S shape erbium ytterbium codoped phosphate high gain optical waveguide, optical waveguide laser and optical waveguides amplifier
Technical field
S shape erbium ytterbium codoped phosphate high gain optical waveguide, optical waveguide laser and optical waveguides amplifier belong to the optical communication technique field, relate to optical waveguide technique.
Background technology
Phosphate glass is for rare earth ion (Er
3+, Yb
3+Deng) be a kind of good acceptor material, have good optical physics and photochemical properties, as reaching very high doping content (10
26/ m
3), be difficult for to take place concentration quenching under high doping, fluorescence lifetime long (~ 8ms), thermal stability and conduction is good, physical strength is higher, thereby polarization noise and output power noise that the birefringence that is caused by thermal effect and mechanical stress causes are very low, with it is that matrix can be made the good optical waveguide of gain characteristic, can be used as the LASER Light Source and the image intensifer of optical fiber communication.
At present, utilize technology that Yb codoped phosphate glass prepares optical waveguide as shown in Figure 8, adopt Er3+, Yb3+ codoped phosphate glass (Er
3+: Yb
3+≈ 1: 8) substrate and metal mask utilize electric field assisting ion switching technology with Ag
+, K
+, Na
+Spread to the glass matrix depths, make the matrix district refractive index that diffuses into ion below the metal mask raceway groove hole be higher than the matrix district that does not diffuse into ion below the mask, propagate thereby light is constrained in the high index of refraction matrix district according to total reflection principle, form optical waveguide.
Optical waveguide laser and amplifier all are novel optical communication Laser Devices, also are in the experimental study stage at present.But because they have many advantages that semiconductor laser (now generally use optical communication light source) and fiber amplifier commonly used, semi-conductor amplifier can not be compared, the replacement latter has been must in following optical communication and light are integrated.Semiconductor laser has two outstanding defectives: wavelength stability is poor, with optical fiber coupling difficulty, this undoubtedly to optical communication to narrow linewidth, at a high speed, the broadband caused obstacle with integrated direction development, and is subjected to 1.54 μ m Er of extensive concern now
3+-Yb
3+But optical waveguide laser has low-loss, low noise, narrow linewidth, the running of Wavelength stabilized single mode, easily is coupled with optical fiber, volume little easy of integration, commercially produce advantage cheaply, as the acceptor material (as phosphate) of selecting good combination property is as matrix, and then the laser overall performance is more superior.Compare with fiber amplifier, the unit length gain that optical waveguides amplifier is higher owing to high doping content has, and compact conformation, function is integrated, be well suited for the flexible Application in the finite space, can very easily integrate,, introduce the components and parts of multiple performance brilliance for integrated optical circuit as isolator, phased array waveguide, add-drop multiplexer, modulator, photoswitch, optical cross-connect etc. with many optical devices.
Though the volume that optical waveguide laser and amplifier are little meets the integrated developing direction of light, but its little gain media size (cm magnitude) has limited total gain and has further improved, the work of this respect in the past is confined on gain media to make straight or γ shape branch or some very little waveguides of flexibility are studied, wasted very most gain media space, the output of mW ~ 10mW level that its experiment obtains still can not be satisfied the requirement of stablizing long-distance optical communication at a high speed, so the designer of the utilization of gain media and waveguide form need be improved, the total Shu of laser instrument goes out Gong and Shuais Han and need improve.
Summary of the invention
The technical problem to be solved in the present invention is exactly how to utilize the Yb codoped phosphate glass medium to produce the higher optical waveguide of gain, and improves the output power of corresponding laser instrument and amplifier based on this.
S shape erbium ytterbium codoped phosphate high gain optical waveguide, as shown in Figure 1, comprise Yb codoped phosphate glass matrix 3 and the optical waveguide more than at least one that is buried in the Yb codoped phosphate glass matrix 3, described optical waveguide is the passage that the refractive index of mainly utilizing electric field auxiliary heat ion exchange technique to form in Yb codoped phosphate glass matrix 3 is higher than Yb codoped phosphate glass matrix 3, it is characterized in that described optical waveguide is made up of two sections straight wave guides 1 and S shape waveguide 2.
As shown in Figure 2, described optical waveguide also can be made the two S shape optical waveguides of three ports, has three sections straight wave guides 1 and two sections S shapes waveguide 2.
Its waveguide aperture is slightly larger than single-mode optics fibre core warp, is about about 10 μ m.
The curved waveguide part of S shape is by two tangent being formed by connecting of circular arc that are slightly less than 3/4 girth, promptly two 3/4 circular arcs produce the overlapping of certain-length in the junction, so that waveguide bend place formation certain distance (〉 the 10 μ ms mutually close) with straight wave guide, thereby the light of avoiding separately being transmitted produces coupling, and the waveguide bend end all is connected with straight wave guide is tangent.
Its gain of optical waveguide of the present invention is for being about 2B/cm, and is relevant with the material composition of glass matrix.Straight wave guide, the waveguide of S shape all are made on the phosphate gain media substrate 3 by technologies such as plated film, photoetching, the exchanges of burn into electric field assisting ion, form and bury waveguide to reduce radiation loss.It is big as far as possible that radius-of-curvature should be done under the prerequisite that makes full use of the host material space, and avoid producing the curvature mutation part, to reduce bending loss as far as possible.
S shape erbium ytterbium codoped phosphate high gain optical waveguide laser instrument, shown in Fig. 3,4, partly form by 980nmLD pump laser 6, coupled fiber 5, high reflectance fiber grating 4, optical waveguide resonator cavity 9, antiradar reflectivity fiber grating 7, coupled fiber 5 etc., each several part is continuous in proper order, it is characterized in that described optical waveguide resonator cavity is a S shape erbium ytterbium codoped phosphate high gain optical waveguide of the present invention.
The connected mode of S shape erbium ytterbium codoped phosphate high gain optical waveguide and coupled fiber/grating fibers can be bonding with fixing glue, and the connection of other parts can be coupled by coupling mechanism, also can connect by the mode of optical fiber splicer coupling.
For further improving gain, can between antiradar reflectivity fiber grating 7 and coupled fiber 5, increase a 980nm pump laser 6 and do reverse LD pumping by coupling mechanism 10.
The reflectivity of described high reflectance fiber grating 4 is greater than 95%, and the reflectivity of described antiradar reflectivity fiber grating 7 is between 80-90%.
The principle of work of S shape erbium ytterbium codoped phosphate high gain optical waveguide laser instrument is: the 980nm laser of LD pumping source emission is coupled into the gain media waveguide through fiber grating, Yb in the Medium Wave Guide
3+Concentration is very big (to be generally Er
3+4 ~ 20 times), have the Er of ratio
3+Bigger absorption cross section, this makes luminous energy by Yb
3+Strong absorption, Er
3+Concentration is less, thereby is in Yb
3+Encirclement among, so Yb
3+Luminous energy can be passed to Er rapidly
3+, make Er
3+From the ground state transition to excited state and produce 1.54 μ m fluorescence, fiber grating 4 and 7 is equivalent to constitute the high and low catoptron of laserresonator, under the acting in conjunction of pumping source, S shape erbium ytterbium codoped phosphate high gain optical waveguide and fiber grating 4,7, pump energy is constantly by Yb
3+Absorb and be passed to Er
3+, make Er
3+Constantly gather and form population inversion at last energy level, 1.54 μ m fluorescence constantly obtain amplifying and form 1.54 μ m laser generations, export to outside the system from fiber grating 7 ends that hang down reflection.Increase counter-directional pump source and make the working gain waveguide absorb more pump energies in the identical time, respond faster, the rare earth ion of working is fully used, and light energy output is further increased.
S shape erbium ytterbium codoped phosphate high gain optical waveguide amplifier, shown in Fig. 5,6, partly form by 980nmLD pump laser 6, coupled fiber 5, coupling mechanism 10, optical waveguide 9 etc., 980nmLD pump laser 6 and link to each other with the input end of optical waveguide 9 by coupling mechanism 10, coupled fiber 5 respectively as the coupled fiber 5 of input, the output terminal of optical waveguide 9 links to each other with coupled fiber 5, it is characterized in that described optical waveguide 9 is a S shape erbium ytterbium codoped phosphate high gain optical waveguide of the present invention.
The connected mode of S shape erbium ytterbium codoped phosphate high gain optical waveguide and coupled fiber/grating fibers can be bonding with fixing glue, and the connection of other parts can be coupled by coupling mechanism, also can connect by the mode of optical fiber splicer coupling.
For further improving gain, can be coupled a 980nm pump laser 6 as oppositely LD pumping by coupling mechanism 10 at the waveguide output terminal.
The principle of work of S shape erbium ytterbium codoped phosphate high gain optical waveguide amplifier: during as amplifier, do not need to be used as in the laser instrument light fiber grating of cavity mirror, just need to increase the flashlight I/O end as shown in accompanying drawing 5,6, the same with situation in the laser instrument, because the excitation of forward and reverse LD pumping makes the Yb in the Medium Wave Guide
3+The absorbing light energy also passes to Er
3+, Er
3+Be activated to upper state in a large number, the decay in the telecommunication optical fiber light signal in being coupled into S shape erbium ytterbium codoped phosphate high gain optical waveguide the time, make the Er that yards up in a large number in upper state
3+Brought out and downward energy level transition, i.e. induced transition is restored thereby make the flashlight of having decayed obtain amplifying, and is coupled into optical fiber again from output terminal then and transmits.
The loss of laser instrument and amplifier is analyzed with gain:
(1) reduce the method for loss: 1. added electric field makes ions diffusion enter glass matrix to form and bury the shape waveguide, the refringence of waveguide and glass matrix is tried one's best greatly to reduce scattering loss during ion-exchange; 2.S it is big and avoid curvature mutation to reduce crooked radiation mode loss that the radius-of-curvature of shape is done as far as possible: 3. bury the waveguide aperture be larger than fiber cores through be convenient to be coupled and aligned and mould field coupling to reduce coupling loss; 4. using optical fibre grating replaces coupled lens and resonator surface catoptron to reduce to insert loss and coupling loss; 5. choose the matrix of composition reasonable mixture ratio, reduce OH
-Absorption to luminous energy.
(2) improve gain method: 1. making full use of the glass matrix space increases gain waveguide length: 2. make the waveguide of a plurality of S shape and adopt a plurality of pumping source pumpings (as accompanying drawing 4,6); 3. adopt two-way LD pumping; 4. choose Er
3+-Yb
3+The glass matrix that concentration ratio is suitable, in the inhibition conversion give out light, Er
3+→ Yb
3+Energy back transfer and excited state absorption are to the influence of laser activity.
Beneficial effect of the present invention:
1, compares with straight wave guide, become S shape not only effectively to utilize the gain media space waveguide design, and prolonged the gain length of waveguide greatly, and loss is very little, fully having improved output power, also is the outstanding selection of optical system to the integrated direction development.
2, owing to the coupling of the pattern form in pattern form in the waveguide and the optical fiber, so output light can directly be coupled into optical fiber, each building block volume of this high gain optical waveguide system all very little (centimetre magnitude), can be integrated on a slice glass substrate material, thereby make more compact structure, operate more stablely, be easy to industrialization.
3, on matrix, make one or two even the gain waveguide of many S shapes, thereby can realize that one or two or a plurality of pumping source pumping improve output.
4, help the integrated of various laser optical waveguide system.
Using value of the present invention: this laser system is as the LASER Light Source of high-speed wideband long-distance optical communication or the image intensifer on the optical communication line, and its unique advantage and running performance are arranged in integrated optical circuit.
Description of drawings
Fig. 1 list S shape erbium ytterbium codoped phosphate high gain optical waveguide structural representation, wherein, 1 is straight wave guide, and 2 is the waveguide of S shape, and 3 is the Yb codoped phosphate glass medium.
The two S shape erbium ytterbium codoped phosphate high gain optical waveguide structural representations of Fig. 2, wherein, 1 is straight wave guide, and 2 is the waveguide of S shape, and 3 is the Yb codoped phosphate glass medium.
Fig. 3 is based on the laser structure synoptic diagram of single S shape erbium ytterbium codoped phosphate high gain optical waveguide, wherein, 4 is the high reflectance fiber grating, 5 is coupled fiber, 6 is the 980nmLD pump laser, 7 is the antiradar reflectivity fiber grating, and 9 is S shape erbium ytterbium codoped phosphate high gain optical waveguide (optical waveguide resonator cavity), and 10 is coupling mechanism.
Fig. 4 is based on the laser structure synoptic diagram of two S shape erbium ytterbium codoped phosphate high gain optical waveguides, wherein, 4 is the high reflectance fiber grating, 5 is coupled fiber, 6 is the 980nmLD pump laser, 7 is the antiradar reflectivity fiber grating, and 9 is S shape erbium ytterbium codoped phosphate high gain optical waveguide (optical waveguide resonator cavity), and 10 is coupling mechanism.
Fig. 5 is based on the amplifier architecture synoptic diagram of single S shape erbium ytterbium codoped phosphate high gain optical waveguide, and wherein, 5 is coupled fiber, and 6 is the 980nmLD pump laser, and 9 is S shape erbium ytterbium codoped phosphate high gain optical waveguide, and 10 is coupling mechanism.
Fig. 6 is based on the amplifier architecture synoptic diagram of two S shape erbium ytterbium codoped phosphate high gain optical waveguides, and wherein, 5 is coupled fiber, and 6 is the 980nmLD pump laser, and 9 is S shape erbium ytterbium codoped phosphate high gain optical waveguide, and 10 is coupling mechanism.
Fig. 7 electric field auxiliary heat ion interchange unit synoptic diagram.
Fig. 8 fiber waveguide device forms process flow diagram.
Fig. 9 straight wave guide cross section structure synoptic diagram, wherein, 1 is straight wave guide, 3 is the Yb codoped phosphate glass medium.
Embodiment
S shape erbium ytterbium codoped phosphate high gain optical waveguide, as shown in Figure 1, comprise Yb codoped phosphate glass matrix 3 and be buried in the optical waveguide more than at least one in the Yb codoped phosphate glass matrix 3 that described optical waveguide is the passage that the refractive index of mainly utilizing electric field auxiliary heat ion exchange technique to form is higher than Yb codoped phosphate glass matrix 3 in Yb codoped phosphate glass matrix 3.Described optical waveguide is made up of two sections straight wave guides 1 and S shape waveguide 2.Described S shape waveguide 2 is by two tangent being formed by connecting of circular arc that are slightly less than 3/4 girth, promptly two 3/4 circular arcs produce the overlapping of certain-length in the junction, so that waveguide bend place formation certain distance (〉 the 10 μ ms mutually close) with straight wave guide, thereby the light of avoiding separately being transmitted produces coupling, and the waveguide bend end all is connected with straight wave guide is tangent.Whole S shape erbium ytterbium codoped phosphate high gain optical waveguide aperture is slightly larger than single-mode optics fibre core warp, is about about 10 μ m.
As shown in Figure 2, described S shape erbium ytterbium codoped phosphate high gain optical waveguide also can be made the two S shape optical waveguides of three ports, has three sections straight wave guides 1 and two sections S shapes waveguide 2.
S shape erbium ytterbium codoped phosphate high gain optical waveguide laser instrument, shown in Fig. 3,4, partly form by 980nmLD pump laser 6, coupled fiber 5, high reflectance fiber grating 4, optical waveguide resonator cavity 9, antiradar reflectivity fiber grating 7, coupled fiber 5 etc., each several part is continuous in proper order, it is characterized in that described optical waveguide resonator cavity is a S shape erbium ytterbium codoped phosphate high gain optical waveguide of the present invention.
The connected mode of S shape erbium ytterbium codoped phosphate high gain optical waveguide and coupled fiber/grating fibers can be bonding with fixing glue, and the connection of other parts can be coupled by coupling mechanism, also can connect by the mode of optical fiber splicer coupling.
For further improving gain, can between antiradar reflectivity fiber grating 7 and coupled fiber 5, increase a 980nm pump laser 6 and do reverse LD pumping by coupling mechanism 10.
The reflectivity of described high reflectance fiber grating 4 is greater than 95%, and the reflectivity of described antiradar reflectivity fiber grating 7 is between 80-90%.
S shape erbium ytterbium codoped phosphate high gain optical waveguide amplifier, shown in Fig. 5,6, partly form by 980nmLD pump laser 6, coupled fiber 5, coupling mechanism 10, optical waveguide 9 etc., 980nmLD pump laser 6 and link to each other with the input end of optical waveguide 9 by coupling mechanism 10, coupled fiber 5 respectively as the coupled fiber 5 of input, the output terminal of optical waveguide 9 links to each other with coupled fiber 5, it is characterized in that described optical waveguide 9 is a S shape erbium ytterbium codoped phosphate high gain optical waveguide of the present invention.
The connected mode of S shape erbium ytterbium codoped phosphate high gain optical waveguide and coupled fiber/grating fibers can be bonding with fixing glue, and the connection of other parts can be coupled by coupling mechanism, also can connect by the mode of optical fiber splicer coupling.
For further improving gain, can be coupled a 980nm pump laser 6 as oppositely LD pumping by coupling mechanism 10 at the waveguide output terminal.