CN219144703U

CN219144703U - Novel whispering gallery mode micro-laser with stable structure

Info

Publication number: CN219144703U
Application number: CN202222725979.1U
Authority: CN
Inventors: 饶娟娟; 杨凯
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2023-06-06
Anticipated expiration: 2032-10-17

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

Novel whispering gallery mode micro-laser with stable structure

Technical Field

The utility model relates to the field of fiber lasers, in particular to a novel whispering gallery mode micro-laser with stable structure, and especially relates to a preparation method for a fiber sensing device while being used for the whispering gallery mode micro-laser.

Background

Lasers have a very large number of applications in people's daily life as well as in work, such as laser surgery, laser machining, laser measurement, laser radar, etc. In many severe working environments, the temperature and humidity change conditions of surrounding spaces need to be monitored at all times so as to prevent dangers; the laser is also not separated from the processing of some precise small products. Lasers come in different forms in our lives, bringing convenience and safety to our lives.

As more and more people begin to focus on the laser area, a wide variety of fiber laser structures continue to emerge. Among them, stability of the structure and high quality factor have also led to pursuit of many researchers. At present, a micro laser based on a whispering gallery mode can realize the characteristic of high quality factor, but because some structures are that microspheres are placed in an open cavity, the positions of the microspheres slightly change, so that the performance of laser is degraded, and the laser is not easy to stably output. The utility model uses femtosecond laser to cut groove on the end face of single-mode fiber, and plugs the fluorescent microsphere into the groove, finally forms a stable microcavity structure by welding with a welding machine, which greatly improves the stability of the device.

Disclosure of Invention

Aiming at the defects of the prior art, the utility model provides a novel whispering gallery mode micro laser with stable structure and solves the problem of high optical fiber transmission loss. In the aspect of preparing materials, the single-mode fiber and the polyethylene fluorescent microsphere with low price are used, so that the research cost is reduced. Second, the device can also be used for temperature sensors based on the property of the microspheres that they are sensitive to temperature.

In order to achieve the above object, the present utility model is realized by the following technical scheme:

a novel whispering gallery mode micro-laser with stable structure comprises a semiconductor pumping source and a microcavity structure; the semiconductor pump source is a solid laser with the wavelength of 405nm; the microcavity structure comprises a single-mode fiber, a cube groove and fluorescent microspheres; the single-mode optical fiber is a common single-mode optical fiber and comprises a single-mode optical fiber 4 and a single-mode optical fiber 7; the cube groove is formed by femtosecond laser lithography at the position where the end face of the single-mode fiber 4 is positioned on the upper side of the fiber core and is close to the fiber core; the fluorescent microspheres are made of polyethylene, can be slowly conveyed into the cube groove by utilizing the stepping operation of a fusion splicer, are fixed by Ultraviolet (UV) glue, and are then fixed in the cube groove by irradiation of an ultraviolet lamp for 30 minutes.

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

The length, width and height of a cube groove carved by the femtosecond laser on the upper side of the fiber core of the single-mode fiber end face and close to the fiber core are respectively in the range of 35-45 mu m.

The diameter size of the fluorescent polyethylene microsphere is in the range of 27-32 mu m.

The fluorescent polyethylene microspheres have an emission wavelength of about 515nm.

Compared with the prior art, the utility model has the beneficial effects that:

1. the microcavity structure adopts a common single-mode fiber and a polyethylene fluorescent microsphere with low price, and has the advantages of simple manufacture, low cost and stable structure. The device can also be used for temperature sensors based on the property of fluorescent microspheres that they are sensitive to temperature.

2. The whispering gallery mode micro-laser is formed by utilizing femtosecond laser to score grooves and placing microspheres in the grooves and then carrying out discharge welding with another common single-mode fiber, and has the characteristics of simple operation, outstanding principle and easy combination with other applications. The whispering gallery mode has an ultrahigh quality factor (Q) value and a smaller mode volume, and the passband is narrower, so that the data has higher accuracy.

Drawings

In order to more clearly illustrate the embodiments or technical solutions of the present utility model, the present utility model is further described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an application system for implementing the present utility model.

FIG. 2 is a schematic diagram of a whispering gallery mode micro-laser according to the present utility model.

FIG. 3 is a schematic view of a etched polished single mode fiber after femtosecond grooving in accordance with the present utility model.

In the figure, a semiconductor pumping source, a microcavity structure, a spectrum analyzer, a single-mode optical fiber cladding, a single-mode optical fiber core, a square groove carved on one end of the single-mode optical fiber by femtosecond laser, a fluorescent microsphere, a single-mode optical fiber cladding and a single-mode optical fiber core are respectively arranged in the figure, wherein the semiconductor pumping source, the microcavity structure, the spectrum analyzer, the single-mode optical fiber cladding and the single-mode optical fiber core are respectively arranged in the figure, the fluorescent microsphere, the single-mode optical fiber and the single-mode optical fiber cladding are respectively arranged in the figure, and the single-mode optical fiber cladding and the single-mode optical fiber core are respectively arranged in the figure.

Detailed Description

The present utility model will be described in detail below with reference to the drawings and the specific embodiments, but is not limited thereto.

The implementation and application system of the utility model is shown in fig. 1, wherein 1 is a semiconductor pump source, 2 is a microcavity structure, and 3 is a spectrum analyzer. The connection mode 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 shows a schematic diagram of the whispering gallery mode micro laser according to the present utility model, which is composed of a single mode fiber 4, a micro groove 5, fluorescent microspheres 6, and a single mode fiber 7. Wherein the single-mode optical fiber 4 comprises a single-mode optical fiber cladding 4 (a), a single-mode optical fiber core 4 (b). Wherein the length, width and height of the micro groove 5 are larger than the diameter of the fluorescent microsphere 6, the single-mode fiber 7 comprises a single-mode fiber cladding 7 (a) and a single-mode fiber core 7 (b).

Fig. 3 is a schematic diagram of a corrosion polished single-mode fiber after femtosecond slotting, which consists of a single-mode fiber 4 and a micro-slot 5. Wherein the single-mode optical fiber 4 comprises a single-mode optical fiber cladding 4 (a), a single-mode optical fiber core 4 (b).

The manufacturing method and the steps of the echo wall mode micro laser are as follows: the first step: firstly, a square groove is carved on the upper side of the fiber core end face of a single-mode fiber by using femtosecond laser, during the grooving, the energy of the femtosecond laser is regulated to 500nJ, the power is regulated to 5mW, hydrofluoric acid (HF) is dripped on a micro groove after the grooving is finished, the micro groove is corroded for about 1 minute, and the micro groove is washed clean by clean water, so that a smoother micro groove channel 5 is obtained, as shown in figure 3; and a second step of: placing the carved micro-groove channel structure at one end of a fusion splicer, placing a conical tip optical fiber stained with fluorescent microspheres 6 at the other end of the fusion splicer, slowly conveying the fluorescent microspheres into the micro-groove by using the stepping operation of the fusion splicer, fixing the microspheres by using Ultraviolet (UV) glue, and then irradiating for 30 minutes by using an ultraviolet lamp to solidify the structure; and a third step of: taking down the tip of the conical optical fiber, placing the other single-mode optical fiber 7 at the other end of the fusion splicer, and carrying out discharge fusion splicing on the micro-groove structure loaded with the fluorescent microspheres and the other single-mode optical fiber 7 by the fusion splicer, so that a complete micro-laser structure can be formed after fusion splicing is finished, as shown in fig. 2; wherein the discharge amount of the welding machine is regulated to be in a 60bit mode, and the discharge time is 1300ms.

The specific working principle is described in connection with fig. 1 to 3: after the semiconductor pump source is connected into the microcavity structure, light propagating in the fiber core of the single-mode fiber 4 is coupled into the fluorescent microsphere through an evanescent field, the fluorescent microsphere not only plays a role of a resonator, but also enables electrons in a ground state to be transited to an excited state under the optical pumping of 405nm by a gain medium in the fluorescent microsphere, and at the moment, the electrons in the excited state are subjected to the action of external signal light to be transited to the ground state by stimulated radiation. Photons with the same characteristics as those of the incident signal photons are released in the process, and finally, the amplification of the optical signal emits laser light with the wavelength of about 515nm.

While the foregoing is directed to embodiments of the present utility model, other and further details of the utility model may be had by the present utility model, it should be understood that the foregoing description is merely illustrative of the present utility model and that no limitations are intended to the scope of the utility model, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the utility model.

Claims

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.