A Praseodymium-Doped Fluorotellurite Glass Fiber and a 605-nm Band Laser Light Source Device Based on the Same

Abstract

The present invention discloses a praseodymium-doped fluorotellurite glass fiber and a 605-nm band laser light source device based on the same, belonging to the technical field of special glass fibers and devices. The praseodymium-doped fluorotellurite glass fiber has an all-solid structure. Among them, the core glass of the fiber is praseodymium-doped fluorotellurite glass (TBY-Pr), and the cladding of the fiber is a single-cladding or double-cladding structure, both of which are fluorotellurite glass. The praseodymium-ion doped fluorotellurite glass used in the 605-nm band laser light source device has a relatively high glass transition temperature and anti-deliquescence ability. Its full width at half maximum of the emission spectrum in the 605-nm band is 27 nm (619 - 592 nm), and the maximum emission cross-section is 3.92×10<supgt;‑21< / supgt; cm<supgt;2< / supgt>. The present invention uses this fiber as the gain medium and uses lasers with working wavelengths of 976 and 1400 nm as the pump sources to build an ASE light source and a laser with a central wavelength of 605 nm.

Description

Technical Field

[0001] The present invention belongs to the technical field of special glass fibers and devices, and particularly relates to a praseodymium-doped fluorotellurite glass fiber and a 605 nm band laser light source device based on the same. Background Art

[0002] The 605 nm band laser light source has wide application requirements in the fields of color display, biomedicine, material processing, microscopic imaging, and basic scientific research. The laser light source based on rare earth ion-doped fiber has the characteristics of low cost, small volume, good beam quality, etc., and is an effective means to realize the 605 nm band laser light source. At present, using praseodymium ion-doped fluoride glass fiber as the gain medium, the 605 nm band ASE and laser output have been realized. However, due to the low glass transition temperature (252 °C) and easy deliquescence of fluoride glass, during the long-term operation of the corresponding laser device, especially during high-power operation, the fiber end face is easily damaged, which limits the service life of the device and the further improvement of the output optical power. Summary of the Invention

[0003] Aiming at the above problems existing in the prior art, the present invention provides a praseodymium-doped fluorotellurite glass fiber and a 605 nm band laser light source device based on the same. The praseodymium ion-doped fluorotellurite glass adopted by the present invention has a high glass transition temperature and anti-deliquescence ability, and its full width at half maximum of the emission spectrum in the 605 nm band is 27 nm (619 - 592 nm), and the maximum emission cross-section is 3.92×10 -21 cm 2 ; The present invention uses this fiber as the gain medium, and uses lasers with working wavelengths of 976 and 1400 nm as the pump sources to build an ASE light source and a laser with a central wavelength of 605 nm.

[0004] The present invention is realized through the following technical solutions:

[0005] A praseodymium-doped fluorotellurite glass fiber is a fully solid structure. Among them, the core glass of the fiber is praseodymium-doped fluorotellurite glass (TBY-Pr), and includes the following components in mole percentage:

[0006]

[0007] The cladding of the fiber is a single-cladding or double-cladding structure, both of which are fluorotellurite glass, and includes the following components in mole percentage:

[0008]

[0009] Further, the core diameter of the praseodymium-doped fluorotellurite glass fiber is 0.5 - 10 μm, the thickness of the inner cladding of the praseodymium-doped fluorotellurite glass fiber is 5 - 62.5 μm, and the thickness of the outer cladding of the praseodymium-doped fluorotellurite glass fiber is 0 - 20 μm.

[0010] Further, the praseodymium-doped fluorotellurite glass fiber is prepared by a rod-tube method, an extrusion method or a double crucible method.

[0011] On the other hand, the present invention also provides a 605 nm band laser light source device based on a praseodymium-doped fluorotellurite glass fiber, which includes two pump sources, two isolators, a wavelength division multiplexer / pump combiner, a praseodymium ion-doped fluorotellurite glass fiber and a band-pass filter; the laser light emitted by the two pump sources sequentially passes through the isolators and is coupled in a wavelength division multiplexer or a pump combiner and then enters the same quartz fiber, and then is coupled into the praseodymium-doped fluorotellurite glass fiber by means of fusion splicing or butt joint. The end face of the praseodymium-doped fluorotellurite glass fiber is processed into an inclined surface to prevent backlight and suppress parasitic oscillation; as the pump light power is increased, a 605 nm band ASE light source can be realized.

[0012] Further, the two pump sources are respectively lasers with working wavelengths of 976 and 1400 nm.

[0013] Further, fiber gratings with appropriate reflectivity are inscribed at both ends of the praseodymium-doped fluorotellurite glass fiber to build a laser resonator; as the pump light power is increased, a 605 nm laser output can be realized.

[0014] Compared with the prior art, the advantages of the present invention are as follows:

[0015] A praseodymium-doped fluorotellurite glass fiber and a 605 nm band laser light source device based on the same of the present invention use a praseodymium-doped fluorotellurite glass fiber with a wide emission spectrum, a large stimulated emission cross section, a high glass transition temperature and good anti-deliquescence ability as a gain medium, and use a 976 and 1400 nm dual-wavelength laser pumping technology. Based on the stimulated emission transition process Pr 3+ : 1 D 2 → 3 H 4 , a broadband ASE light source with a central wavelength of 605 nm and a spectral full width at half maximum of 27 nm (619 - 592 nm) is realized; further, by building a resonator based on a fiber grating, a laser output with a working wavelength of 605 nm can be realized. Description of the Drawings

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts do not necessarily draw to actual scale.

[0017] Figure 1 Schematic diagram of a 605 nm band laser light source device based on praseodymium-doped fluorotellurite glass fiber;

[0018] In the figure: 976 nm laser 1, 1400 nm laser 2, 976 nm isolator 3, 1400 nm isolator 4, 976 / 1400 nm wavelength division multiplexer 5, praseodymium-doped fluorotellurite glass fiber 6, 380 - 670 nm band-pass filter 7, spectrum analyzer 8, fiber grating 9, optical power meter 10;

[0019] Figure 2 In Example 1 of the present invention, the molar percentages of each component prepared are: TeO 2 : 70%, BaF 2 : 20%, Y 2 O 3 : 9.975%, Pr 2 O 3 : Transmission spectrum of TBY-Pr glass with 0.025%;

[0020] Figure 3 Pr 3+ Energy level structure schematic diagram of ions;

[0021] Figure 4 In TBY-Pr glass 3 H 4 → 1 D 2 Absorption cross-section corresponding to the process and Pr 3+ Ions 1 D 2 → 3 H 4 Emission cross-section corresponding to the process;

[0022] Figure 5 Calculated gain cross-section of Pr 3+ Ions Process, corresponding to the gain cross-section from bottom to top with population inversion ratios of 0, 0.2, 0.4, 0.6, 0.8, and 1 respectively;

[0023] Figure 6ASE spectrum diagram in the 605nm band measured in a 6cm long praseodymium-doped fluorotellurite glass fiber when the 976 / 1400nm pump laser power is 578 / 657mW;

[0024] Figure 7 When the 1400nm laser pump power is fixed at 1W, the relationship between the laser output power in the 605nm band and the 976nm pump laser power measured in a 2m long praseodymium-doped fluorotellurite glass fiber. Detailed implementation manners

[0025] To clearly and completely describe the technical solution of the present invention and its specific working process, in combination with the accompanying drawings of the specification, the specific implementation manners of the present invention are as follows:

[0026] Example 1

[0027] This example provides a praseodymium-doped fluorotellurite glass fiber, which is a fully solid-state structure. Among them, the core glass of the fiber is praseodymium-doped fluorotellurite glass (TBY-Pr), including the following components in mole percentages:

[0028]

[0029]

[0030] The cladding of the fiber is a single-cladding or double-cladding structure, both of which are fluorotellurite glass, including the following components in mole percentages:

[0031]

[0032] The core diameter of the praseodymium-doped fluorotellurite glass fiber is 0.5 - 10μm, the thickness of the inner cladding of the praseodymium-doped fluorotellurite glass fiber is 5 - 62.5μm, and the thickness of the outer cladding of the praseodymium-doped fluorotellurite glass fiber is 0 - 20μm.

[0033] The praseodymium-doped fluorotellurite glass is prepared by the following method, which specifically includes the following steps:

[0034] According to the molar ratio TeO 2 : BaF 2 : Y 2 O 3 : Pr 2 O 3(TBY-Pr) = 70:20:9.975:0.025. Weigh 30 g of raw materials, put the weighed raw materials into an agate mortar and grind for 50 minutes to make the raw materials evenly mixed; put the mixed raw materials into a 50-ml crucible and place it in an electric furnace that has been heated to 950 °C for melting; after 30 minutes, pour the melted TBY-Pr glass liquid into a preheated mold. After the glass cools and forms, place it in an electric furnace that has been heated to 400 °C for heat treatment and annealing; after 3 h, turn off the power of the electric furnace; take it out after the furnace temperature cools to room temperature. The above process is completed in a glove box protected by a dry atmosphere. The prepared praseodymium-doped fluorotellurite glass is ground and polished to -2 mm, and its transmission spectrum is measured by a spectrophotometer UV3600 and a Fourier spectrometer Nicolet 6700 as Figure 2 shown. The absorption peaks at the central wavelengths of 445, 470, 483, 592, 1014, 1447, 1535, 1942, and 2250 nm in the figure respectively correspond to the ground state energy level 3 H 4 to the excited state energy level 3 P 2 、 1 I 6 、 3 P 0 、 1 D 2 、 1 G 4 、 3 F 4 、 3 F 3 、 3 F 2 and 3 H 6 transitions, as Figure 3 shown. Based on the transmission spectrum, the maximum stimulated emission cross-section of the Pr 3+ ion 1 D 2 → 3 H 4 transition process is 3.92×10 - 21 cm 2 , and the full width at half maximum of the spectrum is 30 nm (623 - 593 nm), as Figure 4 shown. When the population inversion ratio of the upper and lower energy levels > 0.2, optical amplification in the 605-nm band can be achieved, as Figure 5 shown. The above results indicate that the praseodymium-doped fluorotellurite glass fiber is promising for the development of a broadband 605-nm band ASE light source.

[0035] Perform a stability test on the above-prepared praseodymium-doped fluorotellurite glass:

[0036] The glass transition temperature of the praseodymium-doped fluorotellurate glass was tested by a differential thermal analyzer (Seiko TG-DTA 6200), which was 425°C and the crystallization starting temperature was 528°C. The difference between the two was 103°C, indicating that it can be used to develop high-quality praseodymium-doped fluorotellurate glass optical fibers.

[0037] The praseodymium-doped fluorotellurate glass prepared above was tested for its deliquescent performance:

[0038] A sample of the above-mentioned praseodymium-doped fluorotellurite glass was taken and weighed using an electronic balance to obtain a weight of 11.0489 g. The glass was then immersed in water, left for 7 days, taken out and dried. The weight of the sample was tested in the same manner, and no significant change was observed compared with the weight before the immersion treatment, and the weight loss ratio was 0.14‰. In addition, no significant change was observed in the light transmittance of the glass sample before and after the immersion treatment, indicating that the glass sample has good deliquescence resistance.

[0039] The praseodymium-doped fluorotellurate glass optical fiber is prepared by the following method, which specifically comprises the following steps:

[0040] According to the molar percentage TeO 2 :BaF 2 : Y 2 O 3 =68:22:10, accurately calculate and weigh 90g of raw materials; put the weighed raw materials into an agate mortar and grind for 60 minutes to fully mix the raw materials; put the mixed raw materials into a crucible and place it in an electric furnace that has been heated to 1000℃ for constant temperature melting for 90 minutes; inject the molten clarified glass liquid into the mold in the glass rotation casting system, and quickly cover the sealing cover; after 1 minute of high-speed rotation, put it into a 420℃ tubular electric furnace and keep it in a low-speed rotation (20 rpm) for annealing; after 5 hours, turn off the power of the electric furnace, wait until the furnace temperature drops to room temperature, take it out to get a TBY glass tube with an outer diameter of about 12mm and an inner diameter of about 3mm. The obtained TBY glass tube is ground and polished to remove surface defects and is ready for use.

[0041] First, the prepared praseodymium-doped fluorotellurate glass rod is fixed on a glass rod stretching system with a preform rod clamp and stretched to about 3 mm in outer diameter; then, it is placed in a TBY glass tube, fixed on an optical fiber drawing tower with a preform rod clamp and drawn into an optical fiber.

[0042] The loss of the praseodymium-doped fluorotellurate glass optical fiber prepared above was tested:

[0043] Transfer a praseodymium-doped fluorotellurite glass fiber with a core diameter of 10 μm and a length of 10 m to a fiber loss test system. The system consists of a pump source (continuous laser with a working wavelength of 1120 nm), a mechanical docking device, the fiber under test (praseodymium-doped fluorotellurite glass fiber), and a power detector. The pump light source is coupled into the core of the praseodymium-doped fluorotellurite glass fiber through the mechanical docking device. Fix the power of the pump laser, gradually shorten the length of the praseodymium-doped fluorotellurite glass fiber, and record the corresponding output power at different fiber lengths through the power detector. Plot the curve of the fiber output power versus the fiber length, and calculate its slope to obtain the transmission loss of the prepared praseodymium-doped fluorotellurite glass fiber at 1120 nm as 0.18 dB / m.

[0044] Example 2

[0045] This example provides a 605 nm band laser light source device based on a praseodymium-doped fluorotellurite glass fiber, including two pump sources, two isolators, a wavelength division multiplexer / pump combiner, a praseodymium-ion doped fluorotellurite glass fiber, and a band-pass filter; the laser light emitted by the two pump sources sequentially passes through the isolators and is coupled in a wavelength division multiplexer or a pump combiner and then enters the same quartz fiber, and then is coupled into the praseodymium-doped fluorotellurite glass fiber by means of fusion or docking. The end face of the praseodymium-doped fluorotellurite glass fiber is processed into an inclined plane to prevent backlight and suppress parasitic oscillation; as the pump light power increases, a 605 nm band ASE light source can be realized.

[0046] The 605 nm band laser light source device is prepared by the following method, which specifically includes the following steps:

[0047] The first step: Preparation of the praseodymium-doped fluorotellurite glass fiber, the specific steps are as follows:

[0048] (1), According to the molar ratio TeO 2 : BaF 2 : Y 2 O 3 : Pr 2 O 3 (TBY-Pr) = 70:20:9.975:0.025 and TeO 2 : BaF 2 : Y 2 O 3(TBY) = 68:22:10. Weigh 30 g of raw materials respectively. Put the weighed raw materials into an agate mortar and grind for 30 minutes to fully mix the raw materials. Put the well-mixed raw materials into a crucible and place it in an electric furnace preheated to 1000 °C for isothermal melting for 120 minutes. First, take out the molten TBY glass liquid and pour it into a preheated copper mold (cylinder). Then, take out the molten TBY-Pr glass liquid and pour it into the copper mold. Due to the thermal expansion and contraction effect, an inverted conical preform will be formed. After the glass cools and forms, place it in an electric furnace preheated to 420 °C for heat preservation annealing. After 200 minutes, turn off the power of the electric furnace. After the furnace temperature cools to room temperature, take it out. The entire melting process is carried out in a glove box filled with dry nitrogen. The outer diameter of the obtained composite fluorotellurite glass rod is about 10 mm. After the obtained composite fluorotellurite glass rod is ground and polished to remove surface defects, it is ready for use.

[0049] (2). According to the molar percentage TeO 2 : BaF 2 : Y 2 O 3 = 68:22:10, accurately calculate and weigh 90 g of raw materials. Put the weighed raw materials into an agate mortar and grind for 60 minutes to fully mix the raw materials. Put the well-mixed raw materials into a crucible and place it in an electric furnace preheated to 1000 °C for isothermal melting for 90 minutes. Pour the molten and clarified glass liquid into the mold in the glass rotary casting system and quickly cover the sealing cover. After 1 minute of high-speed rotation, put it into a tubular electric furnace at 420 °C and keep it for heat preservation annealing at a low speed of rotation (20 revolutions per minute). After 5 hours, turn off the power of the electric furnace. After the furnace temperature drops to room temperature, take it out to obtain a TBY glass tube with an outer diameter of about 12 mm and an inner diameter of about 3 mm. After the obtained TBY glass tube is ground and polished to remove surface defects, it is ready for use.

[0050] (3). First, fix the above-prepared praseodymium-doped fluorotellurite glass rod with a preform fixture in the glass rod stretching system and stretch its outer diameter to about 3 mm. Then, put it into the TBY glass tube, fix it on the optical fiber drawing tower with a preform fixture and draw it into an optical fiber.

[0051] The second step: Build a 605 nm band ASE light source device based on the praseodymium-doped fluorotellurite glass optical fiber;

[0052] Use a praseodymium-doped fluorotellurite glass optical fiber with a core diameter of 7 μm and a length of 6 cm as the gain medium to build as Figure 1The experimental setup of the 605 nm band ASE light source as shown in (a); The pump source 1 is a 976 nm laser with fiber-coupled output, and the pump source 2 is a Raman fiber laser with a working wavelength of 1400 nm. The lasers of the above two wavelengths respectively pass through their own isolators 3 and 4, and then are multiplexed into the same quartz fiber through a 976 / 1400 nm wavelength division multiplexer (WDM) 5, and then are coupled into the praseodymium-doped fluorotellurite glass fiber 6 in a mechanical butt joint manner. The output light of the praseodymium-doped fluorotellurite glass fiber passes through a band-pass filter 7 with a light transmission range of 380 - 670 nm, and finally is received and monitored by a spectral analyzer 8. When the 976 / 1400 nm pump laser powers are 578 / 657 mW, an ASE light output with a central wavelength of ~605 nm is obtained, as Figure 6 shown, and its full width at half maximum is 27 nm (619 - 592 nm).

[0053] Example 3

[0054] Using a praseodymium-doped fluorotellurite glass fiber with a core diameter of 3 μm and a length of 2 m as the gain medium to build the experimental setup of the 605 nm band fiber laser as shown in Figure 1 (b). The pump source 1 is a 976 nm laser with fiber-coupled output, and the pump source 2 is a Raman fiber laser with a working wavelength of 1400 nm. The lasers of the above two wavelengths respectively pass through their own isolators 3 and 4, and then are multiplexed into the same quartz fiber through a 976 / 1400 nm wavelength division multiplexer (WDM) 5, and then are coupled into the praseodymium-doped fluorotellurite glass fiber 6 in a mechanical butt joint manner. Fiber gratings (reflection wavelength 605 nm, the reflectivity of the input end grating is 96%, and the reflectivity of the input end grating is 60%) 9 inscribed at both ends of the praseodymium-doped fluorotellurite glass fiber are used to build a resonant cavity. The output light spectrum of the praseodymium-doped fluorotellurite glass fiber passes through a band-pass filter 7 with a light transmission range of 380 - 670 nm, and finally is received and monitored by a spectral analyzer 8, and the output power is monitored by a power meter 10. Fix the 1400 nm pump laser power at 1 W. When the 976 nm pump laser power increases to 0.57 W (threshold power), 605 nm laser output can be achieved. As the 976 nm pump laser power gradually increases to 2.5 W, the 605 nm laser output power correspondingly increases to 0.6 W, as Figure 7 shown, and the corresponding slope efficiency is 26.84%.

[0055] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0056] In addition, it should be noted that, for the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination manners.

[0057] In addition, any combinations can be made among the various different embodiments of the present invention, as long as they do not violate the idea of the present invention, and they should equally be regarded as the content disclosed by the present invention.

Claims

1. A 605nm band laser light source device based on praseodymium-doped fluorotellurate glass fiber, characterized in that: It includes two pump sources, two isolators, a wavelength division multiplexer / pump combiner, a praseodymium-doped fluorotellurate glass optical fiber and a bandpass filter; the lasers emitted by the two pump sources pass through the isolators in turn, are coupled in the wavelength division multiplexer or the pump combiner, and then enter the same quartz optical fiber, and then are coupled into the praseodymium-doped fluorotellurate glass optical fiber by fusion or docking. The end face of the praseodymium-doped fluorotellurate glass optical fiber is processed into a bevel to prevent light return and suppress parasitic oscillation; with the increase of pump light power, a 605nm band ASE light source can be achieved; The praseodymium-doped fluorotellurate glass optical fiber is a fully solid structure, wherein the core glass of the optical fiber is praseodymium-doped fluorotellurate glass, comprising the following components in molar percentage: The cladding of the optical fiber is a single cladding or double cladding structure, both of which are fluorotellurate glass, including the following molar percentage components: The core diameter of the praseodymium-doped fluorotellurate glass optical fiber is 0.5-10 μm, the thickness of the inner cladding of the praseodymium-doped fluorotellurate glass optical fiber is 5-62.5 μm, and the thickness of the outer cladding of the praseodymium-doped fluorotellurate glass optical fiber is 0-20 μm; The two pump sources are lasers with working wavelengths of 976 nm and 1400 nm respectively.

2. A 605 nm band laser light source device based on praseodymium-doped fluorotellurate glass optical fiber as claimed in claim 1, characterized in that: The praseodymium-doped fluorotellurate glass optical fiber is prepared by a rod-tube method, an extrusion method or a double-crucible method.

3. The 605 nm band laser light source device based on praseodymium-doped fluorotellurate glass optical fiber according to claim 1, characterized in that: Fiber Bragg gratings with appropriate reflectivity are engraved on both ends of the praseodymium-doped fluorotellurite glass optical fiber to build a laser resonant cavity; as the pump light power increases, 605nm laser output can be achieved.

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