阅读说明：本技术 在玻璃状主体中使用稀土增益掺杂剂的固态环形激光陀螺仪 (Solid-state ring laser gyroscope using rare earth gain dopants in a glassy body ) 是由 迪安·E·约翰逊 吴剑峰 艾伦·布鲁斯·塔弛贝里 特里萨·马尔塔 于 2019-07-19 设计创作，主要内容包括：本发明题为“在玻璃状主体中使用稀土增益掺杂剂的固态环形激光陀螺仪”。本发明提供了一种固态环形激光陀螺仪,该固态环形激光陀螺仪包括：激光器块,所述激光器块包括具有光学闭环路径的谐振环腔；多个反射镜结构,安装在该块上并包括反射闭环路径周围的光束相应的多层反射镜；和泵浦激光器组件,该泵浦激光器组件通过反射镜结构中的一个反射镜结构与闭环路径光学通信。多层反射镜的一个或多个包含稀土掺杂增益层,该稀土掺杂增益层可操作以在闭环路径中产生反向传播光束的双向光学放大。在一些实施方案中,该增益层包含掺杂到玻璃状主体材料中的除钕之外的稀土掺杂剂,该玻璃状主体材料包含二氧化钛、氧化钽、氧化铝、氧化锆、硅酸盐玻璃、磷酸盐玻璃、亚碲酸盐玻璃、氟硅酸盐玻璃或非氧化物玻璃。另选地,该增益层除二氧化硅之外可包含掺杂到玻璃状主体材料中的钕掺杂剂。(The invention provides a solid-state ring laser gyroscope using rare earth gain dopants in a glassy body. The present invention provides a solid-state ring laser gyroscope, comprising: a laser block comprising a resonant ring cavity having an optical closed-loop path; a plurality of mirror structures mounted on the block and including respective multilayer mirrors that reflect the light beam around the closed loop path; and a pump laser assembly in optical communication with the closed loop path through one of the mirror structures. One or more of the multilayer mirrors includes a rare earth doped gain layer operable to produce bidirectional optical amplification of a counter-propagating beam in a closed-loop path. In some embodiments, the gain layer comprises a rare earth dopant other than neodymium doped into a glassy host material comprising titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass. Alternatively, the gain layer may contain neodymium dopants doped into the glassy host material in addition to silicon dioxide.)

1. A solid-state ring laser gyroscope comprising:

a laser block comprising a resonant ring cavity having an optical closed-loop path;

a plurality of mirror structures respectively mounted on the laser block, each of the mirror structures comprising a respective multilayer mirror in optical communication with the optical closed-loop path, each multilayer mirror positioned and angled to reflect light beams around the optical closed-loop path; and

a pump laser assembly in optical communication with the optical closed-loop path through one of the mirror structures;

wherein one or more of the multilayer mirrors include a rare earth doped gain layer operable to produce bidirectional optical amplification of a counter-propagating beam in the optical closed-loop path;

wherein the pump laser assembly is configured to inject a beam into the rare earth doped gain layer;

wherein the rare earth doped gain layer comprises:

a rare earth dopant other than neodymium doped into a glassy host material, wherein the glassy host material comprises titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass; or

A neodymium dopant other than silicon dioxide doped into the glassy host material.

2. The ring laser gyroscope of claim 1, wherein:

the rare earth dopant comprises cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium; or

When the rare earth doped gain layer comprises a neodymium dopant other than silicon dioxide doped into a glassy host material, the glassy host material comprises titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass.

3. A gain mirror structure comprising:

a substrate;

a multilayer mirror stack on the substrate; and

a rare earth doped gain layer on the multilayer mirror stack, wherein the rare earth doped gain layer comprises:

a rare earth dopant other than neodymium doped into a glassy host material, wherein the glassy host material comprises titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass; or

A neodymium dopant other than silicon dioxide doped into the glassy host material;

wherein the gain mirror is operable to produce bidirectional optical amplification of the counter-propagating light beam in the optical closed-loop path.

Background

Ring laser gyroscopes typically comprise a block of solid dielectric material having a plurality of interconnected channels arranged in a closed loop to form a resonant cavity with mirrors located at the intersection of each channel. In some embodiments, a lasing gas is contained within the resonant cavity and an electrical potential is applied to the lasing gas to produce a counter-propagating laser beam in the resonant cavity. In other embodiments, a solid state gain medium is added to one of the mirrors in the resonant cavity to produce a counter-propagating laser beam, without the use of a laser gas. For example, several half-wavelengths of neodymium-doped silicon dioxide may be used to create a laser gain medium for a resonant cavity.

Disclosure of Invention

A solid-state ring laser gyroscope comprising: a laser block comprising a resonant ring cavity having an optical closed-loop path; a plurality of mirror structures respectively mounted on the laser block, each of the mirror structures comprising a respective multilayer mirror in optical communication with the optical closed-loop path, each multilayer mirror positioned and angled to reflect a beam around the optical closed-loop path; and a pump laser assembly in optical communication with the closed loop path through one of the mirror structures. One or more of the multilayer mirrors includes a rare earth doped gain layer. The gain layer is operable to produce bidirectional optical amplification of the counter-propagating light beam in the optical closed-loop path. The pump laser assembly is configured to inject a beam into the rare earth doped gain layer. In some embodiments, the rare earth doped gain layer comprises a rare earth dopant other than neodymium doped into a glassy host material comprising titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass. Alternatively, the rare earth doped gain layer may include or be doped into a neodymium dopant other than silicon dioxide in the glassy host material.

Drawings

Features of the present invention will become apparent to those skilled in the art from the following description with reference to the accompanying drawings. Understanding that the drawings depict only typical embodiments and are not therefore to be considered to be limiting of the invention's scope, the invention will be described with additional specificity and detail through the use of the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a solid-state ring laser gyroscope that may be implemented with rare-earth gain-doped materials, according to one embodiment; and

FIG. 2 is a schematic diagram of a gain mirror structure that may be used for bi-directional optical amplification in a solid-state ring laser gyroscope, according to one embodiment.

Detailed Description

In the following detailed description, embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense.

A solid-state ring laser gyroscope using rare earth gain dopants in a glassy body is disclosed.

As described above, neodymium (Nd) -doped silicon dioxide (SiO) is known₂) Can be used for generating a laser gain medium for a resonant cavity of a solid-state ring laser gyroscope. While such laser gain media have been well studied, other active gain dopants can be selected to achieve the same purpose, as well as other glassy bodies for active gain dopants.

In some embodiments, rare earths doped with active gain media other than neodymium-doped silicon dioxide may be used as solid state gain media. In some embodiments, the gain medium may comprise neodymium doped into a glass matrix other than silicon dioxide, such as a glass matrix suitable for ion beam sputter deposition.

The laser gain medium may be fabricated as a thin film gain mirror that provides bi-directional optical amplification of a beam in the resonator of the ring laser gyroscope. When the gain in the optical closed-loop path of the resonator exceeds the loss, two counter-propagating beams travel around the path and can be used to measure rotation.

A thin film gain mirror can be constructed by first depositing alternating layers of dielectric material onto a highly polished substrate to form a multilayer dielectric mirror. Thereafter, a single layer of rare earth doped glassy host material is deposited on top of the multi-layer dielectric mirror to form a gain mirror. In various embodiments, the dielectric mirror may be tuned to the laser beam wavelength by making the thickness of the alternating layers of dielectric material equal to one-quarter of the optical wavelength of the counter-propagating laser beam. The thickness of the gain mirror may be an integer of half the optical wavelength of the laser beam in order to maximize the laser intensity within the gain layer for maximum gain.

The rare earth ions in the glassy host material of the gain mirror are responsible for the optical amplification of the beam. The frequency of the beam is sensitive to rotation, and beam combining optics and detectors can be used to measure the difference in beam frequency proportional to rotation.

The present solid-state ring laser gyroscope has the benefit of eliminating the wear mechanism typically found in ring laser gyroscopes that contain a lasing gas in the resonant cavity, and is less costly to manufacture.

Further details of various embodiments are described below in conjunction with the figures.

FIG. 1 illustrates a solid-state ring laser gyroscope 100 that may be implemented with rare-earth gain-doped materials, according to one embodiment. The ring laser gyroscope 100 includes a laser block 110 having a resonant ring cavity in the form of an optical closed-loop path 112 having a substantially triangular shape. While the embodiment of fig. 1 shows the laser block 110 as a triangle with three obtuse angles, it should be understood that this is a non-limiting example and other embodiments may include laser blocks having different shapes.

A plurality of mirror structures 114, 116 and 118 are mounted on the laser block 110 at each of the respective corners 115, 117 and 119. Each of the mirror structures 114, 116 and 118 has a respective highly reflective multilayer mirror 120, 122 and 124 positioned at the intersection of the channels in the closed-loop path 112 and angled appropriately to reflect light from one channel into another channel. In one embodiment, multilayer mirrors 120, 122, and 124 are multilayer dielectric mirrors.

At least one of the multilayer mirrors is formed as a thin film gain mirror comprising a rare earth doped gain medium, the gain mirror operable to produce bidirectional optical amplification in the closed loop path 112. For example, a rare earth doped gain layer 128 may be formed on the multilayer mirror 120 to produce a gain mirror, as shown in FIG. 1. In other embodiments, rare earth doped gain layers may be formed on one or more other multilayer mirror structures 122, 124. The gain layer may be formed from a thin amorphous film of rare earth doped glass material that may be deposited on the multilayer mirror using conventional deposition techniques. Further details of the gain mirror structure and composition are described below with reference to fig. 2.

A pump laser assembly 130 including a light source 132 and focusing optics 134 is in optical communication with the closed loop path 112 through the mirror structure 114. For example, the light source 132 may include a laser diode, a Light Emitting Diode (LED), a superluminescent LED, or an LED array.

A readout device 140 including one or more photodetectors 142 is in optical communication with the closed-loop path 112 via the mirror structure 116. The processing unit 150 is in operable communication with the readout device 140.

When a beam is injected into the rare earth doped gain layer 128 by the pump laser assembly 130, the injected beam needs to be emitted at a specific wavelength or wavelengths that are absorptive to the gain layer 128 in order to provide excitation energy to achieve population inversion to sustain lasing. This causes a pair of counter-propagating beams 160 within the closed-loop path 112 to travel along the same optical path by reflecting from the multilayer mirrors 120, 122, and 124.

Rotation of ring laser gyroscope 100 causes the effective path length of counter-propagating beam 160 to change, thereby creating a frequency difference between the two beams, which can be used to determine angular rate. For example, when optical signal information is coupled from the closed-loop path 112 to the readout device 140, the output of the voltage signal is sent through the readout device 140 to the processing unit 150. The frequency difference between the counter-propagating beams 160 is determined from the voltage signal and thus rotation information can be obtained.

Other details not shown regarding the physical structure and electronic circuitry associated with the laser block of the ring laser gyroscope are considered to be within the knowledge of one of ordinary skill in the art and therefore will not be described herein.

Fig. 2 illustrates a gain mirror structure 200 according to one embodiment that may be used for bi-directional optical amplification, such as in a solid-state ring laser gyroscope. The gain mirror structure 200 includes a substrate 210, such as a highly polished glass substrate. A multilayer mirror stack 220, such as a high reflectivity multilayer dielectric mirror, is formed on substrate 210. Multilayer mirror stack 220 may be formed by depositing alternating layers of higher and lower index materials, each having a thickness of, for example, one-quarter of the optical wavelength. In one embodiment, alternating titanium dioxide (TiO) may be deposited by standard thin film deposition techniques₂) And a silicon dioxide layer to form a multilayer mirror stack 220.

A rare earth doped gain layer 230 is formed on the multilayer mirror stack 220. The gain layer 230 may be formed by depositing a thin film of rare earth doped glassy host material onto the outer layers of the multilayer mirror stack 220. In one embodiment, the thickness of the gain layer 230 is formed to be, for example, an integer number of half optical wavelengths. For example, an ion beam sputter deposition process may be employed to form the gain layer 230.

Non-limiting examples of suitable rare earth dopants that may be used to form gain layer 230 include cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Y)b) And lutetium (Lu). Non-limiting examples of glassy host materials that may be used to form gain layer 230 include silicon dioxide, titanium dioxide, tantalum oxide (Ta)₂O₅) Alumina (Al)₂O₃) Zirconium oxide (ZrO)₂) Silicate glass, phosphate glass, fluorosilicate glass, non-oxide glass such as fluoride glass, and the like. Other glassy host materials suitable for ion beam sputter deposition may also be used.

In some embodiments, neodymium is doped into other glassy host materials in addition to silicon dioxide to form a gain layer. For example, neodymium may be doped into other glassy host materials, such as titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass, such as fluoride glass.

In some other embodiments, rare earth dopants other than neodymium are doped into the glassy host material to form the gain layer. For example, rare earth dopants other than neodymium may be doped into titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass, such as fluoride glass.

Exemplary embodiments