JP2006319104A - Semiconductor ring laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ring laser apparatus wherein its smaller size, longer life-time, lower consumption power, and lower cost than conventional ones are intended, and its stable oscillation is realized by providing the apparatus wherein, as the laser luminous medium present in its ring resonator, no conventional external exciting light source and no conventional optical focusing lens system are required in addition to the miscellaneous advantages of a conventional SRL. <P>SOLUTION: With respect to the semiconductor ring laser apparatus, a semiconductor laser element having antireflection films applied to both its end surfaces is disposed in the optical path of a ring resonator constituted on a single substrate, and there is adopted the constitution wherein the driving power supply of the semiconductor laser element is so provided as to oscillate the laser element directly by the driving power supply. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state ring laser device, and more particularly to a ring laser gyro using the same, and more particularly to a semiconductor ring laser gyro suitable for use as an angular velocity / attitude angle sensor in attitude control and flight control systems of aircraft and rockets.

  Conventional ring laser devices can be roughly classified into a gas ring laser device (GRL) using He—Ne gas or the like as a laser emission medium and a solid ring laser device (SRL) using a solid laser element. Although GRL is currently in a practical stage, there are problems such as a large apparatus, a need for vacuum technology, a short life span, and high power consumption because high voltage is required for excitation. On the other hand, SRL is currently in the research and development stage, and has the advantages that it can be expected to reduce the size of the device, extend its service life, reduce power consumption, improve reliability, etc., but it excites the laser solid state element in the ring resonator. Therefore, an excitation light source such as a semiconductor laser or a lens system for condensing the excitation light on the solid element is required. In addition, the stability of the stimulated emission light source in the laser solid state element generated by absorbing the excitation light depends on the stability of the excitation light, and the stability of the induced emission light source affects the stability of the ring laser oscillation. Yes, the adjustment of the device is complicated. FIG. 5 is a schematic diagram of the SRL. In the figure, reference numeral 2 denotes a base, on which a ring resonator 1 constituted by two total reflection mirrors M1, M2 and a partial transmission mirror (output mirror) M3 to form a triangular closed loop optical path; The solid laser element 3a is located between the total reflection mirror M2 and the partial transmission mirror M3, the excitation light source 4a of the solid laser element is outside the triangular closed loop optical path, and the light from the excitation light source 4a is also outside the triangular closed loop optical path. The excitation light condensing lens system 5 for condensing the light on the solid laser element 3a via the total reflection mirror M1 is disposed, and power is supplied from an external power source 6 to the excitation light source 4a of the solid laser element. ing.

Therefore, in the conventional ring laser device, it is necessary to arrange an excitation light condensing lens system for condensing on the solid laser element, and in addition to the problem that the device becomes large, the lifespan, low power consumption, Realization of high reliability and cost reduction is difficult. In addition, the stability of the stimulated emission light source in the laser solid element generated by absorbing the excitation light depends on the stability of the excitation light, and the stability of the induced emission light source affects the stability of the ring laser oscillation. And adjustment of the apparatus is complicated.
In addition, the conventional ring laser device includes a resonator composed of three or more mirror surfaces as described above, a device composed of an optical fiber and an optical splitter (see Patent Document 1), an optical waveguide and a reflective surface. There is a component (see Patent Document 2).

The conventional ring laser gyro has the same problems as those of the ring laser apparatus described above. In other words, the optically pumped ring laser gyro (SRLG) is currently in the research and development stage and has advantages such as downsizing of the device, longer life, lower power consumption and improved reliability. In order to excite, an external light source such as a semiconductor laser or a light emitting diode is required. FIG. 6 is a schematic diagram of an “optically pumped ring laser gyro” disclosed in Patent Document 3 proposed by the present inventors. The laser excitation efficiency of the angular velocity detector can be increased, the size can be reduced, and even when installed in a harsh electromagnetic interference environment, it does not receive any electromagnetic interference and does not require electromagnetic interference treatment. The purpose is to obtain a ring laser gyro. In the figure, A is an angular velocity detector in which the ring resonator 1 and the optical angular velocity information reader 7 are arranged on the substrate 2, and B is an excitation light source / signal. An optical system constituting the processing unit, and C, an optical excitation energy / optical signal transmission unit including the excitation light source unit 10 and the signal processing unit 11. The ring resonator 1 includes a partially transmissive mirror M1 and total reflection mirrors M2 and M3. The mirror M3 is provided so that the solid laser element itself has a mirror function in the ring resonator 1. The optical angular velocity information reading device 7 includes total reflection mirrors M4 and M5 and a light beam interferometer BS. By configuring the angular velocity detection unit A and the optical excitation energy / optical signal transmission unit C with pure optical components, and connecting the angular velocity detection unit A with an excitation light source / signal processing unit B configured with an electric system via an optical fiber, It is electrically separated. However, in order to excite the laser solid state element in the ring resonator 1, the lens system FL causes the excitation light transmitted from the excitation light source unit 10 via the optical fiber to be condensed on the total reflection mirror / solid state laser element M3. Like the above-described ring laser device, an external excitation light source 10 such as a semiconductor laser or a light emitting diode driven by a power source 6 is required, and the device becomes complicated. In addition, the stability of the solid ring laser oscillation depends on the stability of the external light source that excites the solid element and the stability of the stimulated emission light source generated in the solid laser element, and this affects the output performance of the solid ring laser gyro. was there.
Japanese Patent Laid-Open No. 6-249750 “Optical Pulse Tester” published on September 9, 1994 JP 2002-350523 A "Magnetic Field Detection Device Using Semiconductor Ring Laser" Published on December 4, 2002 JP 2000-275048 “Optically Pumped Ring Laser Gyro” Published October 6, 2000

In addition to the advantages of the SRL described above, the present invention provides a device that does not require a conventional external excitation light source or a condensing lens system as a laser emission medium in the ring resonator, thereby further reducing the size of the device. Another object of the present invention is to provide a ring laser device that achieves stable oscillation while extending life, reducing power consumption, reducing costs, and the like.
In addition, by providing a device that does not require a conventional condensing lens system for external excitation light as a laser emitting medium in the ring resonator, further downsizing, extending the life, reducing power consumption, and cost of the device The aim is to improve the stability of the ring laser gyro device by reducing the frequency and realizing stable oscillation.

In the semiconductor ring laser device of the present invention, a semiconductor laser element having antireflection films on both end faces is disposed in a ring resonator formed on one base by two or more total reflection mirrors and a partial transmission mirror. In addition, a driving power source for the semiconductor laser element is provided.
According to another semiconductor ring laser device of the present invention, the ring resonator is composed of an optical fiber and an optical branching device, and a semiconductor laser element having antireflection films on both end faces is disposed in the ring resonator. An element driving power source is provided.

The semiconductor ring laser gyro of the present invention includes a semiconductor ring laser device including a semiconductor laser element having antireflection films on both end faces in a ring resonator, and an angular velocity from an optical signal output from the semiconductor ring laser device. An angular velocity detection unit is configured with an optical angular velocity information extraction device that extracts information, and the angular velocity is detected using the Sagnac effect of a ring laser.
The optical angular velocity information extraction device in the semiconductor ring laser gyro of the present invention includes two total reflection mirrors, two linear deflection elements (λ / 2 elements, λ: wavelength), a linear deflection beam combiner, and a non-deflection beam splitter. And two optical phase extractors (λ / 4 elements).
In addition to the angular velocity detector, the semiconductor ring laser gyro of the present invention includes an optical signal transmitter (optical fiber cord with two connectors) and an optical / electrical signal processor (two optical / electrical converters, two frequency counters and The signal processing unit is composed of an adder / subtractor) and a semiconductor laser driving power source.
In addition, the angular velocity detector of the semiconductor ring laser gyro according to the present invention is configured by assembling the above-described components on a single substrate.

The semiconductor ring laser device of the present invention is necessary for the solid ring laser by using a semiconductor laser element having a high antireflection film on both end faces instead of a conventional solid laser element as a laser emitting medium in a ring resonator. It is possible to omit the external excitation light source and the excitation light condensing lens system, which can further reduce the size, weight, power consumption, and material costs of the ring laser device. . In addition, since it can be manufactured in a solid state (all solid form) and no vacuum technology is required, the reliability is improved and the life is extended.
In addition, by directly driving the semiconductor laser element with the high antireflection film on both ends in the ring resonator, a stable stimulated emission light source can be produced and stable oscillation of the ring laser can be obtained.

The semiconductor ring laser gyro of the present invention uses a semiconductor laser element having antireflection films on both end faces as a laser emission medium in a ring resonator, and omits an external light source necessary for the solid ring laser, The gyro can be further reduced in size and weight, reduced in power consumption, reduced in material cost, and has great advantages as a gyro used in aircraft and the like. In addition, since it can be manufactured in a solid state and no vacuum technology is required, the reliability is improved and the life is extended.
In addition, by directly driving a semiconductor laser element with a high antireflection film at both ends in the ring resonator, a stable stimulated emission light source can be obtained, and a stable operation of the ring laser can be achieved by realizing a stable oscillation of the ring laser. .

The semiconductor ring laser device of the present invention uses a semiconductor laser element having a high antireflection film on both end faces instead of a conventional solid-state laser element as a laser emission medium in the ring resonator in the basic configuration of the SRL. Thus, the basic idea is to provide an apparatus that does not require a condensing lens system for external excitation light.
As one form for solving the above-described problems, the present invention includes a semiconductor laser element having a high antireflection film on both end faces in a ring resonator composed of three or more high reflection mirrors. By electrically operating the light, natural light is output from both end faces, and light emitted from one end face circulates in the ring resonator, enters the semiconductor element from the other end face, and passes through the light emitting portion. The semiconductor ring laser device that obtains the stimulated emission, and the light that circulates in the opposite direction similarly obtains the stimulated radiation. In FIG. 1, two total reflection mirrors M1 and M2 and one partial transmission mirror (output mirror) M3 constitute a ring resonator 1, and a semiconductor laser element 3 with a high antireflection film on both ends is formed. Arranged in the optical path between the two total reflection mirrors M1 and M2. All of these components are fixedly installed on the base 2 and the semiconductor laser element driving power source 8 is installed outside the base 2. The light propagating in the ring resonator 1 includes the clockwise CW and the counterclockwise light CCW. These lights are partially reflected by the transmission mirror M3 and partially transmitted to be transmitted outside the ring resonator 1. Is emitted.

  FIG. 2 shows an 8-shaped semiconductor ring laser device as another embodiment of the semiconductor ring laser device according to the present invention. The semiconductor laser device according to the present embodiment includes an 8-shaped ring resonator 1 on the substrate 2 that draws an 8-shaped optical path from three total reflectance mirrors M1, M2, M4 and a partially transmitting mirror (output mirror) M3. The semiconductor laser element 3 having a high antireflection film on both end faces is disposed inside thereof, the light emission axis thereof is made to coincide with the optical path axis of the resonator 1, and the semiconductor laser element 3 is operated by the drive power source 8. For example, light emitted from the left side of the semiconductor laser element circulates in the clockwise direction (CW) in the ring resonator 1, returns to the right end face, enters the semiconductor laser element from the end face, and passes through the light emitting portion. Oscillated CW induced radiation (CW laser light) is extracted to the outside via M3. Similarly, light emitted from the right end face circulates in the ring resonator in the counterclockwise direction (CCW), enters the semiconductor laser element from the left end face, oscillates by passing through the light emitting unit, and induces CCW induced radiation ( CCW laser light) is also taken out through M3.

  As shown schematically in FIG. 3, the semiconductor ring laser device according to the present invention comprises a ring resonator 1 on a substrate 2 composed of total reflectance mirrors M1, M2 and a partial transmission mirror (output mirror) M3. Inside, a semiconductor laser element (LD) 3 having a high antireflection film on both end faces is arranged, and its emission axis is made to coincide with the optical path axis in the resonator. A power supply 8 for driving the semiconductor laser element 3 is provided, and a semiconductor ring laser device 12 is configured. When the semiconductor laser element drive power supply 8 is turned on and operated, the light emitted from the left side of the semiconductor laser element 3 circulates in the clockwise direction (CW) in the ring resonator 1 and the semiconductor laser element 3 from the right end face. Resonating by entering inside and passing through the light emitting part, the CW light induced radiation (CW laser light) is extracted out of the ring resonator 1 through a partially transmitting mirror M3. Similarly, the light emitted from the right end face circulates in the ring resonator 1 counterclockwise (CCW), enters the semiconductor laser element from the left end face, resonates by passing through the light emitting part, and receives the CCW light. Stimulated radiation (CCW laser light) is extracted through a partially transmitting mirror M3. The two optical signals causing the Sagnac effect are electronically processed by the signal processing unit 11 via the optical angular velocity information extracting device 7 to output a frequency difference Δf between the two optical signals. This Δf is an amount proportional to the angular velocity Ω.

FIG. 4 shows an embodiment of a uniaxial semiconductor ring laser gyro employing the semiconductor ring laser device of the present invention. The gyro according to the present embodiment includes an angular velocity detection unit A, a signal processing unit 11 and a semiconductor laser element driving power source 8. The angular velocity detection unit A includes a semiconductor ring laser device 12 and an optical angular velocity information extraction measure 7. The semiconductor ring laser device 12 comprises a ring resonator 1 composed of total reflectance mirrors M1 and M2 and a partial transmission mirror (output mirror) M3, and a semiconductor laser element 3 having antireflection films applied to both end faces therein. If the semiconductor laser device 3 is arranged and configured and is operated by the drive power supply 8, ring laser oscillation can be realized.
The optical angular velocity information extracting device 7 includes two total reflection mirrors M4 and M5, two linear deflection elements (λ / 2 elements, λ: wavelength) P1, P2, linear deflection beam coupler PBS, and non-deflection beam splitter. It consists of NBS and two optical phase extractors (λ / 4 elements) PC1 and PC2. Its function is the output of the semiconductor ring laser device: CW light and CCW light are changed to M4 and M5, respectively, and the optical axis is changed to two linear deflection elements (λ / 2 elements) to make linearly polarized light p-wave and s-wave, respectively. The p-wave, in which the electrical vector of the CCW light is a linearly polarized light beam in the direction perpendicular to the paper surface, and the s-wave light beam, in which the electrical vector of the CW light is a linearly polarized light beam in a direction parallel to the paper surface, Then, the combined beam is bisected by the non-polarized beam splitter NBS and processed so that the relative phase is 90 degrees by the optical phase extractors (λ / 4 elements) PC1 and PC2, respectively. The optical signals N1 and N2 including angular velocity information proportional to the input angular velocity due to the Sagnac effect are output. This optical signal N1 is an optical pulse signal (corresponding to Δf) output from the optical angular velocity information extraction device, which is 45 degrees different from the phase of the p wave, and the optical signal N2 is optical angular velocity information extraction. This is an optical pulse signal of a synthesized wave that is output from the apparatus and is 135 degrees different from the phase of the p wave. N1-N2 indicates the polarity of angular velocity, that is, the direction of rotation, by> 0 or <0.

  The signal processing unit 11 is composed of an optical signal transmitter 13 and an optical / electrical signal processor 14, and converts the output signals N1 and N2 of the optical angular velocity information extracting device 7 into electric signals. Corresponding angular velocity information (size: N1 and polarity: N1-N2) is output. The optical signal transmitter 13 is composed of two optical fiber cords OF with connectors, and transmits the output signals N1 and N2 of the optical angular velocity information extracting device 7 to the optical / electrical signal processor 14 via the optical fiber cords OF. The optical / electrical signal processor 14 includes two optical / electrical converters, two frequency counters, and an adder / subtracter. The optical / electrical signal processor 14 converts N1 and N2 into electric signals, and adds / subtracts the magnitude of angular velocity information corresponding to the input angular velocity. And orientation information (polarity) is output.

The principle of angular velocity detection according to the present invention is based on the following equation.
Δf = (4A / Lλ) Ω
Δf: Beat frequency (N1) of output CW light and CCW light of semiconductor ring laser device
A: Area surrounded by the ring optical path of the ring resonator by the mirrors M1, M2, and M3 in FIG. 4 L: Ring optical path length λ: Ring laser oscillation wavelength Ω: Input angular velocity around the vertical axis of the A plane Therefore, this ring laser gyro is Ω can be obtained by measuring Δf.

It is a schematic diagram of the solid ring laser apparatus of this invention. It is a schematic diagram of the 8-shaped semiconductor ring laser device of the present invention. It is a schematic diagram of the semiconductor ring laser gyro of the present invention. It is a figure which shows the Example of the solid ring laser apparatus of this invention. It is a schematic diagram of the conventional solid ring laser apparatus. It is a schematic diagram of a conventional semiconductor ring laser gyro.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ring resonator 2 Base | substrate 3 Semiconductor laser element with both-ends high antireflection film 3a Solid-state laser element 4a Excitation light source of solid-state laser element 5 Excitation light condensing lens system (FL)
6 Power Supply 7 Optical Angular Velocity Information Extracting Device 8 Semiconductor Laser Element Drive Power Supply 11 Signal Processing Unit 12 Semiconductor Ring Laser Device 13 Optical Signal Transmitter 14 Optical / Electric Signal Processor A Angular Velocity Detection Unit B Excitation Light Source / Signal Processing Unit C Optical Excitation Energy / Optical signal transmission unit M1, M2, M3, M4, M5 Mirror CW Clockwise light CCW Counterclockwise light OF Optical fiber P1, P2 Linear deflector (λ / 2 element)
PBS Linear polarization beam combiner NBS Non-polarization beam splitter BS Beam interferometer Ω Input angular velocity PC1, PC2 Optical phase extractor (λ / 4 element)

Claims (6)

  A semiconductor laser element having antireflection films on both end faces is disposed in a ring resonator formed on one base by two or more total reflection mirrors and a partial transmission mirror, and a driving power source for the semiconductor laser element Semiconductor ring laser device with   A semiconductor ring laser device comprising a ring resonator composed of an optical fiber and an optical branching device, a semiconductor laser element having antireflection films applied to both end faces in the ring resonator, and a driving power source for the semiconductor laser element.   A semiconductor ring laser device including a semiconductor laser element having antireflection films on both end faces in a ring resonator, and an optical angular velocity information extraction device that extracts angular velocity information from an optical signal output from the semiconductor ring laser device; A semiconductor ring laser gyro that comprises an angular velocity detector and detects the magnitude and polarity of the angular velocity using the Sagnac effect of the ring laser.    The optical angular velocity information extraction device includes two linearly polarizing elements (λ / 2 elements), a linearly deflected beam coupler, a non-deflected beam splitter, and two optical phase extractors (λ / 4 elements). The CW light and CCW light, which are the outputs of the semiconductor ring laser device, are converted into linearly polarized light p-waves and s-waves by the two linear deflection elements, respectively, and these are converted into p-waves and s-waves by the linear deflection light beam coupler. The light is combined with the light, and the combined light is further divided into two by the unpolarized light splitter, and each of them is processed by the optical phase extractor so that the relative phase becomes 90 degrees, and by the Sagnac effect of the ring laser 4. The semiconductor ring laser gyro according to claim 3, which outputs an optical signal including angular velocity information proportional to the input angular velocity.   The signal processing unit includes an optical signal transmitter and an optical / electrical signal processor, and the optical / electrical signal processor outputs electric signals N1 and N2 of the optical angular velocity information extracting device as electric signals. The semiconductor ring laser gyro according to claim 3 or 4, wherein the magnitude and polarity of the input angular velocity information are output by addition / subtraction processing.   6. The semiconductor ring laser gyro according to claim 3, wherein the angular velocity detection unit is configured by assembling the component parts on a single substrate.

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