JP3403773B2 - Fiber connection unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber connecting unit for optically connecting a fiber and a fiber or a laser oscillator and a fiber when transmitting a processing laser beam such as a YAG laser beam through the fiber.

[0002]

2. Description of the Related Art A conventional fiber connecting unit is shown in FIG.
Shown in. In FIG. 5 , reference numeral 1 is an emitting fiber that transmits the laser light from the oscillator and emits the laser light from the end, and reference numeral 2 is an incident fiber that enters the laser light emitted from the emitting fiber. Output fiber 1
And the input fiber 2 are linearly spaced apart,
Between the emission fiber 1 and the incidence fiber 2, the laser light emitted from the emission fiber 1 is incident on the incidence fiber 2
A condenser lens unit 3 for condensing light on the incident end face of is installed.

In this structure, there is no adjusting mechanism for adjusting the mutual positions of the outgoing fiber 1 and the incoming fiber 2, and the outgoing fiber 1 and the incoming fiber 2 are fixedly fixed. Further, the power of the laser light emitted from the emission fiber 1 is unknown at this time, and it is also unknown whether the optical transmission state is normal or abnormal.

[0004]

Therefore, the above-mentioned prior art has the following problems. (1) Since there is no mechanism for adjusting the tip position of the incident fiber 2 while monitoring the incident state of the laser light on the end face of the incident fiber 2, the condensing point of the laser light by the condensing lens unit 3 is set to the incident end face of the incident fiber 2. It is difficult to position it exactly in the center of the. (2) Laser light is transmitted from the oscillator through a fiber of 200 m, for example, and the intermediate transmission power cannot be confirmed when transmitting the laser light to the next fiber through the fiber connection unit. It is unknown whether the transmission is stable.

The present invention has been made in consideration of the above point, and when the processing laser light such as the YAG laser light is transmitted through the fiber, the fibers are well connected and
It is an object of the present invention to provide a fiber connection unit capable of confirming the power of laser light at this connection point and stably transmitting the laser light to the processing point.

[0006]

That is, according to the present invention, in a fiber connection unit for optically connecting a first fiber and a second fiber for transmitting a laser beam for processing, the light is emitted from the end face of the first fiber. And a condenser lens unit for condensing the laser light on the incident end face of the second fiber, and guiding the laser light emitted from the end face of the first fiber to the second fiber, and part of the laser light. A semi-transmissive bender that transmits the semi-transmissive bender, and an emission light monitoring unit that detects the laser light that has passed through the semi-transmission bender and measures the power of the laser light emitted from the end face of the first fiber based on the detection result. This outgoing light
Based on the detection result from the niter means,
Laser light adjusting means for controlling the light source and adjusting the laser light output
And an incident end face monitor means for displaying an end face image and its brightness by irradiating the incident end face of the second fiber with visible light and inputting the reflected light through a semi-transparent bender. .

In this structure, preferably, an indirect cooling means for cooling the respective holding portions respectively holding the exit end of the first fiber, the condenser lens unit and the entrance end of the second fiber, and the second further comprising an adjustment table for holding the holding portion of the entrance end of the fiber to be movable in three axial directions, the temperature detection means to detect a condensing lens unit and the temperature of the semipermeable vendors.

The present invention also provides a fiber connection unit for optically connecting a laser oscillator that oscillates a processing laser beam and a fiber that transmits the processing laser beam,
A condenser lens unit that collects the laser light emitted from the laser oscillator on the incident end face of the fiber, and a semi-transmission that reflects the laser light emitted from the laser oscillator to the fiber and transmits a part of the laser light. With a vendor,
Detecting the laser beam transmitted through the semitransparent vendors, and the emitted light monitoring means for measuring the power of the laser beam emitted from the laser oscillator on the basis of the detection result, the emitted
Laser oscillator based on the detection result from optical monitoring means
Light adjustment to control the power supply of the laser and adjust the output of laser light
And an incident end face monitor for displaying an end face image and its brightness by irradiating the incident end face of the fiber with visible light and inputting the reflected light through a semi-transparent bender.

Also in this configuration, preferably, the indirect cooling means for cooling the condenser lens unit and each holding portion for holding the incident end portion of the fiber, and the holding portion for the incident end portion of the fiber are moved in three axial directions. It further comprises an adjustment table which is held as much as possible, and a temperature detecting means which detects each temperature of the condenser lens unit and the semi-transparent bender.

[0010]

In the above structure, the semi-transmissive bender reflects most of the laser light emitted from the emitting end toward the incident fiber and transmits a part of the laser light to the laser light sensor of the emitted light monitor means. . The emitted light monitor means
A laser light sensor and a laser light power indicator are provided, and the power of the laser light emitted from the emitting end is calculated from the detection value of the laser light sensor and displayed on the laser light power indicator. By monitoring the power of the emitted laser light and adjusting the output of the oscillator, the laser light can be stably supplied to the processing point.

The incident end face monitor means includes an illuminating lamp for irradiating the incident end face of the fiber with visible light, a semi-transparent device for reflecting the visible light from the illuminating lamp toward the incident end face and transmitting the visible light reflected from the incident end face. Transparent mirror,
A camera that inputs reflected light from the incident end face to capture an image of the end face, an imaging lens unit that collects reflected light from the incident end face to the camera, and a TV monitor that displays the end face image captured by the camera. An image of the end face of the fiber, on which the laser light emitted from the emission end, condensed by the condensing lens unit, and bent by the semi-transmissive bender is incident, is captured by the illumination of the illumination lamp and displayed on the TV monitor. Therefore, by adjusting the position of the tip of the fiber with the adjustment table while watching the TV monitor, it is possible to accurately position the focal point of the laser light at the center of the incident end face of the fiber. Further, during the processing, it is possible to stabilize the processing by monitoring the fluctuation of the reflected light from the processing point.

Further, by cooling the periphery of the optical component by the indirect cooling means, it is possible to suppress the temperature rise of the optical component due to the increase in the output of the laser beam, and the temperature of the optical component is measured by the temperature detecting means. By doing so, it is possible to improve the reliability of the fiber connecting unit by monitoring the temperature change of the optical component.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same parts as those of the conventional example will be described with the same reference numerals. FIG. 1 shows an embodiment of the fiber connecting unit of the present invention. In this example,
The exit fiber (first fiber) 1 and the entrance fiber (second fiber) 2 are connected in an L shape. The fiber connection unit 10 of the present embodiment includes a condenser lens unit 3 including two lenses that transmits and condenses the laser light 11 emitted from the emission fiber 1, and a laser light transmitted through the condenser lens unit 3. 11 in front of the condensing point 9
A semi-transmissive bender 12 made of quartz or the like that folds back to 0 degrees , a laser light sensor 13 that detects a few% of the laser light that has passed through the semi-transmissive bender 12, and the laser light power detected and measured by the laser light sensor 13 are displayed. The laser light power indicator 14, the illumination lamp 15 and the semi-transmissive mirror 16 for applying light to the end face of the incident fiber 2, and the light 17 reflected from the end face of the incident fiber 2 are input and an image of the end face is captured. It is composed of a CCD camera 18, an imaging lens unit 19 for converging the reflected light 17 from the end face of the incident fiber 2 to the CCD camera 18, and a TV monitor 20 for inputting and displaying an image signal from the CCD camera 18. ing.

Further, this fiber connection unit 10
In, the cooling layer 21 that indirectly cools the end face of the output fiber 1, the condenser lens unit 3 and the end face of the input fiber 2 is formed on each side surface. Further, thermocouples 22 are attached to the end surfaces of the condenser lens unit 3 and the semi-transmissive bender 12, respectively, and the temperature is measured by a thermometer 23. Further, a holding portion 24 for holding the end face of the incident fiber 2 and having the cooling layer 21
Is an X-axis table 25a movable in the X-axis direction and a Y-axis table 25b Z movable in the Y-axis direction as shown in FIG.
It is installed on an adjustment table 25 that is movable in the three axial directions and is composed of a Z-axis table 25c that is movable in the axial direction, and is adjusted so that the center of the end face of the incident fiber 2 is located at the focal point of the laser light. . Also, the fiber connection unit 1
Data obtained from 0 (temperature, end face image, power)
As shown in FIG. 2, each measuring instrument inputs to the computer 26, and the computer 26 controls the power supply 27 of the oscillator based on each data.

Next, the operation of the fiber connecting unit having the above structure will be described. The laser light 11 emitted from the emission fiber 1 that transmits the laser light from the oscillator is condensed by the condenser lens unit 3 composed of several condenser lenses, and the laser light 11 is divided into half before being condensed on the end face of the incident fiber 2. Transparent vendor 1
It is folded back 90 degrees at 2 and is focused on the end face of the incident fiber 2 which is installed in the direction perpendicular to the output fiber.
At this time, several percent of the laser light transmitted through the semi-transmissive bender 12 is input to the laser light detection sensor 13, and the power of the laser light 11 emitted from the emission fiber 1 is measured.
The end surface of the incident fiber 2 is irradiated with the visible light reflected by the semitransparent mirror 16 from the illumination lamp 15. The light 17 that is emitted to and reflected from the incident end face is the semi-transparent bender 1
The light passes through 2 and is focused on the CCD camera 18 by the imaging lens unit 19. The CCD camera 18 inputs the light 17 that is converged by the imaging lens unit 19 and transmitted through the semi-transmissive mirror 16, and captures an end face image. CCD camera 1
The image of the incident end face captured by the TV monitor 2
Displayed at 0.

The computer 26 inputs the end face image data from the TV monitor 20 via the image processing device 28, and also inputs the data from the thermometer 23 and the laser light power display meter 14 to judge each data and make an oscillator. It controls the power source 27 and so on.

Specifically, it is judged whether or not the power is normal based on the data obtained from the laser light power indicator 14, and if the power is small, the output of the power supply 27 is increased to stabilize the power. Take control. Further, it is determined whether the data obtained from the thermometer 23 is normal or abnormal, and if abnormal, the power supply 27 stops the laser oscillation. Further, the alignment is adjusted by the TV monitor 20 which monitors the end face of the fiber, and visible light generated during processing is observed on this monitor through the fiber 2.
The brightness of this visible light fluctuates greatly when it is abnormal. While comparing this amount of change in brightness with conventional data,
The laser output is controlled by a computer.

As is clear from the above description, the fiber connection unit of this embodiment has the following effects, and is therefore suitable for laser processing, repair, etc., particularly in a nuclear power plant requiring high reliability. is there. (1) The optical axis of the fiber can be easily adjusted,
Fiber can be easily replaced. (2) Since the power incident on the second stage fiber can be measured, stable processing can be performed, and by comparing it with the oscillator output, it is possible to assume the deterioration of the fiber and optical components of the previous stage, and the overall system The reliability of can be increased. Further, since optical feedback control to the power source can be easily performed, more stable processing can be performed. (3) Deterioration of optical parts in the fiber connection unit,
Since the damage status can be determined, a highly reliable optical transmission system can be constructed.

FIG. 3 shows another embodiment of the fiber connecting unit of the present invention. The arrangement of the semi-transmissive bender 12 and the condenser lens unit 3 is different from that of the embodiment shown in FIG. Is. That is, about 99% of the laser light emitted from the emission fiber 1 is reflected by the semi-transmissive bender 12, passes through the condenser lens unit 3, and is condensed on the end face of the incident fiber 2. Semi-transparent bender 1
A part of the laser light transmitted through 2 is input to the laser light sensor 13 through the laser light imaging lens 31, the power of the emitted laser light is measured, and the power is displayed on the power indicator 14.
Further, in order to adjust the end face of the incident fiber 2, the illumination lamp 15, the semi-transmissive mirror 16 and the imaging lens unit 19 for forming an image of the end face of the incident fiber 2 and the CCD camera on the same optical axis as the incident fiber 2. 18 are installed. The difference between this embodiment and the embodiment shown in FIG. 1 described above is that they are functionally almost the same except that this embodiment is more difficult in terms of optical design.

FIG. 4 shows still another embodiment of the fiber connecting unit of the present invention, in which the laser oscillator 41 and the fiber are connected. In this example,
A laser beam 42 oscillated from several laser oscillators 41 arranged in series is returned by the two semi-transmissive benders 12a and 12b, condensed by the condenser lens unit 3, and incident on the incident fiber 2.

In this configuration, the semi-transparent bender 12b
A laser light sensor 13 is installed on the back side of the and the power is monitored. Further, a semi-transmissive mirror 16, an illumination lamp 15, and a CCD camera 18 are installed on the same optical axis as the incident fiber 2 for fiber end face monitoring.

With this configuration, the power constantly monitored by the laser light sensor 13 is input to the computer 26 and fed back to the power source 27 of the laser oscillator 41 to stabilize the laser processing. Further, the alignment of the end face of the incident fiber 2 can be easily performed by the fiber end face monitor, and the behavior and change of visible light that can be monitored during processing can be controlled by the computer 26 through the image processing device 28 by the computer 26.

[0023]

As described above, according to the present invention, the following effects can be obtained. (1) When adjusting the fiber and the optical axis of the fiber,
The optical axis of the incident fiber can be easily adjusted while observing the monitor screen, and the fiber can be easily replaced. (2) Stable processing can be performed by measuring the power incident on the second-stage fiber, and deterioration of the previous-stage fiber and optical components can be assumed by comparing with the output of the oscillator. The reliability as a whole can be improved. Further, since optical feedback control to the power source can be easily performed, more stable processing can be performed. (3) Deterioration of optical parts in the fiber connection unit,
Since the damage status can be determined, a highly reliable optical transmission system can be constructed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a fiber connection unit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing signal / data processing of the fiber connection unit according to the embodiment of the present invention.

FIG. 3 is a diagram schematically showing a fiber connecting unit according to another embodiment of the present invention.

FIG. 4 is a view schematically showing a fiber connection unit according to still another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional fiber connection unit.

[Explanation of symbols]

1 ... Output fiber 2 ... Incident fiber 3 ... Condensing lens unit 12 ... Semi-transparent bender 13 ... Laser light sensor 16 ... Semi-transparent mirror 18 ... CCD camera 19 ………… Imaging lens unit 20 ……… TV monitor 21 ... Cooling layer 25 ……… Adjustment table 41 ... Laser oscillator

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-150145 (JP, A) JP-A-60-108190 (JP, A) Actual opening Sho-58-111181 (JP, U) Actual opening Sho-63- 122784 (JP, U) Actual Kaihei 5-15010 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/32

Claims (8)

(57) [Claims] 1. A fiber connection unit for optically connecting a first fiber and a second fiber for transmitting a processing laser beam, wherein the laser beam emitted from the end face of the first fiber is the second fiber. A condensing lens unit that condenses on the incident end face of the fiber, and a semi-transmissive that reflects the laser light emitted from the end face of the first fiber and guides it to the second fiber, and transmits a part of the laser light. A bender, emission light monitor means for detecting the laser light transmitted through the semi-transmissive bender, and measuring the power of the laser light emitted from the end face of the first fiber based on the detection result, and the emission light monitor. Based on the detection result from the means
Controls the power of the laser oscillator connected to the first fiber
Laser light adjusting means for adjusting the output of the control laser light, and an end face image and its brightness by irradiating the incident end face of the second fiber with visible light and inputting the reflected light through the semi-transmission bender. An incident end face monitor means for displaying the above. 2. An indirect cooling means is provided for cooling each holding portion that holds the exit end of the first fiber, the condenser lens unit, and the entrance end of the second fiber, respectively. The fiber connection unit according to claim 1. 3. The fiber connecting unit according to claim 1, further comprising an adjustment table for holding a holding portion at an incident end portion of the second fiber so as to be movable in three axial directions. 4. The fiber connecting unit according to claim 1, further comprising temperature detecting means for detecting respective temperatures of the condenser lens unit and the semi-transparent bender. 5. A laser oscillator for oscillating processing laser light
Optically connect the fiber that transmits the laser light for processing
In the fiber connecting unit, the laser light emitted from the laser oscillator
A condenser lens unit that collects light on the incident end face of the bar, and a laser beam emitted from the laser oscillator
It guides the fiber and transmits a part of the laser light.
The semi-transparent bender and the laser light transmitted through this semi-transparent bender are detected.
The laser beam emitted from the laser oscillator is detected based on the detection result.
Emitted light monitoring means for measuring the power of the laser light, and the above-mentioned based on the detection result from the emitted light monitoring means.
Control the power of the laser oscillator and adjust the laser light output
Laser light adjusting means on the incident end face of the fiber
Visible light is emitted and the reflected light is transmitted through the semi-transmissive bender.
The edge image and its brightness are displayed by inputting
And an incident end face monitor means.
Fiber connection unit. 6. The condenser lens unit and the phi
Cooling each holding part that holds each entrance end of the bar
An indirect cooling means is provided, The claim 5 characterized by the above-mentioned.
Fiber connection unit. 7. The retaining portion of the entrance end portion of the front Symbol fiber triaxial
Provided with an adjustment table that holds it so that it can move in any direction.
The fiber connecting unit according to claim 5. 8. The condenser lens unit and the semi-transmission
Equipped with temperature detection means to detect the temperature of each sex vendor
The fiber connection unit according to claim 5, wherein
To.