A bismuth-doped aluminum silicate optical fiber amplifier

Abstract

The present invention discloses a bismuth-doped aluminum silicate fiber amplifier, which belongs to the field of optical fiber communication technology. The bismuth-doped aluminum silicate fiber amplifier includes a pump laser, a wavelength division multiplexer, and a bismuth-doped aluminum silicate fiber. The two ends of the bismuth-doped aluminum silicate fiber are respectively connected to the wavelength division multiplexer and a digital power meter through SMF780 fiber. The digital power meter monitors the transmitted pump power, and a spectrum analyzer is used to reversely record the amplified signal light; the bismuth-doped aluminum silicate fiber is located in a refrigeration environment. The present invention adopts the above-mentioned bismuth-doped aluminum silicate fiber amplifier, and by performing low-temperature treatment on the bismuth-doped aluminum silicate fiber, a significant luminescence enhancement is obtained in the range of 1100nm-1350nm pumped at 830nm, and the quantum efficiency is increased by 1.3 times.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber communication, and in particular relates to a bismuth-doped aluminum silicate optical fiber amplifier. Background Art

[0002] Element-doped optical fibers have great application prospects in amplifying small signal light, among which bismuth-doped optical fibers are considered to be a very promising ultra-wideband near-infrared fluorescent material. The ultra-wideband luminescence of bismuth benefits from the formation of various bismuth active centers (BACs) coordinated with silicon (BAC-Si), phosphorus, aluminum (BAC-Al), germanium (BAC-Ge), etc. Among these BACs, the luminescence characteristics and energy levels of BAC-Si and BAC-Ge have been determined, and the central luminescence wavelengths are 1430 and 1650nm, respectively. The central luminescence wavelength of BAC-Al is closely related to the pump wavelength and covers a relatively wide wavelength range of 1.1μm-1.3μm, so the study of the spectral properties of BAC-Al is challenging. The laser efficiency ((η~25%)) of bismuth-doped optical fibers based on Al2O3-SiO2 is the lowest among bismuth-doped lasers, so the study of the spectral properties of bismuth-doped aluminum silicate fibers (BDFs) is of great significance to improve their applications in superluminescent light sources, optical fiber communications, sensing and astrophysics.

[0003] Temperature plays an important role in the formation of BACs. Under appropriate thermal annealing processes, the concentration of BACs can be increased, resulting in an increase in the luminescence intensity and gain coefficient in the range of 1400nm-1650nm (BAC-Si and BAC-Ge). However, there are relatively few studies on the spectral properties of BACs under low temperature conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a bismuth-doped aluminum silicate fiber amplifier, which obtains obvious luminescence enhancement in the range of 1100nm-1350nm pumped at 830nm by low-temperature treatment of the bismuth-doped aluminum silicate fiber, and provides a new idea for the application of bismuth-doped aluminum silicate fiber.

[0005] To achieve the above-mentioned purpose, the present invention provides a bismuth-doped aluminum silicate fiber amplifier, comprising a pump laser, a wavelength division multiplexer, and a bismuth-doped aluminum silicate fiber. The two ends of the bismuth-doped aluminum silicate fiber are respectively connected to the wavelength division multiplexer and a digital power meter through SMF780 fibers. The digital power meter monitors the transmitted pump power, and a spectrum analyzer is used to reversely record the amplified signal light. The bismuth-doped aluminum silicate fiber is located in a refrigeration environment.

[0006] Preferably, the refrigeration environment is a 77K liquid nitrogen environment, and the bismuth-doped aluminum silicate optical fiber is completely immersed in a 1L liquid nitrogen Dewar flask to maintain the low temperature environment of the bismuth-doped aluminum silicate optical fiber.

[0007] Preferably, the bismuth-doped aluminum silicate optical fiber comprises the following components in mass percentage: 34.46% Si, 19.09% Ge, 46.25% O, 0.15% Bi and 0.05% Al.

[0008] Preferably, the length of the bismuth-doped aluminum silicate optical fiber is 1-5 cm.

[0009] Preferably, the wavelength of the pump laser is 830 nm.

[0010] The preparation method of bismuth-doped aluminum silicate optical fiber is as follows: bismuth and aluminum oxide are deposited together with Bi(thd)3 and Al(CH3)3 precursors in a pure silica tube (Heraeus 300) by atomic ALD method, and the doped silica preform is pulled into an optical fiber with a core diameter of 4.6μm and a cladding diameter of 124μm to obtain bismuth-doped aluminum silicate optical fiber.

[0011] The bismuth-doped aluminum silicate fiber amplifier described in the present invention performs low-temperature treatment on BDF in a liquid nitrogen environment, so that the optical transition of BAC-Al(II) at 1300nm is promoted under the pumping condition of 830nm, higher luminous efficiency and larger bandwidth are generated in the near-infrared spectrum range, and the quantum efficiency is improved by 1.3 times.

[0012] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of an embodiment of a bismuth-doped aluminum silicate optical fiber amplifier of the present invention;

[0014] Figure 2 The small signal absorption spectrum of BDF in the visible light and near infrared region in an embodiment of a bismuth-doped aluminum silicate optical fiber amplifier of the present invention;

[0015] Figure 3 The luminescence spectra of BDF in the embodiments and comparative examples under 405nm and 532nm wavelength laser pumping;

[0016] Figure 4 Graph showing the relationship between the luminous intensity of BDF and the pump input power under 532nm wavelength laser pumping in the embodiment and the comparative example;

[0017] Figure 5 The luminescence spectrum of BDF in the embodiment and the comparative example under 980nm wavelength laser pumping;

[0018] Figure 6The luminescence spectrum of BDF in the embodiment and comparative example under 830nm wavelength laser pumping;

[0019] Figure 7 Spectral Gaussian decomposition of BAC under 830nm wavelength laser pumping in the embodiments and comparative examples. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0021] Example

[0022] like Figure 1 As shown, a bismuth-doped aluminum silicate fiber amplifier includes a pump laser, a wavelength division multiplexer, and a bismuth-doped aluminum silicate fiber. The two ends of the bismuth-doped aluminum silicate fiber are respectively connected to the wavelength division multiplexer and a digital power meter through SMF780 fibers. The digital power meter monitors the transmitted pump power, and a spectrum analyzer is used to reversely record the amplified signal light. The bismuth-doped aluminum silicate fiber is located in a refrigeration environment.

[0023] The refrigeration environment is a liquid nitrogen environment at 77 K. The bismuth-doped aluminum silicate optical fiber is completely immersed in a 1L liquid nitrogen Dewar flask to maintain the low temperature environment of the bismuth-doped aluminum silicate optical fiber.

[0024] The bismuth-doped aluminosilicate optical fiber includes the following components in mass percentage: 34.46% Si, 19.09% Ge, 46.25% O, 0.15% Bi and 0.05% Al.

[0025] The length of the bismuth-doped aluminosilicate optical fiber is 2 cm.

[0026] The preparation method of bismuth-doped aluminum silicate optical fiber is as follows: bismuth and aluminum oxide are deposited together with Bi(thd)3 and Al(CH3)3 precursors in a pure silica tube (Heraeus 300) by atomic ALD method, and the doped silica preform is pulled into an optical fiber with a core diameter of 4.6μm and a cladding diameter of 124μm to obtain bismuth-doped aluminum silicate optical fiber.

[0027] Comparative Example

[0028] The difference between this comparative example and the embodiment is that the bismuth-doped aluminum silicate optical fiber is placed in a room temperature environment of 300K.

[0029] The small signal absorption spectrum of the BDF prepared in the embodiment was measured by a monochromator lock-in amplifier system using a conventional back-switching method. The small signal absorption spectrum of BDF in the visible and near-infrared regions is shown in FIG. Figure 2As shown, there are two groups of absorption bands related to BAC, namely, the BAC-Al absorption bands at 500nm, 700nm and 1000nm, and the BAC-Si absorption bands at 816nm and 1400nm.

[0030] The luminescence spectra of BDF in the embodiments and comparative examples under visible wavelength laser pumping of 405nm and 532nm were studied. The results are as follows: Figure 3 As shown. The results show that under both pump wavelengths, there is a main luminescence band of BAC-Al centered at 1100nm. Under 405nm pumping, the luminescence bands of BAC-Ge (950nm) and BAC-Si (1430nm) are excited. Under 532nm pumping, there is only one main luminescence peak of BAC-Al. Under the cooling effect of liquid nitrogen temperature, the half-maximum width (FWHM) of the main peak of BAC-Al was observed to narrow by 20nm at both pump wavelengths. The narrowing of the bandwidth is mainly due to the suppression and weakening effect of uniform broadening at relatively low temperatures.

[0031] The relationship between the luminous intensity and the pump input power under 532nm visible wavelength laser pumping was studied. Figure 4 The results show that the comprehensive luminescence intensity of BAC-Al increases steadily with the increase of pump power at room temperature and in liquid nitrogen environment, and approaches saturation when the pump power exceeds 5mW. The quantum efficiency does not really change with temperature, which indicates that BDF has stable and good spectral performance in practical spectral applications related to temperature.

[0032] The luminescence spectra of BDF at room temperature and liquid nitrogen environment under 980nm pumping conditions were studied. Figure 5 The results are similar to those at short pump wavelengths, in that low temperature does not have much effect on the spectral shape of BAC-Al, except that the bandwidth is reduced from 126 nm to 106 nm.

[0033] The luminescence spectra of BDF at room temperature and liquid nitrogen environment under 830nm pumping conditions were studied. Figure 6 As shown. The results show that under 830nm pumping conditions, the shape of the luminescence spectrum changes significantly, and the luminescence band in the range of 1000-1350nm increases and widens significantly. The shape of the luminescence band of BAC-Si remains unchanged at room temperature and liquid nitrogen conditions, except that the half-peak width decreases from 105nm to 82nm. At room temperature and liquid nitrogen conditions, the luminescence intensity of BAC increases with increasing pump power and does not show saturation at the maximum pump power of 100mW. Pumping at 830nm achieves multiple optical transitions of BAC, which contributes to broadband spectral luminescence.

[0034] In order to more clearly illustrate the spectral changes, the luminescence spectrum was analyzed by Gaussian decomposition. The decomposition results are as follows: Figure 7 As shown. The results show that in addition to the BAC-Al(I) luminescence band around 1100nm and BAC-Si around 1430nm; there is another luminescence band around 1300nm, which is labeled as BAC-Al(II). By subjecting BDF to liquid nitrogen cooling, the BAC-Al(II) emission at 1300nm is significantly enhanced, bridging the luminescence between BAC-Al(I) and BAC-Si, which is beneficial to improving the bandwidth and luminescence intensity of BDF. The quantum efficiency of BDF increased by 1.3 times under 830nm pumping. Pumping around 830nm at low temperature promotes the optical transition of BAC-Al(II) at 1300nm, resulting in higher luminescence efficiency and larger bandwidth in the near-infrared spectral range.

[0035] After taking BDF out of the liquid nitrogen environment and placing it at room temperature for testing, the luminescence spectrum of BAC returned to its original room temperature state. Low-temperature treatment can achieve reversible enhancement of BDF luminescence.

[0036] Therefore, the present invention adopts the above-mentioned bismuth-doped aluminum silicate fiber amplifier, and obtains obvious luminescence enhancement in the range of 1100nm-1350nm pumped at 830nm by low-temperature treatment of the bismuth-doped aluminum silicate fiber, and the quantum efficiency is improved by 1.3 times.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A bismuth-doped aluminum silicate optical fiber amplifier, characterized in that: It includes a pump laser, a wavelength division multiplexer, and a bismuth-doped aluminum silicate optical fiber. The two ends of the bismuth-doped aluminum silicate optical fiber are respectively connected to the wavelength division multiplexer and a digital power meter through SMF780 fibers. The digital power meter monitors the transmitted pump power, and uses a spectrum analyzer to reversely record the amplified signal light. The bismuth-doped aluminum silicate optical fiber is located in a refrigeration environment. The refrigeration environment is a 77K liquid nitrogen environment; The bismuth-doped aluminum silicate optical fiber includes the following components in mass percentage: 34.46% Si, 19.09% Ge, 46.25% O, 0.15% Bi and 0.05% Al; The wavelength of the pump laser is 830 nm.

2. The bismuth-doped aluminum silicate optical fiber amplifier according to claim 1, characterized in that: The length of the bismuth-doped aluminum silicate optical fiber is 1-5 cm.

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