An Er 3+ / Ce 3+ Co-doped silicate glass material, glass microspheres and lasers

Abstract

The application relates to an Er 3+ / Ce 3+ co-doped silicate glass material, a glass microsphere and a laser. The chemical formula of the Er 3+ / Ce 3+ co-doped silicate glass material is 4.8Al2O3-28.1Na2CO3-66.4SiO2-0.6Er2O3-0.1Ce2O3 in terms of molar percentage. In addition, the Er 3+ / Ce 3+ co-doped silicate glass microsphere is pumped by using a 980nm single-frequency laser and a 1480nm tunable laser, and the excitation of C-band laser can be realized. Compared with the prior art, the application dopes Ce 3+ to reduce the up-conversion of Er 3+ , thereby improving the fluorescence intensity of Er 3+ in the C-band. The prepared microsphere laser has the characteristics of high Q value, low threshold and small volume, and the obtained C-band laser can be widely applied to the fields of communication and sensing.

Description

Technical Field

[0001] This invention belongs to the field of microcavity laser technology, and particularly relates to an Er 3+ / Ce 3+ Co-doped silicate glass materials, glass microspheres, and lasers. Background Technology

[0002] Lasers are stimulated emission sources, unlike fluorescent sources generated by spontaneous atomic emission, and possess extremely high brightness, monochromaticity, and coherence. Due to their unique optical properties, lasers have been widely applied in modern agriculture, industry, medicine, communications, defense, and science and technology over the past few decades. With the advancement of micro-nano fabrication technology, optical microcavity resonators based on whispering-gallery modes have attracted considerable attention from scholars both domestically and internationally due to their small mode size and high quality factor, and are widely used in integrated optics, optical communications, and optical sensing.

[0003] After the discovery of optical whispering-gallery mode devices, researchers found that gain glass materials could be fabricated into microcavity laser devices with high quality factors. Whispering-gallery mode microcavity lasers utilize gain medium materials with low absorption and low scattering to confine light within the equatorial plane of a ring-shaped microcavity for an extended period through continuous total internal reflection. This effectively excites doped rare-earth ions, achieving low-threshold, narrow-linewidth laser output.

[0004] Erbium is a typical rare earth element. 3+ It exhibits near-infrared emission characteristics, and C-band emission can be obtained by pumping with 532nm, 660nm, 800nm, 980nm, and 1480nm, making it widely used in the communications field. However, Er 3+ The fluorescence emission intensity in the C-band is not high, resulting in low luminous efficiency and a high threshold for the laser. Summary of the Invention

[0005] The purpose of this invention is to improve Er 3+ The fluorescence intensity in the C-band provides an Er 3+ / Ce 3+ Co-doped silicate glass materials, glass microspheres, and lasers.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] This invention provides an Er 3+ / Ce 3+ The co-doped silicate glass material has the following chemical formula in molar percentage: 4.8Al2O3-28.1Na2CO3-66.4SiO2-0.6Er2O3-0.1Ce2O3.

[0008] The present invention also provides an Er 3+ / Ce 3+ A method for preparing co-doped silicate glass materials includes the following steps:

[0009] (1) Weigh each component according to the molar ratio of 4.8Al2O3-28.1Na2CO3-66.4SiO2-0.6Er2O3-0.1Ce2O3, stir and mix thoroughly, and heat until melted;

[0010] (2) Annealing the molten mixture yields Er. 3+ / Ce 3+ Co-doped silicate glass materials.

[0011] Further, in step (1), the stirring and mixing time is 100-150 min, preferably 110-130 min, and more preferably 120 min.

[0012] Furthermore, in step (1), the stirring and mixing is carried out in a ball mill.

[0013] Further, in step (1), the heating temperature is 1550-1600℃, preferably 1570℃.

[0014] Furthermore, in step (1), the heating is maintained for 110-130 minutes, preferably 120 minutes.

[0015] Furthermore, in step (2), after the material has been fully melted, it is poured into a preheated brass plate and annealed in a muffle furnace at 600°C for one hour.

[0016] The present invention also provides an Er 3+ / Ce 3+ Co-doped silicate glass microspheres, using the above-mentioned Er 3+ / Ce 3+ It is prepared by co-doping silicate glass materials.

[0017] Furthermore, the Er 3+ / Ce 3+ The diameter of the co-doped silicate glass microspheres is 80-140 μm, preferably 85-120 μm.

[0018] The present invention also provides an Er 3+ / Ce 3+ The preparation method of co-doped silicate glass microspheres includes the following steps:

[0019] S1: Weigh each component by molar ratio, mix thoroughly, heat until melted, and then stretch to obtain glass fiber;

[0020] S2: Taper the glass wire obtained in step S1 to obtain a semi-conical glass wire;

[0021] S3: Melt the semi-conical glass wire obtained in step S2 to obtain Er 3+ / Ce 3+ Co-doped silicate glass microspheres.

[0022] Furthermore, in step S1, the glass fibers are drawn using a gravity stretching method. Because there is significant surface tension at the container opening during the pouring of molten glass, a block of molten glass will accumulate at the opening. As the glass block falls, the stretched molten glass will rapidly cool and form glass fibers.

[0023] Furthermore, in step S1, the diameter of the glass wire is 85-110 μm, preferably 95-110 μm, and more preferably 100 μm.

[0024] Furthermore, in step S2, the glass wire is tapered using a flame tapering method. This method involves heating the glass wire in the middle with an oxyhydrogen flame using a tapering machine and stretching both ends until it breaks, thus preparing a semi-conical glass wire.

[0025] Furthermore, in step S2, the waist diameter of the semi-conical glass filament is 12-18 μm, preferably 15 μm.

[0026] Furthermore, in step S3, the melting is performed using an electric arc discharge method.

[0027] Furthermore, the intensity of the electric arc discharge is 100-120.

[0028] Furthermore, the duration of each arc discharge is 180-220 ms, preferably 200 ms.

[0029] Furthermore, the number of arc discharges is 1-3.

[0030] The present invention also provides an Er 3+ / Ce 3+ Co-doped silicate glass microsphere lasers, including Er 3+ / Ce 3+ Co-doped silicate glass microspheres, as well as fiber tapers, spectrometers, and pump sources.

[0031] Furthermore, the waist diameter of the fiber taper is 1-2 μm.

[0032] Furthermore, the fiber taper is formed by drawing single-mode optical fiber using a tapering machine.

[0033] Furthermore, the pump source includes one or more of a 980nm single-frequency laser or a 1480nm tunable laser.

[0034] Furthermore, for a 980nm single-frequency laser, Er is achieved by increasing its power until it exceeds a threshold. 3+ / Ce 3+ C-band laser excitation of co-doped silicate glass microspheres; for a 1480nm tunable laser, Er is achieved using a frequency sweeping method. 3+ / Ce 3+ C-band laser excitation of co-doped silicate glass microspheres.

[0035] The present invention also provides an Er 3+ / Ce 3+ The fabrication and modulation method of a co-doped silicate glass microsphere laser includes the following steps:

[0036] a. Drawing single-mode optical fiber into an optical fiber taper;

[0037] b. Connect the two ends of the fiber taper obtained in step a to the pump source and the spectrometer, respectively;

[0038] c. Er 3+ / Ce 3+ The equatorial surface of the co-doped silicate glass microspheres was adjusted to be in a critical coupling state with the fiber taper;

[0039] d. Adjusting the pump light source to achieve Er 3+ / Ce 3+ Laser excitation of co-doped silicate glass microspheres.

[0040] Furthermore, in step d, when the pump source is a 1480nm tunable laser, its frequency sweeping method includes the following steps:

[0041] ① Turn on the tunable laser and tune its wavelength to Er 3+ The excitation wavelength was set to 1490 nm, and the power was increased, but microsphere lasers were not successfully excited.

[0042] ② Adjust the tunable laser to perform wavelength sweeping, with a range of 1480-1490nm and a sweeping speed of 2nm / s;

[0043] ③ Turn off the frequency sweep and continue pumping with a 1490nm single-frequency laser to achieve C-band laser.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) This invention uses Er 3+ / Ce 3+ Co-doping technology, through Er3+ Ce doping in silicate glass 3+ To reduce Er 3+ upconversion thus improves Er 3+ The fluorescence intensity in the C-band further increased Er 3+ Luminescence efficiency of silicate glass microspheres.

[0046] (2) In the glass microsphere laser of the present invention, Er can be excited by two laser excitation methods. 3+ Silicate glass microspheres were pumped. When pumping the microspheres with a 1480nm tunable laser, Er was increased by employing a frequency sweeping method. 3+ / Ce 3+ The absorption power of co-doped silicate glass microspheres is specifically due to Er 3+ / Ce 3+ During the frequency sweep process, co-doped silicate glass microspheres accumulate heat, causing Er 3+ / Ce 3+ The resonant wavelength of the co-doped silicate glass microspheres red-shifts. After the frequency sweep is turned off, heat is dissipated, the resonant wavelength blue-shifts back to the pump wavelength and is locked, increasing the pump absorption power and thus achieving C-band laser excitation.

[0047] (3) Er prepared by the present invention 3+ / Ce 3+ Co-doped silicate glass microsphere lasers have the characteristics of high Q value, low threshold and small size, and the obtained C-band lasers can be widely used in communication, sensing and other fields. Attached Figure Description

[0048] Figure 1 Er prepared in Example 1 3+ / Ce 3+ Absorption spectrum of co-doped silicate glass in the 600-1600 nm wavelength range.

[0049] Figure 2 Er prepared in Example 1 3+ / Ce 3+ Co-doped silicate glass and Er prepared in Comparative Example 1 3+ Fluorescence spectrum of doped glass in the 1400-1600nm band under 980nm pump.

[0050] Figure 3 Er prepared in Example 1 3+ / Ce 3+ Co-doped silicate glass and Er prepared in Comparative Example 1 3+ Fluorescence spectrum of the doped glass in the 648-680 nm range under 980 nm pump.

[0051] Figure 4Er prepared in Example 1 3+ / Ce 3+ Laser experimental optical path diagram of co-doped silicate glass.

[0052] Figure 5 Er prepared in Example 1 3+ / Ce 3+ The single-mode lasing characteristics of co-doped silicate glass microspheres pumped by a 980nm laser, the inner figure shows Er 3+ / Ce 3+ A photograph of co-doped silicate glass microspheres.

[0053] Figure 6 Er prepared in Example 1 3+ / Ce 3+ Multimode lasing characteristics of co-doped silicate glass microspheres pumped by a 1480nm tunable laser.

[0054] Figure 7 Er prepared in Example 1 3+ / Ce 3+ Laser threshold curves of co-doped silicate glass microspheres under a 980nm laser.

[0055] Figure 8 Er prepared in Example 1 3+ / Ce 3+ The wavelength shift diagram of whispering-gallery mode resonant wavelengths of co-doped silicate glass microspheres pumped by a 1480nm tunable laser 2 and a broadband light source 3.

[0056] Explanation of markings in the diagram:

[0057] 1-980nm single-frequency laser, 2-1480nm tunable laser, 3-broadband light source, 4-optical switch, 5-three-dimensional displacement stage, 6-Er 3+ / Ce 3+ 7-Microscope, 8-Computer, 9-Isolator, 10-Spectrometer. Detailed Implementation

[0058] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0059] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available and have a purity ≥99.9%.

[0060] Example 1:

[0061] This embodiment provides an Er 3+ / Ce 3+ Co-doped silicate glass materials and Er 3+ / Ce 3+ The co-doped silicate glass microspheres 6 and their preparation method are as follows:

[0062] (1) The mass of each raw material was calculated based on a total mass of 15g and a molar ratio of 4.8Al2O3-28.1Na2CO3-66.4SiO2-0.6Er2O3-0.1Ce2O3. The raw materials were weighed using an electronic balance and then mixed. The mixture was then stirred using a ball mill (YXQM-2L) for 120min.

[0063] (2) Place the stirred mixture into a 50mL alumina crucible with a lid and place it in a high-temperature lifting furnace. Heat it at 1570℃ for 60 minutes.

[0064] (3) After the material has fully melted, pour it into a preheated brass plate, then anneal it in a muffle furnace at 600°C for one hour, and then grind and polish it to obtain Er. 3+ / Ce 3+ The silicate glass material is co-doped; at the same time, during the pouring of the brass plate, a glass filament with a diameter of about 100 μm is drawn by gravity stretching.

[0065] (4) The glass filament was tapered using the flame taper method (the taper machine used was the fiber taper machine of Shanghai Oubo Optoelectronics Co., Ltd.) to obtain a semi-conical glass filament with a waist diameter of about 15 μm, which was used for the subsequent preparation of microspheres.

[0066] (5) An improved arc discharge method was used to melt a semi-conical glass wire to prepare Er 3+ / Ce 3+ 6. Co-doped silicate glass microspheres. The main parameters of the improved arc discharge method (using a fiber optic fusion splicer, Furukawa 179C) are as follows: single arc discharge intensity of 110, arc discharge duration of 200 ms, and number of discharges of 3. 3+ / Ce 3+ The shape of the co-doped silicate glass microspheres 6 is as follows Figure 5 As shown in the inner diagram, the diameter is 90.17 μm.

[0067] Comparative Example 1:

[0068] This comparative example provides an Er 3+ The preparation method of doped silicate glass is as follows:

[0069] (1) Calculate the mass of each raw material based on a total mass of 15g and a molar ratio of 4.8Al2O3-28.2Na2CO3-66.4SiO2-0.6Er2O3. Weigh the raw materials using an electronic balance and mix them. Then, stir the mixture using a ball mill (YXQM-2L) for 120min.

[0070] (2) Place the stirred mixture into a 5mL alumina crucible with a lid and place it in a high-temperature lifting furnace. Heat it at 1570℃ for 60 minutes.

[0071] (3) After the material has fully melted, pour it into a preheated brass plate, then anneal it in a muffle furnace at 600°C for one hour, and then grind and polish it to obtain Er. 3+ Doped silicate glass.

[0072] The absorption spectrum of the silicate glass prepared in step (3) in Example 1 in the 600-1600 nm range is shown below. Figure 1 As shown, Er 3+ The absorption wavelengths and energy levels corresponding to the absorption peaks have been marked.

[0073] The fluorescence spectra of the silicate glasses prepared in step (3) of Example 1 and Comparative Example 1 in the C-band are shown below. Figure 2 As shown: relative to Er 3+ Doped glass, under 980nm pump, Er 3+ / Ce 3+ The fluorescence intensity in the C-band of co-doped silicate glass is significantly improved.

[0074] The fluorescence spectra of the silicate glasses prepared in step (3) of Example 1 and Comparative Example 1 in the 661 nm band are shown below. Figure 3 As shown: relative to Er 3+ Doped glass, under 980nm pump, Er 3+ / Ce 3+ The fluorescence intensity of co-doped silicate glass decreases at 661 nm.

[0075] Figure 2 and Figure 3 This fully illustrates the doped Ce 3+ By reducing Er 3+ The upconversion thus improves Er 3+ The downconversion of .

[0076] Example 2:

[0077] This embodiment provides an Er 3+ / Ce 3+ The fabrication and modulation method of co-doped silicate glass microsphere lasers includes the following steps:

[0078] (1) The single-mode optical fiber is drawn into an optical fiber taper of about 2μm using a tapering machine.

[0079] (2) Building such Figure 4 The experimental optical path shown is for Er in Example 1. 3+ / Ce 3+ Excitation was performed using co-doped silicate glass microspheres 6.

[0080] (3) One end of the fiber optic taper is connected to a pump source, namely a 980nm single-frequency laser 1 and a 1480nm tunable laser 2, and the pump source is selected by using an optical switch 4. The other end of the fiber optic taper is optically connected to a spectrometer 10 equipped with an isolator 9 to obtain Er. 3+ / Ce 3+ C-band laser for co-doped silicate glass microspheres 6.

[0081] (4) Adjust Er using a high-precision three-dimensional displacement platform 5 3+ / Ce 3+ Co-doped silicate glass microspheres 6. Er was observed simultaneously via a computer 8 connected to a microscope 7. 3+ / Ce 3+ The displacement of the co-doped silicate glass microsphere 6 causes its equatorial plane to be in a critical coupling state with the fiber taper.

[0082] (5) Turn on the pump light source.

[0083] a. For a 980nm laser pumped by one pump, increase the laser power until it exceeds the threshold of the microsphere laser to achieve C-band laser excitation. (See attached...) Figure 5 As shown, a 980nm laser with a power of 4mW successfully excited a narrow-linewidth laser at 1536.1nm, with a linewidth of 0.02nm and a power of -27.1dBm.

[0084] b. For the 1480nm tunable laser 2, a frequency sweep method was used to achieve C-band laser emission. First, the wavelength was tuned to the excitation wavelength of 1490nm, and the power was increased to 10mW, but the microsphere laser was not successfully excited at this time. Then, the 1480nm tunable laser 2 was adjusted to perform a frequency sweep in the range of 1480-1490nm at a sweep speed of 2nm / s. At this time, laser excitation could be observed on the spectrometer 10. The frequency sweep was turned off, and pumping with the 1490nm laser continued, successfully and stably exciting Er. 3+ / Ce 3+ Lasers co-doped silicate glass microspheres 6, such as Figure 6 As shown, multimode lasers near the C-band were successfully excited. Figure 7 The figure shows the laser threshold curve under 980nm pump, with a threshold of 0.782mW.

[0085] Figure 8 A 1480nm tunable laser 2 and a broadband light source 3 were used to measure Er. 3+ / Ce 3+ The resonant wavelength change of co-doped silicate glass microspheres 6 due to frequency sweeping. First, the broadband light source 3 is turned on, and the wavelength of the 1480nm tunable laser 2 is adjusted to 1550nm. Er 3+ / Ce 3+ The co-doped silicate glass microspheres 6 are in an anresonant state at this pump wavelength, exhibiting low absorption power, but are in a resonant state at 1544.596 nm. When the frequency sweep is initiated, the microspheres gradually accumulate heat, causing a redshift in the resonant wavelength. When the frequency sweep is deactivated, Er... 3+ / Ce 3+ The co-doped silicate glass microspheres 6 consume heat and cause a blue shift in the resonant wavelength. However, during this blue shift, the wavelength of the 1480nm tunable laser 2 locks into the resonant wavelength, preventing the whispering-gallery mode from reverting to the pre-sweep mode. Therefore, the blue shift in the resonant wavelength of the post-sweep whispering-gallery mode compared to the pre-sweep mode improves Er. 3+ / Ce 3+ Absorption power of co-doped silicate glass microspheres 6 at a pump wavelength of 1550nm from a 1480nm tunable laser 2.

[0086] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An Er 3+ / Ce 3+ co-doped silicate glass microsphere laser, characterized in that, including Er 3+ / Ce 3+ Co-doped silicate glass microspheres, optical fiber tapers, optical spectrometer and pump light source, the pump light source comprising a 980 nm single-frequency laser and a 1480 nm tunable laser; The Er 3+ / Ce 3+ The chemical formula of the composition of the co-doped silicate glass microspheres is 4.8 Al2O3-28.1 Na2CO3-66.4 SiO2-0.6 Er2O3-0.1 Ce2O3 in terms of molar percentage composition. The Er 3+ / Ce 3+ A method of making and tuning a co-doped silicate glass microsphere laser includes the steps of: a. drawing a single-mode optical fiber into an optical fiber taper; b. Connecting the two ends of the fiber taper obtained in step a with a pump light source and a spectrometer respectively; one end of the fiber taper is connected with a pump light source, which is a 980 nm single-frequency laser and a 1480 nm tunable laser respectively, and a light switch is used to select the pump source; the other end of the fiber taper is connected with a spectrometer with an isolator in the optical path, so as to obtain the Er 3+ / Ce 3+ C-band laser of co-doped silicate glass microsphere; c. Er 3+ / Ce 3+ The equatorial plane of the co-doped silicate glass microsphere is adjusted to be in a critical coupling state with the fiber taper; d. Adjusting the pump light source to realize 980nm and 1480nm dual light source for Er 3+ / Ce 3+ Laser excitation of co-doped silicate glass microsphere; for 1480nm tunable laser, sweep mode is used to realize Er 3+ / Ce 3+ C-band laser excitation of co-doped silicate glass microsphere to significantly enhance the absorption efficiency of pump light.

2. A laser according to claim 1 wherein the Er 3+ / Ce 3+ co-doped silicate glass microsphere laser, characterized in that, The Er 3+ / Ce 3+ The co-doped silicate glass microspheres have a diameter of 80-140 μm.

3. A laser as claimed in claim 1 wherein the Er 3+ / Ce 3+ co-doped silicate glass microsphere laser, characterized in that, The Er 3+ / Ce 3+ A method of making co-doped silicate glass microspheres includes the steps of: S1: weighing each component according to a molar ratio, mixing by stirring, melting by heating, and then preparing glass filaments by drawing; S2: performing tapering treatment on the glass filaments prepared in step S1 to obtain semi-tapered glass filaments; S3: melting the semi-conical glass filaments prepared in step S2 to obtain Er 3+ / Ce 3+ co-doped silicate glass microspheres.

4. An Er 3+ / Ce 3+ co-doped silicate glass microsphere laser, characterized in that, In step S1, the diameter of the glass filaments is 85-110 μm.

5. An Er 3+ / Ce 3+ Co-doped silicate glass microsphere laser, characterized in that, In step S2, the waist diameter of the semi-tapered glass filaments is 12-18 μm.

6. An Er 3+ / Ce 3+ Co-doped silicate glass microsphere laser, characterized in that, In step S3, the melting is performed by arc discharge method, the arc discharge intensity is 100-120, the duration of each arc discharge is 180-220 ms, and the number of arc discharges is 1-3.

7. An Er 3+ / Ce 3+ Co-doped silicate glass microsphere laser, characterized in that, The waist diameter of the optical fiber taper is 1-2 μm.

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