Multistage tandem type 1064nm wave band high power ASE light source
Technical field
The present invention relates to the applied light sources in field such as optical fiber communication, Fibre Optical Sensor and fiber-optic probe, especially a kind of 1064nm wave band high power output ASE optical fiber source of multistage tandem type structure.
Background technology
1064nm wave band ASE light source is to utilize rear-earth-doped ytterbium ion (Yb
3+) optical fiber amplified spontaneous emission (Amplified Spontaneous Emission; ASE) wideband light source of principles; Because have wide emission spectra, higher output power (about tens mW of common ASE light source output power), stability is high and be easy to and the effective advantage such as coupling of fibre system, becomes the optimal selection of desirable ASE light source.
The type ASE light source adopts multimode cladding pumping technology, with near the rear-earth-doped ytterbium ion (Yb of semiconductor pump laser pumping 800 ~ 1100nm
3+) active doubly clad optical fiber (YDF), can produce amplified spontaneous emission (ASE) light of 1000 ~ 1150nm wave band output.Because light-emitting diode (LED), super-radiance light emitting diode (SLD) or traditional ASE light source all have the shortcoming of low power output; Their extensive uses in communication system have seriously been limited; Therefore, especially very urgent demand has been proposed high power output ASE light source.
For unistage type structure ASE light source; No matter take forward direction, back to or the two directional pump mode, still one way or round trip output is exported in order to obtain high power ASE light; Correspondingly will use very strong pump power that YDF is carried out pumping, this can bring some problems that can't overcome.The one, the YDF gain is very high, and relying on merely increases pumping light power, is very easy to self-oscillation and forms laser output, has produced not ASE light.The 2nd, pump light is after accomplishing pumping process, and the relative residual pump energy can be comparatively considerable, and residual clad pumping optical can cause damage to optical fiber and optical device, and causes that power output is unstable.The 3rd, high power ASE light source output direction generally connects 1064nm high power light isolator; Guarantee the one-way transmission and the reflection of inhibition light of light; But its isolation index and bandwidth of operation are limited; Can the isolation of its centre wavelength also only about 30dB, effectively guarantee the inhibition ability to reflection of fiber end face light or light feedback? The 4th, doubly clad optical fiber welding contact is the coating processes problem again, and general bundling device exports passive doubly clad optical fiber and active doubly clad optical fiber needs welding; Contact after stripping covered needs special expensive coating machine apply protection again; Coating processes quality quality directly can influence pumping coupling efficiency (poor, the unmatched contact of uniformity consistency applies effect and causes pump light to be revealed), does not advance active doubly clad optical fiber inner cladding at least about 30% pump light, also influences the mechanical fiber optic performance.
Summary of the invention
The objective of the invention is to solve the problem that above-mentioned ASE light source exists, propose multistage tandem type 1064nm wave band high power ASE light source.
The present invention adopts multistage tandem type structure, adopts multimode cladding pumping technology, with near the semiconductor pump laser pumping wavelength 800 ~ 1100nm, the highly doped ytterbium ion (Yb of covering pumping
3+) active doubly clad optical fiber (YDF), pump light is coupled into the YDF inner cladding through bundling device, when passing through the YDF fibre core, and Yb
3+The ionic absorption pump light transits to high level from ground state level under its effect; Along with pump power strengthens; The spontaneous radiation population increases gradually and realizes reversing; Single particle independently spontaneous radiation gradually becomes the harmonious stimulated radiation of a plurality of particles, promptly produces amplified spontaneous emission (ASE) light of higher-wattage output 1000 ~ 1150nm wave band.
The object of the invention is realized through following technical scheme:
Multistage tandem type 1064nm wave band high power ASE light source; It comprises n section cascade structure; Each section cascade structure includes active bundling device, active doubly clad optical fiber (YDF) and the optical isolator that connects in order, and the optical isolator output of i section cascade structure links to each other with the active bundling device input of i+1 section cascade structure; I section cascade structure comprises the active bundling device of i level, the active doubly clad optical fiber of i section (YDF) and i optical isolator, and i is the sequence number of cascade structure place section; In the n section cascade structure, be connected with a cladding mode stripper between active doubly clad optical fiber and the optical isolator; The output of n optical isolator is said ASE light source output, and the active bundling device input of the first order links to each other with n+1 optical isolator input, and n+1 optical isolator output links to each other with the functional form multimode fiber; Said active doubly clad optical fiber is a Yb dosed optical fiber.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source; Also comprise semiconductor pump laser; Adopt multi-mode coupler that the power output of semiconductor pump laser is divided into the n part; The output tail optical fiber of this n part pump light is linked to each other with the pumping input optical fibre of the active bundling device of n level respectively, be respectively the active doubly clad optical fiber of n section pump energy is provided, n part pumping light power is the highest.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source; The active bundling device of each grade all comprises passive doubly clad optical fiber and pumping input optical fibre separately; Passive doubly clad optical fiber with the active doubly clad optical fiber welding of one-level, pumping input optical fibre fused biconical taper is coupled in above the active doubly clad optical fiber inner cladding of one-level.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source; Said semiconductor pump laser output wavelength is 800~1000nm, and power output is greater than 1W, and output tail optical fiber core diameter is 105~200 μ m; Cladding diameter is 125~220 μ m, and numerical aperture is 0.12~0.22.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source, said active doubly clad optical fiber core diameter is 7~20 μ m, and the inner cladding diameter is 125~200 μ m, and the fibre core numerical aperture is 0.08~0.20; Said active doubly clad optical fiber length is 3~15 meters.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source, said functional form multimode fiber (16) is for having the multimode fiber that filters with anti-reflection, and its fiber end face grinds and the coated with antireflection film; It is 10~100 μ m that awl to awl district diameter is drawn in the multimode fiber middle part, will bore the district and apply high refractive index UV glue and encapsulation; Said multimode fiber core diameter is 50~200 μ m, and cladding diameter is 125~220 μ m, and numerical aperture is 0.12~0.22.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source, said cladding mode stripper (13) carries out welding by active doubly clad optical fiber one end and passive single cladded fiber one end and constitutes, and the naked fine zone of contact is coated with high refractive index UV glue.
In the above-mentioned multistage tandem type 1064nm wave band high power ASE light source, said 2≤n≤7.
Said semiconductor pump laser power output is divided into the n part that power equates or do not wait by a certain percentage, the reasonable distribution that ensures pump powers at different levels with make full use of, n part pump power is the highest, with as the n level---power amplifier level pumping energy usefulness.
The present invention has following main advantage compared with prior art:
the present invention adopts multi-stage cascade formula structure to suppress laser and produces; Each grade forward direction ASE light is amplified as the next stage flashlight, progressively produce the output of high power ASE light.Avoid in the single step arrangement YDF gain too high, relying on merely increases pumping light power, is very easy to self-oscillatory shortcoming.
Power output with semiconductor pump laser among
the present invention is divided into the n part by a certain percentage; Reasonable distribution with make full use of pump power n section YDF carried out the segmentation pumping, reduced the use cost of semiconductor pump laser effectively.
the present invention adopts active bundling device; Directly pumping input optical fibre fused biconical taper is coupled in above the active doubly clad optical fiber inner cladding; Simplify technology; Avoided the passive mode in traditional bundling device technology, promptly its output is passive doubly clad optical fiber, links to each other with active doubly clad optical fiber welding then; Contact after stripping covered need carry out loaded down with trivial details coating operation again, and coating processes is difficult to grasp.
⑷ the present invention adopts special effective end face reflection braking measure; Be that one section of non-output welding has the functional form multimode fiber that filters with anti-reflection; Not only suppress the reflection of fiber end face light; And filtering do not have purposes ASE light, reduces fiber end face light injury effect, can increase substantially ASE power output level.
⑸ output direction of the present invention inserts a cladding mode stripper, utilizes joining zone high refractive index UV glue to form " oppositely " waveguiding structure, and in conjunction with the mode of " snakelike " groove curved fiber, the remaining cladding pumping light energy of filtering is avoided its damage effect effectively.
⑹ the present invention realizes having the above power output ASE light up to 1W, covers 1030 ~ 1090nm wave band, and the spectrum flatness is better, and Output optical power has good stability.
Description of drawings
Fig. 1 is the active bundling device structural representation of multistage tandem type 1064nm wave band high power ASE light source.
Fig. 2 is active bundling device structural representation.
Fig. 3 is a pump laser splitting ratio illustration intention.
Fig. 4 is a functional form multimode fiber structural representation.
Fig. 5 is a cladding mode stripper structural representation.
Fig. 6 is the ASE spectrogram that the embodiment of the invention is exported.
Embodiment
Enforcement example and accompanying drawing below in conjunction with concrete are further described explaination to the present invention, but are not limited to this execution mode.
As shown in Figure 1; Multistage tandem type 1064nm wave band high power ASE light source; It comprises n section cascade structure; Each section cascade structure includes active bundling device (1,5,9), active doubly clad optical fiber (2,6,10) and the optical isolator (4,8,12) that connects in order, and the optical isolator output of first section cascade structure links to each other with the active bundling device input of second section cascade structure; First section cascade structure comprises the active bundling device of the first order 1, first section active doubly clad optical fiber 2 and first optical isolator 4; In the n section cascade structure, be connected with a cladding mode stripper 13 between the active doubly clad optical fiber 10 of n section and n optical isolator 12; The active bundling device input of the first order links to each other with n+1 optical isolator 14 inputs, and n+1 optical isolator 14 outputs link to each other with functional form multimode fiber 16.
ASE light source light path device has the tertiary structure cascade in the present embodiment; By active bundling device (1,5,9); Active doubly clad optical fiber (YDF) (2,6,10); Optical isolator (4,8,12,14), cladding mode stripper 13, functional form multimode fiber 16, semiconductor pump laser 17 are formed.Active bundling device 1 output of the first order directly is connected with first section active doubly clad optical fiber 2; First section active doubly clad optical fiber 2 other end links to each other with first optical isolator 4 inputs, and first optical isolator 4 outputs link to each other with active bundling device 5 inputs in the second level; Active bundling device 5 outputs in the second level directly are connected with second section active doubly clad optical fiber (YDF) 6; Second section active doubly clad optical fiber 6 other end links to each other with second optical isolator 8 input; Second optical isolator 8 output links to each other with the active bundling device input of the third level; The active bundling device output of the third level directly is connected with the 3rd section active doubly clad optical fiber; The 3rd section active doubly clad optical fiber other end links to each other with cladding mode stripper 13 inputs, and cladding mode stripper 13 outputs link to each other with the 3rd optical isolator 12 inputs, and the 3rd optical isolator output is as ASE light source output.Active bundling device 1 input of the first order links to each other with the 4th optical isolator input, and the 4th optical isolator output links to each other with functional form multimode fiber 16.The YDF core diameter is 10.0 μ m in the present embodiment, and the inner cladding diameter is 127.5 μ m (being shaped as octagon), and the fibre core numerical aperture is 0.08.Three sections YDF that choose the above-mentioned type use length to be about 6 meters, 4 meters, 7 meters respectively.Final output ASE spectrum spectrum shape depends on first order output ASE spectrum situation, and first order selection YDF uses 6 meters of length slightly long, as first order working media, guarantees that the smooth ASE light of generation spectrum spectrum shape gets into next stage again and amplifies.
As further preferred embodiment, semiconductor pump laser 17 in the present embodiment.Progression n≤7 of said multistage cascade structure, said YDF core diameter are 7~20 μ m, and the inner cladding diameter is 125~200 μ m, and inner cladding is shaped as abnormal shape (like hexagon, octagon, D shape etc.), and the fibre core numerical aperture is 0.08~0.20.It is 4~12 meters that said first section YDF uses length, second section YDF ... It is 3~15 meters that n section YDF uses length, YDF to 800~1000nm pump light absorption coefficient greater than 0.5dB/m.
The only active bundling device of said n is based on the fused biconical taper process drawing; Its type is (m+1) * 1; M (pump ports number) >=1 (like (1+1) * 1, (2+1) * 1, (6+1) * 1 etc.); The passive doubly clad optical fiber core diameter of the input of active bundling device is 7~20 μ m, and the inner cladding diameter is 125~200 μ m.The pumping input optical fibre is a multimode fiber, and its core diameter is 105~200 μ m, and cladding diameter is 125~220 μ m, and numerical aperture is 0.12~0.22.Said semiconductor pump laser output wavelength is 800~1000nm, and power output is greater than 1W, and the output tail optical fiber is a multimode fiber, and its core diameter is 105~200 μ m, and cladding diameter is 125~220 μ m, and numerical aperture is 0.12~0.22.
As shown in Figure 2, active bundling device 1 used in the present invention is made up of with the active doubly clad optical fiber 2 of output the passive doubly clad optical fiber of input 15, pumping input optical fibre 3.At first two pumping input optical fibres 3 are shelled cover, after the clean, separately to the about 25 μ m of its prestretching to coupled zone diameter; Then with active doubly clad optical fiber 2 one ends and the 15 1 end weldings of passive doubly clad optical fiber, in direction, from the about 15mm of joint position fiber stripping near active doubly clad optical fiber 2; With the coupled zone of two pumping input optical fibres 3 behind the prestretching, the fused biconical taper operation is carried out at the above-mentioned fiber stripping position that is close to active doubly clad optical fiber, draws out the active bundling device in (2+1) * 1 at last.YDF 2 optical parametrics are core diameter 10.0 μ m among the embodiment, inner cladding diameter 127.5 μ m (being shaped as octagon), and the fibre core numerical aperture is 0.08.The passive doubly clad optical fiber 15 of the input of active bundling device, its optical parametric are core diameter 10.0 μ m, inner cladding diameter 125.0 μ m, and the fibre core numerical aperture is 0.08.Active bundling device pumping input optical fibre 3 is multimode fiber 105/125 0.22NA, and its core diameter is 105 μ m, and cladding diameter is 125 μ m, and numerical aperture is 0.22.
As shown in Figure 3; Semiconductor pump laser 17 in the present embodiment; Carry out beam split with multi-mode coupler; By a certain percentage its output pump power is divided into three parts that 15%, 25%, 60% power does not wait, the reasonable distribution that ensures pump powers at different levels with make full use of, avoid increasing that pump power is too drastic causes the self-oscillation problem and produce laser output; Three parts of pump light output tail optical fibers are linked to each other with the pumping input optical fibre 3,7,11 of three bundling devices respectively, be respectively three sections YDF 2,6,10 the pumping pumping energy is provided.Pump laser 17 parameters are wavelength 915nm in the present embodiment, and power output 10W is adjustable, and the output tail optical fiber is multimode fiber 105/125 0.22NA.Adopt above-mentioned multi-stage cascade structure to suppress generation of Laser, guarantee the output of high power ASE light.
Functional form multimode fiber 16 used in the present invention has the function that filters with anti-reflection, and the one of which end penetrates in the ceramic insertion core and injecting glue is fixed, and fiber end face is ground to form 8 ° of inclinations angle, and be coated with antireflective coating.Multimode fiber middle part stripping covered draw awl to handle, till awl district diameter 10~100 μ m, its awl district is applied high refractive index UV glue and is packaged in the fluting aluminium block.Said multimode fiber core diameter is 50~200 μ m, and cladding diameter is 125~220 μ m, and numerical aperture is 0.12~0.22.As shown in Figure 4, be the optical device of an integrated filtering functional device 18 and anti-reflection functional device 19.Penetrate in the ceramic insertion core end of multimode fiber 16 and injecting glue is fixed, fiber end face is ground to form 8 ° of inclinations angle, and fiber end face is coated with antireflective coating, be used to suppress the reflection of end face light.With multimode fiber 16 centre position fiber stripping 20mm; Place and draw the about 20 μ m of awl to awl district's diameter to stop on the height of anger; Its awl district is applied high refractive index UV glue, and with a fluting aluminium block package cooling, owing to destroy the total reflection leaded light principle of optical fiber; Filtering does not partly have the ASE light of purposes, reduces the light injury effect to fiber end face.Said functional form multimode fiber 16 can improve ASE power output level significantly, can not produce self-excitation phenomena.Multimode fiber 16 in the present embodiment is 105/125 0.22NA.
As shown in Figure 5, cladding mode stripper 13 used in the present invention is made up of active doubly clad optical fiber 10 (input), passive single cladded fiber 20 (output).The about 10mm of active doubly clad optical fiber 10 fiber stripping length in the present embodiment, the about 25mm of passive single cladded fiber 20 fiber stripping length, both carry out welding, and the naked fine zone of contact is applied high refractive index UV glue and encapsulates, solidifies in one and open in " snakelike " groove aluminium block.High refractive index UV glue and cladding glass form " oppositely " waveguiding structure; The mode that further combines " snakelike " groove curved fiber; Guarantee that after the pump light of inner cladding is accomplished the pumping effect the remaining clad pumping optical of filtering is avoided its damage to output optical fibre, optical device effectively.
As shown in Figure 6, embodiment of the invention output ASE light is through the spectrogram result of portlet scanning after the beam split of 30dB optical coupler; The 10dB spectral width is about 60nm; Cover 1030 ~ 1090nm wave band, its ASE power output is up to 1W, and Output optical power stability has good stability with spectral waveform.
The YDF that multi-stage cascade is used among the present invention is not only applicable to the cascade of same type YDF, is applicable to the cascade combination between the YDF of other big core diameter YDF and different levels of doping, different optical parameter, different length yet.As stated, can realize preferably that the present invention, the foregoing description are merely preferred embodiment of the present invention, be not to be used to limit its practical range.