Unilateral fiber outlet device with isolation, wave combination and signal amplification functions

Abstract

The utility model discloses a unilateral fiber outlet device with isolation, wave combination and signal amplification functions. The unilateral fiber outlet device comprises an optical fiber head, a light splitting / combining device, a lambda1 optical rotation device, a lambda2 optical rotation device, a lens, a Faraday optical rotation device and a wedge angle reflector which are sequentially arranged, the optical fiber head is tightly formed by a lambda1 input optical fiber, a lambda2 input optical fiber and an output optical fiber; the input optical fiber and the output optical fiber are positioned on the same side of the device and are much smaller than a bilateral integrated device; the light splitting / combining device, the lambda1 optical rotation device, the lambda2 optical rotation device and the Faraday optical rotation device enable the device to integrate isolation and wave combination functions and have excellent insertion loss, polarization dependent loss and isolation index performance; the erbium-doped optical fiber serves as an output optical fiber, and when the light beam lambda1 and the light beam lambda2 which are input at the same time are the pumping wavelength and the signal wavelength of the erbium-doped optical fiber respectively, the intensity of the light beam lambda2 of the signal wavelength is amplified. According to the EDFA module, a fusion welding point between the output optical fiber and the Er-doped optical fiber of a front-end device in a conventional EDFA module is omitted.

Description

Technical Field

[0001] The utility model relates to the field of optical fiber communication, in particular to a single-side fiber output device with isolation, wave combining and signal amplification functions. Background Art

[0002] In the field of optical fiber communication, EDFA is widely used. For conventional EDFA modules, erbium-doped fiber is the key material to achieve the amplification function; in order to input the signal light and pump light into the erbium-doped fiber at the same time and avoid the influence of beam echo, a combiner for combining the signal light and the pump light and an isolator for reverse light isolation are usually configured at the front end of the erbium-doped fiber, and an isolator for reverse light isolation is also configured at the back end of the erbium-doped fiber, that is, a total of three functionally discrete devices are required before and after the erbium-doped fiber in an EDFA module, such as Figure 1 As the optical fiber communication market develops rapidly, the package size of EDFA modules is shrinking, the assembly space for components in the module is getting smaller and smaller, and the requirements for module indicators are becoming more and more stringent. The traditional assembly of three discrete components will not only occupy a large amount of space in the module, but also introduce at least three optical fiber melting points (such as Figure 1 As shown in the figure, the module index is degraded, and the arrangement of components inside the module is limited due to the need to protect the melting point. Therefore, this multi-component assembly solution has gradually failed to meet the industry's requirements for miniaturized modules in terms of component volume and overall index.

[0003] Small EDFA modules have been looking for solutions with smaller size and better performance. The current conventional idea is to use devices that integrate multiple functions to replace three discrete function devices, so as to reduce the number of fusion points, reduce the total volume of devices, and improve module performance, such as: 1) a single-sided / double-sided IWDM integrated device and a single-sided / double-sided isolator; 2) a single-sided / double-sided WDM device and a single-sided / double-sided 2-in-1 isolator; 3) IWDM+ISO double-sided integrated device. However, even if the number of devices is reduced, the fiber fusion points can only be reduced to 2, and the fusion points between the output fiber of the front-end device and the erbium-doped fiber and the fusion points between the input fiber of the back-end device and the erbium-doped fiber cannot be avoided. Summary of the invention

[0004] The utility model aims to provide a single-side fiber output device with isolation, wave combining and signal amplification functions.

[0005] The technical solution adopted by the utility model is:

[0006] A single-side fiber-outlet device with isolation, wave combining and signal amplification functions, comprising an optical fiber head, a light splitting / combining device, a λ1 optical rotation device, a λ2 optical rotation device, a lens, a Faraday optical rotation device, and a wedge-angle reflector;

[0007] The optical fiber head is composed of three optical fibers, namely, a λ1 input optical fiber, a λ2 input optical fiber and an output optical fiber; the wavelength of the λ1 light beam of the λ1 input optical fiber is not equal to the wavelength of the λ2 light beam of the λ2 input optical fiber; the three optical fibers are closely arranged and constructed to form an optical fiber head with an optical fiber inclined surface;

[0008] The light splitting / combining device is a displacement type birefringent crystal; the light splitting / combining device is a displacement type birefringent crystal; one end of the birefringent crystal is in close contact with the inclined surface of the optical fiber head, the optical axis of the birefringent crystal forms a 45° angle with the normal of the incident surface, and the main cross section of the crystal formed by the optical axis and the normal of the incident surface is perpendicular to the inclined surface of the optical fiber head;

[0009] The end faces of both ends of the light splitting / combining device are parallel to each other, the λ1 optical rotation device and the λ2 optical rotation device are closely arranged at the other end of the light splitting / combining device, and the positions of the λ1 optical rotation device and the λ2 optical rotation device correspond to the λ1 input optical fiber and the λ2 input optical fiber respectively; the λ1 optical rotation device adopts a λ1 input wave plate to transmit the λ1 light beam, and the λ2 optical rotation device adopts a λ2 input wave plate to transmit the λ2 light beam;

[0010] One end of the lens has a lens inclined surface parallel to the optical fiber inclined surface, and the lens inclined surface is arranged close to the birefringent crystal; the lens inclined surface is coated with an AR film for the λ1 beam and the λ2 beam; the end face of the other end of the lens is coated with a WDM film, and the WDM film reflects the λ1 beam and transmits the λ2 beam;

[0011] The Faraday rotator is arranged at the other end of the lens. Both ends of the Faraday rotator are vertical planes. The vertical planes at both ends are coated with AR films of the wavelength of the λ2 light beam. Under the action of the saturated magnetic field, the Faraday rotator rotates the polarization direction of the light. The polarization rotation angle is 22.5°, and the rotation direction is the same as the rotation direction of the polarization of the λ2 input wave plate.

[0012] One end of the wedge angle reflector is a vertical plane, and the other end of the wedge angle reflector is a wedge angle surface. One end plane of the wedge angle reflector is arranged close to the Faraday rotation device, one end plane of the wedge angle reflector is coated with an AR film of the λ2 light beam, and the wedge angle surface of the wedge angle reflector is coated with an HR film of the wavelength of the λ2 light beam.

[0013] Furthermore, the three optical fibers are closely arranged in an equilateral triangle, or the three optical fibers are closely arranged in a straight line.

[0014] Specifically, the λ1 input fiber, λ2 input fiber, and output fiber in the optical fiber head are closely arranged in an equilateral triangle, and the spacing between them is greater than or equal to the fiber cladding diameter; the center of the equilateral triangle is the center of the optical fiber inclined surface; among them, the λ1 input fiber is close to the lower end of the optical fiber inclined surface, and the λ2 input fiber is close to the high end of the optical fiber inclined surface.

[0015] Optionally, the λ1 input fiber, λ2 input fiber, and output fiber in the optical fiber head are closely arranged in an isosceles right triangle, and the waist length of the triangle is greater than or equal to the fiber cladding diameter; the midpoint of the base of the triangle is the center of the inclined surface of the optical fiber; wherein the λ1 input fiber is close to the lower end of the inclined surface of the optical fiber, and the λ2 input fiber is close to the higher end of the inclined surface of the optical fiber.

[0016] Optionally, the λ1 input fiber, λ2 input fiber, and output fiber in the optical fiber head are closely arranged in a straight line, and the distance between them is greater than or equal to the fiber cladding diameter; the center position of the straight line is the center of the inclined surface of the optical fiber; the λ1 input fiber is close to the lower end of the optical fiber inclined surface, the λ2 input fiber is close to the high end of the optical fiber inclined surface, and the output fiber is located in the center.

[0017] Furthermore, the output optical fiber in the optical fiber head is an erbium-doped optical fiber. When the λ1 light beam and the λ2 light beam are simultaneously and separately input into the corresponding input optical fibers, the two wavelengths are simultaneously output from the output optical fiber; and when the simultaneously input λ1 light beam and the λ2 light beam are respectively the pump wavelength and the signal wavelength of the erbium-doped optical fiber, the intensity of the λ1 light beam is attenuated by the erbium-doped optical fiber, and the intensity of the λ2 light beam is amplified by the erbium-doped optical fiber.

[0018] Optionally, the output optical fiber in the optical fiber head is an optical fiber doped with other rare earth elements.

[0019] Further, the birefringent crystal is coaxially parallel to the optical fiber head.

[0020] Furthermore, the Faraday rotation device is a combination of a magneto-optical crystal and a magnetic field device or a single magneto-optical crystal.

[0021] Furthermore, the magnetic field device is a permanent magnet, a magnetic ring or a parallel plate made of magnetic material, which is used to provide a saturation magnetic field strength for the magneto-optical crystal, so that the magneto-optical crystal can achieve fixed rotation of the polarization direction of linearly polarized light; the direction of the magnetic field is parallel to the direction of light propagation; when the linearly polarized light is incident from the magnetic field level N of the magnetic field device, the polarization direction rotates clockwise; when the linearly polarized light is incident from the magnetic field level S, the polarization direction rotates counterclockwise.

[0022] Optionally, one side of the magneto-optical crystal close to the lens is coated with a high-reflection film of λ1, and the other side is coated with an anti-reflection film of λ2.

[0023] Further, as an implementation mode, a vertical plane at one end of the Faraday rotator is arranged close to the other end of the lens.

[0024] Further, as another implementation, a vertical plane at one end of the Faraday rotator is spaced apart from the other end of the lens.

[0025] Further, the wavelength of the λ1 light beam is smaller than the wavelength of the λ2 light beam.

[0026] Specifically, when the λ1 light beam is input from the λ1 input optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ1 optical rotation device, and the lens in sequence, and is reflected on the WDM film of the lens, and finally outputs from the output optical fiber in the optical fiber head; or when the λ1 light beam is input from the output optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ1 optical rotation device, and the lens in sequence, and is reflected on the WDM film of the lens, and finally outputs from the λ1 input optical fiber in the optical fiber head;

[0027] The λ2 light beam is inputted from the λ2 input optical fiber in the optical fiber head, passes through the light splitting / combining device, the λ2 optical rotation device, the lens, the Faraday optical rotation device, the wedge angle reflector, is reflected on the wedge angle surface of the wedge angle reflector, and is finally outputted from the output optical fiber in the optical fiber head;

[0028] Furthermore, when the λ1 light beam and the λ2 light beam are simultaneously and separately input into the corresponding input optical fibers, the two wavelengths are simultaneously output from the output optical fibers, thus realizing the wavelength combining function.

[0029] Furthermore, when the λ2 light beam is input from the output optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ2 optical rotation device, the lens, the Faraday optical rotation device, and the wedge-angle reflector, and is reflected on the wedge-angle surface of the wedge-angle reflector, and finally cannot be output from the λ2 input optical fiber in the optical fiber head, that is, the isolation function is realized;

[0030] Further, as a possible implementation, the inclination angle of the optical fiber inclined surface in the optical fiber head is 8°.

[0031] Furthermore, the lens is a self-focusing lens, the other end of the lens is a vertical plane, one end of the lens is a lens inclined surface, and the inclination angle of the lens inclined surface of the lens is 8°.

[0032] Optionally, the lens is a cylindrical spherical lens, the other end of the lens is a spherical surface, one end of the lens is a lens inclined surface, and the inclination angle of the lens inclined surface is 8°; the lens inclined surface and the spherical surface of the lens are coated with anti-reflection films of λ1 and λ2.

[0033] Furthermore, the birefringent crystal is used to realize the splitting / combining of o-light and e-light in the crystal; the optical axis of the birefringent crystal is oblique to the crystal surface, and the separation direction of o-light and e-light is perpendicular to the propagation direction of the light beam and parallel to the relative displacement direction of the λ1 input optical fiber, the λ2 input optical fiber and the output optical fiber.

[0034] Optionally, the optical axis angle of the o-light and the e-light of the birefringent crystal is 45 degrees, and when the thickness of the crystal is consistent, the separation distance of the o-light and the e-light is the largest.

[0035] Furthermore, the λ1 input wave plate in the λ1 optical rotation device is a 1 / 2λ phase delay type quartz wave plate crystal, and the λ1 optical rotation device is used to rotate the polarization direction of linear polarized light; the angle between the optical axis of the quartz wave plate crystal of the λ1 optical rotation device and the crystal surface is 45 degrees; the λ2 input wave plate in the λ2 optical rotation device is a 1 / 2λ phase delay type quartz wave plate crystal, and the λ2 optical rotation device is used to rotate the polarization direction of linear polarized light; the angle between the optical axis of the quartz wave plate crystal of the λ2 optical rotation device and the crystal surface is 67.5 degrees.

[0036] The utility model adopts the above technical scheme and integrates the functions of isolation, combining and signal amplification: the reflective optical path design of splitting / combining makes the length and diameter of the device smaller than those of integrated devices with similar functions; the single-sided fiber output design provides a higher degree of freedom for the arrangement of devices in the module; in the application of EDFA, the design of erbium-doped optical fiber as the output optical fiber can save a fusion point between the device and the erbium-doped optical fiber, and there is no need to design special fusion point protection, which can also provide a higher degree of freedom for the arrangement of devices inside the module.

[0037] The beneficial effects of the utility model include: firstly, by adopting a reflector to realize the light deflection, the device only needs one collimator, which reduces one collimator compared with the bilateral device, reduces the volume of the device by half, reduces the space required for assembly in the module by half, and reduces the material cost accordingly; secondly, the two input optical fibers and the output optical fiber are located on the same side of the device, and the single-side winding can be performed simultaneously when assembled in the module, which simplifies the winding assembly process; at the same time, by fixing the light splitting / combining device on the end face of the input / output optical fiber, the utility model has stronger control over the input / output and higher functional expandability, and the volume required for the light splitting / combining device is smaller, making the structure more compact and the material cost lower; and, when the erbium-doped optical fiber is used as the output optical fiber, when λ1 and λ2 are input at the same time, the device has a signal amplification function and can be directly applied to the EDFA module, eliminating one melting point protection device, and providing a higher degree of freedom for the arrangement of the devices inside the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods;

[0039] Figure 1 This is a schematic diagram of the optical path before and after the DFA erbium fiber;

[0040] Figure 2 This is a schematic diagram of three optical fibers closely arranged in an equilateral triangle according to the present invention;

[0041] Figure 3 This is a schematic diagram of the optical path structure of Embodiment 1 of the present invention;

[0042] Figure 4Schematic diagram of the optical path structure of the second embodiment of the present invention.

[0043] Figure numerals: optical fiber head-1, light splitting / combining device-2, λ1 optical rotation device-3, λ2 optical rotation device-4, lens-5, Faraday optical rotation device-6, wedge angle reflector-7, input optical fiber-8, λ2 input optical fiber-9, output optical fiber-10. Implementation

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0045] like Figures 2 to 4 As shown in FIG. 1 , the utility model discloses a single-side fiber output device with isolation, wave combining and signal amplification functions. Figures 2 to 4 Since the optical fibers in the optical fiber head can be arranged in a variety of ways, such as triangular, square or linear, in order to more clearly express the present invention, the following implementation will take the triangular shape as an example; the Faraday rotation device can be a combination of a magneto-optical crystal and a permanent magnet or a single magneto-optical crystal, and the following implementation will take the single magneto-optical crystal as an example; the two implementation cases of the present invention will respectively adopt a self-focusing lens and a cylindrical spherical lens; in addition, the wavelength of the λ1 beam in the embodiment is 980nm, and that of the λ2 beam is 1550nm. Embodiment 1

[0046] See also Figure 2 and Figure 3 As shown, a single-side fiber-outlet device with isolation, wave combining and signal amplification functions in Embodiment 1 adopts the following technical solution: the structure includes an optical fiber head 1, a light splitting / combining device 2, a λ1 optical rotation device 3, a λ2 optical rotation device 4, a lens 5, a Faraday optical rotation device 6, and a wedge angle reflector 7;

[0047] The optical fiber head 1 is composed of three functional optical fibers, namely, the λ1 input optical fiber 8, the λ2 input optical fiber 9, and the output optical fiber 10; the three optical fibers are closely arranged in an equilateral triangle, and the three constitute the optical fiber head 1 with an inclined surface, and the subsequent devices are placed in sequence close to the inclined surface; the output optical fiber is an erbium-doped optical fiber;

[0048] The light splitting / combining device 2 is a displacement type birefringent crystal; the crystal is coaxially parallel to the optical fiber head 1 and is in close contact with the inclined surface of the optical fiber head 1. The optical axis of the birefringent crystal forms a 45° angle with the normal of the incident surface, and the main cross section of the crystal formed by the optical axis and the normal of the incident surface is perpendicular to the inclined surface of the optical fiber head 1; the o-light and e-light generated by birefringence are separated by 0.02mm on the main cross section of the crystal, and the e-light deviates toward the lower end of the optical fiber head 1;

[0049] The λ1 optical rotation device 3 is a λ1 input wave plate, and its position corresponds to the λ1 input optical fiber 8, and is close to the light splitting / combining device 2. The λ1 input wave plate transmits a 980nm light beam, and the angle between the optical axis and the crystal surface is 45 degrees;

[0050] The λ2 optical rotation device 4 is a λ2 input wave plate, and its position corresponds to the λ2 input optical fiber 9, and is close to the light splitting / combining device 2. The λ2 input wave plate transmits a 1550nm light beam, and the angle between the optical axis and the crystal surface is 67.5 degrees;

[0051] A self-focusing lens 5, one end of which is an inclined surface and the other end is a plane, the inclined surface is parallel to the inclined surface of the optical fiber head 1 and is close to the light splitting / combining device, the inclined surface is coated with an AR film with a wavelength of 980nm and a wavelength of 1550nm, and the plane is coated with a WDM film, the WDM film reflects the 980nm wavelength and transmits the 1550nm wavelength;

[0052] The Faraday rotation device 6 is a separate magneto-optical crystal; both ends of the magneto-optical crystal are planes, and both end planes are coated with an AR film with a wavelength of 1550nm. Under the action of a saturated magnetic field, the magneto-optical crystal can rotate the polarization direction of linearly polarized light, and the polarization rotation angle is 22.5°, and the rotation direction is the same as the rotation direction of the polarization of the λ2 input wave plate; the permanent magnet is a magnetic ring or a parallel plate made of a magnetic material;

[0053] A wedge angle reflector 7, one end of which is a plane and the other end is a wedge angle surface, the plane is close to the Faraday rotator, the plane is coated with an AR film of the λ2 beam, and the wedge angle surface is coated with an HR film of the wavelength of the λ2 beam;

[0054] The forward optical path of the 980nm wavelength light beam is as follows: when the 980nm wavelength light beam is input from the λ1 input optical fiber 8 in the optical fiber head 1, it passes through the light splitting / combining device 2, the λ1 optical rotation device 3, and the lens 5 in sequence, and is reflected on the WDM film of the lens 5, and finally output from the output optical fiber 10 in the optical fiber head 1;

[0055] The reverse optical path of the 980nm wavelength light beam is as follows: when the 980nm wavelength light beam is input from the output optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ1 optical rotation device, and the lens in sequence, and is reflected on the WDM film of the lens, and finally output from the λ1 input optical fiber in the optical fiber head;

[0056] The forward optical path of the light beam with a wavelength of 1550 nm is as follows: the light beam with a wavelength of 1550 nm is input from the λ2 input optical fiber 9 in the optical fiber head 1, passes through the light splitting / combining device 2, the λ2 optical rotation device 4, the lens 5, the Faraday optical rotation device 6, and the wedge angle reflector 7, is reflected on the wedge angle surface of the wedge angle reflector 7, and is finally output from the output optical fiber 10 in the optical fiber head 1;

[0057] The reverse optical path of the light beam with a wavelength of 1550 nm is as follows: the light beam with a wavelength of 1550 nm is input from the output optical fiber 10 in the optical fiber head 1, passes through the light splitting / combining device 2, the λ2 optical rotation device 4, the lens 5, the Faraday optical rotation device 6, and the wedge angle reflector 7, and then is reflected on the wedge angle surface of the wedge angle reflector 7, and finally cannot be output from the λ2 input optical fiber 9 in the optical fiber head 1;

[0058] When a light beam with a wavelength of 980 nm and a light beam with a wavelength of 1550 nm are simultaneously input through the corresponding forward optical path, the two wavelengths can be simultaneously output from the output optical fiber 10, and the function is the wavelength combining function;

[0059] When a light beam with a wavelength of 1550nm is input through the corresponding forward optical path, it can be output from the output optical fiber 10; when a light beam with a wavelength of 1550nm is input through the corresponding reverse optical path, it cannot be output from the corresponding λ2 input optical fiber 9; the function is the isolation function;

[0060] When a light beam with a wavelength of 980nm and a light beam with a wavelength of 1550nm are simultaneously input through the corresponding forward optical path, they can be simultaneously output from the output optical fiber 10, and the intensity of the light beam with a wavelength of 980nm will be attenuated by the erbium-doped optical fiber, and the intensity of the light beam with a wavelength of 1550nm will be amplified by the erbium-doped optical fiber; the function is the signal amplification function; Embodiment 2

[0061] The main difference between the second embodiment and the first embodiment is that the lens 5 of the first embodiment is a self-focusing lens, while the lens 5 of the second embodiment is a cylindrical spherical lens. Figure 4 As shown; since the spherical surface of the cylindrical spherical lens cannot be coated and bonded to the rotating sheet, the corresponding structural design changes are as follows Figure 4 , the coating scheme changes are as follows:

[0062] The cylindrical spherical lens 5 has an inclined surface at one end and a spherical surface at the other end; the inclined surface is coated with AR films with wavelengths of 980nm and 1550nm.

[0063] The Faraday rotator 6 is a separate magneto-optical crystal; both ends of the magneto-optical crystal are flat, and the plane close to the lens is coated with a WDM film, which reflects the 980nm wavelength and transmits the 1550nm wavelength; the plane away from the lens is coated with an anti-reflection film with a wavelength of 1550nm.

[0064] By changing the self-focusing lens to a cylindrical spherical lens, the sensitivity to the polarization-related insertion loss PDL of the 1550nm wavelength will be significantly improved. An important component in the reflection optical path of the 1550nm wavelength light beam is the wedge-angle reflector 7, which needs to be fixed by angle bonding after debugging. When the relative angular position at this position changes, the insertion loss of the IL of the 1550nm wavelength light beam will deteriorate significantly, accompanied by a significant degradation of the PDL of the 1550nm wavelength light beam. In the optical path containing the self-focusing lens 5, when the angle changes by 0.05°, the PDL index of the 1550nm wavelength will deteriorate to 0.21dB; in the optical path containing the cylindrical spherical lens, when the angle changes by 0.05°, the PDL index of the 1550nm wavelength will deteriorate to 0.95dB.

[0065] The single-sided fiber-outlet device of the utility model has the following functional characteristics: through the reflection optical path design of splitting / combining light, the isolation and combining functions are integrated in one device, and the length and diameter of the device are smaller than the module with the same function; the input optical fiber and the output optical fiber are located on the same side of the device, which provides a higher degree of freedom for the arrangement of the devices inside the module; the erbium-doped optical fiber is used as the output optical fiber, which eliminates the fusion point between the combining device and the erbium-doped optical fiber inside the module, and there is no need to design a special fusion point protection, which also provides a higher degree of freedom for the arrangement of the devices inside the module.

[0066] The beneficial effects of the utility model include: firstly, by adopting a reflector to realize the light deflection, the device only needs one collimator, which reduces one collimator compared with the bilateral device, reduces the volume of the device by half, reduces the space required for assembly in the module by half, and reduces the material cost accordingly; secondly, the two input optical fibers and the output optical fiber are located on the same side of the device, and the single-side winding can be performed simultaneously when assembled in the module, which simplifies the winding assembly process; at the same time, by fixing the light splitting / combining device on the end face of the input / output optical fiber, the utility model has stronger control over the input / output and higher functional expandability, and the volume required for the light splitting / combining device is smaller, making the structure more compact and the material cost lower; and, when the erbium-doped optical fiber is used as the output optical fiber, when λ1 and λ2 are input at the same time, the device has a signal amplification function and can be directly applied to the EDFA module, eliminating one melting point protection device, and providing a higher degree of freedom for the arrangement of the devices inside the module.

[0067] Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians of the art without making creative work are within the scope of protection of the present application.

Claims

1. A single-side fiber output device with isolation, wave combining and signal amplification functions, characterized in that: It includes an optical fiber head, a light splitting / combining device, a λ1 optical rotation device, a λ2 optical rotation device, a lens, a Faraday optical rotation device and a wedge angle reflector; The optical fiber head is composed of three optical fibers, namely, a λ1 input optical fiber, a λ2 input optical fiber and an output optical fiber; the wavelength of the λ1 light beam of the λ1 input optical fiber is not equal to the wavelength of the λ2 light beam of the λ2 input optical fiber; the three optical fibers are closely arranged and constructed to form an optical fiber head with an optical fiber inclined surface; The light splitting / combining device is a displacement type birefringent crystal; the light splitting / combining device is a displacement type birefringent crystal; one end of the birefringent crystal is in close contact with the inclined surface of the optical fiber head, the optical axis of the birefringent crystal forms a 45° angle with the normal of the incident surface, and the main cross section of the crystal formed by the optical axis and the normal of the incident surface is perpendicular to the inclined surface of the optical fiber head; The end faces of both ends of the light splitting / combining device are parallel to each other, the λ1 optical rotation device and the λ2 optical rotation device are closely arranged at the other end of the light splitting / combining device, and the positions of the λ1 optical rotation device and the λ2 optical rotation device correspond to the λ1 input optical fiber and the λ2 input optical fiber respectively; the λ1 optical rotation device adopts a λ1 input wave plate to transmit the λ1 light beam, and the λ2 optical rotation device adopts a λ2 input wave plate to transmit the λ2 light beam; One end of the lens has a lens inclined surface parallel to the optical fiber inclined surface, and the lens inclined surface is arranged close to the birefringent crystal; the lens inclined surface is coated with an AR film for the λ1 beam and the λ2 beam; the end face of the other end of the lens is coated with a WDM film, and the WDM film reflects the λ1 beam and transmits the λ2 beam; The Faraday rotator is arranged at the other end of the lens. Both ends of the Faraday rotator are vertical planes. The vertical planes at both ends are coated with AR films of the wavelength of the λ2 light beam. Under the action of the saturated magnetic field, the Faraday rotator rotates the polarization direction of the light. The polarization rotation angle is 22.5°, and the rotation direction is the same as the rotation direction of the polarization of the λ2 input wave plate. One end of the wedge angle reflector is a vertical plane, and the other end of the wedge angle reflector is a wedge angle surface. One end plane of the wedge angle reflector is arranged close to the Faraday rotation device, one end plane of the wedge angle reflector is coated with an AR film of the λ2 light beam, and the wedge angle surface of the wedge angle reflector is coated with an HR film of the wavelength of the λ2 light beam.

2. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The λ1 input fiber, λ2 input fiber, and output fiber in the fiber head are closely arranged in an equilateral triangle, and the spacing between them is greater than or equal to the fiber cladding diameter; the center of the equilateral triangle is the center of the fiber inclined surface; the λ1 input fiber is close to the lower end of the fiber inclined surface, and the λ2 input fiber is close to the higher end of the fiber inclined surface; Alternatively, the λ1 input fiber, the λ2 input fiber, and the output fiber in the optical fiber head are closely arranged in an isosceles right triangle, and the waist length of the triangle is greater than or equal to the fiber cladding diameter; the midpoint of the base of the triangle is the center of the inclined surface of the optical fiber; the λ1 input fiber is close to the lower end of the optical fiber inclined surface, and the λ2 input fiber is close to the higher end of the optical fiber inclined surface; Alternatively, the λ1 input fiber, λ2 input fiber, and output fiber in the optical fiber head are closely arranged in a straight line, and the distance between them is greater than or equal to the fiber cladding diameter; the center position of the straight line is the center of the inclined surface of the optical fiber; among them, the λ1 input fiber is close to the lower end of the optical fiber inclined surface, the λ2 input fiber is close to the higher end of the optical fiber inclined surface, and the output fiber is located in the center.

3. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The output optical fiber in the optical fiber head is an erbium-doped optical fiber. When the λ1 light beam and the λ2 light beam are simultaneously and separately input into the corresponding input optical fibers, the two wavelengths are simultaneously output from the output optical fiber; and when the simultaneously input λ1 light beam and the λ2 light beam are respectively the pump wavelength and the signal wavelength of the erbium-doped optical fiber, the intensity of the λ1 light beam is attenuated by the erbium-doped optical fiber, and the intensity of the λ2 light beam is amplified by the erbium-doped optical fiber.

4. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The Faraday rotation device is a combination of a magneto-optical crystal and a magnetic field device or a single magneto-optical crystal; the magnetic field device is a permanent magnet, and the magnetic field device is a magnetic ring or a parallel plate made of magnetic material, which is used to provide the saturation magnetic field intensity of the magneto-optical crystal so that the magneto-optical crystal can realize fixed rotation of the polarization direction of linearly polarized light; the direction of the magnetic field is parallel to the direction of light propagation; when the linearly polarized light is incident from the magnetic field level N of the magnetic field device, the polarization direction rotates clockwise; when the linearly polarized light is incident from the magnetic field level S, the polarization direction rotates counterclockwise.

5. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 4, characterized in that: The side of the magneto-optical crystal close to the lens is coated with a λ1 high-reflection film, and the other side is coated with a λ2 anti-reflection film.

6. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: A vertical plane at one end of the Faraday rotator is arranged close to the other end of the lens; or a vertical plane at one end of the Faraday rotator is arranged at an interval from the other end of the lens.

7. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The wavelength of the λ1 light beam is smaller than the wavelength of the λ2 light beam; when the λ1 light beam is input from the λ1 optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ1 optical rotation device, and the lens in sequence, and then is reflected on the WDM film of the lens, and finally is output from the output optical fiber in the optical fiber head; or when the λ1 light beam is input from the output optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ1 optical rotation device, and the lens in sequence, and then is reflected on the WDM film of the lens, and finally is output from the λ1 input optical fiber in the optical fiber head; When the λ2 light beam is input from the λ2 input fiber in the fiber head, it passes through the light splitting / combining device, the λ2 optical rotation device, the lens, the Faraday optical rotation device, the wedge angle reflector, and is reflected on the wedge angle surface of the wedge angle reflector, and finally output from the output fiber in the fiber head; When the λ1 beam and the λ2 beam are input into the corresponding input optical fiber simultaneously and separately, the two wavelengths are output from the output optical fiber at the same time, thus realizing the wavelength combining function; When the λ2 light beam is input from the output optical fiber in the optical fiber head, it passes through the light splitting / combining device, the λ2 optical rotation device, the lens, the Faraday optical rotation device, and the wedge-angle reflector, and is reflected on the wedge-angle surface of the wedge-angle reflector. Finally, it cannot be output from the λ2 input optical fiber in the optical fiber head, thus realizing the isolation function.

8. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The inclination angle of the optical fiber inclined surface in the optical fiber head is 8°; the lens is a self-focusing lens, the other end of the lens is a vertical plane, one end of the lens is a lens inclined surface, and the inclination angle of the lens inclined surface of the lens is 8°; or the lens is a cylindrical spherical lens, the other end of the lens is a spherical surface, one end of the lens is a lens inclined surface, and the inclination angle of the lens inclined surface is 8°; the lens inclined surface and spherical surface of the lens are coated with anti-reflection films of λ1 and λ2.

9. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The birefringent crystal is used to realize the splitting / combining of o-light and e-light in the crystal; the optical axis of the birefringent crystal is oblique to the crystal surface, and the separation direction of o-light and e-light is perpendicular to the propagation direction of the light beam and parallel to the relative displacement direction of the λ1 input fiber, the λ2 input fiber and the output fiber.

10. The single-side fiber output device with isolation, wave combining and signal amplification functions according to claim 1, characterized in that: The λ1 input wave plate in the λ1 optical rotator is a 1 / 2λ phase-delay quartz wave plate crystal, and the λ1 optical rotator is used to rotate the polarization direction of linear polarized light; the angle between the optical axis of the quartz wave plate crystal of the λ1 optical rotator and the crystal surface is 45 degrees; the λ2 input wave plate in the λ2 optical rotator is a 1 / 2λ phase-delay quartz wave plate crystal, and the λ2 optical rotator is used to rotate the polarization direction of linear polarized light; the angle between the optical axis of the quartz wave plate crystal of the λ2 optical rotator and the crystal surface is 67.5 degrees.

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