JP2007212247A - Optical fiber type ring laser gyro - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive ring laser gyro by using a rare earth element doped fiber. <P>SOLUTION: This optical fiber type ring laser gyro has a constitution comprising a sensing part 1 comprising the rare earth element doped fiber, an excitation light introduction part 5 having a light source 4 for excitation on the sensing part 1, and a detection part 16 having a light receiving element 15 and a light source 13 for detection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical fiber type ring laser gyro, and in particular, a pair of couplers is provided in a sensing unit made of a rare earth element-doped fiber formed in a loop shape, an excitation light source is connected to one coupler, and the other coupler is connected to The present invention relates to a completely new ring laser gyro which connects a detection light source and a light receiving element and constitutes a ring laser gyro by laser oscillation utilizing the amplification effect of a rare earth doped fiber.

  As this type of ring laser gyro used heretofore, as disclosed in Non-Patent Document 1, a narrow hole is formed in a cavity using low thermal expansion glass processed to have a triangular or quadrangular space. A high-performance mirror with high reflectivity and low turbulence is provided at each apex of this cavity, and a well-known induction based on discharge by applying high voltage by enclosing a mixed gas of helium and neon in this cavity A typical method is to detect the input angular velocity from the interference output using the well-known Sagnac effect by emitting light and oscillating lasers in both directions.

The second edition of “Modern Internal Technology (by Anthony Law-rence)” published in 1998, p208-224 (Ring Laser Gyro).

Since the conventional ring laser gyro is configured as described above, the following problems exist.
In other words, low thermal expansion glass materials for forming triangular or quadrangular glass cavities are expensive, and the processing and processing of high performance prisms and mirrors and the manufacture of special electrodes are very costly, and laser A large amount of cost is required for mirror alignment for forming the resonator, He—Ne gas sealing inside, joining of the component to the cavity, and the like, and it has been impossible to produce a low-cost product with a simple configuration.

  An optical fiber type ring laser gyro according to the present invention includes a sensing unit in which both end faces of a rare earth doped fiber are fusion-bonded to form a loop, a first coupler provided in contact with an outer periphery of the sensing unit, and the first coupler An excitation light introducing unit comprising an excitation light source provided at one end of the sensor, a second coupler provided in contact with the outer periphery of the sensing unit, a light receiving element and a detection light source provided at both ends of the second coupler, And detecting light from the light source for detection and pumping light from the light source for excitation are input to the sensing unit, and stimulated emission in the sensing unit due to the amplification effect of the rare earth doped fiber The left and right lasers are generated in the sensing unit, the return light from the detection unit is detected by the light receiving element, and the input angular velocity is detected. And the first coupler, the third coupler provided between the first coupler and the excitation light source, the second coupler, the second coupler, the detection light source, and the light receiving element. The pumping light and the detection light can be introduced into the sensing unit in the CW and CCW directions by four couplers each including a fourth coupler provided therebetween.

Since the optical fiber ring laser gyro according to the present invention is configured as described above, the following effects can be obtained.
In other words, a pair of couplers are provided in a sensing section made of a rare earth element-doped fiber formed in a loop shape, an excitation light source is connected to one coupler, a detection light source and a light receiving element are connected to the other coupler, and a rare earth doped Since the ring laser gyro is obtained by laser oscillation utilizing the amplification effect of the fiber, the structure is simpler than the conventional one and the cost can be reduced.

  In the present invention, a pair of couplers are provided in a sensing unit made of a rare earth element-doped fiber formed in a loop shape, an excitation light source is connected to one coupler, a detection light source and a light receiving element are connected to the other coupler, An object of the present invention is to provide an optical fiber type ring laser gyro in which a very simple configuration using low-cost parts made of optical fibers is a low-cost configuration.

A preferred embodiment of an optical fiber type ring laser gyro according to the present invention will be described below with reference to the drawings.
In FIG. 1, a reference numeral 1 denotes a sensing unit made of a rare earth doped fiber and having a loop shape by fusion-bonding both end faces 1 a and 1 b, and an optical fiber provided in contact with the outer periphery of the sensing unit 1. A first coupler 2 is provided.

  The first coupler 2 is connected to an excitation light source 4 via a third coupler 3, and an excitation light introducing unit 5 is configured by the first coupler 2, the third coupler 3, and the excitation light source 4.

  A second coupler 10 made of an optical fiber is provided on the outer circumference of the sensing unit 1 so as to face the first coupler 2, that is, along the diameter direction of the sensing unit 1, and both ends of the second coupler 10. Are provided with a detection light source 13 for generating detection light 12 via a fourth coupler 11 and a light receiving element 15 for receiving the return light 14.

  The first to fourth couplers 2, 3, 10, and 11 are composed of -3 dB couplers, the light sources 4 and 13 are each composed of a laser, and the light receiving element 15 is composed of a photodiode or the like. Accordingly, the second and fourth couplers 10 and 11, the detection light source 13 and the light receiving element 15 constitute a detection unit 16.

In the above-described configuration, the pumping light 4 a having an appropriate wavelength is supplied from the pumping light source 4 to the sensing unit 1 through the first and third couplers 2 and 3 according to the type of the rare earth doped fiber of the sensing unit 1.
In this case, two couplers 2 and 3 are used in the sensing unit 1 in order to distribute light of equal intensity around the left and right.

Next, detection light 12 having an appropriate wavelength according to the type of the sensing unit 1 is input to the sensing unit 1 via the fourth and second couplers 11 and 10.
Under the above-described state, the detection light 12 causes a well-known stimulated emission in the sensing unit 1, and the lasers in both the left and right directions oscillate.
Since the return light 14 of the detection unit 16 is the interference light, the return light 14 is received by the light receiving element 15.

By detecting the return light 14 by the light receiving element 15, the input angular velocity can be obtained from the interference fringe change accompanying the rotation.
Therefore, in the present invention, the stimulated emission required for the laser oscillation of the ring laser gyro can be performed by a simple optical system that combines a commercially available rare earth element-doped fiber, a light source, and a light receiving element, which is expensive in the past. Parts are not required.

  According to the present invention, an optical fiber type ring laser gyro with a simpler structure and lower cost can be realized by selecting the kind of rare earth doped fiber.

It is a block diagram which shows the optical fiber type ring laser gyro by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensing part 2 1st coupler 1a, 1b End surface 2, 3 1st, 3rd coupler 4 Excitation light source 5 Excitation light introduction part 10, 11 2nd, 4th coupler 12 Detection light 13 Detection light source 14 Return light 15 Light receiving element

Claims (2)

A sensing part (1) in which both end faces (1a, 1b) of the rare earth doped fiber are fused and joined to form a loop, a first coupler (2) provided in contact with the outer periphery of the sensing part (1), and the above-mentioned An excitation light introducing part (5) comprising an excitation light source (4) provided at one end of the first coupler (2), and a second coupler (10) provided in contact with the outer periphery of the sensing part (1) And a detector (16) comprising a light receiving element (15) and a light source for detection (13) provided at both ends of the second coupler (10),
Under the condition that the detection light (12) from the detection light source (13) and the excitation light (4a) from the excitation light source (4) are input to the sensing unit (1), the amplification effect of the rare earth doped fiber Causes stimulated emission in the sensing unit (1), lasers in both the left and right directions are generated in the sensing unit, and the return light (14) from the detection unit (16) is detected by the light receiving element (15). An optical fiber type ring laser gyro characterized by detecting an input angular velocity.   A third coupler (3) provided between the first coupler (2) and the first coupler (2) and the excitation light source (4); the second coupler (10); and the second coupler. And the fourth coupler (11) provided between the light source for detection (13) and the light receiving element (15), and the four couplers (2, 3.10, 11) comprising The optical fiber type ring laser gyro according to claim 1, wherein both the light (4a) and the detection light (12) can be introduced into the sensing unit (1) in the CW and CCW directions.

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