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

Abstract

The present application provides an optical fiber connector, an optical fiber adapter, an optical fiber connection assembly, an optical backplane, and a system, for use in improving the detection precision of a detection device with respect to link information of an optical link. An optical element for transmitting a data signal and a detection signal at different reflectivity is introduced into an optical fiber connector and / or an optical fiber adapter, such that an optical fiber connection assembly transmits the data signal at low reflectivity, and transmits the detection signal at high reflectivity. In this way, the signal quality of the data signal is guaranteed, and the intensity of the detection signal reflected by the optical fiber assembly is increased, thereby improving the detection precision of a detection device with respect to an optical link.

Description

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

[0001] This application claims priority to the Chinese patent application No. CN202410606183.5, filed on May 15, 2024, and entitled "Optical fiber connector, optical fiber adapter, optical fiber connection assembly, optical backplane and system", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, in particular to an optical fiber connector, an optical fiber adapter, an optical fiber connection assembly, an optical backplane and a system. BACKGROUND

[0003] With the development of optical fiber communication technology, optical network systems such as passive optical network (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 add detection devices such as optical time domain reflectometer (OTDR). OTDR sends detection signals to the optical link to be detected and detects the backscattering signals and reflected signals of the detection signals in the optical link, determines the reflectivity (such as the loss distribution curve of the optical link) at each place in the optical link according to the detection results, 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 of the optical fiber connector.

[0004] 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

[0005] The present application provides an optical fiber connector, an optical fiber adapter, an optical fiber connection assembly, an optical backplane and a system for improving the detection accuracy of the OTDR.

[0006] In a first aspect, the present application provides an optical fiber connector, which comprises an optical fiber ferrule and a housing for wrapping the optical fiber ferrule; the optical fiber ferrule comprises a ferrule base and an optical fiber fixed in the ferrule base, the optical 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 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 reflectivity at different positions in the optical link; the optical fiber ferrule further comprises an optical element located in the optical path of the optical fiber, the optical element being used to respectively transmit 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.

[0007] The reflectivity of the optical element to the first detection signal being greater than the reflectivity of the optical element to the data signals is conducive to increasing the signal strength of the first detection signal reflected by the optical element in the case of transmitting the data signals at a lower reflectivity to ensure the signal quality of the data signals, thereby being conducive to the detection device (such as an OTDR) improving the accuracy of the detection result of the optical link based on the first detection signal.

[0008] As introduced above, the detection signal can be used to detect the reflectivity at different positions 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 being used to detect the change of the signal strength of the reflected detection signal with the receiving time, and determine the reflectivity at different positions 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 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.

[0009] 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 connector 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 connector, thereby improving the detection accuracy of the reflectivity thereof, and thus helping to improve 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 reception 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 reception time of the first detection signal reflected by the fiber connector. Thus, the signal strength of the first detection signal reflected by each position in the optical link can be more accurately determined, the detection accuracy of the reflectivity of each position in the optical link by the detection device can be improved, and thus the detection device can obtain more accurate link information according to the reflectivity of each position in the optical link.

[0010] The present 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.

[0011] The present application does not limit the number of optical fibers in the ferrule base. When the ferrule base includes multiple optical fibers, the optical fiber can be one of the optical fibers in the ferrule base. Alternatively, when the ferrule base includes multiple optical fibers, the optical fiber can be any one of at least two optical fibers in the ferrule base, and the at least two optical fibers can be all or a part of the optical fibers in the ferrule base. Correspondingly, the optical paths of the at least two optical fibers are each provided with the optical element, and the optical elements installed on the optical paths of the different two optical fibers can be the same optical element or two independent optical elements.

[0012] Optionally, the optical element includes a negative filter film, the reflectivity of the negative filter film to the optical signal of a target wavelength range is greater than the reflectivity of the negative filter film to the optical signal of other wavelength ranges other than 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 range.

[0013] 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 ordinary filter films.

[0014] Generally, the common filter film is used to selectively transmit light signals in a certain wavelength range (referred to as the central wavelength range of the common filter film), and the negative filter film is used to selectively filter out light signals in a certain wavelength range (referred to as the central wavelength range of the negative filter film). That is, unlike the common filter film which is used to transmit light signals in the central wavelength range with a lower reflectivity, the negative filter film is used to transmit light signals in 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 such that the central wavelength range includes the wavelength of the first detection signal and reducing the width of the central wavelength range, the wavelength range of the data signal transmitted by the negative filter film with a lower reflectivity can be increased, thereby improving the bandwidth of the optical fiber.

[0015] Compared with the fiber grating and the fiber waveguide, the negative filter film has a smaller volume, thereby facilitating the reduction of the size of the optical fiber connector and the miniaturization of the optical network device.

[0016] The other wavelength range can include part or all of the wavelengths other than the target wavelength range. Alternatively, the other wavelength range and the target wavelength range belong to a continuous wavelength range (referred to as the effective wavelength range), and the other wavelength range can include part or all of the wavelengths in the effective wavelength range other than the target wavelength range. For example, the effective wavelength range is 1200 nm to 1600 nm, or 1200 nm to 1700 nm.

[0017] Optionally, the data signal is all the light signals in the optical link for transmitting or carrying information.

[0018] Optionally, the other wavelength range is divided into at least two discontinuous sub-wavelength ranges by the target wavelength range. Alternatively, the other wavelength range can include at least two discontinuous sub-wavelength ranges, and the target wavelength range is located between different sub-wavelength ranges.

[0019] In this way, the wavelength of the first detection signal is closer to the wavelength of the data signal, or in other words, the average value of the wavelength of the data signal is more reflected, and since the optical elements or defects in the optical link generally have the same or similar reflectivity to light 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 in transmitting the data signal.

[0020] In one 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.

[0021] In another example, the target wavelength range can include at least two discontinuous 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.

[0022] 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, not only is it beneficial to save the wavelength resources of the optical link and improve the bandwidth of the optical link, but it is also beneficial to improve the accuracy of the detection result obtained based on the first detection signal.

[0023] 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.

[0024] Optionally, the difference (i.e., r1-r2) between the reflectivity (denoted as r1) of the negative filter film to the optical signal in the target wavelength range and the reflectivity (denoted as r2) of the negative filter film to the optical signal in the other wavelength range is greater than a first threshold value and less than a second threshold value. Assuming that r2 is very small and can be ignored, then r1 can be greater than the first threshold value and less than the second threshold value. The first threshold value can be 1%, 5%, 10%, etc., and the second threshold value can be 70%, 75%, 80%, 85%, 90%, etc. By limiting r1 to be greater than the first threshold value, it is beneficial to avoid the situation where the identification accuracy of the detection device to the first detection signal reflected by the optical element is too low due to r1 being too small, thereby reducing the optimization effect on the accuracy of the link information. By limiting r1 to be less than the second threshold value, it is beneficial to avoid the situation where the transmission distance of the first detection signal in the optical link is too small due to r1 being too large, thereby reducing the dynamic range of the detection device.

[0025] Optionally, the optical element is coupled with the end face of the optical fiber, or the optical element is located inside the optical fiber. In this way, the optical element can be flexibly installed in the existing optical fiber connector.

[0026] Optionally, the negative filter film is coated on the end face of the optical fiber, the end face is exposed on the surface of the ferrule base, and the end face faces the other optical fiber connector matched with the optical fiber connector.

[0027] Optionally, the optical fiber has at least one set of end faces inside the ferrule base, and the negative filter film is coated on at least one end face. Alternatively, the optical fiber includes discontinuous at least two optical fiber segments inside the ferrule base, and the end face of the optical fiber refers to the end face of the optical fiber segment facing the adjacent optical fiber segment, and a set of end faces includes two adjacent end faces on different optical fiber segments.

[0028] By coating the negative filter film on the end face or the end face of the optical fiber, the space occupied by the optical element in the optical fiber connector can be reduced, thereby reducing the size of the optical fiber connector.

[0029] Optionally, the optical element further includes a light-transmitting element, the light-transmitting element is used for transmitting the optical signal in the optical link, and the negative filter film is coated on the 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, the performance of the negative filter film can be ensured.

[0030] The light-transmitting element can be coupled with the end face or the end face of the optical fiber. Compared with introducing a grating or a waveguide into the optical fiber connector, by coupling the light-transmitting element coated with the negative filter film with the end face or the end face of the optical fiber, the modification of the components in the existing optical network can be reduced, and the modification cost can be reduced.

[0031] The light-transmitting element is coupled with the end face or the end face, which means that the light-transmitting element allows the optical signal to pass between the two, for example, the optical signal in the optical link received from the other optical connector matched with the optical fiber connector can be emitted through the light-transmitting element and then incident on the end face or the end face, and the optical signal in the optical link sent to the other optical connector matched with the optical fiber connector can be emitted through the end face or the end face and then incident on the light-transmitting element. The present application does not limit the implementation of the lens coupled with the end face or the end face of the optical fiber, and the lens can be fixed on the end face or the end face, or fixed on the optical fiber ferrule. The present application does not limit the implementation of the lens, for example, the lens can be fixed by pasting or buckling.

[0032] Optionally, the light-transmitting element can also have the function of changing the beam shape of the optical signal, for example, 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.

[0033] Optionally, a surface of the light-transmitting element is further coated with an anti-reflection film. In this way, the loss of the optical signal in the optical link on the optical element is reduced, and the signal quality of the data signal and the transmission distance of the first detection signal are improved. The anti-reflection film and the negative filter film are coated on different surfaces or different surface regions of the light-transmitting element.

[0034] Optionally, the optical signal in the optical link further includes a second detection signal, which is used to detect the reflectivity at various positions in 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, the signal intensity of the second detection signal reflected by the optical element is reduced, which not only helps to improve the length of the optical link that can be detected by the detection signal, but also helps 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 can be the same as or different from the wavelength of the data signal.

[0035] Optionally, the first detection signal and / or the second detection signal is sent by an optical time domain reflectometer (OTDR) to the optical link.

[0036] 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 low expansion coefficient or low linear strain sensitivity. In order to avoid deformation of the optical element due to the extrusion of the optical fiber ferrule, the material of the optical fiber ferrule can be selected to be a material with low expansion coefficient. The material with low expansion coefficient can refer to a material with a thermal expansion coefficient of not more than 15 ppm / degree Celsius.

[0037] The present application does not limit the direct matching connection of the optical fiber connector and the other optical fiber connector. Optionally, the optical fiber connector is used to match and connect with the other optical fiber connector through an optical fiber adapter.

[0038] In a second aspect, the application provides an optical fiber adapter, which has a connection hole inside, the connection hole being used to pluggably accommodate or insert 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 including 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 reflectivity at different positions in the optical link; and the connection hole is provided with an optical element, the optical element being used to respectively transmit 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.

[0039] 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 at a lower reflectivity to ensure the signal quality of the data signals, thereby being beneficial to a detection device (for example, an OTDR) to improve the accuracy of a detection result of the optical link based on the first detection signal.

[0040] As introduced above, the detection signal can be used to detect reflectivity at different positions 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 being used to detect the change of the signal strength of the reflected detection signal with the receiving time, and determine the reflectivity at different positions 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 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.

[0041] 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.

[0042] 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.

[0043] 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 described here.

[0044] The link information, the number of fibers in the ferrule base, the possible implementation manners and effects of the data signal and the other wavelength range can be respectively referred to the related introduction of the first aspect.

[0045] For example, when the ferrule base includes a plurality of optical fibers, the optical fibers of the ferrule of at least two optical 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.

[0046] 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.

[0047] The light-transmitting element can optionally further have 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.

[0048] The surface of the light-transmitting element can optionally be further coated with an anti-reflection film. This is advantageous for reducing the loss of the optical signal on the optical element in the optical link and improving 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.

[0049] The optical signal in the optical link can optionally further include 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 for reducing the signal intensity of the second detection signal reflected by the optical element, not only for improving the length of the optical link that can be detected by the detection signal, but also for 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.

[0050] The first detection signal and / or the second detection signal can optionally be sent by an optical time domain reflectometer (OTDR) to the optical link.

[0051] 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 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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, respectively.

[0058] Optionally, the two fiber connection components transmit the first detection signal at a higher reflectivity and transmit the data signal at a lower reflectivity. However, the two fiber connection components 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 advantageous for increasing the signal strength of the first detection signal reaching the second fiber connection component while ensuring the signal strength of the first detection signal reflected by the first fiber connection component, thereby increasing the signal strength of the first detection signal reflected by the second fiber connection component and improving the detection accuracy of the detection device for the first and second fiber connection components, and further improving the accuracy of the link information. In addition, reducing the reflectivity of the first fiber connection component for the first detection signal is advantageous for increasing the transmission distance of the first detection signal in the optical link, thereby being advantageous for increasing the length of the optical link that can be detected by the detection device.

[0059] 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.

[0060] 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.

[0061] Optionally, the detection signal can also include the second detection signal as described above. The optical elements in the first fiber connection component can transmit the first detection signal at a higher reflectivity and transmit the second detection signal at a lower reflectivity, while the optical elements in the second fiber connection component can transmit the first detection signal at a lower reflectivity and transmit the second detection signal at a higher reflectivity. In this way, it is not only advantageous to increase the signal strength of the detection signal reflected by the fiber connection component, but also advantageous to reduce the number of optical elements through which the first and second detection signals pass, and to increase the transmission distance of the first and second detection signals in the optical link, thereby being advantageous for increasing the dynamic range of the detection device.

[0062] The possible implementation manners and beneficial effects of the fiber connection assembly, the optical backplane and the system related to the fiber connector or the fiber 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

[0063] Fig. 1 schematically shows a possible structure of an optical network;

[0064] Fig. 2 schematically shows a curve of the transmittance of a negative filter film versus wavelength;

[0065] Fig. 3 schematically shows another curve of the transmittance of a negative filter film versus wavelength;

[0066] Fig. 4 schematically shows a cross-sectional view of two fiber connectors connected through an adapter;

[0067] Fig. 5 schematically shows another cross-sectional view of two fiber connectors connected through an adapter;

[0068] Fig. 6-1 schematically shows a cross section of a negative filter element in the x-y plane;

[0069] Fig. 6-2 schematically shows a surface of a negative filter element in the y-z plane;

[0070] Fig. 7 schematically shows another cross-sectional view of two fiber connectors connected through an adapter;

[0071] Fig. 8-1 schematically shows another cross section of a negative filter element in the x-y plane;

[0072] Fig. 8-2 schematically shows another cross-sectional view of two fiber connectors connected through an adapter;

[0073] Fig. 9, Fig. 10-1 and Fig. 10-2 respectively schematically show another cross-sectional view of two fiber connectors connected through an adapter;

[0074] Fig. 11-1 to Fig. 11-3 respectively schematically show a cross section of an optical fiber 1-1 and a lens 1-1 in the x-y plane;

[0075] Fig. 11-4 schematically shows a cross-sectional view of a fiber connection assembly with a negative filter element installed inside an optical fiber;

[0076] Fig. 12-1 and Fig. 12-2 respectively schematically show a cross section of a first fiber ferrule in the x-z plane;

[0077] Fig. 12-3 schematically shows a surface of the lens shown in Fig. 12-2 coated with a negative filter film;

[0078] Fig. 13 schematically shows a partial link in an optical network;

[0079] Figure 14-1 schematically shows a loss distribution curve of the optical link a acquired by the detection device;

[0080] Figure 14-2 schematically shows a transmittance curve of the fiber connection assembly a-1 with respect to wavelength by a solid line, and a transmittance curve of the fiber connection assembly a-2 with respect to wavelength by a dashed line. DETAILED DESCRIPTION

[0081] Optical network systems (or optical networks) are increasingly widely used. An optical network can include a transmitting end, a receiving end and an optical fiber link (or optical link). The transmitting end is configured to transmit an optical signal (referred to as a data signal) carrying data to the optical fiber link, the optical fiber link is configured to transmit the data signal to the receiving end, and the receiving end is configured to receive the data signal.

[0082] Figure 1 schematically shows a possible structure of an optical network. As shown in Figure 1, the optical network includes a service board 2, a backplane 1 and a switching board 3. The service board 2 is provided with a circuit unit 4, and the circuit unit 4 is connected to an optical fiber connector 6 on the backplane 1 through an optical fiber connector 5. The circuit unit 9 of the switching board 3 is connected to an optical fiber connector 7 on the backplane 1 through an optical fiber connector 8. The optical fiber connector 6 and the optical fiber connector 7 are signal connected to realize signal transmission between the circuit unit 4 on the service board 2 and the circuit unit 9 on the switching board 3.

[0083] The circuit unit 4 and the circuit unit 9 can be respectively configured as a transmitting end and a receiving end of data. For example, the circuit unit 4 is configured to transmit an optical signal (referred to as a data signal) carrying data, and the data signal is transmitted to the circuit unit 9 in sequence through an optical fiber on the service board 2, the optical fiber connector 5, the optical fiber connector 6, the optical fiber connector 8, the optical fiber connector 7 and an optical fiber on the switching board 3.

[0084] Alternatively, the circuit unit 4 and the circuit unit 9 can be respectively configured as a receiving end and a transmitting end. The circuit unit 9 is configured to transmit a data signal, and the data signal is transmitted to the circuit unit 4 in sequence through an optical fiber on the switching board 3, the optical fiber connector 7, the optical fiber connector 8, the optical fiber connector 6, the optical fiber connector 5 and an optical fiber on the service board 2.

[0085] A fiber optic connector is a reusable passive device used to connect two or more optical fibers to form a continuous optical path. The present application does not limit the type of fiber optic connector. For example, the fiber optic connector can be a single fiber connector such as a Ferrule Connector (FC) interface, a Lucent Connector (LC), or a Square Connector (SC), or the 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 implement a mechanical mating transmission, and the ferrule has a multi-core number (e.g., 2-96 cores).

[0086] The present application refers to a group of fiber optic connectors as a fiber optic connection assembly. FIG. 1 illustrates an example in which a fiber optic link includes two fiber optic connection assemblies. Alternatively, a single fiber optic link can include a greater or lesser number of fiber optic connection assemblies.

[0087] FIG. 1 illustrates an example in which the optical network is deployed on a single host or rack. The present application does not limit the size of the optical network. Alternatively, the transmitting end and the receiving end can be deployed on different hosts or different racks.

[0088] The present application does not limit the type of optical network. For example, the optical network can include any one or a combination of PON, optical transport network (OTN), optical access network (OAN), metropolitan area network (MAN), synchronous digital hierarchy (SDH), Ethernet, or flex Ethernet (FlexE) and wavelength division multiplexing (WDM) network. For example, the optical network illustrated in FIG. 1 is a PON. The transmitting end and the receiving end can be an OLT and an optical network unit (ONU), respectively, or an ONU and an OLT, respectively. The present application does not limit the access mode of the optical access network. For example, the access mode of the optical access network can be fiber to the home (FTTH) or direct connect (DC).

[0089] The present application does not limit the type of backplane. For example, the backplane can be an optical cross-connect (OXC) unit.

[0090] As optical networks are more and more widely used in the field of communications, there are more and more security, acceptance detection and routine maintenance services for optical networks. The 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 the OTDR to improve the maintenance efficiency of optical networks has a profound positive significance.

[0091] The present application does not limit the deployment of the OTDR in the optical network system. For example, the OTDR can be deployed in the sending end as described above. 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 signals and the detection signals can be combined into the measured optical fiber outside the sending end.

[0092] In the process of detecting the optical fiber link (referred to as the measured optical fiber link) in the optical network by 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 and transmission attenuation of the optical fiber in the optical link, 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.

[0093] Since the positions of the optical fiber connection assemblies in the optical link are usually known, the detection device can use the positions of the optical fiber connection assemblies 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.

[0094] However, in order to ensure the signal quality of the data signal, the quality of the optical link is continuously improved, and the loss of the signal at each element (including the optical fiber connection assembly) on the link is continuously reduced. When there is a defect in the optical link, the signal strength of the reflection signal generated by the defect is generally much greater than the signal strength of the reflection signal generated by the optical fiber connection assembly, resulting in a low identification accuracy of the OTDR for the optical connection assembly, and making it difficult to improve the accuracy of the link information based on the optical fiber connection assembly.

[0095] In order to improve the detection accuracy of the OTDR on the optical link (or improve the accuracy of the link information determined by the OTDR), the present application provides an optical fiber connection assembly, which transmits data signals and detection signals with the same low reflectivity as the existing optical fiber connection assembly, and is different from the existing optical fiber connection assembly. In the process of transmitting data signals and detection signals, the reflectivity of the detection signal of the optical fiber connection assembly provided by the present application is greater than the reflectivity of the data signal. In order to facilitate the distinction, the optical fiber connection assembly provided by the present application is referred to as a filtering type optical fiber connection assembly hereinafter. The present application also proposes deploying at least one filtering type optical fiber connection assembly in the optical link, which is beneficial to enhancing the signal strength of the detection signal reflected by at least one optical fiber connection assembly, thereby improving the detection accuracy of the detection device on the corresponding optical fiber connection assembly, and further improving the detection accuracy of the detection device on the optical link (for example, improving the spatial resolution), and on the other hand, it is beneficial to reducing the signal strength of the data signal reflected by the optical 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.

[0096] The present application does not limit the implementation of the filtering type optical 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 an optical fiber grating or an optical fiber waveguide or an optical filter can be assembled in the filtering type optical 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.

[0097] The optical fiber grating is a diffraction grating formed by axially periodically modulating the refractive index of the optical fiber core through a certain method, and is a passive filter device. Because the optical 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 optical fiber laser, optical fiber communication and sensing. The 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.

[0098] However, the volume of the grating, the waveguide and the optical filter is usually large, which is not conducive to the miniaturization of the fiber connection assembly. Moreover, the modification cost of assembling the grating or the waveguide in the existing optical network connection assembly is high, which increases the modification cost of the optical network.

[0099] It is found 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 spectrum. Figure 2 schematically shows the transmittance curve of the negative filter film with respect to the wavelength. The negative filter film has high reflectivity to the optical signal of the central waveband, so the central waveband presents low transmittance in the curve shown in Figure 2, and the negative filter film has low reflectivity to the optical signal of the wavelength outside the central waveband (referred to as low reflection waveband), so the low reflection waveband presents high transmittance in the curve shown in Figure 2. Since the curve of the negative filter film shown in Figure 2 is concave, the negative filter film is also commonly referred to as a concave negative filter film.

[0100] 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.

[0101] Based on the above findings, it is proposed in the present application that the preparation process or parameters of the negative filter film are adjusted so that 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 fiber connection assembly to realize a filtering type 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.

[0102] Compared with adjustment of the central waveband of the negative filter film and application of the common filter film in the fiber connection assembly, it is conducive to increasing the wavelength range of the data signal transmitted at a lower reflectivity by the fiber connection assembly, so as to be conducive to improving the bandwidth of the data signal transmitted by the fiber, and also conducive to avoiding introduction of the grating or the waveguide with a larger volume into the fiber connection assembly, so as to be conducive to reducing the volume of the fiber connector. In addition, compared with introduction of the grating or the waveguide into the fiber connection assembly, introduction of the negative filter film or the negative filter element into the fiber connection assembly is conducive to reducing the modification of the components in the existing optical network and reducing the modification cost.

[0103] The present application does not limit that the negative filter film has high transmittance to all wavelengths outside the central waveband, as long as the wavelength range of the low reflection waveband of the negative filter film is larger than the wavelength range of the high reflection waveband, which is conducive to 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 by the fiber connection assembly.

[0104] Figure 3 schematically shows another curve of the transmittance of the negative filter film versus wavelength. 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 band can be considered to include only one wavelength λ1, which is beneficial to further increase the wavelength range of the light signal transmitted by the negative filter film at a lower reflectivity, thereby increasing the bandwidth of the optical link. The negative filter film corresponding to the curve shown in Figure 3 is generally also referred to as an extremely narrow negative filter film.

[0105] Figures 2 and 3 are schematic diagrams of the transmittance of the negative filter film versus wavelength. 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 widths of the high reflection wavelength range and the low reflection wavelength range, nor does it limit the reflectivities corresponding to the low reflection wavelength range and the high reflection wavelength range, respectively.

[0106] Possible methods of introducing the negative filter film into the optical fiber connection assembly are described below.

[0107] In some examples, the optical fiber connection assembly can include two optical fiber connectors and an adapter. The optical fiber connector can include an optical fiber ferrule and a housing for wrapping the optical fiber ferrule, and one or more optical fibers are arranged in the optical fiber ferrule. For example, the optical fiber ferrule includes a ferrule base body having one or more through holes, and one or more optical fibers are respectively inserted into the one or more through holes. For ease of distinction, one of the optical fiber connectors is referred to as a first optical fiber connector, the other optical fiber connector is referred to as a second optical fiber connector, the optical fiber ferrules in the first optical fiber connector and the second optical fiber connector are referred to as a first optical fiber ferrule and a second optical fiber ferrule, respectively, the ferrule base body and the optical fiber in the first optical fiber ferrule are referred to as ferrule base body 1-1 and optical fiber 1-1, respectively, and the ferrule base body and the optical fiber in the second optical fiber ferrule are referred to as ferrule base body 1-2 and optical fiber 1-2, respectively. The two optical fiber connectors can be connected by matching the adapter, and Figure 4 schematically shows a cross-sectional view of the two optical fiber connectors when they are connected by matching the adapter. As shown in Figure 4, when the two optical fiber connectors are connected by matching the adapter, an optical path (referred to as optical path 1) can be formed between optical fiber 1-1 and optical fiber 1-2.

[0108] To achieve a filtered optical fiber connection assembly, it is proposed that an optical element coated with a negative filter film can be arranged in the connecting through hole of the adapter. For ease 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 resulting filtered connection assembly can be referred to as Figure 5. The difference between Figure 5 and Figure 4 is only that a negative filter element is added in the connecting through hole, and the negative filter element is located on the optical path 1. Therefore, in order to make the drawing simple, Figure 5 does not show the labels of other elements except the newly added element (i.e., the negative filter element), and the labels and introduction of other elements can be understood with reference to the related content of Figure 4, which will not be described here again.

[0109] As shown in FIG. 5, only a negative filter element is added in the connecting through hole of the adapter, and a filter type fiber connection assembly is realized, which is conducive to reducing the difficulty of transforming the fiber connection assembly in the existing optical network into the filter type fiber connection assembly, and the network construction cost is low and the reliability is high.

[0110] FIG. 6-1 schematically shows the cross section of the negative filter element in the x-y plane. As shown in FIG. 6-1, the negative filter element includes a lens and a negative filter film on the surface of the lens. FIG. 6-1 takes an example that the negative filter film is plated on the surface of the lens facing the fiber 1-2. Alternatively, the negative filter film can be plated on the surface of the lens facing the fiber 1-1, or respectively plated on the surface of the negative filter element facing the fiber 1-1 and the surface facing the fiber 1-2.

[0111] For the convenience of description, the surface area of the lens on which the negative filter film is plated is referred to as a target area in the present application. FIG. 6-1 takes an example that the entire area of the surface of the lens facing the fiber 1-2 is plated with the negative filter film. Alternatively, the target area can be a part of the area of the surface, as long as the target area is located on the light path 1. FIG. 6-2 schematically shows the surface of the negative filter element in the y-z plane. As shown in FIG. 6-2, the target area is a part of the area of the surface of the lens.

[0112] FIG. 5 takes an example that the assembly position of the negative filter element in the connecting through hole is such that the light path 1 is perpendicular to the negative filter film. The present application does not limit the angle between the negative filter film and the light path 1. As shown in FIG. 7, the angle between the light path 1 and the negative filter film can not be 90 degrees. For example, the negative filter element can be assembled according to the central angle of the negative filter film, so that the optical signal in the light path 1 is incident on the negative filter film at the central angle or an angle close to the central angle, to ensure the filtering effect of the negative filter film and to realize the required central waveband, reflectivity difference and return loss, etc.

[0113] The difference between FIG. 7 and FIG. 4 is only that the negative filter element is added in the connecting through hole, and the negative filter element is located on the light path 1. Therefore, in order to make the drawing simple, FIG. 7 does not show the labels of the elements other than the added element (i.e., the negative filter element), and the labels and introduction of the other elements can be understood with reference to the related contents of FIG. 4, which will not be described herein again.

[0114] The present application does not limit the distance between the end surface of the fiber and the surface of the negative filter element. FIG. 5 and FIG. 7 take an example that the distance between the end surface of the fiber and the surface of the filter film is greater than 0. In some examples, the distance between the end surface of the fiber and the surface of the filter film can be 0, or in other words, the end surface of the fiber can contact the surface of the filter film.

[0115] In order to reduce the loss of the light beam in the optical path 1, as shown in FIG. 8-1, the negative filter element can further include an anti-reflection film, and the anti-reflection film is also located on the optical path 1. As shown in FIG. 8-1, the surface of the lens of the negative filter element on which the anti-reflection film is coated is arranged opposite to the surface on which the negative filter film is coated. FIG. 8-1 takes the anti-reflection film parallel to the negative filter film as an example. When the central angles of the two are different, in order to ensure the optical performance of the two, the two can not be parallel.

[0116] In order to reduce the loss of the light beam in the optical path 1, as shown in FIG. 8-2, the end surface of the optical fiber 1-1 and the end surface of the optical fiber 1-2 can be coated with an anti-reflection film, respectively. Optionally, the end surface of the optical fiber 1-1 or the optical fiber 1-2 is coated with an anti-reflection film.

[0117] The difference between FIG. 8-2 and FIG. 4 is that a negative filter element is added in the connecting through hole, and an anti-reflection film is added on the end surface of the optical fiber. Therefore, in order to make the drawing simple, FIG. 8-2 does not show the labels of the elements other than the added element (i.e., the negative filter element), and the labels and introduction of the other elements can be understood with reference to the related contents of FIG. 4, which will not be repeated here.

[0118] In order to optimize the mode or beam shape of the optical signal in the optical path 1, as shown in FIG. 9, lens 1-1 and lens 1-2 can be further added in the optical fiber connecting assembly, and the lens 1-1 and the lens 1-2 are respectively located on the optical path 1, for adjusting the mode of the light beam in the optical path 1, such as adjusting the divergence angle, converging or collimating, etc., to improve the coupling efficiency of the optical fiber to the optical signal in the optical path 1, reduce the loss of the optical signal in the optical fiber connecting assembly, and improve the signal quality of the data signal and the detection signal.

[0119] The present 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).

[0120] The difference between FIG. 9 and FIG. 4 is that a negative filter element and a lens are added in the optical fiber connecting assembly, and the added elements are located on the optical path 1. Therefore, in order to make the drawing simple, FIG. 9 does not show the labels of the elements other than the added elements, and the labels and introduction of the other elements can be understood with reference to the related contents of FIG. 4, which will not be repeated here.

[0121] As shown in FIG. 9, the lens 1-1 is embedded in the ferrule base 1-1 and contacts the end surface of the optical fiber 1-1, and the lens 1-2 is embedded in the ferrule base 1-2 and contacts the end surface of the optical fiber 1-2. The present application does not limit the fixing way of the lens in the optical fiber ferrule, nor the positional relationship between the lens and the end surface of the optical fiber, as long as the lens and the end surface of the optical fiber are coupled or the lens and the end surface of the optical fiber are located on the optical path 1.

[0122] In some examples, the end face of the optical fiber can be processed such that the end face of the optical fiber also has the function of a lens.

[0123] 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 lens can be used to converge or collimate the light beam in the optical path 1, so as to improve the coupling efficiency of the optical fiber to the optical signal in the optical fiber connector assembly, reduce the loss of the optical signal in the optical fiber connector assembly, and improve the signal quality of the optical signal. The present application does not limit the function of the optical element to be a lens. As long as the optical element can transmit the optical signal, it is acceptable. The present 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 non-parallel. For example, the surface of the optical element can be a plane or a curved surface.

[0124] In some examples, the negative filter element can include a plurality of negative filter films. In other words, different negative filter films are located at different positions in the optical path 1. In other words, the optical signal in the optical path 1 can pass through a plurality of negative filter films during the transmission in the negative filter element. For example, the anti-reflection film shown in FIG. 8-1 can be replaced by a negative filter film. During the transmission of the optical signal in the negative filter element, the optical signal will pass through the negative filter film, the lens and another negative filter film in sequence. In this way, the requirement for the reflectivity difference of a single negative filter film is reduced, and the preparation difficulty of the negative filter film is reduced.

[0125] The foregoing takes the optical element in the negative filter element as an example of a single optical element for transmitting the optical signal (or referred to as light transmission). In some examples, the optical element can include a plurality of light-transmitting optical elements. The plurality of optical elements are respectively located on the optical path 1, and at least one optical element is coated with a negative filter film. For example, the negative filter film shown in FIG. 6-1 or FIG. 8-1 can be replaced by a negative filter sheet. The negative filter sheet includes a light-transmitting optical element and a negative filter film coated on the surface of the optical element. In order to distinguish, the optical element coated with the negative filter film is referred to as 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 on the optical path 1. The present application does not limit the type of optical element in the negative filter sheet. For example, the optical element can have the function of a lens, which can be used to collimate or converge the light beam, or the optical element can not have the function of a lens, which does not change the beam shape of the optical signal during the transmission of the optical signal.

[0126] When a set of optical fiber connectors includes a pair of optical fiber connectors and an adapter, the foregoing describes an example of introducing a negative filter film into the adapter to realize a filter type connector. In other examples, the negative filter film can not be introduced into the adapter, but a negative filter film can be introduced into the end face of the optical fiber to realize a filter type optical fiber connector assembly.

[0127] In a possible implementation, a negative filter film can be coated on the end face of the optical fiber 1-1 or on the end face of the optical fiber 1-2 or on the end faces of the optical fiber 1-1 and the optical fiber 1-2 to implement a filter type optical fiber connector. FIG. 10-1 schematically shows a cross-sectional view of two optical fiber connectors when matched and connected through an adapter. FIG. 10-1 takes the example that a negative filter film is coated on the end face of the optical fiber 1-1 and the end face of the optical fiber 1-2 shown in FIG. 4. As shown in FIG. 10-1, the negative filter films on the end face of the optical fiber 1-1 and the end face of the optical fiber 1-2 are respectively denoted as negative filter film 1-1 and negative filter film 1-2. Since the difference between FIG. 10-1 and FIG. 4 is only that a negative filter film is additionally coated on the end face of the optical fiber, and the negative filter film is located on the optical path 1, for the sake of simplicity of the drawing, FIG. 10-1 does not show the labels of the elements other than the newly added element (i.e., the negative filter film), and the labels and introduction of the other elements can be understood with reference to the related content of FIG. 4, which will not be repeated here.

[0128] As shown in FIG. 10-1, only the negative filter film needs to be additionally coated on the end face of the optical fiber to implement the filter type optical fiber connection assembly, which is conducive to reducing the difficulty of modifying the optical fiber connection assembly in the existing optical network into the filter type optical fiber connection assembly, and the network construction cost is low and the reliability is high.

[0129] In a possible implementation, a negative filter element can be assembled on the end face of the optical fiber 1-1 or on the end face of the optical fiber 1-2 or on the end faces of the optical fiber 1-1 and the optical fiber 1-2 to implement a filter type optical fiber connector.

[0130] FIG. 10-2 takes the example that a negative filter element is assembled on the end face of the optical fiber 1-1 and the end face of the optical fiber 1-2 shown in FIG. 4. The present application does not limit the implementation mode of assembling the negative filter element on the end face of the optical fiber, as long as the negative filter element can be fixed in the fiber ferrule, and the negative filter film is located on the optical path 1. For example, the negative filter element can be coupled and pasted on the end face of the optical fiber and / or pasted on the ferrule base.

[0131] The negative filter element assembled on the end face of the optical fiber can be understood with reference to the negative filter element assembled in the connection through hole as described above. For example, FIGS. 11-1 to 11-3 respectively schematically show the cross section of the optical fiber 1-1 and the negative filter element 1-1 in the x-y plane. As shown in FIGS. 11-1 to 11-3, the negative filter element can 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-reflection film 1-1 coated on the surface of the lens 1-1 toward the optical fiber 1-1. Alternatively, the positions of the anti-reflection film 1-1 and the negative filter film 1-1 on the surface of the lens 1-1 can be interchanged. As described above for the negative filter element in the connection through hole, the lens 1-1 can be replaced by other types of optical elements other than the lens, as long as the optical element can transmit the optical signal or be transparent; the negative filter film 1-1 can be replaced by a negative filter sheet; the anti-reflection film can be replaced by 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 the like.

[0132] The present application does not limit the size of the incident angle of the optical signal in the optical path 1 on the anti-reflection film in the negative filter element. As shown in FIG. 11-1, the incident angle of the optical signal on the anti-reflection film 1-1 can be 0 degree, as shown in FIG. 11-2 or FIG. 11-3, the incident angle can be greater than 0 degree and less than 90 degrees.

[0133] The present application does not limit the size of the incident angle of the optical signal in the optical path 1 on the negative filter film in the negative filter element. As shown in FIG. 11-1 and FIG. 11-2, the incident angle of the optical signal on the negative filter film 1-1 can be 0 degree, as shown in FIG. 11-3, the incident angle can be greater than 0 degree and less than 90 degrees.

[0134] The present application does not limit the size of the included angle between the anti-reflection film and the negative filter film in the negative filter element. As shown in FIG. 11-1 and FIG. 11-3, the included angle between the anti-reflection film 1-1 and the negative filter film 1-1 can be 0 degree, that is, the two films are parallel to each other, or, as shown in FIG. 11-2, the included angle can be greater than 0 degree, that is, the two films are not parallel.

[0135] The present application does not limit the surface of the lens coated with the negative filter film 1-1 to be a plane, and alternatively, the surface can be a curved surface. Similarly, the present application does not limit the surface of the lens coated with the anti-reflection film to be a plane, and alternatively, the surface can be a curved surface.

[0136] When the negative filter element is installed in the optical fiber connector, the present application does not limit the negative filter element to be coupled to the end face of the optical fiber. In some examples, the negative filter element can be installed inside the optical fiber, or in other words, the negative filter element divides the optical fiber in the ferrule base into two segments. As shown in FIG. 11-4, the optical fiber 1-1 has a set of sections (denoted as section 1-1a and section 1-1b, respectively) inside the ferrule base 1-1, and the negative filter element 1-1 can be installed between the section 1-1a and the section 1-1b, or in other words, the negative filter element 1-1 is coupled to the section 1-1a and the section 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. Optionally, different surfaces of the lens can be coated with an anti-reflection film.

[0137] In some examples, the section 1-1a and / or the section 1-1b shown in FIG. 11-4 can be coated with a negative filter film. When one of the end faces is coated with a negative filter film, the other section can be coated with an anti-reflection film.

[0138] FIG. 11-4 takes the example of installing the negative filter film and / or the negative filter element inside the optical fiber 1-1. Optionally, the optical fiber 1-2 can also be installed with a negative filter film and / or a negative filter element.

[0139] The above takes the example of adhesion as the way of fixing different elements to each other. The present application does not limit the way of fixing different elements together, for example, different elements can be fixed together by buckling or welding, etc.

[0140] The above respectively introduces the 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 the 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 present 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 assembled in the end face of one optical fiber, for example, the negative filter film is coated on the end face (or section) of the optical fiber 1-1 or the optical fiber 1-2 or the negative filter element coupled to the end face (or section) of the optical fiber 1-1 or the optical fiber 1-2, or the negative filter film can be assembled 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 in the end face (and / or section) of the optical fiber 1-1 and the optical fiber 1-2, or in the end face (and / or section) of one optical fiber and the adapter, or in the end face (and / or section) of the optical fiber 1-1, the end face (and / or section) of the optical fiber 1-2 and the adapter.

[0141] In the above examples, the set of fiber connectors includes adapters. Alternatively, the set of fiber connectors can not include adapters, and different fiber connectors can be directly matched and connected. In this scenario, a filtered fiber connector can be implemented by introducing a negative filter film or a negative filter element into the fiber connector, and a filtered fiber connector set can be implemented by introducing a negative filter film or a negative filter element into the fiber connector.

[0142] In the above examples, one optical fiber in the first fiber connector (i.e., optical fiber 1-1) and one optical fiber in the second fiber connector (i.e., optical fiber 1-2) are shown. After the two fiber connectors are matched and connected, the optical signal in optical fiber 1-1 can be transmitted to optical fiber 1-2 through optical path 1, and / or the optical signal in optical fiber 1-2 can be transmitted to optical fiber 1-1 through optical path 1.

[0143] The number of optical fibers in the fiber connector is not limited in the present application. The first fiber connector and the second fiber connector can each include multiple optical fibers. After the two fiber connectors are matched and connected, multiple optical paths can be formed between the multiple optical fibers of the first fiber connector and the multiple optical fibers of the second fiber connector. At least two of the multiple optical paths can be introduced with one or more negative filter films to improve the detection accuracy of multiple optical links using a single fiber connector set.

[0144] The way of introducing a negative filter film into an optical path can refer to the above examples. The specific implementation of introducing a negative filter film into multiple optical paths is not limited in the present application.

[0145] For example, a negative filter element can be introduced into the connecting through hole of the adapter, and multiple negative filter films on the negative filter element can be located in multiple optical paths, or, as shown in FIG. 6-2, different film regions of a continuous negative filter film on the negative filter element can be located in different optical paths.

[0146] Alternatively, for example, a negative filter film can be introduced into the end face of each optical fiber in the first fiber ferrule. FIG. 12-1 schematically shows the cross section of the first fiber ferrule in the x-z plane. As shown in FIG. 12-1, the ferrule base 1-1 of the first fiber ferrule is equipped with 7 optical fibers (each area filled with white in FIG. 12-1 represents a part of an optical fiber), and the end face of each optical fiber is coated with a negative filter film or coupled with a negative filter element (as shown in the rectangle filled with dots in the figure).

[0147] FIG. 12-1 takes the example that the end face of each optical fiber in the cross section is equipped with a negative filter film or a negative filter element. In some examples, the end face of a part of the optical fibers in 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.

[0148] The application does not limit the negative filter films or negative filter elements on different fiber end faces to be independent of each other. Optionally, as shown in FIG. 12-2 and FIG. 12-3, a plurality of optical fibers can be coupled to the same lens, and the lens is coated with a plurality of negative filter films independent of each other for the plurality of optical fibers. The application does not limit the shape of the negative filter film corresponding to each optical fiber. FIG. 12-3 takes the circular negative filter film as an example.

[0149] Optionally, as shown in FIG. 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 different optical paths of the optical fibers to separate the data signals and detection signals on the corresponding optical paths by different reflectivities.

[0150] When the negative filter film is introduced into the optical fiber connection assembly on a plurality of optical paths, the negative filter films with different central wavelength bands and / or reflectivity differences can be introduced into different optical paths as needed.

[0151] As introduced above, the end face of the optical fiber or the optical element (such as a lens) located on the optical path between the end faces of the optical fibers can be used as a carrier of the negative filter film, and then the negative filter film is assembled in the optical fiber connection assembly to realize the filter type optical fiber connection assembly. The 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, it is found through analysis that the expansion coefficient of the negative filter film is generally small. In order to avoid the deformation and / or stress of the negative filter film caused by the large deformation of the surface of the carrier, temperature sensitivity design can be adopted to ensure the detection accuracy and accuracy of the link information and to ensure the signal quality of the data signal.

[0152] 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, so as to reduce the performance degradation of the negative filter film caused by deformation and / or stress, resulting in transmission of data signals at high reflectivity or transmission of detection signals at low reflectivity, etc. Not only the signal quality of the data signal is degraded, but also it is difficult to ensure the detection accuracy and accuracy of the link information.

[0153] For example, when the carrier is assembled in the optical fiber connection assembly, if it is needed to paste the carrier coated with the negative filter film on other elements (such as a lens or other light-transmitting elements other than the lens), the other elements made of low expansion coefficient material can be selected, so as to reduce the influence of environmental factors such as temperature drift on the detection accuracy.

[0154] For example, in order to avoid the deformation of the carrier caused by the deformation of the ferrule base and / or the adapter, the ferrule base and / or the adapter with low thermal expansion coefficient can be selected, or the local area for fixing or looping the carrier or the negative filter film in the optical fiber connection assembly is selected to be made of a material with low thermal expansion coefficient.

[0155] The material with low thermal expansion coefficient can refer to a material with a thermal expansion coefficient less than 15 ppm / degree Celsius.

[0156] The above describes the implementation of the filtering type fiber connection assembly in combination with the drawings. As shown in FIG. 1, a single optical link in an optical network system can include multiple fiber connection assemblies. Alternatively, the optical signal in a single optical link can pass through multiple filtering type fiber connection assemblies during transmission, and different filtering type fiber connection assemblies can be implemented in the same or different manners as described above.

[0157] Alternatively, the center wavelengths of different fiber connection assemblies can be the same, and the reflectivity difference can be different. FIG. 13 schematically shows a partial link in an optical network. As shown in FIG. 13, the optical network includes optical link a and optical link b, both of which pass through optical elements with certain loss to optical signals. Assuming that the distance (denoted as L1) between fiber connection assembly a-1 in optical link a and the detection device is less than the distance (denoted as L2) between fiber connection assembly a-2 in optical link a and the detection device, when the reflectivity difference of fiber connection assembly a-1 and fiber connection assembly a-2 is the same, since the signal strength of the detection signal reaching fiber connection assembly a-2 is lower, the signal strength of the detection signal reflected by fiber connection assembly a-2 is lower, which will reduce the detection accuracy of the detection device to fiber connection assembly a-2, and further adversely affect the detection device to improve the accuracy of link information based on the detection result of fiber connection assembly a-2.

[0158] Considering that the signal strength of the detection signal continuously decreases with the transmission distance, the reflectivity of fiber connection assembly a-1 closer to the detection device to the detection signal can be configured to be less than the reflectivity of fiber connection assembly a-2 farther from the detection device to the detection signal. FIG. 14-1 schematically shows the loss distribution curve of optical link a obtained 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 of the detection signal. The horizontal coordinate of the peak a-1 in the loss distribution curve represents the distance between fiber connection assembly a-1 and the detection device, and the vertical coordinate represents the signal strength of the detection signal reflected by fiber connection assembly a-1. The horizontal coordinate of the peak a-2 in the loss distribution curve represents the distance between fiber connection assembly a-2 and the detection device, and the vertical coordinate represents the signal strength of the detection signal reflected by fiber connection assembly a-2. As shown in FIG. 14-1, by increasing the reflectivity of fiber connection assembly a-2 to the detection signal, the signal strength of the detection signal reflected by fiber connection assembly a-2 is compensated. In this way, the detection accuracy of the detection device to both is ensured, and the accuracy of the link information is improved. In addition, reducing the reflectivity of fiber connection assembly a-1 to the detection signal is beneficial to increase the transmission distance of the detection signal in the optical link, thereby increasing the length / detection range of the optical link that can be detected by the detection device.

[0159] Optionally, the central wavelengths of different fiber connection assemblies can be different. FIG. 14-2 schematically shows the transmittance of fiber connection assembly a-1 with respect to wavelength by a solid line, and schematically shows the transmittance of fiber connection assembly a-2 with respect to wavelength by a dashed line. As shown in FIG. 14-2, the central wavelengths of fiber connection assembly a-1 and fiber connection assembly a-2 are λ1 and λ2, respectively. In this way, when the detection device sends a first detection signal with a wavelength of λ1 and a second detection signal with a wavelength of λ2 into optical link a, fiber connection assembly a-1 transmits the first detection signal with a higher reflectance and transmits the second detection signal and the data signal with a lower reflectance, and fiber connection assembly a-2 transmits the second detection signal with a higher reflectance and transmits the first detection signal and the data signal with a lower reflectance. This facilitates different fiber connectors to reflect different detection signals, thereby reducing the number of times a single detection signal experiences reflection with a large reflectance during transmission, increasing the transmission distance of each detection signal, and facilitating increasing the length of the optical link that can be detected by the detection device.

[0160] In the above, the present application takes optical link using optical fiber to transmit optical signals as an example. Optionally, the optical fiber can be replaced by other types of media for transmitting optical signals. In some application scenarios, the optical fiber mentioned in the present application can be replaced by an optical cable or other types of optical transmission media or medium.

[0161] The size ratio of the components in the drawings of the present application does not reflect the true size ratio, but only expresses the relative positional relationship between the components.

[0162] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method examples, which will not be described 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 above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, which is only a way of distinguishing the objects with the same attributes in the description of the examples of the present application.

[0163] In several examples provided by 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 displayed or discussed objects can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical or other forms.

[0164] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some of the technical features can be replaced by equivalents; 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 by, The optical fiber connector comprises an optical fiber ferrule and a housing for wrapping the optical fiber ferrule; The optical fiber ferrule comprises a ferrule base and an optical fiber fixed in the ferrule base, the optical 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 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 reflectivity of the optical link; The optical fiber ferrule further comprises an optical element located in an optical path of the optical fiber, the optical element being used to respectively transmit 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.

2. The fiber optic connector of claim 1, wherein, The optical element comprises a negative filter film, the reflectivity of the negative filter film to optical signals of a target wavelength range is greater than the reflectivity of the negative filter film to optical 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.

3. The fiber optic connector of claim 2, wherein, The other wavelength ranges are discontinuous at least two sub-wavelength ranges separated by the target wavelength range.

4. The fiber optic connector of claims 2 or 3, wherein, The width of the target wavelength range is not more than 20 nm.

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

6. The fiber optic connector of any one of claims 2-5, wherein, The optical element further comprises a light-transmitting element, the negative filter film is coated on a surface of the light-transmitting element.

7. The fiber optic connector of claim 6, wherein, The optical element further comprises an anti-reflection film, the anti-reflection film and the negative filter film are coated on different surfaces of the light-transmitting element.

8. The fiber optic connector of any one of claims 1-7, wherein, The optical element is coupled with an end surface of the optical fiber, or the optical element is located inside the optical fiber.

9. The fiber optic connector of any one of claims 1-8, wherein, The optical signals in the optical link further comprise a second detection signal, the second detection signal is used to detect reflectivity of the optical link, but the wavelength of the second detection signal belongs to the other wavelength ranges.

10. The fiber optic connector of any one of claims 1-9, wherein, The first detection signal is sent by an optical time domain reflectometer (OTDR) to the optical link.

11. An optical fiber adapter, comprising: The optical fiber adapter has a connection through hole therein, the connection through hole being used to pluggably accommodate optical fiber ferrules of at least two optical fiber connectors to make optical fibers in different optical fiber ferrules transmit optical signals in a same optical link, the optical signals in the optical link comprising 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 reflectivity of the optical link; The connection through hole is provided with an optical element, the optical element being used to respectively transmit 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.

12. The fiber optic adapter of claim 11, wherein, The optical element comprises a light-transmitting element and a negative filter film plated on the surface of the light-transmitting element, the negative filter film has a reflectivity to light signals in a target wavelength range greater than its reflectivity to light signals in other wavelength ranges other than 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.

13. The fiber optic adapter of claim 12, wherein, The other wavelength ranges are separated by the target wavelength range into at least two sub-wavelength ranges which are discontinuous.

14. The fiber optic adapter of claims 12 or 13, wherein, The width of the target wavelength range is not more than 20 nm.

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

16. The fiber optic adapter of any one of claims 11-15, wherein, The optical signals in the optical link further comprise a second detection signal, the second detection signal is used to detect the reflectivity of the optical link, but the wavelength of the second detection signal belongs to the other wavelength ranges.

17. The fiber optic adapter of any one of claims 11-16, wherein, The first detection signal is sent by an optical time domain reflectometer (OTDR) to the optical link.

18. A fiber optic connection assembly, comprising: The optical fiber connection assembly comprises at least two optical fiber connectors for matching connection, and at least one of the at least two optical fiber connectors is as claimed in any one of claims 1-10; or, The optical fiber connection assembly comprises an optical fiber adapter and at least two optical fiber connectors for matching connection through the optical fiber adapter, and the optical fiber adapter is as claimed in any one of claims 11-17, and / or at least one of the at least two optical fiber connectors is as claimed in any one of claims 1-10.

19. An optical backplane, comprising: The optical backboard 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 claimed in any one of claims 1-10.

20. An optical network system, characterized by The system comprises a sending end, a detection device and an optical link, wherein the optical link comprises an optical fiber connection assembly as claimed in claim 18 and a plurality of optical fibers matching connected through the optical fiber connection assembly; The sending end is used to send a data signal 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 further used to detect the detection signal reflected by the optical link, and determine the reflectivity of the optical link according to the detection result.

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