1. The utility model provides an ultra wide band fluorescence quantum dot doping quartz amplification fiber, includes fibre core (1) and cladding (2), its characterized in that: the fiber core (1) is doped with semiconductor quantum dots.

2. The ultra-wideband fluorescent quantum dot doped quartz amplifying fiber of claim 1, wherein: the fiber core (1) comprises a silicon dioxide loose layer (1-1) on the outer layer and a doping layer (1-2) in the middle part, the semiconductor quantum dots are arranged in the doping layer (1-2), and the doping layer (1-2) is also doped with Al₂O₃And GeO₂。

3. The ultra-wideband fluorescent quantum dot doped quartz amplifying fiber of claim 1, wherein: the semiconductor quantum dots are one or more of PbS, PbSe and PbTe.

4. The ultra-wideband fluorescent quantum dot doped quartz amplifying fiber of claim 3, wherein: GeO is doped in the silicon dioxide loose layer (1-1)₂。

5. The ultra-wideband fluorescent quantum dot doped quartz amplifying fiber of claim 4, wherein: the doping layer (1-2) is combined with an atomic layer deposition technology and an in-situ annealing technology to prepare semiconductor quantum dots with different sizes, the size range of the quantum dots is 1.0-50.0 nm, and the concentration range is 0.01-5.0 mol%.

6. The ultra-wideband fluorescent quantum dot doped silica amplifying fiber according to any one of claims 1 to 5, wherein: the diameter of the fiber core (1) is 5.0-50.0 μm, the diameter of the cladding (2) is 125.0-300.0 μm, the refractive index difference between the fiber core (1) and the cladding (2) is 0.2-3%, the absorption wavelength range of the optical fiber is 200-2000 nm, and the fluorescence spectrum range is 400-2500 nm.

7. A preparation method of an ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber is characterized by comprising the following steps:

firstly, depositing a cladding (2) and a silicon dioxide loose layer (1-1) on a quartz base tube by using an improved chemical vapor deposition method to reach a semitransparent glass state at a high temperature;

alternately depositing one or two or three quantum dots of PbS, PbSe and PbTe on the inner tube wall;

thirdly, repeating the second step, controlling the concentration of different quantum dot materials and the size of the quantum dots through the deposition cycle period,

forming a doped layer (1-2);

fourthly, placing the deposited quartz base tube in a vacuum or nitrogen atmosphere for in-situ annealing;

depositing a proper amount of aluminum oxide and germanium oxide co-doped material;

sixthly, performing rod shrinkage treatment on the quartz base tube to form an optical fiber preform;

and seventhly, drawing the optical fiber.

8. The preparation method of the ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber according to claim 7, characterized by comprising the following steps: in the second step and the third step, the gas-phase precursor of the Pb source is: bis (2,2,6,6-tetramethyl-3,5-heptanedionato) lead, Pb (TMHD)₂(ii) a The precursor material of the S source is H₂S and N₂Mixture of (A) and (B), H₂The concentration of S is 1-15%; the gas phase precursor of the Se source used is ((Et)₃Si)₂Se); the vapor phase precursor of the Te source used was ((Et)₃Si)₂Te)。

9. The preparation method of the ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber according to claim 8, characterized by comprising the following steps: the heating temperature of a Pb source is controlled to be 80-200 ℃, the pulse time of the Pb source is 100-500 ms, the purging time is 0.5-10 s, and the temperature of a corresponding reaction substrate is 150-300 ℃; the pulse time of the S, Se or Te source is 10-500 ms, and the purging time is 0.5-10S.

10. The preparation method of the ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber according to claim 8, characterized by comprising the following steps: the cycle period of the third step is 10-2000 cycles, the deposition concentration of the semiconductor quantum dot material is 0.01-5.0 mol%, the deposition thickness of the aluminum oxide and germanium oxide co-doped material is 100-1000 nm, the concentration range of Al ions is controlled to be 0.2-10 mol%, and the concentration range of Ge ions is controlled to be 0.5-10 mol%.

Background

Due to the development of an ultra-high-speed, large-capacity and long-distance optical fiber communication system, new requirements on the power, bandwidth and gain flatness of an optical fiber amplifier are provided, so that a doping source which is large in fluorescence coverage range, easy to analyze a light-emitting mechanism, wide in gain bandwidth and good in gain flatness is doped into an optical fiber, and the preparation of a novel doped optical fiber is not easy. Currently, researchers have observed the phenomenon of light emission in quantum dot materials. According to the characteristics of the quantum dot material, when the size of each dimension of the quantum dot material is reduced to a nanometer level, photons with different wavelengths can be emitted by adjusting the particle size of the quantum dot after the quantum dot is activated. This property has attracted the interest of many researchers and has been studied, successfully applying this material to many fields. The coverage range of the radiation spectrum of the quantum dot materials such as lead selenide (PbSe), lead sulfide (PbS), lead telluride (PbTe) and the like can reach the band of 450-2500nm, and the window of the optical communication system can be comprehensively covered.

At present, quantum dot materials with broadband radiation characteristics can be obtained in the following two ways. Firstly, the same quantum dot material but multi-size distribution can be obtained through the regulation of conditions such as growth temperature and time of the quantum dots, and the emission spectrum with wide bandwidth can be formed through combination. Secondly, the bandwidth and the light-emitting position of the whole material can be regulated and controlled through the combined doping among different kinds of quantum dot materials. Compared with the fixed non-adjustable emission characteristic of most rare earth ions, the quantum dot can realize adjustable broadband emission at different wave bands, and the characteristic of the quantum dot is applied to biological detection, electronic screen display and photoelectric devices and can be used as an effective gain medium of a broadband optical fiber amplifier. Therefore, by combining the atomic layer deposition technology and the in-situ annealing technology, the semiconductor quantum dots with different sizes are prepared in the optical fiber doping process, the ultra-wideband fluorescent quantum dot doped optical fiber is prepared, the ultra-wideband fluorescent coverage range is realized, and the requirements of an optical communication system on the bandwidth and the waveband can be met.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the problems of the bandwidth shortage and the non-adjustable emission characteristic of the prior rare earth element doped amplification optical fiber, the ultra-wideband fluorescence optical fiber doped with quantum dots and the preparation method are provided.

The technical scheme of the invention is as follows:

an ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber comprises a fiber core and a cladding, wherein semiconductor quantum dots are doped in the fiber core.

The fiber core comprises a silicon dioxide loose layer on the outer layer and a doped layer in the middle, the silicon dioxide loose layer is made of high-purity silicon dioxide or silicon dioxide material doped with GeO2 with certain concentration and high refractive index, one or more quantum dots of PbS, PbSe and PbTe are doped in the doped layer, and Al is doped in the doped layer₂O₃And GeO₂。

And preparing semiconductor quantum dots with different sizes in the doping layer by combining an atomic layer deposition technology and an in-situ annealing technology, wherein the size range of the quantum dots is 1.0-50.0 nm, and the concentration range is 0.01-5.0 mol%.

The cladding is composed of a pure silica material having a lower refractive index than the core.

The optical fiber parameters are as follows: the diameter of the fiber core is 5.0-50.0 μm, the diameter of the cladding is 125.0-300.0 μm, the difference of the refractive index of the fiber core and the refractive index of the cladding is 0.2-3%, the absorption wavelength range of the optical fiber is 200-2000 nm, and the fluorescence spectrum range is 400-2500 nm.

A preparation method of an ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber comprises the following steps:

depositing a cladding and a silica loose layer on a quartz base tube by using an improved chemical vapor deposition method at a high temperature to a semitransparent glass state;

alternately depositing one or two or three quantum dots of PbS, PbSe and PbTe on the inner tube wall, wherein the deposition concentration of the semiconductor quantum dot material is 0.01-5.0 mol%;

repeating the second step, controlling the distribution condition of the doped particles through a deposition cycle period, and forming a doped layer;

fourthly, placing the deposited quartz base tube in a vacuum or nitrogen atmosphere for in-situ annealing;

depositing a proper amount of aluminum oxide and germanium oxide co-doped material, wherein the deposition thickness of the aluminum oxide and germanium oxide co-doped material is 100-1000 nm, the concentration range of Al ions is controlled to be 0.2-10 mol%, and the concentration range of Ge ions is controlled to be 0.5-10 mol%;

sixthly, performing rod shrinkage treatment on the quartz base tube to form an optical fiber preform;

and seventhly, drawing the optical fiber.

The gas phase precursor of the Pb source used in the second step is as follows: bis (2,2,6,6-Tetramethyl-3, 5-heptanedionate) lead, Bis (2,2,6,6-Tetramethyl-3, 5-heptanedionate) lead (II), Pb (TMHD)₂(ii) a The precursor material of the S source is H₂S and N₂Mixture of (A) and (B), H₂The concentration of S is 1-15%; the gas phase precursor of the Se source used is (Et)₃Si)₂Se); the vapor phase precursor of the Te source used was ((Et)₃Si)₂Te)。

The heating temperature of a Pb source is controlled to be 80-200 ℃, the pulse time of the Pb source is 100-500 ms, the purging time is 0.5-10 s, and the temperature of a corresponding reaction substrate is 150-300 ℃; the corresponding reaction substrate temperature is 100-400 ℃; the pulse time of the S, Se or Te source is 10-500 ms, and the purging time is 0.5-10S.

The invention has the beneficial effects that:

by utilizing the advantages of the combination of an Atomic Layer Deposition (ALD) technology and an in-situ annealing technology, semiconductor quantum dot materials with different sizes are combined with optical fiber preparation, and the ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber and the preparation method thereof are provided. The size and the band gap of the semiconductor quantum dot material are regulated and controlled by changing the deposition temperature, the deposition period, the annealing temperature and the annealing time, so that the light emission spectra are combined to form a fluorescence spectrum with wide bandwidth. Under the size of the quantum dots, broadband radiation in a common communication waveband can be realized through quantum dot materials with multiple size distributions and different combinations. The quantum dot doped silica fiber has the following advantages: firstly, due to the quantum confinement effect, the light-emitting position and bandwidth of the quantum dot can be controlled by the size of the quantum dot, so that the active waveband of the quantum dot doped optical fiber can be tuned to a common communication port. The advantage can fill the bandwidth deficiency of the rare earth element doped amplifying fiber. In addition, although the non-uniform broadening of the quantum dot material is not beneficial to the application of the quantum dot doped fiber in a laser, the applied wave band can be broadened in an optical amplifier, and then the quantum dot doped quartz fiber amplifier with the wide bandwidth characteristic is built. In addition, due to the fact that the size of the quantum dot material is small, scattering loss in the prepared quantum dot doped silica optical fiber is small, and the loss is mainly determined by absorption of the quantum dots doped in the fiber core. Therefore, the multi-size fluorescent quantum dot doped optical fiber taking the quartz material as the substrate has the advantages of the quantum dot material, and the quartz substrate material and the waveguide structure of the optical fiber enable the quantum dot doped quartz optical fiber to have the advantages of being small in insertion loss, easy to weld and the like when applied to a communication system. In today's optical communication networks, doped optical fibers based on quantum dot materials have become a research hotspot. Compared with other doped optical fibers, the multi-size ultra-wideband fluorescent quantum dot doped silica optical fiber has incomparable advantages in bandwidth and regulation and control, and has application prospects in the fields of ultra-wideband spectrum, low loss and low noise silica doped optical fiber amplifiers. Compared with the prior art, the invention has the following obvious substantive and significant advantages:

1) by combining the ALD technology and the in-situ annealing technology, the size of the quantum dot can be accurately regulated, and the deposited quantum dot material has the advantages of better uniformity, high density, controllable concentration, good dispersibility and less material defects;

2) the ultra-wideband fluorescent quantum dot doped quartz amplification optical fiber has the characteristics of wide fluorescence coverage range, wide gain spectrum, low overall loss, low noise coefficient and the like;

3) the structure is simple, the cost is low, the industrial production is easy, and the ultra-wideband fiber amplifier can be used for constructing ultra-wideband light sources, fiber amplifiers and the like.

Drawings

FIG. 1 is a block diagram of the architecture of one embodiment of the present invention.

FIG. 2 is a block diagram of the core structure according to one embodiment of the present invention.

Fig. 3 is a schematic diagram of an alternate deposition of a co-doped quantum dot material by an atomic layer deposition technique according to an embodiment of the invention.

Fig. 4 is a process flow diagram of alternate deposition of multi-sized quantum dot materials by combining atomic layer deposition and in-situ annealing according to an embodiment of the invention.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

The ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber comprises a fiber core and a cladding, wherein the fiber core comprises a silica loose layer on the outer layer and semiconductor quantum dot material layers with different sizes and uniformly distributed in the middle; the cladding is made of pure quartz material; the core is located in the middle of the cladding.

The silicon dioxide loose layer is high-purity silicon dioxide or is doped with certain concentration of high-refractive index GeO₂The silica material of (1).

The semiconductor quantum dot material layer is one or two or three quantum dots of PbS, PbSe and PbTe and aluminum oxide Al₂O₃With germanium oxide GeO of increasing refractive index profile₂A material.

The semiconductor quantum dot material layer is prepared by combining an Atomic Layer Deposition (ALD) technology and an in-situ annealing technology, and the semiconductor quantum dots with different sizes are prepared, wherein the size range of the quantum dots is 1.0-50.0 nm, and the concentration range of the quantum dots is 0.01-5.0 mol%.

The cladding is composed of a pure silica material having a lower refractive index than the core.

The optical fiber parameters are as follows: the diameter of the fiber core (1) is 5.0-50.0 μm, the diameter of the cladding (2) is 125.0-300.0 μm, the refractive index difference between the fiber core (1) and the cladding (2) is 0.2-3%, the absorption wavelength range of the optical fiber is 200-2000 nm, and the fluorescence spectrum range is 400-2500 nm.

A preparation method of an ultra wide band fluorescent quantum dot doped quartz amplifying optical fiber is used for manufacturing the ultra wide band fluorescent quantum dot doped quartz amplifying optical fiber and comprises the following steps:

1) firstly, depositing a cladding layer and a silica loose layer by using a Modified Chemical Vapor Deposition (MCVD) method to reach a semitransparent glass state at a high temperature;

2) then, uniformly, circularly and alternately depositing one or two or three quantum dots of PbS, PbSe and PbTe in the quartz substrate tube by utilizing an Atomic Layer Deposition (ALD) technology;

3) repeating the process of 2), and controlling the concentration of the doped different quantum dot materials and the size of the quantum dots through a deposition cycle period;

4) placing the deposited quartz base tube in a vacuum or nitrogen atmosphere for in-situ annealing at the annealing temperature of 100-500 ℃ for 10-60 min, and adjusting the size range of the quantum dots to be 1.0-50.0 nm by controlling the annealing temperature and the annealing time;

5) depositing a proper amount of aluminum oxide and germanium oxide co-doped material;

6) performing rod shrinkage treatment on the deposition cladding and the fiber core quartz base tube by MCVD technology to form fluorescent quantum dot doped quartz amplification optical fiber prefabricated rods with different sizes;

7) and finally, drawing the fluorescent quantum dot doped quartz amplifying optical fiber prefabricated rods with different sizes into the ultra-wideband fluorescent quantum dot doped quartz amplifying optical fiber by using a drawing tower.

The cycle period in the step 3) is 10-2000 cycles.

The gas-phase precursor of the Pb source for uniformly, circularly and alternately depositing one or two or three quantum dot materials (1-2) in the PbS, PbSe and PbTe in the step 2) and the step 3) is as follows: bis (2,2,6,6-Tetramethyl-3, 5-heptanedionate) lead, Bis (2,2,6,6-Tetramethyl-3, 5-heptanedionate) lead (II), Pb (TMHD)₂(ii) a The precursor material of the S source is H₂S and N₂Mixture of (A) and (B), H₂The concentration of S is 1-15%; the gas phase precursor of the Se source used is (Et)₃Si)₂Se); the vapor phase precursor of the Te source used was ((Et)₃Si)₂Te)。

The step 2) and the step 3) are carried out to uniformly, circularly and alternately deposit one or two or three quantum dot materials (1-2) of PbS, PbSe and PbTe, the heating temperature of a Pb source is controlled to be 80-200 ℃, the pulse time of the Pb source is 100-500 ms, the purging time is 0.5-10 s, and the temperature of a corresponding reaction substrate is 150-300 ℃; the corresponding reaction substrate temperature is 100-400 ℃; the pulse time of the S, Se or Te source is 10-500 ms, and the purging time is 0.5-10S.

The deposition concentration of the semiconductor quantum dot material in the step 2) and the step 3) is 0.01-5.0 mol%.

The deposition thickness of the aluminum oxide and germanium oxide co-doped material in the step 5) is 100-1000 nm, the concentration range of Al ions is controlled to be 0.2-10 mol%, and the concentration range of Ge ions is controlled to be 0.5-10 mol%.

Example 1:

referring to fig. 1 and 2, the ultra-wideband fluorescent quantum dot doped quartz amplifying fiber comprises a fiber core 1 and a cladding 2, wherein the fiber core 1 comprises an outer silica loose layer 1-1 and middle semiconductor quantum dot material layers 1-2 with different sizes and uniformly distributed; the core 1 is located in the middle of the cladding 2. The silicon dioxide loose layer 1-1 is high-purity silicon dioxide or is doped with a small amount of high-refractive-index GeO₂The silica material of (1). The semiconductor quantum dot material layer is used for depositing PbS quantum dots with different sizes and aluminum oxide Al by utilizing an ALD (atomic layer deposition) technology and an in-situ annealing technology₂O₃With germanium oxide GeO of increasing refractive index profile₂A material. By controlling the cycle period to be 50-500 periods, the annealing temperature to be 200-300 ℃, the annealing time to be 30min, the size of the semiconductor PbS quantum dots to be 3-10 nm and the doping concentration to be 1.5mol percent. Then, alumina and germanium oxide were deposited again, and the concentration was controlled to 3.0 mol%. The cladding 2 is made of a pure silica material having a lower refractive index than the core 1. And finally, MCVD high-temperature rod shrinkage is adopted to obtain an optical fiber preform, and the optical fiber preform is placed in a wire drawing tower for wire drawing to prepare the ultra-wideband fluorescent PbS quantum dot doped quartz amplification optical fiber. The optical fiber performance parameters are as follows: the diameter of the core 1 is 8 μm, the diameter of the cladding 2 is 126 μm, the difference between the refractive indexes of the core 1 and the cladding 2 is about 0.8%, and the absorption peak range of the optical fiber is 4001600nm, a fluorescence spectrum range of 600-1700 nm and a gain range of 1000-1650 nm.

Example 2:

the present embodiment is substantially the same as the first embodiment, except that the process parameters are different, and the structural parameters of the optical fiber are adjusted.

Referring to fig. 1 and 2, the ultra-wideband fluorescent quantum dot doped quartz amplifying fiber comprises a fiber core 1 and a cladding 2, wherein the fiber core 1 comprises an outer silica loose layer 1-1 and middle semiconductor quantum dot material layers 1-2 with different sizes and uniformly distributed; the core 1 is located in the middle of the cladding 2. The silicon dioxide loose layer 1-1 is high-purity silicon dioxide or is doped with a small amount of high-refractive-index GeO₂The silica material of (1). The semiconductor quantum dot material layer is used for depositing PbSe quantum dots with different sizes and aluminum oxide Al by utilizing an ALD (atomic layer deposition) technology and an in-situ annealing technology₂O₃With germanium oxide GeO of increasing refractive index profile₂A material. By controlling the cycle period to be 100-800 periods, the annealing temperature to be 180-350 ℃, the annealing time to be 20min, the size of the semiconductor PbSe quantum dot to be 5-30 nm and the doping concentration to be 1.5mol percent. Then, alumina and germanium oxide were deposited again, and the concentration was controlled to 3.5 mol%. The cladding 2 is made of a pure silica material having a lower refractive index than the core 1. And finally, MCVD high-temperature rod shrinkage is adopted to obtain an optical fiber preform, and the optical fiber preform is placed in a wire drawing tower for wire drawing to prepare the ultra-wideband fluorescent PbSe quantum dot doped quartz amplifying optical fiber. The optical fiber performance parameters are as follows: the diameter of the fiber core 1 is 10 mu m, the diameter of the cladding 2 is 130 mu m, the refractive index difference between the fiber core 1 and the cladding 2 is about 1.0%, the absorption peak range of the optical fiber is 300-1600 nm, the fluorescence spectrum range is 500-1800 nm, and the gain range is 800-1500 nm.

Example 3:

referring to fig. 1 and 2, the ultra-wideband fluorescent quantum dot doped silica amplifying fiber comprises a fiber core 1 and a cladding 2, wherein the fiber core 1 comprises an outer silica loose layer 1-1 and a middle uniformly distributed semiconductor quantum dot material layer 1-2 with different sizes; 1 bit of the fiber coreIn the middle of the cladding 2. The silicon dioxide loose layer 1-1 is high-purity silicon dioxide or is doped with a small amount of high-refractive-index GeO₂The silica material of (1). The semiconductor quantum dot material layer is used for depositing PbS/PbSe co-doped quantum dots with different sizes and alumina Al by utilizing an ALD technology and an in-situ annealing technology₂O₃With germanium oxide GeO of increasing refractive index profile₂A material. The method comprises the specific steps of firstly preparing multi-size PbS quantum dots by using an ALD technology and an in-situ annealing technology, wherein the annealing temperature is 190-300 ℃, the thickness is 50-100 nm, and the size of the PbS quantum dots is 5-15 nm; then preparing multi-size PbSe quantum dots by using an ALD technology and an in-situ annealing technology, wherein the thickness of the multi-size PbSe quantum dots is 80-200 nm, the annealing temperature is 200-400 ℃, the annealing time is 10min, and the size of the semiconductor PbS/PbSe quantum dots is adjusted to be controlled between 10-40 nm; then, alumina and germanium oxide were deposited, and the concentration was controlled to 5.0 mol%. The cladding 2 is made of a pure silica material having a lower refractive index than the core 1. And finally, MCVD high-temperature rod shrinkage is adopted to obtain an optical fiber preform, and the optical fiber preform is placed in a wire drawing tower for wire drawing to prepare the ultra-wideband fluorescent PbS/PbSe quantum dot codoped quartz amplifying optical fiber. The optical fiber performance parameters are as follows: the diameter of the fiber core 1 is 20 microns, the diameter of the cladding 2 is 150 microns, the refractive index difference between the fiber core 1 and the cladding 2 is about 2.0%, the absorption peak range of the optical fiber is 250-1600 nm, the fluorescence spectrum range is 400-2000 nm, and the gain range is 800-1700 nm.