Effects of the Invention Since the optical fiber harness according to the present invention is constructed as described above, it is possible to obtain the following effects.

That is, since one common light source is used, only the 1g light source needs to be stably controlled, the electronic UjiJ path configuration and the optical system configuration can be greatly simplified, and a compact and inexpensive configuration can be obtained. I can do it.

In addition, since there is only one light source, the current consumption is low, and it is possible to obtain the effect that the current consumption is only required by the conventional shaft-end fiber gyro.

[Brief explanation of drawings]

1 to 31 are for showing the optical fiber gyro according to the present invention, FIG. 1 is a block diagram showing the first embodiment, FIG. 2 is a block diagram showing the second embodiment, and FIG. 3 is a block diagram showing the second embodiment. FIG. 2 is a pattern diagram showing time-division processing of an optical switch. 1 is a light source, 3 is an optical switch,] 3.14 15 is a photodetector, 25.26.27 is an optical fiber loop, and 30 is a photodetector.

Claims (2)

[Claims] (1) The light emitted from the light source (1) is supplied to a plurality of optical fiber loops (25, 26, 27), and the light that has passed through each optical fiber loop (25, 26, 27) is By detecting the difference with a photodetector,
In an optical fiber gyro configured to detect angular velocity input, there is only one light source (1), one optical switch (3) connected to the light source (1), and each of the optical fiber loops (25, 26). , 27), each of the optical fiber loops (25) is
, 26, 27) and the detection light to be incident on each of the detectors (13, 14, 15). (2) The light emitted from the light source (1) is supplied to a plurality of optical fiber loops (25, 26, 27), and the light that has passed through each optical fiber loop (25, 26, 27) is By detecting the difference with a photodetector,
An optical fiber gyro configured to detect angular velocity input includes only one light source (1), one optical switch (3) connected to the light source (1), and one optical switch (3) connected to the light source (1).
), and the operation of the optical switch (3) selectively injects light into each of the optical fiber loops (25, 26, 27) and detects the detected light. An optical fiber gyro, characterized in that the light incident on the photodetector (30) is selected.