CN115395348A - Fiber laser for simply monitoring output power - Google Patents

Fiber laser for simply monitoring output power Download PDF

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Publication number
CN115395348A
CN115395348A CN202211061568.5A CN202211061568A CN115395348A CN 115395348 A CN115395348 A CN 115395348A CN 202211061568 A CN202211061568 A CN 202211061568A CN 115395348 A CN115395348 A CN 115395348A
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CN
China
Prior art keywords
input port
laser
fiber
output
optical fiber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202211061568.5A
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Chinese (zh)
Inventor
张大鹏
邓剑钦
陆龙钊
程义
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ADVANCED FIBER RESOURCES (ZHUHAI) Ltd
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ADVANCED FIBER RESOURCES (ZHUHAI) Ltd
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Priority to CN202211061568.5A priority Critical patent/CN115395348A/en
Publication of CN115395348A publication Critical patent/CN115395348A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/0014—Monitoring arrangements not otherwise provided for
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering

Abstract

The invention provides an optical fiber laser for simply monitoring output power, which comprises a laser generator, an optical fiber coupler, an optical fiber end cap and a photoelectric receiver, wherein the laser generator is used for generating laser with preset power, the optical fiber coupler is provided with a first input port, a second input port and an output port, the first input port and the second input port are positioned on the same side, the first input port and the output port are positioned on two opposite sides, the first input port is connected with the laser generator, the optical fiber end cap is connected with the output port, and the photoelectric receiver is connected with the second input port. Reflected light generated by the optical fiber end cap is output from the second input port according to a certain proportion of splitting ratio and is input to the photoelectric receiver as optical power monitoring signal light, and then the output laser is monitored in real time by using simple optical path device arrangement.

Description

Fiber laser for simply monitoring output power
Technical Field
The invention relates to the field of lasers, in particular to a fiber laser capable of simply monitoring output power.
Background
Along with laser radar's rapid development, comparatively miniature fiber laser becomes laser radar's light source with its simple structure, efficient, the stable performance is reliable, advantages such as with low costs are preferred, and the fiber laser of the different grade type also widely uses in different fields certainly. Because the application scene of laser radar can involve crowds, high-intensity laser has potential safety hazard to human eyes, so the output intensity of the laser must be monitored in real time, the monitoring accuracy is high, and the laser cannot drift along with environmental conditions and time.
In the existing design, an optical branching element is generally connected in series with an output optical fiber, a small part of laser output energy is branched out and sent to a photoelectric detector for power monitoring, and most of laser energy is continuously output. The laser source configured by the laser radar is often short and high-peak laser pulse. The tapped laser must be a small fraction (about-50 dB) to avoid exceeding the linear region of the photodetector, and therefore two stages of tapping are often required, e.g., one stage is 0.1% and the other stage is 1% further to achieve the overall-50 dB attenuation.
The conventional fiber laser shown in fig. 1 mainly includes a seed light source, a fiber amplifier 111, a fiber isolator 112, a first 1 × 2 fiber coupler 113, a fiber end cap 114, a second 1 × 2 fiber coupler 115, and a photoelectric receiver 116, where a laser light source generated by the seed light source outputs laser with a preset power to the fiber isolator 112 after power amplification of the fiber amplifier 111, and then the laser is input to the first 1 × 2 fiber coupler 113, a light ratio of two ports of the first 1 × 2 fiber coupler 113 is 0.1%/99.9%,99.9% of output ends are connected with the fiber end cap 114 and output outwards, and 0.1% of output ends in the first 1 × 2 fiber coupler 113 are connected with input ends of the second 1 × 2 fiber coupler 115. The optical ratio of the two ports of the second 1 × 2 optical fiber coupler 115 is 1%/99%, 1% of the output ends of the second 1 × 2 optical fiber coupler 115 are connected to the photoelectric receiver 116, and then 0.1% of the split light is incident to the photoelectric receiver as-50 dB attenuated light attenuated to 0.001% after being split by 1%. The laser adopts a relatively complex optical path to arrange a link, so that the cost is relatively high, and the insertion loss introduced is increased.
Moreover, power monitoring can be performed by using a fiber laser as shown in fig. 2, the fiber laser mainly includes a seed light source, a fiber amplifier 121, a fiber isolator 122, a 1 × 2 fiber coupler 123 and a photoelectric receiver 124, the laser light source generated by the seed light source outputs laser with preset power to the fiber isolator 122 after the power of the fiber amplifier 121 is amplified, and then the laser is input to the 1 × 2 fiber coupler 123, the optical ratio of two ports of the 1 × 2 fiber coupler 123 is 0.001%/99.999%, 0.001% of output ends in the 1 × 2 fiber coupler 123 are connected with the photoelectric receiver 124, and then the light attenuated to 0.001%, namely-50 dB attenuated light, is incident to the photoelectric receiver.
But since the light splitting is performed by only one-50 dB optical fiber coupler, the 50dB optical fiber coupler is difficult to be accurate, and the general error is ± 3-5dB. The main reason is that the fiber coupler is the mutual coupling generated by the gradual approach of the core waveguides of the two fibers through high-temperature melting, and the longer the coupling area of the two cores is, the higher the coupling strength is. However, the lower the coupling ratio, the more sensitive the change of the coupling ratio to the coupling length of the optical core, referring to the graph shown in fig. 3, the higher the sensitivity of the slope at-50 dB is, and the smaller the slope at-30 dB is, so the sensitivity is relatively small, therefore the 50dB optical fiber coupler and the optical fiber coupler with relatively large attenuation ratio are sensitive to the external environment, are easily affected by the temperature or stress change, and have poor stability, and the change is often irregular, which directly causes the error of energy monitoring.
Disclosure of Invention
The invention aims to provide a fiber laser for simply monitoring output power.
In order to achieve the purpose of the invention, the invention provides an optical fiber laser for simply monitoring output power, which comprises a laser generator, a 2 × 1 optical fiber coupler, an optical fiber end cap and an optical receiver, wherein the laser generator is used for generating laser with preset power, the 2 × 1 optical fiber coupler is provided with a first input port, a second input port and an output port, the first input port and the second input port are positioned on the same side, the first input port and the output port are positioned on two opposite sides, the first input port is connected with the laser generator, the optical fiber end cap is connected with the output port, and the optical receiver is connected with the second input port.
According to the scheme, the return loss of the optical fiber end cap is ingeniously utilized by utilizing weak reflected light existing when the optical fiber end cap outputs laser in the forward direction, the return loss of the optical fiber end cap is ingeniously utilized and is connected with a laser generator through a first input port of a 2 x 1 optical fiber coupler, then laser with preset power can be input into the optical fiber end cap from an output port 100%, the reflected light generated at the optical fiber end cap is output from the output port, the reflected light is output from a second input port according to a splitting ratio preset by the first input port and the second input port according to the splitting ratio of a certain proportion and is input into a photoelectric receiver as optical power monitoring signal light, and then a simple optical path device is used for arrangement.
Still further, the splitting ratio at the second input port is between 0.1% and 1%.
Still further, the return loss of the optical fiber end cap is between 30dB and 50 dB.
In a further aspect, the splitting ratio of the second input port is 1% and the return loss of the optical fiber end cap is 30dB.
From the above, a user can select different optical fiber end caps according to different laser output requirements, different optical fiber end caps have different return loss, and a proper splitting ratio of the second input port is selected according to the laser power of the optical fiber laser and the monitoring interval of the photoelectric receiver, preferably, when the return loss of the optical fiber end cap is 30dB, namely 0.1% of reflected light returns, the reflected light is output in a splitting mode through the second input port with the splitting ratio of 1%, so that light attenuated to 0.001%, namely-50 dB attenuated light, enters the photoelectric receiver, the linear monitoring interval of the photoelectric receiver is met, and monitoring accuracy is improved.
In a further aspect, the fiber laser further includes a fiber isolator connected between the first input port and the laser generator.
As can be seen from the above, the emitted light can be prevented from returning to the laser generator by the isolation of the fiber isolator, so as to protect the laser generator.
In order to achieve the object of the present invention, the present invention further provides a fiber laser for simply monitoring output power, including a laser generator, a 2 × 2 fiber coupler, a first fiber end cap, and a photoelectric receiver, wherein the laser generator is configured to generate laser with a preset power, a splitting ratio of the 2 × 2 fiber coupler is 50%, the 2 × 2 fiber coupler is provided with a first input port, a second input port, a first output port, and a second output port, the first input port and the second input port are located on a same side, the first output port and the second output port are located on a same side, the first input port and the first output port are located on opposite sides, the first input port is connected to the laser generator, the first fiber end cap is connected to the first output port, and the photoelectric receiver is connected to the second input port.
In a further aspect, the fiber laser further includes a second fiber end cap, and the second fiber end cap is connected to the second output port.
Still further, the first fiber end cap has a return loss between 45dB and 60 dB.
In a further aspect, the fiber laser further includes a fiber isolator connected between the first input port and the laser generator.
From the above, the optical fiber laser can also adopt a 2 × 2 optical fiber coupler to output 50% of the split laser light, the output port can be selectively provided with an optical fiber end cap, weak reflected light generated by the optical fiber end cap is output from the output port, then the reflected light is output from the second input port according to the splitting ratio and is input to the photoelectric receiver as optical power monitoring signal light, and then the arrangement of the simple optical path devices is utilized to realize the real-time monitoring of the first output port and/or the second output port.
Drawings
Fig. 1 is a prior art optical path diagram of a fiber laser.
Fig. 2 is an optical path diagram of another fiber laser of the prior art.
FIG. 3 is a graph of the Tap ratio of a prior art fiber coupler versus the length of the fiber coupling region.
Fig. 4 is an optical path diagram of a first embodiment of the fiber laser of the present invention.
Fig. 5 is an optical path diagram of a second embodiment of the fiber laser of the present invention.
The invention is further described with reference to the following figures and examples.
Detailed Description
First embodiment of fiber laser:
referring to fig. 4, the fiber laser includes a laser generator including a seed light source (not shown) and a fiber amplifier 21, a fiber isolator 22, a 2 × 1 fiber coupler 23, a fiber end cap 24, and a photo receiver 25, the laser source generated by the seed light source outputs laser light of a predetermined power to the fiber isolator 22 after power amplification of the fiber amplifier 21, and the fiber isolator 22 prevents return light from returning into the laser generator. The photo receiver 25, also called a photo detector, can convert the optical signal into an electrical signal, and then detect the optical power.
The 2 × 1 optical fiber coupler 23 is provided with a first input port, a second input port and an output port, the first input port and the second input port are located on the same side, the first input port and the output port are located on opposite sides, in this embodiment, the 2 × 1 optical fiber coupler 23 is a 1% optical fiber coupler, the splitting ratio of the first input port and the second input port is 99%/1%, the first input port is connected with the optical fiber isolator 22, the optical fiber end cap 24 is connected with the output port of the 2 × 1 optical fiber coupler 23 through an optical fiber, the photoelectric receiver 25 is connected with the second input port of the 2 × 1 optical fiber coupler 23, and the length of the optical fiber can be adjusted according to actual requirements.
Laser with preset power is input from a first input port, and then is output from an output port to an optical fiber End cap 24, and then is output from the optical fiber End cap 24, the optical fiber End cap (End Caps) is a high-power device designed according to a high-power optical fiber laser and an optical fiber amplifier for processing an output End face, so that the output End face of an ordinary optical fiber End cap is subjected to certain output beam expanding processing to reduce the optical power density of the output End, so that a tiny echo reflection will be generated at the End face, and the echo loss is generally between 30dB and 50dB, in the present embodiment, the echo loss is 30dB, that is, 0.1% of reflected light will be generated at the End face, the reflected light is input from the output port, then split and output through a second input port with a splitting ratio of 1%, and then attenuated to 0.001%, that is-50 dB, and then enters a photoelectric receiver, which can monitor the power of the reflected light, and calculate the output power at the optical fiber End cap 24 according to the attenuation ratio, and the echo reflection of the optical fiber End cap 24 is detected, so that the output power monitoring accuracy is better. And 0.1% of reflected light is split and output to the optical fiber isolator 22 through the first input port with the splitting ratio of 99%, and then is blocked and isolated by the optical fiber isolator 22.
Second embodiment of fiber laser:
the fiber laser includes a laser generator including a seed light source (not shown) and a fiber amplifier 31, a 2 × 2 fiber coupler 33, a fiber isolator 32, a first fiber end cap 341, a second fiber end cap 342, and a photoelectric receiver 35, the laser source generated by the seed light source outputs laser of a preset power to the fiber isolator 32 after being amplified by the power of the fiber amplifier 31, and the fiber isolator 32 prevents return light from returning into the laser generator.
The splitting ratio of the 2 × 2 optical fiber coupler 33 is 50%, the 2 × 2 optical fiber coupler 33 is provided with a first input port, a second input port, a first output port and a second output port, the first input port and the second input port are located on the same side, the first output port and the second output port are located on the same side, the first input port and the first output port are located on opposite sides, the first input port is connected with the optical fiber isolator 32, the first optical fiber end cap 341 is connected with the first output port through an optical fiber, the second optical fiber end cap 342 is connected with the second output port through an optical fiber, the photoelectric receiver 35 is connected with the second input port, and the length of the optical fiber can be adjusted according to actual requirements.
After laser with preset power is input from the first input port, the laser is respectively output to the first optical fiber end cap 341 and the second optical fiber end cap 342 according to a splitting ratio of 50%, reflected light generated at the optical fiber end caps is input from corresponding output ports, the reflected light is split and output through the second input port with the splitting ratio of 50%, the reflected light is incident to a photoelectric receiver through attenuation of 50%, the photoelectric receiver can monitor the power of the reflected light, and the output power at the first optical fiber end cap 341 and/or the second optical fiber end cap 342 is calculated according to the attenuation ratio. Of course, it is also possible that the user can selectively arrange the fiber end caps at the first output port and the second output port according to actual requirements, so as to leave one of the output ports vacant or connect other devices.
Certainly, the above embodiments are only preferred embodiments of the present disclosure, and in specific applications, the present disclosure may have more variations, and a user may select different optical fiber end caps according to different laser output requirements, where different optical fiber end caps have different return loss, and select a suitable splitting ratio of the second input port according to the laser power of the optical fiber laser and the monitoring interval of the photoelectric receiver, for example, the splitting ratio of the second input port is between 0.1% and 1%, and the optical fiber isolator may also be integrated in the laser generator, that is, the output end of the laser generator is directly connected to the first input port.
Therefore, reflected light generated by the optical fiber end cap is output from the second input port according to a certain proportion of light splitting ratio and is input to the photoelectric receiver as optical power monitoring signal light, and then the output laser is monitored in real time by using simple optical path device arrangement.

Claims (9)

1. A fiber laser for simple monitoring of output power, comprising:
the laser generator is used for generating laser with preset power;
a 2 × 1 optical fiber coupler, the 2 × 1 optical fiber coupler being provided with a first input port, a second input port, and an output port, the first input port and the second input port being located on the same side, the first input port and the output port being located on opposite sides, the first input port being connected to the laser generator;
a fiber end cap connected with the output port;
a photoelectric receiver connected with the second input port.
2. The fiber laser of claim 1, wherein:
the splitting ratio of the second input port is between 0.1% and 1%.
3. The fiber laser of claim 1, wherein:
the return loss of the optical fiber end cap is between 30dB and 50 dB.
4. The fiber laser of claim 1, wherein:
the splitting ratio of the second input port is 1%, and the return loss of the optical fiber end cap is 30dB.
5. The fiber laser according to any of claims 1 to 4, characterized in that:
the fiber laser further comprises a fiber isolator connected between the first input port and the laser generator.
6. A fiber laser for simple monitoring of output power, comprising:
the laser generator is used for generating laser with preset power;
a 2 × 2 fiber coupler, wherein the splitting ratio of the 2 × 2 fiber coupler is 50%, the 2 × 2 fiber coupler is provided with a first input port, a second input port, a first output port and a second output port, the first input port and the second input port are located on the same side, the first output port and the second output port are located on the same side, the first input port and the first output port are located on opposite sides, and the first input port is connected with the laser generator;
a first optical fiber end cap connected with the first output port;
a photoelectric receiver connected with the second input port.
7. The fiber laser of claim 6, wherein:
the fiber laser also includes a second fiber end cap connected with the second output port.
8. The fiber laser of claim 6, wherein:
the first fiber end cap has a return loss between 45dB and 60 dB.
9. A fibre laser according to any of claims 6 to 8, wherein:
the fiber laser further comprises a fiber isolator, and the fiber isolator is connected between the first input port and the laser generator.
CN202211061568.5A 2022-08-31 2022-08-31 Fiber laser for simply monitoring output power Pending CN115395348A (en)

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Application Number Priority Date Filing Date Title
CN202211061568.5A CN115395348A (en) 2022-08-31 2022-08-31 Fiber laser for simply monitoring output power

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211061568.5A CN115395348A (en) 2022-08-31 2022-08-31 Fiber laser for simply monitoring output power

Publications (1)

Publication Number Publication Date
CN115395348A true CN115395348A (en) 2022-11-25

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CN202211061568.5A Pending CN115395348A (en) 2022-08-31 2022-08-31 Fiber laser for simply monitoring output power

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