RU2691164C1 - Pulse injection laser - Google Patents

Abstract

FIELD: physics.SUBSTANCE: pulsed injection laser comprises a separate restriction heterostructure, comprising an asymmetric multimode waveguide, limiting layers (3), (8) of which simultaneously are emitters of n- and p-type conductivity with identical refraction indices, active region (6) consisting of at least one quantum-size active layer, optical facets (11), (13), ohmic contacts (2), (10) and an optical resonator formed by optical facets (11), (13). Waveguide region on the side of emitter (3) of n-type conductivity consists of two layers (4), (5) of semiconductor material, having the same refraction index. First layer (5) adjacent to active region (6) has doping level Ncm, and thickness d, mcm, satisfying certain ratios. Second layer (4) adjacent to emitter (3) of n-type conductivity has level of doping not more than background level of doping and thickness d= (d-d).EFFECT: technical result consists in enabling increase in maximum peak power with simultaneous reduction of radiation spectrum width.1 cl, 3 dwg

Description

The invention relates to quantum electronics, and more specifically to semiconductor lasers, and can be used to create high-power pulsed semiconductor lasers for pumping nonlinear crystals, fiber amplifiers and solid-state lasers.

When choosing the design of high-power semiconductor lasers, considerable attention is paid to the issues of obtaining high values of the output optical power, high differential current efficiency and spectral homogeneity in all current-pump modes. Such lasers can be obtained only on the basis of heterostructures with low internal optical losses; therefore, minimizing the internal optical losses is the most important condition for creating high-power semiconductor lasers. The most promising for this purpose were the quantum-size heterostructures of separate constraints (DGS PO).

Known pulsed injection laser (see application US 20130287057, IPC H01S 5/20, published 10/31/2013), containing a heterostructure separate restrictions, consisting of the first restrictive layer of n-type conductivity, the first waveguide layer of n-type conductivity, adjacent to the first restrictive layer, the active layer adjacent to the first waveguide layer, the second waveguide layer of p-type conductivity, adjacent to the active layer, the second restrictive layer of p-type conductivity, adjacent to the second waveguide layer. The sum of the thicknesses of the first waveguide layer, the active layer and the second waveguide layer is more than 1 μm, and the thickness of the second waveguide layer is less than 150 nm. In addition, the active layer, the first restrictive layer, the second restrictive layer, the first waveguide layer and the second waveguide layer are such that the maximum intensity of the fundamental mode is in the region outside the active layer, and the difference between the refractive indices of the first waveguide layer and the first restrictive layer lies in the range between 0.04 and 0.01. Known injection laser has an asymmetric waveguide. The main part of the laser mode propagates through the first waveguide layer. The low contrast of the refractive index between the first restrictive layer and the first waveguide layer ensures the leakage of high-order modes from the waveguide and a decrease in their optical confinement factor in the active region, due to which high-order modes do not participate in lasing. The expansion of the waveguide allows you to narrow the radiation pattern of the laser beam in a plane perpendicular to the layers of the structure to values less than 50 degrees (beam width containing 95% of optical power).

The main disadvantage of the known injection laser is the high optical loss in the emitter regions, which significantly limits the optical efficiency at high pump currents.

- факторы оптического ограничения для активной области нулевой моды и моды m (m=1, 2, 3…) соответственно, оптические грани, омические контакты и оптический резонатор. Активную область образует объемный слой полупроводникового материала -GaAs, ширина запрещенной зоны которого меньше ширины запрещенной зоны волновода -Al_0,3Ga_0,7As, а толщина достигает 1200

. Повышение импульсной оптической мощности импульсного инжекционного лазера достигается за счет увеличения толщины активной области.Known pulsed injection laser (see patent RU 2361343, IPC H01S 5/32, published 10.07.2009) containing a heterogeneous structure of a separate limitation, including a multimode waveguide, the restrictive layers of which are simultaneously emitters of p- and n-type conductivity with the same refractive indices, active the region whose location in the waveguide and the thickness of the waveguide satisfy the relation

- factors of optical limitation for the active region of the zero mode and the mode m (m = 1, 2, 3 ...), respectively, optical faces, ohmic contacts and optical resonator. The active region forms a bulk layer of a GaAs semiconductor material, whose band gap is less than the band gap width of Al- _{0.3 0.3} Ga _0.7 As and the thickness reaches 1200

. An increase in the pulsed optical power of a pulsed injection laser is achieved by increasing the thickness of the active region.

.The known pulsed injection laser cannot be used with an active region based on strained quantum-size epitaxial layers. In such lasers, due to the inconsistency of the lattice parameters of the materials in the waveguide and active regions, the thickness of the active region is limited to a critical layer thickness not exceeding 100

.

Known pulsed injection laser (see patent RU 2259620, IPC H01S 5/32, published 27.08.2005), which coincides with this decision on the largest number of essential features and adopted for the prototype. The laser prototype contains a heterostructure of a separate limitation, including a multimode waveguide, the limiting layers of which are simultaneously emitters of p- and n-type conductivity with the same refractive indices, the active region consisting of at least one quantum-size active layer, whose location is the waveguide and the thickness of the waveguide satisfy the relation

- факторы оптического ограничения для активной области нулевой моды и моды m (m=1, 2, 3…) соответственно,Where

- optical limiting factors for the active region of the zero mode and the mode m (m = 1, 2, 3 ...), respectively,

, при котором моды высших порядков подавлены, а пороговое условие выполняется только для нулевой моды, внутренние оптические потери достигают низких значений, что приводит к росту оптической мощности лазерного излучения.optical faces, ohmic contacts and optical resonator. The active region is located in the additional layer, the refractive index of which is larger than the waveguide's refractive index, and the thickness and location in the waveguide are determined from the condition for the above relation to be met. The waveguide region from the emitter n-type conductivity is formed thick _commonly d ≤L _n, wherein L _n - diffusion length of electrons microns, and the distance from the active region to the emitter of p-type conductivity not greater than the diffusion length of holes in the waveguide. The emitter regions are effective injectors of nonequilibrium charge carriers into the active region and simultaneously optical limiters of laser radiation in waveguide regions. The main function of the layers of optical stops is to keep the laser radiation in the waveguide regions. By increasing the thickness of the waveguide, while maintaining the difference between the refractive indices of the waveguide and the emitters, and due to the asymmetric position of the active region in the waveguide, provided

in which higher-order modes are suppressed, and the threshold condition is satisfied only for the zero mode, the internal optical loss reaches low values, which leads to an increase in the optical power of the laser radiation.

In the pulsed generation modes of the injection laser of the prototype, in the absence of effects of thermal degradation, the current dependence of the generated power is accompanied by saturation of the intensity at the fundamental wavelength of radiation and expansion of the spectrum to the shortwave region.

The present invention was the development of a pulsed injection laser, which would have increased the maximum peak power while reducing the width of the spectrum of laser radiation.

The task is solved by the fact that a pulsed injection laser contains a heterogeneous structure of a separate limitation, including an asymmetric multimode waveguide, the limiting layers of which are simultaneously emitters of p- and n-type conductivity with the same refractive indices, the active region consisting of at least one quantum size of the active layer, optical faces, ohmic contacts and optical resonator. The waveguide region on the side of the emitter of the n-type conductivity is made with the thickness d _total ≤L _n , where L _n is the diffusion length of electrons, μm, and the location of the active region in the waveguide and the thickness of the waveguide satisfy the relation:

- факторы оптического ограничения для активной области нулевой моды и моды т (m=1, 2, 3…) соответственно. Волноводная область со стороны эмиттера n-типа проводимости состоит из двух слоев полупроводникового материала, имеющих одинаковый показатель преломления, при этом, первый слой, примыкающий к активной области, имеет уровень легирования N₁, см^-3, и толщину d₁, мкм, удовлетворяющие соотношениям:Where

- optical limiting factors for the active region of the zero mode and the mode m (m = 1, 2, 3 ...), respectively. The waveguide region on the side of the emitter of the n-type conductivity consists of two layers of semiconductor material having the same refractive index, while the first layer adjacent to the active region has a doping level of N ₁ , cm ^-3 , and a thickness d ₁ , μm, ratios:

where ε _s is the dielectric constant of the semiconductor material of the waveguide region, Ф⋅cm ^-1 ;

Δf is the lowering of the barrier of the isotype heterojunction taking into account the electric field of the space charge of positively charged donors at the interface boundary, B;

q is the electron charge, C;

V _bi is the potential barrier of the isotype heterojunction, B;

d _total - the total thickness of the waveguide region from the side of the emitter of n-type conductivity, μm;

and the second layer adjacent to the emitter has a doping level of no more than the background doping level and a thickness of d ₂ = (d _total -d ₁ ).

In the present technical solution, an increase in the maximum peak power while simultaneously reducing the width of the laser radiation spectrum in a pulsed generation mode was made possible by lowering the potential barrier at the interface waveguide-active region due to the electric field of the space charge of positively charged donors.

The dependence of the height of the energy barrier on the electric field is known and described by the Schottky effect (see S. Zi. - Physics of semiconductor devices. - T. 1, Moscow, Mir, p. 262-266, 1984).

Lowering the barrier by the value of Δf and the distance x _m, at which the potential value reaches a maximum, is determined by the relations:

where E is the magnitude of the electric field, V / cm;

The magnitude of the electric field of the space charge of positively charged donors can be calculated, for the case of an abrupt change in the concentration of impurities at the interface, as:

where V _{bi is the} value of the potential barrier of the isotype heterojunction, B;

W is the thickness of the space charge layer, see

При определении верхней границы концентрации доноров учитывали технологические возможности максимального уровня легирования квантово-размерных слоев -5⋅10¹⁸ см^-3. Вне определенного выше интервала концентраций доноров понижение потенциального барьера является незначительным, что приводит к отсутствию положительного эффекта.Using dependencies (4), (6) and (7), the lower limit of donor concentration was determined

When determining the upper limit of donor concentration, the technological capabilities of the maximum doping level of quantum-size layers -5⋅10 ¹⁸ cm ^-3 were taken into account. Beyond the range of donor concentrations defined above, the lowering of the potential barrier is insignificant, which leads to the absence of a positive effect.

Using dependencies (4) and (5), the lower limit of the thickness d _{1 of the} first layer adjacent to the active region was determined:

The maximum thickness d _{1 of the} layer is limited to 0.03⋅d _total , at which it is possible to maintain the internal optical loss at the level of 1 cm ^-1 . A further increase in the thickness d _{1 is} inexpedient, since this leads to a sharp increase in the internal optical loss and, accordingly, to a drop in the power of the outgoing radiation.

The present invention is illustrated in the drawing, where:

in fig. 1 is a schematic sectional view of a real pulsed injection laser;

in fig. 2 shows the energy diagram of the conduction band (E _c ^em is the band gap of the emitter of the n-type conductivity, eV; E _C ^OCL is the band gap of the waveguide region, eV; E _C ^QW is the band gap of the active region, eV);

in fig. 3 shows the doping profile of the interface boundary of the waveguide region on the side of a wide-gap n-type emitter and active region of a pulsed semiconductor laser (N is the doping amount, cm ^-3 ; d ^QW is the active region thickness, μm.).

A pulsed injection laser (see Fig. 1) generally includes the following elements: n-type electrical conductivity substrate 1, on the one hand there is an ohmic contact 2, and on the other side of the substrate a heterostructure is formed, comprising: an doped dopant layer 3 optical confinement (wide-gap emitter n-type conductivity), intentionally not doped layer 4 of thickness d ₂ of the waveguide region adjacent to the emitter layer 3, n-type conductivity layer of thickness d ₁ 5 is doped to the level N1, quantum-sized intentionally n doped layer of the active region 6, intentionally undoped doped layer 7 of the waveguide region adjacent to the p-type emitter 8 (optical limiting layer) doped with p-type impurity, contact layer 9 doped with p-type impurity, ohmic contact 10. On cleaved face 11 is coated with antireflection (reflection coefficient R = 5%) dielectric coatings 12; reflective (R = 95%) dielectric coatings 14 are applied to the cleaved edge 13. The edges 11 and 13 form a Fabry-Perot resonator.

Pulsed injection laser operates as follows. A pulsed electric current is passed through the ohmic contacts 2 and 10, and the operating mode of the injection laser (laser diode) corresponds to the forward displacement of the pn junction. To suppress overheating of the active region, the pulse duration is less than 100 ns, and the frequency is less than 10 kHz. When the threshold value of the current passed through the injection laser is exceeded, laser radiation is emitted through the anti-reflective coating 12 applied to face 11. The power of the outgoing radiation, in addition to the parameters of the structure, depends on the magnitude of the current transmitted through the laser heterostructure.

с шириной запрещенной зоны 1,21 эВ (показатель преломления n=3,64), волноводные слои - из твердого раствора Al₀,₃Ga_0,7As (n=3,419), эмиттерные слои - из твердого раствора Al_0,5Ga_0,5As (n=3,34). Была выбрана предварительная толщина волноводной области 1,7 мкм (на основании требований к волноводу - он должен быть многомодовый на основании решения волнового уравнения). Для Al₀,₃Ga_0,7As волновода с концентрацией электронов n=10¹⁵ см^-3 длина диффузии электронов - L_n=9 мкм и дырок - L_p=2 мкм. Для выбранных значений параметров лазерной гетероструктуры для разных положений активной области в волноводе решалось волновое уравнение. Из найденных решений были получены распределения полей для всех мод. На основании полученных распределений были определены значения факторов оптического ограничения активной области для всех мод в каждом из возможных положений дополнительного слоя. Из полученных зависимостей было определено, что в случае, когда активная область (ее центр) расположена на расстоянии 1,3 мкм от широкозонного эмиттера n-типа и, соответственно, на расстоянии 0,4 мкм от широкозонного эмиттера р-типа электропроводности, неравенство

выполняется, и эти расстояния меньше длины диффузии дырок и электронов. Таким образом, имеем следующую конструкцию лазерной гетероструктуры: подложка из GaAs, легированная примесью n-типа, с одной стороны которой расположен легированный кремнием до степени N=10¹⁸ см^-3 n-типа слой оптического ограничения, выполненный из твердого раствора Al_0,5Ga_0,5As толщиной 2 мкм. Далее расположены слои волноводной области, выполненной из Al_0,3Ga_0,7As толщиной d₂=1,3 мкм и d₁=70

с концентрацией легирования N=10¹⁵ см^-3 и N₁=4⋅10¹⁸ см^-3, соответственно, далее располжена активная область, выполненная из In_0,3Ga_0,7As толщиной 100

с концентрацией легирования N=10¹⁵ см^-3, далее расположен слой волноводной области, выполненной из Al_0,3Ga_0,7As толщиной 0,4 мкм с концентрацией легирования N=10¹⁵ см^-3, далее расположены: легированный магнием до степени Р=10¹⁸ см^-3 р-слой оптического ограничения, выполненный из твердого раствора Al_0,3Ga_0,5As толщиной 2 мкм, контактный слой, выполненный из GaAs толщиной 0,2 мкм, легированный магнием до степени Р=10¹⁸ см^-3, и омический контакт. На одну из сколотых граней нанесены просветляющие (слои SiO₂, R=5%) диэлектрические покрытия, на противоположную сколотую грань нанесены отражающие (три пары слоев из SiO₂+Si, R=95%) диэлектрические покрытия. Ширина омических контактов составляет 100 мкм. Длина резонатора Фабри-Перо (расстояние между оптическими гранями) составляет 3 мм. Для такого лазерного диода в импульсном режиме генерации при плотности тока J=50 кА/см² (длительность импульса 100нс, а частота 10кГц) мощность излучения достигает 119 Вт, ширина спектра излучения составляет 10 нм, что свидетельствует о двукратном увеличении абсолютного значения мощности и более чем шестикратном увеличении мощности на основной длине волны излучения по сравнению с лазерами, выполненными на основе конструкции, взятой за прототип.Example 1. The following compositions of the heterostructure layers were selected as the base (based on the selected radiation wavelength λ = 1002 nm) The active region was made of an In5 layer of _0.35 Ga _0.65 As with a thickness of 100

with a band gap of 1.21 eV (refractive index n = 3.64), waveguide layers from Al ₀ , ₃ Ga _0.7 As solid solution (n = 3.419), emitter layers from Al _0.5 Ga solid solution _0.5 As (n = 3.34). A preliminary thickness of the waveguide region of 1.7 μm was chosen (based on the requirements for the waveguide - it should be multimode based on the solution of the wave equation). For Al ₀ , ₃ Ga _0.7 As a waveguide with an electron concentration of n = 10 ¹⁵ cm ^{-3 the} length of the diffusion of electrons - L _n = 9 μm and holes - L _p = 2 μm. For selected values of the parameters of the laser heterostructure, the wave equation was solved for different positions of the active region in the waveguide. From the solutions found, field distributions were obtained for all modes. Based on the obtained distributions, the values of the optical limitation factors of the active region were determined for all modes in each of the possible positions of the additional layer. From the obtained dependencies, it was determined that in the case when the active region (its center) is located at a distance of 1.3 μm from the n-type wide-gap emitter and, accordingly, at a distance of 0.4 μm from the wide-gap emitter of the p-type conductivity, the inequality

is fulfilled, and these distances are less than the diffusion length of holes and electrons. Thus, we have the following laser heterostructure design: a GaAs substrate doped with an n-type impurity, on one side of which a silicon-doped optical confinement layer is located to the degree N = 10 ¹⁸ cm ^-3 , made of Al _0.5 solid solution Ga _0.5 As 2 microns thick. Next are the layers of the waveguide region, made of Al _0.3 Ga _0.7 As thick d ₂ = 1.3 μm and d ₁ = 70

with a doping concentration of N = 10 ¹⁵ cm ^-3 and N ₁ = 4⋅10 ¹⁸ cm ^-3 , respectively, then the active region made of In _0.3 Ga _0.7 As thick 100 thick

with a doping concentration of N = 10 ¹⁵ cm ^-3 , then a waveguide region layer is made of Al _0.3 Ga _0.7 As thick 0.4 μm with a doping concentration N = 10 ¹⁵ cm ^-3 , then there are: magnesium doped to degree P = 10 ¹⁸ cm ^-3 p-optical limiting layer made of Al _0.3 Ga _0.5 As solid solution 2 μm thick, contact layer made of 0.2 μm GaAs doped with magnesium to P = 10 ¹⁸ cm ^-3 , and ohmic contact. Anti-reflective (SiO ₂ layers, R = 5%) dielectric coatings are deposited on one of the cleaved faces, and reflective (three pairs of layers of SiO ₂ + Si, R = 95%) dielectric coatings are applied to the opposite cleaved face. The width of the ohmic contacts is 100 µm. The length of the Fabry-Perot cavity (the distance between the optical faces) is 3 mm. For such a laser diode in a pulsed generation mode with a current density of J = 50 kA / cm ² (pulse duration 100 ns and frequency 10 kHz), the radiation power reaches 119 W, the width of the emission spectrum is 10 nm, which indicates a twofold increase in the absolute value of power and more than a sixfold increase in power at the fundamental wavelength of radiation compared with lasers, made on the basis of the design, taken as a prototype.

с шириной запрещенной зоны 0,830 эВ (n=3,96), волноводные слои - из твердого раствора Al₀,₂Ga_0,35In_0,45As (n=3,72), эмиттерные слои - из твердого раствора InP (n=3,22). Была выбрана предварительная толщина волноводной области 1,7 мкм (на основании требований к волноводу - он должен быть многомодовым на основании решения волнового уравнения). Для выбранных значений параметров лазерной гетероструктуры для разных положений активной области в волноводе решалось волновое уравнение. Из найденных решений были получены распределения полей для всех мод. Из полученных зависимостей было определено, что в случае, когда активная область (ее центр) расположена на расстоянии 1,3 мкм от широкозонного эмиттера n-типа и, соответственно, на расстоянии 0,4 мкм от широкозонного эмиттера р-типа электропроводности, неравенство

выполняется, и эти расстояния меньше длины диффузии дырок и электронов. Таким образом, имеем следующую конструкцию лазерной гетероструктуры: подложка из InP, легированная примесью n-типа, на которой последовательно расположены легированный кремнием до степени N=10¹⁸ см^-3 n-типа слой InP оптического ограничения толщиной 2 мкм, далее расположены слои волноводной области, выполненной из раствора Al₀,₂Ga_0,35In_0,45As, толщиной d₂ = 1.3 мкм и d₁ = 100

с концентрацией легирования N=10¹⁵см^-3 и N₁=3⋅10¹⁸ см^-3, соответственно, далее расположена активная область, выполненная из Al_0,2Ga_0,7In_0,1As толщиной 100

с концентрацией N=10¹⁵ см^-3, затем слой волноводной области, примыкающей к эмиттеру р-типа проводимости, выполненной из Al₀,₂Ga_0,35In_0,45As толщиной 0,4 мкм с концентрацией легирования N=10¹⁵ см^-3, далее расположены: легированный цинком до степени Р=10¹⁸ см^-3 р-слой оптического ограничения, выполненный из InP толщиной 2 мкм, контактный слой, выполненный из InGaAs толщиной 0,3 мкм, легированный магнием до степени Р=10¹⁸ см^-3, и омический контакт. На одну из сколотых граней нанесены просветляющие (слои SiO₂, R=5%) диэлектрические покрытия, на противоположную сколотую грань нанесены отражающие (три пары слоев из SiO₂+Si, R=95%) диэлектрические покрытия. Ширина омических контактов составляла 100 мкм. Длина резонатора Фабри-Перо (расстояние между оптическими гранями) составляло 3 мм. Для такого лазерного диода в импульсном режиме генерации при плотности тока J=10 кА/см² (длительность импульса 100 нc, а частота 10 кГц) мощность излучения достигала 20 Вт, ширина спектра излучения составляла 28 нм, что свидетельствует о трехкратном увеличении абсолютного значения мощности и более чем десятикратном увеличении мощности на основной длине волны излучения по сравнению с лазерами, выполненными на основе конструкции, взятой за прототип.Example 2. The following compositions of the heterostructure layers were selected as the base ones (based on the selected wavelength of radiation λ = 1500 nm): the active region was made of an Al _0.2 Ga _{0.7 0.7} In _0.1 As layer with a thickness of 100

a bandgap 0.830 eV (n = 3,96), the waveguide layers - Al solid solution of _{0, 2} Ga _0.35 In _0.45 As (n = 3.72), the emitter layers - of a solid solution InP (n = 3.22). A preliminary thickness of the waveguide region of 1.7 μm was chosen (based on the requirements for the waveguide - it should be multimode based on the solution of the wave equation). For selected values of the parameters of the laser heterostructure, the wave equation was solved for different positions of the active region in the waveguide. From the solutions found, field distributions were obtained for all modes. From the obtained dependencies, it was determined that in the case when the active region (its center) is located at a distance of 1.3 μm from the n-type wide-gap emitter and, accordingly, at a distance of 0.4 μm from the wide-gap emitter of the p-type conductivity, the inequality

is fulfilled, and these distances are less than the diffusion length of holes and electrons. Thus, we have the following design of a laser heterostructure: an InP substrate doped with an n-type impurity, on which silicon-doped InP optical limiting layer 2 microns thick are successively located on a silicon-doped layer to the degree N = 10 ¹⁸ cm ^-3; , made from a solution of Al ₀ , ₂ Ga _0.35 In _0.45 As, thickness d ₂ = 1.3 μm and d ₁ = 100

with a doping concentration of N = 10 ¹⁵ cm ^-3 and N ₁ = 3 см 10 ¹⁸ cm ^-3 , respectively, the active region is next made of Al _0.2 Ga _0.7 In _0.1 As with a thickness of 100

with a concentration of N = 10 ¹⁵ cm ^-3 , then a layer of the waveguide region adjacent to the emitter of p-type conductivity, made of Al ₀ , ₂ Ga _0.35 In _0.45 As with a thickness of 0.4 μm with a concentration of doping N = 10 ¹⁵ cm ^-3 , then located: doped with zinc to the degree P = 10 ¹⁸ cm ^-3 p-layer of optical confinement, made of InP 2 μm thick, contact layer made of InGaAs 0.3 μm thick, doped with magnesium to P = 10 ¹⁸ cm ^-3 , and ohmic contact. Anti-reflective (SiO ₂ layers, R = 5%) dielectric coatings are deposited on one of the cleaved faces, and reflective (three pairs of layers of SiO ₂ + Si, R = 95%) dielectric coatings are applied to the opposite cleaved face. The width of the ohmic contacts was 100 μm. The length of the Fabry-Perot cavity (the distance between the optical faces) was 3 mm. For such a laser diode in a pulsed generation mode with a current density of J = 10 kA / cm ² (pulse duration 100 ns and frequency 10 kHz), the radiation power reached 20 W, the emission spectrum width was 28 nm, which indicates a threefold increase in the absolute power value and more than a tenfold increase in power at the main wavelength of radiation compared with lasers, made on the basis of the design, taken as a prototype.

Claims (11)

Pulsed injection laser containing a heterogeneous structure of a separate limitation, including an asymmetric multimode waveguide, whose restrictive layers are simultaneously emitters of p- and n-type conductivity with the same refractive indices, an active region consisting of at least one quantum-size active layer, optical faces, ohmic contacts and an optical resonator; the waveguide region on the emitter side of n-type conductivity is made of thickness d _total ≤L _n , where L _n is the diffusion length of el electrons, μm, and the location of the active region in the waveguide and the thickness of the waveguide satisfy the relation:

Where

- optical limiting factors for the active region of the zero mode and the mode m ( m = 1, 2, 3 ...), respectively, characterized in that the waveguide region from the side of the emitter of the n-type conductivity consists of two layers of semiconductor material having the same refractive index, while the first layer adjacent to the active region has the doping level N _l , cm ^-3 , and the thickness d _l , μm, satisfying ratios:

(2ε _s ⋅ V _bi / q ¹ N1) ^1/2 ≤ d _l ≤ 0.03 d _total ; where ε _s is the dielectric constant of the semiconductor material of the waveguide region, Ф⋅cm ^-1 ; Δφ — reduction of the isotype heterojunction barrier with allowance for the electric field of the space charge of positively charged donors at the interface boundary, B; q is the electron charge, C; V _bi is the potential barrier of the isotype heterojunction, B; and the second layer, adjacent to the emitter, has a doping level of no more than the background doping level and a thickness of d ₂ = (d _common –d ₁ ).

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