Three-port bipolar isolation optical circulator

Abstract

The utility model relates to a three-port bipolar isolation optical circulator. The three-port bipolar isolation optical circulator comprises a first collimator 101, a first circulator core, a hexagonal prism 103, a second circulator core and a second collimator. According to the utility model, a unique optical path design is adopted, and a compact and small two-stage isolation optical circulator structure is realized by reasonably combining the light emitting intersection angle of the double-fiber collimator and the special optical path design in the optical circulator, so that the bandwidth isolation degree of the optical circulator is effectively improved, and the size and the cost of the optical circulator can be remarkably reduced; and powerful support is provided for further development of an optical fiber communication system.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber communication technology, specifically to a three-port bipolar isolated optical circulator. Background Technology

[0002] Optical circulators are important optical communication devices widely used in fiber optic communication, fiber optic sensing, and fiber lasers. They are multi-port, non-reciprocal devices capable of unidirectional transmission of optical signals, typically used to transfer input optical signals from one port to the next in sequence without returning or being transmitted to other ports. In fiber optic communication systems, optical circulators are often used in conjunction with other devices such as fiber Bragg gratings and optical switches to achieve feature-rich optical signal processing and transmission. Traditional optical circulators mostly employ magneto-optical materials, such as yttrium-doped iron garnet (YIG), to achieve unidirectional optical signal transmission through the Faraday effect. However, with the development of optical communication technology, the performance requirements of fiber optic systems are constantly increasing, such as low insertion loss, high isolation, wide bandwidth, miniaturization, and low cost. Traditional optical circulators are gradually becoming unable to meet these increasingly stringent requirements.

[0003] In recent years, to further reduce system costs, researchers have proposed the concept of a two-stage isolated optical circulator. This two-stage isolated circulator can effectively prevent interference from reflected light to the signal source within a wide wavelength range, ensuring signal integrity and transmission efficiency, and is suitable for high-speed, long-distance, and high-capacity fiber optic communication network systems. However, the isolation level of existing two-stage isolated optical circulators cannot meet the usage requirements, which to some extent limits their application scope. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a three-port bipolar isolated optical circulator.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A three-port bipolar isolated optical circulator includes a first collimator, a first circulator core, a hexagonal prism, a second circulator core, and a second collimator;

[0007] The first collimator is a dual-fiber collimator. The two fibers of the first collimator are Port1 and Port3, respectively. The first collimator is used to collimate the output light from Port1 into parallel light.

[0008] The second collimator is a single-fiber collimator. The fiber of the second collimator is Port2. The second collimator is used to collimate the output light of Port2 into parallel light.

[0009] The collimated parallel beams of Port1 and Port3 of the first collimator are symmetrical about the horizontal direction and form an angle 2A between them. The collimated parallel beam of Port1 points downward horizontally at the angle A, and the collimated parallel beam of Port3 points upward horizontally at the angle A.

[0010] The hexagonal prism is used to shift the light emitted obliquely from Port1 through the first circulator core upward and correct it to be horizontally incident on the second circulator core. At the same time, it is used to shift and correct the light emitted horizontally from Port2 through the second circulator core upward to be obliquely incident on the first circulator core at an angle A upward.

[0011] The light emitted from the first circulator core is coupled to the Port3 port for reception;

[0012] The light emitted from the second circulator core is coupled to the Port2 port for reception.

[0013] Furthermore, the upper left and lower right sides of the hexagonal prism form an angle B, so that the light emitted obliquely from Port1 through the first circulator core is corrected to be horizontal after passing through the hexagonal prism. The lower left and upper right sides of the hexagonal prism form an angle C, so that the light emitted horizontally from Port2 through the second circulator core is corrected to be horizontally upward and obliquely incident on the first circulator core at an angle A after passing through the hexagonal prism.

[0014] Furthermore, the first circulator core includes a first polarizing beam splitter prism, a first half-wave plate, a first Faraday rotator crystal, and a second polarizing beam splitter prism. The first polarizing beam splitter prism has a trapezoidal cross-section and contains a first polarizing beam splitting film. The second polarizing beam splitter prism has a parallelogram cross-section and contains a second polarizing beam splitting film. The first and second polarizing beam splitters are used to input or output signal light, and the first and second polarizing beam splitters are used to separate or combine P-polarized light and S-polarized light in the signal light. The first half-wave plate and the first Faraday rotator crystal constitute a first optical rotation combination, used to perform a 90° polarization rotation on the signal light in a single transmission direction, while not performing polarization rotation on the signal light in the other transmission direction.

[0015] The second circulator core includes a third polarizing beam splitter prism, a second half-wave plate, a second Faraday rotator crystal, and a fourth polarizing beam splitter prism. The cross-section of the third polarizing beam splitter prism is a parallelogram structure with a base angle, and a third polarizing beam splitting film is disposed inside it. The cross-section of the fourth polarizing beam splitter prism is a trapezoidal structure, and a fourth polarizing beam splitting film is disposed inside it. The third and fourth polarizing beam splitters are used for inputting or outputting signal light, and the third and fourth polarizing beam splitting films are used for separating or combining P-polarized light and S-polarized light in the signal light. The second half-wave plate and the second Faraday rotator crystal constitute a second optical rotation combination, which is used to rotate the polarization of signal light in a single transmission direction by 90°, while not rotating the polarization of signal light in the other transmission direction.

[0016] The light from Port1 is collimated by the first collimator and then input horizontally downwards into the first polarizing beam splitter, where it is transmitted to the first polarizing beam splitter film. The P-component of the signal light is transmitted through the first polarizing beam splitter film, then passes through the optical rotation combination composed of the first half-wave plate and the first Faraday rotator crystal, maintaining its polarization direction. The P-light then enters the second polarizing beam splitter, is reflected by its upper surface, and is transmitted through the second polarizing beam splitter film. It is then transmitted to the lower surface of the second polarizing beam splitter and reflected, before being output from the right side of the second polarizing beam splitter. The S-component of the signal light is reflected by the first polarizing beam splitter film, then by its lower surface, and then passes through the optical rotation combination composed of the first half-wave plate and the first Faraday rotator crystal, maintaining its polarization direction. The S-light then enters the second polarizing beam splitter film, is reflected by its lower surface, and is output from the right side of the second polarizing beam splitter. Finally, the P-light and S-light components are combined and output from the lower right side of the second polarizing beam splitter.

[0017] The combined light is input into the lower left end face of the hexagonal prism and then translated upwards for transmission. It is then output from the upper right end face of the hexagonal prism. The output light is aligned to a horizontal direction and then transmitted to the third polarizing beam splitter to the right, where it is transmitted to the third polarizing beam splitter film. The P-component of the signal light is transmitted through the third polarizing beam splitter, then rotated 90° after passing through the optical rotation combination consisting of the second half-wave plate and the second Faraday rotator crystal, turning the P-light into the S-light. The S-light enters the fourth polarizing beam splitter, is reflected by the lower end face of the fourth polarizing beam splitter, and then reflected again by the fourth polarizing beam splitter. It is then output from the right side of the fourth polarizing beam splitter. The S-component of the signal light is reflected by the third polarizing beam splitter, then reflected by the upper end face of the third polarizing beam splitter, then rotated 90° after passing through the optical rotation combination consisting of the second half-wave plate and the second Faraday rotator crystal, turning the S-light into the P-light. The P-light enters the fourth polarizing beam splitter, is transmitted through the fourth polarizing beam splitter, and then output from the right side of the fourth polarizing beam splitter. The P-light and S-light components are then combined at the right end face of the fourth polarizing beam splitter and output. The combined light is transmitted to the right to the second collimator and finally reaches Port2.

[0018] Similarly, the light output from Port2 passes through the second collimator and is incident on the second circulator core. The polarization direction of the P-beam and S-beam remains unchanged after passing through the second optical rotation combination, and then it is output from the lower left end face of the third polarizing beam splitter. After passing through the hexagonal prism, it is corrected into horizontally downward light and input to the upper right end face of the second polarizing beam splitter of the first circulator core. The polarization direction of the P-beam and S-beam is rotated by 90° after passing through the first optical rotation combination, and then it is output horizontally downward from the left end face of the first polarizing beam splitter.

[0019] Furthermore, this utility model also includes a circulator core base, a glass outer sealing tube, and a magnetic ring;

[0020] The circulator core base is used to bond and fix the first circulator core, the second circulator core, and the hexagonal prism;

[0021] The outer glass sealing tube is used to bond and fix the circulator core base, the first collimator, and the second collimator.

[0022] The magnetic ring is fitted onto the outside of the glass outer sealing tube and is used to provide a magnetic field.

[0023] The present invention adopts the above technical solution and has the following beneficial effects:

[0024] This utility model optical circulator adopts a unique optical path design. By reasonably combining the output crossover angle of the dual fiber collimators with the special optical path design inside the optical circulator, a compact and small two-stage isolated optical circulator structure is realized. At the same time, it effectively improves the bandwidth isolation of the optical circulator and significantly reduces its size and cost, providing strong support for the further development of optical fiber communication systems. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0027] Figure 2 This is a schematic diagram showing the angle between the collimated parallel light from Port1 and Port3 of the first collimator.

[0028] Figure 3 This is a structural diagram of the first circulator core;

[0029] Figure 4 This is a structural diagram of the second circulator core;

[0030] Figure 5 A schematic diagram of the intersection of a hexagonal prism;

[0031] Figure 6 This is a schematic diagram of the optical path from Port1 to Port2;

[0032] Figure 7 This is a schematic diagram of the optical path from Port2 to Port3. Detailed Implementation

[0033] like Figures 1-7 As shown, this utility model discloses a three-port bipolar isolated optical circulator, which includes a first collimator 101, a first circulator core 102, a hexagonal prism 103, a second circulator core 104, a second collimator 105, a circulator core base 107, a glass outer sealing tube 106, and a magnetic ring 108.

[0034] The circulator core base 107 is used to bond and fix the first circulator core 102, the second circulator core 104 and the hexagonal prism 103.

[0035] The outer glass sealing tube 106 is used to bond and fix the circulator core base 107, the first collimator 101, and the second collimator 105.

[0036] A magnetic ring 108 is fitted onto the outside of a glass outer tube 106. The magnetic ring 108 is used to provide a magnetic field, enabling the Faraday rotator crystal to rotate the polarization direction of the input light under the magnetic field.

[0037] The first collimator 101 is a dual-fiber collimator. The two fibers of the first collimator 101 are Port1 port and Port3 port, respectively. The first collimator 101 is used to collimate the output light of Port1 port into parallel light.

[0038] The second collimator 105 is a single-fiber collimator. The fiber of the second collimator 105 is the Port2 port. The second collimator 105 is used to collimate the output light of the Port2 port into parallel light.

[0039] The collimated parallel beams of Port1 and Port3 of the first collimator 101 are symmetrical about the horizontal direction and form an angle 2A between them. The collimated parallel beam of Port1 points downward horizontally at the angle A, and the collimated parallel beam of Port3 points upward horizontally at the angle A.

[0040] The hexagonal prism 103 is used to shift the light emitted obliquely from Port1 through the first circulator core 102 upward and correct it to be horizontally incident on the second circulator core 104. At the same time, it is used to shift and correct the light emitted horizontally from Port2 through the second circulator core 104 upward to be obliquely incident on the first circulator core 102 at an angle A upward.

[0041] The light emitted from the first circulator core 102 is coupled to the Port3 port for reception;

[0042] The light emitted from the second circulator core 104 is coupled to the Port2 port for reception.

[0043] The hexagonal prism 103 is made of N-SF11. Angle B is formed between the upper left and lower right sides of the hexagonal prism 103, causing light emitted obliquely from the first circulator core 102 at Port1 to be corrected to a horizontal position after passing through the hexagonal prism 103. Angle C is formed between the lower left and upper right sides of the hexagonal prism 103, causing light emitted horizontally from the second circulator core 104 at Port2 to be corrected to an upward horizontal angle A before obliquely entering the first circulator core 102. Angles B and C are both 1.8°, angle A is 2.24°, and 2A is 4.48°.

[0044] The first circulator core 102 includes a first polarizing beam splitter 1021, a first half-wave plate 1022, a first Faraday rotator crystal 1023, and a second polarizing beam splitter 1024. The first polarizing beam splitter 1021 has a trapezoidal cross-section and a first polarizing beam splitting film inside. The second polarizing beam splitter 1024 has a parallelogram cross-section and a second polarizing beam splitting film inside. The first polarizing beam splitter 1021 and the second polarizing beam splitter 1024 are used to input or output signal light. The first polarizing beam splitter film and the second polarizing beam splitter film are used to separate or synthesize P-polarized light and S-polarized light in the signal light. The first half-wave plate 1022 and the first Faraday rotator crystal 1023 constitute a first optical rotation combination, which is used to perform a 90° polarization rotation on the signal light in a single transmission direction, while not performing a polarization rotation on the signal light in the other transmission direction.

[0045] The second circulator core 104 includes a third polarizing beam splitter 1041, a second half-wave plate 1043, a second Faraday rotator crystal 1042, and a fourth polarizing beam splitter 1044. The cross-section of the third polarizing beam splitter 1041 is a parallelogram structure with a base angle, and a third polarizing beam splitting film is disposed inside it. The cross-section of the fourth polarizing beam splitter 1044 is a trapezoidal structure, and a fourth polarizing beam splitting film is disposed inside it. The third polarizing beam splitter 1041 and the fourth polarizing beam splitter 1044 are used for inputting or outputting signal light, and the third polarizing beam splitting film and the fourth polarizing beam splitting film are used for separating or combining P-polarized light and S-polarized light in the signal light. The second half-wave plate 1043 and the second Faraday rotator crystal 1042 constitute a second optical rotation combination, which is used to perform a 90° polarization rotation on the signal light in a single transmission direction, while not performing a polarization rotation on the signal light in the other transmission direction.

[0046] The light from Port1 is collimated by the first collimator 101 and then input horizontally downwards into the first polarizing beam splitter 1021, where it is transmitted to the first polarizing beam splitter film. The P-component of the signal light is transmitted through the first polarizing beam splitter film, then passes through the optical rotation combination composed of the first half-wave plate 1022 and the first Faraday rotator crystal 1023, maintaining its polarization direction. The P-component then enters the second polarizing beam splitter 1024, is reflected by its upper surface, and is transmitted through the second polarizing beam splitter film. It is then reflected by the lower surface of the second polarizing beam splitter 1024 and output from the right side of the second polarizing beam splitter 1024. The S-component of the signal light, after passing through the first polarizing beam splitter film... The light is reflected, then reflected by the lower end face of the first polarizing beam splitter 1021, and then passes through the optical rotation combination composed of the first half-wave plate 1022 and the first Faraday rotator crystal 1023. The polarization direction remains unchanged. The S-light then enters the second polarizing beam splitter 1024 and is reflected by the second polarizing beam splitter film. It is then transmitted to the lower end face of the second polarizing beam splitter 1024 for reflection and output from the right side of the second polarizing beam splitter 1024. Then the P-light and S-light components are combined and output from the lower end face of the right side of the second polarizing beam splitter 1024.

[0047] The combined light is input to the lower left end face of hexagonal prism 103 and then transmitted upwards. It is then output from the upper right end face of hexagonal prism 103, where it is aligned horizontally and transmitted to the right to the third polarizing beam splitter 1041, and finally to the third polarizing beam splitter film. The P-component of the signal light is transmitted through the third polarizing beam splitter film, then rotated 90° after passing through the optical rotation combination of the second half-wave plate 1042 and the second Faraday rotator crystal 1043, transforming the P-light into the S-light. The S-light enters the fourth polarizing beam splitter 1044, is reflected by its lower end face, and then reflected again by the fourth polarizing beam splitter film; it is then output from the right side of the fourth polarizing beam splitter 1044. The S-component of the signal light is reflected by the third polarizing beam splitter film and then... The light is reflected from the upper surface of mirror 1041, and then its polarization direction is rotated by 90° after passing through the optical rotation combination composed of the second half-wave plate 1042 and the second Faraday optical rotation crystal 1043. The S-light becomes the P-light, which enters the fourth polarization beam splitter 1044 and is then transmitted by the fourth polarization beam splitter film. It is then output from the right side of the fourth polarization beam splitter 1044. The P-light and S-light components are then combined and output from the right end face of the fourth polarization beam splitter 1024. The combined light is transmitted to the right to the second collimator and finally reaches Port2.

[0048] Similarly, the light output from Port2 passes through the second collimator 105 and is incident on the second circulator core 104. The polarization direction of the P-light and S-light remains unchanged after the second optical rotation combination, and then it is output from the lower left end face of the third polarizing beam splitter 1041. After passing through the hexagonal prism 103, it is corrected into horizontally downward light and input to the upper right end face of the second polarizing beam splitter 1024 of the first circulator core. The polarization direction of the P-light and S-light is rotated by 90° after the first optical rotation combination, and then it is output horizontally downward from the left end face of the first polarizing beam splitter 1021.

[0049] The specific embodiments of this utility model have been described above. However, those skilled in the art should understand that this is only an example. Those skilled in the art can make various changes or modifications to this embodiment without departing from the principle and essence of this utility model, but all such changes and modifications fall within the protection scope of this utility model.

Claims

1. A three-port bipolar isolated optical circulator, characterized in that: It includes a first collimator, a first circulator core, a hexagonal prism, a second circulator core, and a second collimator; The first collimator is a dual-fiber collimator. The two fibers of the first collimator are Port1 and Port3, respectively. The first collimator is used to collimate the output light from Port1 into parallel light. The second collimator is a single-fiber collimator. The fiber of the second collimator is Port2. The second collimator is used to collimate the output light of Port2 into parallel light. The collimated parallel beams of Port1 and Port3 of the first collimator are symmetrical about the horizontal direction and form an angle 2A between them. The collimated parallel beam of Port1 points downward horizontally at the angle A, and the collimated parallel beam of Port3 points upward horizontally at the angle A. The hexagonal prism is used to shift the light emitted obliquely from Port1 through the first circulator core upward and correct it to be horizontally incident on the second circulator core. At the same time, it is used to shift and correct the light emitted horizontally from Port2 through the second circulator core upward to be obliquely incident on the first circulator core at an angle A upward. The light emitted from the first circulator core is coupled to the Port3 port for reception; The light emitted from the second circulator core is coupled to the Port2 port for reception.

2. A three-port bipolar isolated optical circulator according to claim 1, characterized in that: The hexagonal prism forms an angle B between its upper left and lower right sides, causing the light emitted obliquely from Port1 through the first circulator core to be corrected to be horizontal after passing through the hexagonal prism. The hexagonal prism forms an angle C between its lower left and upper right sides, causing the light emitted horizontally from Port2 through the second circulator core to be corrected to be horizontally upward and obliquely incident on the first circulator core at an angle A after passing through the hexagonal prism.

3. A three-port bipolar isolated optical circulator according to claim 1, characterized in that: The first circulator core includes a first polarizing beam splitter prism, a first half-wave plate, a first Faraday rotator crystal, and a second polarizing beam splitter prism. The first polarizing beam splitter prism has a trapezoidal cross-section and contains a first polarizing beam splitting film. The second polarizing beam splitter prism has a parallelogram cross-section and contains a second polarizing beam splitting film. The first and second polarizing beam splitters are used to input or output signal light, and the first and second polarizing beam splitters are used to separate or combine P-polarized and S-polarized light in the signal light. The first half-wave plate and the first Faraday rotator crystal constitute a first optical rotation combination, used to perform a 90° polarization rotation on the signal light in a single transmission direction, while not performing polarization rotation on the signal light in the other transmission direction. The second circulator core includes a third polarizing beam splitter prism, a second half-wave plate, a second Faraday rotator crystal, and a fourth polarizing beam splitter prism. The cross-section of the third polarizing beam splitter prism is a parallelogram structure with a base angle, and a third polarizing beam splitting film is disposed inside it. The cross-section of the fourth polarizing beam splitter prism is a trapezoidal structure, and a fourth polarizing beam splitting film is disposed inside it. The third and fourth polarizing beam splitters are used for inputting or outputting signal light, and the third and fourth polarizing beam splitting films are used for separating or combining P-polarized light and S-polarized light in the signal light. The second half-wave plate and the second Faraday rotator crystal constitute a second optical rotation combination, which is used to rotate the polarization of signal light in a single transmission direction by 90°, while not rotating the polarization of signal light in the other transmission direction.

4. A three-port bipolar isolated optical circulator according to claim 3, characterized in that: It also includes a circulator core base, a glass outer sealing tube, and a magnetic ring; The circulator core base is used to bond and fix the first circulator core, the second circulator core, and the hexagonal prism; The outer glass sealing tube is used to bond and fix the circulator core base, the first collimator, and the second collimator. The magnetic ring is fitted onto the outside of the glass outer sealing tube and is used to provide a magnetic field.

Images