OPTICAL FIBER WITH WIDE BANDWIDTH AND HIGH GAINS IN O+E BAND AND REGULATION METHOD THEREOF

Abstract

An optical fiber with wide bandwidth and high gain in an O+E band and a regulation method thereof are disclosed. The optical fiber includes a core and a cladding (0). The core includes 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) and the second loose layer (3) are made of a silica material doped with high-refractive-index GeO.sub.2 and P.sub.2O.sub.5. In the first core layer (2) and the second core layer (4), Al.sub.2O.sub.3, bismuth oxide and PbO are sequentially doped. The gain performance of the optical fiber is controlled by adjusting doping molar ratios of Al.sub.2O.sub.3, bismuth oxide and PbO. The co-doped silica optical fiber maintains fiber gains exceeding 15 dB in a wavelength range of 1260 to 1460 nm.

Claims

1. An optical fiber with wide bandwidth and high gains in an O+E band, comprising 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) and the second loose layer (3) are made of a silica material doped with high-refractive-index GeO.sub.2 and P.sub.2O.sub.5, and in the first core layer (2) and the second core layer (4), Al.sub.2O.sub.3, bismuth oxide and PbO are sequentially doped.

2. The optical fiber with wide bandwidth and high gains in an O+E band according to claim 1, wherein in the first core layer (2) and the second core layer (4), a molar ratio of Al.sub.2O.sub.3 to bismuth oxide is varied from 0.5 to 20 and a molar ratio of bismuth oxide to PbO is varied from 0.2 to 30.

3. The optical fiber with wide bandwidth and high gains in an O+E band according to claim 2, wherein in the first core layer (2) and the second core layer (4), the molar ratio of Al.sub.2O.sub.3 to bismuth oxide is varied from 1 to 3, and the molar ratio of bismuth oxide to PbO is varied from 1.2 to 2.

4. The optical fiber with wide bandwidth and high gains in an O+E band according to claim 2, wherein the cladding (0) of the optical fiber has a diameter of 120 to 130 ?m, the core has a diameter of 8 to 12 ?m, and a refractive index difference between the cladding (0) and the core is 0.005 to 0.0012.

5. A method for regulating fiber bandwidth and gain in an O+E band, comprising: depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 on an inner wall of a substrate tube to form a first loose layer (1); sequentially depositing Al.sub.2O.sub.3, bismuth oxide, and PbO on the first loose layer (1); then depositing the SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 again to form a second loose layer; sequentially depositing Al.sub.2O.sub.3, bismuth oxide, and PbO on the second loose layer; and finally, depositing a silica material doped with GeO.sub.2 and P.sub.2O.sub.5 and performing preform collapsing and fiber drawing to form an optical fiber, wherein gain performance of the optical fiber is regulated by controlling doping molar ratios of Al.sub.2O.sub.3, bismuth oxide and PbO.

6. The method for regulating fiber bandwidth and gain in an O+E band according to claim 5, wherein a molar ratio of Al.sub.2O.sub.3 to bismuth oxide is 0.5 to 20 and a molar ratio of bismuth oxide to PbO is 0.2 to 30.

7. The method for regulating fiber bandwidth and gain in an O+E band according to claim 5, wherein when an atomic layer deposition (ALD) technology is used to sequentially deposit Al.sub.2O.sub.3, bismuth oxide and PbO, an O-source precursor material is ozone or deionized water, an Al-source precursor is trimethylaluminum, a Bi-source precursor is tris(2,2,6,6-tetramethyl-3,5-heptanedionato) bismuth (Bi(tmhd).sub.3) and a Pb-source precursor is bis(2,2,6,6-tetramethyl-3,5-heptanedionato) lead (Pb(tmhd).sub.2).

8. The method for regulating fiber bandwidth and gain in an O+E band according to claim 7, wherein a Bi-source heating temperature is controlled at 200 to 300? C. with a pulse time of 200 to 400 ms; a Pb-source heating temperature is controlled at 100 to 200? C. with a pulse time of 200 to 400 ms; an O-source pulse time is 200 to 1000 ms; an Al-source pulse time is 50 to 300 ms; an entire reaction chamber maintains a uniform temperature, with a reaction temperature of 200 to 400? C. and a gas flow rate controlled at 50 to 800 sccm.

9. The method for regulating fiber bandwidth and gain in an O+E band according to claim 5, comprising the following specific steps: 1) depositing a SiO.sub.2 loose layer, which is doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing an refractive index, on an inner wall of a quartz tube by using a modified chemical vapor deposition (MCVD) technology, controlling a temperature to semi-vitrify the layer and creating an ALD deposition environment to form the first loose layer (1); 2) sequentially depositing doping materials based on a sequence of Al.sub.2O.sub.3, bismuth oxide and PbO by using the ALD technology to form a first core layer (2); 3) depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 by using the MCVD technology and semi-vitrifying the SiO.sub.2 material to form a second loose layer (3); 4) placing the substrate tube in a direction reverse to that in step 2) and performing deposition by using the ALD technology: depositing Al.sub.2O.sub.3, bismuth oxide, and PbO materials again on the second loose layer based on the deposition sequence and doping molar ratios in step 2), to form a second core layer (4); 5) by using the MCVD technology, depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing the refractive index, semi-vitrifying the deposited material to form an inner core (5), finally, performing high-temperature preform collapsing and drawing a fiber preform into an optical fiber by using a drawing tower.

10. The method for regulating fiber bandwidth and gain in an O+E band according to claim 6, comprising the following specific steps: 1) depositing a SiO.sub.2 loose layer, which is doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing an refractive index, on an inner wall of a quartz tube by using a modified chemical vapor deposition (MCVD) technology, controlling a temperature to semi-vitrify the layer and creating an ALD deposition environment to form the first loose layer (1); 2) sequentially depositing doping materials based on a sequence of Al.sub.2O.sub.3, bismuth oxide and PbO by using the ALD technology to form a first core layer (2); 3) depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 by using the MCVD technology and semi-vitrifying the SiO.sub.2 material to form a second loose layer (3); 4) placing the substrate tube in a direction reverse to that in step 2) and performing deposition by using the ALD technology: depositing Al.sub.2O.sub.3, bismuth oxide, and PbO materials again on the second loose layer based on the deposition sequence and doping molar ratios in step 2), to form a second core layer (4); 5) by using the MCVD technology, depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing the refractive index, semi-vitrifying the deposited material to form an inner core (5), finally, performing high-temperature preform collapsing and drawing a fiber preform into an optical fiber by using a drawing tower.

11. The method for regulating fiber bandwidth and gain in an O+E band according to claim 7, comprising the following specific steps: 1) depositing a SiO.sub.2 loose layer, which is doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing an refractive index, on an inner wall of a quartz tube by using a modified chemical vapor deposition (MCVD) technology, controlling a temperature to semi-vitrify the layer and creating an ALD deposition environment to form the first loose layer (1); 2) sequentially depositing doping materials based on a sequence of Al.sub.2O.sub.3, bismuth oxide and PbO by using the ALD technology to form a first core layer (2); 3) depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 by using the MCVD technology and semi-vitrifying the SiO.sub.2 material to form a second loose layer (3); 4) placing the substrate tube in a direction reverse to that in step 2) and performing deposition by using the ALD technology: depositing Al.sub.2O.sub.3, bismuth oxide, and PbO materials again on the second loose layer based on the deposition sequence and doping molar ratios in step 2), to form a second core layer (4); 5) by using the MCVD technology, depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing the refractive index, semi-vitrifying the deposited material to form an inner core (5), finally, performing high-temperature preform collapsing and drawing a fiber preform into an optical fiber by using a drawing tower.

12. The method for regulating fiber bandwidth and gain in an O+E band according to claim 8, comprising the following specific steps: 1) depositing a SiO.sub.2 loose layer, which is doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing an refractive index, on an inner wall of a quartz tube by using a modified chemical vapor deposition (MCVD) technology, controlling a temperature to semi-vitrify the layer and creating an ALD deposition environment to form the first loose layer (1); 2) sequentially depositing doping materials based on a sequence of Al.sub.2O.sub.3, bismuth oxide and PbO by using the ALD technology to form a first core layer (2); 3) depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 by using the MCVD technology and semi-vitrifying the SiO.sub.2 material to form a second loose layer (3); 4) placing the substrate tube in a direction reverse to that in step 2) and performing deposition by using the ALD technology: depositing Al.sub.2O.sub.3, bismuth oxide, and PbO materials again on the second loose layer based on the deposition sequence and doping molar ratios in step 2), to form a second core layer (4); 5) by using the MCVD technology, depositing a SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 for increasing the refractive index, semi-vitrifying the deposited material to form an inner core (5), finally, performing high-temperature preform collapsing and drawing a fiber preform into an optical fiber by using a drawing tower.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic structural diagram of an optical fiber prepared according to the present disclosure;

[0028] FIG. 2 is a schematic diagram of spectral width of the optical fiber prepared according to the present disclosure;

[0029] FIG. 3 is a schematic diagram of gain of the optical fiber prepared according to the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present disclosure will be described in detail below with reference to the drawings and specific embodiments.

Embodiment

[0031] Referring to FIG. 2 and FIG. 3, a method for regulating the gain and bandwidth of a bismuth-doped silica optical fiber is provided. Firstly, a SiO.sub.2 loose layer doped with high-refractive-index GeO.sub.2 and P.sub.2O.sub.5 was deposited on an inner wall of a quartz tube by using an MCVD technology and semi-vitrified to form the first loose layer 1. Then, doping materials were deposited based on a sequence of Al.sub.2O.sub.3, bismuth oxide and PbO by using an ALD technology to form the first core layer 2. During this process, deposition parameters such as deposition temperature, precursor pulse time, vapor pressure and deposition cycles during the ALD were controlled to precisely control deposition concentrations of various doping materials, achieving a molar ratio of Al.sub.2O.sub.3 to bismuth oxide being 0.5 to 10 and a molar ratio of bismuth oxide to PbO being 0.2 to 15. A SiO.sub.2 material doped with GeO.sub.2 and P.sub.2O.sub.5 was deposited and semi-vitrified to form the second loose layer 3. Then, Al.sub.2O.sub.3, bismuth oxide and PbO materials were deposited on the second loose layer again based on the same deposition sequence and doping molar ratios by using the ALD technology to form the second core layer 4. Finally, a silica material doped with high-refractive-index GeO.sub.2 and P.sub.2O.sub.5 was deposited by using the MCVD technology and semi-vitrified to form the inner core 5. Further, preform collapsing at high-temperature was performed and an optical fiber preform was drawn by using a drawing tower to form an optical fiber.

[0032] Fluorescence intensity with different doping ratios is shown in the table below:

TABLE-US-00001 Fluorescence Intensity Optical fiber Al/Bi Bi/Pb (dBm) 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

[0033] From the table, it can be observed that by adjusting the molar ratios of Al.sub.2O.sub.3, bismuth oxide and PbO, the gain performance of the optical fiber can be controlled. When both Al/Bi and Bi/Pb molar ratios are in the range of 1-2, the fluorescence intensity can effectively be increased.