Optical fiber connection status determination system and optical fiber connection status determination method

Abstract

An optical fiber connection state assessment system that assesses the connection state of a first optical fiber through which a test light inputted from a light source is propagated, and a second optical fiber to which is inputted the test light propagated through the first optical fiber and outputted from the first optical fiber, in a connection part that detachably connects an output side of the first optical fiber, from which the test light is outputted, and an input side of the second optical fiber, wherein the system comprises a measurement unit for measuring the intensity of reflected light reflected in the test light and propagated through the first optical fiber, and an assessment unit for assessing the connection state of the first optical fiber and the second optical fiber in the connection part on the basis of the intensity measured by the measurement unit.

Description

[Technical field]

[0001] The present invention relates to a system and a method for determining the connection status of an optical fiber. [Background technology]

[0002] Examples of inventions for determining whether an optical fiber is broken include those disclosed in Patent Documents 1 to 3. The invention disclosed in Patent Document 1 has a configuration for detecting a break in an optical fiber by an electrical configuration. The invention disclosed in Patent Document 2 receives light reflected at the tip of the optical fiber and detects an abnormality in the optical fiber based on the difference between the light received when the optical fiber is not broken. The invention disclosed in Patent Document 3 receives light reflected and returned by the optical fiber with a light receiving sensor and detects an abnormality in the optical fiber by comparing the light reception result with a reference value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-224898 A [Patent Document 2] JP 2016-071040 A [Patent Document 3] JP 2002-291764 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a device for treating a patient using laser light, a laser device that outputs laser light is connected to a catheter inserted into the body for each surgery, and the laser light is output from the catheter to perform treatment. Since the laser device and the catheter are connected for each surgery, the laser device and the catheter are configured to be detachable. If the connection of the optical fiber between the catheter and the laser device is incomplete when the catheter is connected to the laser device, for example, the power of the laser light that reaches the affected area may be insufficient. For this reason, a technology for detecting the connection state of the optical fiber that propagates the laser light is desired.

[0005] Patent Document 1 discloses detecting disconnections, but does not disclose detecting connection defects. Patent Document 2 discloses detecting abnormalities in optical fibers, but does not disclose determining whether a connection is poor, and the invention of Patent Document 2 cannot detect connection defects. Patent Document 3 discloses detecting abnormalities due to bends or dirt on the end face, but does not disclose determining whether a connection is poor, and the invention of Patent Document 2 cannot detect connection defects either.

[0006] The present invention has been made in view of the above, and has an object to provide a technique for determining the connection state of a detachable optical fiber. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, an optical fiber connection status determination system according to one embodiment of the present invention is a system for determining the connection status of a first optical fiber and a second optical fiber at a connection section that detachably connects an output side of a first optical fiber that propagates test light input from a light source, where the test light is output, and an input side of a second optical fiber to which the test light propagated by the first optical fiber and output from the first optical fiber is input, and is characterized in comprising: a measurement unit that measures the intensity of reflected light that is reflected from the test light and propagates through the first optical fiber, and a determination unit that determines the connection status of the first optical fiber and the second optical fiber at the connection section based on the intensity measured by the measurement unit.

[0008] An optical fiber connection status determination system according to one embodiment of the present invention may be configured so that the intensity of the reflected light measured by the measurement unit differs between when the second optical fiber is broken and when the second optical fiber is detached from the connection unit.

[0009] An optical fiber connection status determination system according to one embodiment of the present invention may be configured such that the intensity of the reflected light measured by the measurement unit when the second optical fiber is broken is greater than the intensity of the reflected light measured by the measurement unit when the second optical fiber is detached from the connection portion.

[0010] An optical fiber connection status determination system according to one embodiment of the present invention is characterized in that the first optical fiber and the second optical fiber are spatially coupled at the connection portion, and the determination unit determines that the first optical fiber and the second optical fiber are poorly connected if the intensity is less than a first threshold value.

[0011] In an optical fiber connection status determination system according to one embodiment of the present invention, the second optical fiber may be configured to be connected to an optical fiber coupler, and the test light emitted from a predetermined port among a plurality of ports from which the test light is emitted in the optical fiber coupler may be reflected by a reflecting section that reflects the test light.

[0012] An optical fiber connection status determination system according to one embodiment of the present invention is characterized in that the measurement unit performs a measurement each time an operator performs a measurement, and the determination unit determines the connection status each time the measurement unit performs a measurement, and if the determination result is consecutively a connection failure, determines that the second optical fiber is broken.

[0013] In an optical fiber connection status determination system according to one embodiment of the present invention, the intensity of the reflected light measured by the measurement unit when the second optical fiber is detached from the connection portion may be greater than the intensity of the reflected light measured by the measurement unit when the second optical fiber is broken.

[0014] An optical fiber connection status determination system according to one embodiment of the present invention is characterized in that the first optical fiber and the second optical fiber are butt-spliced ​​at the connection portion, and the determination unit determines that the first optical fiber and the second optical fiber are poorly connected if the strength is greater than or equal to a second threshold and less than or equal to a third threshold that is greater than the second threshold.

[0015] In the optical fiber connection state determination system according to an aspect of the present invention, an optical fiber coupler may be connected to the second optical fiber.

[0016] An optical fiber connection status determination system according to one embodiment of the present invention is characterized in that the determination unit determines that the second optical fiber is broken when the strength is equal to or less than a fourth threshold value that is smaller than the second threshold value.

[0017] An optical fiber connection status determination system according to one aspect of the present invention is characterized in that it includes a notification unit that notifies the connection status of the first optical fiber and the second optical fiber in accordance with a determination result of the determination unit.

[0018] A system for determining the connection status of an optical fiber according to one embodiment of the present invention is characterized in that laser light for cauterizing a human body is combined with the test light and input to the first optical fiber, and when the determination unit determines that the second optical fiber is broken, the output of the laser light from a light source that outputs the laser light is stopped.

[0019] A method for determining a connection status of optical fibers according to one embodiment of the present invention is a method for determining a connection status of a first optical fiber and a second optical fiber at a connection section in which an output side of a first optical fiber that propagates test light input from a light source, from which the test light is output, and an input side of a second optical fiber to which the test light propagated by the first optical fiber and output from the first optical fiber is input, in a detachable manner, and is characterized in that it includes a measurement step of measuring an intensity of reflected light that is reflected from the test light and propagates through the first optical fiber, and a judgment step of judging the connection status of the first optical fiber and the second optical fiber based on the intensity measured in the measurement step. Effect of the Invention

[0020] According to the present invention, it is possible to determine the connection state of a detachable optical fiber. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a laser system according to the first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a functional configuration according to the first embodiment. [Diagram 3] FIG. 3 is a schematic diagram showing an example of a connection state of optical fibers at a connection portion. [Figure 4] FIG. 4 is a schematic diagram showing an example of a connection state of optical fibers at a connection portion. [Diagram 5] FIG. 5 is a schematic diagram showing an example of a connection state of optical fibers at a connection portion. [Figure 6] FIG. 6 is a flowchart showing the flow of the connection state determination process. [Figure 7] FIG. 7 is a schematic diagram showing an example of a connection state of optical fibers at a connection portion. [Figure 8] FIG. 8 is a schematic diagram showing an example of a connection state of optical fibers at a connection portion. [Figure 9] FIG. 9 is a schematic diagram showing an example of a connection state of optical fibers at a connection portion. [Figure 10] FIG. 10 is a flowchart showing the flow of the connection state determination process. [Figure 11] FIG. 11 is a diagram showing the configuration of a catheter according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] [First embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below. In addition, in the description of the drawings, the same or corresponding elements are appropriately designated by the same reference numerals.

[0023] 1 is a schematic diagram showing a schematic configuration of a laser system 1 according to a first embodiment of the present invention. The laser system 1 is a system for treating a patient by irradiating the patient with laser light. The laser system 1 includes a laser device 10 that outputs laser light to be irradiated to the patient, a connection unit 20 that connects the laser device 10 and a catheter 30, and the catheter 30 that irradiates the laser light to an affected area of ​​the patient.

[0024] In this embodiment, the laser device 10 includes a first laser diode 301, a second laser diode 302, and a photodiode 401. The laser device 10 also includes a multiplexer 501, a filter 601, an optical multiplexer / demultiplexer 701, and a first optical fiber 81a. The laser device 10 also includes a control unit 100, a display unit 200, and an operated unit 801. The laser device 10 is an example of a connection state determination system.

[0025] The first laser diode 301 is a light source that outputs a laser beam to be irradiated onto the affected area of ​​the patient. In the following description, the laser beam output from the first laser diode 301 is referred to as therapeutic light. In this embodiment, the therapeutic light has a wavelength in the near-infrared band, for example, within the range of 600 nm to 1500 nm. The therapeutic light output from the first laser diode 301 enters the multiplexer 501 via an optical fiber. The light source that outputs the therapeutic light is not limited to a laser diode and may be, for example, a fiber laser.

[0026] The second laser diode 302 is a light source that outputs a laser light used to determine the connection state of the two optical fibers connected at the connection part 20 and the state of the optical fiber provided in the catheter 30. In the following description, the laser light output from the second laser diode 302 is referred to as test light. The wavelength of the test light in this embodiment is 635 nm, but is not limited to 635 nm and may be other wavelengths. The test light output from the second laser diode 302 is incident on the multiplexer 501 via the optical fiber. The light source that outputs the test light is not limited to a laser diode.

[0027] The multiplexer 501 has a function of multiplexing multiple light beams with different wavelengths. The multiplexer 501 multiplexes the therapeutic light and test light that are input via an optical fiber, and outputs the therapeutic light and test light to the optical multiplexer / demultiplexer 701 via the optical fiber.

[0028] The optical multiplexer / demultiplexer 701 outputs the therapeutic light and test light input from the multiplexer 501 through the optical fiber to the first optical fiber 81a through the optical fiber. The therapeutic light and test light output from the optical multiplexer / demultiplexer 701 propagate through the first optical fiber 81. The optical multiplexer / demultiplexer 701 also outputs reflected light, which is a laser beam that has been reflected from the test light output to the first optical fiber 81a and propagated to the optical multiplexer / demultiplexer 701, to the filter 601 through the optical fiber. The optical multiplexer / demultiplexer 701 is preferably configured as a 50:50 TAP coupler, an asymmetric TAP coupler, a WDM coupler, or an appropriate combination of these.

[0029] The first optical fiber 81a is an optical fiber that propagates the treatment light and the test light. The first optical fiber 81a is connected to a second optical fiber 31a provided in a catheter 30 (described later) via a connection part 20. The first optical fiber 81a is, for example, a step-index type or a graded-index type multimode optical fiber, but is not limited thereto.

[0030] The filter 601 transmits light of a predetermined wavelength out of the reflected light that enters the filter 601. As a result, out of the reflected light that enters the filter 601, the laser light having the wavelength of the treatment light is blocked by the filter 601, and the laser light having the wavelength of the test light is transmitted through the filter 601. The reflected light that has passed through the filter 601 enters the photodiode 401.

[0031] The photodiode 401 is a photodetector that receives reflected light that has passed through the filter 601 and outputs a current signal according to the intensity of the received reflected light. The current signal output from the photodiode 401 is input to the control unit 100.

[0032] The display unit 200 is a liquid crystal display, and displays, for example, various information about the laser device 10, the connection state of the optical fiber in the connection unit 20, and the state of the optical fiber in the catheter 30, using characters, symbols, images, etc. The operated unit 801 includes buttons for operating the laser device 10. The operated unit 801 includes a button for switching between outputting and stopping the therapeutic light, and a button for starting a process for determining the connection state of the optical fiber in the connection in the connection unit 20. Note that the operated unit 801 is not limited to a button, and may be, for example, a touch panel, as long as it accepts operations by the operator of the laser device 10.

[0033] The control unit 100 includes a calculation unit and a storage unit. The calculation unit controls the first laser diode 301, the second laser diode 302, and the display unit 200, and performs various calculation processes for implementing the functions of the laser device 10. The control unit 100 is configured, for example, with a CPU (Central Processing Unit) or an FPGA (field-programmable gate array), or both a CPU and an FPGA.

[0034] The storage unit includes, for example, a portion configured with ROM (Read Only Memory) and a portion configured with RAM (Random Access Memory). The portion configured with ROM stores various programs and data used by the calculation unit to perform calculation processing. The RAM is used as a working space when the calculation unit performs calculation processing and to store the results of the calculation processing of the calculation unit.

[0035] 2 is a block diagram showing a functional configuration according to the embodiment among the functions realized by the calculation unit executing a program stored in the storage unit. The measurement unit 1001 acquires a current signal output from the photodiode 401. The measurement unit 1001 measures the intensity of reflected light incident on the photodiode 401 based on the acquired current signal.

[0036] The determination unit 1002 determines the connection state of the two optical fibers connected at the connection unit 20 based on the strength measured by the measurement unit 1001. The determination unit 1002 also determines whether the optical fiber provided in the catheter 30 is broken based on the strength measured by the measurement unit 1001.

[0037] The notification unit 1003 controls the display unit 200 so that the result of the determination by the determination unit 1002 is displayed on the display unit 200. In this way, the connection state of the two optical fibers connected at the connection unit 20 and the state of the optical fiber provided in the catheter 30 that propagates the therapeutic light are notified to the user of the laser device 10.

[0038] The light source control unit 1004 controls the first laser diode 301 and the second laser diode 302 based on the operation performed by the operated unit 801 and the determination result of the determination unit 1002. When the light source control unit 1004 outputs a drive signal for driving the first laser diode 301 to the first laser diode 301, the first laser diode 301 outputs therapeutic light, and when the light source control unit 1004 stops outputting the drive signal to the first laser diode 301, the first laser diode 301 stops outputting therapeutic light. When the light source control unit 1004 outputs a drive signal for driving the second laser diode 302 to the second laser diode 302, the second laser diode 302 outputs test light, and when the light source control unit 1004 stops outputting the drive signal to the second laser diode 302, the second laser diode 302 stops outputting test light.

[0039] 1, at least a portion of the catheter 30 is inserted into the patient's body, and irradiates the treatment area of ​​the patient with therapeutic light incident from the first optical fiber 81a via the connection part 20. The catheter 30 includes a catheter body 33 made of a flexible material such as resin, a second optical fiber 31a at least a portion of which is inserted into the lumen of the catheter body 33, and a fiber Bragg grating (FBG) 32. The catheter 30 is disposable for each surgery, is connected to the connection part 20 before the start of the surgery, and is removed from the connection part 20 after the surgery.

[0040] The second optical fiber 31a is, for example, a step-index or graded-index multimode optical fiber, but is not limited thereto. When the catheter 30 is inserted into a blood vessel, the second optical fiber 31a preferably has a small diameter, for example, a core diameter of 120 μm or less and a cladding diameter of 140 μm or less. Note that these core and cladding diameters are merely examples, and the second optical fiber 31a is not limited to these diameters. The end of the second optical fiber 31a at the connection portion 20 where the therapeutic light is incident is referred to as the incident end, and the end from which the therapeutic light is emitted is referred to as the exit end.

[0041] The FBG 32 is provided on the output end side of the second optical fiber 31a, and is fusion-spliced ​​to the output end of the second optical fiber 31a, for example. The FBG 32 transmits the therapeutic light that is incident on the input end of the second optical fiber 31a and propagates through the second optical fiber 31a. As a result, the therapeutic light is output from the tip of the second optical fiber 31a (the tip side of the catheter 30). The FBG 32 also reflects the test light that is incident on the input end of the second optical fiber 31a and propagates through the second optical fiber 31a. The reflectance of the test light in the FBG 32 is preferably 90% or more. If the reflectance of the test light in the FBG 32 is 90% or more, the test light can be efficiently reflected.

[0042] The connection unit 20 is a beam expanding connector that detachably connects an output side of the first optical fiber 81a, from which the therapeutic light and the output light are output, to an input side of the second optical fiber 31a, to which the therapeutic light and the output light are input. In the connection unit 20, the first optical fiber 81a and the second optical fiber 32a are connected, for example, by spatial coupling.

[0043] FIG. 3 is a schematic diagram showing an example of a connection state of optical fibers in the connection unit 20. The connection unit 20 includes a connector housing 22a and a connector housing 22b. The connector housing 22a and the connector housing 22b are male and female, respectively, and fit together. The ferrule 21a is fixed in the connector housing 22a and fixes an end of the first optical fiber 81a. The first lens LE1 is a convex lens that collimates and focuses the laser light, and is fixed in the connector housing 22a. The first lens LE1 collimates the laser light emitted from the first optical fiber 81a. The laser light collimated by the first lens LE1 is incident on the second lens LE2. The first lens LE1 also focuses the laser light incident from the second lens LE2 side. The laser light focused by the first lens LE1 is incident on the first optical fiber 81a.

[0044] The ferrule 21b is fixed in the connector housing 22b and fixes the end of the second optical fiber 31a. The second lens LE2 is a convex lens that collimates and focuses the laser light, and is fixed in the connector housing 22b. The second lens LE2 focuses the laser light collimated by the first lens LE1. The laser light focused by the second lens LE2 is incident on the second optical fiber 31a. The second lens LE2 also collimates the laser light incident from the second optical fiber 31a side. The laser light collimated by the second lens LE2 is incident on the first lens LE1. Since the treatment light is emitted from the tip of the catheter 30, the transmittance of the treatment light at the connection part 20 is preferably 75% or more, more preferably 80% or more. The transmittance of the test light at the connection part 20 is preferably 20% or more, more preferably 50% or more. If the transmittance of the test light at the connection part 20 is such a transmittance, the connection state of the optical fiber at the connection part 20 can be determined.

[0045] 3 is a schematic diagram showing a state in which the first optical fiber 81a and the second optical fiber 31a are normally connected to each other, in which the test light and the reflected light are indicated by arrows, and the treatment light is not shown.

[0046] The test light TL1 is a test light output from the second laser diode 302. The test light TL1 output from the first optical fiber 81a is incident on the second optical fiber 31a via the first lens LE1 and the second lens LE2. When the test light TL1 is output from the first optical fiber 81a, a part of the test light TL1 is Fresnel reflected to become reflected light RL11, and the reflected light RL11 propagates through the first optical fiber 81a. A part of the test light TL1 that has reached the second optical fiber 31a is Fresnel reflected at the incident end of the second optical fiber 31a to become reflected light RL21. The reflected light R21 reaches the first optical fiber 81a via the second lens LE2 and the first lens LE1, and is incident on the first optical fiber 81a. A part of the reflected light RL21 is Fresnel reflected when it is incident on the first optical fiber 81a.

[0047] Moreover, the test light TL1 propagating through the second optical fiber 31a is reflected by the FBG 32 to become reflected light RL31. The reflected light RL31 propagates in the second optical fiber 31a in the opposite direction to the test light TL1. The reflected light RL31 is output from the second optical fiber 31a. A portion of the reflected light RL31 is Fresnel reflected when output from the second optical fiber 31a. The reflected light RL31 output from the second optical fiber 31a is incident on the first optical fiber 81a via the second lens LE2 and the first lens LE1. A portion of the reflected light RL31 is Fresnel reflected when input to the first optical fiber 81a. The reflected light RL11, the reflected light RL21, and the reflected light RL31 are propagated to the photodiode 401 via the first optical fiber 81a, the optical multiplexer / demultiplexer 701, and the filter 601, and the combined intensity of the propagated reflected light RL11, the reflected light RL21, and the reflected light RL31 is measured by the measurement unit 1001.

[0048] If the intensity of the test light TL1 before being emitted from the first optical fiber 81a is 1, and the transmittance of the set of the first lens LE1 and the second lens LE2 is β, in the state shown in Fig. 3, the combined intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL31 is given by the following formula (1). Note that the reflectance of the FBG32 is 100%. 0.04+0.96*β*(0.04*β*0.96+0.96*0.96*β*0.96)···(1)

[0049] In this embodiment, the Fresnel reflectance at the end face of the optical fiber is 4%, and 0.04 in the first term of equation (1) corresponds to the reflected light RL11. Furthermore, "0.96*β" in "0.04+0.96*β*(0.04*···" in equation (1) corresponds to the test light that is emitted from the first optical fiber 81a and reaches the second optical fiber 31a via the first lens LE1 and the second lens LE2.

[0050] Furthermore, the “0.04*β*0.96” in the parentheses in formula (1) corresponds to the reflected light RL21 incident on the first optical fiber 81a, 0.04 corresponds to the light of the test light that reaches the second optical fiber 31a and is Fresnel reflected, and 0.96 corresponds to the light that is Fresnel reflected by the second optical fiber 31a and then transmitted through the first lens LE1 and the second lens LE2 and incident on the first optical fiber 81a.

[0051] Furthermore, the “0.96*0.96*β*0.96” in the parentheses in equation (1) corresponds to the reflected light RL31 incident on the first optical fiber 81a, the first 0.96 corresponds to the test light incident on the second optical fiber 31a, the next 0.96 corresponds to the light reflected by the FBG32 that exits from the second optical fiber 31a, and the next 0.96 corresponds to the light that exits from the second optical fiber 31a and passes through the first lens LE1 and the second lens LE2 and enters the first optical fiber 81a.

[0052] In the formula (1), when the transmittance β of the pair of the first lens LE1 and the second lens LE2 is 0.95, the combined intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL31 measured by the measurement unit 1001 is 84% ​​of the intensity of the test light TL1. In other words, when the intensity of the reflected light measured by the measurement unit 1001 is 84% ​​or more of the intensity of the test light TL1, it can be said that the first optical fiber 81a and the second optical fiber 31a are normally connected in the connection unit 20.

[0053] Fig. 4 is a schematic diagram showing the configuration of the connection unit 20, illustrating a state in which the second optical fiber 31a is not properly fitted, and therefore the distance between the second lens LE2 and the second optical fiber 31a is longer than in the state shown in Fig. 3. In Fig. 4, the test light and reflected light are also indicated by arrows, and the treatment light is not shown.

[0054] In the state shown in FIG. 4, when the test light TL1 is emitted from the first optical fiber 81a, a part of the test light TL1 is Fresnel reflected to become reflected light RL11, and the reflected light RL11 propagates through the first optical fiber 81a. In addition, in the state shown in FIG. 4, the distance between the second lens LE2 and the second optical fiber 31a is longer than in the normal state. Therefore, compared to the state shown in FIG. 3, the focal point of the second lens LE2 is located upstream of the incident surface of the second optical fiber 31a in the traveling direction of the test light TL1, and a part of the test light TL1 (test light TL12) that has passed through the second lens LE2 does not enter the second optical fiber 31a, and light other than the test light TL12 (test light TL11) enters the second optical fiber 31a. A part of the test light TL11 that has reached the second optical fiber 31a is Fresnel reflected at the incident end of the second optical fiber 31a to become reflected light RL22. The reflected light RL22 enters the first optical fiber 81a. When the reflected light RL22 enters the first optical fiber 81a, a part of the reflected light RL22 is Fresnel reflected.

[0055] Moreover, the test light TL11 propagating through the second optical fiber 31a is reflected by the FBG 32 to become reflected light RL32. The reflected light RL32 propagates in the second optical fiber 31a in the opposite direction to the test light TL11. The reflected light RL32 reaches the first optical fiber 81a via the second lens LE2 and the first lens LE1, and enters the first optical fiber 81a. When the reflected light RL32 is emitted from the second optical fiber 31a, a part of the reflected light RL32 is Fresnel reflected at the incident end of the second optical fiber 31a. Furthermore, a part of the reflected light RL32 is also Fresnel reflected when it enters the first optical fiber 81a. The reflected light RL11, the reflected light RL22, and the reflected light RL32 are propagated to the photodiode 401 via the first optical fiber 81a, the optical multiplexer / demultiplexer 701, and the filter 601, and the combined intensity of the propagated reflected light RL11, the reflected light RL22, and the reflected light RL32 is measured by the measurement unit 1001.

[0056] In the case where the intensity of the test light TL1 before being emitted from the first optical fiber 81a is 1, the transmittance of the set of the first lens LE1 and the second lens LE2 is β, and the coupling efficiency based on the distance between the second lens LE2 and the second optical fiber 31a is x, in the state shown in Fig. 4, the combined intensity of the reflected light RL11, the reflected light RL22, and the reflected light RL32 is obtained by the following formula (2) which adds the coupling efficiency x to formula (1). Note that the coupling efficiency x is set to 1 when the distance between the second lens LE2 and the second optical fiber 31a is normal, that is, when the test light TL11 is not generated, and is set to 0 when the distance between the second lens LE2 and the second optical fiber 31a is not normal and the test light TL1 is not incident on the second optical fiber 31a. 0.04+0.96*β*x*(0.04*β*x*0.96+0.96*0.96*β*x*0.96)...(2)

[0057] When β is 0.95 and the coupling efficiency is 0 to 1, the combined intensity of the reflected light RL11, the reflected light RL22, and the reflected light RL32 measured by the measurement unit 1001 is within a range of 4% to 84% of the intensity of the test light TL1. In other words, when the intensity measured by the measurement unit 1001 is equal to or greater than 4% and less than 84%, it can be said that the first optical fiber 81a and the second optical fiber 31a at the connection unit 20 are in a poorly connected state.

[0058] Fig. 5 is a schematic diagram showing the configuration of the connection unit 20, in which the first optical fiber 81a and the second optical fiber 31a are normally connected and the second optical fiber 31a is broken. In Fig. 5, the test light and reflected light are also indicated by arrows, and the treatment light is not shown.

[0059] When the second optical fiber 31a is broken, the test light TL1 propagating through the second optical fiber 31a may be reflected by the broken surface of the second optical fiber 31a. The light reflected by the broken surface is referred to as reflected light RL33. The reflected light RL33 propagates in the second optical fiber 31a in the opposite direction to the test light TL1. The reflected light RL33 reaches the first optical fiber 81a via the second lens LE2 and the first lens LE1, and enters the first optical fiber 81a. A part of the reflected light RL33 is Fresnel reflected when it is emitted from the second optical fiber 31a, and a part of the reflected light RL33 is also Fresnel reflected when it is entered into the first optical fiber 81a. The reflected light RL11, the reflected light RL21, and the reflected light RL33 are propagated to the photodiode 401 via the first optical fiber 81a, the optical multiplexer / demultiplexer 701, and the filter 601, and the combined intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL33 is measured by the measurement unit 1001.

[0060] If the intensity of the test light TL1 before being emitted from the first optical fiber 81a is 1, the transmittance of the pair of the first lens LE1 and the second lens LE2 is β, and the reflectance at the bent surface of the second optical fiber 31a is α, in the state shown in Figure 5, the combined intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL33 is obtained by the following equation (3), which takes into account the reflectance α in equation (1). 0.04+0.96*β*(0.04*β*0.96+0.96*α*0.96*β*0.96)···(3)

[0061] Since α is a value between 0 and 0.04, when the first optical fiber 81a and the second optical fiber 31a are connected normally and the second optical fiber 31a is broken, the total intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL33 measured by the measurement unit 1001 is within the range of 7.32% to 10.39% of the test light TL1. Note that even when the first optical fiber 81a and the second optical fiber 31a are not connected normally as in the state of FIG. 4, the measured intensity may be within the range of 7.32% to 10.39%. Therefore, when the intensity of the test light TL1 measured by the measurement unit 1001 is within the range of 7.32% to 10.39%, it can be said that the first optical fiber 81a and the second optical fiber 31a are in a poorly connected state in the connection unit 20, or are in a normally connected state with the second optical fiber 31a broken.

[0062] In this way, the intensity of the reflected light measured by the measuring unit 1001 varies depending on the connection state between the first optical fiber 81a and the second optical fiber 31a and the state of the second optical fiber 31a, so that the connection state between the first optical fiber 81a and the second optical fiber 31a and the state of the second optical fiber 31a can be determined based on the intensity of the reflected light measured by the measuring unit 1001. In particular, when the second optical fiber 31a is completely detached from the connection unit 20 according to the above formula (2), the intensity of the reflected light measured by the measuring unit 1001 is 4%, whereas when the second optical fiber 31a is broken according to the above formula (3), the intensity of the reflected light measured by the measuring unit 1001 is 7.32 to 10.39%. In this way, the intensity of the reflected light measured by the measuring unit 1001 when the optical fiber is detached from the connection unit 20 is lower than the intensity of the reflected light measured by the measuring unit 1001 when the optical fiber is broken, i.e., when the optical fiber is broken, so that the two states of detachment and breakage can be completely distinguished.

[0063] 6 is a flow chart showing a process for determining the connection state between the first optical fiber 81a and the second optical fiber 31a. The process shown in FIG. 6 is executed by the control unit 100 when the control unit 100 drives the first laser diode 301 and the second laser diode 302 to output the therapeutic light and the test light.

[0064] First, in step S101, the control unit 100 (measurement unit 1001) measures the intensity of the reflected light of the test light TL1 output from the second laser diode 302 that is reflected and reaches the photodiode 401 based on the current signal supplied from the photodiode 401.

[0065] Next, the control unit 100 (judgment unit 1002) judges whether the measured intensity of the reflected light is less than a predetermined threshold C (step S102). The threshold C is stored in the memory unit. In this embodiment, the threshold C is a value that is 7.32% of the intensity of the test light TL1. If the measured intensity is less than the threshold C (Yes in step S102), the control unit 100 proceeds to step S103. At this point, the control unit 100 judges that there is a poor connection between the first optical fiber 81a and the second optical fiber 31a.

[0066] In step S103, the control unit 100 (notification unit 1003) controls the display unit 200 to notify using letters or symbols that the first optical fiber 81a and the second optical fiber 31a are in a poor connection state at the connection unit 20, and then terminates the processing of Figure 6.

[0067] On the other hand, if the measured intensity is equal to or greater than the threshold C (No in step S102), the control unit 100 proceeds to step S104. In step S104, the control unit 100 determines whether the measured intensity of the reflected light is equal to or greater than the threshold C and equal to or less than a predetermined threshold B. In this embodiment, the threshold B is 10.39% of the intensity of the test light TL1. The threshold B is stored in the memory unit. If the measured intensity of the reflected light is equal to or greater than the threshold C and equal to or less than the threshold B (Yes in step S104), the control unit 100 proceeds to step S105. At this point, the control unit 100 has determined that there is a poor connection between the first optical fiber 81a and the second optical fiber 31a or that the second optical fiber 31a is broken.

[0068] In step S105, the control unit 100 controls the display unit 200 to notify with characters or symbols that the first optical fiber 81a and the second optical fiber 31a are poorly connected in the connection unit 20 or that the second optical fiber 31a is broken, and then ends the process in Fig. 6. Note that in step S105, the control unit 100 may provide a notification to prompt confirmation of the connection between the first optical fiber 81a and the second optical fiber 31a. Furthermore, the control unit 105 may perform a process of stopping the drive of the first laser diode 301 before or after step S105.

[0069] If the measured intensity exceeds threshold B (No in step S104), the control unit 100 proceeds to step S106. In step S106, the control unit 100 determines whether the measured intensity of the reflected light exceeds threshold B and is less than a predetermined threshold A. In this embodiment, threshold A is a value that is 84% ​​of the intensity of the test light TL1. Threshold A is stored in the memory unit. Threshold A is an example of a first threshold.

[0070] If the measured intensity of the reflected light exceeds threshold B and is less than threshold A (Yes in step S106), the control unit 100 proceeds to step S107. Here, the control unit 100 determines that there is a poor connection between the first optical fiber 81a and the second optical fiber 31a. In step S107, the control unit 100 controls the display unit 200 to notify with characters or symbols that there is a poor connection between the first optical fiber 81a and the second optical fiber 31a at the connection unit 20, and then ends the processing in FIG.

[0071] If the measured intensity is equal to or greater than threshold A (No in step S106), the control unit 100 proceeds to step S108. Here, the control unit 100 determines that the connection between the first optical fiber 81a and the second optical fiber 31a is normal and that the second optical fiber 31a is not broken. The control unit 100 controls the display unit 200 in step S108 to notify with characters or symbols that the connection between the first optical fiber 81a and the second optical fiber 31a at the connection unit 20 is normal and that the second optical fiber 31a is not broken, and then ends the processing in FIG.

[0072] As described above, in the first embodiment, the connection state between the first optical fiber 81a and the second optical fiber 31a at the connection portion 20 and the state of the second optical fiber 31a can be determined based on the measurement results of the intensity of the reflected light of the test light TL1 that is reflected and reaches the photodiode 401, and the determination result can be notified to the operator.

[0073] The above-mentioned threshold values ​​A, B, and C are all merely examples, and are not limited to the above-mentioned values. For example, when the second optical fiber 31a is broken and the distance between the second lens LE2 and the second optical fiber 31a is not normal, the intensity of the measured reflected light may be less than 7.32% of the intensity of the test light TL1. For this reason, when the measured intensity is equal to or less than the threshold value B, the control unit 100 may determine that the first optical fiber 81a and the second optical fiber 31a are poorly connected or that the second optical fiber 31a is broken, and may notify the connection unit 20 of the poor connection between the first optical fiber 81a and the second optical fiber 31a or the broken state of the second optical fiber 31a by using characters or symbols. In the above-mentioned embodiment, the threshold value A is set to 84% of the test light TL1, but may be set to, for example, 79% of the test light TL1 to allow a margin for determining the connection. Furthermore, when an AR (anti-reflection) coating is applied to the end face of the optical fiber, the reflectance of light at the end face of the optical fiber becomes lower than 4%, which is the reflectance in the case of Fresnel reflection, so the values ​​of thresholds A, B, and C may be set according to the coating. In the above-mentioned embodiment, the wavelength of the therapeutic light is within the range of 600 nm to 1500 nm, but when an AR coating is applied to the end face of the optical fiber, the wavelength of the therapeutic light is preferably within the range of 900 nm to 1050 nm. If the wavelength of the therapeutic light is within the range of 900 nm to 1050 nm, the reflection of the therapeutic light and the test light at the end face of the optical fiber can be suppressed with a single type of AR coating.

[0074] In this embodiment, the second laser diode 302 may be driven to perform the process shown in Fig. 6 each time the button of the operated unit 801 is operated by the operator. In this configuration, for example, the control unit 100 determines that the first optical fiber 81a and the second optical fiber 31a are in a poor connection state or that the second optical fiber 31a is broken by the process according to the first operation of the button, and for example, the operator receives this notification and redoes the connection of the optical fibers in the connection unit 20. Thereafter, the control unit 100 performs the process shown in Fig. 6 in response to the second operation of the button, and when it is determined again that the first optical fiber 81a and the second optical fiber 31a are in a poor connection state or that the second optical fiber 31a is broken, that is, when the result of the determination performed for each operation is repeatedly determined to be a poor connection, it is considered that the poor connection will be improved by the operator redoing the connection, so it may determine that the second optical fiber 31a is broken and notify the operator that the second optical fiber 31a is in a broken state by using characters or symbols. According to this configuration, it is possible to inform the operator that the second optical fiber 31a is broken.

[0075] In the first embodiment, another example of a connection failure of the optical fibers may be a case where an optical axis misalignment occurs between the first lens LE1 and the second lens LE2, causing the test light TL12 to not enter the second optical fiber 31a. In such a case, the coupling efficiency according to the axis misalignment may be, for example, y, which may be added to equation (2) to set thresholds A, B, and C. The coupling efficiency y may be, for example, 1 when no axis misalignment occurs, and 0 when the test light TL1 does not enter the second optical fiber 31a due to the axis misalignment.

[0076] [Second embodiment] Next, a second embodiment of the present invention will be described. In the second embodiment, compared to the first embodiment, the diameter of the first optical fiber 81a is smaller than the diameter of the second optical fiber 31a, and the method of connecting the first optical fiber 81a and the second optical fiber 31a at the connection unit 20 and the process executed by the control unit 100 are different, but the other configurations are the same as those of the first embodiment. Therefore, in the following description, the description of the same configuration as the first embodiment will be omitted, and the differences from the first embodiment will be described.

[0077] Fig. 7 is a schematic diagram showing an example of a connection state of optical fibers in the connection unit 20 according to the second embodiment. Fig. 7 shows a state in which there is no air gap between the first optical fiber 81b and the second optical fiber 31a and they are normally connected. The first optical fiber 81b is an optical fiber whose core diameter is smaller than the core diameter of the second optical fiber 31a. The first optical fiber 81b is connected to an optical multiplexer / demultiplexer 701 and propagates the therapeutic light and test light output from the optical multiplexer / demultiplexer 701. The first optical fiber 81b and the second optical fiber 31a are butt-jointed to each other in the connection unit 20 by a sleeve and a ferrule (not shown).

[0078] In FIG. 7, the test light and the reflected light are indicated by arrows, and the therapeutic light is not shown. The test light TL1 is the test light output from the second laser diode 302. The test light TL1 enters the second optical fiber 31a from the first optical fiber 81b. The test light TL1 propagates through the second optical fiber 31a and is reflected by the FBG 32 to become the reflected light RL31. The reflected light RL31 propagates in the second optical fiber 31a in the opposite direction to the test light TL1. Since the core diameter of the first optical fiber 81b is smaller than the core diameter of the second optical fiber 31a, a part of the reflected light RL31 enters the first optical fiber 81b. The reflected light RL51 shown in FIG. 7 represents the light of the reflected light RL31 that enters the core of the first optical fiber 81b, and the reflected light RL52 shown in FIG. 7 represents the light of the reflected light RL31 that does not enter the core of the first optical fiber 81b. The reflected light RL51 is propagated to the photodiode 401 via the first optical fiber 81b, the optical multiplexer / demultiplexer 701, and the filter 601, and the intensity is measured by the measuring unit 1001.

[0079] If the intensity of the test light TL1 before it is emitted from the first optical fiber 81b is 1, the reflectance of the test light TL1 at the FBG 32 is 100%, and the connection loss due to the difference between the core diameter of the first optical fiber 81b and the core diameter of the second optical fiber 31a is γ, the intensity measured in the state shown in Figure 7 can be obtained by the following equation (4). 1.00*γ (4)

[0080] In this embodiment, γ is the area ratio between the cross-sectional area of ​​the core of the first optical fiber 81b and the cross-sectional area of ​​the core of the second optical fiber 31a. For example, when the core diameter of the first optical fiber 81b is 105 μm and the core diameter of the second optical fiber 31a is 120 μm, γ is 0.766. When the connection state of the first optical fiber 81b and the second optical fiber 31a is as shown in FIG. 7 and γ=0.766, the intensity of the reflected light RL51 measured by the measurement unit 1001 is 76.6% of the intensity of the test light TL1.

[0081] 8 is a schematic diagram showing a state in which the first optical fiber 81b and the second optical fiber 31a are connected normally with no air gap between them at the connection portion 20, but the second optical fiber 31a is broken. In Fig. 8 as well, the test light and the reflected light are indicated by arrows, and the treatment light is omitted.

[0082] As shown in FIG. 8, when the second optical fiber 31a is broken, the test light TL1 propagated through the second optical fiber 31a may be reflected by the broken surface of the second optical fiber 31a. The light reflected by the broken surface is referred to as reflected light RL34. The reflected light RL34 propagates in the second optical fiber 31a in the opposite direction to the test light TL1. Since the diameter of the core of the first optical fiber 81b is smaller than the diameter of the core of the second optical fiber 31a, a part of the reflected light RL34 is incident on the first optical fiber 81b. The reflected light RL53 shown in FIG. 8 represents the light of the reflected light RL34 that is incident on the first optical fiber 81b, and the reflected light RL54 shown in FIG. 8 represents the light of the reflected light RL34 that is not incident on the first optical fiber 81b. The reflected light RL53 is propagated to the photodiode 401 via the first optical fiber 81b, the optical multiplexer / demultiplexer 701, and the filter 601, and the intensity is measured by the measuring unit 1001.

[0083] If the intensity of the test light TL1 before being emitted from the first optical fiber 81a is 1, the connection loss due to the difference between the core diameter of the first optical fiber 81b and the core diameter of the second optical fiber 31a is γ, and the reflectance at the bent surface of the second optical fiber 31a is α, the intensity measured in the state shown in Figure 8 can be obtained by the following equation (5). 1.00*γ*α (5)

[0084] Since α is a value between 0 and 0.04, when the connection state of the first optical fiber 81b and the second optical fiber 31a is as shown in Figure 8 and γ = 0.766, the intensity of the reflected light RL53 measured by the measurement unit 1001 is within the range of 0% to 3.06% of the intensity of the test light TL1.

[0085] 9 is a schematic diagram showing a state in which the second optical fiber 31a is not broken, but there is an air gap between the first optical fiber 81b and the second optical fiber 31a, resulting in an improper connection. In FIG. 9, the test light and the reflected light are indicated by arrows, and the treatment light is omitted.

[0086] 9, when the test light TL1 is output from the first optical fiber 81a, a part of the test light TL1 is Fresnel reflected to become reflected light RL11, and the reflected light RL11 propagates through the first optical fiber 81a. In addition, a part of the test light TL1 output from the first optical fiber 81a is Fresnel reflected at the input end of the second optical fiber 31a to become reflected light RL21. The reflected light RL21 enters the first optical fiber 81b. A part of the reflected light RL21 is Fresnel reflected when it enters the first optical fiber 81b.

[0087] Furthermore, the light of the test light TL1 that is incident on the second optical fiber 31a propagates through the second optical fiber 31a and is reflected by the FBG 32 to become reflected light RL35. The reflected light RL35 propagates in the second optical fiber 31a in the opposite direction to the test light TL1. The reflected light RL35 is output from the second optical fiber 31a. When the reflected light RL35 is output from the second optical fiber 31a, a part of the reflected light RL35 is Fresnel reflected at the input end of the second optical fiber 31a.

[0088] Since the diameter of the first optical fiber 81b is smaller than that of the second optical fiber 31a, a portion of the reflected light RL35 emitted from the second optical fiber 31a is incident on the first optical fiber 81b. Reflected light RL55 shown in Fig. 9 represents the light of the reflected light RL35 that is incident on the first optical fiber 81b, and reflected light RL56 represents the light of the reflected light RL35 that is not incident on the first optical fiber 81b. Note that a portion of the reflected light RL35 is also Fresnel reflected when it is incident on the first optical fiber 81a.

[0089] The reflected light RL11, the reflected light RL21, and the reflected light RL55 are propagated to the photodiode 401 via the first optical fiber 81b, the optical multiplexer / demultiplexer 701, and the filter 601, and the combined intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL51 is measured by the measurement unit 1001.

[0090] If the intensity of the test light TL1 before being emitted from the first optical fiber 81a is 1, the reflectance of the test light TL1 in the FBG 32 is 100%, the connection loss due to the difference in diameter between the first optical fiber 81b and the second optical fiber 31a is γ, and the coupling efficiency between the first optical fiber 81a and the second optical fiber 31a is x, the intensity measured in the state shown in Fig. 9 is obtained by the following formula (6). Note that the coupling efficiency here is based on the air gap, and a state in which the first optical fiber 81b and the second optical fiber 31a are in contact with each other and all of the test light TL1 is incident on the second optical fiber 31a is 1, and a state in which none of the test light TL1 is incident on the second optical fiber 31a is 0. 0.04+x 2 *gamma*0.96 2 (0.04+0.96 2 ) · · · (6)

[0091] When γ=0.766, the combined intensity of the reflected light RL11, the reflected light RL21, and the reflected light RL55 measured by the measurement unit 1001 is within a range of 4% to 71.2% of the intensity of the test light TL1. That is, when the intensity measured by the measurement unit 1001 is 4% or more and 71.2% or less, it can be said that the first optical fiber 81b and the second optical fiber 31a at the connection unit 20 are in a poor connection state.

[0092] In this way, the intensity of the reflected light measured by the measuring unit 1001 varies depending on the connection state between the first optical fiber 81b and the second optical fiber 31a and the state of the second optical fiber 31a, so that the connection state between the first optical fiber 81b and the second optical fiber 31a and the state of the second optical fiber 31a can be determined based on the intensity of the reflected light measured by the measuring unit 1001. In particular, when the second optical fiber 31a is completely detached from the connection unit 20 according to the above-mentioned formula (6), the intensity of the reflected light measured by the measuring unit 1001 is 4%, whereas when the second optical fiber 31a is broken according to the above-mentioned formula (5), the intensity of the reflected light measured by the measuring unit 1001 is 0 to 3.06%. In this way, the intensity of the reflected light measured by the measuring unit 1001 when the second optical fiber 31a is broken is lower than the intensity of the reflected light measured by the measuring unit 1001 when the second optical fiber 31a is detached from the connection unit 20, so that the two states of breakage and detachment can be completely distinguished.

[0093] 10 is a flow chart showing a process for determining the connection state between the first optical fiber 81b and the second optical fiber 31a. The process shown in FIG. 10 is executed by the control unit 100, for example, when the control unit 100 drives the first laser diode 301 and the second laser diode 302 to output the therapeutic light and the test light.

[0094] First, in step S201, the control unit 100 (measurement unit 1001) measures the intensity of the reflected light of the test light TL1 output from the second laser diode 302 that is reflected and reaches the photodiode 401 based on the current signal supplied from the photodiode 401.

[0095] Next, the control unit 100 (judgment unit 1002) judges whether the measured intensity of the reflected light is equal to or less than a predetermined threshold D (step S202). In this embodiment, the threshold D is 3.06% of the intensity of the test light TL1. The threshold D is stored in the memory unit. The threshold D is an example of a fourth threshold. If the measured intensity is equal to or less than the threshold D (Yes in step S202), the control unit 100 proceeds to step 203. At this point, the control unit 100 judges that the second optical fiber 31a is broken.

[0096] In step S203, the control unit 100 (light source control unit 1004) determines whether at least one of the first laser diode 301 and the second laser diode 302 is being driven. If at least one of the first laser diode 301 and the second laser diode 302 is being driven (Yes in step S203), the control unit 100 proceeds to step S204, and if neither the first laser diode 301 nor the second laser diode 302 is being driven (No in step S203), the control unit 100 proceeds to step S205.

[0097] When the control unit 100 proceeds to step S204, it stops driving the first laser diode 301 and the second laser diode 302 in step S204, and proceeds to step S205. In step S205, the control unit 100 controls the display unit 200 to notify the user by using characters or symbols that the optical fiber of the catheter 30 is broken, and then ends the process of FIG.

[0098] On the other hand, if the measured intensity exceeds the threshold D (No in step S202), the control unit 100 proceeds to step S206. The control unit 100 determines in step S206 whether the measured intensity of the reflected light is equal to or greater than a predetermined threshold E and equal to or less than a predetermined threshold F. In this embodiment, the threshold E is 4% of the intensity of the test light TL1, and the threshold F is 71.2% of the intensity of the test light TL1. The thresholds E and F are stored in the storage unit. The threshold E is an example of a second threshold, and the threshold F is an example of a third threshold. If the measured intensity of the reflected light is equal to or greater than the threshold E and equal to or less than the threshold F (Yes in step S206), the control unit 100 proceeds to step S207. Here, the control unit 100 determines that the first optical fiber 81b and the second optical fiber 31a are poorly connected. In step S207, the control unit 100 controls the display unit 200 to notify the user by using characters or symbols that the optical fiber is in a poor connection state in the connection unit 20, and then ends the process of FIG.

[0099] If the measured intensity is not equal to or greater than threshold E and equal to or less than threshold F (No in step S206), the control unit 100 proceeds to step S208. In step S208, the control unit 100 determines whether the measured intensity of the reflected light is equal to or greater than a predetermined threshold G. In this embodiment, the threshold G is 76.6% of the intensity of the test light TL1. The threshold G is stored in the memory unit.

[0100] If the measured intensity of the reflected light is less than the threshold G (No in step S208), the control unit 100 proceeds to step S207. Here, the control unit 100 determines that the first optical fiber 81b and the second optical fiber 31a are poorly connected. If the measured intensity of the reflected light is equal to or greater than the threshold G (Yes in step S208), the control unit 100 proceeds to step S209. Here, the control unit 100 determines that the connection between the first optical fiber 81b and the second optical fiber 31a is normal and that the second optical fiber 31a is not broken. In step S209, the control unit 100 controls the display unit 200 to notify with characters or symbols that the connection of the optical fiber in the connection unit 20 is normal and that the optical fiber is not broken, and then ends the processing of FIG. 10.

[0101] In addition, when there is no air gap between the first optical fiber 81b and the second optical fiber 31a, but the first optical fiber 81b and the second optical fiber 31a are misaligned, the intensity measured by the measuring unit 1001 is given by the following equation (7), which takes into account the coupling efficiency x based on the axial misalignment in addition to the above equation (4). 1.00*γ*x 2 (7)

[0102] x is in the range of 0 to 1, and if there is no loss when the test light TL1 enters the second optical fiber 31a from the first optical fiber 81b, x=1, and the intensity of the reflected light measured by the measuring unit 1001 is 76.6% of the intensity of the test light TL1. If the first optical fiber 81b and the second optical fiber 31a are misaligned and there is loss when the test light TL1 enters the second optical fiber 31a from the first optical fiber 81b and when the reflected light reflected by the FBG 32 enters the first optical fiber 81b from the second optical fiber 31a, the value of x is less than 1, and the intensity of the reflected light entering the first optical fiber 81b is less than 76.6% of the intensity of the test light TL1. For this reason, the control unit 100 may proceed to step S207 if the measured intensity of the reflected light is equal to or greater than the threshold E and less than the threshold G in step S206, for example. In this case, the control unit 100 determines that the first optical fiber 81b and the second optical fiber 31a are in a poorly connected state.

[0103] In the second embodiment, based on the measurement results of the intensity of the reflected light of the test light TL1 that is reflected and enters the first optical fiber 81b, the connection state between the first optical fiber 81b and the second optical fiber 31a at the connection portion 20 and the state of the second optical fiber 31a can be determined, and the determination result can be notified to an operator.

[0104] [Variations] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and can be implemented in various other forms. For example, the above-mentioned embodiment may be modified as follows to implement the present invention. The above-mentioned embodiment and the following modifications may be combined with each other. The present invention also includes a configuration in which the components of the above-mentioned embodiments and modifications are appropriately combined. Further effects and modifications can be easily derived by a person skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment and modifications, and various modifications are possible.

[0105] In the first embodiment described above, the threshold A is set to 84% of the intensity of the test light TL1, but in order to allow some leeway in determining whether the connection is normal, the value of the threshold A may be set to, for example, 79% of the intensity of the test light TL1.

[0106] In the second embodiment described above, the core diameter of the first optical fiber 81b and the core diameter of the second optical fiber 31a are different, but the core diameter of the first optical fiber 81b and the core diameter of the second optical fiber 31a may be the same when performing butt splicing. In this case, the value of γ in the above formulas (4) to (6) is 1. In this case, the values ​​of threshold D, threshold E, threshold F, and threshold G may be set according to the values ​​that can be taken when γ=1 in the above formulas (4) to (6).

[0107] In the second embodiment described above, the first optical fiber 81b and the second optical fiber 31a are connected by butt splicing, but instead of butt splicing, a spatial coupling configuration using lenses as in the first embodiment may be used. In this case, thresholds for determining whether the optical fiber is broken, whether the optical fiber is poorly connected, and whether the optical fiber is normally connected may be determined according to the transmittance of the set of the first lens LE1 and the second lens LE2, the coupling efficiency due to an air gap or axial misalignment, Fresnel reflection, and the area ratio between the first optical fiber 81b and the second optical fiber 31a, and each determination may be made according to the determined thresholds.

[0108] In the above-described first embodiment, the control unit 100 may determine that the connection between the first optical fiber 81a and the second optical fiber 31a is poor regardless of the value of the intensity when the measured intensity is less than the threshold value A. In this case, for example, if the notification of poor connection continues even after the operator reconnects the first optical fiber 81a and the second optical fiber 31a at the connection unit 20, the operator can determine that the connection is not poor but that the second optical fiber 31a is broken.

[0109] In the above-described embodiment, the display unit 200 notifies the user of a poor optical fiber connection or a broken optical fiber. However, the laser device 10 may be provided with a speaker so that the user can hear the poor optical fiber connection or a broken optical fiber by audio.

[0110] In the first and second embodiments described above, the number of first laser diodes 301 serving as the light source of the therapeutic light is one, but there may be more than one first laser diode 301. When there are more than one first laser diodes 301, the therapeutic light output from the multiple first laser diodes 301 may be multiplexed by a multiplexer and input to the optical multiplexer / demultiplexer 701.

[0111] In the above embodiment, the therapeutic light is multiplexed with the test light before being input to the optical multiplexer / demultiplexer 701, but the therapeutic light may be multiplexed with the test light between the optical multiplexer / demultiplexer 701 and the connection unit 20. The optical multiplexer / demultiplexer 701 may be configured to spatially multiplex a plurality of lights, or may be configured to multiplex using an optical combiner or the like.

[0112] Depending on the configuration, the filter 601 may not be necessary. For example, when the optical multiplexer / demultiplexer 701 is a WDM coupler, the extinction ratio is high and efficient demultiplexing can be performed, so the filter 601 may not be provided.

[0113] The above-described embodiment is not limited to a system that outputs laser light for treatment, but can be applied to a system that outputs laser light by detachably connecting an optical fiber with a connector.

[0114] In the above-mentioned embodiments, the catheter may be configured to include a tap coupler. Fig. 11 is a diagram showing the configuration of a catheter 30A including a tap coupler 34. In Fig. 11, the same elements as those in the catheter 30 are given the same reference numerals. The catheter 30A includes a second optical fiber 31a, an optical fiber 31b, an optical fiber 31c, an FBG 32, a catheter body 33, a tap coupler 34, and a terminal end 35. The optical fiber 31b is an example of a second optical fiber. The terminal end 35 is an example of a reflecting section.

[0115] The tap coupler 34 is an asymmetric tap coupler with 1×2 ports and a branching ratio of 90:10. In the tap coupler 34, the optical fiber 31b is connected to the main port where the proportion of branched light is large. The test light TL1 propagated through the optical fiber 31b is reflected by the FBG 32 and propagates in the opposite direction to the test light TL1, and propagates to the laser device 10 via the tap coupler 34, the second optical fiber 31a, the connection unit 20, and the first optical fiber 81a.

[0116] Further, the optical fiber 31c is connected to a sub-port having a small proportion of branched light in the tap coupler 34. A termination unit 35 that performs termination processing of the optical fiber is connected to the tip of the optical fiber 31c.

[0117] The terminal end 35 may have a reflective film formed thereon so that the reflectance of the test light TL1 propagated through the tap coupler 34 is 90% or more. In this configuration, when the optical fiber 31b is broken, the reflected light reflected at the broken surface and the reflected light from the terminal end 35 propagate to the laser device 10. Even if the optical fiber 31b is broken, there is reflected light from the terminal end 35, so the intensity of the reflected light measured by the measuring unit 1001 when the second optical fiber 31a is detached from the connection unit 20 is lower than the intensity of the reflected light measured by the measuring unit 1001 when the optical fiber 31b is broken. Therefore, similar to the first embodiment, the two states of detachment and breakage can be completely distinguished from each other.

[0118] The end 35 may be, for example, a tip of the optical fiber 31c that is cut obliquely so that the reflectance of the test light TL1 is 4% or less. In this configuration, when the optical fiber 31b is broken, the reflected light reflected at the broken surface propagates to the laser device 10. Here, the test light TL1 propagated through the optical fiber 31b is branched by the tap coupler 34 and its intensity is reduced, so that the reflected light reflected at the broken surface of the optical fiber 31b and propagated to the laser device 10 is also reduced. On the other hand, since the reflectance of the end 35 is low, the test light TL1 that reaches the end 35 does not propagate to the laser device 10 even if it is reflected by the end 35. In this way, when the reflected light of the test light TL1 from the end 35 does not propagate to the laser device 10, the intensity of the reflected light measured by the measuring unit 1001 when the optical fiber 31b is broken is lower than the intensity of the reflected light measured by the measuring unit 1001 when the second optical fiber 31a is detached from the connecting unit 20. Therefore, similarly to the second embodiment, the two states of detachment and disconnection can be completely distinguished. [Industrial Applicability]

[0119] The present invention can be used in a system for determining the connection state of an optical fiber and a method for determining the connection state of an optical fiber. [Explanation of symbols]

[0120] 1 Laser system 10 Laser device (connection status determination system) 20 Connection 21a, 21b Ferrules 22a, 22b Connector housing 30, 30A catheter 31a Second optical fiber 31b, 31c Optical fiber 32 Fiber Bragg Grating (FBG) 33 Catheter body 34 Tap Coupler 35 End 81a, 81b First optical fiber 100 Control section 200 Display 301 First laser diode 302 Second laser diode 401 Photodiode 501 Multiplexer 601 Filter 701 Optical multiplexer / demultiplexer 801 Operated part 1001 Measuring part 1002 Judgment Department 1003 Notification Department 1004 Light source control unit LE1 First lens LE2 2nd lens

Claims

1. A system for judging a connection state of a first optical fiber and a second optical fiber at a connection part which detachably connects an output side of a first optical fiber which propagates test light input from a light source and outputs the test light, and an input side of a second optical fiber which inputs the test light propagated through the first optical fiber and output from the first optical fiber, the system comprising: a measurement unit for measuring an intensity of a reflected light of the test light that is reflected and propagates through the first optical fiber; a determination unit that determines a connection state of the first optical fiber and the second optical fiber at the connection portion based on the strength measured by the measurement unit; Equipped with When the test light is emitted from the first optical fiber, a part of the test light is Fresnel reflected to become reflected light, and the reflected light propagates through the first optical fiber, the test light emitted from the first optical fiber reaches the second optical fiber via a first lens and a second lens, A portion of the test light that has reached the second optical fiber from the second lens is incident on the second optical fiber, When the test light reaches the second optical fiber from the second lens, a part of the test light is Fresnel reflected at the incident end of the second optical fiber to become reflected light, and the reflected light is incident on the first optical fiber via the first lens and the second lens, an intensity of the reflected light measured by the measuring unit differs between a case where the second optical fiber is broken and a case where the second optical fiber is detached from the connection unit; The intensity of the reflected light measured by the measuring unit when the second optical fiber is broken is greater than the intensity of the reflected light measured by the measuring unit when the second optical fiber is detached from the connecting unit. Optical fiber connection status determination system.

2. the first optical fiber and the second optical fiber are spatially coupled at the connection portion; The determination unit determines that a connection between the first optical fiber and the second optical fiber is poor when the intensity is less than a first threshold value.

2. The optical fiber connection status determination system according to claim 1.

3. an optical fiber coupler is connected to the second optical fiber; The test light emitted from a predetermined port among a plurality of ports from which the test light is emitted in the optical fiber coupler is reflected by a reflecting portion that reflects the test light.

2. The optical fiber connection status determination system according to claim 1.

4. The measurement unit performs a measurement every time a measurement operation is performed by an operator, The determination unit determines the connection state every time the measurement unit performs a measurement, and determines that the second optical fiber is broken if the determination result indicates a connection failure. The optical fiber connection state determination system according to any one of claims 1 to 3.

5. a notification unit that notifies a connection state between the first optical fiber and the second optical fiber according to a result of the determination by the determination unit; The optical fiber connection state determination system according to claim 1 , further comprising:

6. A laser beam for cauterizing a human body is input to the first optical fiber after being combined with the test beam; When the determining unit determines that the second optical fiber is broken, the output of the laser light from a light source that outputs the laser light is stopped. The optical fiber connection state determination system according to any one of claims 1 to 5.

7. A method for determining a connection state of a first optical fiber and a second optical fiber in a connection section in which an output side of a first optical fiber that propagates test light input from a light source and outputs the test light are detachably connected to an input side of a second optical fiber to which the test light propagated through the first optical fiber and output from the first optical fiber is input, comprising: a measuring step of measuring an intensity of a reflected light that is reflected from the test light and propagates through the first optical fiber; a determination step of determining a connection state of the first optical fiber and the second optical fiber based on the strength measured in the measurement step; Equipped with When the test light is emitted from the first optical fiber, a part of the test light is Fresnel reflected to become reflected light, and the reflected light propagates through the first optical fiber, the test light emitted from the first optical fiber reaches the second optical fiber via a first lens and a second lens, A portion of the test light that has reached the second optical fiber from the second lens is incident on the second optical fiber, When the test light reaches the second optical fiber from the second lens, a part of the test light is Fresnel reflected at the incident end of the second optical fiber to become reflected light, and the reflected light is incident on the first optical fiber via the first lens and the second lens, an intensity of the reflected light measured in the measuring step differs between a case where the second optical fiber is broken and a case where the second optical fiber is detached from the connection portion; The intensity of the reflected light measured in the measuring step when the second optical fiber is broken is greater than the intensity of the reflected light measured in the measuring step when the second optical fiber is detached from the connection portion. A method for determining the connection status of optical fibers.

Images