139 results about "Erbium ions" patented technology

An optical fiber amplifier utilizing a phosphate glass optical fiber highly doped with rare-earth ions such as erbium to exhibit high gain per unit length, enabling the use of short fiber strands to achieve the needed gain in practical fiber optical communication networks. The high-gain phosphate optical glass fiber amplifiers are integrated onto substrates to form an integrated optics amplifier module. An optical pump such as a semiconductor laser of suitable wavelength is used to promote gain inversion of erbium ions and ultimately provide power amplification of a given input signal. Gain inversion is enhanced in the erbium doped phosphate glass fiber by co-doping with ytterbium. A phosphate fiber amplifier or an integrated optics amplifier module utilizing this power amplification can be combined with other components such as splitters, combiners, modulators, or arrayed waveguide gratings to form lossless or amplified components that do not suffer from insertion loss when added to an optical network. The fiber amplifier can be a single fiber or an array of fibers. Further, the phosphate glass fibers can be designed with a temperature coefficient of refractive index close to zero enabling proper mode performance as ambient temperatures or induced heating changes the temperature of the phosphate glass fiber. Large core 50-100 .mu.m fibers can be used for fiber amplifiers. The phosphate glass composition includes erbium concentrations of at least 1.5 weight percentage, preferably further including ytterbium at 1.5 weight percentage, or greater.

A device for harmonizing a laser beam path with an observation path for a target includes a laser that generates a laser beam; a first optical element that directs a first part of the laser beam toward the target along the laser beam path while directing a second part of the laser beam toward a conversion device; and a second optical element that directs a converted beam from the conversion device to a sensor that receives the converted beam and an image from the target. The conversion device includes a photoluminescent material that converts the second part of the laser beam into a converted radiation having a wavelength within a spectral band of the sensor, and an optical assembly that focuses the second part of the laser beam into the photoluminescent material and that collects at least a portion of the converted radiation to form the converted beam. The photoluminescent material can include photoluminescent ions such as erbium ions, or a semiconductor material such as indium arsenide. The photoluminescent material can include two materials, wherein the first material has a photoluminescence lifetime greater than a pulse duration of the pulsed laser beam, and the second material has an emission spectrum of photoluminescence covering at least a portion of a sensitivity spectral band of the sensor. The conversion device can also include a non-linear material that frequency converts the second part of the laser beam into an intermediary radiation having a wavelength shorter than the laser beam, and where the photoluminescent material converts the intermediary radiation into the converted radiation.

The invention relates to the production of light-amplifying optical material. Liquid reactant is atomized into droplets using a high velocity gas. The droplets are subsequently introduced into a flame. Reactants are oxidized in the flame and condensed by forming small particles. At least a fraction of said particles is collected and fused to form optical waveguide material, which is subsequently drawn to form an optical waveguide. According to the invention, the velocity of the atomizing gas stream is in the order of the velocity of sound. The high velocity enhances atomization and increases reaction rates in the flame. The residence times are reduced to such a degree that unwanted phase transformations in the produced particles are substantially minimized. Consequently, very homogeneous material is produced. Especially, in the production of erbium-doped silica, low percentage of clustered erbium ions is achieved.

An optically active fiber (30) is disclosed for making a fiber laser (18) or an amplifier (16) for optically pumping by a broad area laser diode for operation in the 1.5 micron band. This double-clad structured active fiber (30) has a core (34), doped with an optically excitable erbium ion having a quasi-three-level transition. The core (3) has a core refractive index and a core cross-sectional area. An inner cladding (32) surrounds the core (34). The inner cladding (32) has an inner cladding refractive index less than the core refractive index, an inner cladding cross-sectional area between 2 and 25 times greater than that of the core cross-sectional area, and an aspect ratio greater than 1.5:1. An outer cladding (36) surrounds the inner cladding (32) and has an outer cladding refractive index less than the inner cladding refractive index.

The invention relates to erbium-doped transparent glass ceramic containing nanocrystalline barium yttrium fluoride and the preparation method thereof, which relates to the field of luminescent material. The components of glass ceramic are (mole ratio): 40SiO2-25Al2O3-xBaCO3-10YF3-yBaF2-zErF3 (x=5-20, z=0.1-3.0, y=25-x-z). The invention is prepared by melt-spinning technique and adopts SiO2, Al2O3, BaCO3, YF3, BaF2 and ErF3 powder as raw materials, and the raw materials are well mixed, heated to 1300-1600 DEG C and the temperature is preserved for 1-4 hours, and then melting fluid is prepared into vitreous body; the vitreous body is annealed to relieve internal stress, continues to be heated to 650-800 DEG C, the temperature is preserved for 1-10 hours, and the obtained nanocrystalline has extremely high solid solubility of erbium ion. With the infrared excitation, the up-conversion emission intensity of the glass ceramic is greatly improved by adjusting heat treatment temperature.

The invention discloses an anti-radiation wide spectrum fiber light source. 980nm pump light can be coupled in an Er-doped fiber by a wavelength division multiplexer (WDM), and mixed light is output after the light is amplified through spontaneous emission (ASE) of erbium ions; the mixed light can generate reflected light after being processed by a second WDM and a reflecting mirror; the remnant 980nm pump light output from the second WDM can be converted to a voltage signal by a 980nm monitoring detector, and the voltage signal can act on a 980nm pump light source after being processed by a microprocessor and a digital constant current source; and an automatic temperature control circuit can ensure the 980nm pump light source to work at the temperature of 25 DEG C. The wide spectrum fiber light source provided by the invention utilizes the electrical signal output by the 980nm monitoring detector as a basis of feedback regulation and regulates drive current to control the stability of power and average wavelength of the output ASE light by using the negative feedback closed loop control principle, and thus the anti-radiation problem of the wide spectrum fiber light source can be well solved by using an active protective technology under the condition of not increasing the weight of the light source system.

The present invention relates to a method for making erbium doped high-silica infrared luminescent glass. Said method includes the following steps: (1), selecting high-silica porous glass, SiO2 content in said glass is 95-98 wt%; (2), preparing solution containing erbium ion, the erbium ion concentration range is 0.02-0.42 mole / L; (3), soaking the high-silica porous glass in the solution containing erbium ion to form high-silica porous glass containing erbium ion; and (4), drying and solid-phase sintering in high-temperature furnace at 1050-1200deg.C so as to obtain the invented product. Said glass can produce infrared red light nearby frequency range of 1.53 micrometer, and can produce laser light of 1.54 micrometer in laser resonance cavity.

The invention relates to intermediate infrared anhydrous fluorine tellurate laser glass and a preparation method thereof. The intermediate infrared anhydrous fluorine tellurate laser glass is prepared from 50-85 mol percent of TeO2, 5-45 mol percent of ZnF2 or BaF2, 0-20 mol percent of ZnO, 0-20 mol percent of sodium ion compound or potassium ion compound and 0.1-2 mass percent of erbium ion compound. The invention provides the intermediate infrared anhydrous fluorine tellurate laser glass which can generate strong intermediate infrared luminescence and is expected to be applied to medicine, bioindustry and economic construction, as well as a preparation method of the intermediate infrared anhydrous fluorine tellurate laser glass.

The invention relates to a chromium and praseodymium sensitized ions co-doped gadolinium gallium garnet novel laser crystal activated by erbium ions. The crystal material has a chemical formula of Cr:Er:Pr:Gd3Ga5O12. Gd2O3, Ga2O3, Er2O3, Cr2O3 and Pr2O3 of 4N are used as raw materials which are subjected to high-temperature solid-phase reaction to obtain Cr:Er:Pr:Gd3Ga5O12 raw material and used to grow the crystal by a crystal pulling method under the condition of nitrogen atmosphere. The material is used for achieving tunable laser output of 2,600 to 3,000nm waveband.

Ion imprinted polymer materials are synthesized containing metal ion recognition sites. These particles are synthesized by copolymerizing with functional and cross linking monomers in presence of at least one imprint metal ion in the form of ternary complex. The polymerization was carried out by □-irradiation (in the absence of initiator) or photochemical and thermal polymerization (in presence of initiator, AIBN). These materials were ground and sieved after drying to obtain erbium ion imprinted polymer particles. The erbium ion was removed from the polymer particles by leaching with mineral acid which leaves cavities / binding sites in the polymer particles. The resultant polymer particles can be used as solid phase extractants for selective enrichment of erbium ions from dilute aqueous solutions.

The invention discloses a pulse laser light source capable of generating a nanosecond-level high-power narrow-pulse light and providing a light peak power of 100 W. The pulse laser light source is characterized by comprising a pump laser, a pump laser constant-current driving module, a distributed feedback (DFB) laser, a pulse signal generation module, a narrow-pulse driving module, an optical wavelength division multiplexer (WDM) and erbium-doped fiber, wherein the optical WDM is connected with output ends of the DFB laser and the pump laser and one end of the erbium-doped fiber and used for coupling narrow-pulse lights generated by light seed sources (the DFB laser) of different wavelengths with a pump light into the erbium-doped fiber; and the erbium-doped fiber is used for exciting erbium ions to a high-energy-level (three-energy-level) system under the action of a pump laser when a DFB laser and the pump laser simultaneously enter the erbium-doped fiber, then quickly decaying the erbium ions to a metastable-state-energy-level system, and transmitting a photon corresponding to the DFB laser when the erbium ions are returned to a ground-state-energy-level system under the action of the DFB laser to make the DFB laser amplified. The pulse laser light source meets requirements on development of a distributed optical fiber temperature sensing system.

The invention discloses a preparation method of a rare earth up-conversion nanometer diagnosis and treatment agent. The preparation method comprises the following steps: combining Er3+ doped up-conversion nanometer particles NaYF4 with an indocyanine green dye (ICG) molecule to form an ICG-LNPs compound; and modifying the ICG-LNPs compound by adopting modification of coupling polyethylene glycol so as to obtain DSPE-mPEG-ICG-LNPs. The invention also discloses the rare earth up-conversion nanometer diagnosis and treatment agent. By adopting the advantage that the rare earth up-conversion nanometer material NaYF4:Er is emitted in a near-infrared second area, the ICG molecule is coupled with the nanometer material, the ICG can strengthen 1520 nm of Er3+ to emit light, and the technical problem that an up-conversion nanometer material doped trivalent rare earth erbium ion (Er3+) fluoride nanocrystal is low in luminous efficiency in the prior art is solved.

A method of modeling erbium doped fiber ("EDF") for use in erbium doped fiber amplifiers ("EDFA"). The EDF has a length and a fractional population density of erbium ions in an excited state. Since the EDF supports N channels, the power propagation along the EDF is characterized by N+1 differential equations as a function of the direction of propagation, z, of the channels along the length l of the EDF and the time t. By applying an average inversion model to a spatially averaged inversion level of the erbium ions in the fiber, the N+1 partial differential equations are reduced to a single ordinary differential equation. This allows an analytical solution at the boundary and initial conditions of the fiber so that an expression for the power of the signal propagating along the fiber can be obtained. With this expression, the single equation can be solved analytically for the inversion level at any point along the EDF.

A ytterbium-erbium-ion-double-intermingled gadolinium-natrium molybdate laser crystal and its preparing method and its use, relate to artificial lens field, in particular relate to a laser crystal Ytterbium-erbium-ion-double-intermingled gadolinium-natrium molybdate (Yb3+ / Er3+:NaGd(MoO4)2) and its preparing method and its use. Yb3+ / Er3+:NaGd(MoO4)2 crystal having high quality and bigger size is produced by the pulling method (Czochralski method) at 1173 DEG C, at the crystal rotational speed of 10-30 turns / minute, under the drawing speed of 0.5-2 mm / hour. The crystal is a novel laser crystal, and can produce the laser output of about 550 nm and 1500 nm wavelengths.

The invention provides an erbium ion doped intermediate infrared luminous fluorine tellurate glass. In terms of mol percentage, the glass comprises the following components by mole percent: 43-53 % of ZrF4, 18-22 % of CaF2, 3-5 % of YF3, 2-4 % of AlF3, 18-22 % of NaF, 0-5 % of TeO2, 0-5 % of GeO2, 0-5 % of Bi2O3 and 2-8 % of ErF3. The glass is prepared by using a covered platinum crucible and a silicon carbide rod electric furnace melting method. According to the invention, after heavy metal oxide is introduced, a fluoride glass is still transparent without crystallization, the infrared transmission rate of the glass is 85 % near intermediate infrared 2.7 microns, the heat stability of the glass is improved and the chemical stability of the glass is also improved; under laser diode pumping with wavelength of 980 nm, obviously enhanced intermediate infrared 2.7 microns fluorescence can be obtained; and the erbium ion doped intermediate infrared luminous fluorine tellurate glass provided by the invention is suitable for preparing and using erbium ion doped special glass and optical fiber materials which are luminous at intermediate infrared wave band of 2.7 microns.

The invention relates to a preparation method of erbium ion-doped calcium fluoride laser transparent ceramic, which comprises synthesis of raw material powder, sintering and post treatment of laser transparent ceramic and other steps, wherein sintering powder is nano powder obtained by a direct chemical reaction coprecipitation method, and the grain size of the nano powder is 15-60nm; the mol content of rare earth ions Er<3+> is 1-20%; by using the discharge plasma sintering technology, the density of the prepared laser ceramic is more than 99.6%, and the grain size of the laser ceramic is 1-10 mu m; and the ceramic has a maximum transmittance of about 87% in the visible light and near infrared bands, has strong absorption peaks at 377nm, 519nm and 652nm, has wide absorption bands at 804nm, 974nm and 1526nm, and can be used as infrared and upconversion laser working gain media. The invention has the advantages of simple nano powder preparation process, low ceramic sintering temperature, short ceramic sintering time and the like.

An optically active fiber(30) is disclosed for making a fiber laser(18) or an amplifier(16) for optically pumping by a broad area laser diode for operation in the 1.5 micron band. This double-clad structured active fiber(30) has a core(34), doped with an optically excitable erbium ion having a quasi-three-level transition. The core(34) has a core refractive index and a core cross-sectional area. An inner cladding(32) surrounds the core(34). The inner cladding(32) has an inner cladding refractive index less than the core refractive index, an inner cladding cross-sectional area between 2 and 25 times greater than that of the core cross-sectional area, and an aspect ratio greater than 1.5:1. An outer cladding(36) surrounds the inner cladding(32) and has an outer cladding refractive index less than the inner cladding refractive index.

The invention discloses a few-mode erbium-doped optical fiber. A fiber core of the few-mode erbium-doped optical fiber comprises a first layer, a second layer and a third layer from inside to outside,the first layer is round, the second layer is in a first annular shape, the third layer is in a second annular shape, and the refractive index of the second layer is larger than the refractive indexof the first layer and larger than the refractive index of the third layer. The erbium ion doping concentration of the second layer is less than the erbium ion doping concentration of the first layerand less than the erbium ion doping concentration of the third layer. According to the scheme provided by the invention, gain flatness among transmission modes can be realized only through single-fundamental-mode pumping, and weak coupling transmission of a to-be-amplified signal in the few-mode erbium-doped fiber is realized at the same time.

A short laser cavity (up to 30 cm in length) comprising a free-space tunable MEMS Fabry-Perot filter, a collimating lens and a section of erbium-doped phosphate gain fiber (2-25 cm) is formed between a pair of broadband reflectors. The cavity is optically pumped to excite the erbium ions and provide gain, which establishes an initial longitudinal mode structure that spans the C-band with a mode spacing of at least 0.3 GHz and a roundtrip unsaturated gain of at least 8 dB over the tuning range. A controller tunes the MEMS filter, which has a filter function whose spectral width is at most ten and preferably less than four times the longitudinal mode spacing, to align its transmission maxima to one of a plurality of discrete output wavelengths that span the C-band. A thermal control element adjusts the longitudinal mode structure to align a single mode with the transmission maxima of the filter. Because the spectral width of the filter function is narrow, laser emission will be limited to a single longitudinal mode.

The invention relates to the production of light-amplifying optical material. Liquid reactant (10) is atomized into droplets (15) using a high velocity gas (20) . The droplets (15) are subsequently introduced into a flame (100) . Reactants (10, 30) are oxidized in the flame (100) and condensed by forming small particles (50) . At least a fraction of said particles (50) is collected and fused to form optical waveguide material, which is subsequently drawn to form an optical waveguide (750) . According to the invention, the velocity of the atomizing gas (20) stream is in the range of 0.3 to 1.5 times the velocity of sound. The high velocity enhances atomization and increases reaction rates in the flame (100) . The residence times are reduced to such a degree that unwanted phase transformations in the produced particles (50) are substantially minimized. Consequently, very homogeneous material is produced. Especially, in the production of erbium-doped silica, low percentage of clustered erbium ions is achieved.

The invention is applicable to the technical field of a lithium battery, and provides an aluminium and erbium coated high-nickel lithium-ion cathode material and a preparation method thereof. The method comprises the steps of: preparing aluminium and erbium coating liquid; dispersing a lithium-ion cathode material into water, regulating pH into an alkaline state, in a stirring state, firstly adding erbium coating liquid and then adding the aluminium coating liquid, and continuously stirring to obtain suspension; and filtering the suspension, and drying, roasting and sieving precipitates to obtain the aluminium and erbium coated lithium-ion cathode material. According to the method provided by the invention, metal aluminium and erbium ions can be well dissolved in solution and are uniformlycoated on the surface of the cathode material so as to fulfill the aim of integrating washing with coating. Residual alkali of the high-nickel lithium-ion cathode material is efficiently reduced in the aspect of physical and chemical performance, reaction of the cathode material and electrolyte is inhibited, normal temperature and high temperature cycle performance of the high-nickel cathode material are improved, and flatulence is reduced.

The invention provides a dual-wavelength pumped erbium-doped fluoride fiber laser and a laser generating method. The fiber laser comprises a first pump laser, a second pump laser, a beam combiner, a first fiber Bragg grating, and a double-cladding erbium-doped fluoride fiber and an AlF3 end cap. The first pump light is coupled into the inner cladding of the double-cladding erbium-doped fluoride fiber, 2.8 mum laser radiation is formed between an erbium ion energy level <4>I<11 / 2> and an energy level <4>I<13 / 2>, the second pump light is coupled to the fiber core of the double-cladding erbium-doped fluoride fiber, excited erbium ions in the energy level <4>I<13 / 2> are pumped to an energy level <4>I<19 / 2>, heat rise of a laser caused by generation of 1.6 mum between energy levels <4>I<13 / 2> and <4>I<15 / 2> is suppressed while the number of erbium ions in the energy level <4>I<11 / 2> is increased, and the slope efficiency and the output power of the 2.8 mum laser radiation of the fiber laserare remarkably increased.

The invention discloses a nanometer silicon concentric micro ring core er-doped laser device and a manufacturing method of the nanometer silicon concentric micro ring core er-doped laser device. The laser device comprises a silicon substrate and a micro disc, the micro disc is connected with the silicon substrate through a micro disc supporting column formed on the silicon substrate and comprises a peripheral micro disc body and an inside micro disc body which are arranged coaxially, the inside micro disc body is directly formed on the peripheral micro disc body, the edge of the peripheral micro disc body is fused to form a micro ring core structure, the peripheral micro disc body is a silicon oxide thin film layer with the er-doped edge, and the inside micro disc body is a thin film layer with a silicon nano quantum dot structure. According to the nanometer silicon concentric micro ring core er-doped laser device, the good light gain characteristic of nanometer silicon is utilized, efficient light pumping is carried out on erbium ions, the spontaneous radiation probability is improved, meanwhile, absorption of carriers in the nanometer silicon or other loss factors cannot be introduced into the gain laser mode of the micro ring core edge erbium ions, and therefore high-quality communication waveband micro-cavity mode emitted light can be obtained.

The invention provides an erbium ion activated 3-micron wave-band gallate laser crystal and its preparation method. The chemical formula of the crystal is Erx:AR(1-x)Ga3O7, wherein A is at least one of Ca, Sr and Ba; R is at least one of Y, La, Gd and Lu; and the value of x changes from 0 to 1 according to laser operation requirements. The crystal can be pumped by diode laser to output 3-micron wave-band laser. The crystal can grow by a czochralski method. The preparation method requires a simple process and is easy to operate.

The invention discloses a vanadate up-conversion light-emitting material activated by erbium ions Er<3+> and a preparation method thereof. The molecular formula of the vanadate up-conversion light-emitting material is Na2R1-xErxMg2V3O12, wherein R is one or more of rare earth ions Gd<3+>, La<3+>, Y<3+> and Dy<3+>; x is the mol percentage of doped Er<3+>; and x is more than or equal to 0.001 and is less than or equal to 1. The preparation method comprises the following steps of: weighing raw materials according to a ratio and uniformly milling; carrying out primary pre-burning sintering at 300-950 DEG C; cooling and then uniformly milling; carrying out secondary sintering on the mixed material at 950-1300 DEG C; after uniformly milling, sintering the mixed material at 1300-1500 DEG C; and cooling and milling so as to obtain the vanadate up-conversion light-emitting material. The vanadate up-conversion light-emitting material has the advantages of good chemical stability and heat stability, and high brightness and high color purity under an infrared laser light source; and the vanadate up-conversion light-emitting material has a wide prospect in application fields of vanadate up-conversion fluorescent powder, high-density light storage, fluorescent probes, high-resolution display and the like.

The invention provides an erbium ion activated 1.55-micron wave-band gallate laser crystal and its preparation method. The general chemical formula of the crystal is Cex:Yby:Erz:AR(1-x-y-z)Ga3O7, wherein Er is activated ion, Yb is sensitized ion, Ce is de-excitation ion, A is at least one of Ca, Sr and Ba, R is at least one of Y, La, Gd and Lu, the values of x, y and z change from 0 to 1 according to laser operation requirements, and x+y+z is less than or equal to 1. The crystal belongs to a tetragonal crystal system and space group is as defined in the specification. The crystal can be used as a gain medium of a diode laser-pumped 1.55-micron wave-band laser. The crystal can grow by a czochralski method. The preparation method requires a simple process and is easy to operate.

The invention discloses a manufacturing method for a waveguide amplifier with an erbium-doped tantalum oxide ridge structure. The amplifier made by the method comprises a substrate, a silica lower cladding, an erbium-doped lithium niobate film layer, a silica buffer layer, an erbium-doped tantalum oxide ridge waveguide structure, and a silica upper cladding. A silicon substrate lithium niobate film is used as a chip. The erbium-doped tantalum oxide whose refractive index is close to the refractive index of the lithium niobate is used as the ridge structure. In a communication band, through amplification effect of erbium ions, optical loss caused by processes of optical transmission and modulation can be made up. Compared with a dry etching technology, the manufactured ridge structure is low in process cost, and high in finished product rate, and stability of a device is improved. The manufacturing method is advantaged by simple manufacturing process, small device dimensions, small bending radius, and good stability.

The invention discloses an Er-doped fluorophosphate tellurite glass fiber for fabricating a high-power wideband fiber amplifier. The Er-doped fluorophosphate tellurite glass fiber comprises a fiber core and a fiber coating layer, wherein the fiber core comprises Er-doped fluorophosphate tellurite glass, the Er-doped fluorophosphate tellurite glass comprises the following constituents based on percent by mole: 40-90% of TeO2, 0-60% of BaF2, 0-14.99% of Y2O3, 0.01-10% of Er2O3 and 0-10% of Yb2O3, the fiber coating layer comprises fluorophosphate tellurite, and the fluorophosphate tellurite comprises the following constituents based on percent by mole: 40-90% of TeO2, 0-60% of BaF2 and 0-15% of Y2O3. The matrix glass is founded in a glove box with nitrogen protection, so that low hydroxyl content in the prepared glass sample is ensured, and an optical fiber is prepared by a rod-in-tube method. The fluorophosphate tellurite glass used in the invention has relatively high deliquescence-resistant capability, high erbium ion emission bandwidth and relatively high glass conversion temperature, so that the optical fiber can be used for fabricating the high-power wideband fiber amplifier.

The invention discloses a method for preparing a silicon-based light emitting diode (LED). The method comprises the following steps: S1, preparing erbium silicon oxygen sol; S2, coating the erbium silicon oxygen sol on a p-type doped silicon substrate, and preparing an erbium silicate inorganic compound and silicon-rich silicon oxide mixture film serving as an intrinsic layer; and S3, depositing a layer of phosphorus-doped silicon material on the p-type doped silicon substrate to make an n-type electrode and form the silicon-based LED. By preparing an erbium silicate inorganic compound and silicon-rich silicon oxide mixture film serving as the intrinsic layer of the silicon-based LED, the invention increases the concentration of erbium ions in the erbium silicate inorganic compound by 1 to 2 orders of magnitude, and electroluminescence can be realized through the efficient energy transfer between nano silicon and erbium ions in the silicon-rich silicon oxide so as to realize electroluminescence of the LED at a strong communication wave band of 1.53 mu m.

The invention provides a single grating high gain flatness L-band erbium doped fiber amplifier, belongs to the technical field of optical communication and aims to solve the problems that according to an erbium doped fiber amplifier of an existing optical fiber annular mirror structure, the gain enhancing amplitude is uneven, and the gain flatness is poor. A tunable laser emits the L-band light entering a first wavelength division multiplexer via a first insulator and a first pumping source to reach a first doped fiber, the first doped fiber emits C-band amplified spontaneous emission light, the L-band light, the C-band amplified spontaneous emission light and the light emitted by the second pumping source enter a second doped fiber via a second wavelength division multiplexer and an optical fiber grating, and the L-band light amplification is implemented; the amplified L-band light and the residual C-band amplified spontaneous emission light reach a second insulator; the L-band signals pass, the residual C-band amplified spontaneous emission light is reflected to the second doped fiber through the end face of the second insulator, secondary reflection is formed until the residual C-band amplified spontaneous emission light reaches the optical fiber grating, the erbium ions of the second doped fiber are excited once more, and the secondary pumping of the L-band signal light is implemented. The amplifier is applied to optical communication and sensing systems.