Optical fiber connector, optical fiber adapter, optical fiber connection assembly, optical backboard and system

Abstract

The invention provides an optical fiber connector, an optical fiber adapter, an optical fiber connection assembly, an optical backboard and a system, which are used for improving the detection precision of link information of an optical link by a detection device. By introducing optical elements for transmitting data signals and detection signals with different reflectivity into the optical fiber connector and / or the optical fiber adapter, the optical fiber connection assembly transmits the data signals with lower reflectivity and transmits the detection signals with higher reflectivity, so that the signal quality of the data signals is ensured, and the detection accuracy is improved. And the intensity of the detection signal reflected by the optical fiber connection assembly can be increased, so that the detection precision of the detection device on the optical link can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, in particular to a fiber connector, a fiber adapter, a fiber connection assembly, a fiber backboard and a system. BACKGROUND

[0002] With the development of optical fiber communication technology, optical network systems such as passive optical networks (PON) have been widely deployed, and the security, acceptance detection and routine maintenance of optical links in optical networks are also increasing. In order to meet the maintenance requirements of optical links, more and more optical networks have added detection devices such as optical time domain reflectometers (OTDR). OTDR sends detection signals to the optical link to be detected and detects the backscattering signals and reflected signals in the optical link, determines the reflectivity at each point in the optical link (such as the loss distribution curve of the optical link), and further determines the link information of the optical link, such as determining the length and transmission attenuation of the optical fiber, the connection quality and defect position of the optical fiber connector, and the identification and positioning.

[0003] However, the detection accuracy of the OTDR is currently low, and improving the detection accuracy of the OTDR has a positive significance for improving the reliability and stability of the optical network system. SUMMARY

[0004] The present application provides a fiber connector, a fiber adapter, a fiber connection assembly, a fiber backboard and a system for improving the detection accuracy of the OTDR.

[0005] In a first aspect, the present application provides a fiber connector, the fiber connector comprising a fiber ferrule and a housing for wrapping the fiber ferrule; the fiber ferrule comprises a ferrule base and a fiber fixed in the ferrule base, the fiber being used for detachable connection to an optical link to transmit optical signals in the optical link, the optical signals in the optical link comprising data signals of different wavelengths and first detection signals, wherein the data signals are used to transmit information along the optical link, and the first detection signals are used to detect the reflectivity at each point in the optical link; the fiber ferrule further comprises an optical element located in the optical path of the fiber, the optical element being used to respectively transmit the data signals and the first detection signals, but the reflectivity of the optical element to the first detection signals is greater than the reflectivity of the optical element to the data signals.

[0006] The reflectivity of the optical element to the first detection signal is greater than the reflectivity of the optical element to the data signal, which is conducive to increasing the signal strength of the first detection signal reflected by the optical element in the case that the optical element transmits the data signal at a lower reflectivity to ensure the signal quality of the data signal, thereby facilitating the detection device (e.g., OTDR) to improve the accuracy of the detection result of the optical link based on the first detection signal.

[0007] As introduced above, the detection signal can be used to detect the reflectivity at each position in the optical link in the time domain. The detection signal can be input into the optical link by a detection device, which is configured to detect the change of the signal strength of the reflected detection signal with the receiving time and determine the reflectivity at each position in the optical link according to the detection result, and further determine the link information of the optical link. For example, the detection device can determine the position of reflection in the optical link according to the receiving time (referred to as receiving time for short) of the reflected detection signal, and determine the reflectivity of the position to the detection signal according to the signal strength of the reflected detection signal.

[0008] By increasing the signal strength of the first detection signal reflected by the optical element, the detection device can more accurately determine the first detection signal reflected by the optical element from the first detection signals at different receiving times, which is conducive to not only improving the detection accuracy of the detection device to the reflectivity of the fiber connector, but also more accurately determining the signal strength of the first detection signal reflected by the position near the fiber connector, thereby improving the detection accuracy of the reflectivity, and further improving the accuracy of the link information. In addition, since the position of the fiber connector in the optical link is generally easy to measure, the receiving time of the first detection signal reflected by each position in the optical link can be more accurately determined according to the mapping relationship between the position of the fiber connector in the optical link and the receiving time of the first detection signal reflected by the fiber connector, thereby more accurately determining the signal strength of the first detection signal reflected by each position in the optical link, improving the detection accuracy of the detection device to the reflectivity of each position in the optical link, and further facilitating the detection device to obtain more accurate link information according to the reflectivity of each position in the optical link.

[0009] The application does not limit the specific content of the link information. Optionally, the link information can include at least one of the length of the optical fiber in the optical link, the transmission attenuation of the optical fiber, the connection quality of the fiber connector, and the defect position in the optical link.

[0010] The present application does not limit the number of optical fibers in the ferrule base. When the ferrule base includes a plurality of optical fibers, the optical fiber can be one of the optical fibers in the ferrule base. Alternatively, when the ferrule base includes a plurality of optical fibers, the optical fiber can be any one of at least two optical fibers in the ferrule base, which can be all or a part of the optical fibers in the ferrule base. Correspondingly, the optical element is mounted on the optical path of the at least two optical fibers, and the optical elements mounted on the optical paths of the different two optical fibers can be the same optical element or two independent optical elements.

[0011] Optionally, the optical element includes a negative filter film, the reflectivity of the negative filter film to the optical signal of the target wavelength range is greater than the reflectivity of the negative filter film to the optical signal of other wavelength ranges except the target wavelength range, and the wavelength of the first detection signal belongs to the target wavelength range, and the wavelength of the data signal belongs to the other wavelength ranges.

[0012] The negative filter film is used to transmit the data signal and the first detection signal with different reflectivities. The negative filter film can be replaced by other types of optical elements, such as fiber gratings or fiber waveguides or common filter films.

[0013] Common filter films are generally used to selectively transmit optical signals of a certain wavelength range (referred to as the central wavelength range of the common filter film), while negative filter films are generally used to selectively filter out optical signals of a certain wavelength range (referred to as the central wavelength range of the negative filter film). That is, unlike common filter films that are used to transmit optical signals of the central wavelength range with a lower reflectivity, negative filter films are used to transmit optical signals of the central wavelength range with a higher reflectivity. Therefore, the transmittance curve of the common filter film is generally convex, while the transmittance curve of the negative filter film is concave. By preparing the negative filter film to have a central wavelength range including the wavelength of the first detection signal and reducing the width of the central wavelength range, it is beneficial to increase the wavelength range of the data signal transmitted by the negative filter film with a lower reflectivity, thereby facilitating the improvement of the bandwidth of the optical fiber.

[0014] Compared with fiber gratings and fiber waveguides, negative filter films have a smaller volume, thereby facilitating the reduction of the size of the optical fiber connector, and thereby facilitating the miniaturization of the optical network equipment.

[0015] The other wavelength ranges can include a part or all of the wavelengths except the target wavelength range. Alternatively, the other wavelength ranges and the target wavelength range belong to a continuous wavelength range (referred to as an effective wavelength range), and the other wavelength ranges can include a part or all of the wavelengths in the effective wavelength range except the target wavelength range. For example, the effective wavelength range is 1200nm-1600nm, or 1200nm-1700nm.

[0016] Optionally, the data signal is all optical signals in the optical link for transmitting or carrying information.

[0017] Optionally, the other wavelength range is divided into at least two sub-wavelength ranges by the target wavelength range. Alternatively, the other wavelength range can include at least two sub-wavelength ranges, and the target wavelength range is located between different sub-wavelength ranges.

[0018] In this way, the wavelength of the first detection signal is closer to the wavelength of the data signal, or in other words, more reflects the average value of the wavelength of the data signal. Since the optical elements or defects in the optical link generally have the same or similar reflectivity for optical signals with close wavelengths, the detection result of the reflectivity obtained by the detection device based on the first detection signal more accurately reflects the reflection of the data signal by the optical link, thereby improving the reliability and stability of the optical link for transmitting the data signal.

[0019] In an example, the target wavelength range can be a continuous wavelength range, and the target wavelength range is located between two adjacent sub-wavelength ranges in the other wavelength range. For example, the target wavelength range is 1560nm-1580nm, and the other wavelength range includes wavelengths less than 1560nm and wavelengths greater than 1580nm.

[0020] In another example, the target wavelength range can include at least two sub-wavelength ranges, and the sub-wavelength ranges in the target wavelength range and the sub-wavelength ranges in the other wavelength range are alternately distributed. For example, the target wavelength range is 1560nm-1565nm and 1575nm-1580nm, and the other wavelength range includes wavelengths less than 1560nm, wavelengths between 1565nm and 1575nm, and wavelengths greater than 1580nm.

[0021] Optionally, the width of the target wavelength range is not more than 20nm, or not more than 15nm, or not more than 10nm, or not more than 5nm. In this way, it is not only beneficial to save the wavelength resources of the optical link and improve the bandwidth of the optical link, but also beneficial to improve the accuracy of the detection result based on the first detection signal.

[0022] Optionally, the width of the other wavelength range is greater than the width of the target wavelength range. For example, the ratio between the width of the other wavelength range and the width of the target wavelength range is not less than 100, or not less than 150, or not less than 200, or not less than 300, or not less than 400. In this way, it is beneficial to reduce the wavelength range occupied by the first detection signal, save the wavelength resources of the optical link, increase the wavelength range of the data signal, and improve the bandwidth of the optical link.

[0023] Optionally, a difference (i.e. r1-r2) between the reflectivity (denoted as r1) of the negative filter film to the light signal in the target wavelength range and the reflectivity (denoted as r2) of the negative filter film to the light signal in the other wavelength range is greater than a first threshold and less than a second threshold. Assuming that r2 is very small and can be ignored, r1 can be greater than the first threshold and less than the second threshold. The first threshold can be 1%, 5%, 10%, etc., and the second threshold can be 70%, 75%, 80%, 85%, 90%, etc. By limiting r1 to be greater than the first threshold, it is beneficial to avoid the situation that r1 is too small, which leads to the detection device having a low recognition accuracy of the first detection signal reflected by the optical element, and thus reduces the optimization effect on the accuracy of the link information. By limiting r1 to be less than the second threshold, it is beneficial to avoid the situation that r1 is too large, which leads to the first detection signal having a small transmission distance in the optical link, and thus reduces the dynamic range of the detection device.

[0024] Optionally, the optical element is coupled to an end face of the optical fiber, or the optical element is located inside the optical fiber. In this way, it is beneficial to flexibly install the optical element in an existing optical fiber connector.

[0025] Optionally, the negative filter film is coated on an end face of the optical fiber, the end face is exposed on a surface of the ferrule base, and the end face faces another optical fiber connector that is matched and connected with the optical fiber connector.

[0026] Optionally, the optical fiber has at least one group of sections inside the ferrule base, and the negative filter film can be coated on at least one section. Alternatively, the optical fiber includes discontinuous at least two fiber segments inside the ferrule base, and the section of the optical fiber refers to an end face of a fiber segment that faces an adjacent fiber segment, and a group of sections includes two adjacent sections on different fiber segments.

[0027] By coating the negative filter film on the end face or section of the optical fiber, it is beneficial to reduce the space occupied by the optical element in the optical fiber connector, and thus reduce the size of the optical fiber connector.

[0028] Optionally, the optical element further includes a light-transmitting element, the light-transmitting element is used to transmit the light signal in the optical link, and the negative filter film is coated on a surface of the light-transmitting element. The light-transmitting element can be a carrier for preparing the negative filter film, and by installing the light-transmitting element coated with the negative filter film in the optical fiber ferrule, it is beneficial to ensure the performance of the negative filter film.

[0029] The light-transmitting element can be coupled to the end face or section of the optical fiber. Compared with introducing a grating or a waveguide in the optical fiber connector, by coupling the light-transmitting element coated with the negative filter film to the end face or section of the optical fiber, it is beneficial to reduce the modification to the components in the existing optical network, and reduce the modification cost.

[0030] The "coupling" or coupling of the light-transmitting element end face or section means that the light signal can be transmitted between them, for example, the light signal in the optical link received from the other optical connector connected can be incident on the end face or section after being emitted from the light-transmitting element, and the light signal in the optical link sent to the other optical connector connected can be incident on the light-transmitting element after being emitted from the end face or section. The application does not limit the implementation of the lens coupled to the end face or section of the optical fiber, and the lens can be fixed on the end face or section, or on the optical fiber ferrule. The application does not limit the implementation of "fixed", for example, the fixing can be achieved by pasting or buckling.

[0031] Optionally, the light-transmitting element can also have the function of changing the beam shape of the light signal, for example, converging or collimating the light signal to reduce the loss of the light signal in the first optical path. The light-transmitting element can be a lens.

[0032] Optionally, the surface of the light-transmitting element is also coated with an anti-reflection film. In this way, it is beneficial to reduce the loss of the light signal in the optical link on the optical element, improve the signal quality of the data signal and the transmission distance of the first detection signal. The anti-reflection film and the negative filter film are coated on different surfaces or different surface regions of the light-transmitting element.

[0033] Optionally, the light signal in the optical link also includes a second detection signal, and the second detection signal is used to detect the reflectivity of the optical link. The wavelength of the second detection signal is different from the wavelength of the first detection signal, and the wavelength of the second detection signal belongs to the other wavelength range. In this way, it is beneficial to reduce the signal intensity of the second detection signal reflected by the optical element, not only to improve the length of the optical link that can be detected by the detection signal, but also to improve the accuracy of the detection device in identifying the detection signal reflected by the optical element by analyzing the reflectivity of the optical link to different wavelength detection signals, thereby improving the accuracy of the detection result of the optical link based on the first detection signal and the second detection signal. The wavelength of the second detection signal and the wavelength of the data signal can be the same or different.

[0034] Optionally, the first detection signal and / or the second detection signal is sent by an optical time domain reflectometer (OTDR) to the optical link.

[0035] The negative filter film generally has a low expansion coefficient or low linear strain sensitivity. In order to ensure the performance of the negative filter film, the material of the light-transmitting element and / or the optical fiber can be a material with a low expansion coefficient or low linear strain sensitivity. In order to avoid deformation of the optical element due to extrusion of the fiber ferrule, the material of the fiber ferrule can be selected to be a material with a low expansion coefficient. The material with a low expansion coefficient can refer to a material with a thermal expansion coefficient of not more than 15 ppm / degree Celsius.

[0036] The application does not limit the direct matching connection of the optical fiber connector and the other optical fiber connector. Alternatively, the optical fiber connector is used for matching connection with the other optical fiber connector through an optical fiber adapter.

[0037] In a second aspect, the application provides an optical fiber adapter, the optical fiber adapter has a connecting through hole, the connecting through hole is used for pluggably accommodating or inserting optical fiber ferrules of at least two optical fiber connectors, so that optical fibers in different optical fiber ferrules transmit optical signals in a same optical link, the optical signals in the optical link include data signals with different wavelengths and a first detection signal, wherein the data signals are used for transmitting information along the optical link, and the first detection signal is used for detecting reflectivity at each position in the optical link; an optical element is arranged in the connecting through hole, the optical element is used for respectively transmitting the data signals and the first detection signal, but the reflectivity of the optical element to the first detection signal is greater than the reflectivity of the optical element to the data signals.

[0038] The reflectivity of the optical element to the first detection signal is greater than the reflectivity of the optical element to the data signals, which is beneficial to increasing the signal strength of the first detection signal reflected by the optical element in the case that the optical element transmits the data signals with a lower reflectivity to ensure the signal quality of the data signals, thereby being beneficial to improving the accuracy of the detection result of the optical link based on the first detection signal by a detection device (such as an OTDR).

[0039] As introduced above, the detection signal can be used for detecting the reflectivity at each position in the optical link in the time domain. The detection signal can be input into the optical link by a detection device, the detection device is used for detecting the change of the signal strength of the reflected detection signal with receiving time, and determining the reflectivity at each position in the optical link according to the detection result, and further determining the link information of the optical link. For example, the detection device can determine the position of reflection in the optical link according to the time (referred to as receiving time) of receiving the reflected detection signal, and determine the reflectivity of the position to the detection signal according to the signal strength of the reflected detection signal.

[0040] By increasing the signal strength of the first detection signal reflected by the optical element, the detection device can more accurately determine the first detection signal reflected by the optical element from the first detection signals received at different times. This not only helps to improve the detection accuracy of the reflectivity of the fiber optic adapter by the detection device, but also helps to more accurately determine the signal strength of the first detection signal reflected by the position near the fiber optic adapter, thereby improving the detection accuracy of the reflectivity thereof, and thus improving the accuracy of the link information. In addition, since the position of the fiber optic adapter in the optical link is generally easy to measure, the mapping relationship between the position of the fiber optic adapter in the optical link and the receiving time of the first detection signal reflected by the fiber optic adapter can be used to more accurately determine the receiving time of the first detection signal reflected by each position in the optical link, and thus more accurately determine the signal strength of the first detection signal reflected by each position in the optical link, improve the detection accuracy of the reflectivity of each position in the optical link by the detection device, and thus help the detection device to obtain more accurate link information according to the reflectivity of each position in the optical link.

[0041] Optionally, the optical element includes a light-transmitting element and a negative filter film coated on the surface of the light-transmitting element, the reflectivity of the negative filter film to light signals of a target wavelength range is greater than the reflectivity of the negative filter film to light signals of other wavelength ranges except the target wavelength range, and the wavelength of the first detection signal belongs to the target wavelength range, and the wavelength of the data signal belongs to the other wavelength ranges.

[0042] As introduced in the first aspect, the light-transmitting element coated with the negative filter film can be other types of optical elements, such as fiber gratings or fiber waveguides or light-transmitting elements coated with ordinary filter films. The beneficial effects of selecting the light-transmitting element coated with the negative filter film can be referred to the related content of the first aspect, which will not be repeated here.

[0043] The link information, the number of fibers in the ferrule base, the possible implementation and effects of the data signal and the other wavelength range can be respectively referred to the related introduction of the first aspect.

[0044] For example, when the ferrule base includes a plurality of optical fibers, the optical fibers of the at least two fiber connectors can be inserted into the connecting through holes to conduct a plurality of optical links. The present application does not limit that each optical link transmits the data signal and the first detection signal. When at least two optical links are used to transmit the data signal and the first detection signal, the optical link can refer to one of the at least two optical links or any one of the optical links. When the optical element is arranged on the optical path of each of the at least two optical links, the optical elements on the optical paths of different optical links can be the same optical element or two independent optical elements.

[0045] For example, the other wavelength range is optionally separated by the target wavelength range into at least two sub wavelength ranges. The target wavelength range optionally has a width of no more than 20 nm. The reflectivity of the negative filter film to the optical signal of the target wavelength range is optionally greater than 1% and less than 80% than the reflectivity of the negative filter film to the optical signal of the other wavelength range.

[0046] The light-transmitting element optionally has a function of changing the beam shape of the optical signal, such as converging or collimating the optical signal to reduce the loss of the optical signal in the first optical path. The light-transmitting element can be a lens.

[0047] The surface of the light-transmitting element is optionally coated with an anti-reflection film. This is advantageous to reduce the loss of the optical signal on the optical element in the optical link and improve the signal quality of the data signal and the transmission distance of the first detection signal. The anti-reflection film and the negative filter film are coated on different surfaces or different surface regions of the light-transmitting element.

[0048] The optical signal in the optical link optionally further includes a second detection signal for detecting the reflectivity at various positions in the optical link, but the wavelength of the second detection signal belongs to the other wavelength range. This is advantageous to reduce the signal intensity of the second detection signal reflected by the optical element, not only to improve the length of the optical link that can be detected by the detection signal, but also to enable the detection device to more accurately identify the detection signal reflected by the optical element by analyzing the reflectivity of the optical link to the detection signal of different wavelengths, thereby improving the accuracy of the detection result of the optical link based on the first detection signal and the second detection signal. The wavelength of the second detection signal and the wavelength of the data signal can be the same or different.

[0049] The first detection signal and / or the second detection signal are optionally sent by an optical time domain reflectometer (OTDR) to the optical link.

[0050] The negative filter film generally has a low expansion coefficient or low linear strain sensitivity. In order to ensure the performance of the negative filter film, the light-transmitting element can be made of a material with a low expansion coefficient or low linear strain sensitivity. In order to avoid deformation of the optical element due to the extrusion of the hole wall of the connecting through hole, the hole wall of the connecting through hole or the entire fiber optic adapter can be made of a material with a low expansion coefficient. The material with a low expansion coefficient can refer to a material with a thermal expansion coefficient of no more than 15 ppm / degree Celsius.

[0051] In a third aspect, the present application provides a fiber optic connection assembly including at least two fiber optic connectors for mating connection, and at least one of the at least two fiber optic connectors is as described in the first aspect or any possible implementation manner of the first aspect.

[0052] In a fourth aspect, the present application provides an optical fiber connection assembly, which comprises an optical fiber adapter and at least two optical fiber connectors for mating connection through the optical fiber adapter, and the optical fiber adapter is as described in the second aspect or any possible implementation manner of the second aspect, and / or at least one of the at least two optical fiber connectors is as described in the first aspect or any possible implementation manner of the first aspect.

[0053] In a fifth aspect, the present application provides an optical backboard, which comprises a board and one or more optical fibers fixed on the board, and at least one of the optical fibers is connected to an optical fiber connector as described in the first aspect or any possible implementation manner of the first aspect.

[0054] In a sixth aspect, the present application provides an optical network system, which comprises a sending end, a detection device and an optical link, wherein the optical link comprises an optical fiber connection assembly as described in the third aspect or the fourth aspect and a plurality of optical fibers for mating connection through the optical fiber connection assembly; the sending end is configured to send a data signal carrying information to the optical link; the detection device is configured to send a detection signal to the optical link; the optical link is configured to transmit the data signal and the detection signal; and the detection device is further configured to detect the detection signal reflected by the optical link and determine reflectivity of the optical link according to the detection result.

[0055] Optionally, the detection signal can comprise the first detection signal as described above. The optical fiber connection assembly is provided with the optical element as described above, and the optical element can transmit the first detection signal at a higher reflectivity and transmit the data signal at a lower reflectivity.

[0056] Optionally, the optical link can further comprise more optical fiber connection assemblies as described in the third aspect or the fourth aspect. For the purpose of distinction, the two optical fiber connection assemblies in the optical link are referred to as a first optical fiber connection assembly and a second optical fiber connection assembly.

[0057] Optionally, the two optical elements are configured to transmit the first detection signal with a higher reflectivity and transmit the data signal with a lower reflectivity. However, the two optical elements can have different reflectivities for the first detection signal. Since the signal strength of the detection signal decreases with the transmission distance, if the second fiber connection component is farther away from the detection device than the first fiber connection component, the first fiber connection component can have a lower reflectivity for the first detection signal than the second fiber connection component, which is beneficial to increase the signal strength of the first detection signal reaching the second fiber connection component, and thus increase the signal strength of the first detection signal reflected by the second fiber connection component, and improve the detection accuracy of the detection device for the first fiber connection component and the second fiber connection component, and thus improve the accuracy of the link information. In addition, reducing the reflectivity of the first fiber connection component for the first detection signal is beneficial to increase the transmission distance of the first detection signal in the optical link, and thus is beneficial to increase the length of the optical link that can be detected by the detection device.

[0058] The present application does not limit the content of the link information. For example, the link information can include length information and / or fault information. The length information can include the length of the entire optical link and / or the length of one or more components in the optical link. The fault information can include the location of a defect in the optical link. The defect can refer to a link region in the optical link that has a reflectivity for the optical signal exceeding a threshold due to a fault.

[0059] Optionally, the detection device can also pre-store reflectivity information, which can include the reflectivity of the first fiber connection component for the first detection signal and / or a parameter calculated based on the reflectivity. The detection device can determine the connection quality of the first fiber connection component based on the measured loss of the first detection signal at the first fiber connection component and the pre-stored reflectivity information.

[0060] Optionally, the detection signal can also include the second detection signal as described above. The optical element in the first fiber connection component can transmit the first detection signal with a higher reflectivity and transmit the second detection signal with a lower reflectivity, while the optical element in the second fiber connection component can transmit the first detection signal with a lower reflectivity and transmit the second detection signal with a higher reflectivity. In this way, it is not only beneficial to increase the signal strength of the detection signal reflected by the fiber connection component, but also beneficial to reduce the number of optical elements that the first detection signal and the second detection signal respectively pass through, and increase the transmission distance of the first detection signal and the second detection signal in the optical link, and thus beneficial to increase the dynamic range of the detection device.

[0061] The possible implementation manners and beneficial effects of the fiber optic connection assembly, the optical backplane and the system related to the fiber optic connector or the fiber optic adapter can be understood with reference to the related content of the first aspect or the second aspect, and will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 Schematic illustration of a possible structure of an optical network;

[0063] Figure 2 Schematic illustration of a transmittance curve of a negative filter film as a function of wavelength;

[0064] Figure 3 Schematic illustration of another transmittance curve of a negative filter film as a function of wavelength;

[0065] Figure 4 Schematic illustration of a cross-sectional view of two fiber optic connectors mated through an adapter;

[0066] Figure 5 Schematic illustration of another cross-sectional view of two fiber optic connectors mated through an adapter;

[0067] Figure 6-1 Schematic illustration of a cross-section of a negative filter element in the x-y plane;

[0068] Figure 6-2 Schematic illustration of a surface of a negative filter element in the y-z plane;

[0069] Figure 7 Schematic illustration of another cross-sectional view of two fiber optic connectors mated through an adapter;

[0070] Figure 8-1 Schematic illustration of another cross-section of a negative filter element in the x-y plane;

[0071] Figure 8-2 Schematic illustration of another cross-sectional view of two fiber optic connectors mated through an adapter;

[0072] Figure 9 , Figure 10-1 and Figure 10-2 Schematic illustration of another cross-sectional view of two fiber optic connectors mated through an adapter;

[0073] Figures 11-1 to 11-3 Schematic illustration of a cross-section of a fiber 1-1 and a lens 1-1 in the x-y plane;

[0074] Figure 11-4 Schematic illustration of a cross-sectional view of a fiber optic connection assembly with a negative filter element installed inside the fiber;

[0075] Figure 12-1 andFigure 12-2 The cross-sections of the first fiber optic ferrule in the xz plane are schematically shown respectively;

[0076] Figure 12-3 schematically shown Figure 12-2 The lens shown has a surface coated with a negative filter film.

[0077] Figure 13 This schematic diagram illustrates a local link in an optical network.

[0078] Figure 14-1 The diagram illustrates the loss distribution curve of optical link a obtained by the detection device.

[0079] Figure 14-2 The transmittance of fiber optic connector a-1 as a function of wavelength is schematically shown by solid lines, while the transmittance of fiber optic connector a-2 as a function of wavelength is schematically shown by dashed lines. Detailed Implementation

[0080] Optical network systems (or optical networks) are becoming increasingly widely used. An optical network can include a transmitter, a receiver, and an optical fiber link (or optical link). The transmitter sends optical signals carrying data (called data signals) to the optical fiber link, the optical fiber link transmits the data signals to the receiver, and the receiver receives the data signals.

[0081] Figure 1 The diagram schematically illustrates a possible structure of an optical network. For example... Figure 1 As shown, the optical network includes a service board 2, a backplane 1, and a switching board 3. The service board 2 is equipped with a circuit unit 4, which is connected to a fiber optic connector 6 on the backplane 1 via a fiber optic connector 5. The circuit unit 9 of the switching board 3 is connected to a fiber optic connector 7 on the backplane 1 via a fiber optic connector 8. Signal connections are established between fiber optic connectors 6 and 7 to enable signal transmission between the circuit unit 4 on the service board 2 and the circuit unit 9 on the switching board 3.

[0082] Circuit unit 4 and circuit unit 9 can serve as the data transmitter and receiver, respectively. For example, circuit unit 4 is used to transmit an optical signal carrying data (called a data signal). The data signal is transmitted sequentially to circuit unit 9 via the optical fiber on service board 2, optical fiber connector 5, optical fiber connector 6, optical fiber connector 8, optical fiber connector 7 and the optical fiber on switching board 3.

[0083] Alternatively, circuit unit 4 and circuit unit 9 can serve as the receiver and transmitter, respectively. Circuit unit 9 is used to transmit data signals, which are transmitted sequentially to circuit unit 4 via optical fibers on switching board 3, optical fiber connector 7, optical fiber connector 8, optical fiber connector 6, optical fiber connector 5, and optical fibers on service board 2.

[0084] Fiber optic connectors are reusable passive devices used to connect two or more optical fibers to form a continuous optical path. This application does not limit the type of fiber optic connector. For example, a fiber optic connector can be a single-fiber connector, such as a Ferrule Connector (FC), Lucent Connector (LC), or Square Connector (SC). Alternatively, a fiber optic connector can be a multi-fiber connector, such as a Mechanical Transfer (MT) interface or a Fiber Array (FA) interface. The MT interface is used to achieve mechanical mating transmission, and the ferrule has multiple cores (e.g., 2-96 cores).

[0085] This application refers to a set of matched fiber optic connectors as a fiber optic connection assembly. Figure 1 Taking an optical fiber link that includes two optical fiber connectors as an example, an optional optical fiber link may include more or fewer optical fiber connectors.

[0086] Figure 1 Taking the deployment of an optical network on a single host or rack as an example, this application does not limit the scale of the optical network. Optionally, the transmitting end and the receiving end can be deployed on different hosts or different racks.

[0087] This application does not limit the type of optical network. For example, an optical network may include any one or more combinations of PON, optical transport network (OTN), optical access network (OAN), metropolitan area network (MAN), synchronous digital hierarchy (SDH), Ethernet, or flexible Ethernet (FlexE) and wavelength division multiplexing (WDM) networks. Figure 1 The optical network shown is a PON example. The transmitting end and the receiving end can be an OLT and an optical network unit (ONU), or an ONU and an OLT, respectively. This application does not limit the access method of the optical access network. For example, the access method of the access network can be fiber to the home (FTTH) or direct connect (DC).

[0088] The present application does not limit the type of backplane, for example, the backplane can be an optical cross-connect (OXC) unit.

[0089] As optical networks are increasingly widely used in the field of communications, there are more and more security, acceptance testing and routine maintenance services for optical networks. Optical time domain reflectometer (OTDR) can play an important role in the detection, fault location and elimination of optical networks, and therefore, how to better use OTDR to improve the maintenance efficiency of optical networks has profound positive significance.

[0090] The present application does not limit the deployment of OTDR in the optical network system. For example, the OTDR can be deployed in the sending end introduced in the foregoing. In this way, the sending end not only sends data signals to the optical fiber, but also sends detection signals to the optical fiber. Alternatively, the OTDR can be deployed outside the sending end, or in other words, the OTDR and the sending end are independently deployed, and the data signal and the detection signal can be combined into the measured optical fiber outside the sending end.

[0091] In the process of detecting the optical fiber link (referred to as the measured optical fiber link) in the optical network using the OTDR, the OTDR can emit an optical signal (referred to as a detection signal) for detection to the measured optical fiber link. When the detection signal is transmitted through the measured optical fiber link, a backscattering signal can be formed due to the characteristics of the optical fiber and / or a reflection signal can be formed due to the events (connection, breakage, optical fiber tail end, etc.) of the optical fiber link. The OTDR can receive the backscattering signal or the reflection signal, and determine the link information of the measured optical link according to the received detection signal. For example, the OTDR can calculate and obtain a loss distribution curve along the length of the measured optical fiber link according to the intensity and arrival time of the received detection signal, and further determine the length of the optical fiber in the optical link and the transmission attenuation, the connection quality of the optical fiber connector in the optical link, and the identification and positioning of the defect area in the optical link, etc.

[0092] Since the position of the optical fiber connection assembly in the optical link is usually known, the detection device can use the position of the optical fiber connection assembly as a reference to improve the detection accuracy of the optical link. For example, after the detection device obtains the loss distribution curve, the loss distribution curve can be mapped to the actual optical link according to the position of the event curve corresponding to the optical fiber connection assembly in the loss distribution curve and the actual position of the optical fiber connection assembly in the optical link, to improve the accuracy of the link information.

[0093] However, in order to ensure the signal quality of the data signal, the quality of the optical link is constantly improved, and the loss of the signal on each element (including the fiber connection assembly) of the link is constantly reduced. When there is a defect on the optical link, the signal strength of the reflected signal generated by the defect is generally much greater than the signal strength of the reflected signal generated by the fiber connection assembly, resulting in low identification accuracy of the OTDR for the optical connection assembly, and it is difficult to improve the accuracy of the link information based on the fiber connection assembly.

[0094] In order to improve the detection accuracy of the OTDR for the optical link (or improve the accuracy of the link information determined by the OTDR), the present application provides a fiber connection assembly, which transmits data signals and detection signals with the same low reflectivity as the existing fiber connection assembly, and the reflectivity of the detection signal of the fiber connection assembly provided by the present application is greater than the reflectivity of the data signal during the transmission of the data signal and the detection signal. In order to facilitate distinction, the fiber connection assembly provided by the present application is referred to as a filter type fiber connection assembly hereinafter. The present application also proposes deploying at least one filter type fiber connection assembly in the optical link, which is beneficial on the one hand to enhance the signal strength of the detection signal reflected by at least one fiber connection assembly, thereby improving the detection accuracy of the corresponding fiber connection assembly by the detection device, and further improving the detection accuracy (such as improving the spatial resolution) of the optical link by the detection device, and on the other hand, it is beneficial to reduce the signal strength of the data signal reflected by the fiber connection assembly, thereby facilitating the reduction of the loss of the data signal in the optical link, and further improving the signal quality of the data signal and the reliability of the optical link.

[0095] The present application does not limit the implementation of the filter type fiber connection assembly. Since the ordinary filter film is used to select the light signal of a certain wavelength range, that is, the ordinary filter film is used to transmit the light signal of a single continuous wavelength range (i.e. the center wavelength of the ordinary filter film) with a low reflectivity, and transmit the light signal of other wavelength ranges with a high reflectivity. In order to ensure the bandwidth of the data signal transmitted by the optical link, the wavelength range of the data signal is generally much larger than the wavelength range of the detection signal. Therefore, the present application proposes that a fiber grating or a fiber waveguide or an optical filter can be assembled in the filter type fiber connection assembly, and the detection signal of a smaller wavelength range is transmitted with a high reflectivity by the grating or the waveguide or the optical filter, and the data signal of a larger wavelength range is transmitted with a low reflectivity.

[0096] Fiber grating is a kind of diffraction grating formed by axially periodic modulation of the refractive index of the fiber core through a certain method, and is a kind of passive filter device. Since the fiber grating has the advantages of small fusion loss, full compatibility with optical fiber, and can be embedded in intelligent materials, and its resonant wavelength is sensitive to changes in temperature, strain, refractive index, concentration and other external environments, it has been widely used in the fields of fiber laser, optical fiber communication and sensing. Optical filter is an instrument used for wavelength selection, which can select the required wavelength from a large number of wavelengths, and the light other than this wavelength will be rejected. It can be used for wavelength selection, noise filtering of optical amplifiers, gain equalization, optical multiplexing / demultiplexing.

[0097] However, the volume of the grating, waveguide and optical filter is generally large, which is not conducive to the miniaturization of the optical fiber connection assembly. Moreover, the modification cost of assembling the grating or waveguide in the existing optical network optical connection assembly is high, which increases the modification cost of the optical network.

[0098] It is found through research that the negative filter film can remove a certain waveband (referred to as high reflection waveband or central waveband or central wavelength range) from a certain spectrum. Figure 2 The transmittance of the negative filter film with respect to the wavelength is schematically shown in the curve. The negative filter film has high reflectivity to the light signal of the central waveband, so the central waveband has a lower transmittance in the curve shown by Figure 2 The negative filter film has low reflectivity to the light signal of the wavelength outside the central waveband (referred to as low reflection waveband), so the low reflection waveband has a higher transmittance in the curve shown by Figure 2 The curve of the negative filter film shown by Figure 2 is concave, so the negative filter film is also commonly referred to as a concave negative filter film.

[0099] Moreover, by changing the preparation process or parameters of the negative filter film, the central waveband and / or the difference between the high reflectivity and the low reflectivity (referred to as reflectivity difference) of the negative filter film can be adjusted. The adjustment of the central waveband includes adjustment of the starting position and / or the ending position of the central waveband.

[0100] Based on the above findings, it is proposed in the present application that by adjusting the preparation process or parameters of the negative filter film, the high reflection waveband of the negative filter film includes the wavelength of the detection signal but not the wavelength of the data signal, and the low reflection waveband of the negative filter film includes the wavelength of the data signal. The negative filter film is introduced into the optical fiber connection assembly to realize a filtering type optical fiber connection assembly, so as to realize transmission of the detection signal with a smaller wavelength range at a higher reflectivity and transmission of the data signal with a larger wavelength range at a lower reflectivity.

[0101] Adjusting the central wavelength range of the negative filter film and applying a normal filter film in the fiber connection assembly can increase the wavelength range of the data signal transmitted by the fiber connection assembly with low reflectivity, thereby increasing the bandwidth of the data signal transmitted by the fiber, and avoiding the introduction of a grating or waveguide with a large volume in the fiber connection assembly, thereby reducing the volume of the fiber connector. In addition, compared with introducing a grating or waveguide in the fiber connection assembly, introducing a negative filter film or a negative filter element in the fiber connection assembly can reduce the modification of components in the existing optical network and reduce the modification cost.

[0102] The present application does not limit the negative filter film to have high transmittance for all wavelengths except the central wavelength range. As long as the wavelength range of the low reflection band of the negative filter film is greater than the wavelength range of the high reflection band, it is beneficial for the fiber connection assembly to transmit the detection signal with a smaller wavelength range with high reflectivity and transmit the data signal with a larger wavelength range with low reflectivity.

[0103] Figure 3 Another curve showing the change of the transmittance of the negative filter film with wavelength is schematically shown. As shown in Figure 3 By adjusting the preparation process or parameters of the negative filter film, the wavelength range of the negative filter film can be reduced, and even the central wavelength range can be considered to include only one wavelength λ1. In this way, it is beneficial to further increase the wavelength range of the optical signal transmitted by the negative filter film with low reflectivity, thereby increasing the bandwidth of the optical link. Figure 3 The negative filter film corresponding to the curve is generally also called an extremely narrow negative filter film.

[0104] Figure 2 And Figure 3 The present application does not limit the high reflection wavelength range of the negative filter film to be a continuous wavelength range, nor does it limit the high reflection wavelength range to be located in the middle of the low reflection wavelength range, nor does it limit the width of the high reflection wavelength range and the low reflection wavelength range, nor does it limit the reflectivity corresponding to the low reflection wavelength range and the high reflection wavelength range.

[0105] The possible methods of introducing a negative filter film in the fiber connection assembly are described below.

[0106] In some examples, the fiber connection assembly can include two fiber connectors and an adapter. The fiber connectors can include fiber ferrules and housings for wrapping the fiber ferrules, and one or more optical fibers are fitted in the fiber ferrules. For the sake of distinction, one of the fiber connectors is referred to as a first fiber connector, the other fiber connector is referred to as a second fiber connector, the fiber ferrules in the first fiber connector and the second fiber connector are referred to as a first fiber ferrule and a second fiber ferrule respectively, the ferrule base and the optical fiber in the first fiber ferrule are referred to as a ferrule base 1-1 and an optical fiber 1-1 respectively, and the ferrule base and the optical fiber in the second fiber ferrule are referred to as a ferrule base 1-2 and an optical fiber 1-2 respectively. The two fiber connectors can be connected through the adapter, Figure 4 A cross-sectional view is schematically shown when the two fiber connectors are connected through the adapter. As Figure 4 shown, when the two fiber connectors are connected through the adapter, an optical path (referred to as an optical path 1) can be formed between the optical fiber 1-1 and the optical fiber 1-2

[0107] In order to realize the filtering type fiber connection assembly, it is proposed that an optical element coated with a negative filter film can be fitted in the connecting through hole of the adapter. For the sake of description, the optical element coated with the negative filter film is referred to as a negative filter element. The negative filter film on the negative filter element is located in the optical path 1, and the obtained filtering type connection assembly can refer to Figure 5 shown. Figure 5 The difference from Figure 4 is only that the negative filter element is newly added in the connecting through hole, and the negative filter element is located on the optical path 1. Therefore, in order to make the drawings simple, Figure 5 the labels of other elements except the newly added element (i.e. the negative filter element) are not shown, and the labels and introductions of other elements can be understood with reference to the related content of Figure 4 , which will not be described here in detail.

[0108] As Figure 5 shown, only the negative filter element needs to be newly added in the connecting through hole of the adapter, and the filtering type fiber connection assembly can be realized, which is conducive to reducing the difficulty of modifying the fiber connection assembly in the existing optical network to the filtering type fiber connection assembly, the network construction cost is low, and the reliability is high.

[0109] Figure 6-1 A cross section of the negative filter element in the x-y plane is schematically shown. As Figure 6-1 shown, the negative filter element includes a lens and a negative filter film on the surface of the lens. Figure 6-1Taking the negative filter film deposited on the surface of the lens facing the optical fiber 1-2 as an example, the negative filter film can optionally be deposited on the surface of the lens facing the optical fiber 1-1, or deposited on the surface of the negative filter element facing the optical fiber 1-1 and the surface facing the optical fiber 1-2, respectively.

[0110] For ease of description, this application refers to the surface area on the lens coated with a negative filter film as the target area. Figure 6-1 Taking the example that the entire surface of the lens facing the optical fiber 1-2 is coated with a negative filter film, the target area can optionally be a part of the surface, as long as the target area is located on the optical path 1. Figure 6-2 The surface of the negative filter element in the yz plane is schematically shown, as follows: Figure 6-2 As shown, the target area is a portion of one surface of the lens.

[0111] Figure 5 Taking the assembly position of the negative filter element in the connecting via such that optical path 1 is perpendicular to the negative filter film as an example, this application does not limit the angle between the negative filter film and optical path 1. Figure 7 As shown, the angle between optical path 1 and the negative filter film does not have to be 90 degrees. For example, the negative filter element can be assembled according to the center angle of the negative filter film, so that the optical signal in optical path 1 is incident on the negative filter film at the center angle or close to the center angle, ensuring the filtering effect of the negative filter film and achieving the required center band, reflectivity difference, and return loss.

[0112] Figure 7 and Figure 4 The only difference is that a negative filter element has been added to the connecting via, and this negative filter element is located on optical path 1. Therefore, for the sake of brevity in the attached diagram, Figure 7 The labels for components other than the newly added component (i.e., the negative filter component) are not shown. For the labels and descriptions of other components, please refer to [reference needed]. Figure 4 The relevant content will be understood in detail here, and will not be repeated.

[0113] This application does not limit the spacing between the end face of the optical fiber and the surface of the negative filter element. Figure 5 and Figure 7 Taking the distance between the end face of the optical fiber and the surface of the filter as an example, in some examples, the distance between the end face of the optical fiber and the surface of the filter can be 0, or in other words, the end face of the optical fiber can contact the surface of the filter.

[0114] To reduce beam loss in optical path 1, such as Figure 8-1 As shown, the negative filter element may also include an anti-reflection coating, and the anti-reflection coating is also located on optical path 1. For example... Figure 8-1 As shown, the surface of the lens of the negative filter element coated with the anti-reflection film is positioned opposite to the surface coated with the negative filter film. Figure 8-1Taking the antireflection film parallel to the negative filter film as an example, when their center angles are different, they do not have to be parallel in order to ensure their optical performance.

[0115] To reduce beam loss in optical path 1, such as Figure 8-2 As shown, the end faces of fiber 1-1 and fiber 1-2 can be coated with antireflection films respectively. Optionally, the end faces of fiber 1-1 or fiber 1-2 are coated with antireflection films.

[0116] Figure 8-2 and Figure 4 The only difference is that a negative filter element is added to the connecting via, and an anti-reflection coating is added to the fiber end face. Therefore, for the sake of brevity in the accompanying drawings, Figure 8-2 The labels for components other than the newly added component (i.e., the negative filter component) are not shown. For the labels and descriptions of other components, please refer to [reference needed]. Figure 4 The relevant content will be understood in detail here, and will not be repeated.

[0117] To optimize the optical signal mode or beam shape in optical path 1, such as Figure 9 As shown, lenses 1-1 and 1-2 can also be added to the optical fiber connector assembly. Lenses 1-1 and 1-2 are located on optical path 1 and are used to adjust the mode of the beam in optical path 1, such as adjusting the divergence angle, focusing or collimating it, so as to improve the coupling efficiency of the optical fiber to the optical signal in optical path 1, reduce the loss of the optical signal in the optical fiber connector assembly, and improve the signal quality of data signal and detection signal.

[0118] This application does not limit the shape of the lens. For example, the lens can be a conventional lens (C-lens) or a gradient-index lens (G-lens).

[0119] Figure 9 and Figure 4 The only difference is that a negative filter element and a lens have been added to the fiber optic connection assembly, and all of these new elements are located on optical path 1. Therefore, for the sake of brevity in the accompanying diagram, Figure 9 The labels for components other than the newly added components are not shown. For the labels and descriptions of other components, please refer to [reference needed]. Figure 4 The relevant content will be understood in detail here, and will not be repeated.

[0120] like Figure 9As shown, the lens 1-1 is embedded in the ferrule base 1-1 and contacts the end face of the optical fiber 1-1, and the lens 1-2 is embedded in the ferrule base 1-2 and contacts the end face of the optical fiber 1-2. The application does not limit the fixing mode of the lens in the ferrule, nor the positional relationship between the lens and the end face of the optical fiber, as long as the lens is coupled with the end face of the optical fiber or the end face of the optical fiber is located in the optical path 1.

[0121] In some examples, the end face of the optical fiber can be processed so that the end face of the optical fiber also has the function of the lens.

[0122] The foregoing takes the lens in the negative filter element as an example. The lens can be used to adjust the mode or beam shape of the light beam in the optical path 1, for example, the light beam in the optical path 1 can be converged or collimated, etc., to improve the coupling efficiency of the optical fiber to the optical signal in the optical connection assembly, reduce the loss of the optical signal in the optical fiber connection assembly, and improve the signal quality of the optical signal. The application does not limit the function of the optical element to have the function of the lens, as long as the optical element can transmit the optical signal. The application does not limit the shape of the optical element, for example, the two surfaces of the optical element located in the optical path 1 can be parallel or not parallel, for example, the surface of the optical element can be a plane or a curved surface.

[0123] In some examples, the negative filter element can include multiple negative filter films, or different negative filter films are located at different positions in the optical path 1, or the optical signal in the optical path 1 can pass through multiple negative filter films during transmission in the negative filter element. For example, the negative filter film shown in the figure can be replaced by Figure 8-1 The antireflection film shown is replaced by a negative filter film, and the optical signal will pass through the negative filter film, the lens and another negative filter film in sequence during transmission in the negative filter element. This is conducive to reducing the requirement for the reflectivity difference of a single negative filter film and reducing the difficulty of preparing the negative filter film.

[0124] The foregoing takes the optical element in the negative filter element as an example of a single optical element for transmitting an optical signal (or called light transmission). In some examples, the optical element can include multiple light-transmitting optical elements, and at least one optical element is coated with a negative filter film. For example, the negative filter film shown in the figure can be replaced by Figure 6-1 or Figure 8-1 The negative filter film shown in the figure is replaced by a negative filter sheet, which includes a light-transmitting optical element and a negative filter film coated on the surface of the optical element. For ease of distinction, the optical element coated with the negative filter film is called a carrier. After the negative filter film is prepared on the carrier, the carrier can be coupled and pasted on the lens so that the negative filter film is located in the optical path 1. The application does not limit the type of optical element in the negative filter sheet, for example, the optical element can have the function of the lens for collimating or converging the light beam, or the optical element can not have the function of the lens and not change the beam shape of the optical signal during transmission of the optical signal.

[0125] When a set of fiber optic connectors includes a pair of fiber optic connectors and an adapter, the example described above illustrates how a filtered connector can be implemented by introducing a negative filter film into the adapter. In other examples, a filtered fiber optic connection assembly can be implemented by introducing a negative filter film into the end face of the fiber, instead of introducing a negative filter film into the adapter.

[0126] In one possible implementation, a negative filter film can be deposited on the end face of fiber 1-1, or on the end face of fiber 1-2, or on both the end faces of fiber 1-1 and fiber 1-2, to realize a filter-type fiber optic connector. Figure 10-1 The diagram schematically shows a cross-sectional view of two fiber optic connectors connected via an adapter mating connection. Figure 10-1 In Figure 4 The example shown is an optical fiber 1-1 with negative filter films deposited on its end face and an optical fiber 1-2, respectively. Figure 10-1 As shown, the negative filter films on the end faces of fiber 1-1 and fiber 1-2 are denoted as negative filter film 1-1 and negative filter film 1-2, respectively. Because... Figure 10-1 and Figure 4 The only difference is that a negative filter film is added to the end face of the optical fiber, and the negative filter film is located on optical path 1. Therefore, for the sake of simplicity in the attached diagram, Figure 10-1 The labels for components other than the newly added component (i.e., the negative filter membrane) are not shown. For the labels and descriptions of other components, please refer to [reference needed]. Figure 4 The relevant content will be understood in detail here, and will not be repeated.

[0127] like Figure 10-1 As shown, a filter-type fiber optic connector can be realized simply by adding a negative filter film to the end face of the fiber. This helps to reduce the difficulty of converting existing fiber optic connectors in optical networks into filter-type fiber optic connectors, resulting in low network construction costs and high reliability.

[0128] In one possible implementation, a negative filter element can be fitted on the end face of fiber 1-1, or on the end face of fiber 1-2, or on both the end faces of fiber 1-1 and fiber 1-2, to realize a filter-type fiber optic connector.

[0129] Figure 10-2 In Figure 4 The example shown illustrates negative filter elements mounted on the end faces of optical fibers 1-1 and 1-2, respectively. This application does not limit the implementation method of mounting negative filter elements on the end faces of optical fibers, as long as the negative filter element can be fixed in the fiber ferrule and the negative filter film is located in optical path 1. For example, the negative filter element can be coupled and bonded to the end face of the optical fiber and / or bonded to the ferrule substrate.

[0130] The negative filter element mounted on the fiber end face can be understood by referring to the negative filter element mounted in the connecting via described earlier. For example,Figures 11-1 to 11-3 The cross-sections of fiber optic cable 1-1 and negative filter element 1-1 in the xy plane are schematically shown respectively. Figures 11-1 to 11-3 As shown, the negative filtering element may include a lens 1-1, a negative filter film 1-1 coated on the surface of the lens 1-1 away from the optical fiber 1-1, and an anti-reflective film 1-1 coated on the surface of the lens 1-1 facing the optical fiber 1-1. Optionally, the positions of the anti-reflective film 1-1 and the negative filter film 1-1 on the surface of the lens 1-1 can be interchanged. As described above regarding the negative filtering element in the connecting through-hole, the lens 1-1 can be replaced with other types of optical elements besides a lens, as long as the optical element can transmit light signals or transmit light; the negative filter film 1-1 can be replaced with a negative filter sheet; the anti-reflective film can be replaced with a negative filter film or a negative filter sheet; the surface of the lens 1-1 can be a plane or a curved surface, and so on.

[0131] This application does not limit the magnitude of the incident angle of the optical signal in optical path 1 on the antireflection film in the negative filter element. For example... Figure 11-1 As shown, the incident angle of the light signal on the antireflection film 1-1 can be 0 degrees, such as... Figure 11-2 or Figure 11-3 As shown, the angle of incidence can be greater than 0 degrees and less than 90 degrees.

[0132] This application does not limit the magnitude of the incident angle of the optical signal in optical path 1 on the negative filter film in the negative filter element. For example... Figure 11-1 and Figure 11-2 As shown, the incident angle of the optical signal on the negative filter film 1-1 can be 0 degrees, such as... Figure 11-3 As shown, the angle of incidence can be greater than 0 degrees and less than 90 degrees.

[0133] This application does not limit the angle between the antireflection film and the negative filter film in the negative filter element. For example... Figure 11-1 and Figure 11-3 As shown, the angle between the antireflection membrane 1-1 and the negative filter membrane 1-1 can be 0 degrees, or in other words, the two membranes are parallel to each other, or, as... Figure 11-2 As shown, the included angle can be greater than 0 degrees, or in other words, the two membranes are not parallel.

[0134] This application does not limit the surface of the lens coated with the negative filter film 1-1 to be flat; optionally, the surface can be curved. Similarly, this application does not limit the surface of the lens coated with the antireflective film to be flat; optionally, the surface can be curved.

[0135] When a negative filter element is installed in the fiber optic connector, this application does not limit the negative filter element to being coupled to the end face of the fiber. In some examples, the negative filter element can be installed inside the fiber, or in other words, the negative filter element separates the fiber in the ferrule into two segments. Figure 11-4As shown, the fiber 1-1 has a set of facets (denoted as facet 1-1a and facet 1-1b respectively) in the ferrule base 1-1, and the negative filter element 1-1 can be mounted between the facet 1-1a and the facet 1-1b, or in other words, the negative filter element 1-1 is coupled with the facet 1-1a and the facet 1-1b respectively. The negative filter element 1-1 can be understood with reference to any of the implementation manners of the negative filter element described above. For example, the negative filter element 1-1 can be a lens coated with a negative filter film, and optionally, different surfaces of the lens can be coated with an anti-reflection film.

[0136] In some examples, Figure 11-4 The facet 1-1a and / or the facet 1-1b can be coated with a negative filter film. When one of the facets is coated with a negative filter film, the other facet can be coated with an anti-reflection film.

[0137] Figure 11-4 For example, the internal part of the fiber 1-1 is mounted with a negative filter film and / or a negative filter element, and optionally, the internal part of the fiber 1-2 can also be mounted with a negative filter film and / or a negative filter element.

[0138] In the above, the adhesion is taken as an example of the way of fixing different elements together, and the application does not limit the way of fixing different elements together, for example, different elements can be fixed together by buckling or welding, etc.

[0139] The above describes examples of introducing a negative filter film into the connecting through hole of the adapter and introducing a negative filter film into the end face of at least one optical fiber. Optionally, a negative filter film can be introduced not only into the end face of an optical fiber but also into the connecting through hole of the adapter, which is conducive to reducing the reflectivity difference of a single negative filter film and reducing the preparation difficulty of the negative filter film. The application does not limit the number of negative filter films introduced in the optical path 1. Optionally, the optical path 1 includes one negative filter film, which can be mounted on the end face of an optical fiber, for example, the negative filter film is coated on the end face (or facet) of the fiber 1-1 or the fiber 1-2 or the negative filter element coupled with the end face (or facet) of the fiber 1-1 or the fiber 1-2, or the negative filter film can be mounted in the adapter, for example, the negative filter element where the negative filter film is located can be fixed in the connecting through hole. Optionally, the optical path 1 includes a plurality of negative filter films, which can be located on the end face (and / or facet) of the fiber 1-1 and the fiber 1-2, or on the end face (and / or facet) of an optical fiber and the adapter, or on the end face (and / or facet) of the fiber 1-1, the end face (and / or facet) of the fiber 1-2 and the adapter.

[0140] In the above, the optical fiber connector set includes an adapter. Alternatively, the optical fiber connector set can not include an adapter, and different optical fiber connectors can be directly matched and connected. In this scenario, as previously described, by introducing a negative filter film or a negative filter element into the optical fiber connector, a filter type optical fiber connector can be realized, and then a filter type optical fiber connector assembly can be realized.

[0141] In the above, the optical fiber connector set includes an adapter. Alternatively, the optical fiber connector set can not include an adapter, and different optical fiber connectors can be directly matched and connected. In this scenario, as previously described, by introducing a negative filter film or a negative filter element into the optical fiber connector, a filter type optical fiber connector can be realized, and then a filter type optical fiber connector assembly can be realized.

[0142] The number of optical fibers in the optical fiber connector is not limited in the present application. The first optical fiber connector and the second optical fiber connector can each include a plurality of optical fibers. After the two optical fiber connectors are matched and connected, a plurality of optical paths can be formed between the plurality of optical fibers of the first optical fiber connector and the plurality of optical fibers of the second optical fiber connector. One or more negative filter films can be introduced into at least two of the plurality of optical paths to improve the detection accuracy of a plurality of optical links using a single optical fiber connector assembly.

[0143] The way of introducing a negative filter film into an optical path can refer to the previous examples. The specific implementation of introducing a negative filter film into a plurality of optical paths is not limited in the present application.

[0144] For example, a negative filter element can be introduced into the connecting through hole of the adapter, and a plurality of negative filter films on the negative filter element are respectively located in a plurality of optical paths, or, as shown in Figure 6-2 , different film regions of a continuous negative filter film on the negative filter element can be located in different optical paths.

[0145] For example, a negative filter film can be introduced into the end face of each optical fiber in the first optical fiber ferrule. Figure 12-1 The cross section of the first optical fiber ferrule in the x-z plane is shown schematically. As shown in Figure 12-1 , the ferrule base body 1-1 of the first optical fiber ferrule is equipped with 7 optical fibers Figure 12-1 Each area filled with white in the figure represents a part of an optical fiber. The end face of each optical fiber is coated with a negative filter film or coupled with a negative filter element (as shown by the rectangle filled with dots in the figure).

[0146] Figure 12-1 For example, in some examples, the end face of a part of the optical fibers on the cross section can be equipped with a negative filter film or a negative filter element, and the end face of the other optical fibers can not be coated with a negative filter film or coupled with a negative filter element, and can be selectively coated with an anti-reflection film or coupled with a lens.

[0147] The present application does not limit the negative filter films or negative filter elements on the different fiber end faces to be independent of each other, and optionally, as shown in Figure 12-2 and Figure 12-3 a plurality of fibers can be coupled to the same lens, and the plurality of fibers are respectively coated with a plurality of independent negative filter films on the lens. The present application does not limit the shape of the negative filter film corresponding to each fiber, Figure 12-3 for example, the negative filter film is circular.

[0148] Optionally, as shown in Figure 6-2 a continuous negative filter film can be coated on the lens, and different film regions in the negative filter film are located on the light paths of different fibers to separate the data signals and detection signals on the corresponding light paths by different reflectivities.

[0149] When the fiber connection assembly introduces negative filter films on a plurality of light paths, negative filter films with different center wave bands and / or reflectivity differences can be introduced on different light paths as needed.

[0150] As previously described, the end face of the fiber or the optical element (such as a lens) located on the light path between the fiber end faces can be used as a carrier of the negative filter film, and then the negative filter film is assembled in the fiber connection assembly to realize the filter type fiber connection assembly. The present application does not limit the material of the optical element, for example, the material of the optical element can be glass or plastic, etc. However, through analysis, it is found that the expansion coefficient of the negative filter film is generally small, in order to avoid the deformation of the negative filter film due to the large deformation of the surface of the carrier and / or stress, temperature sensitivity design can be used to ensure the detection accuracy and accuracy of the link information, and to ensure the signal quality of the data signal.

[0151] For example, the negative filter film can be coated on a carrier with low expansion coefficient and / or low linear strain sensitivity, such as a carrier made of WMS15 (zero expansion coefficient glass) material, thereby reducing the performance degradation of the negative filter film due to deformation and / or stress, resulting in transmission of data signals at high reflectivity or transmission of detection signals at low reflectivity, etc. not only degrades the signal quality of the data signal, but also makes it difficult to ensure the detection accuracy and accuracy of the link information.

[0152] For example, when assembling the carrier in the fiber connection assembly, if it is necessary to paste the carrier coated with the negative filter film on other elements (such as lenses or other light-transmitting elements other than lenses), the other elements can be made of low expansion coefficient materials, thereby reducing the influence of environmental factors such as temperature drift on detection accuracy.

[0153] For example, to avoid deformation of the carrier due to deformation of the ferrule substrate and / or adapter, a ferrule substrate and / or adapter with a low coefficient of thermal expansion can be selected. Alternatively, a material with a low coefficient of thermal expansion can be selected for local areas in the fiber optic connection assembly used to fix or encircle the carrier or negative filter film.

[0154] Materials with a low coefficient of thermal expansion can refer to materials with a coefficient of thermal expansion of less than 15 ppm / degree Celsius.

[0155] The above, with reference to the accompanying diagrams, describes the implementation method of the filter-type fiber optic connection assembly. For example... Figure 1 As shown, a single optical link in an optical network system may include multiple fiber optic connectors. Optionally, the optical signal in a single optical link may pass through multiple filtered fiber optic connectors during transmission, and different filtered fiber optic connectors may be implemented using the same or different methods described above.

[0156] Optionally, the center wavelengths of different fiber optic connection components can be the same, while the reflectivity differences can be different. Figure 13 This schematically illustrates a local link in an optical network, such as... Figure 13 As shown, the optical network includes optical link a and optical link b, both of which pass through optical elements that cause some loss to the optical signal. Assuming the distance (denoted as L1) between fiber optic connector a-1 in optical link a and the detection device is less than the distance (denoted as L2) between fiber optic connector a-2 and the detection device, when the reflectivity difference between fiber optic connector a-1 and fiber optic connector a-2 is the same, the detection signal reaching fiber optic connector a-2 will have a lower signal strength. Therefore, the reflected detection signal will also have a lower signal strength, reducing the detection accuracy of the detection device for fiber optic connector a-2. This, in turn, hinders the detection device from improving the accuracy of link information based on the detection results of fiber optic connector a-2.

[0157] Considering that the signal strength of the detection signal decreases continuously with the transmission distance, the reflectivity of the fiber optic connection component a-1, which is closer to the detection device, can be configured to be less than that of the fiber optic connection component a-2, which is farther from the detection device. Figure 14-1 The diagram schematically illustrates the loss distribution curve of optical link a acquired by the detection device. The horizontal axis represents the length of the optical link, and the vertical axis represents the signal strength of the reflected signal. The horizontal axis of peak a-1 in the loss distribution curve represents the distance between fiber optic connector a-1 and the detection device, and the vertical axis represents the signal strength of the detected signal reflected by fiber optic connector a-1. The horizontal axis of peak a-2 in the loss distribution curve represents the distance between fiber optic connector a-2 and the detection device, and the vertical axis represents the signal strength of the detected signal reflected by fiber optic connector a-2. For example... Figure 14-1As shown, increasing the reflectivity of the fiber optic connector a-2 to the detection signal helps compensate for the signal strength of the detection signal reflected by the fiber optic connector a-2. This helps ensure the detection accuracy of both components and improves the accuracy of the link information. Furthermore, reducing the reflectivity of the fiber optic connector a-1 to the detection signal helps increase the transmission distance of the detection signal in the optical link, thereby increasing the length / detection range of the optical link that the detection device can detect.

[0158] Optionally, the center wavelengths of different fiber optic connection components can be different. Figure 14-2 The transmittance of fiber optic connector a-1 as a function of wavelength is schematically shown by a solid line, while the transmittance of fiber optic connector a-2 as a function of wavelength is schematically shown by a dashed line. Figure 14-2 As shown, the center wavelengths of fiber optic connectors a-1 and a-2 are λ1 and λ2, respectively. Thus, when the detection device sends a first detection signal with wavelength λ1 and a second detection signal with wavelength λ2 to optical link a, fiber optic connector a-1 transmits the first detection signal with higher reflectivity and transmits the second detection signal and data signal with lower reflectivity, while fiber optic connector a-2 transmits the second detection signal with higher reflectivity and transmits the first detection signal and data signal with lower reflectivity. This allows different fiber optic connectors to reflect different detection signals, thereby reducing the number of reflections with higher reflectivity experienced by a single detection signal during transmission, increasing the transmission distance of each detection signal, and ultimately increasing the length of the optical link that the detection device can detect.

[0159] The above application uses optical fiber to transmit optical signals as an example. Optionally, the optical fiber can be replaced with other types of media for transmitting optical signals. In some application scenarios, the optical fiber mentioned in this application can be replaced with optical cable or other types of optical transmission media.

[0160] The dimensions of the components in the accompanying drawings do not reflect actual dimensions; they are only used to illustrate the relative positional relationships between the components.

[0161] Those skilled in the art can clearly understand the specific working process of the system, device and unit described above for the convenience and brevity of description, which can refer to the corresponding process in the foregoing method examples, and will not be repeated here. The "A and / or B" involved in the examples of the present application can be understood as including both "A and B" and "A or B". The terms "first", "second", "third", "fourth" and the like in the specification and claims of the present application and the foregoing drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the terms thus used can be interchanged under appropriate circumstances, and this is only a distinguishing way adopted in the description of the examples of the present application for the objects with the same properties.

[0162] In several examples provided in the present application, it should be understood that the disclosed modules or devices or equipment can be implemented in other ways. For example, the device examples described above are only schematic. In addition, the coupling or direct coupling or communication connection between the shown or discussed each other can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical or other forms.

[0163] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the protection scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical fiber connector, characterized in that, The fiber optic connector includes a fiber optic ferrule and a housing for enclosing the fiber optic ferrule; The fiber ferrule includes a ferrule base and an optical fiber fixed in the ferrule base. The optical fiber is used for detachable connection to an optical link to transmit optical signals in the optical link. The optical signals in the optical link include data signals of different wavelengths and a first detection signal. The data signals are used to transmit information along the optical link, and the first detection signal is used to detect the reflectivity of the optical link. The fiber optic ferrule also includes an optical element located in the optical path of the fiber. The optical element is used to transmit the data signal and the first detection signal respectively. However, the reflectivity of the optical element to the first detection signal is greater than its reflectivity to the data signal.

2. The fiber optic connector according to claim 1, characterized in that, The optical element includes a negative filter film, which has a higher reflectivity for light signals in the target wavelength range than for light signals in other wavelength ranges outside the target wavelength range. The wavelength of the first detection signal belongs to the target wavelength range, and the wavelength of the data signal belongs to the other wavelength ranges.

3. The fiber optic connector according to claim 2, characterized in that, The other wavelength ranges are divided into at least two discontinuous sub-wavelength ranges by the target wavelength range.

4. The fiber optic connector according to claim 2 or 3, characterized in that, The width of the target wavelength range shall not exceed 20 nm.

5. The fiber optic connector according to any one of claims 2-4, characterized in that, The difference between the reflectivity of the negative filter film for optical signals in the target wavelength range and its reflectivity for optical signals in other wavelength ranges is greater than 1% and less than 80%.

6. The fiber optic connector according to any one of claims 2-5, characterized in that, The optical element also includes a light-transmitting element for transmitting optical signals in the optical link, and the negative filter film is coated on the surface of the light-transmitting element.

7. The fiber optic connector according to claim 6, characterized in that, The optical element also includes an anti-reflection coating, which and the negative filter film are deposited on different surfaces of the light-transmitting element.

8. The fiber optic connector according to any one of claims 1-7, characterized in that, The optical element is coupled to the end face of the optical fiber, or the optical element is located inside the optical fiber.

9. The fiber optic connector according to any one of claims 1-8, characterized in that, The optical signal in the optical link also includes a second detection signal, which is used to detect the reflectivity of the optical link, but the wavelength of the second detection signal belongs to the other wavelength range.

10. The fiber optic connector according to any one of claims 1-9, characterized in that, The first detection signal is sent from the optical time domain reflectometer (OTDR) to the optical link.

11. An optical fiber adapter, characterized in that, The fiber optic adapter has a connection through-hole for pluggable fiber optic ferrules that can accommodate at least two fiber optic connectors, so that optical fibers in different fiber optic ferrules can transmit optical signals in the same optical link. The optical signals in the optical link include data signals of different wavelengths and a first detection signal, wherein the data signals are used to transmit information along the optical link, and the first detection signal is used to detect the reflectivity of the optical link. An optical element is assembled in the connecting through hole. The optical element is used to transmit the data signal and the first detection signal respectively. However, the reflectivity of the optical element to the first detection signal is greater than its reflectivity to the data signal.

12. The fiber optic adapter according to claim 11, characterized in that, The optical element includes a light-transmitting element and a negative filter film coated on the surface of the light-transmitting element. The reflectivity of the negative filter film for light signals in the target wavelength range is greater than its reflectivity for light signals in other wavelength ranges outside the target wavelength range. Furthermore, the wavelength of the first detection signal belongs to the target wavelength range, and the wavelength of the data signal belongs to the other wavelength ranges.

13. The fiber optic adapter according to claim 12, characterized in that, The other wavelength ranges are divided into at least two discontinuous sub-wavelength ranges by the target wavelength range.

14. The fiber optic adapter according to claim 12 or 13, characterized in that, The width of the target wavelength range shall not exceed 20 nm.

15. The fiber optic adapter according to any one of claims 12-14, characterized in that, The difference between the reflectivity of the negative filter film for optical signals in the target wavelength range and its reflectivity for optical signals in other wavelength ranges is greater than 1% and less than 80%.

16. The fiber optic adapter according to any one of claims 11-15, characterized in that, The optical signal in the optical link also includes a second detection signal, which is used to detect the reflectivity of the optical link, but the wavelength of the second detection signal belongs to the other wavelength range.

17. The fiber optic adapter according to any one of claims 11-16, characterized in that, The first detection signal is sent from the optical time domain reflectometer (OTDR) to the optical link.

18. An optical fiber connection assembly, characterized in that, The fiber optic connection assembly includes at least two fiber optic connectors for mating connections, and at least one of the at least two fiber optic connectors is as described in any one of claims 1-10; or, The fiber optic connection assembly includes a fiber optic adapter and at least two fiber optic connectors for mating connection via the fiber optic adapter, wherein the fiber optic adapter is as described in any one of claims 11-17, and / or at least one of the at least two fiber optic connectors is as described in any one of claims 1-10.

19. A backlight panel, characterized in that, The optical backplane includes a substrate and one or more optical fibers fixed on the substrate, wherein at least one of the optical fibers is connected to an optical fiber connector as described in any one of claims 1-10.

20. An optical network system, characterized in that, The system includes a transmitter, a detection device, and an optical link, wherein the optical link includes the optical fiber connection assembly as described in claim 18 and multiple optical fibers connected by the optical fiber connection assembly. The transmitting end is used to send data signals carrying information to the optical link; The detection device is used to send a detection signal to the optical link; The optical link is used to transmit the data signal and the detection signal; The detection device is also used to detect the detection signal reflected by the optical link and to determine the reflectivity of the optical link based on the detection results.

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