CN117554034A - Method, system and device for measuring coupling coefficient of distributed side pumping optical fiber - Google Patents
Method, system and device for measuring coupling coefficient of distributed side pumping optical fiber Download PDFInfo
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Abstract
The invention discloses a method, a system and a device for measuring coupling coefficients of a distributed side pumping optical fiber, relates to the technical field of optical fiber coupling coefficient measurement, provides a novel separation method measuring method which is more practical, better in fault tolerance and higher in sensitivity based on a coupling theoretical model in DSCCP optical fiber, combines a separation method and a cut-off method to provide a self-adaptive measuring system under different lengths, improves measuring precision, designs a measuring device capable of quickly and automatically measuring the coupling coefficients according to the system, has stronger adaptability and application value under various schemes, has feasibility and wide application prospect in engineering, solves the problem that the measuring data sampling points of the existing method in an actual measurement are too few in a severe change area, can doubly improve the measuring data quantity of a transition area, improves the accuracy of a power change graph along with the length, and improves the accuracy of coupling coefficient measurement.
Description
Technical Field
The invention relates to the technical field of optical fiber coupling coefficient measurement, in particular to a method, a system and a device for measuring the optical fiber coupling coefficient of a distributed side pump.
Background
Under the background of rapid development and large-scale application of the current laser technology, the high-power fiber laser gradually improves the market occupation rate in the fields of advanced manufacturing, national defense safety, medical technology, scientific research and the like based on the characteristics of good beam quality, higher conversion efficiency, rich optical performance, convenient thermal management requirements and the like, and plays an increasingly important role in the whole laser application market. With the proposal of double-cladding pumping technology and the rapid development of passive optical fiber devices, high-power optical fiber lasers gradually transition from a spatial structure to an all-fiber structure. Due to the limited coupling size of the spatial structure, the rapid increase of the laser power is accompanied by the synchronous increase of the power density, which greatly increases the probability of thermally induced damage to the pump end face, and reduces the system stability in a high-power working state. In contrast, in the all-fiber waveguide system, laser is not passed through the space coupling assembly and is always constrained in the optical fiber, and the influence of disturbance caused by factors such as environment on the laser operation can be obviously reduced, so that the laser system is more compact and stable, and the application scene and the environmental adaptability of the optical fiber laser are definitely further expanded.
In fiber lasers, the ability of the pump laser to couple directly determines the upper limit of the laser output capability. The pump coupling mode can be divided into two modes, namely end-pumping injected from the transverse section of the fiber and side-pumping injected from the side of the fiber, according to the position of the laser when the laser is injected into the inner cladding of the gain fiber. The end-pumped beam combiner is required to be used in the former, because the cross section size of the optical fiber is extremely small, the local power density is extremely high at the injection position of the high-power pump, the problems of heating, burning and the like are extremely easy to occur, the power lifting capacity is limited, and meanwhile, the preparation technology and the performance of the end-pumped beam combiner also restrict the pump coupling capacity. In side pumping, this problem can be alleviated in theory, due to the large increase in side coupling area. As one of the side pumping modes, distributed side-coupled cladding-pumped (abbreviated as DSCCP, also called GTwave, composite fiber, etc. in different occasions) adopts a preparation method of multi-fiber parallel-beam drawing, expands the coupling area to the whole section of fiber, effectively avoids the problem of local heating which is difficult to solve in an end-pumped beam combiner, and has more excellent performance in nonlinear control and thermal distribution. The DSCCP laser provides more ideas in the aspects of power expansion level and structural design flexibility, and in recent years, a plurality of concerns are brought about at home and abroad, and the output power also realizes a series of milestone spans, which are different from the traditional optical fiber laser in appearance. The unique structure of the optical fiber is different from the traditional method in the manufacturing process, and the multi-fiber parallel-beam drawing scheme is required to overcome a plurality of problems in the preparation of the traditional optical fiber drawing equipment, including the difficulty in accurately controlling the transverse dimension of the optical fiber, the relative position of a prefabricated rod, the uniformity of materials and the like, so that the high-power design requirement is difficult to achieve.
Conventional double-clad gain fibers (shown in FIG. 1) commonly used today consist of a rare-earth doped silica core, a pure Dan Yingna cladding, and a low index outer cladding. The DSCCP is different from the DSCCP in that the cross section of the DSCCP is composed of a signal optical fiber comprising a fiber core and an inner cladding and a plurality of multimode pump optical fibers (the number is N and N is more than or equal to 1, and the degradation is carried out to the traditional double-cladding pump optical fibers when N=0), and the DSCCP is structurally shown in fig. 2-5, wherein A represents the signal optical fiber and B represents the pump optical fiber.
In dscp pumping, the coupled absorption gain amplification process can be split into two steps. The first step is a side coupling process of pump laser, wherein the pump light is injected through the end face of the pump fiber, then is transmitted in the pump fiber, and is coupled between the pump fiber and the inner cladding of the signal fiber through the tightly attached fiber side face in the form of evanescent wave, and the process determines that the pump light enters the signal fiber from the pump fiber. The second step is an absorption amplification process, in which the pump light coupled into the inner cladding of the signal fiber is absorbed and converted by the doped fiber core in the central region thereof, and the signal light in the fiber core is expected to realize gain amplification, and the second step is similar to the gain amplification in the conventional double-cladding gain fiber. Therefore, in DSCCP, the greatest difference from the physical process in conventional double-clad gain fiber results from the side coupling in the first step, and the strength of the coupling of the pump fiber into the signal fiber, i.e. the magnitude of the coupling coefficient, is the basis for the subsequent second step absorption amplification, which plays a decisive role in the overall fiber conversion efficiency.
In order to fully understand the laser conversion mechanism in DSCCP and quantitatively analyze the coupling constant related concepts, a brief description of the DSCCP fiber model is provided below, with a (1+1) -type fiber being used as an example. Introducing absorption coefficient alpha, coupling coefficient k 1 、k 2 (wherein k 1 Representing the coupling coefficient, k, of energy from the pump fiber into the signal fiber inner cladding 2 Then representing the coupling coefficient of the opposite process), in fact, due to non-uniform concentration distribution along the axial direction (z-direction in the cylindrical coordinates) or different transverse modes of the fiber attachment, α, k in the material preparation 1 、k 2 Each as a function of the coordinate z, but for simplicity here alpha, k 1 、k 2 Assuming that the equivalent average coefficient after all effects are taken into account and is the same everywhere in the axial direction, i.e. no longer a function with respect to z, is a constant value, it is related to the pump power P in the pump fiber 1 And pump power P in signal fiber 2 The relationship of (2) is as follows:
P 1 (z)、P 2 (z) represents the pump power at the coordinate z in the inner cladding of the pump fiber and the signal fiber, respectively.
Here, first consider the case where the absorption coefficient is zero (i.e., α=0), then the signal core also has no gain capability. When the injection power from the pumping fiber z=0 is P 0 When pumping laser, the signal fiber is not injected, namely P 1 (0)=P 0 ，P 2 (0) =0, its expression as a function of z is as follows:
p when z goes to infinity 1 And P 2 The limit values of (2) are as follows:
from this formula, it can be seen that P is not absorbed 1 And P 2 Gradually tend to stabilize with a ratio of P 1 /P 2 =k 2 /k 1 . Redefining the coupling length L as the length of the optical fiber at which the coupling power reaches the limit value (1-1/e), from the formula (k) 1 +k 2 ) =1/L, simultaneous workable k 1 And k 2 Specific values.
In practical applications, the signal fiber of the dscp optical fiber must be doped with an absorbing capacity (α+.0), and the final result must be different from the result obtained when α=0, and experimental measurement resultsThe power curve is the coupling (k 1 、k 2 ) The comprehensive effect of the optical fiber and the absorption (alpha) can not be directly decoupled and analyzed, which brings great difficulty to the research of the optical fiber preparation technology. In practice, since the absorption coefficient in the dscp optical fiber is affected by many geometric factors, if the α value obtained by changing the geometric size or the structure measurement cannot be directly applied to the dscp optical fiber, α obtained by directly preparing the same doped preform into an equal-size dual-cladding gain optical fiber (i.e., the first structure in fig. 1) cannot represent the α value of the same preform in the dscp, and there is a difference between the two values, and there is no accurate reference meaning.
Thus, a more rational approach is to first prepare an undoped DSCCP fiber in the core, i.e. α=0, and measure k by the method described above 1 And k 2 Accurate value, the coupling process (k 1 、k 2 ) Accurate measurements are made. The same size core doped DSCCP fiber is then prepared by the same drawing process, under the same process conditions and the same geometry and material composition except for the core, the coupling capability can be considered the same in both cases (i.e., k 1 、k 2 The corresponding values are the same in both cases α=0 and α+.0), so that the measured result in the core doping case can be attributed to the effect of α, thus achieving a two-step decoupling.
For accurate measurement of k 1 And k 2 Numerical values, i.e. P, are required to measure the power distribution in the pump and signal fibers over the length of the fiber 1 (z)、P 2 (z) the prior art adopts a cutting method to measure P for optical fibers with different lengths z 1 、P 2 It is sufficient, as shown in FIG. 6. The specific method comprises the following steps: injecting pump light from one end of the pump fiber, separating the signal fiber from the pump fiber at the other end, and measuring the power P of the pump fiber and the signal fiber respectively 1 、P 2 And the length L of the optical fiber at this time is noted. Then cut off a certain length DeltaL, and continuously measure the power P 'of the pumping fiber and the signal fiber according to the operation' 1 、P' 2 Recording the length L' =L-DeltaL of the optical fiber, repeating the above process until the whole optical fiber is cut off, thereby obtainingAll data are grouped and classified to obtain P 1 (z) and P 2 (z)。
From the power coupling graph (fig. 7), it was found that at different lengths z, P 1 (z) and P 2 There is a large difference in the rate of change of (z). At the coupling end with larger z value, P 1 (z) and P 2 (z) gradually becomes gentle and the change rate is low. And at the coupling start point with smaller z value, P 1 (z) and P 2 (z) respectively, rapidly varies in a near-exponential fashion. The truncation method is straightforward and operable, but it has certain imperfections when applied to dscp. For accurately measuring P of output of end of optical fiber 1 (z) and P 2 (z) the fiber ends need to be cut at an oblique angle and re-cut is required for each test for a different z. But is limited by the requirement of DSCCP 'two-in-one' cling type structure on length (single optical fiber length) when the optical fiber cutting knife cuts>25 cm), each time the cut-off test requires re-stripping a longer coating of the optical fiber, separating the two optical fibers, cleaning the surfaces, and then placing the two bare quartz fibers into a cutter for cutting. This process requires reprocessing tens of centimeters of fiber each time and once the failed cut fiber breaks, no measurement can be made of the length z, and the sampling location z can only be skipped to the next cut length. At the coupling end P 1 (z) and P 2 (z) changes slowly with less impact on the results, but at the exponentially varying end of the coupling onset, few data sampling points over short distances can cause significant bias to the measurement results. Therefore, in the scheme, the step length is large, so that the sampling points are few, and the problem of jumping the sampling points due to the breakage of the optical fiber causes larger measurement deviation in the area with severe power change, and the accurate coupling coefficient cannot be obtained through measurement efficiently and reliably.
Disclosure of Invention
The invention aims to provide a method, a system and a device for measuring the coupling coefficient of a distributed side-pumped optical fiber, which are used for calculating the coupling coefficient of the optical fiber by combining actual data and a theoretical model, providing a more convenient method for parameter design and test of DSCCP, solving the problem that the sampling points of the measured data in a severe change area are too small in the actual measurement by the traditional method, being capable of exponentially improving the measured data quantity in a transition area, improving the precision of a graph of power along with the length change and improving the accuracy of coupling coefficient measurement.
In order to achieve the above object, the present invention provides the following solutions:
the invention provides a method for measuring coupling coefficient of a distributed side pump optical fiber, which comprises the following steps:
(1) Removing coating layers from two ends of the optical fiber, and cleaning the surfaces of bare fibers at two ends;
(2) On the fiber injection end side: separating the pumping fiber from the signal fiber bare fiber, cutting the tail end of the pumping fiber into a flat angle, cutting the tail end of the output fiber of the matched light source laser into a flat angle, then welding the tail end of the matched light source laser with the tail end of the pumping fiber, cutting the tail end of the signal fiber into an oblique angle, and aligning the tail end face of the signal fiber with a light receiving cylinder to collect stray light;
(3) On the fiber output side: dividing a pumping fiber and a signal fiber bare fiber, respectively cutting the tail ends of the two bare fibers into oblique angles, respectively aligning the centers of photosensitive surfaces of the two power meters with the end surfaces of the pumping fiber and the signal fiber bare fiber, wherein the measuring range of the power meters is matched with the maximum output power of a light source laser;
(4) Measuring the length of the complete area of the optical fiber coating layer at the moment, and marking the length as L, wherein L is the effective coupling length in the current state;
(5) Starting weak light of a light source laser, and adjusting the positions of two bare fibers at the output end of the optical fiber and the positions of the corresponding power meters so that the center of a light spot coincides with the center of a photosensitive surface of the power meter;
(6) Starting a light source laser to preset power P, and recording the power meter reading P 'corresponding to the pumping fiber at the moment after the power meter reading is stable' 1 The corresponding power meter reading P 'of the signal fiber' 2 Then turning off the light source laser;
(7) Record data (L, P' 1 ，P' 2 ) Is a set of measurement data;
(8) At the fiber output end: breaking the coating layer with the length delta L at the junction of the complete part of the coating layer and the bare fiber, so that the pumping fiber and the signal fiber can be naturally separated in the delta L section;
(9) Recording the effective length L of the complete area of the optical fiber coating layer at the moment 1 ；
(10) Repeating the step (6), and recording the corresponding power data as P 'respectively' 1 ，P'' 2 ；
(11) At this time, data (L) 1 ，P'' 1 ，P'' 2 ) Obtaining a second set of data;
(12) Continuously repeating the steps (8) to (11) to obtain a plurality of groups of data, and drawing the data in a coordinate system with the effective coupling length z as an abscissa and the power P as an ordinate to obtain P 1 (z) and P 2 (z) distribution graph, P 1 (z)、P 2 (z) represents the pump power at the coordinate z in the inner cladding of the pump fiber and the signal fiber, respectively;
(13) According to P 1 (z) and P 2 (z) calculating the coupling coefficient k between the pump fiber and the signal fiber by combining the formula 1 And k 2 。
Preferably, in the step (1), the length of a bare fiber formed by removing coating layers from two ends of the optical fiber is 20-30 cm; in the step (5), the light spot size occupies 60% -80% of the area of the photosensitive surface.
Preferably, in the step (8), the length of DeltaL is 1-5 cm; in step (12), Δl is the same or different in any two measurements of the repeated operation.
The invention also provides a distributed side-pumped optical fiber coupling coefficient measurement system, which comprises a light source subsystem, an optical fiber processing system, a central control system, a first power detector and a second power detector, wherein the light source subsystem is used for outputting laser to a pump fiber at the input end of an optical fiber to be measured, the optical fiber processing system is used for carrying out cutting-off processing or separation processing on the optical fiber to be measured according to the effective coupling length of the optical fiber to be measured, the separation processing method is the processing method adopted in the distributed side-pumped optical fiber coupling coefficient measurement method, the first power detector and the second power detector are respectively used for detecting the power of the pump fiber and the signal fiber at the output end of the optical fiber, and the central control system is respectively connected with the light source subsystem, the optical fiber processing system, the first power detector and the second power detector and is used for data acquisition and analysis processing.
Preferably, the optical fiber processing system initially uses a cutting method to process the optical fiber with the length of L, the cutting step length is set to be L/10, and the detection data P of the first power detector and the second power detector are automatically acquired 1 And P 2 Calculating the ratio factor f=p of the two 1 /P 2 At f m ，f n ，f p The three ratio factor data obtained by measuring in sequence for three times in any succession are marked, and when one of the following arbitrary conditions is met:
i) Condition 1: effective coupling length L of optical fiber e < 0.3L；
ii) condition 2: f (f) p > f n >f m And f p - f m > 1.5f n ；
The optical fiber processing system is automatically switched to a separation method to separate and process the optical fibers in a small step length Deltal, wherein the small step length Deltal is set to be 1/10 of the effective coupling length of the current optical fibers, and when Deltal is the same as<At 5cm, then Δl is fixed to be 5cm; after the whole optical fiber is processed, the central control system automatically calculates the coupling coefficient k between the pumping fiber and the signal fiber through an internal preset calculation program 1 And k 2 。
The invention also provides a distributed side-pumped optical fiber coupling coefficient measuring device, which comprises a plurality of lasers, a laser driving power supply system, an optical fiber loading part, an optical fiber transmission guiding component, a coating layer destroying cutter, two coating layer removing components, a third power detector, a fourth power detector, a mechanical transmission control system and a control center, wherein the optical fiber loading part is used for loading an optical fiber to be measured, each laser is used for outputting laser to a pumping fiber of an input end of the optical fiber to be measured, the laser driving power supply system is used for controlling the output wavelength of each laser, the optical fiber transmission guiding component is used for transmitting and guiding the output end of the optical fiber to the coating layer destroying cutter, the mechanical transmission control system is used for controlling the operation of the optical fiber loading part and the optical fiber transmission guiding component, the coating layer destroying cutter is used for cutting a coating layer with the advancing length of the optical fiber, so that the pumping fiber is separated from a signal fiber, one of the coating layer removing components is used for removing the coating layer on the separated pumping fiber, cutting the output end of the pumping fiber, the third power detector is used for detecting the laser output power of the end face after the pumping fiber is cut, the other laser driving power detector is used for removing the laser power of the pumping fiber, the output end, the other laser driving power detector is used for detecting the power of the signal after the coating layer is cut, and the signal is cut by the laser power detector is used for cutting the signal and used for controlling the power of the laser power, which is connected with the fourth power detector.
Preferably, the optical fiber loading part is an optical fiber loading disc, the optical fiber transmission guiding assembly comprises a rotary wheel disc and two driving belt clamps, each driving belt clamp comprises two rollers and driving belts connected with the two rollers, the two driving belt clamps are respectively arranged on two sides of an optical fiber and used for clamping, conveying and guiding the optical fiber through the two driving belts, and the rotary wheel disc is arranged between the driving belt clamps and the optical fiber loading disc and used for conveying and guiding the optical fiber on the optical fiber loading disc between the two driving belt clamps.
Preferably, the coating layer removing assembly comprises two annular clamps and a cylindrical coating layer remover arranged between the two annular clamps; the annular clamp comprises an annular outer ring, a plurality of arc-shaped clamping pieces are uniformly arranged in the annular outer ring along the circumferential direction, one end, close to the center, of each arc-shaped clamping piece surrounds a clamping through hole, the clamping through holes are used for clamping an optical fiber to be processed, and the sizes of the clamping through holes can be adjusted by adjusting the arc-shaped clamping pieces; the cylindrical coating remover comprises an annular outer cylinder, an annular coating stripping knife and a cutting knife, wherein the annular coating stripping knife is axially arranged in the annular outer cylinder in a sliding manner, the annular coating stripping knife comprises a knife blade mounting annular ring, a plurality of arc-shaped blades are uniformly arranged in the knife blade mounting annular ring along the circumferential direction, one end, close to the center, of each arc-shaped blade is provided with an arc-shaped blade, each arc-shaped blade surrounds a stripping hole, and the size of the stripping hole can be adjusted by adjusting the arc-shaped blades; the cutting knife is arranged at one end, far away from the coating layer damage knife, in the annular outer cylinder, and the cutting knife is radially arranged along the annular outer cylinder and driven to radially move by the first telescopic driving device.
Preferably, the third power detector and the fourth power detector are respectively arranged at one side of the two coating layer cleaning components, which is far away from the coating layer breaking tool, and the third power detector and the fourth power detector are respectively connected with two second telescopic driving devices, and the third power detector and the fourth power detector can be driven by the second telescopic driving devices to move along the radial direction of the coating layer cleaning components so as to be aligned with the end face of the cut optical fiber; and one side of the third power detector and one side of the fourth power detector, which are far away from the coating layer cleaning assembly, are respectively provided with a waste fiber collecting box used for collecting the cut pump fiber waste fibers and the cut signal fiber waste fibers.
Preferably, the output end of each laser inputs laser to the pump fiber at the input end of the optical fiber to be tested through the optical fiber combiner; and the coating layer breaking cutter is provided with scale marks for measuring the optical fiber advancing length of the coating layer breaking area.
Compared with the prior art, the invention has the following technical effects:
the invention provides a novel separation method measurement method which is more practical, better in fault tolerance and higher in sensitivity based on a coupling theoretical model in DSCCP optical fibers, simultaneously combines a separation method and a cut-off method to provide a self-adaptive measurement system under different lengths, improves measurement precision, finally designs a measurement device capable of rapidly and automatically measuring coupling coefficients according to the system, has stronger adaptability and application value under various schemes, has feasibility and wide application prospect in engineering, solves the problem that the sampling points of measurement data in a severe change area are too small in the conventional method in actual measurement, can doubly improve the measurement data quantity of a transition area, improves the precision of a graph of power along with the length change, and improves the accuracy of measurement of the coupling coefficients.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic cross-sectional view of a conventional dual-clad gain fiber;
FIG. 2 is a schematic cross-sectional view of a (1+1) DSCCP optical fiber;
FIG. 3 is a schematic cross-sectional view of a (2+1) -type DSCCP optical fiber;
FIG. 4 is a schematic cross-sectional view of a (3+1) DSCCP optical fiber;
FIG. 5 is a schematic cross-sectional view of an (8+1) -type DSCCP optical fiber;
FIG. 6 is a schematic diagram of a (1+1) DSCCP optical fiber operating with a cut-off method;
FIG. 7 is a graph of power coupling of a pump fiber and a signal fiber;
FIG. 8 is a schematic diagram of a (1+1) DSCCP optical fiber operating with a split method;
FIG. 9 is a schematic diagram of a system for measuring coupling coefficient of a distributed side-pumped fiber according to the present invention;
FIG. 10 is a schematic diagram of a device for measuring coupling coefficient of a distributed side-pumped fiber according to the present invention;
FIG. 11 is a schematic side view of the ring clamp of the present invention;
FIG. 12 is a schematic elevational view of a barrel coating remover according to the present invention;
FIG. 13 is a schematic side view of a barrel coating layer remover according to the invention.
In the figure: 1-illuminant subsystem, 2-fiber processing system, 3-hub control system, 4-first power detector, 5-second power detector, 6-fiber, 7-first laser, 8-second laser, 9-third laser, 10-fiber combiner, 11-waste fiber collection box, 12-fiber loading tray, 13-rotating wheel disc, 14-laser drive power system, 15-mechanical drive control system, 16-control hub, 17-belt clamp, 1701-roller, 1702-belt, 18-coating break blade, 19-pump fiber, 20-signal fiber, 21-ring clamp, 2101-ring outer race, 2102-arcuate clamp blade, 2103-clamp through hole, 22-cylindrical coating cleaner, 2201-ring outer barrel, 2202-ring coating stripper blade, 22021-blade mounting ring, 22022-arcuate blade, 22023-arcuate blade, 22024-stripper hole, 2203-cutter, 23-third power detector, 24-fourth power detector.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
For convenience of description, the (1+1) -type DSCCP optical fiber having the simplest structure is described herein, but without loss of generality, all the inventive content is applicable to other types of (n+1) -type DSCCP optical fibers.
As shown in FIG. 8, the invention provides a method for measuring coupling coefficient of a distributed side-pumped fiber, which is characterized in that a small section of coating of the fiber is destroyed in measurement, so that two fibers can be naturally separated, the effective coupling length (i.e. the position z value) of the complete area of the coating is changed on the basis of unchanged physical length of the fiber, and a series of data is obtained through continuous operation, thus obtaining P 1 (z) and P 2 (z) distribution relationship.
The specific operation steps are as follows:
(1) Removing coating layers (about 20-30 cm) with certain lengths from two ends of the optical fiber to be measured, and cleaning the surface of the bare fiber;
(2) On the fiber injection end side: separating the pumping fiber from the signal fiber bare fiber without breaking, cutting the tail end of the pumping fiber into a flat angle by using a cutting knife, cutting the tail end of the output fiber of the matched light source laser into a flat angle, and welding the two through a welding machine; cutting the tail end of the signal fiber into an 8-degree oblique angle by using a cutting knife, and aligning the tail end surface of the signal fiber by using a light receiving cylinder to collect stray light;
(3) On the fiber output side: the method comprises the steps of separating a pumping fiber from a signal fiber bare fiber without breaking, cutting the tail end of the pumping fiber and the signal fiber bare fiber into 8-degree oblique angles by using a cutting knife, aligning the centers of photosensitive surfaces of the power meters to the end surfaces of respective optical fibers by using two power meters, and matching the measuring range of the power meters with the maximum output power of a light source laser;
(4) Measuring the length of the complete area of the optical fiber coating layer at the moment, and marking the length as L, wherein L is the effective coupling length in the current state;
(5) And starting weak light of the light source laser, and adjusting the positions of the two bare fibers at the output end of the optical fiber and the positions of the corresponding power meter to ensure that the center of a light spot coincides with the center of a photosensitive surface of the power meter, and simultaneously, the size of the light spot occupies about 60-80% of the area of the photosensitive surface.
(6) Starting a light source laser to preset power P, and recording the power meter reading P 'corresponding to the pumping fiber at the moment after the power meter reading is stable' 1 The corresponding power meter reading P 'of the signal fiber' 2 Then turning off the light source laser;
(7) Record data (L, P' 1 ，P' 2 ) Then a set of measurement data;
(8) At the output end of the optical fiber, the whole part of the coating layer and the juncture of the bare fiber are broken by a blade to remove a small section of the coating layer with the length delta L (delta L is typically 1-5 cm in length), so that the pumping fiber and the signal fiber are not tightly wrapped together in the delta L section, but can be slightly separated under the action of external force, and the coating slag on the surface of the optical fiber in the delta L section does not need to be cleaned;
(9) Recording the effective length L of the complete area of the optical fiber coating layer at the moment 1 Can pass through L 1 The value of the symbol L-delta L is calculated and can be measured;
(10) Repeating the step (6), and recording the corresponding power data as P 'respectively' 1 ，P'' 2 ；
(11) At this time, data (L) 1 ，P'' 1 ，P'' 2 ) A second set of data is obtained;
(12) Continuously repeating the steps (8) to (11), obtaining a plurality of groups of data, and drawing the data in a two-dimensional coordinate system with the effective coupling length z as an abscissa and the power P as a coordinate, thereby obtaining P 1 (z) and P 2 (z) distribution relation, P 1 (z)、P 2 (z) represents the pumping power at the position of z in the inner cladding of the pumping fiber and the signal fiber respectively, and ΔL can be the same or different in any two measurements of repeated operation;
(13) According to P 1 (z) and P 2 (z) distribution and calculation idea described herein, calculating the coupling coefficient k between the two 1 And k 2 。
As shown in fig. 9, the invention provides a distributed side-pumped fiber coupling coefficient measurement system, which is a system for comprehensively adopting a cutting-off method and a separating method for the same DSCCP fiber and adopting different methods in different areas so as to efficiently and quickly obtain measurement results.
The measuring system comprises a light source subsystem 1, an optical fiber processing system 2, a central control system 3, a first power detector 4 and a second power detector 5, wherein the light source subsystem is used for outputting laser to a pump fiber at the input end of an optical fiber 6 to be measured, the optical fiber processing system 2 is used for carrying out cutting-off processing or separation processing on the optical fiber 6 to be measured according to the effective coupling length of the optical fiber 6 to be measured, the separation processing is a processing method adopted in the distributed side pump optical fiber coupling coefficient measuring method, the first power detector 4 and the second power detector 5 are respectively used for detecting the power of the pump fiber and the signal fiber at the output end of the optical fiber 6, and the central control system 3 is respectively connected with the light source subsystem 1, the optical fiber processing system 2, the first power detector 4 and the second power detector 5 and is used for data acquisition and analysis processing.
The system principle is as follows, and it can be seen from FIG. 7 that when the DSCCP fiber effective coupling area is long, P 1 And P 2 The change rate is slow, the value is stable, the method is suitable for selecting a larger length, and the optical fiber is processed by a large step length by adopting a cutting method, so that a sampling point with a relatively stable tail value is rapidly obtained; when P is found 1 And P 2 Variation ofWhen the rate is accelerated, the separation method is automatically replaced to process the optical fiber, the dense sampling points of the exponentially-changed sections are accurately measured through small step sizes, and then the dense sampling points are combined to obtain the whole group of data points.
In a specific operation, the initial fiber processing system 2 processes the fiber 6 to be tested with a length L by default by adopting a cutting method, the cutting step length is set to be 1/10 of the length of the fiber, namely L/10, and the power P of the first power detector 4 is automatically measured 1 And the power P of the second power detector 5 2 Calculating the ratio factor f=p 1 /P 2 At f m ，f n ，f p The three ratio factor data obtained by sequentially measuring three times in any succession are marked. When any one of the following conditions is satisfied:
i) Condition 1: effective coupling length L of optical fiber e < 0.3L；
ii) condition 2: f (f) p > f n >f m And f p - f m > 1.5f n ；
The optical fiber processing system 2 automatically switches to a splitting method to split the optical fiber by a small step length Deltal, wherein the small step length Deltal is set to be 1/10 of the effective coupling length of the current optical fiber, and when Deltal is less than 5cm, deltal is fixed to be 5cm later.
The central control system 3 automatically calculates k through an internal preset calculation program after the whole optical fiber is processed 1 And k 2 。
10-13, based on the design of the measuring method and the measuring system, the invention provides an automatic continuous measuring device for the coupling coefficient, which has application value and operability, and the device visualizes the system, realizes the automatic continuous measurement of the DSCCP coupling coefficient, has less influence of human factors in the measuring process, and therefore, the measured result has higher reference significance.
The measuring device comprises a plurality of lasers, a laser driving power supply system 14, an optical fiber loading part, an optical fiber transmission guiding component, a coating layer destroying cutter 18, two coating layer destroying cutters 18, a third power detector 23, a fourth power detector 24, a mechanical transmission control system 15 and a control center 16, wherein three lasers are arranged in the embodiment, the three lasers are respectively a first laser 7, a second laser 8 and a third laser 9, the optical fiber loading part is used for loading an optical fiber 6 to be measured, each laser is used for outputting a pumping fiber of laser to an input end of the optical fiber 6 to be measured, the laser driving power supply system 14 is used for controlling output wavelength of each laser, the optical fiber transmission guiding component is used for transmitting an output end of the optical fiber 6 and guiding the output end of the optical fiber to the coating layer destroying cutter 18, the mechanical transmission control system 15 is used for controlling operation of the optical fiber loading part and the optical fiber transmission guiding component, the coating layer destroying cutter 18 is used for cutting a coating layer with the advancing length of the optical fiber 6, the pumping fiber is separated from the signal fiber, one coating layer destroying component is used for removing the coating layer on the separated pumping fiber 19, and cutting the output end of the pumping fiber 19, the third power detector 23 is used for detecting the end face of the optical fiber to be measured, each laser is used for outputting the laser power of the laser to the output end of the laser to the optical fiber 6 to be measured, the output end of the laser is used for outputting the laser signal after the laser power of the laser is used for cutting the signal 20 is used for cutting the signal after the laser is separated, the signal is used for detecting the signal 20 is cut, and the signal is used for controlling the output end of the signal 20 is used for cutting the laser 20 is used for controlling the end is connected to be cut and 20 is used for controlling the power and is used for respectively for controlling the power 20.
The optical fiber loading part is an optical fiber loading disc 12, the optical fiber transmission guiding component comprises a rotary wheel disc 13 and two transmission belt clamps 17, the transmission belt clamps 17 comprise two rollers 1701 and transmission belts 1702 connected with the two rollers 1701 in a transmission way, the two transmission belt clamps 17 are respectively arranged on two sides of the optical fiber 6 and used for clamping, conveying and guiding the optical fiber 6 through the two transmission belts 1702, the rotary wheel disc 13 is arranged between the transmission belt clamps 17 and the optical fiber loading disc 12 and used for conveying and guiding the optical fiber 6 on the optical fiber loading disc 12 between the two transmission belt clamps 17.
The coating layer removing assembly comprises two annular clamps 21 and a cylindrical coating layer remover 22 arranged between the two annular clamps 21; the annular clamp 21 comprises an annular outer ring 2101, a plurality of arc-shaped clamping pieces 2102 are uniformly arranged in the annular outer ring 2101 along the circumferential direction, one end, close to the center, of each arc-shaped clamping piece 2102 surrounds a clamping through hole 2103, the inside of the clamping through hole 2103 is used for clamping an optical fiber to be processed, and the size of the clamping through hole 2103 can be adjusted by adjusting the arc-shaped clamping pieces 2102; the cylindrical coating remover 22 comprises an annular outer cylinder 2201, an annular coating stripping knife 2202 and a cutting knife 2203, wherein the annular coating stripping knife 2202 is axially and slidably arranged in the annular outer cylinder 2201, the annular coating stripping knife 2202 comprises a blade mounting annular ring 22021, a plurality of arc blades 22022 are uniformly arranged in the blade mounting annular ring 22021 along the circumferential direction, one end, close to the center, of each arc blade 22022 is provided with an arc blade 22023, each arc blade 22023 surrounds a stripping hole 22024, and the size of the stripping hole 22024 can be adjusted by adjusting the arc blades 22022; the cutter 2203 is disposed at an end of the annular outer cylinder 2201 far away from the coating layer breaking cutter 18, and the cutter 2203 is disposed radially along the annular outer cylinder 2201 and is driven to move radially by the first telescopic driving device. Wherein the arcuate blade 22023 may be inclined toward the entrance end of the annular outer barrel 2201 to facilitate stripping of the coating layer outside the optical fiber 6. The connection structure between the annular outer ring 2101 and the arc clamping piece 2102, and the mounting structure between the blade mounting annular ring 22021 and the arc blade 22022 are the same as the structure of the adjustable diaphragm, and belong to the prior art, and the connection structure is not described in detail here.
The third power detector 23 and the fourth power detector 24 are respectively arranged on one side of the two coating layer cleaning assemblies, which is far away from the coating layer breaking cutter 18, and the third power detector 23 and the fourth power detector 24 are respectively connected with two second telescopic driving devices, and the third power detector 23 and the fourth power detector 24 can be driven by the second telescopic driving devices to move along the radial direction of the coating layer cleaning assemblies so as to align the end faces of the cut optical fibers; the third power detector 23 and the fourth power detector 24 are respectively provided with a waste fiber collecting box 11 at one side far away from the coating layer cleaning assembly, and are respectively used for collecting the cut pump fiber waste fibers and the signal fiber waste fibers.
The output end of each laser inputs laser to the pump fiber at the input end of the optical fiber 6 to be tested through the optical fiber combiner 10; graduation marks are provided on the coating-breaking cutter 18 for measuring the optical fiber advancing length of the coating-breaking region.
The laser in the invention can be selected from gas laser, liquid laser, solid laser and the like; the optical fiber combiner 10 can be changed into other numbers or types of combiners (such as 7×1, (6+1) ×1, etc.) according to practical situations, or the laser output end and the pump fiber are directly welded together without arranging the combiner 4; the control center 16 may select a device such as a server or a single-chip microcomputer having control and data acquisition functions.
The device components and their respective functions illustrated in fig. 10 are as follows:
the control center 16 (a computer in this embodiment) controls the laser driving power system 14 to transmit a specific current to the first laser 7, the second laser 8 and the third laser 9, and the first laser 7, the second laser 8 and the third laser 9 output lasers to enter the pumping fiber of the dscp optical fiber to be tested through the optical fiber combiner 10, and the end face of the other signal fiber 20 of the dscp optical fiber is beveled. The output wavelengths of the first laser 7, the second laser 8 and the third laser 9 are respectively lambda 1 、λ 2 、λ 3 When lambda is 1 ≠λ 2 ≠λ 3 The coupling efficiency at different wavelengths can be tested when lambda 1 =λ 2 =λ 3 Then a single wavelength lambda can be tested 1 Lower coupling efficiency.
The DSCCP optical fiber to be measured with a longer distance is coiled on the peripheral part of the optical fiber loading disc 12, one end of the DSCCP optical fiber is led out from the inner side, the pumping fiber is connected to the optical fiber combiner 10, the signal fiber 20 is cut to form an oblique angle end face, and the other end of the signal fiber is coiled on the rotating wheel disc 13 and is clamped and driven by the two transmission belt type clamps 17. The control center 16 controls the mechanical transmission control system 15 such that the optical fiber loading tray 12, the rotating wheel tray 13 and the two belt clamps 17 are all rotated at a constant speed of a linear velocity v (adjustable) for a time t, and the DSCCP optical fiber is driven to advance forward along the x-axis at a speed v by a distance l=vt, and at the same time the coating layer breaking cutter 18 cuts the coating layer corresponding to the advancing length L so that the pump fiber 19 is separated from the signal fiber 20 and enters the subsequent processing and testing section, respectively. The coating layer breaking tool 18 is provided with a scale, and the length of the coating layer breaking area can be accurately measured.
As shown in fig. 10, the ring clamp 21 has a thickness in the x-axis direction and has an adjustable-size clamping through hole 2103 at the center thereof, the size of the clamping through hole 2103 is adjustable by the inner arc-shaped clamping piece 2102, and the optical fiber is clamped against movement in the x-axis direction by adjusting the size of the clamping through hole 2103. The front and side schematic views of the cylindrical coating layer remover 22 are shown in fig. 12 and 13, and a movable annular coating layer stripping knife 2202 is disposed inside the annular outer cylinder 2201, which is similar in principle to the annular jig 21 in fig. 11, but is different in that the inner side thereof is a sharp blade. The side is as shown in fig. 13, after an optical fiber passes through the center of the annular outer cylinder 2201, the inner ring size of the annular coating stripping knife 2202 is adjusted to be matched with the diameter of the optical fiber after the coating is removed, a guide rail along the x-axis direction is arranged in the annular outer cylinder 2201, and the annular coating stripping knife 2202 moves back and forth on the guide rail to remove the coating of part of the optical fiber in the annular outer cylinder 2201 completely. On the side of the annular outer cylinder 2201 in the positive x-axis direction, a cutter 2203 is provided which can move in the y-axis direction (radial direction), when the optical fiber coating is cleaned, the cutter 2203 is extended to cut the optical fiber, the cut short length waste fiber automatically falls into the waste fiber collecting box 11, and the power detectors (the third power detector 23 and the fourth power detector 24) which can move in the y-axis direction (radial direction) extend out, and the center of the detection surface is aligned with the end face of the cut optical fiber for measuring the output laser power. The automatic processing and data acquisition of the whole system is controlled by the control center 16 in a unified way.
The use flow of the measuring device is specifically as follows:
1. first, an optical fiber disk around which a dscp optical fiber is wound is loaded on the optical fiber loading disk 12, one end coating layer is broken and used as an input end, the input end is led out from the center of the optical fiber loading disk 12, and an input end pumping fiber is fused with the optical fiber combiner 10, and a signal fiber is cut into an oblique angle. The other end of the optical fiber sequentially passes through the rotary wheel disc 13 and the two transmission belt clamps 17, and the coating is removed by a certain distance through the coating destroying cutter 18 and then is separated into a signal fiber 20 and a pump fiber 19, wherein the signal fiber 20 penetrates into one coating removing assembly, and the pump fiber 19 penetrates into the other coating removing assembly.
2. The control center 16 controls the annular coating stripping knives in the two cylindrical coating removers 22 to remove the coating layers of the signal fiber 20 and the pumping fiber 19 in the annular outer cylinder 2201, the control center 16 controls the two cutting knives 2203 to extend after the coating layers are completed, the signal fiber 20 and the pumping fiber 19 are cut off to obtain cutting end surfaces, and the waste fiber is collected by the two waste fiber collecting boxes 11.
3. The control center 16 controls the third power detector 23 and the fourth power detector 24 to extend to be respectively aligned with the centers of the cutting surfaces, and simultaneously controls the laser driving power supply system 14 to supply power to the pump source, and records the length L of the optical fiber and the indication P of the third power detector 23 at the moment 1 And the power indication P of the fourth power detector 24 2 To obtain a set of measurement data (L, P 1 ，P 2 ) The third power detector 23 and the fourth power detector 24 are then retracted.
4. The control center 16 controls the optical fiber loading disc 12, the rotary wheel disc 13 and the transmission belt type clamp 17 to rotate at a constant speed for a forward distance m, and at the moment, the optical fiber coating layer at the position of the coating layer breaking cutter 18, which is a distance m, is broken, and the optical fibers are separated. The cut sections of the separated pumping fibers 19 and signal fibers 20 are also advanced by a distance m to the upper sections of the two waste fiber collecting boxes 11, respectively.
5. Step 3 is repeated, recording the fiber length L '(where L' =l-m) at this time, and the power indication P 'of the fourth power detector 24' 2 And a power indication P 'of the third power detector 23' 1 Obtaining a second set of measurement data (L ', P' 1 ，P' 2 ）
6. And (5) repeating the steps 4-5 to obtain a series of data sets, and automatically storing the data sets by a computer.
7. In the testing process, the computer automatically draws the obtained data into a coupling coefficient data diagram in FIG. 7 in real time, and automatically calculates the corresponding coupling coefficient k after the testing is finished 1 And k 2 。
When the coupling coefficients of different wavelengths need to be tested, only the computer-controlled laser driving power system 14 is needed to load current to the lasers (lambda) of different wavelengths 1 ≠λ 2 ≠λ 3 ) And (5) emitting laser to repeat the measuring process.
The device realizes automatic measurement through an automatic control device by measuring complex data points, achieves the aim of simplifying the flow and rapidly processing, and can realize automatic processing through a preset program in a control computer no matter the device adopts a cutting method, a separation method or a measuring system combining the cutting method and the separation method. Meanwhile, compared with manual measurement in the automatic process, the method greatly reduces the manual quantity, reduces the interference of human factors on the measurement result, and keeps the consistency of the measurement result of the coupling coefficient under the same condition.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (10)
1. The method for measuring the coupling coefficient of the distributed side pumping optical fiber is characterized by comprising the following steps of:
(1) Removing coating layers from two ends of the optical fiber, and cleaning the surfaces of bare fibers at two ends;
(2) On the fiber injection end side: separating the pumping fiber from the signal fiber bare fiber, cutting the tail end of the pumping fiber into a flat angle, cutting the tail end of the output fiber of the matched light source laser into a flat angle, then welding the tail end of the matched light source laser with the tail end of the pumping fiber, cutting the tail end of the signal fiber into an oblique angle, and aligning the tail end face of the signal fiber with a light receiving cylinder to collect stray light;
(3) On the fiber output side: dividing a pumping fiber and a signal fiber bare fiber, respectively cutting the tail ends of the two bare fibers into oblique angles, respectively aligning the centers of photosensitive surfaces of the two power meters with the end surfaces of the pumping fiber and the signal fiber bare fiber, wherein the measuring range of the power meters is matched with the maximum output power of a light source laser;
(4) Measuring the length of the complete area of the optical fiber coating layer at the moment, and marking the length as L, wherein L is the effective coupling length in the current state;
(5) Starting weak light of a light source laser, and adjusting the positions of two bare fibers at the output end of the optical fiber and the positions of the corresponding power meters so that the center of a light spot coincides with the center of a photosensitive surface of the power meter;
(6) Starting a light source laser to preset power P, and recording the power meter reading P 'corresponding to the pumping fiber at the moment after the power meter reading is stable' 1 The corresponding power meter reading P 'of the signal fiber' 2 Then turning off the light source laser;
(7) Record data (L, P' 1 ，P' 2 ) Is a set of measurement data;
(8) At the fiber output end: breaking the coating layer with the length delta L at the junction of the complete part of the coating layer and the bare fiber, so that the pumping fiber and the signal fiber can be naturally separated in the delta L section;
(9) Recording the effective length L of the complete area of the optical fiber coating layer at the moment 1 ；
(10) Repeating the step (6), and recording the corresponding power data as P 'respectively' 1 ，P'' 2 ；
(11) At this time, data (L) 1 ，P'' 1 ，P'' 2 ) Obtaining a second set of data;
(12) Continuously repeating the steps (8) to (11) to obtain a plurality of groups of data, and drawing the data in a coordinate system with the effective coupling length z as an abscissa and the power P as an ordinate to obtain P 1 (z) and P 2 (z) distribution graph, P 1 (z)、P 2 (z) represents the pump power at the coordinate z in the inner cladding of the pump fiber and the signal fiber, respectively;
(13) According to P 1 (z) and P 2 (z) calculating the coupling coefficient k between the pump fiber and the signal fiber by combining the formula 1 And k 2 。
2. The method for measuring the coupling coefficient of the distributed side-pumped fiber according to claim 1, wherein: in the step (1), the length of a bare fiber formed by removing coating layers at two ends of an optical fiber is 20-30 cm; in the step (5), the light spot size occupies 60% -80% of the area of the photosensitive surface.
3. The method for measuring the coupling coefficient of the distributed side-pumped fiber according to claim 1, wherein: in the step (8), the length of delta L is 1-5 cm; in step (12), Δl is the same or different in any two measurements of the repeated operation.
4. The utility model provides a distributed side pumping optic fibre coupling coefficient measurement system which characterized in that: the method comprises a light source subsystem, an optical fiber processing system, a central control system, a first power detector and a second power detector, wherein the light source subsystem is used for outputting laser to a pumping fiber at an input end of an optical fiber to be detected, the optical fiber processing system is used for carrying out cutting-off processing or separation processing on the optical fiber to be detected according to the effective coupling length of the optical fiber to be detected, the separation method is a processing method adopted in the distributed side pumping optical fiber coupling coefficient measuring method according to any one of claims 1-3, the first power detector and the second power detector are respectively used for detecting the power of the pumping fiber at the output end of the optical fiber and the power of a signal fiber, and the central control system is respectively connected with the light source subsystem, the optical fiber processing system, the first power detector and the second power detector and is used for data acquisition and analysis processing.
5. The distributed side-pumped fiber coupling coefficient measurement system of claim 4, wherein: the optical fiber processing system initially adopts a cutting method to process the optical fiber with the length of L, the cutting step length is set to be L/10, and the detection data P of the first power detector and the second power detector are automatically obtained 1 And P 2 Calculating the ratio factor f=p of the two 1 /P 2 At f m ，f n ，f p The three ratio factor data obtained by measuring in sequence for three times in any succession are marked, and when one of the following arbitrary conditions is met:
i) Condition 1: effective coupling length L of optical fiber e < 0.3L；
ii) condition 2: f (f) p > f n >f m And f p - f m > 1.5f n ；
The optical fiber processing system is automatically switched to a separation method to separate and process the optical fibers in a small step length Deltal, wherein the small step length Deltal is set to be 1/10 of the effective coupling length of the current optical fibers, and when Deltal is the same as<At 5cm, then Δl is fixed to be 5cm; after the whole optical fiber is processed, the central control system automatically calculates the coupling coefficient k between the pumping fiber and the signal fiber through an internal preset calculation program 1 And k 2 。
6. The utility model provides a distributed side pumping optic fibre coupling coefficient measuring device which characterized in that: the laser device comprises a plurality of lasers, a laser driving power supply system, an optical fiber loading part, an optical fiber transmission guiding component, a coating layer destroying cutter, two coating layer destroying cutters, a third power detector, a fourth power detector, a mechanical transmission control system and a control center, wherein the optical fiber loading part is used for loading an optical fiber to be detected, each laser is used for outputting laser to a pumping fiber of an input end of the optical fiber to be detected, the laser driving power supply system is used for controlling output wavelength of each laser, the optical fiber transmission guiding component is used for transmitting and guiding an output end of the optical fiber to the coating layer destroying cutter, the mechanical transmission control system is used for controlling operation of the optical fiber loading part and the optical fiber transmission guiding component, the coating layer destroying cutter is used for cutting a coating layer with the advancing length of the optical fiber to separate the pumping fiber from the signal fiber, one coating layer removing component is used for removing the coating layer on the separated pumping fiber, cutting the output end of the pumping fiber, the third power detector is used for detecting laser output power of an end face after the pumping fiber is cut, the other coating layer removing component is used for removing the coating layer on the separated signal fiber, and cutting the output end of the signal is cut, and the fourth power detector is used for detecting the output power of the laser power of the separated signal fiber, and the laser driving system is used for controlling the laser device to cut the power controller.
7. The distributed side-pumped fiber coupling coefficient measurement apparatus of claim 6, wherein: the optical fiber loading part is an optical fiber loading disc, the optical fiber transmission guide assembly comprises a rotary wheel disc and two transmission belt type clamps, each transmission belt type clamp comprises two idler wheels and transmission belts connected with the two idler wheels, the two transmission belt type clamps are respectively arranged on two sides of an optical fiber and used for clamping, conveying and guiding the optical fiber through the two transmission belts, and the rotary wheel disc is arranged between the transmission belt type clamps and the optical fiber loading disc and used for conveying and guiding the optical fiber on the optical fiber loading disc between the two transmission belt type clamps.
8. The distributed side-pumped fiber coupling coefficient measurement apparatus of claim 6, wherein: the coating layer cleaning assembly comprises two annular clamps and a cylindrical coating layer cleaner arranged between the two annular clamps; the annular clamp comprises an annular outer ring, a plurality of arc-shaped clamping pieces are uniformly arranged in the annular outer ring along the circumferential direction, one end, close to the center, of each arc-shaped clamping piece surrounds a clamping through hole, the clamping through holes are used for clamping an optical fiber to be processed, and the sizes of the clamping through holes can be adjusted by adjusting the arc-shaped clamping pieces; the cylindrical coating remover comprises an annular outer cylinder, an annular coating stripping knife and a cutting knife, wherein the annular coating stripping knife is axially arranged in the annular outer cylinder in a sliding manner, the annular coating stripping knife comprises a knife blade mounting annular ring, a plurality of arc-shaped blades are uniformly arranged in the knife blade mounting annular ring along the circumferential direction, one end, close to the center, of each arc-shaped blade is provided with an arc-shaped blade, each arc-shaped blade surrounds a stripping hole, and the size of the stripping hole can be adjusted by adjusting the arc-shaped blades; the cutting knife is arranged at one end, far away from the coating layer damage knife, in the annular outer cylinder, and the cutting knife is radially arranged along the annular outer cylinder and driven to radially move by the first telescopic driving device.
9. The distributed side-pumped fiber coupling coefficient measurement apparatus of claim 8, wherein: the third power detector and the fourth power detector are respectively arranged at one side of the two coating layer cleaning assemblies far away from the coating layer breaking cutter, the third power detector and the fourth power detector are respectively connected with two second telescopic driving devices, and the third power detector and the fourth power detector can be driven by the second telescopic driving devices to move along the radial direction of the coating layer cleaning assemblies so as to be aligned with the end face of the cut optical fiber; and one side of the third power detector and one side of the fourth power detector, which are far away from the coating layer cleaning assembly, are respectively provided with a waste fiber collecting box used for collecting the cut pump fiber waste fibers and the cut signal fiber waste fibers.
10. The distributed side-pumped fiber coupling coefficient measurement apparatus of claim 6, wherein: the output end of each laser inputs laser to the pumping fiber of the input end of the optical fiber to be tested through the optical fiber combiner; and the coating layer breaking cutter is provided with scale marks for measuring the optical fiber advancing length of the coating layer breaking area.
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