EP0478755A1 - Diode laser a haute puissance - Google Patents

Diode laser a haute puissance

Info

Publication number
EP0478755A1
EP0478755A1 EP91908495A EP91908495A EP0478755A1 EP 0478755 A1 EP0478755 A1 EP 0478755A1 EP 91908495 A EP91908495 A EP 91908495A EP 91908495 A EP91908495 A EP 91908495A EP 0478755 A1 EP0478755 A1 EP 0478755A1
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EP
European Patent Office
Prior art keywords
region
main
active region
regions
active
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP91908495A
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German (de)
English (en)
Inventor
Iulian Basarab Petrescu-Prahova
Sorina Lazanu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
INSTITUTUL DE FIZICA ATOMICA
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INSTITUTUL DE FIZICA ATOMICA
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Publication of EP0478755A1 publication Critical patent/EP0478755A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/1039—Details on the cavity length
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/2004—Confining in the direction perpendicular to the layer structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/2004—Confining in the direction perpendicular to the layer structure
    • H01S5/2018—Optical confinement, e.g. absorbing-, reflecting- or waveguide-layers
    • H01S5/2031—Optical confinement, e.g. absorbing-, reflecting- or waveguide-layers characterized by special waveguide layers, e.g. asymmetric waveguide layers or defined bandgap discontinuities
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/305—Structure or shape of the active region; Materials used for the active region characterised by the doping materials used in the laser structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/32—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures
    • H01S5/3211—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities
    • H01S5/3213—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities asymmetric clading layers

Definitions

  • This invention relates to high power laser diodes which can be used for laser emission at increased densities of the radiation flux and in the fundamental transverse mode.
  • the absorbtion of the laser radiation flux followed by the dissipation of the absorbed energy in nonradiative processes, produces an initial local heating which in its turn induces the decrease of the band gap and, further on, the increase of absorbtion and heating phenomena rates etc.
  • the absorbtion and heating processes succeed each other so fast that they lead to the catastrophic degradation phenomenon, the intensity of which depends on the magnitude of the surface recombination rates and on the magnitude of tne laser radiation flux density reaching the surface and being absorbed.
  • the majority of laser diodes are fabricated from a succession of epitaxial, parallel layers, including the active layer, and the Fabry-Perot resonator mirrors are obtained by cleaving the semiconductor crystal perpendicular to the plane of the epitaxial layers, so that they inherently conserve the disadvantage of the catastrophic degradation at relatively small radiation flux densities, due to high value of the surface recombination at the active region-external medium interface.
  • laser diodes with transparent mirrors whereat the radiation flux density can be increased by diminishing the surface recombination rate and the influence of mirror absorbtion mechanisms.
  • Such a type of laser diodes presents an active region terminated in the mirror unitedity with a transparent semiconductor material, with a larger than that of the active region band gap, so that the absorbtion mechanisms at the semiconductor material-external medium interface are completely eliminated and, at the active region-transparent medium interface, the interface recombination rate is reduced, the decrease of the carri er concentration i s also reduced, so that the interface absorbtion of the incident flux on the interface is also reduced.
  • Transparent mirror laser diodes have the disadvantage that for fabricating the transparent region microlithographic, etching and epitaxial growth processes are needed and the mirrors need to be produced by cleaving in a relatively narrow, 20 - 50 ⁇ m wide region.
  • Laser diodes (Great Britain Patent BB 2031644 A) formed from structures with 4 or 5 layers wherein one of the layers is used mainly as a waveguide and is adjoined to the active layer or is separated from this one by a carrier confinement layer so that the radiation flux is distributed both in the active layer and in the waveguide are also known. These diodes present the disadvantage that the thickness of the waveguide is not greater than 2 ⁇ m and that the operation in higher order transverse mode in the widest proposed waveguides is possible.
  • the aim of this invention is to fabricate laser diodes with as high as possible values for the flux density and for the total emitted flux.
  • the problem which is solved by this invention is to fabricate laser diodes formed by epitaxial, parallel between the two mirrors, layers, with the wavequide main region separated from the active one, diodes having a very small magnitude of the radiation flux in the active region.
  • the high power laser diode resolves this problem using a structure consisting of a substrate, a limitation region, a main region, an intermediate region, an active region, on excitation region and a contact region, wherein the refractive index of the active region is the hiqhest in the structure, wherein the refractive index of the main region is the next lnferior one, wherein the product ot the active region thickness by the square root of the difference of the squares of the refractive indexes of active, respectively main regions is smaller than a quarter of the vacuum wavelength of the laser radiation, wherein excitation and intermediate regions have conductivity types opposite to each other, in order to opperate at high radiation flux densities and to allow only ths propagation of the fundamental transverse mode the maximum radiation flux of which i s located in the main region and the effective retractive index or which is comprised between the refractive index values of the limitation and of the main regions, the product of the main region thickness by the square root of the difference of the squares of retract
  • FIG. 1 is a perspective view of the laser diode
  • FIG. 2 is a graph of the radiation flux density as a function of the coordinate perpendicular to tne waveguide structure
  • FIG.3 is a graph of the refractive index of the semiconductor materials as a function of the coordinate perpendicular to the waveguide structure.
  • the laser diode according to the invention consists of the following layers; a substrate 1, a limitation region 2, a main region 3, an intermediate region 4, ar active region 5, an excitation region 6 and a contact region 7.
  • the regions 1...7 consists of semiconductor materials.
  • the external region 1 is covered with a metallic contact 8 and the external region 7 with a metallic contact 9.
  • the metallic contacts 8 and 9 allow the flow of an electrical exciting current through the laser diode when an external voltage V ext , with the proper polarity, is applied.
  • the waveguide, consisting of regions 2...6, terminates at one side with a semiconductor material- external medium interface 10 and at the other side with a semiconductor material-external medium interface 11. These two interfaces are plan parallel to each other and perpendicular to the waveguide structure and represent the Fabry-Perot resonator mirrors.
  • the spatial disposal of the laser diode presented in FIG. 1 is refered to an orthogonal coordination system Oxys.
  • Oxys orthogonal coordination system
  • a laser diode with a very large width w in the y direction is considered and the laser radiation along the y direction is supposed uniform.
  • the radiation propagates along the waveguide in z direction.
  • the mirrors 10 and 11 are parallel to the xy plane.
  • a cross-section parallel to the xy plane is considered.
  • a graph 12 which represents the I(x) function in a (I,x) coordinate system is shown. The shape of the graph is the same in every transverse cross-section parallel to the xy plane.
  • a flux df is passing through the w*dx area of the transverse cross-section:
  • the limitation region 2 extends from a coordinate x 1 to coordinate X 2 , the main region 3 from the coordinate X 2 to coordinate x 3 , the intermediate region 4 from the coordinate x 3 to a coordinate x 4 , the active region 5 from the coordinate x 4 to a coordinate x 5 , the excitation region from the coordinate x 5 to a coordinate x 6 and the contact region from the coordinate x 6 to a coordinate x 7 .
  • the function I(x) has a maximum value of the radiation flux in the active region, I max , and a maximum value of the radiation flux density in the active region I m.a. .
  • the sum of the flux density in the whole (x 1 , x 6 ) interval of the laser diode structure determines a value of the total flux, F
  • the sum of the flux density in the (X 4 ,x 5 ) interval determines a value f a of the flux passing through the active region cross-section.
  • the emitted flux passing through the active region, f a is proportional to the double hatched area in FIG. 2 and the total radiation flux F passing through the whole cross- section is proportional to the hatched area, including the double hatched one.
  • the confinement factor T is the subunitar ratio:
  • the function has the main maximum value inside the main region and asymtoticaly decreases to zero in the excitation 6 and limitation 2 regions.
  • the operation in the fundamental transverse mode is important both for applications wherein laser diode radiation is transmited through optical fibers and for those wherein it is transmited into atmosphere through collimating systems.
  • FIG. 3 presents a graph 13 of the dependence on the coordinate x of the refractive index n of the semiconductor materials constituting the epitaxial structure in a coordinate system (n,x).
  • the refractive indexes are supposed constant in every region.
  • the active region 5 has a value n 5 of the refractive index which is the maximum value.
  • the main region 3 has a value n 3 which is next inferior to the n 5 value.
  • a relation between the active region 5 thickness, d a , and the refractive index difference (n 5 - n 3 ) is imposed so that the propagation of any mode with an effective refractive index value n eff between n 3 and n 5 values is not possible.
  • the conditioning relation for the cut off of the modes with n 5 ⁇ n eff ⁇ n 3 is: (3) or, approximately:
  • the intermediate region 4 has a refractive index value n 4 and the excitation region 6 a refractive index value n 6 , values firstly determined by the energy band gaps of the semiconductor materials constituting the respective regions, energy band gaps which should be high enough compared to the energy band gap of the active region 5, to build effective potential barriers for the nonequilibrium carriers, electrons and holes, in their paths from the active region 5 toward the adjoining regions and to provide the carrier confinement effect.
  • the regions adjoined to the active region 5, namely the intermediate region 4 ana the excitation region 6 have conductvity types, n or p, opposite to each other, so that between them there is a p-n junction for the active region 5 excitation.
  • the active region 5 has the conductivity type either n or p, or can consist of undoped semiconductor material, or can include the p-n junction.
  • the intermediate region 4 should be thick enough in order to avoid the nonequilibrium carrier tunneling.
  • the thickness of an effective potential barrier dependes on the carrier effective mass and on the barrier height which in its turn depends on the difference between the intermediate region 4 and the active region 5 energy band gaps.
  • the intermediate region thickness should be larger than 0,03 ⁇ m.
  • K is a numerical coefficient between 0.5 and 1.
  • the l m.a. value is limited by catastrophic degradation phenomena.
  • I m.a. values of the order of 10 6 W/cm 2 are known. If I m.a. value is limited, to obtain as high as possible values for F, as low as possible values for are needed. Values for from 1,5*10 -4 to
  • the refractive index n 2 of the limiting region 2 must be sufficiently close to the n 3 value in order to avoid the propagation of other than the fundamental transverse mode.
  • the condition for higher order transverse mode cut off is expressed as a function of refraction indexes n 2 , n 3 , and n 5 and of the active region 5 and main region 3 thicknesses, d a and d m , by the relation:
  • the main region 3 thickness, d m is choosed from 2 to 5 ⁇ m, in relation to the desired width of the laser beam and to the desired total flux. For these thicrnesses, 2 ⁇ m and 5 ⁇ m, the differences between the retractive indexes n 3 and n 2 should be
  • the active region 5 When the semiconductor material of the active region 5 is excited by the current flow through the p-n junction, in the active region 5 nonequilibrium carriers, electron and holes, appear and they recombine by photon emission.
  • the stimulated emission determines a gain coefficient of the active region, g a .
  • the cut off condition for modes with n ef f between n 3 and n 5 determines the spreading of the electromagnetic radiation outside the active region 5, mainly in the waveguide main region 3. Due to this spreading the wave in the guide has a modal gain coefficient 6 proportional to the intrinsec active region gain coefficient g a and to :
  • excitation of the active region 5 is needed in order to obtain a modal gain coefficient to exceed the losses.
  • Values in the order of magnitude of 1000 cm -1 for the active region gain coefficient g a are proposed in this invention so that the active region 5 is highly excited by high concentrations of the nonequilibrium carriers, radiative recombination of which produces the stimulated emission.
  • nonradiative surface recombination processes are produced, supplementary to the bulk, radiative ones so that there is a decrease toward the surface of the excitation level of the active region 5, expressed by the noneguilibrium carrier concentrations. This decrease determines the replacement of the wave amplification by its attenuation, due to absorbtion.
  • the absorbtion generates nonequilibrium carriers in the internity of the semiconductor material-external medium interfaces 10 and 11, carri ers, which nonradiatively recombine on the surface and produce the initial local heating.
  • the initial local heating is relatively small due to the separation, produced by the intermediate region 4, of the main region 3, wherein the almost entire laser radiation is nonabsorbely emitted at interfaces 10 and 11, from the active region 5, wherein, at interfaces 10 and 11, recombination and absorbtion processes occure.
  • the local heating of the active region 5 is proportional to the radiation flux density in this region, which is small compared to the maximum radiation flux density.
  • the local heating reaches the critical value for producing the catastrophic degradation at a critical value I m.a.cr. of the maximum flux density in the active region 5, critical value which is approximately equal to the radiation flux density which produces the catastrophic degradation for a diode wherein the maximum of the flux density is in the active region.
  • F cr k*I m.a.cr. *d a *w/ (9) and smaller the value greater the F cr value.
  • the aim of the invention is to provide as great, as possible laser radiation total flux using as small as possible values.
  • the limit for the catastrophic degradation obviously appears another limitation, namely that due to active region heating.
  • the active region heating is produced by the dissipation of spontaneous recombination energy necessary to reach the threshold condition and by the Joule effect.
  • Resonators with the back mirror reflectivity R 1 1, obtained by dielectric or dielectric-metals coatings, will be considered firstly.
  • the other mirror reflectivity R 2 can be the natural one or, by the mentioned coating methods, can be varied between large limits, for example between 0.01 and 0.62.
  • Mirror losses can be expresed by a loss coefficient ⁇ , given by the relation:
  • Free carrier absorbtion lasses in the active region will be considered as the main wave attenuation mechanism inside the waveguide.
  • Other possible mechanisms are the attenuation due to free carrier absorbtion in the other waveguide regions and the attenuation due to the light scattering on inhomoqenitIes at waveguide interfaces or inside the waveguide.
  • Free carrier absorbtion in the active region 5 determines an intrinsec absorbtion coefficient ⁇ a . Due to this absorbtion, the attenuation of the waveguide is characterised by an attenuation coefficient ⁇ .
  • the relation between ⁇ and ⁇ a is analogous to (8): (12)
  • the laser diode according to the invention should work at ⁇ values between 0.033 and 0.33 cm -1 . Such low values are possible only due to low values and assuming that the free carri er absorbtion in the active region is the main loss mechanism.
  • Total losses coefficient, due to mirror transmission and losses inside the cavity, ⁇ + ⁇ , has a value between 0.133 and
  • the intrinsec active region gain g a G/ should be approximately 890 cm -1 .
  • Such a value for the active region gain can be obtainec if the volume current density J vth of the threshold recombination current is in the order of magnitude of 3*10 4 A/cm 2 / ⁇ m and if, correspondingly, free carrier concentration is 2-3*10 18 cm -3 , what, corresponds to absorbtion coefficients of 40-60 cm -1 , so that the mentioned value 200 cm -1 is indeed a safety value.
  • volume current density J v should be few times greater than the volume current density at threshold, J vth .
  • the increase in the volume current density J v is limited by the surface current density J s , the value of which determines the active region heating, and by the active region thickness by the relation:
  • the radiation flux obtained in an active region of length L, width w and thickness d a is:
  • the optimum thickness of the active region can be determined from the formulae (9) and (14). Such optimum thicknesses of the active region are 0.045 ⁇ m and
  • the active region 0.11 ⁇ m, respectively 0.26 ⁇ m.
  • the active layer thickness can be greater, but can not exceed 0.32 ⁇ m, as will be further shown.
  • the active region thickness depends on the difference of refractive indexes n 5 and n 3 .
  • the values of the refractive indexes n 3 and n 5 are related to the corresponding energy band gap values of the semiconductor materials of the main region 3 and active region 5, and these values determine the emitted photon energies in the active region 5 and the band to band absorbtion coefficient for these photons in the main region 3.
  • the n 3 and n 5 values and the corresponding band gaps should be so that the mentioned absorbtion coeficient is as small as possible, what means that the main region 3 is as transparent as possible for the radiation emitted in the active region.
  • the main region consists of an n type semiconductor and the energy gap of the main region 3 to be at least 120 meV greater than the energy of the emitted photons, to avoid band tail absorbtion.
  • the energy gap of the main region 3 to be at least 120 meV greater than the energy of the emitted photons, to avoid band tail absorbtion.
  • the mam region 3 impurity doping should be kept to low concentration values to reduce free carrier losses and to avoid band tail absorbtion.
  • Free carrier absorbtion in the main region should be smaller than 0.033 cm -1 , respectively 0.33 cm -1
  • the free carrier concentration should be smaller than 10 16 cm -3 , respectively 10 17 cm -3 , for laser diodes with equal to
  • the doping levels should be kept under 10 17 cm -3 in the intermediate region 4 and excitation region 6, too.
  • a first example of laser diode according to the invention is a structure in the AlGaAs system, with difterent values of the composition indexes and layer thicknesses.
  • Al y Ga 1- y As system is choosed to illustrate the invention since the material constants are better known.
  • ternary compounds Al x In 1- x P, Al x ln 1- x As, Al x Ga 1-x Sb, Al x In 1- x Sb, Ga x In 1- x P, Ga x In 1-x As, Ga x In 1-x Sb, GaP x As 1-x , GaAs x Sb 1-x , InP x As 1-x , InAs x Sb 1- x ; and quaternary: Al x Ga 1-x As y P 1-y , Al x Ga 1-x AS y Sb 1-y , Ga x In 1-x P y As 1-y , Ga x In 1-x As y Sb 1-y , (Al x Ga 1-x ) y In 1-y P, (Al x Ga 1- x ) y In 1-y AS, (Al x Ga 1 - x ) y In 1 -y Sb , In (P x As 1-x ) y Sb 1-y .
  • the confinement factor ot this structure is 1.5*10 -4 . Due to the relatively high active region thickness this structure is suitted for the quasicontinuous regime. The estimated total flux emitted without the appearance of the catastrophic degradation is
  • the second example is a laser diode wherein the main, intermediate and active region thicknesses are modified, according to tab. 2:
  • the confinement factor of this structure is 1.5*10 -4 , as in the previous example.
  • the smaller active region thickness indicate this structure for the continuous regime.
  • the total flux emitted without the appearance of the catastrophic degradation is
  • the smaller than in the first example value of the emitted flux is related to a smaller value for the active region thickness.
  • the third example refers also to a laser diode with a 2.3 cm Iength but with 1, respectively 0.01, reflectivities.
  • a diode can wort if the confinement factor is greater than in the previous cases, for exam ⁇ le 1.5*10 -3 .
  • Refraictive indexes and the layer thicknesses are pesented in tab. 3:
  • This diode is indicated for the continous regime and the total flux emitted without the appearance of the catastrophic degrdration can be estimated to be 0.38 kW per mm of the diode width in the p-n junction plane.
  • the smaller flux compared to that of the second example structure is related to the higher confinement factor value.
  • the forth example refers to laser diode wherein the main, intermediate and active region thicknesses are modified comparatively to the previous example, according to the tab. 4:
  • This diode is indicated for the quasicontinuous regime.
  • the flux emitted without the appearance of the catastrophic degradation is aproximately 0.95 kW per mm of the diode width in the p-n junction plane.
  • the active region refractive index has for this photon energy a mediated value approximately equal to 3.57.
  • the band gap of the main region is 1.64 eV, 0.17 eV greater than the energy of the emitted photons. To this value of the photon energy corresponds a refractive index value equal to 3.53.
  • the fifths example is constructed, described in tab. 5:
  • the confinement factor of this structure is 1.5*10 -3 . Since the active region consists of quantum wells the diode will work with a reduced threshold current compared to that of the third example to which the diode has closed layer thickness and coefficient values. The flux emitted without the appearance of the catastrophic degradation is 0.38 kW/mm as in the third example.
  • the band gap of the main region should be at least 200 meV greater than the active region band gap and the active region thickness should be smaller than 0.25 ⁇ m.
  • the confinement factor is 3.5*10 -3 , respectively 1.1*10 -4 , for structures with the main region thicknesses of 2, respectively 5 ⁇ m.
  • the laser diodes according to the invention present the advantage that they work at hign densities o f the radiation fluxes and also at high total flux, being constructed from simple structures with parallel between the two mirrors epitaxial layers.

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  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)

Abstract

Diode laser à haute puissance qui est constituée par une zone d'excitation et qui possède un facteur de limitation situé entre 1,5*10-4 et 1,5*10-3 et une longueur de résonateur située entre 1,5 et 3cm, dans laquelle seul peut se propager le mode transversal fondamental possédant le maximum de la densité de flux située dans la zone principale, à cause d'une différence minime d'indice de réfraction entre les zones principale et de limitation.
EP91908495A 1990-04-20 1991-04-04 Diode laser a haute puissance Withdrawn EP0478755A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
RO14489490A RO102871B1 (en) 1990-04-20 1990-04-20 High power laser diode
RO144894 1990-04-20

Publications (1)

Publication Number Publication Date
EP0478755A1 true EP0478755A1 (fr) 1992-04-08

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EP91908495A Withdrawn EP0478755A1 (fr) 1990-04-20 1991-04-04 Diode laser a haute puissance

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EP (1) EP0478755A1 (fr)
IL (1) IL97898A0 (fr)
RO (1) RO102871B1 (fr)
WO (1) WO1991016747A1 (fr)

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Publication number Priority date Publication date Assignee Title
RO109906B1 (ro) * 1994-09-09 1995-06-30 Prahova Iulian Basara Petrescu Dioda laser, de mare putere
US6810063B1 (en) 1999-06-09 2004-10-26 The Furukawa Electric Co., Ltd. Semiconductor laser device
JP2001148537A (ja) * 1999-11-18 2001-05-29 Nec Corp 半導体レーザ
FR2831723B1 (fr) 2001-10-31 2004-02-06 Cit Alcatel Laser a semi-conducteurs
US6724795B2 (en) 2002-05-10 2004-04-20 Bookham Technology, Plc Semiconductor laser
FI20085512A0 (fi) * 2008-05-28 2008-05-28 Oulun Yliopisto Puolijohdelaser
DE102009041934A1 (de) 2009-09-17 2011-03-24 Osram Opto Semiconductors Gmbh Kantenemittierender Halbleiterlaser

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US3733561A (en) * 1971-07-27 1973-05-15 Bell Telephone Labor Inc High power, fundamental transverse mode operation in double heterostructure lasers
US3855607A (en) * 1973-05-29 1974-12-17 Rca Corp Semiconductor injection laser with reduced divergence of emitted beam
NL184715C (nl) * 1978-09-20 1989-10-02 Hitachi Ltd Halfgeleiderlaserinrichting.
JPH01264286A (ja) * 1988-04-15 1989-10-20 Omron Tateisi Electron Co 半導体量子井戸レーザ
JPH0212885A (ja) * 1988-06-29 1990-01-17 Nec Corp 半導体レーザ及びその出射ビームの垂直放射角の制御方法
DE3838016A1 (de) * 1988-11-09 1990-05-10 Siemens Ag Halbleiterlaser im system gaa1inas

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Title
See references of WO9116747A1 *

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Publication number Publication date
WO1991016747A1 (fr) 1991-10-31
IL97898A0 (en) 1992-06-21
RO102871B1 (en) 1993-08-16

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