Four-port optical circulator core
By designing a four-port optical circulator core, the combination of polarization spectroscopic prism, Faraday optical rotary crystal and polarizer is used to achieve multi-stage isolation, which solves the problem of insufficient isolation of the existing optical circulator core and improves the optical communication module Performance and reduce costs.
Patent Information
- Application Number
- CN202421333014.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-12
- Publication Date
- 2025-02-11
- Estimated Expiration
- 2034-06-12
AI Technical Summary
When the existing optical circulator core is input and output in multiple ports, the isolation is insufficient, making it difficult to meet the higher requirements of advanced optical communication modules for isolation, insertion loss and return loss.
A four-port light circulator core is designed to achieve multi-stage isolation by combining the first polarization spectroscopic prism, the second polarization spectroscopic prism, the Faraday optical rotation crystal, the half-wave plate, the P ray polarizer and the third polarization spectroscopic prism, and the multi-stage isolation is achieved. Through the amplicon film and specific optical path design, the analysis ability of signal light is improved.
Achieved multi-stage isolation of four channels, ensuring return loss of each channel >70dB, reducing crosstalk between signal ports, and improving the spectroscopy capability of the incident signal light on the common port, improving the performance of the optical communication module and reducing cost.
Smart Images
Figure CN222461832U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optical fiber communication, and in particular to a four-port optical circulator core which can be flexibly integrated into various functional devices or modules (such as optical transceiver modules, optical information sensors). Background Art
[0002] The optical circulator is based on the Faraday magneto-optical effect. When light passes through a material with a non-zero magneto-optical tensor, its polarization state will be affected by an external magnetic field and change, thus achieving directional propagation of multi-port input and output. Its function is to make the optical signal only be transmitted along the specified port sequence. When the optical signal is input from the specified port, it can only be output along the specified port in the device. When the transmission order of the optical signal is changed, that is, when it is not transmitted according to the specified port, its loss is very large, which can achieve the isolation of the input signal.
[0003] In the currently widely used optical circulator core structure, the signal light returned from the common port is usually transmitted to a single receiving port, which limits the ability to analyze the signal light information of different polarization states in the receiving port. Since the currently widely used optical circulator core realizes polarization splitting through a polarization splitter film, and the isolation between different ports is affected by the extinction ratio of the polarization splitter film, the theoretical isolation of existing optical circulator cores on the market is usually around 20dB, and the isolation between different ports is either achieved through a single optical circulator core to achieve single-stage isolation (~20dB) or through a circulator core array to achieve multi-stage isolation (>20dB), and additional optical isolators are usually added to the circulator structure to achieve the purpose of multi-stage isolation, which limits the cost and assembly space of the optical module and limits the choice of optical performance. Summary of the invention
[0004] The utility model aims to overcome the shortcomings of the prior art and provide a four-port optical circulator core.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] A four-port optical circulator core comprises a first polarization beam splitter prism, a second polarization beam splitter prism, a Faraday rotator crystal, a half-wave plate, a P-ray polarizer and a third polarization beam splitter prism arranged in sequence;
[0007] The Faraday rotator crystal and the half-wave plate are combined into an optical rotation mechanism, 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 another transmission direction;
[0008] The cross section of the first polarization beam splitter prism is a square structure, the cross section of the second polarization beam splitter prism is a right-angled trapezoidal structure with a bottom angle of 45°, and the cross section of the third polarization beam splitter prism is a rectangular structure;
[0009] The end face where the right side of the cross section of the first polarization beam splitter prism is located is bonded to the end face where the long bottom side of the second polarization beam splitter prism is located and is close to the position where the bottom angle is 90°. The first polarization beam splitter prism is provided with a first polarization beam splitter film that divides the end face bonded to the second polarization beam splitter prism into an upper and lower part, and the first polarization beam splitter film forms an angle of 45° with the upper and lower end faces of the first polarization beam splitter prism; the end face of the second polarization beam splitter prism that is not bonded to the first polarization beam splitter prism is bonded to an end face of the Faraday rotator crystal, and the second polarization beam splitter prism is provided with a second polarization beam splitter film that divides the end face bonded to the first polarization beam splitter prism into an upper and lower part, and the second polarization beam splitter film forms an angle of 45° with the upper end face of the second polarization beam splitter prism and the second polarization beam splitter film. The lower end faces of the prisms are parallel, and the lower end face of the second polarization beam splitter prism is provided with a high reflection film; the end face of the Faraday rotator crystal that is not bonded to the second polarization beam splitter prism is bonded to one end face of the half-wave plate, the other end face of the half-wave plate is bonded to one end face of the P-ray polarizer, and the other end face of the P-ray polarizer is bonded to one end face of the third polarization beam splitter prism; the third polarization beam splitter prism is provided with a third polarization beam splitter film and a fourth polarization beam splitter film that divide the end face bonded to the P-ray polarizer into three parts: upper, middle and lower parts, and the third polarization beam splitter film is at an angle of 45° to the upper end face of the third polarization beam splitter prism, the fourth polarization beam splitter film is parallel to the third polarization beam splitter film, and the lower end face of the third polarization beam splitter prism is at an angle of 45° to the fourth polarization beam splitter film;
[0010] The signal port Port1 is located on the left end face of the first polarization beam splitter prism; the signal port Port2 is located on the other end face of the third polarization beam splitter prism that is not bonded to the linear polarizer, and is at the same horizontal position as the signal port Port1; the signal port Port3 is located on the end face where the long bottom side of the second polarization beam splitter prism is located, and is not bonded to the first polarization beam splitter prism; the signal port Port4 is located on the end face of the third polarization beam splitter prism that is bonded to the linear polarizer, and is not bonded to the linear polarizer.
[0011] Furthermore, the P-ray polarizer is bonded together with the half-wave plate and the Faraday rotator crystal.
[0012] Furthermore, the positions of the half-wave plate and the Faraday rotator crystal can be interchanged.
[0013] Furthermore, all the bonding surfaces and signal port surfaces are provided with anti-reflection films.
[0014] Furthermore, the angle at which the signal light enters the circulator core is 1 to 5 degrees.
[0015] The utility model adopts the above technical scheme, and can realize four-channel multi-level isolation, meet the optical communication module (transceiver) higher requirements for isolation, insertion loss and return loss, ensure that the return loss of each channel is greater than 70dB, and the input and output lights of the four ports remain parallel, which is convenient for the coupler to adjust the coupling, and plays a multi-level isolation role for the signal light returned from the common port, so that the isolation degree for the transmitting port is greater than 40dB, which greatly reduces the crosstalk between the signal ports, and splits the signal light incident on the common port, improves the analysis ability of the signal light, and is of great help to improve the performance of the optical communication module and reduce the cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific implementations:
[0017] Figure 1 A schematic diagram of a brief implementation structure of the utility model;
[0018] Figure 2 It is a schematic diagram of light propagation from Port1 to Port2;
[0019] Figure 3 It is a schematic diagram of light propagation from Port2 to Port3 and Port4;
[0020] In all the drawings, the same reference numerals represent the same technical features, specifically: a short bidirectional arrow represents the P light polarization state, and a dot represents the S light polarization state. DETAILED DESCRIPTION
[0021] Please refer to Figure 1The present embodiment provides a four-port optical circulator core, which includes a first polarization beam splitter prism 101, a second polarization beam splitter prism 102, a Faraday rotator crystal 103, a half-wave plate 104, a P-ray polarizer 105, and a third polarization beam splitter prism 106 arranged in sequence. The Faraday rotator crystal 103 and the half-wave plate 104 are combined into a rotation mechanism, which is used to rotate the polarization of the signal light in a single transmission direction by 90°, but not to rotate the polarization of the signal light in another transmission direction (the polarization direction does not rotate when the light propagates from left to right, and the polarization direction rotates by 90° when the light propagates from right to left). The positions of the half-wave plate 104 and the Faraday rotator crystal 103 can be interchanged. The P-ray polarizer is bonded to the half-wave plate 104 and the Faraday rotator crystal 103. The cross section of the first polarization beam splitter prism 101 is a square structure, the cross section of the second polarization beam splitter prism 102 is a right-angled trapezoidal structure with a bottom angle of 45°, and the cross section of the third polarization beam splitter prism 106 is a rectangular structure. The end face where the right side of the cross section of the first polarization beam splitter prism 101 is located is bonded to the end face where the long bottom side of the second polarization beam splitter prism is located and close to the position where the bottom angle is 90°. The first polarization beam splitter prism 101 is provided with a first polarization beam splitter film 1011 that divides the end face bonded to the second polarization beam splitter prism 102 into upper and lower parts, and the first polarization beam splitter film 1011 forms an angle of 45° with the upper and lower end faces of the first polarization beam splitter prism 101. The end face of the second polarization beam splitter prism 102 not bonded to the first polarization beam splitter prism 101 is bonded to one end face of the Faraday rotator crystal 103. The second polarization beam splitter prism 102 is provided with a second polarization beam splitter film 1012 which divides the end face bonded to the first polarization beam splitter prism 101 into two parts, the upper and lower parts. The second polarization beam splitter film 1012 forms an angle of 45° with the upper end face of the second polarization beam splitter prism 102 and is parallel to the lower end face of the second polarization beam splitter prism 102. A high reflection film is provided on the lower end face of the second polarization beam splitter prism 102. The end face of the Faraday rotator crystal 103 not bonded to the second polarization beam splitter prism 102 is bonded to one end face of the half-wave plate 104. The other end face of the half-wave plate 104 is bonded to one end face of the P-ray polarizer 105. The other end face of the P-ray polarizer 105 is bonded to one end face of the third polarization beam splitter prism 106. The third polarization splitter prism 106 is provided with a third polarization splitter film 1013 and a fourth polarization splitter film 1014 which divide the end face of the third polarization splitter prism 106 which is bonded to the P-ray polarizer into three parts: upper, middle and lower parts. The third polarization splitter film 1013 is at an angle of 45° to the upper end face of the third polarization splitter prism 106, the fourth polarization splitter film 1014 is parallel to the third polarization splitter film 1013, and the lower end face of the third polarization splitter prism 106 is at an angle of 45° to the fourth polarization splitter film 1014.The signal port Port1 is located on the left end face of the first polarization beam splitter prism, the signal port Port2 is located on the other end face of the third polarization beam splitter prism that is not bonded to the linear polarizer, and is at the same horizontal position as the signal port Port1, the signal port Port3 is located on the end face where the long bottom side of the second polarization beam splitter prism is located, and is not bonded to the first polarization beam splitter prism, and the signal port Port4 is located on the end face of the third polarization beam splitter prism that is bonded to the linear polarizer, and is not bonded to the linear polarizer.
[0022] In the utility model, anti-reflection films are arranged on all the bonding surfaces and signal port surfaces. The angle at which the signal light enters the circulator core is 1-5 degrees.
[0023] like Figure 2 As shown, the P polarized light is incident on the first polarization beam splitter prism 101 from the signal port Port1, and is transmitted after passing through the first polarization beam splitter film 1011, and is incident on the second polarization beam splitter prism 102, and is transmitted after passing through the second polarization beam splitter film 1012. After the P polarized light passes through the Faraday rotator crystal 103 and the half-wave plate 104 respectively, the polarization state does not change, and then the P polarized light is incident on the P light polarizer 105, and is transmitted, and is incident on the third polarization beam splitter prism 106, and is output from the upper half of the right end surface of the third polarization beam splitter prism to the signal port Port2 after passing through the third polarization beam splitter film 1013.
[0024] like Figure 3 As shown, the signal light enters the third polarization beam splitter prism 106 from the signal port Port2, and the P polarized light in the signal light is transmitted and the S polarized light is reflected through the third polarization beam splitter film 1011. After the P polarized light passes through the P light polarizer 105, the P polarized light passes through the half-wave plate 104 and the Faraday rotator crystal 103 respectively, and the original P polarized light becomes S polarized light. The rotated S polarized light enters the second polarization beam splitter prism 102, is reflected by the second polarization beam splitter film 1012, and is reflected by the lower end surface of the second polarization beam splitter prism 102 and output to the signal port Port3; the S polarized light in the signal light is reflected by the third polarization beam splitter film 1013 and then reflected by the fourth polarization beam splitter film, and output to the signal port Port4.
[0025] The above describes the specific implementation of the present invention, but 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 implementation without departing from the principle and essence of the present invention, but these changes and modifications are all within the scope of protection of the present invention.
Claims
1. A four-port optical circulator core, characterized in that: It includes a first polarization beam splitter prism, a second polarization beam splitter prism, a Faraday rotator crystal, a half-wave plate, a P-ray polarizer and a third polarization beam splitter prism which are arranged in sequence; The Faraday rotator crystal and the half-wave plate are combined into an optical rotation mechanism, 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 another transmission direction; The cross section of the first polarization beam splitter prism is a square structure, the cross section of the second polarization beam splitter prism is a right-angled trapezoidal structure with a bottom angle of 45°, and the cross section of the third polarization beam splitter prism is a rectangular structure; The end face where the right side of the cross section of the first polarization beam splitter prism is located is bonded to the end face where the long bottom side of the second polarization beam splitter prism is located and is close to the position where the bottom angle is 90°. The first polarization beam splitter prism is provided with a first polarization beam splitter film that divides the end face bonded to the second polarization beam splitter prism into an upper and lower part, and the first polarization beam splitter film forms an angle of 45° with the upper and lower end faces of the first polarization beam splitter prism; the end face of the second polarization beam splitter prism that is not bonded to the first polarization beam splitter prism is bonded to an end face of the Faraday rotator crystal, and the second polarization beam splitter prism is provided with a second polarization beam splitter film that divides the end face bonded to the first polarization beam splitter prism into an upper and lower part, and the second polarization beam splitter film forms an angle of 45° with the upper end face of the second polarization beam splitter prism and the second polarization beam splitter film. The lower end faces of the prisms are parallel, and the lower end face of the second polarization beam splitter prism is provided with a high reflection film; the end face of the Faraday rotator crystal that is not bonded to the second polarization beam splitter prism is bonded to one end face of the half-wave plate, the other end face of the half-wave plate is bonded to one end face of the P-ray polarizer, and the other end face of the P-ray polarizer is bonded to one end face of the third polarization beam splitter prism; the third polarization beam splitter prism is provided with a third polarization beam splitter film and a fourth polarization beam splitter film that divide the end face bonded to the P-ray polarizer into three parts: upper, middle and lower parts, and the third polarization beam splitter film is at an angle of 45° to the upper end face of the third polarization beam splitter prism, the fourth polarization beam splitter film is parallel to the third polarization beam splitter film, and the lower end face of the third polarization beam splitter prism is at an angle of 45° to the fourth polarization beam splitter film; The signal port Port1 is located on the left end face of the first polarization beam splitter prism; the signal port Port2 is located on the other end face of the third polarization beam splitter prism that is not bonded to the linear polarizer, and is at the same horizontal position as the signal port Port1; the signal port Port3 is located on the end face where the long bottom side of the second polarization beam splitter prism is located, and is not bonded to the first polarization beam splitter prism; the signal port Port4 is located on the end face of the third polarization beam splitter prism that is bonded to the linear polarizer, and is not bonded to the linear polarizer.
2. A four-port optical circulator core according to claim 1, characterized in that: The P-ray polarizer is bonded together with the half-wave plate and the Faraday rotator crystal.
3. The four-port optical circulator core according to claim 1, characterized in that: The positions of the half-wave plate and the Faraday rotator crystal can be interchanged.
4. The four-port optical circulator core according to claim 1, characterized in that: All mating surfaces and signal port faces are anti-reflection coated.
5. The four-port optical circulator core according to claim 1, characterized in that: The angle at which the signal light enters the circulator core is 1~5°.