Optical fiber with wide bandwidth and high gain in o + e band and method for regulating the same

Abstract

The application discloses a kind of optical fiber and its regulation method with wide bandwidth and high gain in O+E band, including core and cladding (0), core includes first loose layer (1) from outside to inside, first core layer (2), second loose layer (3), second core layer (4) and inner core (5), first loose layer (1), second loose layer (3) are made of quartz material doped with high refractive index GeO2 and P2O5, first core layer (2) and second core layer (4) are doped with Al2O3, bismuth oxide and PbO in order;The gain performance of optical fiber is regulated by regulating the doping molar ratio of Al2O3, bismuth oxide and PbO.The common-doped quartz optical fiber has a gain greater than 15dB in the wavelength range of 1260-1460nm, especially at 1420nm, the gain can reach more than 20dB.The optical fiber structure is simple, the doping concentration is uniform and controllable, and can be widely used in active optical fiber amplifier, high-order vortex light amplifier, fiber laser, fiber sensor and other fields.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical fiber structure and a performance regulation method thereof. BACKGROUND

[0002] With the rapid development of big data and the Internet, the capacity demand of optical fiber communication system is growing explosively. At this time, the improvement of the performance of optical fiber amplifier is of great significance to the development of optical communication system. Due to the 4f-4f orbital limitation, the gain bandwidth of traditional erbium-doped silica optical fiber is limited to about 35nm, which is urgent to break through in other wave bands for the development of optical communication system.

[0003] In recent years, Bi-doped optical fiber has shown wideband fluorescence characteristics in the near-infrared wave band, which has attracted widespread attention and research. According to the core composition, structure and pump wavelength, Bi-doped fiber amplifier can provide gain in the range of 1000nm-1600nm. Compared with rare earth (RE) ions, the optical transition in BACs (Bi-related active centers) is related to the non-screened outer electron shell of Bi atom or ion. Therefore, the wavelength of transition and the structure of energy level depend largely on the matrix of the host glass. By changing the composition of the host glass, the emission wavelength range and the optical amplification range of Bi-doped glass can be changed. In addition, lead element is adjacent to bismuth element in the periodic table of elements, and both have similar outer electron structure. After investigation and research, it is found that lead-doped glass material has similar luminescence characteristics and active centers as bismuth. Therefore, on the basis of bismuth-doped silica optical fiber, lead is introduced to further explore the luminescence efficiency and other problems of different bismuth-related luminescence centers. By using ALD technology and MCVD technology, an O+E wave band ultra-wideband, high-gain Bi / P / Ge / Pb co-doped silica optical fiber amplifier is developed.

[0004] In 2015, Chinese patent 201510941655.3 proposed using ALD technology to alternately deposit Bi and Er ions or Bi, Er and Al ions into the fiber core to prepare a Bi / Er or Bi / Er / Al co-doped quartz optical fiber, which can realize ultra-wideband amplification in the 1000-1380nm and 1450-1800nm wavebands. In the same year, Chinese patent 201510026738.X proposed a method for preparing a tube-melt co-drawing bismuth-doped optical fiber. Although it avoids the fluorescence quenching of the optical fiber caused by the agglomeration of bismuth ions in the tube rod method, the preparation process requires strict temperature and other condition control, greatly increasing the difficulty of preparation. In 2019, Chinese patent 201980059860.3 shows and describes a bismuth-doped optical fiber and a bismuth-doped optical fiber amplifier. However, its gain bandwidth in the O waveband is relatively narrow, limited to 1270-1310nm, and is greatly affected by the system structure. In 2020, Chinese patent 202010073619.0 proposes to prepare a Bi / Er / La / Al co-doped quartz optical fiber based on high-temperature doping, improved chemical vapor deposition (MCVD) and ALD or liquid doping process, high-temperature evaporation doping process, and external vapor deposition process. The optical fiber exhibits broadband fluorescence in the 1530-1625nm range, and the gain in the C+L waveband is 10-35dB. However, the present patent mainly introduces lead based on bismuth-doped quartz optical fiber, and further explores the light emission efficiency and wide-spectrum gain characteristics of different bismuth-related light emission centers. Using ALD technology and MCVD technology, an O+E waveband ultra-wideband, high-gain Bi / P / Ge / Pb co-doped quartz optical fiber and optical fiber amplifier and optical fiber laser are developed. SUMMARY

[0005] The present application aims to solve the problems of difficult expansion of erbium-doped quartz optical fiber gain bandwidth, narrow O+E waveband optical fiber gain bandwidth, high temperature requirement in the preparation process, difficult preparation, and great influence of system structure. A method for regulating the local field of active particles and improving the gain performance of optical fibers is provided.

[0006] The application breaks through the limitation of the previous O+E band width. By regulating the co-doping of Bi and Pb elements, the formation of BAC-P and PAC-P is promoted, and the light emitting efficiency in the range of 1260nm-1360nm is enhanced. In addition, by regulating the doping content of Ge element, the expansion of the gain bandwidth in the range of 1360nm-1460nm is realized while ensuring the light emitting efficiency in the range of 1260nm-1360nm. The ALD technology can realize the precise control of material doping concentration from the atomic layer, and the doping uniformity is good, and the doping elements are multiple. The Bi / P / Ge / Pb co-doped quartz optical fiber prepared by the method has an optical fiber gain greater than 15dB in the wavelength range of 1260nm-1460nm, and the maximum gain can reach 20-40dB at 1420nm.

[0007] The technical scheme of the application comprises the following steps:

[0008] An optical fiber with wide bandwidth and high gain in O+E band comprises a core and a cladding 0, wherein the core comprises a first loose layer 1, a first core layer 2, a second loose layer 3, a second core layer 4 and an inner core 5 from outside to inside, the first loose layer 1, the second loose layer 3 and the inner core 5 are composed of quartz material doped with high refractive index GeO2 and P2O5, and the first core layer 2 and the second core layer 4 are doped with Al2O3, bismuth oxide and PbO in sequence.

[0009] The molar ratio of Al2O3 to bismuth oxide in the first core layer 2 and the second core layer 4 is 0.5-20, and the molar ratio of bismuth oxide to PbO is 0.2-30.

[0010] The diameter of the cladding 0 of the optical fiber is 120-130μm, the diameter of the core is 8-12μm, and the refractive index difference between the cladding 0 and the core is 0.005-0.0012.

[0011] The application relates to a method for adjusting the O+E waveband bandwidth and gain of an optical fiber, which comprises the following steps: firstly, depositing SiO2 material doped with GeO2 and P2O5 on the inner wall of a base pipe to form a first loose layer 1, then depositing Al2O3, bismuth oxide and PbO on the first loose layer 1 in sequence, and then depositing SiO2 material doped with GeO2 and P2O5 again to form a second loose layer, depositing Al2O3, bismuth oxide and PbO on the second loose layer in sequence, and finally depositing quartz material doped with GeO2 and P2O5, and then drawing the rod into an optical fiber. The deposition sequence and doping ratio of Al2O3, bismuth oxide, PbO, P2O3 and GeO2 are controlled to control the local field distribution of the doped ions and the matrix material, so that the light emitting efficiency and gain intensity of the optical fiber are improved, the gain spectrum width is expanded, and the gain performance of the optical fiber is improved.

[0012] The molar ratio of Al2O3 to bismuth oxide is 0.5-20, and the molar ratio of bismuth oxide to PbO is 0.2-30.

[0013] When the ALD technology is used to deposit Al2O3, bismuth oxide and PbO in sequence, the O source precursor material is ozone or deionized water, the Al source precursor is trimethylaluminum, the Bi source precursor is tris(2,2,6,6-tetramethyl-3,5-heptanedionate) bismuth (Bi(tmhd)3), and the Pb source precursor is bis(2,2,6,6,-tetramethyl-3,5-heptanedionate) lead (Pb(tmhd)2).

[0014] The Bi source heating temperature is controlled to be 200-300 DEG C, and the pulse time is 200-400 ms; the Pb source heating temperature is controlled to be 100-200 DEG C, and the pulse time is 200-400 ms; the O source pulse time is 200-1000 ms; the Al source pulse time is 50-300 ms; the temperature of the whole reaction cavity is uniform, the reaction temperature is 200-400 DEG C, and the gas flow rate is controlled to be 50-800 sccm.

[0015] The specific steps are as follows:

[0016] 1) The MCVD technology is used to deposit SiO2 material doped with GeO2 and P2O5 on the inner wall of a quartz pipe for improving the refractive index, and the temperature is controlled to semi-glassify the material, so that an ALD deposition environment is created, and a first loose layer 1 is formed;

[0017] 2) The ALD technology is used to deposit doped materials in sequence according to the sequence of Al2O3, bismuth oxide and PbO, and a first core layer 2 is formed;

[0018] 3) The MCVD technology is used to deposit SiO2 material doped with GeO2 and P2O5 on the doped material, and the material is semi-glassified, so that a second loose layer 3 is formed;

[0019] 4) Using ALD technology, the base pipe is reversely placed and deposited with step 2 to further increase the doping uniformity. Al2O3, bismuth oxide, PbO material is deposited again on the second loose layer according to the deposition sequence and doping molar ratio in step 2 to form a second core layer 4;

[0020] 5) GeO2, P2O5 doped SiO2 material with increased refractive index is deposited by using MCVD technology, and is semi-glassified as an inner fiber core (5). Finally, high-temperature rod shrinking is performed, and the optical fiber preform rod is drawn into an optical fiber by using a drawing tower.

[0021] The beneficial effects of the present application are:

[0022] 1. Al2O3, bismuth oxide and PbO material is sequentially deposited in the fiber core part by using atomic layer deposition technology, the molar ratio of Al2O3 to bismuth oxide is about 0.5-20, and the molar ratio of bismuth oxide to PbO is 0.2-30. The gain performance of the optical fiber is adjusted by adjusting the doping molar ratio of Al2O3, bismuth oxide and PbO.

[0023] 2. The Bi / Pb / P / Ge co-doped quartz optical fiber has multiple absorption peaks in the wavelength range of 400-1700 nm, and the Bi-related absorption peak near 1000 nm is widened.

[0024] 3. The Bi / Pb / P / Ge co-doped quartz optical fiber has an optical fiber gain greater than 15 dB in the wavelength range of 1260-1460 nm, and the gain can reach more than 20 dB at 1420 nm.

[0025] 4. The optical fiber has a simple structure, uniform and controllable doping concentration, and can be widely used in the fields of active optical fiber amplifiers, high-order vortex light amplifiers, optical fiber lasers, optical fiber sensors and the like. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic diagram of the optical fiber prepared by the present application.

[0027] Figure 2 is a spectral width schematic diagram of the optical fiber prepared by the present application.

[0028] Figure 3 is a gain schematic diagram of the optical fiber prepared by the present application. DETAILED DESCRIPTION

[0029] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0030] Embodiment:

[0031] Reference Figure 2 and Figure 3The application discloses a method for regulating gain size and bandwidth width of a bismuth-doped quartz optical fiber, and the method comprises the following steps: firstly, a loose layer of SiO2 doped with high refractive index GeO2 and P2O5 is deposited on the inner wall of a quartz tube by using MCVD technology, and the loose layer is semi-glassified to form a first loose layer 1; secondly, doped materials are sequentially deposited in the order of Al2O3, bismuth oxide and PbO by using ALD technology to form a first core layer 2, and in the process, deposition parameters such as deposition temperature, precursor pulse time, vapor pressure and deposition period of the ALD process are controlled to accurately control the deposition concentration of various doped materials, so that the molar ratio of Al2O3 to bismuth oxide is 0.5-10, and the molar ratio of bismuth oxide to PbO is 0.2-15; SiO2 material doped with GeO2 and P2O5 is deposited on the doped materials by using MCVD technology, and the material is semi-glassified to form a second loose layer 3; then, Al2O3, bismuth oxide and PbO materials are deposited again on the second loose layer in the above-mentioned deposition order and doping molar ratio by using ALD technology to form a second core layer 4; finally, quartz material doped with high refractive index GeO2 and P2O5 is deposited by using MCVD technology, and the material is semi-glassified to form an inner core 5, and the optical fiber preform rod is drawn into an optical fiber by using a drawing tower after further high-temperature rod shrinking.

[0032] The fluorescent intensities under different doping ratios are as shown in the following table.

[0033] Optical fiber Al / Bi Bi / Pb Fluorescence intensity (dB) BDF-1 3 1.2 -50 BDF-2 5.3 14 -56 BDF-3 2 1.9 -38 BDF-4 1.3 1.8 -30 BDF-5 1.5 1.7 -26

[0034] It can be seen from the table that the gain performance of the optical fiber can be regulated by regulating the doping molar ratio of Al2O3, bismuth oxide and PbO, and the fluorescent intensity can be effectively improved when the molar ratio of Al / Bi and Bi / Pb is in the range of 1-2.

Claims

1. An optical fiber having a wide bandwidth and a high gain in an O+E band, comprising a core and a cladding (0), characterized in that: The fiber core comprises, from outside to inside, a first loose layer (1), a first core layer (2), a second loose layer (3), a second core layer (4) and an inner core (5), the first loose layer (1) and the second loose layer (3) are made of quartz material doped with high refractive index GeO2 and P2O5, Al2O3, bismuth oxide and PbO are sequentially deposited in the first core layer (2) and the second core layer (4) by using ALD technology, and the molar ratio of Al2O3 to bismuth oxide in the first core layer (2) and the second core layer (4) is 0.5-20, and the molar ratio of bismuth oxide to PbO is 0.2-30.

2. The optical fiber having wide bandwidth and high gain in O+E bands according to claim 1, wherein: The cladding layer (0) of the optical fiber has a diameter of 120-130 μm, the core has a diameter of 8-12 μm, and the refractive index difference between the cladding layer (0) and the core is 0.005-0.0012.

3. A method for adjusting the O+E band bandwidth and gain of an optical fiber, characterized by: First, a SiO2 material doped with GeO2 and P2O5 is deposited on the inner wall of the base pipe to form a first loose layer (1), Al2O3, bismuth oxide and PbO are sequentially deposited on the first loose layer (1), then a SiO2 material doped with GeO2 and P2O5 is again deposited to form a second loose layer, Al2O3, bismuth oxide and PbO are sequentially deposited on the second loose layer, and finally a quartz material doped with GeO2 and P2O5 is deposited, and the rod is drawn into an optical fiber, the doping molar ratio of Al2O3, bismuth oxide and PbO is adjusted to control the gain performance of the optical fiber, the molar ratio of Al2O3 to bismuth oxide is 0.5-20, and the molar ratio of bismuth oxide to PbO is 0.2-30.

4. The method for adjusting the bandwidth and gain of an optical fiber in the O+E band according to claim 3, characterized in that: When Al2O3, bismuth oxide and PbO are sequentially deposited by using ALD technology, the O source precursor material used is ozone or deionized water, the Al source precursor is trimethylaluminum, the Bi source precursor is tris(2,2,6,6-tetramethyl-3,5-heptanedionate) bismuth, and the Pb source precursor is bis(2,2,6,6,-tetramethyl-3,5-heptanedionate) lead.

5. The method for adjusting the bandwidth and gain of an optical fiber in the O+E band according to claim 4, characterized in that: The Bi source heating temperature is controlled at 200-300℃, the pulse time is 200-400 ms; the Pb source heating temperature is controlled at 100-200℃, the pulse time is 200-400 ms; the O source pulse time is 200-1000 ms; the Al source pulse time is 50-300 ms; the temperature of the whole reaction cavity is uniform, the reaction temperature is 200-400℃, and the gas flow rate is controlled at 50-800 sccm.

6. The method of claim 3-5, wherein the adjustment of the O+E band bandwidth and gain of the optical fiber is performed by adjusting the temperature of the optical fiber. The specific steps are as follows: 1) A SiO2 loose layer doped with GeO2, P2O5 and SiO2 for increasing the refractive index is deposited on the inner wall of the quartz tube by using MCVD technology, and the temperature is controlled to semi-glassify it to create an ALD deposition environment and form a first loose layer (1); 2) The doped material is sequentially deposited in the order of Al2O3, bismuth oxide and PbO by using ALD technology to form a first core layer (2); 3) A SiO2 material doped with GeO2 and P2O5 is deposited on the doped material by using MCVD technology, and it is semi-glassified to form a second loose layer (3); 4) using ALD technology, the base pipe is reversely placed and deposited on the second loose layer, Al2O3, bismuth oxide, PbO material is deposited again according to the deposition sequence and doping molar ratio in step 2), forming a second core layer (4); 5) using MCVD technology to deposit GeO2, P2O5 doped SiO2 material to increase the refractive index, and semi-glassifying as an inner core (5), finally, high temperature rod shrinking, and using a drawing tower to draw the optical fiber preform rod into an optical fiber.

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