Coupler and optical fiber amplifier

Abstract

The invention provides a coupler and an optical fiber amplifier, relates to the technical field of communication equipment, and aims to at least solve the problem of low coupling efficiency. The coupler comprises a first end and a second end which are oppositely arranged, and at least two first air cavities penetrating through the first end and a second air cavity penetrating through the second end are formed in the coupler. Wherein at least two first air cavities are communicated with the second air cavity. The optical signal is transmitted from one end of the coupler to the other end through the first air cavity and the second air cavity, so that a specific transmission channel is provided for the optical signal, the transmission medium is air, the coupling loss is reduced, and the coupling efficiency is improved. Multiple groups of signals enter the coupler through the different first air cavities and are coupled in the second air cavity, so that coupling of the multiple groups of signals is realized, and the overall coupling efficiency of the signals from input to output is improved.

Description

Technical Field

[0001] The present application relates to the technical field of communication equipment, and in particular to a coupler and an optical fiber amplifier. Background Art

[0002] As the Internet has developed rapidly and the amount of data communication has increased, this change has further increased the transmission distance requirements of optical fiber communication systems, and accordingly, has also put forward more stringent requirements on the performance of optical fiber amplifiers. The principle of optical fiber amplifiers is to couple signal light and pump light through a coupler, and then stimulate amplification by other parts.

[0003] Pump light is transmitted through hollow core optical fibers, so a coupler that can adapt to hollow core optical fibers is required. In the prior art, the side surfaces of two hollow core optical fibers are polished, and then the polished surfaces of the two optical fibers are attached to each other, and then the optical fiber coupler is formed by melting or taper.

[0004] The coupler in the prior art has high requirements on the process and low coupling efficiency. Summary of the invention

[0005] The present application provides a coupler and an optical fiber amplifier to at least solve the problem of low coupling efficiency.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, a coupler is provided. The coupler comprises a first end and a second end arranged opposite to each other, and at least two first air cavities passing through the first end and a second air cavity passing through the second end are arranged in the coupler, wherein at least two first air cavities are connected to the second air cavity.

[0008] When the optical signal is propagating, different propagation media have different refractive indices, and the refractive index will affect the propagation path and energy distribution of the light. By setting the first air cavity and the second air cavity, the optical signal is propagated from one end of the coupler to the other end, thereby providing a specific transmission channel for the optical signal, and the transmission medium is air, which reduces coupling loss and improves coupling efficiency. At the same time, by setting at least two first air cavities and the second air cavity in communication, multiple groups of signals enter the coupler through different first air cavities and couple in the second air cavity, realizing the coupling of multiple groups of signals, thereby improving the overall coupling efficiency of the signal from input to output.

[0009] In a possible implementation, the coupler includes a cylindrical main body and a partition. The cylindrical main body includes a first main body section and a second main body section. The partition is located in the first main body section and connected to the first main body section, and the partition and the first main body section enclose at least two first air cavities. The second air cavity is located in the second main body section.

[0010] In a possible implementation, there are two partitions, the two partitions are arranged at intervals, and the two partitions and the inner wall surface of the first main body segment form two first air cavities.

[0011] In a possible implementation, both of the two first air cavities are connected to the space between the two partitions. The cross-sectional area of ​​one of the two first air cavities is greater than or equal to the cross-sectional area of ​​the other air cavity.

[0012] In a possible embodiment, at least two main body air cavities are provided in the cylindrical main body portion, penetrating the first end and the second end. Along the radial direction of the cylindrical main body portion, the at least two main body air cavities are spaced apart from the at least two first air cavities, and the at least two main body air cavities are spaced apart from the second air cavities.

[0013] In a possible implementation, the cylindrical main body includes a plurality of connecting tubes penetrating the first end and the second end, a main body air cavity is provided in a connecting tube, and the plurality of connecting tubes and the partitioning portion enclose at least two first air cavities and a second air cavity.

[0014] In a second aspect, a fiber amplifier is provided, comprising: a first coupler, an input source, and an output source. The first coupler comprises a coupler provided by any one of the embodiments of the first aspect. The input source is connected to a first end of the coupler in the first coupler. The output source is connected to a second end of the coupler in the first coupler.

[0015] In a possible implementation, the first coupler includes a first interface and a second interface located at the first end. The first interface is connected to a first air cavity, and the second interface is connected to another first air cavity. The input source includes a pump source, which is connected to the first interface. The input source also includes a signal source, which is connected to the second interface.

[0016] In a possible implementation, the first interface is connected to the second interface to form a connection interface. The optical fiber amplifier also includes a first hollow-core optical fiber, one end of the first hollow-core optical fiber is connected to the pump source, and the other end is connected to the first interface; the diameter of the first hollow-core optical fiber is greater than half of the maximum width of the connection interface and less than the radius of the coupler.

[0017] In a possible implementation, the area of ​​the first interface is equal to the area of ​​the second interface. The optical fiber amplifier further includes a signal optical fiber, one end of which is connected to the signal source, and the other end of which is connected to the second interface. The radius of the signal optical fiber is the same as that of the first hollow-core optical fiber.

[0018] In a possible implementation, the output source includes a first output source and a second output source arranged in series; the first output source is connected to the second end of the coupler in the first coupler;

[0019] The optical fiber amplifier further includes a second coupler, the second coupler includes the coupler provided by any one of the embodiments of the first aspect; the second coupler further includes a third interface and a fourth interface located at the first end of the coupler. The second end of the coupler in the second coupler is connected to the pump source, the third interface is connected to the first interface; and the fourth interface is connected to the second output source.

[0020] In a possible implementation, the optical fiber amplifier further includes a third coupler. The third coupler includes the coupler provided by any one of the embodiments of the first aspect, and the third coupler further includes a fifth interface and a sixth interface located at the first end of the coupler, and the third coupler is located between the first output source and the second output source. The sixth interface is connected to the first output source. The fifth interface is connected to the fourth interface. The second end of the coupler in the third coupler is connected to the second output source. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a coupler provided in an embodiment of the present application;

[0022] Figure 2 for Figure 1 Schematic diagram of the cross section of the middle coupler along the AA direction;

[0023] Figure 3 A schematic cross-sectional view of a coupler along the BB direction provided by an embodiment;

[0024] Figure 4 A schematic cross-sectional view of a coupler along the BB direction provided in yet another embodiment;

[0025] Figure 5 A schematic cross-sectional view of a coupler along the BB direction provided by another embodiment;

[0026] Figure 6 A schematic cross-sectional view of a coupler along the BB direction provided in another embodiment;

[0027] Figure 7 A schematic diagram of the structure of an optical fiber amplifier provided in an embodiment of the present application;

[0028] Figure 8 One of the schematic diagrams of the first coupler connection structure provided in an embodiment of the present application;

[0029] Fig. 9 A second schematic diagram of a first coupler connection structure provided in an embodiment of the present application;

[0030] Fig.10 A schematic diagram of the structure of another optical fiber amplifier provided in an embodiment of the present application.

[0031] Reference numerals: 100 - coupler; 200 - optical fiber amplifier;

[0032] 1-first end; 2-second end; 3-first air cavity; 4-second air cavity; 5-cylindrical main body; 51-first main body section; 52-second main body section; 53-main body air cavity; 6-partition; 7-connecting pipe;

[0033] 01-first coupler; 011-first interface; 012-second interface; 013-connection interface; 02-input source; 021-pump source; 022-signal source; 03-output source; 031-first output source; 032-second output source; 04-first hollow-core fiber; 05-signal fiber; 06-second hollow-core fiber;

[0034] 07-second coupler; 071-third interface; 072-fourth interface;

[0035] 08-third coupler; 081-fifth interface; 082-sixth interface. DETAILED DESCRIPTION

[0036] A coupler and an optical fiber amplifier provided in an embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0037] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0038] The terms "first" and "second" and the like in the specification and drawings of this application are used to distinguish different objects, or to distinguish different processing of the same object, rather than to describe a specific order of objects.

[0039] In addition, the terms "including" and "having" and any variations thereof mentioned in the description of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include other steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0040] It should be noted that, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0041] In the description of the present application, unless otherwise specified, “plurality” means two or more.

[0042] In order to facilitate the description of the following embodiments, before introducing the embodiments of the present application, some professional terms to be mentioned in the embodiments of the present application are first introduced, specifically:

[0043] Pumping: Pumping is the process of using light to raise (or "pump") electrons from lower energy levels in atoms or molecules to higher energy levels. Often used in laser structures to pump the lasing medium to achieve population inversion.

[0044] Laser Pumping: Laser pumping is the act of transferring energy from an external source to the laser gain medium. Energy is absorbed in the medium, creating excited states in the atoms. When the number of particles in one excited state exceeds the number of particles in the ground state or less excited states, population inversion is achieved. In this case, the mechanism of stimulated emission can occur and the medium can be used as a laser or optical amplifier. The pump power must be above the lasing threshold of the laser.

[0045] Optical coupling: Optical coupling is the division or combination of optical power of the same wavelength. Through the optical coupler, we can combine two optical signals into one, which is mainly used to transmit signals and realize photoelectric conversion of models.

[0046] Coupling efficiency: In optical fiber transmission, the ratio of the optical power at the input end of the interface to the optical power at the output end. For example, the ratio of the power emitted by the light source to the power received by the optical fiber bundle, or the ratio of the optical power received at the end of the optical fiber bundle to the power falling on the photodetector.

[0047] In recent years, the rapid development of the network has doubled the amount of data communication. As a key network element, the fiber amplifier has put forward more stringent requirements on the fiber amplifier system, and the performance of the fiber amplifier affects the signal transmission distance. When the performance of the fiber amplifier is improved, it can support a longer signal transmission distance, thereby reducing the number of relay stations and reducing costs.

[0048] The working principle of a traditional fiber amplifier is as follows: the fiber amplifier amplifies the optical signal by coupling multiple groups of signals (eg, pump light, signal light, etc.) into the active optical fiber.

[0049] In traditional fiber amplifiers, solid-core fibers are usually used as pump fibers. In order to be highly compatible with common pump light wavelengths (such as 910nm and 976nm) to reduce transmission losses, a thin-core structure is generally used. However, this thin-core fiber cannot carry high-power pump light and is not conducive to multi-order amplification.

[0050] In addition, traditional couplers are generally made using the tapered coupling method, and the diameter of the pump fiber will become smaller, causing a serious decrease in the transmission bandwidth and power carrying capacity, which in turn leads to limited gain improvement of the optical fiber amplifier, increased noise coefficient, and narrower signal amplification band.

[0051] In the related art, the sides of two hollow-core optical fibers are polished, and then the polished surfaces of the two optical fibers are bonded to each other, and then fused or tapered to form an optical fiber coupler. However, the optical fiber coupler formed in this way has high process requirements and low coupling efficiency.

[0052] like Figure 1 and Figure 2 As shown, in the first aspect, in order to at least solve the problem of low coupling efficiency among the above problems, the present application provides a coupler 100 .

[0053] The coupler 100 provided in the present application includes a first end 1 and a second end 2 arranged opposite to each other. The first end 1 and the second end 2 refer to one end of the optical signal input coupler 100 and one end of the optical signal output coupler 100. The first end 1 can be an input end or an output end, and the second end 2 can be an input end or an output end.

[0054] At least two first air cavities 3 penetrating the first end 1 and a second air cavity 4 penetrating the second end 2 are provided in the coupler 100 . The at least two first air cavities 3 are in communication with the second air cavity 4 .

[0055] By setting at least two first air cavities 3 and second air cavities 4 in communication, multiple groups of signals enter the coupler 100 through multiple first air cavities 3, and then complete coupling when entering the second air cavity 4 from the first air cavity 3, thereby achieving coupling of multiple groups of signals. In this process, optical signals complete coupling by propagation, thereby improving the overall coupling efficiency of signals from input to output.

[0056] When the optical signal propagates, different propagation media have different refractive indices, and the refractive index will affect the propagation path and energy distribution of the light. The optical signal is propagated from one end of the coupler 100 to the other end by setting the first air cavity 3 and the second air cavity 4, thereby providing a specific transmission channel for the optical signal, and the transmission medium is air, which reduces coupling loss and improves coupling efficiency.

[0057] At least two first air cavities 3 can simultaneously transmit a plurality of signals of different frequencies or different modes. These signals can be integrated or distributed inside the coupler 100 through communication with the second air cavity 4.

[0058] The structure of the air cavity can play a certain role in signal isolation. Since the dielectric constant of air is relatively stable, the signals have little mutual interference when propagating in the air cavity.

[0059] The embodiments of the present application are described in detail below in conjunction with the accompanying drawings, and before describing the embodiments of the present application in detail, the application scenarios of the embodiments of the present application are first described.

[0060] The coupler 100 provided in the present application can be used in the construction of communication systems, radio frequency circuits, radar systems, and broadcasting and television systems. Specifically, it can be applied to optical communications, fiber optic sensors, fiber optic lasers, wavelength division multiplexing systems, fiber optic networks, power amplifiers, filters, and other scenarios.

[0061] In one possible implementation, see Figure 2 . The coupler 100 includes a cylindrical main body 5. The cylindrical main body 5 refers to a hollow cylindrical structure. The cylindrical main body 5 has a high compressive strength. When subjected to external pressure, its cylindrical shape can effectively disperse the pressure and is less likely to deform than other shaped (such as square) structures. For example, in deep-sea exploration equipment, the cylindrical main body 5 can be used as a pressure-resistant shell.

[0062] In some other embodiments, the coupler 100 includes a main body with a through hole in the middle. The main body may be in a cubic shape, a polygonal prism shape, or an irregular shape.

[0063] The cylindrical body 5 includes a first body section 51 and a second body section 52. The first body section 51 is connected to the second body section 52. Exemplarily, the connection between the first body section 51 and the second body section 52 includes, but is not limited to, welding, fusion, integral molding, plug-in, clamping, or gluing.

[0064] The first air cavity 3 is located in the first main body section 51 , and the second air cavity 4 is located in the second main body section 52 .

[0065] In a possible implementation manner, the coupler 100 further includes a partition 6 . The partition 6 is located in the first main body section 51 and connected to the first main body section 51 .

[0066] Exemplarily, the connection methods between the partition 6 and the first main body section 51 include, but are not limited to: welding, fusion, integral molding, plug-in, snap-on, or gluing.

[0067] The partition 6 and the first main body section 51 enclose at least two first air cavities 3. A plurality of independent first air cavities 3 can be formed by setting the partition 6, for example, the partition 6 can divide the space in the first main body section 51 into at least two first air cavities 3.

[0068] By setting the partition 6, the size, shape and direction of each first air cavity 3 can be controlled, which has the effect of optimizing the signal transmission path. For example, for high-frequency signals, the partition 6 can adjust the impedance matching of the signal by changing the size and shape of the first air cavity 3. Appropriate impedance matching can reduce signal reflection and improve signal transmission efficiency. In the radio frequency circuit, the partition 6 can form a microstrip line or stripline structure together with the first air cavity 3 to optimize the transmission characteristics of the radio frequency signal.

[0069] In a possible implementation, Figure 3 As shown, there are two partitions 6 , which are arranged at intervals, and the two partitions 6 and the inner wall surface of the first main body section 51 form two first air cavities 3 .

[0070] Two partitions 6 are provided to enclose two first air cavities 3 with the inner wall of the first main body section 51. The structure of the two first air cavities 3 formed by the two partitions 6 can better achieve signal isolation. The two partitions 6 can guide the light to propagate in a specific direction in their respective air cavities, reduce the scattering and reflection of the light in different directions, so that the optical signal can be transmitted more directionally, and the accuracy of signal transmission is improved.

[0071] The sides of the two partitions 6 facing away from each other are connected to the inner wall surface of the first main body section 51 , and the two partitions 6 are arranged at intervals.

[0072] In this case, both first air cavities 3 are connected to the space between the two partitions 6. It should be noted that when the cross-sectional area of ​​one of the two first air cavities 3 is equal to the cross-sectional area of ​​the other air cavity, the quality and stability of equal power signal transmission can be improved, and signal distortion and bit error rate can be reduced.

[0073] The two air cavities with equal cross-sectional areas make the internal structure of the first main body section 51 more symmetrical and stable. When subjected to external mechanical stress, such as vibration, impact, etc., the symmetrical air cavity structure can disperse the stress more evenly and reduce the possibility of local deformation.

[0074] When the cross-sectional area of ​​one of the two first air cavities 3 is larger than the cross-sectional area of ​​the other first air cavity 3, the two first air cavities 3 can be used to transmit signals of different powers. The first air cavity 3 with a larger cross-sectional area can accommodate and transmit a signal with a larger power, while the first air cavity 3 with a smaller cross-sectional area can transmit a signal with a smaller power. In this way, the air cavity resources can be reasonably allocated according to the actual power requirements of the signal, thereby improving the signal transmission efficiency.

[0075] Signals of different frequencies have different propagation characteristics in the air. In general, higher frequency signals have shorter wavelengths and are more susceptible to restrictions and interference when propagating in a smaller space. Air cavities with larger cross-sectional areas can provide more suitable propagation space for signals with longer wavelengths and lower frequencies, reducing signal reflection and scattering. Air cavities with smaller cross-sectional areas can constrain and guide signals with shorter wavelengths and higher frequencies, making their propagation paths more stable, thereby improving the transmission characteristics of signals of different frequencies and, in turn, improving the overall signal transmission quality.

[0076] By reasonably setting the cross-sectional areas of the two air cavities, the internal space utilization of the first main body section 51 can be better optimized while satisfying functions such as signal transmission and heat dissipation.

[0077] Exemplarily, the ratio of the cross-sectional area of ​​one of the two first air cavities 3 to the cross-sectional area of ​​the other air cavity can be any one of 1:1, 1:2, 1:3, 1:4, 1:5, 2:3, 2:5, 2:7, 2:9, 3:4, 3:5, 3:7, 3:4, 3:8, 4:5, 4:7, 4:9.

[0078] It should be noted that the ratio of the cross-sectional area of ​​one of the two first air cavities 3 to the cross-sectional area of ​​the other air cavity may also be other ratios.

[0079] The distribution of the signal power in the two first air cavities 3 is the same as the ratio of the cross-sectional area of ​​one of the two first air cavities 3 to the cross-sectional area of ​​the other air cavity.

[0080] In a possible implementation, Figure 4 As shown, the number of the partition part 6 is one, and one partition part 6 and the inner wall surface of the first main body section 51 form two first air cavities 3 .

[0081] The two first air cavities 3 divided by one partition 6 can be used to simultaneously process signals of two different frequency bands. The signal in each air cavity is better confined within the respective cavity, thereby reducing signal crosstalk between adjacent air cavities.

[0082] In a possible implementation, Figure 5 As shown, there are three partitions 6 , which are arranged at intervals, and the three partitions 6 and the inner wall surface of the first main body section 51 form three first air cavities 3 .

[0083] The three first air cavities 3 divided by the three partitions 6 can be used to process signals of three different frequency bands simultaneously.

[0084] In a possible implementation manner, the number of the partitions 6 and the number of the first air chambers 3 can be set to corresponding numbers according to actual usage.

[0085] In one possible implementation, see Figure 2 and Figure 6 At least two main body air cavities 53 are provided in the cylindrical main body 5 and penetrate the first end 1 and the second end 2. Along the radial direction of the cylindrical main body 5, the at least two main body air cavities 53 are spaced apart from the at least two first air cavities 3, and the at least two main body air cavities 53 are spaced apart from the second air cavity 4.

[0086] The at least two main body air cavities 53 can achieve signal isolation.

[0087] At least two main air cavities 53 can buffer the mechanical force applied to the optical fiber from the outside. When the coupler 100 is subjected to external forces such as squeezing, stretching, bending, etc., the air or other filling materials in at least two main air cavities 53 can absorb and disperse part of the energy, reducing the direct impact of the external force on the air core and the optical fiber structure.

[0088] By providing at least two main body air chambers 53 , the weight of the coupler 100 can be reduced.

[0089] Exemplarily, the number of the main body air cavities 53 is set to be multiple, and the multiple main body air cavities 53 are equivalent to setting an additional isolation barrier between the air cavities for transmitting signals, further reducing mutual interference between signals.

[0090] In one possible implementation, see Figure 5 The cylindrical body 5 includes a first end 1 (see Figure 2 ) and the second end 2 (see Figure 2 ) of the plurality of connecting tubes 7, each connecting tube 7 has a main air cavity 53, and the plurality of connecting tubes 7 and the partition 6 enclose at least two first air cavities 3 and second air cavities 4 (see Figure 2 ).

[0091] The plurality of connecting tubes 7 are sequentially arranged along the circumferential direction and arranged along the radial direction, and the plurality of connecting tubes 7 enclose at least two first air cavities 3 and a second air cavity 4 .

[0092] The structure in which multiple connecting pipes 7 are sequentially arranged along the circumferential direction and arranged along the radial direction is relatively regular and repetitive, which is convenient for formulating a standardized production process. A mold or automated equipment can be used for batch production, thereby improving production efficiency and reducing production costs.

[0093] The manner in which a plurality of connecting tubes 7 enclose at least two first air cavities 3 and second air cavities 4 is easy to assemble. Each connecting tube 7 and partition 6 can be pre-made and then assembled in a certain order, which reduces the difficulty of assembly and further reduces the production time.

[0094] Exemplarily, the connecting tube 7 may be made of a glass tube.

[0095] In a second aspect, the present application also provides a fiber amplifier 200. Figure 7 The optical fiber amplifier 200 includes: a first coupler 01, an input source 02 and an output source 03. The first coupler 01 includes the coupler 100 provided by any one of the above embodiments. The input source 02 is connected to the first end 1 (see Figure 2 ) is connected. The output source 03 is connected to the second end 2 (see Figure 2 )connect.

[0096] The optical fiber amplifier 200 couples the signal generated by the input source 02 through the first coupler 01 and outputs the signal through the output source 03. Since the first coupler 01 includes the coupler 100 in the first aspect, the optical fiber amplifier 200 can process signals of multiple different frequency bands at the same time, and can also reduce the loss of the signal during the transmission process, thereby improving the coupling efficiency.

[0097] In a possible implementation, the input source 02 may be an optical signal, a wavelength division multiplexing signal, a fiber grating sensor signal, a Brillouin fiber sensor signal, or the like, or may be a device that generates the above signals, such as a semiconductor laser, a solid-state laser, a fiber laser, an optical modulator, an optical signal generator, an optical signal generator, etc.

[0098] In a possible implementation, the output source 03 may be an optical signal, a wavelength division multiplexing signal, a fiber grating sensor signal, a Brillouin fiber sensor signal, or the like, or may be a device that generates the above-mentioned signals, such as a semiconductor laser, a solid-state laser, a fiber laser, an optical modulator, an optical signal generator, an optical signal generator, etc.

[0099] In a possible implementation, Figure 7 and Figure 8 The first coupler 01 includes a first interface 011 and a second interface 012 located at the first end 1 . The first interface 011 is communicated with one first air cavity 3 , and the second interface 012 is communicated with another first air cavity 3 .

[0100] The first interface 011 and the second interface 012 are provided to connect with the input source 02. The first interface 011 and the second interface 012 are used to guide the input optical signal into the air cavity, thereby achieving specific path guidance and distribution of the optical signal.

[0101] The input source 02 includes a pump source 021 , which is connected to the first interface 011 . The input source 02 also includes a signal source 022 , which is connected to the second interface 012 .

[0102] By connecting the pump source 021 to the first interface 011 and the signal source 022 to the second interface 012, independent input of the pump light and the signal light is achieved, so that the pump light and the signal light can be accurately controlled and adjusted respectively.

[0103] Since the two first air cavities 3 are interconnected, the pump light and the signal light can be coupled in the interconnected area after being preliminarily processed in their respective air cavities, for example, optical signal amplification and wavelength conversion can be achieved through nonlinear optical effects, thereby enhancing the processing effect of the optical signal.

[0104] In one possible implementation, see Figure 7 and Figure 8 The first interface 011 is connected to the second interface 012 to form a connection interface 013. The optical fiber amplifier 200 further includes a first hollow core optical fiber 04, one end of which is connected to the pump source 021, and the other end of which is connected to the first interface 011.

[0105] The first hollow-core optical fiber 04 connects the pump source 021 and the first interface 011. It can be understood that the first hollow-core optical fiber 04 is a transmission channel for the pump light. Compared with the traditional solid-core optical fiber, the hollow-core optical fiber has lower loss and higher transmission efficiency when transmitting the pump light, and can more effectively transmit the pump light generated by the pump source 021 to the first coupler 01, reducing the loss of light energy during the transmission process.

[0106] Meanwhile, the first hollow-core optical fiber 04 serves as a bridge connecting the pump source 021 and the first coupler 01 . Its good optical performance and compatibility with the components at both ends help to enhance the coupling effect of the pump light between the pump source 021 and the first coupler 01 .

[0107] In a possible implementation, the diameter of the first hollow-core optical fiber 04 is greater than half of the maximum width of the communication interface 013. Figure 3 It is indicated by the dotted line H in the figure.

[0108] When the first hollow-core optical fiber 04 is connected to the first coupler 01, the diameter of the first hollow-core optical fiber 04 is greater than half of the maximum width of the connection interface 013, so that the first hollow-core optical fiber 04 has a larger fiber end face area for light coupling when connected to the first interface 011. Therefore, the first hollow-core optical fiber 04 can more fully cover the first interface 011, so that more pump light can enter the connection interface 013 from the hollow-core optical fiber and be transmitted to the first air cavity 3 of the first coupler 01, thereby improving the coupling efficiency of the pump light and reducing the light energy loss caused by incomplete coupling.

[0109] At the same time, since the diameter of the first hollow-core optical fiber 04 is relatively large, when connecting with the communication interface 013, the operation is relatively simpler and the requirement for connection accuracy is relatively low.

[0110] In a possible implementation, the diameter of the first hollow core optical fiber 04 is smaller than the radius of the coupler 100. The radius of the coupler 100 is Figure 3 It is indicated by a dotted line R in the figure.

[0111] The diameter of the first hollow core fiber 04 is smaller than the radius of the coupler 100, so that the area of ​​the end face of the first coupler 01 occupied by the first hollow core fiber 04 when connected to the first coupler 01 can be reduced, saving space for connecting the first coupler 01 to other devices.

[0112] Furthermore, the diameter of the first hollow-core optical fiber 04 is smaller than the radius of the coupler 100 , which can make the optical fiber wiring more flexible and the layout of the optical fiber amplifier 200 more compact.

[0113] In one possible implementation, see Figure 3 and Figure 8 The area of ​​the first interface 011 is equal to the area of ​​the second interface 012 .

[0114] When optical signals from the pump source 021 and the signal source 022 enter the first coupler 01 through the first interface 011 and the second interface 012 respectively, equal interface areas help to achieve uniform distribution of optical energy.

[0115] At the same time, after the optical signal enters the first coupler 01 through the first interface 011 and the second interface 012 , it is easier to form a symmetrical light field distribution in the two air cavities and in the subsequent optical signal processing process.

[0116] Furthermore, when the areas of the first interface 011 and the second interface 012 are equal, the light reflection and scattering caused by the change of the interface area can be reduced due to the consistency of the optical boundary conditions during the process of the optical signal entering the first coupler 01 from the outside and transmitting inside the coupler 100. Light reflection and scattering will lead to the loss of light energy and the increase of noise of the optical signal, and the equal interface area can reduce the probability of this situation, thereby improving the transmission efficiency and quality of the optical signal and reducing the loss and noise of the optical signal during the transmission process.

[0117] The optical fiber amplifier 200 further includes a signal optical fiber 05 , one end of which is connected to the signal source 022 , and the other end of which is connected to the second interface 012 .

[0118] One end of the signal optical fiber 05 is connected to the signal source 022, and the other end is connected to the second interface 012. Its main function is to serve as a transmission channel for the signal light from the signal source 022 to the first coupler 01. It can effectively transmit the signal light generated by the signal source 022 to the first coupler 01, so that the signal light can smoothly enter the optical fiber amplifier 200 system for subsequent processing, such as light amplification, wavelength conversion, etc. During the transmission process, the signal optical fiber 05 can better keep the wavelength, polarization state, mode and other characteristics of the signal light unchanged.

[0119] Exemplarily, the signal optical fiber 05 may use a hollow core optical fiber or a solid core optical fiber.

[0120] It should be noted that when the area of ​​the first interface 011 is equal to the area of ​​the second interface 012 and the radius of the signal fiber 05 is the same as that of the first hollow core fiber 04 , the diameter of the signal fiber 05 is greater than half of the maximum width of the communication interface 013 and less than the radius of the coupler 100 .

[0121] The diameter of the signal optical fiber 05 is greater than half of the maximum width of the communication interface 013. The maximum width of the communication interface 013 is Figure 3 It is indicated by the dotted line H in the figure.

[0122] When the signal optical fiber 05 is connected to the first coupler 01, the diameter of the signal optical fiber 05 is greater than half of the maximum width of the communication interface 013, so that when the signal optical fiber 05 is connected to the second interface 012, a larger optical fiber end face area can be used for light coupling. Therefore, the signal optical fiber 05 can more fully cover the second interface 012, so that more pump light can enter the second interface 012 from the hollow-core optical fiber and be transmitted to the second air cavity 4 of the first coupler 01, thereby improving the coupling efficiency of the pump light and reducing the optical energy loss caused by incomplete coupling.

[0123] At the same time, since the diameter of the signal optical fiber 05 is relatively large, when connecting with the communication interface 013, the operation is relatively simpler and the requirement for connection accuracy is relatively low.

[0124] In a possible implementation, the diameter of the signal optical fiber 05 is smaller than the radius of the coupler 100. Figure 3 It is indicated by a dotted line R in the figure.

[0125] The diameter of the signal optical fiber 05 is smaller than the radius of the coupler 100 , so that the area of ​​the end face of the first coupler 01 occupied by the signal optical fiber 05 when connected to the first coupler 01 can be reduced, saving space for the first coupler 01 to connect to other devices.

[0126] Furthermore, the diameter of the signal optical fiber 05 is smaller than the radius of the coupler 100 , which can make the optical fiber wiring more flexible and the layout of the optical fiber amplifier 200 more compact.

[0127] The signal optical fiber 05 has the same radius as the first hollow-core optical fiber 04. The same radius enables the signal optical fiber 05 and the first hollow-core optical fiber 04 to have similar optical boundary conditions and geometric structures when connected to their respective corresponding interfaces (the second interface 012 and the first interface 011). This is conducive to achieving a more consistent coupling effect during the optical coupling process, reducing the difference in coupling efficiency caused by different optical fiber radii, and allowing the signal light and the pump light to enter the first coupler 01 with a more similar coupling efficiency, thereby improving the stability and consistency of the optical coupling efficiency of the entire system.

[0128] In a possible implementation, Figure 7 The output source 03 provided in the present application includes an active optical fiber.

[0129] The active optical fiber is the core component of the optical fiber amplifier 200 for achieving optical amplification. Exemplarily, the active optical fiber is doped with at least one of the following active particles: erbium, ytterbium, and neodymium. When the coupled signal light is injected into the active optical fiber, the active particles absorb the energy of the pump light and transition to a high energy level. The particles at the high energy level transfer energy to the signal light through the stimulated radiation process, thereby amplifying the signal light. This optical amplification effect can effectively compensate for the attenuation of the optical signal during optical fiber transmission, extend the transmission distance of the optical signal, and improve the transmission capacity and reliability of the optical communication system.

[0130] In a possible implementation, Figure 7 and Fig. 9 The optical fiber amplifier 200 provided in the present application comprises a second hollow core optical fiber 06, one end of the second hollow core optical fiber 06 is connected to the first coupler 01, and the other end is connected to the active optical fiber.

[0131] The diameter of the second hollow core optical fiber 06 is the same as the diameter of the coupler 100. It should be noted that the diameter of the second hollow core optical fiber 06 is approximately the same as the diameter of the coupler 100 and also falls within this range.

[0132] The diameter of the second hollow-core optical fiber 06 is the same as the diameter of the coupler 100, so that when the second hollow-core optical fiber 06 is connected to the coupler 100, the end face of the second hollow-core optical fiber 06 can be better matched with the end face of the coupler 100, thereby increasing the area of ​​optical coupling, and reducing energy loss when the optical signal enters the second hollow-core optical fiber 06 from the coupler 100, thereby improving optical coupling efficiency and reducing optical energy loss caused by incomplete coupling.

[0133] In a possible implementation, Fig.10 The output source 03 includes a first output source 031 and a second output source 032 which are arranged in series; the first output source 031 is connected to the second end 2 of the coupler 100 in the first coupler 01;

[0134] The first output source 031 and the second output source 032 arranged in series can perform multi-stage processing after the optical signal is output from the first coupler 01. The first output source 031 can perform preliminary processing on the optical signal output from the first coupler 01, such as optical filtering, optical modulation, optical amplification, etc., and then transmit the processed optical signal to the second output source 032 for further processing or optimization, thereby realizing more complex optical signal processing functions and meeting the diverse requirements of different application scenarios for optical signals.

[0135] In the process of optical signal processing, noise and interference are important factors affecting signal quality. The first output source 031 and the second output source 032 connected in series can suppress and process noise and interference at different links. The first output source 031 can remove part of the noise and interference by filtering and other means, and the second output source 032 can further detect and process the optical signal processed by the first output source 031 to remove the remaining noise and interference, thereby effectively reducing the noise and interference in the optical signal and improving the signal-to-noise ratio and purity of the optical signal.

[0136] The optical fiber amplifier 200 further includes a second coupler 07, which includes the coupler 100 provided by any one of the embodiments of the first aspect; the second coupler 07 further includes a third interface 071 and a fourth interface 072 located at the first end 1 of the coupler 100. The second end 2 of the coupler 100 in the second coupler 07 is connected to the pump source 021, the third interface 071 is connected to the first interface 011; and the fourth interface 072 is connected to the second output source 032.

[0137] The second coupler 07 can distribute the pump light. After the pump light generated by the pump source 021 enters the second coupler 07, a part of it can be guided to the first coupler 01 through a specific path to provide energy for the amplification of the optical signal in the first coupler 01; the other part of the pump light can enter the second output source 032 through the fourth interface 072, and may be used to further process or enhance the optical signal processed by the first coupler 01 in the second output source 032. Thereby, the reasonable distribution of the pump light in different optical paths is realized, the utilization efficiency of the pump light is improved, the pump light can play a role in multiple links, and the entire optical amplification process is improved.

[0138] In one possible implementation, see Fig.10The optical fiber amplifier 200 further includes a third coupler 08. The third coupler 08 includes the coupler 100 provided by any one of the embodiments of the first aspect, and the third coupler 08 further includes a fifth interface 081 and a sixth interface 082 located at the first end 1 of the coupler 100, and the third coupler 08 is located between the first output source 031 and the second output source 032. The sixth interface 082 is connected to the first output source 031. The fifth interface 081 is connected to the fourth interface 072. The second end 2 of the coupler 100 in the third coupler 08 is connected to the second output source 032.

[0139] The third coupler 08 is a key component for transmitting optical signals between the first output source 031 and the second output source 032. The optical signal of the first output source 031 can enter the third coupler 08 through the sixth interface 082. The fifth interface 081 is connected to the fourth interface 072, and a portion of the pump light can enter the third coupler 08 through the fourth interface 072, thereby performing a second coupling at the third coupler 08.

[0140] In the first coupler 01, the pump light may have preliminarily amplified the signal light, and in the second coupling at the third coupler 08, the newly injected pump light can further replenish energy and continue to enhance the intensity of the optical signal, thereby achieving a higher optical amplification factor, better compensating for the attenuation of the optical signal during transmission, and extending the transmittable distance of the optical signal.

[0141] It should be noted that in the present application, when there is a connection between the optical fiber and the coupler 100, the optical signal can enter the coupler 100 from the optical fiber, or enter the optical fiber from the coupler 100. That is, the propagation direction of the optical signal is not limited by the structure of the coupler 100 of the present application, and the propagation direction of the optical signal is related to the position of the input source 02 and the output source 03.

[0142] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A coupler, characterized in that: The coupler comprises: The first end and the second end are arranged opposite to each other, and the coupler is provided with at least two first air cavities penetrating the first end and a second air cavity penetrating the second end; the at least two first air cavities are communicated with the second air cavity.

2. The coupler according to claim 1, characterized in that The coupler comprises: The cylindrical main body portion includes a first main body section and a second main body section; The partition is located in the first main body section and connected to the first main body section. The partition and the first main body section enclose the at least two first air cavities. The second air cavity is located in the second main body section.

3. The coupler according to claim 2, characterized in that: There are two partitions, which are arranged at intervals, and the two partitions and the inner wall surface of the first main body segment form two first air cavities.

4. The coupler according to claim 3, characterized in that: The two first air cavities are both connected to the space between the two partitions; and the cross-sectional area of ​​one of the two first air cavities is greater than or equal to the cross-sectional area of ​​the other air cavity.

5. The coupler according to claim 2, characterized in that: At least two main air cavities are arranged in the cylindrical main body and penetrate the first end and the second end; along the radial direction of the cylindrical main body, the at least two main air cavities are spaced apart from the at least two first air cavities, and the at least two main air cavities are spaced apart from the second air cavity.

6. The coupler according to claim 5, characterized in that The cylindrical main body comprises: A plurality of connecting tubes are passed through the first end and the second end, one of the connecting tubes is provided with the main body air cavity, and the plurality of connecting tubes and the partition part enclose the at least two first air cavities and the second air cavity.

7. An optical fiber amplifier, characterized in that: include: A first coupler, comprising the coupler according to any one of claims 1 to 6; an input source connected to a first end of the coupler in the first coupler; An output source is connected to the second end of the coupler in the first coupler.

8. The optical fiber amplifier according to claim 7, characterized in that: The first coupler includes a first interface and a second interface located at the first end; the first interface is connected to one first air cavity, and the second interface is connected to another first air cavity; The input source includes a pump source, and the pump source is connected to the first interface; The input source also includes a signal source, and the signal source is connected to the second interface.

9. The optical fiber amplifier according to claim 8, characterized in that: The first interface is connected to the second interface to form a connected interface; The optical fiber amplifier further comprises a first hollow core optical fiber, one end of the first hollow core optical fiber is connected to the pump source, and the other end is connected to the first interface; The diameter of the first hollow-core optical fiber is greater than half of the maximum width of the communication interface and smaller than the radius of the coupler.

10. The optical fiber amplifier according to claim 9, characterized in that: The area of ​​the first interface is equal to the area of ​​the second interface, and the optical fiber amplifier further comprises: A signal optical fiber, one end of which is connected to the signal source, and the other end of which is connected to the second interface; the signal optical fiber has the same radius as the first hollow-core optical fiber.

11. The optical fiber amplifier according to claim 8, characterized in that: The output source comprises a first output source and a second output source arranged in series; the first output source is connected to the second end of the coupler in the first coupler; The optical fiber amplifier also includes a second coupler, and the second coupler includes the coupler according to any one of claims 1 to 6; the second coupler also includes a third interface and a fourth interface located at the first end of the coupler; the second end of the coupler in the second coupler is connected to the pump source, and the third interface is connected to the first interface; the fourth interface is connected to the second output source.

12. The optical fiber amplifier according to claim 11, characterized in that: The optical fiber amplifier further comprises: A third coupler, the third coupler comprises the coupler according to any one of claims 1 to 6, the third coupler also comprises a fifth interface and a sixth interface located at the first end of the coupler, the third coupler is located between the first output source and the second output source; the sixth interface is connected to the first output source; the fifth interface is connected to the fourth interface; the second end of the coupler in the third coupler is connected to the second output source.

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