Off-axis folded transceiver integrated optical device

Abstract

The utility model discloses a kind of off-axis foldback type transceiving integrated optical devices, it is related to optical control technical field.Optical device is located in mirror frame, optical device includes laser, transmission beam expander system, transceiver separation module, plane mirror, reflection beam expander system and located in the optical fiber coupling system of transceiver separation module side in order along excitation light line, the reflection surface of plane mirror is set to transceiver separation module and with excitation light line is preset angle, so that the excitation light line that transmits out transceiver separation module is reflected to reflection beam expander system, so that the light path between laser and plane mirror is perpendicular to the light path between plane mirror and reflection beam expander system, to realize the beam expansion of beam expansion ratio greater than or equal to 30X.The optical device of the application can realize high beam expansion ratio, large aperture output, low wavefront error and transceiving integration.

Description

Technical Field

[0001] This utility model belongs to the field of optical instrument technology, specifically relating to an off-axis folding-back integrated optical transceiver device. Background Technology

[0002] In long-range detection applications, high-precision lidar systems require the emitted beam to have an extremely low collimation divergence angle, while the receiving system must have a powerful light collection capability. This drives the development of telescope systems towards larger apertures and higher beam magnification.

[0003] However, existing technologies face challenges in achieving such high-performance optical systems, including the tolerance sensitivity of high-magnification systems and the thermal stability and assembly difficulty of large-aperture reflective systems. Specifically, achieving high magnification using a single transmissive beam expander (e.g., exceeding 30X magnification) requires extremely stringent tolerance control over the center thickness of optical elements and the inter-mirror spacing, often requiring errors to be controlled on the order of micrometers. This extreme sensitivity to tolerances severely restricts the engineering and mass production of high-magnification systems. While reflective systems solve the problems of high-power damage and chromatic aberration, large-aperture mirror assemblies are extremely sensitive to mechanical support structures and environmental temperature changes, which can reduce the alignment accuracy of the optical device.

[0004] Meanwhile, the inherent asymmetry of off-axis aspherical systems makes it difficult for traditional one-time integrated assembly and adjustment methods to guarantee the system's ultra-high precision at the diffraction limit. Furthermore, integrated transceiver systems suffer from error coupling issues. The integrated transceiver design requires the transmitting and receiving optical paths to share a primary mirror group. While saving space, this also makes it easy for tolerance errors in the front-end off-axis mirror group to be directly coupled to the back-end receiving fiber-coupled optical path, making it difficult to correct the overall system performance through localized segment adjustments. Utility Model Content

[0005] One objective of this invention is to provide an off-axis folding-back integrated optical transceiver device, which solves the technical problems of high magnification and large aperture integrated optical transceivers in the prior art, which are difficult to coordinate in terms of tolerance control, thermal stability and assembly accuracy.

[0006] Another objective of this invention is to enhance the overall detection sensitivity and signal-to-noise ratio.

[0007] According to the purpose of this utility model, this utility model provides an off-axis folding transceiver integrated optical device. The optical device is located within a mirror frame and includes a laser, a transmission beam expander system, a transceiver separation module, a plane mirror, a reflection beam expander system, and an optical fiber coupling system located on one side of the transceiver separation module, arranged sequentially along the excitation ray. The reflective surface of the plane mirror faces the transceiver separation module and is at a preset angle to the excitation ray, so that the excitation ray passing through the transceiver separation module is reflected to the reflection beam expander system. This makes the optical path between the laser and the plane mirror perpendicular to the optical path between the plane mirror and the reflection beam expander system, thereby achieving a beam expansion ratio greater than or equal to 30X. The reflection beam expanding system includes an off-axis convex mirror that can form a parallel beam with the plane mirror and an off-axis concave mirror for emitting the excitation light and receiving the reflected light. The off-axis convex mirror and the off-axis concave mirror are confocal and have no real focal point in the optical path. The output aperture of the reflection beam expanding system is greater than or equal to 250 mm. The fiber optic coupling system includes a converging lens and a receiving fiber located at the end of the converging lens away from the transceiver separation module, such that the reflected light passes sequentially through the off-axis concave mirror, the off-axis convex mirror, the plane mirror, and the transceiver separation module, and is coupled to the receiving fiber through the converging lens. The transmission beam expansion system, the fiber optic coupling system, and the reflection beam expansion system are segmented and adjusted using a parallel flat crystal to achieve magnification beam expansion.

[0008] Optionally, the coefficient of linear expansion of the frame material is less than 5 × 10⁻⁶. -6 / K.

[0009] Optionally, the reflectivity of the detection wavelength of the reflection beam expander system is greater than 50%.

[0010] Optionally, the transceiver separation module further includes: Polarization beam splitter; A quarter-wave plate is located between the polarizing beam splitter and the plane mirror.

[0011] Optionally, the Airy disk diameter of the converging lens is smaller than the core diameter of the receiving optical fiber.

[0012] Optionally, the transmission beam expanding system includes a first lens, a second lens, and a third lens arranged at intervals, wherein the first lens, the second lens, and the third lens are all quartz lenses.

[0013] Optionally, the receiving optical fiber is a single-mode optical fiber with a core diameter of less than or equal to 10 μm.

[0014] Optionally, the wavefront error RMS of the optical device is less than or equal to λ / 20@1064nm.

[0015] This invention achieves an optical system with high beam magnification, large aperture output, low wavefront error, and compact integrated transceiver structure by adopting an off-axis folding optical path, a dual-stage beam expander structure, and a segmented assembly and adjustment strategy. It effectively solves the problems of traditional high-magnification beam expander systems, such as difficulty in reducing divergence angle, sensitivity to assembly and adjustment tolerances, and wavefront distortion caused by temperature drift, thereby significantly improving the system's long-distance detection performance and engineering feasibility.

[0016] Furthermore, the reflectivity of the detection wavelength of the present invention's reflection beam expander system is greater than 50%, which can effectively reduce optical path loss and improve the energy utilization rate after beam expansion. This allows the system to maintain sufficient optical power output under large-aperture, long-distance transmission conditions. At the same time, the improved reflection efficiency helps to enhance the optical device's ability to collect echo signals and improve the overall detection sensitivity and signal-to-noise ratio.

[0017] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic structural diagram of an optical device according to an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a transmission beam expander system according to an embodiment of the present invention; Figure 3 This is a schematic structural diagram of a reflection beam expander system according to an embodiment of the present invention; Figure 4 This is a schematic structural diagram of an optical fiber coupling system according to an embodiment of the present invention; Figure 5 This is a schematic assembly structure diagram of an optical device according to an embodiment of the present invention.

[0019] Figure label: 100 - Optical device; 10 - Laser; 20 - Transmission beam expander system; 21 - First lens; 22 - Second lens; 23 - Third lens; 30 - Transmitter / receiver separation module; 31 - Polarization beam splitter; 32 - Quarter-wave plate; 40 - Plane mirror; 41 - Reflecting surface; 50 - Reflection beam expander system; 51 - Off-axis convex mirror; 52 - Off-axis concave mirror; 60 - Fiber optic coupling system; 61 - Converging lens; 62 - Receiving fiber; 70 - Parallel flat crystal; 80 - First inspection mirror; 90 - Second inspection mirror. Detailed Implementation

[0020] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0022] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] Figure 1 This is a schematic structural diagram of an optical device according to an embodiment of the present invention. Figure 2 This is a schematic structural diagram of a transmission beam expander system according to an embodiment of the present invention. Figure 3 This is a schematic structural diagram of a reflection beam expander system according to an embodiment of the present invention. Figure 4This is a schematic structural diagram of an optical fiber coupling system according to an embodiment of the present invention. Figure 5 This is a schematic assembly structure diagram of an optical device according to an embodiment of the present invention.

[0025] like Figure 1 As shown, this utility model provides an off-axis folding transceiver integrated optical device 100 for use in the 1064nm working band. The optical device 100 is located within a frame and includes a laser 10, a transmission beam expander 20, a transceiver separation module 30, a plane mirror 40, a reflection beam expander 50, and an optical fiber coupling system 60 located on one side of the transceiver separation module 30, arranged sequentially along the excitation beam. The reflective surface 41 of the plane mirror 40 faces the transceiver separation module 30 and is at a preset angle to the excitation beam, so that the excitation beam passing through the transceiver separation module 30 is reflected to the reflection beam expander 50. This makes the optical path between the laser 10 and the plane mirror 40 perpendicular to the optical path between the plane mirror 40 and the reflection beam expander 50, i.e., an L-shaped optical path is formed inside the optical device 100 to achieve beam expansion with a magnification greater than or equal to 30X. The reflection beam expander 50 includes an off-axis convex mirror 51 that can form a parallel beam with the plane mirror 40 and an off-axis concave mirror 52 for emitting the excitation beam and receiving the reflected beam (see reference). Figure 3 The off-axis convex mirror 51 and off-axis concave mirror 52 are confocal and have no real focal point in the optical path. The output aperture of the reflection beam expander system 50 is greater than or equal to 250mm. The fiber optic coupling system 60 includes a converging lens 61 and a receiving fiber 62 located at the end of the converging lens 61 away from the transceiver separation module 30, so that the reflected light passes sequentially through the off-axis concave mirror 52, the off-axis convex mirror 51, the plane mirror 40, and the transceiver separation module 30, and is coupled to the receiving fiber 62 through the converging lens 61. The transmission beam expander system 20, the fiber optic coupling system 60, and the reflection beam expander system 50 are connected by a parallel flat crystal 70 (see reference). Figure 5 The lens is assembled and adjusted in segments to achieve magnification expansion; the linear expansion coefficient of the frame material is less than 5 × 10⁻⁶. -6 / K.

[0026] In this embodiment, by adopting an off-axis folding optical path, a dual-stage beam expander structure, and a segmented assembly and adjustment strategy, an optical system with high beam expansion ratio, large aperture output, low wavefront error, and a compact integrated transceiver structure is realized. This effectively solves the problems of traditional high-magnification beam expander systems, such as difficulty in reducing divergence angle, sensitivity to assembly and adjustment tolerances, and wavefront distortion caused by temperature drift, thereby significantly improving the system's long-distance detection performance and engineering feasibility.

[0027] In this embodiment, the off-axis folding transceiver integrated optical device 100 uses a two-stage hybrid optical path structure of transmission-type beam expander and off-axis aspherical reflection beam expander to achieve a total beam expansion ratio of ≥30X while significantly reducing the dependence on the micron-level tolerance of the single-stage system. This enables beam expansion capabilities with low assembly and adjustment difficulty and high engineering feasibility even under high magnification conditions. Furthermore, by adopting a confocal but non-real focal point reflective structure of off-axis concave / convex dual-reflector system, it avoids energy accumulation of high-power laser at the focal point, significantly improving the resistance to laser damage and ensuring high wavefront quality emission. The output aperture reaches ≥250mm, which can meet the low divergence angle emission requirements of long-range lidar.

[0028] In this embodiment, a folded L-shaped optical path geometry decoupling design is introduced, and the linear expansion coefficient of the frame material is less than 5×10. -6 / K significantly reduces structural dimensional shifts caused by temperature changes, ensuring the stability of the optical device 100's assembly and optical axis orientation under environmental fluctuations. This reduces system aberration growth, guarantees wavefront quality, and improves long-distance transmission and reception accuracy. Simultaneously, it effectively isolates the propagation of thermal deformation from the front end of the off-axis mirror assembly to the rear fiber coupling path, ensuring that temperature changes only cause overall spot shift rather than wavefront degradation. This allows the system to maintain a stable wavefront quality of RMS≤λ / 20 within the 20℃-30℃ range, significantly improving the system's environmental adaptability and reliability.

[0029] In this embodiment, the complex high-magnification aspherical dual-reflective system calibration process is broken down into two parts: pre-stage transmission beam expansion calibration and post-stage reflection beam expansion calibration. This makes the calibration process repeatable and reversible, greatly reducing the failure rate and cost of calibration.

[0030] In a further embodiment, the reflectivity of the detection wavelength of the reflection beam expander system 50 is greater than 50%, which can effectively reduce optical path loss and improve the energy utilization rate after beam expansion. This allows the system to maintain sufficient optical power output under large aperture and long-distance transmission conditions. At the same time, the improved reflection efficiency helps to enhance the optical device 100's ability to collect echo signals and improve the overall detection sensitivity and signal-to-noise ratio.

[0031] like Figure 1As shown, in a further embodiment, the transceiver separation module 30 further includes a polarization beamsplitter 31 and a quarter-wave plate 32, with the quarter-wave plate 32 disposed between the polarization beamsplitter 31 and the plane mirror 40. In this embodiment, by setting a polarization beamsplitter 31 in the transceiver separation module 30 and adding a quarter-wave plate 32 between the polarization beamsplitter 31 and the plane mirror 40, the emitted light achieves polarization state rotation in the round-trip optical path, so that the polarization beamsplitter 31 can effectively distinguish between the emitted light and the echo signal, thereby achieving efficient separation of the transceiver optical path and improving the light transmission efficiency and detection sensitivity of the echo signal.

[0032] In a further embodiment, the Airy disk diameter of the converging lens 61 is smaller than the core diameter of the receiving fiber 62, so that the main energy distribution of the echo light falls completely within the effective light-receiving area of ​​the fiber, thereby improving the fiber coupling efficiency, reducing coupling loss, and enhancing the ability to acquire weak echo signals.

[0033] like Figure 2 As shown, in a further embodiment, the transmission beam expander system 20 includes a first lens 21, a second lens 22, and a third lens 23 arranged at intervals. The first lens 21, the second lens 22, and the third lens 23 are all quartz lenses, which makes the transmission beam expander system 20 have a lower absorption rate and thermal lensing effect in the 1064nm working band, and has excellent refractive index stability and chromatic aberration control capability, thereby improving the wavefront quality and environmental adaptability of the beam expander optical path, and achieving a stable beam expansion ratio and output beam shape under high power incident conditions.

[0034] like Figure 4 As shown, in a further embodiment, the receiving fiber 62 is a single-mode fiber with a core diameter less than or equal to 10 μm, allowing only the fundamental mode to transmit during echo beam coupling. This significantly improves beam mode purity and signal stability, reducing detection errors caused by higher-order mode noise and mode distortion. Simultaneously, it reduces transmission loss caused by uneven electric field distribution on the coupling surface, improves the echo light reception signal-to-noise ratio, and enhances the target echo detection sensitivity of long-range lidar.

[0035] The technical solution of this application will be further described below with reference to specific embodiments.

[0036] Example 1

[0037] The frame of the off-axis folding transceiver integrated optical device 100 is made of Invar steel. The first lens 21, the second lens 22, and the third lens 23 of the transmission beam expander system 20 are quartz lenses. The off-axis convex parabolic reflector 51 of the reflection beam expander system 50 has a 14X incident end with a vertex radius of curvature of 60 mm and an off-axis amount of 13 mm. The off-axis concave reflector 52 has a 14X beam expander exit end with a vertex radius of curvature of 840 mm and an off-axis amount of 182 mm. The converging lens 61 of the fiber coupling system 60 has a focal length of 40 mm and an Airy disk diameter of 5.76 μm, and is finally coupled into a single-mode receiving fiber 62 with a core diameter of 6.6 μm. The operating wavelength λ2 is 1064.42 nm, the total beam expansion ratio is 42X, which is composed of a 3X transmission beam expander and a 14X off-axis reflection beam expander connected in series, and the final output parallel beam has a aperture of 252 mm.

[0038] In summary, the above-mentioned assembly and adjustment method forms a complete assembly and adjustment closed loop through chromatic aberration compensation, parallel flat crystal 70 decoupling, five-degree-of-freedom trimming compensation, and real-time interference feedback. It breaks through the limitation of traditional off-axis large-aperture systems that are difficult to achieve precise joint adjustment. This allows the device to stably obtain low wavefront error and high fiber coupling efficiency under high beam expansion ratio (≥30X) and large aperture (≥250mm) conditions, greatly improving the feasibility of system engineering, assembly and adjustment convergence speed, and environmental adaptability.

[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An off-axis folding transceiver integrated optical device, characterized in that, The optical device is located within a frame and includes a laser, a transmission beam expander, a transceiver separation module, a plane mirror, a reflection beam expander, and an optical fiber coupling system located on one side of the transceiver separation module, arranged sequentially along the excitation ray. The reflective surface of the plane mirror faces the transceiver separation module and is at a preset angle to the excitation ray, so that the excitation ray passing through the transceiver separation module is reflected to the reflection beam expander, making the optical path between the laser and the plane mirror perpendicular to the optical path between the plane mirror and the reflection beam expander, thereby achieving a beam expansion ratio greater than or equal to 30X. The reflection beam expanding system includes an off-axis convex mirror that can form a parallel beam with the plane mirror and an off-axis concave mirror for emitting the excitation light and receiving the reflected light. The off-axis convex mirror and the off-axis concave mirror are confocal and have no real focal point in the optical path. The output aperture of the reflection beam expanding system is greater than or equal to 250 mm. The fiber optic coupling system includes a converging lens and a receiving fiber located at the end of the converging lens away from the transceiver separation module, such that the reflected light passes sequentially through the off-axis concave mirror, the off-axis convex mirror, the plane mirror, and the transceiver separation module, and is coupled to the receiving fiber through the converging lens. The transmission beam expanding system, the fiber optic coupling system, and the reflection beam expanding system are segmented and adjusted using a parallel flat crystal.

2. The optical device according to claim 1, characterized in that, The linear expansion coefficient of the frame is less than 5 × 10⁻⁶. -6 / K.

3. The optical device according to claim 2, characterized in that, The reflectivity of the detection wavelength of the reflection beam expander system is greater than 50%.

4. The optical device according to claim 3, characterized in that, The transceiver separation module also includes: Polarization beam splitter; A quarter-wave plate is located between the polarizing beam splitter and the plane mirror.

5. The optical device according to claim 4, characterized in that, The Airy disk diameter of the converging lens is smaller than the core diameter of the receiving optical fiber.

6. The optical device according to claim 5, characterized in that, The transmission beam expanding system includes a first lens, a second lens, and a third lens arranged at intervals, wherein the first lens, the second lens, and the third lens are all quartz lenses.

7. The optical device according to claim 6, characterized in that, The receiving optical fiber is a single-mode optical fiber with a core diameter of less than or equal to 10 μm.

8. The optical device according to any one of claims 1-7, characterized in that, The wavefront error RMS of the optical device is less than or equal to λ / 20@1064nm.

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