An online high-precision optical isolator based on a Faraday rotator

Abstract

The application discloses an online high-precision optical isolator based on a Faraday rotator and relates to the technical field of optical isolation, which comprises a mounting seat and a temperature compensation mechanism, the temperature compensation mechanism is arranged on the inner side of the mounting seat, the temperature compensation mechanism comprises a magnetic force compensation coil, a thermistor, a slit, a convex lens and a photodiode module, the magnetic force compensation coil is arranged on the outer side of the thermistor, the slit is located at the bottom of the convex lens, the photodiode module is located at the top of the convex lens, the thermistor is used for detecting temperature changes in real time, ensuring the stability of the magnetic field and the position of the light path, and the baffle cooperates with the slit, the reflecting mirror, the convex lens and the photodiode module, the optical rotation angle drift is fed back through the change of the light intensity, the closed-loop adjustment of the magnetic field and the secondary correction are realized, the optical rotation precision and the working stability of the optical isolator under the temperature difference environment are improved, and the transmission of normal optical signals is ensured.

Description

Technical Field

[0001] This invention relates to the field of optical isolation technology, specifically to an online high-precision optical isolation device based on a Faraday rotator. Background Technology

[0002] A Faraday rotator is a magneto-optical device that works using the Faraday effect. Under the influence of a magnetic field, when linearly polarized light passes through a magneto-optical medium, its polarization plane rotates unidirectionally with the direction of propagation. Its core characteristic is non-reciprocity; the polarization plane rotates in opposite directions when the light propagates in the forward and reverse directions. It is often used to isolate reflected light and stabilize the polarization state of the optical path, and is a core component of optical isolators and circulators.

[0003] An optical isolator is a non-reciprocal optical device based on the Faraday effect. It allows light waves to pass through in only one direction while attenuating and isolating light transmitted in the opposite direction. It uses a magneto-optical medium to rotate the polarization planes of the forward and reverse light in an directional manner. Combined with a polarizer and an analyzer, it allows the forward signal light to pass through smoothly while blocking reflected and backscattered light, thereby protecting the front-end light source and optical path system from interference and ensuring the stable operation of the optical transmission system.

[0004] However, the existing online high-precision optical isolation device based on a Faraday rotator has the following shortcomings: Currently available online high-precision optical isolation devices based on Faraday rotators achieve ultra-low insertion loss and ultra-high reverse isolation through high-purity magneto-optical crystals and precise magnetic field control. However, in extreme environments with large temperature differences, the optical rotation angle of the magneto-optical medium drifts significantly with temperature due to the large diurnal temperature range. Existing structures mostly rely on passive heat dissipation and simple temperature patching for compensation, which cannot dynamically match the magnetic field strength and optical rotation characteristics in real time. This leads to problems such as isolation fluctuations and polarization state degradation, making it difficult to maintain stable optical path transmission performance over a wide temperature range and affecting the transmission of normal optical signals.

[0005] Therefore, this invention proposes an online high-precision optical isolation device based on a Faraday rotator to solve the problems mentioned above. Summary of the Invention

[0006] The purpose of this invention is to provide an online high-precision optical isolator based on a Faraday rotator, and to provide an optical isolator resistant to temperature drift. This invention solves the problem of optical rotation angle deviation caused by magnetic force reduction in traditional optical isolators in environments with large temperature differences. It achieves real-time magnetic field compensation through a thermistor and a magnetic force compensation coil, ensures the stability of the core component position through a fixed structure, and uses an optical path detection component to feedback light intensity changes, accurately reflects optical rotation angle drift, and completes closed-loop adjustment and secondary correction. This improves the working accuracy and operational stability of the optical isolator in complex temperature difference environments, and ensures reliable optical signal transmission.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an online high-precision optical isolation device based on a Faraday rotator, comprising a mounting base and a temperature compensation mechanism, wherein the temperature compensation mechanism is disposed on the inner side of the mounting base; The temperature compensation mechanism includes a magnetic compensation coil, a thermistor, a slit, a convex lens, and a photodiode module. The magnetic compensation coil is located outside the thermistor, the slit is located at the bottom of the convex lens, and the photodiode module is located at the top of the convex lens. The thermistor is used to detect temperature changes in real time. The magnetic compensation coil adjusts the current in real time according to the temperature change difference detected by the thermistor to adaptively provide auxiliary magnetic force. The slit is used to filter the light spot, the convex lens is used to amplify the light spot signal, and the photodiode module is used to verify the changes in the detected light spot and provide secondary real-time detection.

[0008] Preferably, the temperature compensation mechanism further includes a housing, which is installed inside the mounting base. One end of the housing is provided with an input end cylinder, the other end of the input end cylinder is provided with an input end connecting ring, the other end of the input end connecting ring is provided with an input end cap, and the inner side of the input end connecting ring is provided with a timing lens.

[0009] Preferably, a polarizer is installed on the inner side of the input end cylinder, an output end cylinder is installed on the other side of the housing, an output end connecting ring is installed on the other side of the output end cylinder, an output end cap is installed on the other side of the output end connecting ring, a focusing lens is installed on the inner side of the output end connecting ring, and a polarizer is installed on the inner side of the output end cylinder.

[0010] Preferably, a connecting frame is installed on the inner side of the input end cylinder and the detector, a magnetic cylinder fixing half ring is installed on the outer side of the connecting frame, a cylindrical magnet is installed on the inner side of the magnetic cylinder fixing half ring, a limiting collar is installed on the inner side of the cylindrical magnet, the magnetic compensation coil is sleeved on the outer side of the limiting collar, and the magnetic compensation coil is located on the outer side of the Faraday rotating crystal plate.

[0011] Preferably, the thermistor is installed on the inner bottom of the limiting collar, and the output terminal of the thermistor is electrically connected to a power module, which is installed on the bottom of the housing.

[0012] Preferably, the output end of the magnetic compensation coil passes through the limiting sleeve and is electrically connected to the power module. A fixing ring is installed on the outer side of the connecting frame. An optical path slot is opened on the top of the fixing ring. A baffle is installed on the inner side of the fixing ring. There are two slits, which are respectively opened on both sides of the baffle.

[0013] Preferably, a lens holder is installed on the inner side of the fixing ring, and two refractive mirrors are installed on the inner side of the lens holder.

[0014] Preferably, the two refractive mirrors correspond to the two slits respectively, and the optical path slot is located on top of the two refractive mirrors.

[0015] Preferably, the top of the outer casing has a slot, and a convex lens frame is provided inside the slot. The number of convex lenses is two, and the two convex lenses are installed inside the convex lens frame.

[0016] Preferably, the slot is located at the top of the optical path slot and corresponds to the optical path slot, the photodiode module is installed on the top of the housing, and the photodiode module is located at the top of the slot.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention uses a thermistor to monitor temperature and, in conjunction with a magnetic compensation coil, provides real-time compensation for the loss of magnetic force in the cylindrical magnet due to excessive temperature. This solves the problem of optical rotation angle deviation caused by temperature differences. The core components are fixed by a connecting frame and a magnetic cylinder fixing half-ring, ensuring the stability of the magnetic field and optical path position. The baffle and slit, together with a refracting mirror, a convex lens, and a photodiode module, use changes in light intensity to feedback optical rotation angle drift, achieving closed-loop adjustment and secondary correction of the magnetic field. This improves the optical rotation accuracy and operational stability of the optical isolator under temperature difference environments, ensuring the transmission of normal optical signals. Attached Figure Description

[0018] Figure 1 This is a perspective view of the main structure of an online high-precision optical isolation device based on a Faraday rotator according to the present invention. Figure 2 This is a three-dimensional, exploded view of the structure in an online high-precision optical isolation device based on a Faraday rotator according to the present invention. Figure 3 This is a further exploded perspective view of the structure in an online high-precision optical isolation device based on a Faraday rotator according to the present invention; Figure 4 This is a split perspective view of the temperature compensation mechanism in an online high-precision optical isolation device based on a Faraday rotator according to the present invention. Figure 5 for Figure 4 Enlarged view of point A in the middle; Figure 6 for Figure 4 Enlarged view of point B in the middle; Figure 7 for Figure 4 Enlarged view of point C in the middle; Figure 8This is a cross-sectional view of an online high-precision optical isolation device based on a Faraday rotator according to the present invention.

[0019] In the diagram: 1. Mounting base; 2. Temperature compensation mechanism; 201. Housing; 202. Input end cylinder; 203. Input end connecting ring; 204. Input end cap; 205. Timing lens; 206. Polarizer; 207. Output end cylinder; 208. Analyzer; 209. Output end connecting ring; 210. Focusing lens; 211. Output end cap; 212. Power module; 213. Cylindrical magnet; 214. 215. Limiting collar; 216. Faraday crystal plate; 217. Magnetic compensation coil; 218. Thermistor; 219. Connecting frame; 220. Magnetic cylinder fixing half ring; 221. Fixing ring; 222. Optical path slot; 223. Baffle; 224. Slit; 225. Lens fixing frame; 226. Refracting mirror; 227. Groove; 228. Convex lens; 229. Photodiode module. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1, according to Figure 1 - Figure 5As shown, an online high-precision optical isolation device based on a Faraday rotator includes a mounting base 1 and a temperature compensation mechanism 2. The temperature compensation mechanism 2 is disposed inside the mounting base 1 and includes a magnetic compensation coil 216, a thermistor 217, a slit 223, a convex lens 228, and a photodiode module 229. The magnetic compensation coil 216 is disposed outside the thermistor 217, the slit 223 is located at the bottom of the convex lens 228, and the photodiode module 229 is located at the top of the convex lens 228. The thermistor 217 is used to detect temperature changes in real time. The force compensation coil 216 adjusts its current in real time based on the temperature difference detected by the thermistor 217, providing adaptive auxiliary magnetic force. The slit 223 is used to sieve the light spot, the convex lens 228 amplifies the light spot signal, and the photodiode module 229 verifies the changes in the detected light spot, providing secondary real-time detection. The temperature compensation mechanism 2 also includes a housing 201, which is installed inside the mounting base 1. One end of the housing 201 is fitted with an input end cylinder 202, and the other end of the input end cylinder 202 is fitted with an input end connecting ring 203. On the other side of the housing 201, an input end cap 204 is installed. A timing lens 205 is installed inside the input end connecting ring 203. A polarizer 206 is installed inside the input end cylinder 202. On the other side of the housing 201, an output end cylinder 207 is installed. On the other side of the output end cylinder 207, an output end connecting ring 209 is installed. On the other side of the output end connecting ring 209, an output end cap 211 is installed. A focusing lens 210 is installed inside the output end connecting ring 209. An analyzer 208 is installed inside the output end cylinder 207. The adjacent inner sides of the input end cylinder 202 and the analyzer 208... A connecting frame 218 is installed. A magnetic cylinder fixing half ring 219 is installed on the outside of the connecting frame 218. A cylindrical magnet 213 is installed on the inside of the magnetic cylinder fixing half ring 219. A limiting collar 214 is installed on the inside of the cylindrical magnet 213. A magnetic compensation coil 216 is sleeved on the outside of the limiting collar 214. The magnetic compensation coil 216 is located on the outside of the Faraday rotating crystal plate 215. A thermistor 217 is installed on the bottom inside of the limiting collar 214. The output terminal of the thermistor 217 is electrically connected to a power module 212. The power module 212 is installed on the bottom of the outer casing 201.

[0022] The overall effect of Embodiment 1 is as follows: When traditional optical isolators are applied in environments with large day-night temperature differences, excessively high temperatures will reduce the magnetic force of the module providing magnetic force in the Faraday rotator, thereby weakening the effective magnetic field obtained by the rotating crystal plate, and causing the optical rotation angle to deviate from the 45-degree operating point required by the device. In the application scenario corresponding to this device, when the cylindrical magnet 213 and the Faraday rotating crystal plate 215 are affected by temperature drift, the thermistor 217 on the outer side of the Faraday rotating crystal plate 215 and in the same spatial position monitors the temperature change in real time and estimates the force based on the predicted force. The data is used to compare and calculate the perceived temperature difference in real time. The power module 212 drives the magnetic compensation coil 216 to compensate for the lost magnetic force of the cylindrical magnet 213 in real time. To further verify the accuracy of the compensation and the overall actual angle deviation, the connecting frame 218 fixes the polarizer 206 and the analyzer 208. A magnetic cylinder fixing half ring 219 is installed on the outside of the connecting frame 218 to fix the cylindrical magnet 213, ensuring that the three are in a fixed position. A baffle 222 is set on the inner side of the output end connecting ring 209. The channel inside the baffle 222 ensures that the light spot of the main optical path is normally open. However, the outer part of the baffle 222 blocks the edge-diffusing light and makes the edge light reflect on the surface of the baffle 222. The signal light remains relatively parallel after passing through the collimating lens. The slits 223 on both sides of the baffle 222 allow the light path to reach the surface of the refractor 225. The refractor 225 reflects the signal light to the top. The convex lens 228 amplifies the reflected light signal. The amplified light signal directly contacts the photodiode module 229. The photodiode module 229 reflects the optical rotation angle drift in real time through the change of light intensity. The magnetic compensation coil 216 further controls the current according to the feedback to realize the closed-loop adjustment of the magnetic field. The first compensation result is verified and tested. At the same time, the second and overall adjustments are completed on the basis of the first correction. In the above process, when the temperature is too low, the magnetism of the cylindrical magnet 213 is enhanced. At this time, the voltage polarity at both ends of the coil is freely switched by the drive circuit, thereby changing the current direction to realize the positive superposition and reverse cancellation of the additional magnetic field of the magnetic compensation coil 216, so as to adapt to the optical rotation angle compensation requirements of the cylindrical magnet 213 when it is attenuated at high temperature and enhanced at low temperature.

[0023] Example 2, according to Figure 2 - Figure 8As shown, the output end of the magnetic compensation coil 216 passes through the limiting collar 214 and is electrically connected to the power module 212. A fixing ring 220 is installed on the outer side of the connecting frame 218. An optical path slot 221 is opened on the top of the fixing ring 220. A baffle 222 is installed on the inner side of the fixing ring 220. There are two slits 223, which are respectively opened on both sides of the baffle 222. A lens fixing frame 224 is installed on the inner side of the fixing ring 220. Two refractive mirrors 225 are installed on the inner side of the lens fixing frame 224. 225 corresponds to two slits 223 respectively. The optical path slot 221 is located on the top of the two refractors 225. The top of the housing 201 is provided with a slot 226. A convex lens holder 227 is provided inside the slot 226. There are two convex lenses 228. The two convex lenses 228 are installed inside the convex lens holder 227. The slot 226 is located on the top of the optical path slot 221 and corresponds to the optical path slot 221. The photodiode module 229 is installed on the top of the housing 201. The photodiode module 229 is located on the top of the slot 226.

[0024] The overall effect of Embodiment 2 is as follows: In the above, by reflecting the detected light upward through the refracting mirror 225, and in conjunction with the top convex lens 228 and the photodiode module 229, the detection components are radially arranged without increasing the overall axial length of the optical isolator. While amplifying the optical signal, it is conducive to miniaturization and high-density integration. By adapting to dynamic temperature changes, temperature detection and light intensity detection are performed simultaneously, and current adjustment responds in real time without the need for shutdown calibration. It can maintain a stable optical rotation angle under conditions of continuous temperature difference changes between day and night and rapid fluctuations in ambient temperature, and has a wider working range across the entire temperature range. The magnetic compensation coil 216 increases magnetization in the positive direction and weakens magnetization in the reverse direction according to the temperature, compensates for magnetic field attenuation at high temperatures, and suppresses excessive magnetic field at low temperatures, achieving stable control of the optical rotation angle across the entire temperature range from high to low temperatures. The connecting frame 218, the magnetic cylinder fixing half ring 219, the baffle 222, the refracting mirror 225, the convex lens 228, and related optical components are all modular structures, with clear positioning and simple assembly, which is conducive to mass production and consistency control, and reduces assembly errors.

[0025] The working principle of the entire device is as follows: In actual use, when traditional optical isolators are applied to environments with large day-night temperature differences, the excessively high temperature reduces the magnetic force of the module providing magnetic force in its Faraday rotator. This further weakens the effective magnetic field obtained by the internal rotating crystal, causing the optical rotation angle to deviate from the required 45-degree operating point of the device. In this device, when the corresponding cylindrical magnet 213 and Faraday rotator crystal 215 are subjected to temperature drift, the thermistor 217, located outside the Faraday rotator crystal 215 and in the same spatial position, monitors the temperature change in real time. Based on the estimated force data, it compares and calculates the force in real time through the sensed temperature difference. Thus, the power module 212 drives the magnetic compensation coil 216 to compensate for the lost magnetic force of the cylindrical magnet 213 in real time. To further verify the accuracy of the compensation and the overall actual angle deviation, the polarizer 206 and the analyzer 208 are fixed together by the connecting frame 218. A magnetic cylinder fixing half-ring 219 is installed on the side to fix the cylindrical magnet 213, thereby ensuring that the three are in a fixed position. At the same time, a baffle 222 is set on the inner side of the output end connecting ring 209. The channel on the inner side of the baffle 222 ensures that the light spot of the main light path can pass normally, while the outer part blocks the edge diverging light and makes the edge light reflect on the baffle 222. Since the signal light passes through the timing lens 205 at this time, the light is in a relatively parallel state. At this time, the slits 223 opened on both sides of the baffle 222 allow the light path to reach the surface of the refractor 225. The signal light is reflected to the top by the refractor 225 and amplified by the convex lens 228, so that the light signal directly contacts the photodiode module 229. The photodiode module 229 reflects the drift of the optical rotation angle in real time through the change of light intensity. At this time, the current is further controlled by the magnetic compensation coil 216 to realize the closed-loop adjustment of the magnetic field. This verifies and tests the first result, and then performs a second and overall adjustment based on the first correction.

[0026] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An online high-precision optical isolation device based on a Faraday rotator, characterized in that: It includes a mounting base (1) and a temperature compensation mechanism (2), wherein the temperature compensation mechanism (2) is disposed on the inner side of the mounting base (1); The temperature compensation mechanism (2) includes a magnetic compensation coil (216), a thermistor (217), a slit (223), a convex lens (228), and a photodiode module (229). The magnetic compensation coil (216) is located outside the thermistor (217), the slit (223) is located at the bottom of the convex lens (228), and the photodiode module (229) is located at the top of the convex lens (228). The thermistor (217) is used to detect temperature changes in real time. The magnetic compensation coil (216) adjusts the current in real time according to the temperature change difference detected by the thermistor (217) to provide adaptive auxiliary magnetic force. The slit (223) is used to sieve the light spot. The convex lens (228) is used to amplify the light spot signal. The photodiode module (229) is used to check the changes in the detected light spot and provide secondary real-time detection.

2. The online high-precision optical isolation device based on a Faraday rotator according to claim 1, characterized in that: The temperature compensation mechanism (2) also includes a housing (201), which is installed inside the mounting base (1). One end of the housing (201) is provided with an input end cylinder (202), the other side of the input end cylinder (202) is provided with an input end connecting ring (203), the other side of the input end connecting ring (203) is provided with an input end cap (204), and the inside of the input end connecting ring (203) is provided with a timing lens (205).

3. The online high-precision optical isolation device based on a Faraday rotator according to claim 2, characterized in that: A polarizer (206) is installed on the inner side of the input end cylinder (202), an output end cylinder (207) is installed on the other side of the outer shell (201), an output end connecting ring (209) is installed on the other side of the output end cylinder (207), an output end cap (211) is installed on the other side of the output end connecting ring (209), a focusing lens (210) is installed on the inner side of the output end connecting ring (209), and a polarizer (208) is installed on the inner side of the output end cylinder (207).

4. The online high-precision optical isolation device based on a Faraday rotator according to claim 3, characterized in that: A connecting frame (218) is installed on the inner side of the input end cylinder (202) and the detector (208). A magnetic cylinder fixing half ring (219) is installed on the outer side of the connecting frame (218). A cylindrical magnet (213) is installed on the inner side of the magnetic cylinder fixing half ring (219). A limiting collar (214) is installed on the inner side of the cylindrical magnet (213). The magnetic compensation coil (216) is sleeved on the outer side of the limiting collar (214). The magnetic compensation coil (216) is located on the outer side of the Faraday rotating crystal plate (215).

5. The online high-precision optical isolation device based on a Faraday rotator according to claim 4, characterized in that: The thermistor (217) is installed on the inner bottom of the limiting collar (214), and the output terminal of the thermistor (217) is electrically connected to the power module (212), which is installed on the bottom of the outer shell (201).

6. The online high-precision optical isolation device based on a Faraday rotator according to claim 5, characterized in that: The output end of the magnetic compensation coil (216) passes through the limiting collar (214) and is electrically connected to the power module (212). A fixing ring (220) is installed on the outside of the connecting frame (218). An optical path slot (221) is opened on the top of the fixing ring (220). A baffle (222) is installed on the inside of the fixing ring (220). There are two slits (223), and the two slits (223) are respectively opened on both sides of the baffle (222).

7. The online high-precision optical isolation device based on a Faraday rotator according to claim 6, characterized in that: A lens holder (224) is installed on the inner side of the fixing ring (220), and two refractors (225) are installed on the inner side of the lens holder (224).

8. The online high-precision optical isolation device based on a Faraday rotator according to claim 7, characterized in that: The two refractors (225) correspond to the two slits (223) respectively, and the optical path slot (221) is located on top of the two refractors (225).

9. The online high-precision optical isolation device based on a Faraday rotator according to claim 8, characterized in that: The top of the outer casing (201) is provided with a slot (226), and a convex lens frame (227) is provided inside the slot (226). There are two convex lenses (228), and the two convex lenses (228) are installed inside the convex lens frame (227).

10. The online high-precision optical isolation device based on a Faraday rotator according to claim 9, characterized in that: The slot (226) is located at the top of the optical path slot (221) and corresponds to the optical path slot (221). The photodiode module (229) is installed on the top of the housing (201). The photodiode module (229) is located at the top of the slot (226).

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