阅读说明：本技术 光纤的状态检测系统 (Optical fiber state detection system ) 是由 野村义树 渡边健吾 松下俊一 于 2020-03-25 设计创作，主要内容包括：目的在于提供能够准确地测定使光纤动作时的弯曲损耗而判定光纤的弯曲的有无的光纤的状态检测系统。光纤的状态检测系统(1)具备：监视器用LD(11),输出对光纤(50)的状态进行监视的监视用光(TL)；反射机构(31),反射在光纤(50)内传播的监视用光(TL)；监视器PD(12),接受被反射机构(31)反射后的反射光(RL)；抽头耦合器(13),设置于监视器用LD(11)及监视器PD(12)与反射机构(31)之间且连接了监视器用LD(11)及监视器PD(12)；和控制部(60),控制部(60)在检测到反射光(RL)的受光强度低于给定的阈值的情况下,判定为光纤(50)产生弯曲。(Provided is an optical fiber state detection system capable of accurately measuring the bending loss when an optical fiber is operated to determine whether the optical fiber is bent or not. An optical fiber state detection system (1) is provided with: a monitor LD (11) for outputting monitoring light (TL) for monitoring the state of the optical fiber (50); a reflection mechanism (31) that reflects monitoring light (TL) propagating through the optical fiber (50); a monitor PD (12) for receiving the Reflected Light (RL) reflected by the reflection mechanism (31); a tap coupler (13) which is provided between the monitor LD (11) and the monitor PD (12) and the reflection mechanism (31) and which connects the monitor LD (11) and the monitor PD (12); and a control unit (60), wherein the control unit (60) determines that the optical fiber (50) is bent when the control unit detects that the received light intensity of the Reflected Light (RL) is lower than a predetermined threshold value.)

1. An optical fiber state detection system comprising:

a first light source that outputs monitoring light for monitoring the state of the optical fiber;

a reflecting mechanism that reflects the monitoring light propagating in the optical fiber;

a light receiving unit that receives the reflected light reflected by the reflecting mechanism;

a tap coupler disposed between the first light source and the light receiving unit and the reflection mechanism, and connecting the first light source and the light receiving unit; and

a control part for controlling the operation of the display device,

the control unit outputs information that the received light intensity has decreased to the outside when it is detected that the received light intensity of the reflected light is greater than 0 and lower than a predetermined threshold value.

2. An optical fiber state detection system comprising:

a first light source that outputs monitoring light for monitoring the state of the optical fiber;

a reflecting mechanism that reflects the monitoring light propagating in the optical fiber;

a light receiving unit that receives the reflected light reflected by the reflecting mechanism;

a tap coupler disposed between the first light source and the light receiving unit and the reflection mechanism, and connecting the first light source and the light receiving unit;

a second light source for outputting light for cauterization;

a combiner for combining the monitoring light and the burning light; and

a control part for controlling the operation of the display device,

the first light source and the second light source are connected to the multiplexer,

the combiner and the light receiving section are connected to the tap coupler,

the monitoring light and the cauterizing light have different wavelengths,

the reflecting mechanism transmits the light for cauterization,

the control unit turns off the second light source when it is detected that the received light intensity of the reflected light is greater than 0 and lower than a predetermined threshold value.

3. The optical fiber status detecting system according to claim 1 or 2,

the wavelength of the monitoring light is a wavelength of a visible light band.

4. The optical fiber status detecting system according to any one of claims 1 to 3,

the monitoring light is a flat-topped beam.

5. A condition detecting system of an optical fiber according to claim 2 or claim 3 or 4 depending on claim 2,

the monitoring light and the cauterizing light have the same beam shape.

6. A condition detecting system of an optical fiber according to claim 2 or any one of claims 3 to 5 depending on claim 2,

a mechanism for cutting off the wavelength of the burning light is provided on the near side of the light receiving unit.

Technical Field

The present invention relates to a state detection system for an optical fiber.

Background

A technique of inserting a catheter into which an optical fiber is inserted into a patient to perform treatment is known. In such a medical optical fiber probe or the like, since the diameter of the optical fiber is also reduced as the diameter of the catheter is reduced, there is a risk that the optical fiber is strongly bent or bent when inserted into the body of a patient.

For example, patent documents 1 and 2 disclose techniques for detecting bending of a tubular body of an endoscope or the like inserted into the body or estimating a bent shape.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2001-1699998

Patent document 2: japanese patent laid-open publication No. 2015-181643

Disclosure of Invention

The technical problem to be solved by the invention

When the optical fiber is strongly bent during insertion of the catheter, light leaks out at the bent portion. Therefore, for example, when performing laser ablation treatment, there is a possibility that light energy reaching a desired site is reduced or unnecessary sites are ablated due to leakage of light in a curved portion.

Therefore, a technique is required for accurately measuring the bending loss when the catheter is inserted, that is, when the optical fiber is operated, and determining the presence or absence of bending of the optical fiber. However, such a technique is not disclosed in patent documents 1 and 2.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a state detection system for an optical fiber, which can accurately measure a bending loss when the optical fiber is operated and can determine whether or not the optical fiber is bent.

Means for solving technical problems

In order to solve the above problems and achieve the object, an optical fiber state detection system according to an aspect of the present invention includes: a first light source that outputs monitoring light for monitoring the state of the optical fiber; a reflecting mechanism that reflects the monitoring light propagating in the optical fiber; a light receiving unit that receives the reflected light reflected by the reflecting mechanism; a tap coupler disposed between the first light source and the light receiving unit and the reflection mechanism, and connecting the first light source and the light receiving unit; and a control unit that outputs information indicating that the received light intensity has decreased to the outside when it is detected that the received light intensity of the reflected light is greater than 0 and lower than a predetermined threshold value.

An optical fiber state detection system according to an aspect of the present invention includes: a first light source that outputs monitoring light for monitoring the state of the optical fiber; a reflecting mechanism that reflects the monitoring light propagating in the optical fiber; a light receiving unit that receives the reflected light reflected by the reflecting mechanism; a tap coupler disposed between the first light source and the light receiving unit and the reflection mechanism, and connecting the first light source and the light receiving unit; a second light source for outputting light for cauterization; a combiner for combining the monitoring light and the burning light; and a control unit, wherein the first light source and the second light source are connected to the multiplexer, the multiplexer and the light receiving unit are connected to the tap coupler, the monitoring light and the burning light have different wavelengths, the reflection mechanism transmits the burning light, and the control unit turns off the second light source when detecting that the received light intensity of the reflected light is greater than 0 and lower than a predetermined threshold value.

In the state detection system of an aspect of the present invention, the wavelength of the monitoring light is a wavelength in a visible light band.

In the state detecting system of an optical fiber according to one aspect of the present invention, the monitoring light is a flat-top beam.

In the state detection system of an optical fiber according to one aspect of the present invention, the monitoring light and the cauterizing light have the same beam shape.

In the state detection system for an optical fiber according to one aspect of the present invention, a mechanism for cutting off a wavelength of the cauterizing light is provided on a front side of the light receiving unit.

Effect of invention

According to the present invention, the bending loss when the optical fiber is operated can be accurately measured, and the presence or absence of bending of the optical fiber can be determined.

Drawings

Fig. 1 is a schematic diagram showing a configuration example of an optical fiber state detection system according to a first embodiment of the present invention.

Fig. 2 is a diagram for explaining an example of the bending loss characteristics of the optical fiber, and is a graph showing a relationship between the wavelength of light and the bending loss of the optical fiber.

Fig. 3 is a schematic diagram showing a first configuration example for using monitoring light as a flat-top beam in the optical fiber condition detection system according to the first embodiment of the present invention.

Fig. 4 is a schematic diagram showing a second configuration example for using monitoring light as a flat-top beam in the optical fiber condition detection system according to the first embodiment of the present invention.

Fig. 5 is a graph for explaining an example of the bending loss characteristic of the optical fiber according to the core diameter of the optical fiber, and is a graph showing a relationship between the bending radius and the bending loss of the optical fiber.

Fig. 6 is a diagram showing an example of the apparatus configuration of example 1 of fig. 5.

Fig. 7 is a diagram showing an example of the apparatus configuration of example 2 of fig. 5.

Fig. 8 is a schematic diagram showing a configuration example of an optical fiber state detection system according to a second embodiment of the present invention.

Fig. 9 is a schematic diagram showing a configuration example for making the monitoring light and the cauterizing light have the same beam shape in the optical fiber state detection system according to the second embodiment of the present invention.

Fig. 10 is a schematic diagram showing a first configuration example of an optical fiber state detection system according to a third embodiment of the present invention.

Fig. 11 is a schematic diagram showing a second configuration example of an optical fiber state detection system according to a third embodiment of the present invention.

Fig. 12 is a schematic diagram showing a third configuration example of an optical fiber state detection system according to a third embodiment of the present invention.

Detailed Description

A state detection system for an optical fiber according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments. The components in the following embodiments include components that can be easily replaced by those skilled in the art, or substantially the same components.

(first embodiment)

As shown in fig. 1, an optical fiber state detection system (hereinafter, simply referred to as "state detection system") 1 according to the present embodiment includes a laser device 10, an optical fiber probe 30 including a reflection mechanism 31, a connector 40 for connecting the laser device 10 and the optical fiber probe 30, an optical fiber 50, a control unit 60, and a display unit 70. The connector 40 is not essential and may be omitted. In the figure, the optical fiber 50 is shown by a solid line.

The laser device 10 includes a monitor LD11, a monitor PD12, a tap coupler 13, and an optical fiber 50 connecting these components. In addition, "LD" denotes a laser diode, and "PD" denotes a photodiode.

The monitor LD11 is a light source (first light source) that outputs monitoring light TL for monitoring the state of the optical fiber 50. The monitor LD11 is connected to the input side of the tap coupler 13 via the optical fiber 50.

In the laser device 10, a plurality of monitor LDs 11 that output light having different wavelengths may be arranged. As the monitor LD11, an LD in which a plurality of LDs that output light of different wavelengths are grouped together may be used. The output of the monitor LD11 is set to, for example, 1mW or less. The wavelength of the monitoring light TL is set to a wavelength in a visible light range to a near infrared range (400nm to 1500nm), and preferably set to a wavelength in a visible light range (400nm to 700 nm).

Here, fig. 2 is a diagram for explaining an example of the bending loss characteristic of the optical fiber 50, and is a graph showing a relationship between the wavelength of light and the bending loss of the optical fiber 50. The bending loss is defined as, for example, an increase in transmission loss when the optical fiber 50 is bent at a predetermined bend radius.

As shown in fig. 2, the bending loss of the optical fiber 50 is small on the short wavelength side and large on the long wavelength side. This means that, for example, the bending loss of the optical fiber 50 is measured by the monitoring light TL of a short wavelength (visible light band), and when it is determined that "bending is present", even if the monitoring light TL of a long wavelength (a wavelength band longer than the visible light band) is used, it is determined that "bending is present".

Therefore, as described above, by using light in the visible light wavelength band as the monitoring light TL, it is possible to determine whether or not the optical fiber 50 is bent when the monitoring light TL in a wavelength band longer than the visible light wavelength band is used. Further, for example, when it is determined that "no bending" is present when monitoring light in the visible light wavelength band is used, and it is determined that "bending" is present when monitoring light in a wavelength band longer than the visible light wavelength band is used, it is also possible to use light in a wavelength band longer than the visible light wavelength band as the monitoring light TL, and thereby the bending loss can be estimated excessively.

The monitoring light TL is constituted by a flat top Beam (Tpo Hat Beam). In order to make the monitoring light TL a flat-topped beam, for example, as shown in fig. 3, a method of arranging the combiner 14 between the monitor LD11 and the tap coupler 13, a method of imparting a bend to the optical fiber 50 to perform mode mixing as shown by a circle in fig. 4, a method of applying vibration to the optical fiber 50, or the like is used.

In fig. 3 and 4, the optical fiber probe 30, the connector 40, the control unit 60, and the display unit 70 are not shown. The number of the combiners 14 shown in fig. 3 is not particularly limited, and may be two or more. The bending Radius of the optical fiber 50 shown in fig. 4 is set to a value (for example, r is 10mm) of a Long Term bending Radius (Long Term Bend Radius: LTBR) of the optical fiber 50. The remaining structure will be described with reference to fig. 1.

The monitor PD12 is a light receiving unit for receiving and monitoring the reflected light RL reflected by the reflection mechanism 31. The monitor PD12 is connected to the input side of the tap coupler 13 via the optical fiber 50. Further, a plurality of monitors PD12 may be arranged similarly to the monitor LD11, and for example, a plurality of monitors PD12 may be configured to receive light of different wavelengths output from the plurality of monitor LDs 11.

The tap coupler 13 is disposed between the monitor LD11 and the monitor PD12, and the reflection mechanism 31. The monitor LD11 and the monitor PD12 are connected to the input side of the tap coupler 13 via the optical fiber 50. Further, a connector 40 is connected to the output side of the tap coupler 13. The tap coupler 13 is preferably an asymmetric tap coupler, and the combining ratio thereof can be set to, for example, 99: 1. 95: 5. 90: 10. 75: 25, and the like. Further, in fig. 1, the ratio of the input port to the output port of the tap coupler 13 is 2: 1, or 2: 2.

the reflecting mechanism 31 reflects the monitoring light TL propagating in the optical fiber 50. The reflection mechanism 31 is composed of, for example, an FBG (fiber bragg grating) or a reflection film, and is provided on the distal end side of the optical fiber 50 in the optical fiber probe 30. When the reflection mechanism 31 is formed of a reflection film, the reflection mechanism 31 is preferably provided at the distal end of the optical fiber 50. When the reflection mechanism 31 is formed of an FBG, the reflection mechanism 31 is preferably provided slightly inside the distal end of the optical fiber 50.

The monitoring light TL that propagates toward the distal end side of the optical fiber 50 and is reflected by the reflection mechanism 31 propagates back toward the proximal end side of the optical fiber 50 as reflected light RL. The reflected light RL is input to the monitor PD12 via the connector 40 and the tap coupler 13.

The optical fiber 50 is, for example, a multimode optical fiber. The optical fiber 50 is, for example, a step index type optical fiber having a core diameter of 105 μm/a cladding diameter of 125 μm and including a coating such as an acrylate coating or a polyimide coating.

The core diameter of the optical fiber 50 on the laser device 10 side (hereinafter referred to as the "device side") and the core diameter of the optical fiber 50 on the fiber probe 30 side (hereinafter referred to as the "probe side") may be different from each other. In this case, the core diameter of the optical fiber 50 on the device side is preferably smaller than the core diameter of the optical fiber 50 on the probe side.

Here, fig. 5 is a diagram for explaining an example of the bending loss characteristic of the optical fiber 50 according to the core diameter of the optical fiber 50, and is a graph showing a relationship between the bending radius of the optical fiber 50 and the bending loss. In example 1 of the figure, as shown in fig. 6, for example, the following device configuration is assumed: a light source is provided on the device side, a power meter is provided on the probe side, the core diameter of the optical fiber 50 on the device side is 105 μm, and the core diameter of the optical fiber 50 on the probe side is 150 μm. In example 1, for example, it is assumed that a cauterization LD described later is disposed instead of the cauterization-type light beam of the monitor LD11 in fig. 1.

In example 2 of fig. 5, for example, as shown in fig. 7, the following device configuration is assumed: a light source is provided on the device side, a power meter is provided on the probe side, the core diameter of the optical fiber 50 on the device side is 105 μm, the core diameter of the optical fiber 50 between the two connectors 40 on the probe side is 150 μm, and the core diameter of the optical fiber 50 between the connector 40 on the probe side and the power meter is 105 μm. In example 2, a ray of the reflection monitoring type shown in fig. 1 is assumed. In example 3 of fig. 5, for example, an apparatus configuration is assumed in which the core diameters of the optical fibers 50 on the apparatus side and the probe side are both 105 μm in fig. 6.

As shown in fig. 5, when the core diameters of the optical fiber 50 on the device side and the optical fiber 50 on the probe side are different (reference examples 1 and 2) and the core diameters thereof are the same (reference example 3), it is found that the bending loss becomes larger and more sensitive to the bending loss. Therefore, by changing the core diameter of the optical fiber 50 between the device side and the probe side, the apparent bending loss increases, and the occurrence of bending of the optical fiber 50 becomes easier to detect. When the core diameters of the device-side and probe-side optical fibers 50 are different, it is necessary to correct the difference between the apparent bending loss and the real-time bending loss by using, for example, a correspondence table.

The control unit 60 includes a not-shown arithmetic unit and a storage unit. The arithmetic Unit performs control executed by the control Unit 60 and various arithmetic processes for realizing the functions of the control Unit 60, and is configured by, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or both of the CPU and the FPGA. Further, the storage unit includes: a part configured by a ROM (Read Only Memory) storing various programs, data, and the like used by an arithmetic unit for arithmetic processing; and a RAM (Random Access Memory) used for storing a work space when the arithmetic unit performs arithmetic processing, a result of the arithmetic processing performed by the arithmetic unit, and the like.

Further, the control unit 60 includes: an input unit (not shown) that receives an input of a current signal or the like from the monitor PD 12; and an output unit (not shown) that outputs a drive current to the monitor LD11, an instruction signal to the display unit 70, and various information based on the results of various arithmetic processes.

The display unit 70 is a part for displaying characters, symbols, and the like for outputting various information and notifying the outside to the operator of the laser apparatus 10, or for providing a warning by an alarm, and is configured by, for example, a liquid crystal display, in accordance with an instruction signal from the control unit 60.

In the state detection system 1 including the optical fiber having the above-described configuration, when detecting that the received light intensity of the reflected light RL received by the monitor PD12 is greater than 0 and lower than a predetermined threshold value, the control unit 60 outputs information indicating that the received light intensity has decreased to the outside. Specifically, the control unit 60 outputs information that the received light intensity has decreased to the display unit 70. In this case, the control unit 60 can determine that the optical fiber 50 in the optical fiber probe 30 is bent. The controller 60 may sound an alarm or the like on the display unit 70 to notify the outside (operator) of the decrease in the light reception intensity, that is, the occurrence of the bend in the optical fiber 50. As the predetermined threshold value, a value of the received light intensity attenuated by 10% or 1dB from the value of the received light intensity at the normal time can be set.

In addition, the control unit 60 may determine that the optical fiber 50 in the optical fiber probe 30 is bent even if the received light intensity of the reflected light RL is not lower than the predetermined threshold value, for example, when the change rate of the received light intensity of the reflected light RL within a certain period of time is large, such as when the received light intensity of the reflected light RL rapidly decreases within a short period of time.

According to the optical fiber state detection system 1 according to the first embodiment described above, the bending loss when the optical fiber 50 is operated can be accurately measured, and when the light receiving intensity of the reflected light decreases, information of the decrease in the light receiving intensity can be output, so that the presence or absence of bending of the optical fiber 50 can be determined.

(second embodiment)

As shown in fig. 8, the optical fiber state detection system 1 according to the present embodiment includes a laser device 10A, an optical fiber probe 30A, a connector 40 for connecting the laser device 10A and the optical fiber probe 30A, an optical fiber 50, a control unit 60, and a display unit 70. The configuration of the connector 40, the optical fiber 50, the control unit 60, and the display unit 70 in this figure is the same as that of the first embodiment (see fig. 1).

The laser device 10A includes a monitor LD11, a cauterization LD15, a combiner 16, a monitor PD12, a tap coupler 13, and an optical fiber 50 connecting these components. The optical fiber probe 30A further includes a reflection mechanism 3. The optical fiber probe 30A may further include a side irradiation mechanism that irradiates the cauterizing light TL2 transmitted through the reflection mechanism 31 while changing the traveling direction thereof to a different direction from the traveling direction before the transmission and reflection mechanism 31.

The monitor LD11 is a light source (first light source) that outputs monitoring light TL1 for monitoring the state of the optical fiber 50. The monitor LD11 is connected to the input side of the multiplexer 16 via the optical fiber 50. Further, the monitor PD12 is connected to the input side of the tap coupler 13 via the optical fiber 50.

In the laser device 10, a plurality of monitor LDs 11 that output light having different wavelengths may be arranged. For example, when two monitor LDs 11 are used, it is preferable that one monitor LD11 outputs light in a wavelength band shorter than the wavelength band of the cauterizing light TL2, and the other monitor LD11 outputs light in a wavelength band longer than the wavelength band of the cauterizing light TL 2. In this way, by outputting light having a shorter wavelength than the cauterizing light TL2 from one monitor LD11 and outputting light having a longer wavelength than the cauterizing light TL2 from the other monitor LD11, the accuracy of estimating the bending loss is further improved.

The cauterizing LD15 is a light source (second light source) that outputs cauterizing light TL 2. The burning LD15 is connected to the input side of the combiner 16 via the optical fiber 50. Here, when the laser device 10A is used for laser treatment using a medical catheter, the cauterizing light TL2 output from the cauterizing LD15 is light in a wavelength band called "window of living body", that is, light in a wavelength band of 600nm to 1500 nm. Further, the cauterizing light TL2 has a different wavelength from the monitoring light TL 1. The output of the cauterizing LD15 is set to, for example, 0.1W or more.

Here, the monitoring light TL1 and the cauterizing light TL2 preferably have the same beam shape. This is because the bending loss of the optical fiber 50 has mode dependency, and therefore, if the bending loss is measured by using light sources having different beam shapes, the value may change.

In order to make the beam shape of the monitor light TL1 the same as that of the cauterizing light TL2, the monitor light TL1 and the cauterizing light TL2 are multiplexed (synthesized) on the upstream side in the laser device 10B as in the laser device 10B shown in fig. 9, for example. The specific structure of the optical member 17 shown in the same drawing is not particularly limited, and may be, for example, a member constituted by an isolator, a filter, or another optical fiber. By making the monitor light TL1 and the cauterizing light TL2 have the same beam shape, the measurement error of the bending loss can be reduced.

The combiner 16 combines the monitoring light TL1 with the cauterizing light TL 2. The multiplexer 16 is constituted by, for example, a WDM (wavelength division multiplexing) coupler, a combiner, a tap coupler, a spatial coupling optical system, or the like. The combiner 16 is connected to the input side of the tap coupler 13 via an optical fiber 50.

The reflection means 31 is composed of, for example, an FBG or a reflection film, reflects the monitoring light TL1, transmits the cauterizing light TL2, and irradiates the cauterizing light TL2 to the outside.

In the state detection system 1A including the optical fiber having the above-described configuration, when the control unit 60 detects that the received light intensity of the reflected light RL received by the monitor PD12 is greater than 0 and lower than a predetermined threshold value, it outputs information indicating that the received light intensity has decreased to the outside. Specifically, the control unit 60 outputs information that the received light intensity has decreased to the display unit 70. In this case, the control unit 60 can determine that the optical fiber 50 in the optical fiber probe 30A is bent. The controller 60 may sound an alarm or the like on the display unit 70 to notify the outside (operator) that the light reception intensity has decreased, that is, the occurrence of bending of the optical fiber 50. Alternatively, the controller 60 may stop the output of the cauterizing light TL2 by turning off the cauterizing LD 15. The predetermined threshold value can be set in the same manner as in the first embodiment.

According to the optical fiber state detection system 1A according to the second embodiment described above, the bending loss when the optical fiber 50 is operated can be accurately measured, and when the light receiving intensity of the reflected light decreases, information that the light receiving intensity has decreased can be output, and the presence or absence of bending of the optical fiber 50 can be determined. Further, according to the state detection system 1A, when the optical fiber 50 is bent, the cauterizing LD15 is closed to stop the output of the cauterizing light TL2, thereby suppressing cauterization of unnecessary parts.

(third embodiment)

In the optical fiber state detection system according to the present embodiment, a mechanism for cutting off the wavelength of the cauterizing light TL2 is provided on the near side of the monitor PD 12. Three configuration examples of the present embodiment will be described below with reference to fig. 10 to 12. In these drawings, the optical fiber probe 30A and the connector 40 are not shown.

< first configuration example >

As shown in fig. 10, the laser device 10C of the optical fiber state detection system 1C as the first configuration example includes a light source 18, a monitor PD12, a cauterizing light cut-off mechanism 19, and a tap coupler 13. The configurations of the monitor PD12 and the tap coupler 13 in the same manner as in the first embodiment (see fig. 1) are the same.

The light source 18 outputs monitoring light TL1 and cauterizing light TL 2. The light source 18 is connected to the input side of the tap coupler 13 via an optical fiber 50. The monitor PD12 is connected to the cauterizing light cut-off mechanism 19 via the optical fiber 50.

The cauterizing light cut-off mechanism 19 is disposed between the monitor PD12 and the tap coupler 13. The cauterizing light cut-off mechanism 19 is constituted by, for example, a filter, a WDM coupler, and the like. Here, for example, when the optical fiber 50 of the optical fiber probe 30A is moved while the monitoring light TL1 and the cauterizing light TL2 are simultaneously output from the light source 18, a part of the cauterizing light TL2 may propagate toward the monitor PD 12. If the monitor PD12 has light receiving sensitivity even at the wavelength of the cauterizing light TL2, when the cauterizing light TL2 covers the monitoring light TL1 and is input to the monitor PD12, only the reflected light RL due to the monitoring light TL1 cannot be appropriately received by the monitor PD12, and a measurement error occurs in the bending loss. Therefore, by disposing the cauterizing light cut-off mechanism 19 on the near side of the monitor PD12, only light of a specific wavelength (reflected light RL due to the monitoring light TL 1) can be input to the monitor PD 12.

< second configuration example >

As shown in fig. 11, the laser device 10D of the optical fiber state detection system 1D as the second configuration example includes a light source 18, a monitor PD12, a cauterization PD20, a cauterization light cut-off mechanism 19, and tap couplers 13A and 13B. The light source 18, the monitor PD12, and the cauterizing light cut-off mechanism 19 in the figure are configured in the same manner as in the first configuration example (see fig. 10).

The light source 18 is connected to the tap coupler 13B via an optical fiber 50. The monitor PD12 is connected to the cauterizing light cut-off mechanism 19 via the optical fiber 50. Further, the cautery PD20 is connected to the tap coupler 13A via the optical fiber 50.

The tap coupler 13A branches the return light from the tap coupler 13B side into a first return light RL1 and a second return light RL 2. Here, the return light includes a part of the monitoring light TL1 reflected by the not-shown reflection mechanism 31 and the cauterizing light TL 2. The tap coupler 13A outputs the first return light RL1 to the cauterizing light cut-off mechanism 19 and the second return light RL2 to the cauterizing PD20 through the optical fiber 50. The output side of the tap coupler 13A is connected to the input side of the tap coupler 13B via an optical fiber 50.

As described above, by disposing the burning light cut-off mechanism 19 on the near side of the monitor PD12, only light of a specific wavelength (first return light RL1) can be input to the monitor PD 12. The intensity of light received by the cauterizing PD20 can be used to measure the intensity of the cauterizing light TL 2.

< third structural example >

As shown in fig. 12, a laser device 10E of an optical fiber state detection system 1E as a third configuration example includes a light source 18, a monitor PD12, a cauterizing PD20, a WDM coupler 21, and a tap coupler 13B. The configurations of the light source 18, the monitor PD12, the burn PD20, and the tap coupler 13B in this figure are the same as those of the second configuration example (see fig. 11).

The light source 18 is connected to the tap coupler 13B via an optical fiber 50. Further, the monitor PD12 is connected to the WDM coupler 21 via the optical fiber 50. Further, the cauterizing PD20 is connected to the WDM coupler 21 via the optical fiber 50.

The WDM coupler 21 demultiplexes the first return light RL1 and the second return light RL 2. The WDM coupler 21 outputs a first return light RL1 to the monitor PD12 and a second return light RL2 to the cauterizing PD20 via the optical fiber 50. The output side of the WDM coupler 21 is connected to the input side of the tap coupler 13B via the optical fiber 50.

As described above, by disposing the WDM coupler 21 on the near side of the monitor PD12 and the burn-in PD20, only the light of a specific wavelength (the first return light RL1 and the second return light RL2) can be input to the monitor PD12 and the burn-in PD 20.

The optical fiber bend detection system according to the embodiment of the present invention has been specifically described above by way of the embodiment for carrying out the present invention, but the gist of the present invention is not limited to these descriptions, and it is necessary to be broadly construed based on the descriptions of the claims. It is to be understood that the configuration of the present invention, which is variously modified or changed based on the above description, is also included in the gist of the present invention.

For example, in the above-described embodiment, the description has been given assuming that the laser devices 10, 10A, 10B, 10C, 10D, and 10E are used for a medical catheter or the like, but the applications of the laser devices 10, 10A, 10B, 10C, 10D, and 10E are not limited to medical use.

In the above-described embodiment, the example in which the reflection mechanism 31 is provided at the distal end of the optical fiber 50 in the optical fiber probe 30 has been described, but the reflection mechanism 31 may be provided between the distal end and the proximal end of the optical fiber 50 in the optical fiber probe 30 (halfway). This makes it possible to determine whether or not the optical fiber 50 is bent at the position where the reflection mechanism 31 is provided.

Industrial applicability

The present invention is preferably applied to bending detection of an optical fiber used for a medical optical fiber probe.

-description of symbols-

1. 1A, 1C, 1D, 1E state detection system

10. 10A, 10B, 10C, 10D, 10E laser device

11 LD for monitor

12 monitor PD

13. 13A, 13B tap coupler

14 synthesizer

15 LD for cauterization

16 wave combiner

17 optical component

18 light source

19 cauterization light cut-off mechanism

20 cauterizing PD

21 WDM coupler

30. 30A optical fiber probe

31 reflection mechanism

40 connector

50 optical fiber

60 control part

And 70, a display part.