High-power optical isolator

Abstract

The utility model discloses a high-power optical isolator, which comprises a magnetic ring, a first diffraction lens, a second diffraction lens, a first wedge-shaped birefringent crystal, a second wedge-shaped birefringent crystal and a dynamic adjustable wedge-shaped angle, accurate matching and regulation of incident light with different wavelengths and powers can be achieved, the bearing capacity of the optical isolator for high-power laser is improved, all optical elements are fixed through optical cement, the problem that traditional organic cement loses efficacy due to the influence of high temperature and strong light is avoided, the stability of the optical isolator is ensured, and the service life of the optical isolator is prolonged. The dynamic adjustable wedge-shaped angle is finely adjusted through piezoelectric ceramics, the precision and stability of the optical isolator are improved, the surfaces of the first diffraction lens and the second diffraction lens are plated with aluminum nitride heat conduction layers, and micron-sized cooling flow channels are embedded, so that the temperature of an optical element is effectively reduced, and performance reduction or damage caused by overheating is prevented; and the service life of the optical isolator is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of optical communication and lidar technology, specifically a high-power optical isolator. Background Technology

[0002] Optical isolators are mainly used to ensure the unidirectionality of optical signals during transmission and to prevent reverse optical signals from interfering with or damaging the system. Traditional optical isolators usually use a sandwich structure consisting of a polarizer, a Faraday rotator, and polarized light, and the optical components are bonded and fixed together with organic adhesive.

[0003] However, with the rapid development of communication and lidar technologies, the requirements for laser output power are becoming increasingly higher. Traditional optical isolators have gradually revealed some problems. First, when the energy of the beam passing through the isolator is too high, the organic adhesive may fail due to the inability to withstand the effects of high temperature and strong light, resulting in a decrease in the stability and reliability of the isolator. Second, the polarizer is an absorption device for light whose polarization state does not match the polarization state of the polarizer. Due to the limitations of the process and application conditions during the assembly of the polarizer, it is impossible to guarantee that the polarizer's inherent polarization state matches the polarization state of the incident light 100%. When the energy of the beam passing through the polarizer is too high, the polarizer is easily damaged due to absorbing too much energy. Therefore, we need to propose a high-power optical isolator. Utility Model Content

[0004] The purpose of this invention is to provide a high-power optical isolator. By employing a first wedge-shaped birefringent crystal and a second wedge-shaped birefringent crystal with a yttrium vanadate and α-BBO crystal composite structure, as well as a dynamically adjustable wedge angle design, this invention effectively solves the problems of easy damage and reliability failure of traditional optical isolators when subjected to high-power lasers, thereby addressing the issues raised in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A high-power optical isolator includes: a magnetic ring; a first diffractive lens and a second diffractive lens; a first wedge-shaped birefringent crystal and a second wedge-shaped birefringent crystal, both of which adopt a composite structure of yttrium vanadate and α-BBO crystal, and have dynamically adjustable wedge angles on their end faces, with the angles finely adjusted by piezoelectric ceramics; a Faraday sheet; and optical elements fixed by optical adhesive; the surfaces of the first and second diffractive lenses are coated with an aluminum nitride thermal conductive layer and embedded with micron-level cooling channels.

[0007] Preferably, the magnetic ring has an embedded non-contact Hall sensor and adopts a segmented assembly structure, and the magnetic poles of the magnetic ring can be detached and their orientation adjusted.

[0008] Preferably, a polarization compensation mirror is provided behind the second wedge-shaped birefringent crystal, the polarization compensation mirror being composed of a λ / 4 waveplate and a high-reflectivity mirror.

[0009] Preferably, the Faraday plate has a built-in magnetic pole structure and integrates a permanent magnet to replace the external magnetic ring.

[0010] Preferably, the width of the micron-level cooling channel is 50-80 μm, and the circulating cooling medium is deionized water.

[0011] Preferably, the control range of the dynamically adjustable wedge angle is 3°-8°, which is suitable for input light with wavelengths of 400-1600nm.

[0012] Preferably, the polarization compensation mirror has a reverse isolation of ≥55dB and a reverse light failure probability of <10%. -6 .

[0013] Preferably, the Hall sensor has a magnetic field strength monitoring accuracy of ±1%, and the magnetic saturation state of the Faraday plate is adjusted in real time through a feedback circuit.

[0014] Preferably, the second diffraction lens can be omitted, and the forward combined beam is emitted directly.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. This utility model, by employing a first wedge-shaped birefringent crystal and a second wedge-shaped birefringent crystal with a composite structure of yttrium vanadate and α-BBO crystal, as well as a dynamically adjustable wedge angle design, can achieve precise matching and control of incident light of different wavelengths and powers, thereby effectively improving the optical isolator's ability to withstand high-power lasers.

[0017] 2. In this invention, each optical element is fixed with optical adhesive, avoiding the failure of traditional organic adhesives due to high temperature and strong light, thus ensuring the stability and reliability of the optical isolator. At the same time, the dynamically adjustable wedge angle is finely adjusted through piezoelectric ceramics, further improving the accuracy and stability of the optical isolator. The surfaces of the first and second diffractive lenses are coated with aluminum nitride thermal conductive layers and embedded with micron-level cooling channels, which can effectively reduce the temperature of the optical elements, prevent performance degradation or damage due to overheating, and thus extend the service life of the optical isolator. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the first diffractive lens and the aluminum nitride thermal conductive layer of this utility model;

[0020] Figure 3This is a schematic diagram of the structure of the second wedge-shaped birefringent crystal and polarization compensation mirror of this utility model.

[0021] In the figure: 1. Magnetic ring; 2. First diffraction lens; 3. Second diffraction lens; 4. First wedge-shaped birefringent crystal; 5. Second wedge-shaped birefringent crystal; 6. Dynamically adjustable wedge angle; 7. Faraday sheet; 8. Aluminum nitride thermal conductive layer; 9. Piezoelectric ceramic; 10. Polarization compensation mirror. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figure 1-3 This utility model provides a technical solution:

[0024] A high-power optical isolator includes: a magnetic ring 1; a first diffraction lens 2 and a second diffraction lens 3;

[0025] The first wedge-shaped birefringent crystal 4 and the second wedge-shaped birefringent crystal 5 both adopt a composite structure of yttrium vanadate and α-BBO crystal, and the end face is provided with a dynamically adjustable wedge angle 6. By adopting the first wedge-shaped birefringent crystal 4 and the second wedge-shaped birefringent crystal 5 with a composite structure of yttrium vanadate and α-BBO crystal, and the design of the dynamically adjustable wedge angle 6, it is possible to achieve precise matching and control of incident light of different wavelengths and powers, thereby effectively improving the optical isolator's ability to withstand high-power lasers.

[0026] The angle is finely adjusted using piezoelectric ceramic 9; Faraday film 7; each optical element is fixed with optical adhesive, avoiding the failure of traditional organic adhesives due to high temperature and strong light, ensuring the stability and reliability of the optical isolator. At the same time, the dynamically adjustable wedge angle 6 is finely adjusted using piezoelectric ceramic 9, further improving the accuracy and stability of the optical isolator; the surfaces of the first diffraction lens 2 and the second diffraction lens 3 are coated with aluminum nitride thermal conductive layer 8 and embedded with micron-level cooling channels, which can effectively reduce the temperature of the optical elements, prevent performance degradation or damage due to overheating, and thus extend the service life of the optical isolator.

[0027] The magnetic ring 1 incorporates a non-contact Hall sensor and adopts a segmented assembly structure. The magnetic poles of the magnetic ring 1 are detachable and their orientation can be adjusted. This magnetic ring not only provides the necessary magnetic field environment for the Faraday plate but also utilizes an embedded non-contact Hall sensor design, enabling precise monitoring of the magnetic field strength with an accuracy of ±1%. The Hall sensor adjusts the magnetic saturation state of the Faraday plate 7 in real time through a feedback circuit, ensuring the stable performance of the optical isolator under different operating conditions. The magnetic ring 1, with its segmented assembly structure, consists of multiple arc-shaped magnetic blocks. Each block is connected to adjacent blocks via precision slots, supporting rapid disassembly and reassembly. The magnetic pole orientation (NS or SN) can be adjusted by rotating the magnetic blocks, adapting to the polarization management requirements of different lasers.

[0028] A polarization compensation mirror 10 is installed behind the second wedge-shaped birefringent crystal 5. The polarization compensation mirror 10 is composed of a λ / 4 waveplate and a high-reflectivity mirror. This design effectively compensates for polarization state shifts caused by system errors or environmental changes, improves the reverse isolation of the optical isolator (≥55dB), and reduces the probability of reverse light failure (<10). -6 The polarization-compensated reflector ensures the reliability of the equipment in high-precision applications;

[0029] The Faraday plate 7 has a built-in magnetic pole structure, integrating a permanent magnet to replace the external magnetic ring. This design not only simplifies the structure of the optical isolator, but also improves the reliability and stability of the device. Due to the presence of the permanent magnet, the Faraday plate can achieve the Faraday rotation effect without the assistance of an external magnetic field, reducing the dependence on external devices. The Faraday plate with built-in magnetic poles makes the optical isolator more compact and efficient, and reduces manufacturing costs.

[0030] The micron-level cooling channel width is 50-80μm, and the circulating cooling medium is deionized water. The first diffraction lens 2 and the second diffraction lens 3 are not only responsible for the collimation and focusing of the beam, but also have an aluminum nitride thermal conductive layer 8 coated on their surface and embedded with a micron-level (50-80μm) cooling channel. This design effectively improves the heat dissipation efficiency of the lens and prevents performance degradation caused by high temperature. The use of deionized water as the circulating cooling medium ensures the stability and long life of the cooling system. Through this cooling mechanism, the optical isolator can maintain stable performance output under high power operating conditions and extend the service life of the equipment.

[0031] The dynamically adjustable wedge angle 6 has a control range of 3°-8°, adapting to input light wavelengths of 400-1600nm;

[0032] The Hall sensor has a magnetic field strength monitoring accuracy of ±1%, and the magnetic saturation state of the Faraday plate 7 is adjusted in real time through a feedback circuit.

[0033] The second diffraction lens 3 can be omitted, allowing the forward-beamed light to exit directly. Depending on the specific application requirements, the second diffraction lens 3 can be omitted, allowing the forward-beamed light to exit directly. This design flexibility allows the optical isolator to adapt to different application scenarios, especially in situations where space is limited or the optical path needs to be simplified. The optional design of the second diffraction lens improves the versatility and practicality of the optical isolator, enabling users to configure it flexibly according to their actual needs.

[0034] Example 1: Application of Precision Optical Isolation in High-Power Laser Communication Systems

[0035] Application scenarios:

[0036] The high-power laser transmitter used in deep-sea fiber optic communication nodes must withstand 50W of continuous laser light (wavelength 1550nm) and meet the stability requirements of extreme environments ranging from -40℃ to +85℃.

[0037] Dynamic wedge angle control: The dynamically adjustable wedge angle 6 of the first / second wedge birefringent crystal (4,5) is set to 5.2°, and the ±0.3° real-time fine adjustment is achieved through the piezoelectric ceramic 9 to match the polarization extinction ratio (PER) of 1550nm laser >40dB.

[0038] Intelligent compensation of magnetic ring: Magnetic ring 1 is assembled from 12 arc-shaped magnetic blocks. The magnetic field strength is monitored in real time by a Hall sensor. When the temperature drift causes the magnetic field strength to decrease by 1.2%, the feedback circuit automatically increases the magnetic saturation of Faraday plate 7 by 8% to maintain a constant rotation angle.

[0039] Dual-lens cascaded heat dissipation: The thickness of the aluminum nitride thermally conductive layer 8 on the surfaces of the first diffractive lens 2 and the second diffractive lens 3 is optimized to 12μm, and the flow rate of deionized water in the micron-level cooling channel is set to 0.8m / s, achieving 80W / cm² heat dissipation. 2 Temperature rise at heat flux density ≤ 5℃.

[0040] Example 2: Damage-resistant optical isolation scheme for high-energy lidar transmitting systems

[0041] Application scenarios:

[0042] The airborne lidar transmitting module needs to process pulsed lasers with a peak power of 200W and a pulse width of 10ns (wavelength 1064nm), and requires a reverse light isolation of ≥60dB.

[0043] Crystal composite structure reinforcement: The first / second wedge-shaped birefringent crystals (4,5) are composites of yttrium vanadate (YVO4) and α-BBO in a 3:1 thickness ratio. The thickness of the YVO4 layer is optimized to 2.1 mm, and the laser damage resistance threshold is improved to 15 J / cm. 2 (1064nm, 10ns).

[0044] The polarization compensation mirror 10 is optimized as follows: the λ / 4 waveplate adopts a double-layer magnesium fluoride (MgF2) coating, the phase delay error is controlled within ±1.2°, the surface roughness of the high reflectivity mirror Ra<0.3nm, and the reverse isolation is 60.2dB.

[0045] Rapid magnetic pole reconfiguration technology: The magnetic ring 1 adopts a magnetic quick-release structure, which can complete the exchange of N and S poles within 15 seconds, adapting to laser emission sources with different polarization states.

[0046] Example 3: Integrated Optical Isolation Module for Compact Industrial Laser Processing Heads

[0047] Application scenarios:

[0048] The fiber laser cutting head is internally integrated and requires an external dimension of ≤Φ50mm×80mm. It must also withstand a 2kW continuous laser (wavelength 1070nm) and be compatible with fiber collimators from different manufacturers.

[0049] Simplified single-lens design: The second diffraction lens 3 is omitted, and the first diffraction lens 2 adopts an aspherical design, increasing the NA value to 0.25. Combined with the dynamically adjustable wedge angle 6 with a range of 3°-8°, it can directly interface with fiber optic collimators from 10 mainstream manufacturers.

[0050] Miniaturized magnetic ring design: Magnetic ring 1 is assembled from 8 miniature magnetic blocks, with the outer diameter compressed to 45mm. The sampling frequency of the built-in Hall sensor is increased to 10kHz, ensuring that the dynamic magnetic field adjustment response time is <50μs.

[0051] Dual-channel cooling system: The cooling channel of the first diffraction lens 2 adopts a double-helix structure with a gradient change in the cross-sectional area of ​​the channel (inlet 80μm → outlet 50μm), and maintains a temperature rise of ≤8℃ under 2kW laser input.

[0052] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high power optical isolator, characterized by, include: Magnetic ring (1); First diffraction lens (2) and second diffraction lens (3); The first wedge-shaped birefringent crystal (4) and the second wedge-shaped birefringent crystal (5) both adopt a composite structure of yttrium vanadate and α-BBO crystal, and the end face is provided with a dynamically adjustable wedge angle (6), which is finely adjusted by piezoelectric ceramic (9); Faraday film (7); Each optical component is fixed with optical adhesive; The first diffractive lens (2) and the second diffractive lens (3) are coated with an aluminum nitride thermal conductive layer (8) and embedded with micron-level cooling channels.

2. A high power optical isolator as claimed in claim 1, characterized in that: The magnetic ring (1) has a non-contact Hall sensor embedded in it and adopts a segmented assembly structure. The magnetic poles of the magnetic ring (1) can be detached and their orientation adjusted.

3. A high power optical isolator as claimed in claim 1, wherein: A polarization compensation mirror (10) is provided behind the second wedge-shaped birefringent crystal (5), which is composed of a λ / 4 waveplate and a high-reflectivity mirror.

4. A high power optical isolator as claimed in claim 1, wherein: The Faraday plate (7) has a built-in magnetic pole structure and integrates a permanent magnet to replace the external magnetic ring.

5. A high-power optical isolator according to claim 1, characterized in that: The width of the micron-level cooling channel is 50-80μm, and the circulating cooling medium is deionized water.

6. A high power optical isolator as claimed in claim 1, wherein: The control range of the dynamically adjustable wedge angle (6) is 3°-8°, which is suitable for input light with wavelengths of 400-1600nm.

7. A high power optical isolator as claimed in claim 3, wherein: The reverse isolation of the polarization compensating mirror (10) is greater than or equal to 55 dB, and the reverse light failure probability is less than 10 -6 .

8. A high power optical isolator as claimed in claim 2, wherein: The Hall sensor has a magnetic field strength monitoring accuracy of ±1%, and the magnetic saturation state of the Faraday plate (7) is adjusted in real time through a feedback circuit.

9. A high power optical isolator as claimed in claim 1, wherein: The second diffraction lens (3) can be omitted, and the positive beam of the combined beam is emitted directly.

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