Laser and communication device
By using a combination technology of collimating lenses and confocal optical cavity in the laser, the laser line width is optimized and miniaturized, solving the problems of existing laser line width and miniaturization.
Patent Information
- Application Number
- CN202311344407.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-16
- Publication Date
- 2025-04-18
AI Technical Summary
While existing lasers achieve narrow line widths, it is difficult to miniaturize, and the intrinsic frequency noise of semiconductor lasers is relatively high, affecting line width performance.
A collimating lens is used to convert the laser light of the light source into a collimating beam, and reflect it multiple times through the confocal optical cavity to form a feedback beam injected into the light source, realizing laser linewidth compression. At the same time, the phase of the feedback light beam is adjusted by the phase modulation unit to ensure the self-injection locking condition.
The laser line width optimization and miniaturization design are achieved, reducing packaging difficulty and cost, while improving the manufacturing and mass production of the device.
Smart Images
Figure CN119852824A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the field of laser technology, and in particular to a laser and a communication device. Background Art
[0002] Lasers have a stable spectrum. Compared with ordinary light sources, lasers have superior coherence and monochromaticity and are widely used in different fields such as communications and construction. In order to meet the needs of inter-city and space laser coherent communications with further improved performance in the future, frequency modulated continuous wave laser radar for artificial intelligence environment perception, space gravity detection, atomic and molecular measurement, etc., higher requirements are also placed on the line width, volume power consumption, production cost, etc. of lasers.
[0003] An important parameter of a laser is the line width. Currently, narrow line width lasers include solid narrow line width lasers, fiber narrow line width lasers, and semiconductor narrow line width lasers. Among them, the line width of solid and fiber narrow line width lasers can reach 100-kHz level, but they are large in size, cover limited wavelengths, have high production costs, and stagnate in performance. Semiconductor lasers can be mass-produced at low cost, are small in size, have low power consumption, and cover a wide range of wavelengths, and are widely favored.
[0004] However, the intrinsic frequency noise of semiconductor lasers is relatively large, and the best distributed feedback (DFB) lasers are also in the hundreds of kHz level. In order to solve this problem, the Confocal Fabry-Perot (CFP) cavity is used to narrow the laser line width by self-injection feedback. The laser can be focused by a lens and then incident on the Confocal Fabry-Perot resonant cavity.
[0005] However, the laser emission divergence angle is much smaller than the optical cavity mode divergence angle, which makes the lens image distance much larger than the object distance, and the optical path is elongated, making it difficult to miniaturize. Summary of the invention
[0006] The embodiments of the present application provide a laser and a communication device to optimize the line width performance of the laser and achieve miniaturization of the device.
[0007] In order to achieve the above objectives, this application adopts the following technical solutions:
[0008] In the first aspect of the present application, a laser is provided, comprising: a light source, a collimating lens and a confocal optical cavity, wherein the collimating lens is located between the light source and the confocal optical cavity; the light source is used to generate laser light, and the collimating lens is used to convert the laser light of the light source into collimated light; the optical axis of the collimating lens is parallel to the optical axis of the confocal optical cavity; the confocal optical cavity is used to receive the collimated light, and after multiple reflections of the collimated light, part of the reflected light forms a feedback beam and is injected into the light source. Thus, the light source can output a collimated light beam to the confocal optical cavity through the collimating lens, and the confocal optical cavity is used to feed the collimated light beam back to the light source after internal reflection to form a feedback optical path, thereby achieving laser line width compression. A collimated light beam is used instead of a convergent light beam, and the optical path is shortened. In addition, under the action of the collimating lens, the collimated light beam is incident on the confocal optical cavity along the optical axis. Compared with the laser incident at an angle deviating from the optical axis of the confocal optical cavity, it is easier to align and reduces the difficulty of packaging. It can be packaged into the packaging tube shell commonly used in the optical communication industry, while reducing the packaging cost and coupling difficulty of the device, and improving the manufacturability and mass production of the device.
[0009] In an optional implementation, the laser further includes: a phase modulation unit, the phase modulation unit is arranged between the collimating lens and the confocal optical cavity, the feedback light beam is injected into the light source through the phase modulation unit, and the phase modulation unit is used to phase modulate the feedback light beam so that the phase of the modulated feedback light beam matches the laser phase of the light source. Thus, by setting the phase modulation unit, the feedback light beam is modulated by the phase modulation unit and then injected into the light source and fed back to the laser, and the phase modulation unit is used to adjust the phase of the collimated light beam to achieve the self-injection locking phase matching condition, thereby realizing the self-injection locking narrowing line width.
[0010] In an optional implementation, the confocal optical cavity includes: a first concave reflector and a second concave reflector arranged opposite to each other, the bending direction of the first concave reflector is away from the light source, the bending direction of the second concave reflector is toward the light source, the first concave reflector and the second concave reflector have the same radius of curvature, and the distance between the first concave reflector and the second concave reflector is equal to the radius of curvature of the first concave reflector. Thus, the focus of the first concave reflector and the focus of the second concave reflector are both located at the center of the confocal optical cavity, and the focus of the first concave reflector and the focus of the second concave reflector coincide with each other. At this time, the light beam reflected by the first concave reflector and the second concave reflector will be focused at the center of the confocal optical cavity, and the collimated light beam will be emitted from the original light path after being circulated and reflected multiple times between the first concave reflector and the second concave reflector.
[0011] In an optional implementation, the reflectivity of the first concave reflector is lower than that of the second concave reflector, thereby improving the reflectivity of the light beam on the second concave reflector, reducing the transmission of the light beam on the second concave reflector, and concentrating the light beam energy on the first concave reflector.
[0012] In an optional implementation, the reflectivity of the first concave reflector is 95% to 99%, and the reflectivity of the second concave reflector is greater than 99.5%. Thus, the reflectivity of the first concave reflector is higher than the reflectivity of the second concave reflector, so that the energy of the light beam is concentrated on the first concave reflector.
[0013] In an optional implementation, the laser further includes: a coupling lens and an output component, the coupling lens is coupled to the collimating lens, the output component is coupled to the coupling lens, and the coupling lens is used to guide the collimated light output by the collimating lens to the output component. Thus, the optical path of the laser can be adjusted through the coupling lens, and the shaped laser can be transmitted to the output component.
[0014] In an optional implementation, the light source adopts a single-side light-emitting structure, and the coupling lens includes: a beam splitter element, which is arranged between the collimating lens and the confocal optical cavity, and the beam splitter element is used to split the collimated light into two paths, one of which is transmitted to the confocal optical cavity through the beam splitter element, and the other is reflected by the beam splitter element to the output component. Therefore, when the light source adopts a single-side light-emitting structure, the beam splitter element can split the collimated light beam into two beams, one of which is returned to the light source after being acted on by the confocal optical cavity to achieve self-injection locking and narrowing of the line width, thereby obtaining a beam with narrowed line width, and the other beam is emitted through the optical fiber.
[0015] In an optional implementation, the optical axis of the output component is parallel to the optical axis of the confocal optical cavity, and the coupling lens further includes: a reflector, which is coupled to the beam splitter element, and is used to reflect the collimated light reflected by the beam splitter element toward the output component. Thus, the optical path is changed by the beam splitter element and the reflector, so that the optical path of the output component is parallel to the optical path of the confocal optical cavity, reducing the occupation of the vertical space and further realizing the miniaturization of the laser.
[0016] In an optional implementation, the light source adopts a double-sided light-emitting structure, the light source includes: a first light-emitting side and a second light-emitting side, the collimating lens includes: a first collimating lens, a second collimating lens and an optical fiber, the phase modulation unit is arranged on the first light-emitting side, the coupling lens is arranged on the second light-emitting side, the first collimating lens is arranged between the first light-emitting side and the confocal optical cavity, the second collimating lens is arranged between the second light-emitting side and the coupling lens, the coupling lens is coupled with the second collimating lens, the laser emitted from the first light-emitting side is transmitted to the confocal optical cavity through the first collimating lens, and the laser emitted from the second light-emitting side is transmitted to the coupling lens through the second collimating lens. Thus, when the light source adopts a double-sided light-emitting structure, the output light beam is two beams, one beam is returned to the light source after being acted on by the confocal optical cavity to realize self-injection locking and narrowing the line width, and obtains a beam with narrowed line width, and the other beam is emitted through the optical fiber.
[0017] In an optional implementation, the optical axis of the output component is parallel to the optical axis of the confocal optical cavity, and the coupling lens includes: a first reflector and a second reflector, the first reflector is coupled to the second collimating lens, the second reflector is coupled to the first reflector, the first reflector reflects the collimated light beam to the second reflector, and the second reflector reflects the collimated light beam to the output component. Thus, the optical path is changed by the first reflector and the second reflector, so that the optical path of the output component is parallel to the optical path of the confocal optical cavity, reducing the occupation of the vertical space, and further realizing the miniaturization of the laser.
[0018] In an optional implementation, the output component includes: an isolator and an optical fiber, wherein the isolator is disposed between the coupling lens and the optical fiber so that the laser can be emitted through the optical fiber. Thus, the isolator can prevent the light source from being disturbed by reflected light and affecting the laser performance output.
[0019] In an optional implementation, the laser further includes: a sensor, the sensor is electrically connected to the phase modulation unit, the sensor is used to detect the intensity of the transmitted light of the confocal optical cavity, and the phase modulation unit is used to adjust the phase of the feedback light beam according to the intensity of the transmitted light of the confocal optical cavity. Thus, the frequency locking position of the feedback light of the confocal optical cavity can be determined, which is used as a basis for adjusting the feedback phase.
[0020] In an optional implementation, the phase modulation unit includes: any one of a temperature-controlled optical element or an electro-optical effect optical element, wherein the temperature-controlled optical element adjusts the phase of the feedback light beam by temperature, and the electro-optical effect optical element adjusts the phase of the feedback light beam by electro-optical effect. Thus, the temperature or electro-optical effect of the phase modulation unit can be adjusted according to the light intensity transmitted by the confocal optical cavity detected by the sensor to modulate the phase of the reflected light fed back by the confocal optical cavity to achieve the self-injection locking phase matching condition.
[0021] In an optional implementation, the light source is a distributed feedback laser or a distributed Bragg reflection laser.
[0022] In an optional implementation, the light source is a single-mode single-frequency laser.
[0023] In an optional implementation, the laser further comprises: a substrate, a packaging tube shell, and the laser as described above, wherein the laser is disposed on the substrate, and the laser and the substrate are disposed in the packaging tube shell. Thus, the laser can be packaged into a packaging tube shell commonly used in the optical communication industry, while reducing the packaging cost and coupling difficulty of the device, and improving the manufacturability and mass production of the device.
[0024] The second aspect of the present application provides a communication device, comprising: the laser as described above, the communication device comprising: an optical fiber sensor, a laser radar. Thus, the laser can be used in communication devices, reducing the packaging cost and coupling difficulty of the device, and improving the manufacturability and mass production of the device.
[0025] The laser provided in the embodiment of the present application at least includes: a light source, a collimating lens and a confocal optical cavity, wherein the collimating lens is located between the light source and the confocal optical cavity; the light source is used to generate laser light, and the collimating lens is used to convert the laser light of the light source into collimated light; the optical axis of the collimating lens is parallel to the optical axis of the confocal optical cavity; the light source can output a collimated light beam to the confocal optical cavity through the collimating lens, and the confocal optical cavity is used to feed back the collimated light beam to the light source after multiple reflections inside to form a feedback optical path, thereby achieving line width compression. The present application uses the confocal optical cavity as a feedback external cavity to achieve laser line width compression, and uses a collimated light beam instead of a convergent light beam to shorten the optical path. In addition, under the action of the collimating lens, the collimated light beam is incident on the confocal optical cavity along the optical axis, which is easier to align than the laser incident at an angle deviating from the optical axis of the confocal optical cavity, thereby reducing the difficulty of packaging.
[0026] In some embodiments, the laser further includes: a phase modulation unit, a sensor and a controller, wherein the phase modulation unit is located between the collimating lens and the confocal optical cavity, the sensor is arranged in the optical path of the confocal optical cavity, and the controller can adjust the temperature or electro-optical effect of the phase modulation unit according to the light intensity transmitted by the confocal optical cavity detected by the sensor, so as to modulate the phase of the reflected light fed back by the confocal optical cavity, so as to achieve the injection locked phase matching condition.
[0027] In some embodiments, the laser further includes: a coupling lens and an output component, wherein the coupling lens is used to split the light beam emitted by the light source into two paths, one of which is transmitted to the confocal optical cavity for modulation, so that the returned light beam acts on the light source to form a narrow linewidth frequency-locked laser, and the other laser is emitted through the output component. In some embodiments, the light source emits light from one side, and in other embodiments, the light source emits light from both sides, and the corresponding coupling lens structures are different. The coupling lens is also used to adjust the optical path of the output component so that the optical path of the output component is parallel to the optical path of the confocal optical cavity, thereby reducing the occupation of the vertical space and further realizing the miniaturization of the laser. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 It is a schematic diagram of the structure of a narrow line width laser;
[0029] Figure 2 It is a schematic diagram of the structure of another narrow linewidth laser;
[0030] Figure 3 A schematic diagram of the structure of a laser provided in an embodiment of the present application;
[0031] Figure 4 A schematic diagram of the structure of a confocal optical cavity provided in an embodiment of the present application;
[0032] Figure 5 A schematic diagram of the structure of another laser provided in an embodiment of the present application;
[0033] Figure 6 A schematic diagram of the structure of another laser provided in an embodiment of the present application;
[0034] Figure 7 A schematic diagram of a laser application scenario provided in an embodiment of the present application;
[0035] Figure 8 A schematic diagram of another laser application scenario provided in an embodiment of the present application;
[0036] Fig. 9 A schematic diagram of a laser working state provided in Example 1;
[0037] Fig.10 A schematic diagram of another laser working state provided in Example 2;
[0038] Fig.11 A schematic diagram of a laser packaging structure provided in an embodiment of the present application. DETAILED DESCRIPTION
[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.
[0040] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.
[0041] In addition, in the present application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to the changes in the orientation of the components in the drawings.
[0042] Laser line width: The full width at half maximum of the spectrum emitted by the light source, that is, the width between the two frequencies corresponding to half the height of the peak value (sometimes also 1 / e). When light is emitted from the laser, one or more longitudinal modes will be generated after the laser is oscillated. The frequency range of each longitudinal mode is the line width of the laser. The laser line width is determined by the quality factor of the resonant cavity. The higher the quality factor of the cavity, the narrower the laser line width.
[0043] Confocal Fabry-Perot Resonant Cavity: The confocal Fabry-Perot cavity is based on the design principle of the Fabry-Perot interferometer. The Fabry-Perot interferometer consists of two parallel mirrors, between which light is reflected multiple times to form an optical cavity, resulting in the resonant enhancement of certain wavelengths of light. The confocal Fabry-Perot cavity uses a confocal geometry, in which the mirrors in the cavity are focused. This geometry allows the light in the cavity to be reflected multiple times in a small volume, improving the optical gain and resolution of the cavity.
[0044] Distributed Feedback DFB Laser: The key feature of a DFB laser is its distributed feedback structure. In this structure, the refractive index of the laser waveguide region changes in a periodic manner. This periodic structure allows the DFB laser to emit a laser beam at a specific wavelength and achieve a single longitudinal mode (single mode) output through a reflective feedback mechanism. DFB lasers are widely used in fiber optic communications, fiber optic sensing, laser spectroscopy, photonics research, and other optical fields. They are often used as light sources in fiber optic communications, laser light sources in spectral analysis instruments, and lasers in some sensing applications.
[0045] The embodiment of the present application provides a narrow linewidth laser, which can be used as a core light source device in the fields of optical fiber sensing, laser radar, etc.
[0046] Figure 1 Figure 1 is a schematic diagram of the structure of a narrow linewidth laser. Figure 1As shown, the narrow linewidth laser includes: a light source 101, an attenuator 102 and a confocal optical cavity 103. The laser emitted by the light source 101 enters the confocal optical cavity 103 through the attenuator 102. The confocal optical cavity 103 can reflect the incident laser toward the light source 101 to change the output linewidth of the light source 101.
[0047] However, the medium of the confocal optical cavity 103 is air, which is relatively large and not conducive to miniaturization.
[0048] Figure 2 Figure 1 is a schematic diagram of the structure of another narrow linewidth laser. Figure 2 As shown, the narrow linewidth laser includes: a light source 101 , a converging lens 104 and a confocal optical cavity 103 .
[0049] In some embodiments, the confocal optical cavity 103 is a solid CFP optical cavity based on a 1 cm cavity length.
[0050] like Figure 2 As shown, the laser is incident at an angle deviating from the optical axis of the CFP optical cavity, which can avoid the direct reflection of the injected laser from the cavity surface to interfere with the laser locking. The laser incident into the optical cavity is reflected multiple times in the cavity and then transmitted, and the transmitted light is fed back to the light source 101 to achieve frequency selection and filtering to narrow the laser line width.
[0051] The confocal optical cavity 103 is a multi-mode optical cavity. Theoretically, without considering high-order factors such as aberration and spherical aberration, when the cavity length is equal to the radius of curvature of the sphere, the mode frequency is degenerate, and the injected light spot does not need to match the fundamental mode field. Figure 2 As shown, the laser is focused by the lens and enters the confocal optical cavity 103, so that the incident laser can better match the low-order mode and reduce the adverse effects of the splitting of the high-order mode.
[0052] However, since the laser emission divergence angle is much smaller than the optical cavity mode divergence angle, and the lens image distance is much larger than the object distance, the optical path will be lengthened, making it difficult to further miniaturize and achieve miniaturization.
[0053] To this end, an embodiment of the present application provides a small narrow-linewidth laser.
[0054] Figure 3 This is a schematic diagram of the structure of a laser provided in an embodiment of the present application. Figure 3 As shown, the laser includes: a light source 101 , a collimating lens 105 and a confocal optical cavity 103 , and the collimating lens 105 is located between the light source 101 and the confocal optical cavity 103 .
[0055] In some embodiments, the light source may be a light source chip. For example, the light source 101 may be a DFB laser or a distributed Bragg reflector (DBR) laser. For example, the light source 101 may be a DFB semiconductor laser for generating laser light.
[0056] In some embodiments, the light source may be a single-mode single-frequency laser. Taking a DFB semiconductor laser as an example, the refractive index of the waveguide region of the DFB semiconductor laser changes in a periodic manner. This periodic structure allows the DFB semiconductor laser to emit a laser beam at a specific wavelength and achieve a single longitudinal mode (single mode) output through a reflection feedback mechanism, that is, the light source 101 is a single-mode single-frequency laser.
[0057] The collimating lens 105 is used to convert the laser light generated by the light source 101 into a collimated light beam. A collimated light beam refers to a light beam with a very small beam divergence angle, so the beam radius does not change significantly after a certain propagation distance.
[0058] The divergent light beam can be converted into a collimated light beam by a lens or a curved mirror, and the present embodiment does not limit the structure of the collimating lens 105. In some embodiments, the collimating lens 105 can be a single lens, such as a plano-convex or bi-convex lens.
[0059] In some embodiments, the collimating lens 105 may be a doublet lens.
[0060] In some embodiments, the optical axis of the collimating lens 105 is parallel to the optical axis of the confocal optical cavity 103. In this way, the collimated light beam can be incident at an angle perpendicular to the confocal optical cavity 103, which is easier to align. Compared with the method of setting a converging lens 104 in the related art to reduce the light spot, the optical path is shortened, which is conducive to the miniaturization of the product.
[0061] In the above embodiment, the optical axis of the collimating lens 105 and the optical axis of the confocal optical cavity 103 may be parallel and there may be an error, and the error range is, for example, within 5°.
[0062] In some embodiments, the optical axis of the collimating lens 105 is parallel to the optical axis of the confocal optical cavity 103, and the collimating lens 105 is arranged opposite to the confocal optical cavity 103, so that the collimated light can enter the confocal optical cavity 103 along the optical axis of the optical cavity.
[0063] Therefore, compared with the case where the laser is incident at an angle deviating from the optical axis of the confocal optical cavity 103 in order to avoid direct reflection of the injected laser from the cavity surface interfering with laser locking, in this embodiment, the laser is incident on the confocal optical cavity 103 along the optical axis, which is easier to align and reduces the difficulty of packaging.
[0064] The confocal optical cavity 103 is used to receive collimated light and feed the collimated light beam back to the light source 101 after multiple reflections inside the cavity, so that part of the reflected light forms a feedback light beam, thereby achieving laser line width compression.
[0065] In some embodiments, Figure 4 As shown, the confocal optical cavity 103 includes a first concave reflecting mirror 1031 and a second concave reflecting mirror 1032 relative to each other. The bending direction of the first concave reflecting mirror 1031 is away from the light source 101, and the bending direction of the second concave reflecting mirror 1032 is toward the light source 101. The first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 have the same curvature radius, and the distance between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 is equal to the curvature radius of the first concave reflecting mirror 1031.
[0066] For the structure of the above-mentioned confocal optical cavity 103, the focal length of the concave reflecting mirror is equal to half of its curvature radius R. In this embodiment, the distance between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 is equal to the curvature radius of the first concave reflecting mirror 1031, that is, the first concave reflecting mirror 1031 is arranged at the position of the curvature radius R of the second concave reflecting mirror 1032, that is, the center distance L between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 and the curvature radius R of the second concave reflecting mirror 1032 satisfy: L=R. In this way, the focus of the first concave reflecting mirror 1031 and the focus of the second concave reflecting mirror 1032 are both located on the central plane of the confocal optical cavity 103, and the focus of the first concave reflecting mirror 1031 and the focus of the second concave reflecting mirror 1032 coincide with each other. At this time, the light beam reflected by the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 will be focused at the center of the confocal optical cavity 103, and the collimated light beam will be emitted from the original light path after being circulated and reflected multiple times between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032.
[0067] Further, Figure 4 yes Figure 3 Schematic diagram of the incident feedback optical path of the confocal cavity shown in Figure 1. Figure 3 and Figure 4In this embodiment, the collimated light beam is vertically incident on the first concave reflecting mirror 1031, and the focal points on the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 are located on the optical path of the collimated light beam. In this way, the light source 101 can be emitted toward the common focal plane of the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032. For example, the collimated light beam is incident on the first concave reflecting mirror 1031, and is incident on the reflecting surface of the second concave reflecting mirror 1032 through the focal point under the action of the first concave reflecting mirror 1031. Then, Under the action of the second concave reflector 1032, the light beam is reflected for the first time, and the first concave reflector 1031 will reflect the light beam for the second time along the original path. Then, the second concave reflector 1032 makes the light beam reflect for the third time toward the focus of the first concave reflector 1031. The reflected light beam is reflected for the fourth time at the focus position of the first concave reflector 1031. After the fourth reflection, the reflected light beam will return to the focus position of the first concave reflector 1031 again in a similar reflection manner as described above. Therefore, after the collimated light beam is incident on the focus, it will be cyclically reflected between the first concave reflector 1031 and the second concave reflector 1032, thereby forming resonance. In this embodiment, the first concave reflector 1031 can be set to have the ability of partial transmission and partial reflection, that is, part of the reflected light beam in the cavity is transmitted by the first concave reflector 1031 and fed back to the light source 101 along the original path of the collimated light beam.
[0068] In this embodiment, the confocal optical cavity 103 serves as the external cavity of the light source 101, and can feed back the collimated light beam along the original path to the light source 101 after internal reflection, thereby forming external cavity frequency self-injection locking and achieving line width narrowing.
[0069] In the above embodiment, the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 form a single solid structure. In some embodiments, the confocal cavity can also be a semi-confocal cavity.
[0070] The narrow linewidth external cavity laser device based on the confocal optical cavity 103 provided in the embodiment of the present application includes a light source 101, a collimating lens 105 and a confocal optical cavity 103. The light source 101 can output a collimated light beam to the confocal optical cavity 103 through the collimating lens 105. The confocal optical cavity 103 is used to feed back the collimated light beam to the light source 101 after internal reflection to form a feedback light path. The confocal optical cavity 103 satisfies the external cavity self-injection locking condition to form a frequency-locked laser. Among them, by setting the confocal optical cavity 103 to include a first concave reflector 1031 and a second concave reflector 1032, and the focus of the second concave reflector 1032 on the first concave reflector 1031 is located on the light path of the collimated light beam, the collimated light beam is cyclically reflected multiple times between the first concave reflector 1031 and the second concave reflector 1032 and then emitted from the original light path, thereby achieving linewidth compression. The embodiment of the present application solves the problem of large volume of existing narrow linewidth laser devices. The first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 are used to form a confocal optical cavity 103. The confocal optical cavity 103 is used as a feedback external cavity to achieve narrow linewidth frequency-locked laser. At the same time, the feedback external cavity structure composed of two concave reflecting mirrors is smaller in volume, which is more convenient for the layout of the feedback external cavity, and is conducive to the miniaturization of the narrow linewidth laser device.
[0071] In some embodiments, the first concave reflector 1031 and the second concave reflector 1032 have the ability of multiple internal reflections, and they can also achieve the function of transmitting light. For the first concave reflector 1031 and the second concave reflector 1032, when the collimated light beam is incident on the focal position of the first concave reflector 1031, there will be at least partial energy transmission, and the transmitted light enters the first concave reflector 1031 and the second concave reflector 1032, and forms a circular reflection between the first concave reflector 1031 and the second concave reflector 1032. At the same time, in this process, partial energy transmission will also be generated at the reflection position of the first concave reflector 1031 and the second concave reflector 1032. At this time, a transmitted light beam can be selected as the frequency-locked laser output according to the laser light emitting direction, and of course, an additional beam splitter can be set on the optical path of the collimated light beam to be responsible for the output of the frequency-locked laser.
[0072] In some embodiments, the present application can arrange a spectroscopic element to be located in the optical path of a collimated light beam, for splitting the collimated light beam as a frequency-locked laser output, and can specifically arrange to use the reflected light of the beam splitter as the frequency-locked laser output, or can specifically arrange to use the transmitted light of the spectroscopic element as the frequency-locked laser output.
[0073] In some embodiments, considering the feedback energy of the collimated light beam in the confocal optical cavity 103 , in the embodiments of the present application, the reflectivity and transmittance of the first concave reflecting mirror 1031 and the second concave reflecting mirror 1032 may be designed separately.
[0074] For example, in the optical path of the collimated light beam, the second concave reflector 1032 is located on the side of the first concave reflector 1031 away from the light source 101, and the reflectivity of the second concave reflector 1032 is greater than the reflectivity of the first concave reflector 1031. In this way, the reflective surface of the second concave reflector 1032 is opposite to the light source 101, so that the laser in the confocal optical cavity 103 can be more easily reflected back to the light source 101 by the original path under the action of the second concave reflector 1032.
[0075] At this time, when the collimated light beam is incident on the confocal optical cavity 103, the reflectivity of the light beam in the cavity on the second concave reflecting mirror 1032 is greater than the reflectivity of the first concave reflecting mirror 1031, so that the reflection ability of the light beam on the second concave reflecting mirror 1032 can be improved, and the transmission of the light beam on the second concave reflecting mirror 1032 can be reduced, so that the energy of the light beam is concentrated on the first concave reflecting mirror 1031. More specifically, the reflectivity of the second concave reflecting mirror 1032 can be set to be much greater than the reflectivity of the first concave reflecting mirror 1031, or the second concave reflecting mirror 1032 can be set to have no transmission ability. At this time, there is only light reflection at the second concave reflecting mirror 1032, and there is no light transmission, which increases the energy of the laser fed back along the original path of the collimated light beam.
[0076] For example, the reflectivity of the first concave reflecting mirror 1031 is 95% to 99%, and the reflectivity of the second concave reflecting mirror 1032 is greater than 99.5%.
[0077] In the above embodiment, the reflectivity design of the second concave reflector 1032 and the first concave reflector 1031 needs to be determined according to the positions of the second concave reflector 1032 and the first concave reflector 1031 on the optical path of the collimated light beam. It can be understood that the embodiment of the present application aims to increase the laser energy fed back. Therefore, when the first concave reflector 1031 is located on the side of the second concave reflector 1032 away from the light source 101 and the collimating lens 105 on the optical path of the collimated light beam, the reflectivity of the first concave reflector 1031 can be selected to be greater than the reflectivity of the second concave reflector 1032. At this time, the second concave reflector 1032 is the transmission surface of the feedback laser, which relatively increases the reflection ability of the first concave reflector 1031 and reduces the light transmission ability of the first concave reflector 1031, so that more energy in the cavity can be transmitted by the second concave reflector 1032, thereby increasing the laser energy fed back.
[0078] In some embodiments, Figure 5As shown, the laser further includes a phase modulation unit 106. The phase modulation unit 106 is arranged between the collimating lens 105 and the confocal optical cavity 103. The phase modulation unit 106 is located on the optical path of the collimated light beam. The collimated light passing through the collimating lens 105 enters the phase modulation unit 106. The phase modulation unit 106 can emit the received collimated light outward to the confocal optical cavity 103. Part of the reflected light is reflected multiple times in the confocal optical cavity 103 and then passes through the confocal optical cavity 103. The reflected light passing through the confocal optical cavity 103 forms a feedback light beam. The feedback light beam is injected into the light source 101 through the phase modulation unit 106. The phase modulation unit 106 is used to perform phase modulation on the feedback light beam so that the phase of the modulated feedback light beam matches the phase of the laser generated by the light source. Thus, the reflected light passing through the confocal optical cavity 103 is modulated by the phase modulation unit 106 and then injected into the light source 101 and fed back to the laser. The phase modulation unit 106 is used to adjust the phase of the feedback light beam so that the confocal optical cavity 103 meets the external cavity self-injection locking condition, forms a frequency-locked laser, and realizes self-injection locking to narrow the linewidth.
[0079] In some embodiments, the phase modulation unit 106 may include a temperature-controlled optical element or an electro-optical effect optical element disposed on the optical path of the feedback light beam, wherein the temperature-controlled optical element is used to change its own refractive index according to temperature changes to adjust the phase of the feedback light beam, and the electro-optical effect optical element is used to change its own refractive index according to the electro-optical effect to adjust the phase of the feedback light beam. The change in refractive index can change the optical path of the light beam, that is, to achieve phase adjustment of the light beam, so that the entire laser device meets the external cavity self-injection locking condition to form a frequency-locked laser. The phase modulation unit 106 is disposed in the optical path, and can perform phase modulation on the feedback light beam, so that the modulated feedback light beam matches the phase of the light source 101.
[0080] In some embodiments, the phase may be changed by temperature or electro-optical effects.
[0081] In some embodiments, Figure 6 As shown, the laser also includes a sensor 107, which is used to detect the intensity of the laser emitted by the confocal optical cavity 103. The frequency locking position of the feedback light peak of the confocal optical cavity 103 can be determined, which serves as a basis for adjusting the feedback phase.
[0082] like Figure 6 As shown, the sensor 107 is electrically connected to the phase modulation unit 106. The phase modulation unit 106 can adjust the temperature or electro-optical effect of the phase modulation unit 106 according to the light intensity transmitted by the confocal optical cavity 103 detected by the sensor 107 to modulate the phase of the feedback light beam fed back by the confocal optical cavity so that the modulated feedback light beam matches the phase of the light source 101.
[0083] Therefore, the laser provided in the embodiment of the present application, by providing the phase modulation unit 106 and the confocal optical cavity 103, enables the modulated feedback light beam to be self-injected into the light source 101, thereby achieving line width narrowing.
[0084] In the above embodiments, the laser can achieve external cavity self-injection locking to form frequency-locked laser. Figure 7 , Figure 8 As shown, the laser also includes: an output component 109 and a coupling lens 110, wherein the coupling lens 110 is coupled to the collimating lens 105, and the output component 109 is coupled to the coupling lens 110, wherein the coupling lens 110 is used to guide the collimated light output by the collimating lens 105 to the output component 109, and the output component 109 is used to emit the frequency-locked laser output by the light source 101 outward.
[0085] In some embodiments, the output component 109 includes: an isolator 1091 and an optical fiber 1092, wherein the isolator 1091 is disposed between the coupling lens 110 and the optical fiber 1092. The isolator 1091 can prevent the light source from being affected by the reverse light from the reflection and causing the spectrum purity to decrease, thereby improving the spectrum purity of the light source.
[0086] For different optical paths, the composition of the coupling lens 110 is different. For example, in some embodiments, Figure 7 As shown, the light source 101 is a single-sided light source 101, and the coupling lens 110 includes: a spectroscopic element 1101, which is arranged between the collimating lens 105 and the phase modulation unit 106, and the spectroscopic element 1101 is used to split the collimated light into two paths, one of which is transmitted to the confocal optical cavity 103 through the spectroscopic element 1101, and the other is reflected by the spectroscopic element 1101 to the optical fiber 1092.
[0087] The embodiment of the present application does not limit the structure of the beam splitter element 1101. In some embodiments, the beam splitter element 1101 may be a polarization beam splitter prism. The polarization beam splitter prism is used to split the incident laser into two beams with different polarization directions, for example, the beam transmitted to the confocal optical cavity 103 is a horizontally polarized beam, and the beam transmitted to the optical fiber 1092 is a vertically polarized beam.
[0088] In order to further miniaturize the laser, in some embodiments, the optical axis of the output component 109 can be parallel to the optical axis of the confocal optical cavity 103. To this end, the coupling lens 110 can also include: a reflector 1102, the reflector 1102 is coupled to the beam splitter 1101, and the reflector 1102 is used to reflect the collimated light reflected by the beam splitter 1101 toward the optical fiber 1092.
[0089] Therefore, the optical path can be changed by the beam splitter and the reflector 1102 so that the optical path of the optical fiber 1092 is parallel to the optical path of the confocal optical cavity 103, thereby reducing the occupation of the vertical space and realizing the miniaturization of the laser.
[0090] In other embodiments, Figure 8 As shown, the light source 101 is a bidirectional light source 101. The light source 101 includes: a first light emitting side and a second light emitting side. The phase modulation unit 106 is arranged on the first light emitting side, and the coupling lens 110 is arranged on the second light emitting side. The collimating lens 105 includes: a first collimating lens 105 and a second collimating lens 105, the first collimating lens 105 is arranged between the first light emitting side and the phase modulation unit 106, and the second collimating lens 105 is arranged between the second light emitting side and the coupling lens 110. The bidirectional light source 101 is used to generate two laser beams, one laser beam is emitted from the first light emitting side, transmitted to the phase modulation unit 106 through the first collimating lens 105, and the other laser beam is emitted from the second light emitting side, transmitted to the coupling lens 110 through the second collimating lens 105.
[0091] The description of the output component 109 can refer to the above embodiment and will not be repeated here. In some embodiments, the optical axis of the optical fiber 1092 is parallel to the optical axis of the confocal optical cavity 103, and the coupling lens 110 includes: a first reflector 1103 and a second reflector 1104, the first reflector 1103 is coupled with the second collimating lens 105, the second reflector 1104 is coupled with the first collimating lens, the first reflector 1103 reflects the collimated light beam to the second reflector 1104, and the second reflector reflects the collimated light beam to the optical fiber 1092.
[0092] The structures of lasers with different optical paths provided by the present application are described below in combination with Embodiment 1 and Embodiment 2.
[0093] Embodiment 1:
[0094] Fig. 9 This is a schematic diagram of the structure of a laser provided in Example 1. Fig. 9 As shown, the laser comprises: a light source 101, a collimating lens 105, a phase modulation unit 106, a confocal optical cavity 103, a coupling lens 110, an output component 109 and a sensor 107. The light source 101 adopts a single-side light emitting structure.
[0095] See also Fig. 9 , the light source 101, the collimating lens 105, the beam splitter 1101, the phase modulation unit 106, the confocal optical cavity 103 and the sensor 107 are arranged in sequence along the x direction, and the optical axes coincide.
[0096] In some embodiments, the coupling lens 110 includes: a beam splitter 1101 and a reflector 1102. The beam splitter 1101 is used to split the incident laser into two beams with different polarization directions, for example, the incident collimated beam can be split into a horizontally polarized beam and a vertically polarized beam.
[0097] The reflector 1102 can be used to change the optical path of the vertically polarized light beam, so that the vertically polarized light beam becomes parallel to the horizontally polarized light beam under the action of the reflector 1102, thus obtaining two parallel horizontally polarized light beams, reducing the occupation of vertical space.
[0098] In some embodiments, the horizontally polarized light beam emitted by the beam splitter 1101 may be transmitted to the confocal optical cavity 103 , and the vertically polarized light beam emitted by the polarization element may be transmitted to the output component 109 .
[0099] In other embodiments, the vertically polarized light beam emitted by the beam splitter element 1101 may be transmitted to the confocal optical cavity 103 , and the horizontally polarized light beam emitted by the polarization element may be transmitted to the output component 109 .
[0100] In some embodiments, the output component 109 includes an isolator 1091 and an optical fiber 1092. This embodiment is described by taking the example of transmitting the horizontally polarized light beam emitted by the beam splitter 1101 to the confocal cavity 103 and transmitting the vertically polarized light beam emitted by the polarization element to the output component 109.
[0101] In some embodiments, the sensor 107 is used to detect the intensity of the laser emitted from the confocal cavity 103. The frequency-locking position of the feedback light peak of the confocal cavity 103 can be determined, and the phase modulation unit 106 uses this as a basis for adjusting the feedback phase.
[0102] Next reference Fig. 9 The reflector 1102, the isolator 1091 and the optical fiber 1092 are arranged in sequence along the x direction, and the optical axes of the reflector 1102, the isolator 1091 and the optical fiber 1092 are parallel to the optical axes of the light source 101, the collimating lens 105, the spectrometer 1101, the phase modulation unit 106 and the confocal optical cavity 103.
[0103] There may be an error in the coincidence of the optical axes of the light source 101, the collimating lens 105, the beam splitter 1101, the phase modulation unit 106 and the confocal optical cavity 103. The error range may be 5°.
[0104] The laser emitted by the light source 101 enters the collimating lens 105, and the collimating lens 105 can convert the laser of the light source 101 into a collimated light beam. The collimated light beam is divided into two paths after passing through the spectroscopic element 1101. One path passes through the spectroscopic element 1101 and is transmitted to the confocal optical cavity 103 through the phase modulation unit 106, and the other path is reflected by the spectroscopic element 1101 to the reflector 1102, and is reflected by the reflector 1102 in turn and coupled into the optical fiber 1092 through the isolator 1091.
[0105] In some embodiments, the confocal optical cavity 103 includes a first concave reflecting mirror 1031 and a second concave reflecting mirror 1102 relative to each other, the bending direction of the first concave reflecting mirror 1031 is away from the light source 101, the bending direction of the second concave reflecting mirror 1102 is toward the light source 101, the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102 have the same curvature radius, and the distance between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102 is equal to the curvature radius of the first concave reflecting mirror 1031.
[0106] The transmitted light beam entering the confocal optical cavity 103 is reflected multiple times by the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102, and the reflected light beam is focused at the center of the confocal optical cavity 103. The collimated light beam on the second concave reflecting mirror 1102 is reflected multiple times between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102, and then emitted from the original light path and injected into the light source 101, thereby achieving line width compression.
[0107] This embodiment solves the problem of large volume of existing narrow linewidth laser devices. The first concave reflecting mirror 1031 and the second concave reflecting mirror 1102 are used to form a confocal optical cavity 103, and the confocal optical cavity 103 is used as a feedback external cavity to realize narrow linewidth frequency-locked laser. At the same time, a collimated beam is used instead of a convergent beam, thereby shortening the optical path.
[0108] In addition, the collimated light beam is incident at an angle perpendicular to the confocal optical cavity 103. Compared with the laser being incident at an angle deviating from the optical axis of the confocal optical cavity 103, in this embodiment, the laser is incident on the confocal optical cavity 103 along the optical axis, which is easier to align and reduces the difficulty of packaging.
[0109] In addition, the optical path is changed by the beam splitter and the reflector 1102 so that the optical path of the optical fiber 1092 is parallel to the optical path of the confocal optical cavity 103, thereby reducing the occupation of the vertical space and realizing the miniaturization of the laser.
[0110] Embodiment 2:
[0111] Fig.10 This is a schematic diagram of the structure of a laser provided in Example 2. Fig.10As shown, the laser includes: a light source 101, a collimating lens 105, a phase modulation unit 106, a confocal optical cavity 103, a coupling lens 110, an output component 109 and a sensor 107.
[0112] The light source 101 is a bidirectional light source 101. The light source 101 includes: a first light emitting side and a second light emitting side. The phase modulation unit 106 is arranged on the first light emitting side, and the coupling lens 110 is arranged on the second light emitting side. The collimating lens 105 includes: a first collimating lens 105 and a second collimating lens 105, the first collimating lens 105 is arranged between the first light emitting side and the phase modulation unit 106, and the second collimating lens 105 is arranged between the second light emitting side and the coupling lens 110. The bidirectional light source 101 is used to generate two laser beams, one laser beam is emitted from the first light emitting side, transmitted to the phase modulation unit 106 through the first collimating lens 105, and the other laser beam is emitted from the second light emitting side, and transmitted to the output component 109 through the second collimating lens 105.
[0113] In some embodiments, the sensor 107 is used to detect the intensity of the laser emitted from the confocal cavity 103. The frequency-locking position of the feedback light peak of the confocal cavity 103 can be determined, and the phase modulation unit 106 uses this as a basis for adjusting the feedback phase.
[0114] See also Fig.10 , the light source 101, the collimating lens 105, the phase modulation unit 106 and the confocal optical cavity 103 are arranged in sequence along the x direction, and the optical axes coincide.
[0115] In some embodiments, the coupling lens 110 includes: a first reflector 1103 and a second reflector 1104, the first reflector 1103 is coupled to the second collimating lens 105, the second reflector 1104 is coupled to the first collimating lens, the first reflector 1103 reflects the collimated light beam toward the second reflector 1104, and the second reflector reflects the collimated light beam toward the optical fiber 1092.
[0116] The first reflector 1103 can be used to change the optical path of the light beam emitted from the second light emitting side, so that the light beam emitted from the second light emitting side changes from an optical path in the x direction to an optical path in the y direction under the action of the first reflector 1103. The second reflector 1104 can be used to change the optical path of the light beam reflected by the first reflector 1103, so that the light beam reflected by the first reflector 1103 changes from an optical path in the y direction to an optical path in the x direction under the action of the second reflector 1104. In this way, two parallel horizontally polarized light beams are obtained, reducing the occupation of the vertical space.
[0117] Therefore, in this embodiment, the optical path is changed by the first reflector 1103 and the second reflector 1104 so that the optical path of the optical fiber 1092 is parallel to the optical path of the confocal optical cavity 103, thereby reducing the occupation of the vertical space and realizing the miniaturization of the laser.
[0118] Next reference Fig.10 The second reflector 1104, the isolator 1091 and the optical fiber 1092 are arranged in sequence along the x direction, and the optical axes of the second reflector 1104, the isolator 1091 and the optical fiber 1092 are parallel to the optical axes of the light source 101, the collimating lens 105, the phase modulation unit 106 and the confocal optical cavity 103.
[0119] There may be an error in the coincidence of the optical axes of the light source 101, the collimating lens 105, the phase modulation unit 106 and the confocal optical cavity 103. The error range may be 5°.
[0120] During operation, the laser emitted from the first light output side of the light source 101 enters the first collimating lens 105 , and the first collimating lens 105 can convert the laser of the light source 101 into a collimated light beam, which is transmitted to the confocal optical cavity 103 via the phase modulation unit 106 .
[0121] The laser light emitted from the second light output side of the light source 101 is reflected by the first reflector 1103 to the second reflector 1104 , and then coupled into the optical fiber 1092 through the isolator 1091 .
[0122] In some embodiments, the confocal optical cavity 103 includes a first concave reflecting mirror 1031 and a second concave reflecting mirror 1102 relative to each other, the bending direction of the first concave reflecting mirror 1031 is away from the light source 101, the bending direction of the second concave reflecting mirror 1102 is toward the light source 101, the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102 have the same curvature radius, and the distance between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102 is equal to the curvature radius of the first concave reflecting mirror 1031.
[0123] The transmitted light beam entering the confocal optical cavity 103 is reflected multiple times by the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102, and the reflected light beam is focused at the center of the confocal optical cavity 103. The collimated light beam on the second concave reflecting mirror 1102 is reflected multiple times between the first concave reflecting mirror 1031 and the second concave reflecting mirror 1102, and then emitted from the original light path and injected into the light source 101, thereby achieving line width compression.
[0124] Therefore, in this embodiment, the first concave reflector 1031 and the second concave reflector 1102 are used to form a confocal optical cavity 103 to achieve narrow linewidth frequency-locked laser. In addition, by setting the first collimating lens 105 and the second collimating lens 105, a collimated beam is used instead of a convergent beam, and the optical path is shortened. In addition, under the action of the collimating lens 105, the collimated beam is incident at an angle perpendicular to the confocal optical cavity 103. Compared with the laser incident at an angle deviating from the optical axis of the confocal optical cavity 103, in this embodiment, the laser is incident along the optical axis of the confocal optical cavity 103, which is easier to align and reduces the difficulty of packaging.
[0125] The present application also provides a laser packaging structure, such as Fig.11 As shown, the laser packaging structure includes: a substrate 10 , and the laser as above, and the laser is arranged on the substrate 10 .
[0126] In some embodiments, the packaging structure of the laser further includes: a packaging tube shell, in which the substrate 10 and the laser are both arranged. The packaging tube shell may be a butterfly tube shell or a box packaging tube shell.
[0127] The laser provided in the embodiment of the present application at least includes: a light source, a collimating lens and a confocal optical cavity, wherein the collimating lens is located between the light source and the confocal optical cavity; the light source is used to generate laser light, and the collimating lens is used to convert the laser light generated by the light source into collimated light; the optical axis of the collimating lens is parallel to the optical axis of the confocal optical cavity; the light source can output a collimated light beam to the confocal optical cavity through the collimating lens, and the confocal optical cavity is used to feed back the collimated light beam to the light source after multiple reflections inside to form a feedback light beam injected into the light source, and the confocal optical cavity satisfies the external cavity self-injection locking condition to achieve line width compression. The present application uses the confocal optical cavity as the feedback external cavity to achieve narrow line width frequency-locked laser, and uses a collimated light beam instead of a convergent light beam to shorten the optical path. In addition, under the action of the collimating lens, the collimated light beam is incident on the confocal optical cavity along the optical axis, which is easier to align than the laser incident at an angle deviating from the optical axis of the confocal optical cavity, reducing the difficulty of packaging.
[0128] In some embodiments, the laser further includes: a phase modulation unit, a sensor and a controller, wherein the phase modulation unit is located between the collimating lens and the confocal optical cavity, the sensor is arranged in the optical path of the confocal optical cavity, and the controller can adjust the temperature or electro-optical effect of the phase modulation unit according to the light intensity transmitted by the confocal optical cavity detected by the sensor, so as to modulate the phase of the feedback light beam fed back by the confocal optical cavity, so that the modulated feedback light beam matches the phase of the light source.
[0129] In some embodiments, the laser further includes: a coupling lens and an output component, wherein the coupling lens is used to split the light beam emitted by the light source into two paths, one of which is transmitted to the confocal optical cavity for modulation, so that the returned light beam acts on the light source to form a narrow linewidth frequency-locked laser, and the other laser is emitted through the output component. In some embodiments, the light source emits light from one side, and in other embodiments, the light source emits light from both sides, and the corresponding coupling lens structures are different. The coupling lens is also used to adjust the optical path of the output component so that the optical path of the output component is parallel to the optical path of the confocal optical cavity, thereby reducing the occupation of the vertical space and further realizing the miniaturization of the laser.
[0130] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A laser, characterized in that: include: A light source, a collimating lens and a confocal optical cavity, wherein the collimating lens is located between the light source and the confocal optical cavity; The light source is used to generate laser light, and the collimating lens is used to convert the laser light generated by the light source into collimated light; the collimated light is parallel to the optical axis of the confocal optical cavity; The confocal optical cavity is used to receive the collimated light and, after multiple reflections on the collimated light, make part of the reflected light form a feedback light beam to be injected into the light source.
2. The laser according to claim 1, characterized in that The laser also includes: a phase modulation unit, which is arranged between the collimating lens and the confocal optical cavity, and the feedback light beam is injected into the light source through the phase modulation unit. The phase modulation unit is used to phase modulate the feedback light beam so that the phase of the modulated feedback light beam matches the laser phase produced by the light source.
3. The laser according to claim 2, characterized in that The laser also includes: a sensor, which is electrically connected to the phase modulation unit, and is used to detect the intensity of the transmitted light of the confocal optical cavity. The phase modulation unit is used to adjust the phase of the feedback light beam according to the intensity of the transmitted light of the confocal optical cavity.
4. The laser according to claim 2 or 3, characterized in that: The phase modulation unit includes: any one of a temperature-controlled optical element or an electro-optical effect optical element, wherein the temperature-controlled optical element adjusts the phase of the feedback light beam by temperature, and the electro-optical effect optical element adjusts the phase of the feedback light beam by electro-optical effect.
5. The laser according to any one of claims 1 to 4, characterized in that: The confocal optical cavity includes: a first concave reflecting mirror and a second concave reflecting mirror arranged opposite to each other, wherein the bending direction of the first concave reflecting mirror is away from the light source, and the bending direction of the second concave reflecting mirror is toward the light source, the first concave reflecting mirror and the second concave reflecting mirror have the same curvature radius, and the distance between the first concave reflecting mirror and the second concave reflecting mirror is equal to the curvature radius of the first concave reflecting mirror.
6. The laser according to claim 5, characterized in that The reflectivity of the first concave reflecting mirror is lower than the reflectivity of the second concave reflecting mirror.
7. The laser according to claim 6, characterized in that The reflectivity of the first concave reflecting mirror is 95% to 99%, and the reflectivity of the second concave reflecting mirror is greater than 99.5%.
8. The laser according to any one of claims 1 to 7, characterized in that: The laser further comprises: a coupling lens and an output assembly, wherein the coupling lens is coupled to the collimating lens, the output assembly is coupled to the coupling lens, and the coupling lens is used to guide the collimated light output by the collimating lens to the output assembly.
9. The laser according to claim 8, characterized in that The coupling lens comprises: a beam splitter element, which is arranged between the collimating lens and the confocal optical cavity, and is used to split the collimated light into two paths, one of which is transmitted to the confocal optical cavity through the beam splitter element, and the other is reflected by the beam splitter element to the output component.
10. The laser according to claim 9, characterized in that The optical axis of the output component is parallel to the optical axis of the confocal optical cavity. The coupling lens further comprises: a reflector coupled to the beam splitter element, and the reflector is used to reflect the collimated light reflected by the beam splitter element toward the output component.
11. The laser according to claim 8, characterized in that The light source comprises: a first light exit side and a second light exit side, and the collimating lens comprises: a first collimating lens and a second collimating lens; The phase modulation unit is arranged at the first light exiting side, the first collimating lens is arranged between the first light exiting side and the confocal optical cavity, and the laser light emitted by the first light exiting side is transmitted to the confocal optical cavity through the first collimating lens; The coupling lens is arranged on the second light emitting side, the second collimating lens is arranged between the second light emitting side and the coupling lens, the coupling lens is coupled with the second collimating lens, and the laser emitted from the second light emitting side is transmitted to the coupling lens through the second collimating lens.
12. The laser according to claim 11, characterized in that The optical axis of the output component is parallel to the optical axis of the confocal optical cavity, and the coupling lens includes: a first reflector and a second reflector, the first reflector is coupled to the second collimating lens, the second reflector is coupled to the first reflector, the first reflector reflects the collimated light toward the second reflector, and the second reflector reflects the collimated light toward the output component.
13. The laser according to any one of claims 8 to 12, characterized in that: The output component includes: an isolator and an optical fiber, wherein the isolator is arranged between the coupling lens and the optical fiber.
14. The laser according to any one of claims 1 to 13, characterized in that: The light source is any one of a distributed feedback DFB laser and a distributed Bragg reflector DBR laser.
15. The laser according to any one of claims 1 to 14, characterized in that: The light source is a single-mode single-frequency laser.
16. The laser according to any one of claims 1 to 15, characterized in that: The laser further comprises: a substrate and a packaging shell, the laser is arranged on the substrate, and the laser and the substrate are arranged in the packaging shell.
17. A communication device, characterized in that: include: The laser according to any one of claims 1 to 16, wherein the communication device comprises: an optical fiber sensor, a laser radar.