CN219144703U - A Novel Whispering Gallery Mode Microlaser with Stable Structure - Google Patents

Abstract

The utility model discloses a novel whispering gallery mode micro-laser with stable structure, and relates to the field of fiber lasers. The micro-cavity structure is a micro-laser structure based on an echo wall mode, which is formed by carving a square groove on the upper side of a fiber core, which is close to the fiber core, of the end face of a single-mode fiber 4 by using femtosecond laser, inserting fluorescent microspheres into the groove, fixing the fluorescent microspheres by using Ultraviolet (UV) glue, and welding the end face of the single-mode fiber 4 with the end face of another section of single-mode fiber 7 through a welding machine. Light propagating in the fiber core of the single-mode fiber 4 is coupled into the fluorescent microsphere through an evanescent field, and an echo wall mode light field established in the fluorescent microsphere interacts with a fluorescent gain medium to finally generate laser operation. The micro-laser based on the whispering gallery mode has the advantages of low cost, small transmission loss and stable structure, and can be used for sensing temperature and stress.

Description

A Novel Whispering Gallery Mode Microlaser with Stable Structure

technical field

The utility model patent relates to the field of fiber lasers, in particular to a novel whispering gallery mode micro-laser with stable structure, and especially to a preparation of a whispering gallery mode micro-laser that can be used as an optical fiber sensor.

Background technique

Laser has many applications in people's daily life and work, such as laser surgery, laser processing, laser measurement, laser radar, etc. In many severe working environments, it is necessary to monitor the temperature and humidity changes in the surrounding space at all times to prevent danger; and for the processing of some precision and small products, lasers are also inseparable. Lasers appear in all aspects of our lives in different forms, bringing convenience and safety to our lives.

As more and more people start to pay attention to the field of lasers, various fiber laser structures continue to emerge. Among them, the stability and high quality factor of the structure have also attracted the pursuit of many researchers. At present, micro lasers based on whispering gallery mode can achieve the characteristic of high quality factor, but because some structures place microspheres in open cavities, a slight change in the position of the balls will cause the performance of the laser to deteriorate, making it difficult to stabilize Laser output. However, the utility model patent proposes to use a femtosecond laser to carve grooves on the end face of a single-mode optical fiber, and insert fluorescent microspheres into the grooves. Finally, a relatively stable microcavity structure can be formed by welding with a welding machine, which greatly improves the reliability of the device. stability.

Utility model content

The utility model aims at the deficiencies of the prior art, provides a novel whispering gallery mode micro-laser with stable structure, and overcomes the problem of large optical fiber transmission loss. In terms of materials preparation, the use of low-cost single-mode optical fibers and polyethylene fluorescent microspheres reduces the cost of research. Second, based on the temperature-sensitive properties of the microspheres, the device can also be used as a temperature sensor.

In order to achieve the above object, the utility model is realized through the following technical solutions:

A novel whispering gallery mode micro-laser with stable structure, including a semiconductor pump source and a microcavity structure; the semiconductor pump source is a solid-state laser with a wavelength of 405nm; the microcavity structure includes a single-mode fiber, a cube groove, a fluorescent microspheres; the single-mode fiber is an ordinary single-mode fiber, including a single-mode fiber 4 and a single-mode fiber 7; the cuboid groove is engraved with a femtosecond laser on the end face of the single-mode fiber 4, which is located on the upper side of the core and is adjacent to the core The fluorescent microspheres are made of polyethylene, and the fluorescent microspheres can be slowly delivered to the cube groove by the stepping operation of the welding machine, and fixed with ultraviolet (UV) glue, and then irradiated with ultraviolet lamps for 30 minutes to use The fluorescent microspheres are fixed in the cube groove.

The core diameter and fiber diameter of the single-mode optical fiber are 9 μm and 125 μm, respectively.

The length, width and height of the square grooves carved by the femtosecond laser on the upper side of the core of the single-mode fiber end face and adjacent to the core are respectively in the range of 35 μm-45 μm.

The diameter of the fluorescent polyethylene microspheres is in the range of 27 μm-32 μm.

The emission wavelength of the fluorescent polyethylene microspheres is about 515nm.

The beneficial effects of the utility model compared with the prior art are:

1. The microcavity structure adopts low-cost ordinary single-mode optical fiber and polyethylene fluorescent microspheres, which have the advantages of simple fabrication, low cost and stable structure. Based on the characteristic that the fluorescent microspheres are sensitive to temperature, the device can also be used as a temperature sensor.

2. Using a femtosecond laser to carve grooves and place microspheres in the grooves, and then discharge and weld with another ordinary single-mode fiber to form a whispering gallery mode micro-laser, which is easy to operate, outstanding in principle, and easy to combine with other applications features. And because the whispering gallery mode has an ultra-high quality factor (Q) value, a small mode volume, and a narrow passband, the data often have high accuracy.

Description of drawings

In order to illustrate the embodiments or technical solutions of the utility model more clearly, the utility model will be further described below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of the implementation and application system of the utility model.

Fig. 2 is a structural schematic diagram of the whispering gallery mode micro-laser of the present invention.

Fig. 3 is a schematic diagram of the corroded and polished single-mode optical fiber after femtosecond slotting of the utility model.

In the figure, 1. Semiconductor pump source, 2. Microcavity structure, 3. Spectrum analyzer, 4. Single-mode fiber, 4(a). Single-mode fiber cladding, 4(b). Single-mode fiber core, 5. Cube groove carved by femtosecond laser at one end of single-mode fiber, 6. Fluorescent microspheres, 7. Single-mode fiber, 7(a). Single-mode fiber cladding, 7(b). Single-mode fiber core.

Detailed ways

The utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the utility model.

The implementation and application system of the utility model is shown in Figure 1, 1 is a semiconductor pump source, 2 is a microcavity structure, and 3 is a spectrum analyzer. The connection method is as follows: the semiconductor pump source 1 is connected with one end of the microcavity structure 2 , and the other end of the microcavity structure 2 is connected with the spectrum analyzer 3 .

FIG. 2 is a schematic structural diagram of the whispering gallery mode micro-laser of the present invention, which is composed of a single-mode optical fiber 4 , a microgroove 5 , fluorescent microspheres 6 and a single-mode optical fiber 7 . Wherein, the single-mode optical fiber 4 includes a single-mode optical fiber cladding 4(a), and a single-mode optical fiber core 4(b). The length, width and height of the microgroove 5 are larger than the diameter of the fluorescent microsphere 6, and the single-mode fiber 7 includes a single-mode fiber cladding 7(a) and a single-mode fiber core 7(b).

FIG. 3 is a schematic diagram of a corroded and polished single-mode optical fiber after femtosecond slotting of the utility model, which is composed of a single-mode optical fiber 4 and a microgroove 5 . Wherein, the single-mode optical fiber 4 includes a single-mode optical fiber cladding 4(a), and a single-mode optical fiber core 4(b).

The manufacturing method and steps of the whispering gallery mode micro-laser are: the first step: first use a femtosecond laser to engrave a cube groove next to the fiber core on the upper side of the end face of the single-mode optical fiber core, and during the groove, the femtosecond laser The energy is adjusted to 500nJ, the power is adjusted to 5mW, after the groove is completed, drop hydrofluoric acid (HF) on the microgroove, wait for about 1 minute to corrode, rinse with clean water, and a relatively smooth microgroove channel can be obtained5 , as shown in Figure 3; the second step: place the engraved microgroove channel structure on one end of the fusion splicer, place the tapered tip optical fiber coated with fluorescent microspheres 6 on the other end of the fusion splicer, and use the fusion splicer Step-by-step operation, the fluorescent microspheres can be slowly sent to the microgroove, and the balls are fixed with ultraviolet (UV) glue, and then irradiated with a UV lamp for 30 minutes to cure the structure; the third step: remove the tapered fiber tip, and place the Another single-mode optical fiber 7 is placed at the other end of the fusion splicer, and the micro-groove structure loaded with fluorescent microspheres is spliced with another single-mode optical fiber 7 by means of the fusion splicer. After the fusion is completed, a complete micro-laser can be formed. The structure is shown in Figure 2; the discharge capacity of the fusion splicer is adjusted to "60bit" mode, and the discharge time is 1300ms.

Combined with Figure 1 to Figure 3, the specific working principle is introduced: after the semiconductor pump source is connected to the microcavity structure, the light propagating in the single-mode fiber 4 core will be coupled into the fluorescent microsphere through the evanescent field, and the fluorescent microsphere The sphere not only acts as a resonator, but also the gain medium in the fluorescent microsphere will make the electrons in the ground state transition to the excited state under the optical pump of 405nm. At this time, the electrons in the excited state are affected by the external signal light, and undergo The excitation radiation transitions to the ground state. During this process, photons with the same characteristics as the incident signal photons are released, which eventually amplifies the optical signal and emits laser light at about 515nm.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above descriptions are only specific embodiments of the utility model and are not intended to limit the utility model. For the utility model, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model shall be included in the protection scope of the utility model.

Claims (5)

1. A novel whispering gallery mode micro-laser with stable structure is composed of a semiconductor pumping source, a microcavity structure and a spectrum analyzer, and is characterized in that: the semiconductor pumping source is connected with one end of the microcavity structure, and the other end of the microcavity structure is connected with the spectrum analyzer.

2. The structurally stable novel whispering gallery mode microlaser as claimed in claim 1 wherein: the microcavity structure comprises two sections of single-mode fibers, a cube groove and fluorescent microspheres.

3. The structurally stable novel whispering gallery mode microlaser as claimed in claim 2 wherein: the length, width and height of the cube groove are respectively in the range of 35-45 mu m.

4. The structurally stable novel whispering gallery mode microlaser as claimed in claim 2 wherein: the length of the two sections of single-mode fibers is 30cm, the diameter of the fiber core of the fiber is 9 mu m, and the diameter of the fiber cladding is 125 mu m.

5. The structurally stable novel whispering gallery mode microlaser as claimed in claim 2 wherein: the fluorescent microsphere is made of polyethylene with the diameter of 27-32 mu m.

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