RU2444101C1 - Injection laser - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: heterostructure-based laser has a waveguide layer enclosed between wide-gap emitters with p and n conductivity type, which are simultaneously bounding layers, an active region consisting of quantum size active layer, an optical Fabry-Perot resonator and a strip ohmic contact with an injection region underneath. In the waveguide layer outside the injection region there is a doped region, where the optical limiting factor of the closed mode in the doped region and concentration of free charge carriers in the doped region satisfy the relationship:

where:

is the value of the component of the optical limiting factor G_Y in the amplification region for the closed mode, arbitrary units;

is the mode loss at the output of the Fabry-Perot resonator, cm^-1; α_i is loss due to absorption on free charge carriers in the amplification region, cm^-1; Δα denotes losses associated with closed mode radiation scattering on irregularities (α_SC), inter-band absorption (α_BGL) and absorption on free charge carriers in lateral parts of the injection laser, cm^-1;

is the closed mode optical limiting factor in the doped region, arbitrary units; n, p denote concentration of free electrons and holes in the doped region, respectively, cm^-3; σ_n, σ_p denote the absorption cross-section on free electrons and holes in the doped region, respectively, cm².

EFFECT: high optical power output in both continuous and pulsed modes of current pumping, high stability of the output optical power.

13 cl, 5 dwg

Description

The present invention relates to quantum electronic technology, and more specifically to high-power semiconductor lasers.

Powerful semiconductor lasers are widely used in many fields of science and technology, for example, they are used as a source of optical radiation for pumping fiber amplifiers, fiber and solid-state lasers. This requires a semiconductor laser to combine maximum efficiency and radiation power. The development of new approaches to the design of high-power semiconductor lasers has significantly improved the optical parameters of heterostructures. For modern semiconductor lasers, the internal optical loss is less than 1 cm ^-1 with an internal quantum yield close to 100%. The high optical perfection of laser heterostructures and low optical losses make it possible to achieve continuous and pulsed excitation levels of several tens of amperes. The consequence of such changes in the characteristics of laser heterostructures and excitation levels is the emergence of new effects, a number of which lead to saturation of the watt-ampere characteristic and a decrease in the maximum output radiation power.

Known injection laser (see patent US 7643527, IPC H05S 5/323, published 05.01.2010), including a substrate, characterized by the presence of regions with dislocations with a density of 10 ⁵ cm ^-2 or more, a crystalline semiconductor structure located on the substrate and having an active layer. The insulating layer is located on the semiconductor structure, the upper ohmic contact is located on the insulating layer and is electrically connected to the semiconductor structure to inject current into the active region. The lower ohmic contact is located on the lower surface of the substrate. The semiconductor laser has an optical resonator with a length L and an upper ohmic contact area of 120 · L μm ² or less.

The disadvantages of the proposed injection laser include the lack of technical solutions to suppress the generation of a closed mode. As a result, the output optical power of the proposed semiconductor laser does not reach the maximum possible value.

An injection laser is known (see patent RU No. 2230410, IPC H01S 5/042, published June 10, 2004), which includes a laser heterostructure with waveguide layers, in one of the limiting layers of which there are relief structures, at least part of the mesa strip and passive regions with bases near the boundary of the boundary layer closest to the active region. At least a portion of the base of each passive region is a relief structure adjacent to the messtrip, having in the direction perpendicular to the longitudinal axis of the resonator a length exceeding the distance providing scattering of radiation propagating in said direction perpendicular to the longitudinal axis of the resonator. Each relief structure has an amplitude of at least 0.1 μm and is distant from the mentioned boundary of the bounding layer by a distance not exceeding 0.5 μm.

The known laser has an increased output radiation power, a narrowed and improved spatial diagram of the output radiation in the p-n junction plane to a single-mode, an improved emission spectrum to a single-frequency, as well as stable parameters due to an increase in the absorption efficiency of undesirable high-order and ring modes, and optimization of the lateral optical limitation.

However, the well-known injection laser does not solve the problem of increasing the optical power, since laser heterostructures with low internal optical losses are characterized by a localization of the laser mode field close to 100% in the waveguide layers. In this case, any periodic structures formed in any restrictive layers become ineffective, because the laser mode field does not overlap with them.

Known injection laser (see No. 2230411, IPC H01S 5/034, published 06/10/2004), comprising a heterostructure containing an active layer, at least waveguide layers, boundary layers placed on both sides of it, as well as a mestripe of comb-like waveguide, formed from the p-type side of the heterostructure, with the base located in the bounding layer placed on the same side of the active layer. The boundary layer on the p-type side of the heterostructure is formed of at least two sublayers having the same composition. The restrictive first sublayer adjacent to the waveguide layer is either not doped or has a p-type concentration of not more than 3 · 10 ¹⁷ cm ^-3 . The next limiting sublayer adjacent to the first one has a p-type concentration of more than 3 · 10 ¹⁷ cm ^-3 , the messtrip of the crest-shaped waveguide is formed in two layers. The first tier is coaxially located on the second tier of the mesa strip additionally inserted into the restrictive first sublayer, having a width exceeding the width of the first tier of the mesa strip by 1.5-4 times.

In the known laser, a decrease in the series resistance of the laser is ensured with a minimum spreading profile, as well as stabilization of the single-mode lasing mode.

A disadvantage of the known laser is the presence of optical communication with the regions lateral relative to the mesa strip. The absence of additional technical solutions that increase the internal optical loss in the side regions leads to the fulfillment of the threshold conditions for the generation of closed modes and a decrease in the output optical power.

The closest in technical essence and in the aggregate of essential features is an injection laser (see patent RU No. 2259620, IPC H01S 5/32, published August 27, 2005). The injection laser prototype contains a separate confinement heterostructure, including a multimode waveguide, the confining layers of which are simultaneously emitters of p- and n-type conductivity with the same refractive indices, an active region consisting of at least one quantum-dimensional active layer, the location of which in the waveguide and the thickness of the waveguide satisfy the relation

G ⁰ _QW / G ^m _QW >1.7;

where Г ⁰ _QW and Г ^m _QW are the optical confinement factors for the active region of the zero mode and mode m (m = 1, 2, 3 ...), respectively. The injection laser also contains reflectors, optical faces, ohmic contacts and an optical resonator. The active region is placed in an additional layer, the refractive index of which is greater than the refractive index of the waveguide, and the thickness and location in the waveguide are determined from the condition for the above relation to be fulfilled, and the distances from the active region to p- and n-emitters do not exceed the diffusion lengths of holes and electrons in the waveguide, respectively .

The known injection laser has a small divergence of radiation while maintaining a high value of efficiency and output power of the radiation.

A disadvantage of the known laser is the presence of optical communication with the regions lateral relative to the mesa strip. The absence of additional technical solutions in the injection laser prototype that increase the internal optical loss in the side regions leads to the fulfillment of the threshold conditions for the generation of closed modes and a decrease in the output optical power.

The objective of the proposed technical solution was the development of such an injection laser design that would provide an increase in the output optical power in both continuous and pulsed current pumping modes, and increase the temporal stability of the output optical power.

The problem is solved in that the injection laser based on the heterostructure includes a first waveguide layer enclosed between wide-gap p- and n-type emitters, which are simultaneously boundary layers, an active region consisting of at least one quantum-dimensional active layer, optical Fabry-Perot resonator and strip ohmic contact, under which the injection region is located. At least one doped region is formed in at least the first waveguide layer outside the injection region. The optical limitation factor of the closed mode (ZM) in the doped region and the concentration of free charge carriers in the doped region satisfy the relation:

;

;

- значение составляющей фактора оптического ограничения Г_Y в области усиления для ЗМ, отн. ед.;Where

- the value of the constituent factor of the optical limitation G _Y in the amplification region for ZM, rel. units;

- потери на выход Фабри-Перо моды, см^-1;

- losses at the exit of the Fabry-Perot fashion, cm ^-1 ;

α _i - internal optical absorption loss on free charge carriers in the amplification region, cm ^-1 ;

Δα is the optical loss associated with the scattering of ZM radiation by inhomogeneities (α _SC ), interband absorption (α _BGL ) and absorption on free charge carriers in the sides of the injection laser relative to the strip ohmic contact, cm ^-1 ;

- фактор оптического ограничения ЗМ в легированной области, отн. ед.;

- factor of optical limitation of ZM in the doped region, rel. units;

σ _n is the absorption cross section for free electrons in the doped region, cm ² ;

n is the concentration of free electrons in the doped region, cm ^-3 ;

σ _p is the absorption cross section for free holes in the doped region, cm ² ;

p is the concentration of free holes in the doped region, cm ^-3 .

The distance between the nearest boundaries of the doped region and the injection region can be no less than 10 μm, and its width not less than 10 μm.

The doped region may contain an element selected from the group: Si, Te, Ge, Sn, or a combination thereof as an n-type dopant.

The doped region may contain an element selected from the group C, S, Mg, Be, Zn, or a combination of these as a p-type dopant.

The doped region can be formed by ion bombardment.

The doped region can be formed by diffusion of the impurity from the surface layers into the waveguide layer.

At least in the first waveguide layer, two doped regions located in the side parts of the injection laser can be made outside the injection region.

The concentration of the dopant of each type can be not less than 10 ¹⁷ cm ^-3 .

The injection laser may comprise a second waveguide layer with a band gap smaller than the band gap of the first waveguide layer, the active region being located in the second waveguide layer.

In an injection laser, the longitudinal size of the doped region can be less than the length of the optical Fabry-Perot resonator.

The heterostructure of the injection laser can be performed in the system of solid solutions A ³ B ⁵ .

Improving the output characteristics of the inventive injection laser is provided by suppressing the generation of ZM.

The inventive injection laser is illustrated in the drawing, where

figure 1 shows a well-known injection laser with a strip ohmic contact;

figure 2 shows the inventive injection laser, in the side of which a doped region is introduced;

figure 3 shows the inventive injection laser with the first and second waveguide layers.

, и

- материальное усиление соответственно ФПМ и ЗМ,

и

- потери на межзонное поглощение в пассивных областях соответственно для ФПМ и ЗМ);figure 4 shows the qualitative dependence of the material gain in the active strip (curve 1) and losses in the passive region (curve 2) on the wavelength (λ _FP and λ _CM are the generation wavelengths, respectively, of the FPM and ZM,

, and

- material gain, respectively, FPM and ZM,

and

- losses due to interband absorption in the passive regions for the MTF and ZM, respectively);

figure 5 shows the dependence of the output optical power exiting through the face coated with an antireflection coating on the pump current for a known injection laser and the inventive injection laser (curve 3 for continuous pump current, curve 4 for pulsed pump current for a known laser; curve 5. - with a continuous pump current, curve 6 - with a pulsed pump current for the inventive injection laser).

The known injection laser (see Fig. 1) contains a first waveguide layer 1, enclosed between a wide-band p-type emitter 2 and a wide-band n-type emitter 3, an active region 4 consisting of at least one quantum-dimensional active layer, an optical Fabry-Perot resonator, formed naturally by a cleaved face 5 with a coated antireflection and a face 6 with a reflective coating, a strip ohmic contact 7, under which there is an injection region 8, including a gain region (behind trihovana inclined solid lines) 9, side naturally cleaved facets forming the lateral limiting surface 10, substrate 11, the side portions of the injection laser (shaded inclined broken lines) 12.

The proposed injection laser (see figure 2) contains the first waveguide layer 1, enclosed between a wide-band p-type emitter 2 and a wide-band n-type emitter 3, an active region 4 consisting of at least one quantum-dimensional active layer, an optical Fabry-Perot resonator, formed naturally by a cleaved face 5 with a coated antireflection and a face 6 with a coated reflective stripe ohmic contact 7, under which there is an injection region 8, including a gain region (shaded by inclined continuous lines) 9, laterally naturally cleaved faces forming lateral boundary surfaces 10, substrate 11, side parts of the injection laser (shaded by oblique broken lines) 12, doped region (shaded by straight vertical lines) 13. The injection laser may contain two doped regions 13 located in the lateral parts of the injection laser. The distance between the nearest boundaries of the doped region 13 and the injection region 8 can be no less than 10 μm, and its width not less than 10 μm. The doped region 13 may contain as an dopant of n-type conductivity an element selected from the group: Si, Te, Ge, Sn, or a combination thereof. In another embodiment of the invention, the doped region 13 may contain, as a p-type dopant, an element selected from the group: C, S, Mg, Be, Zn, or a combination thereof. The doped region 13 can be formed, for example, by ion bombardment or by diffusion of the impurity from the surface layers into the first waveguide layer 1. The concentration of the dopant of each type can be no less than 10 ¹⁷ cm ⁻³ . The injection laser may comprise a second waveguide layer 14 (see FIG. 3) with a band gap smaller than the band gap of the first waveguide layer 1, while the active region 4 is located in the second waveguide layer 14. The longitudinal dimension of the doped region 13 may be less than the length Optical Fabry-Perot resonator. The heterostructure of the injection laser can be performed in the system of solid solutions A ³ B ⁵ .

Improving the output characteristics of the inventive injection laser is provided by suppressing the generation of ZM. Injection lasers are characterized by a mode radiation structure, which is calculated using the wave equation [H. Casey, M. Panish. - Lasers on heterostructures. - Moscow, Mir, 1981; L.A. Coldren, S.W. Corzine. - Diode lasers and photonic integrated circuits. (N.Y., John Wiley & Sons, 1995)]. Two types of mod structures can be distinguished. The first is the Fabry-Perot resonator (FPM) mode. Such modes are characterized by the propagation of radiation along the optical axis of the resonator at angles normal to the Fabry-Perot mirrors of the resonator (naturally, the cleaved face 5 with the antireflection coating and face 6 with the applied reflective coating) are smaller than the angle of total internal reflection. As a result, the PMF is characterized by nonzero losses on the output of radiation from the resonator. It is this radiation that is useful when using injection lasers as sources of optical radiation. The structures of the Fabry-Perot resonator modes are determined by the waveguides formed by the first waveguide and emitter (restrictive) layers of the heterostructure (1, 2, 3), the ohmic strip contact 7, and the Fabry-Perot cavity mirrors (5, 6). The second type of mod structure is ZM. Such modes are characterized by the propagation of radiation at angles to the normals relative to the Fabry-Perot mirror mirrors (5, 6) of the resonator and the lateral limiting surfaces 10 larger than the angle of total internal reflection. As a result, ZM is characterized by zero losses in the output of radiation from the resonator. ZM structures are determined by waveguides formed by waveguide and emitter (restrictive) layers of the heterostructure, a strip ohmic contact, Fabry-Perot mirrors of the resonator, and lateral boundary surfaces. The fulfillment of the threshold generation conditions for the FPM or ZM determines the operation mode of the injection laser. When the generation threshold is fulfilled only for the FPM, the maximum useful output efficiency is achieved and, accordingly, the output optical power increases. When the threshold generation conditions for the ZM are fulfilled, part of the laser radiation does not go outside and remains inside the injection laser, as a result, a partial or complete drop in the output optical power and a decrease in efficiency occur. In an injection laser, the threshold for laser mode generation is achieved when two conditions are satisfied: the modal gain is equal to the total optical loss and feedback is present. The first condition is satisfied due to the injection current flowing through the strip ohmic contact 7 and creating an inverse population by charge carriers of the active region 4 under the strip ohmic contact 7. Thus, in the active region 4 under the strip ohmic contact 7, conditions are created for amplification of optical radiation, and this part of the active region 4 is called the amplification region 9. For the lateral parts of the active region 4 relative to the strip ohmic contact 7, the conditions for amplification are not created, because they are electrically isolated from the injection current. However, there remains an optical connection between the lateral parts of the active region 4 and the amplification region 9 through a common first waveguide layer 1. The second condition for injection lasers is satisfied by a resonator formed by naturally cleaved faces. Naturally cleaved faces form two types of resonators: the Fabry-Perot resonator is formed by two mirrors 5, 6 — parallel cleaved faces, the ZM resonator is formed by four cleaved faces (faces — mirrors 5, 6 and their orthogonal faces — lateral limiting surfaces 10), which limit the injection laser and the resulting in the manufacture of an injection laser by splitting the heterostructure. In general terms, the threshold generation condition can be written as [L.A. Coldren, S.W. Corzine. - Diode lasers and photonic integrated circuits. (N.Y., John Wiley & Sons, 1995)]:

where G _mod is the modal gain created by the charge carriers injected into the active region 4, α _i are the internal optical losses in the gain region 9, and α _out are the losses associated with the exit of laser radiation from the cavity. Modal gain is expressed in terms of material gain (g _mat ), calculated through the concentration of 4 charge carriers injected into the active region [LAColdren, SWCorzine. - Diode lasers and photonic integrated circuits. (NY, John Wiley & Sons, 1995)], and the optical mode confinement factor (G) in gain region 9:

In general, the optical confinement factor in the amplification region determines the fraction of the laser mode energy attributable to this region and is expressed through the electric field of the injection laser mode E (x, y, z) [L.A. Coldren, S.W. Corzine. - Diode lasers and photonic integrated circuits. (N.Y., John Wiley & Sons, 1995)]

where Vg is the volume of the amplification region 9, Vm is the volume of the injection laser. The fashion field is described as a product of [L.A. Coldren, S.W. Corzine. - Diode lasers and photonic integrated circuits. (N.Y., John Wiley & Sons, 1995)]

The optical mode confinement factor in the gain region 9 of the injection laser is expressed through three independent components of the optical mode confinement factor in the gain region 9 _X , G _Y , and G _Z (see FIG. 1).

In an injection laser with a strip ohmic contact 7, the width of the strip ohmic contact (w) exceeds the generation wavelength, and the Fabry-Perot mirror mirrors (5, 6) limit the gain region in the direction parallel to the cavity axis. This allows the FPM field to be completely localized in the region limited by the dimensions of the strip ohmic contact and the length of the resonator. This means for the FPM Г _Y = 1 and Г _Z = 1. FPM electromagnetic waves propagate along the Fabry-Perot axis of the resonator at angles smaller than the angle of total internal reflection relative to the normal to the Fabry-Perot mirror mirrors (5, 6) and are characterized by the outgoing radiation loss α _out . The component of the optical limiting factor Г _{X is the} same for the ZM and FPM and depends on the design of the laser heterostructure: the composition and thickness of the first waveguide and restrictive layers (1, 2, 3), as well as the thickness of the active region 4. For laser heterostructures, Г _X is an optical mode factor transverse waveguide in the active region of 4 G _QW . Then the threshold generation condition (1) for the MTF can be rewritten as

- материальное усиление на длине волны генерации ФПМ;Where

- material gain at the FPM generation wavelength;

- потери на выход ФПМ;

- loss on the exit of the FPM;

α _i - internal optical loss associated with absorption on free charge carriers.

на длине волны генерации λ_FP соответствует достаточно высокое значение потерь на межзонное поглощение в пассивных областях

. Как следствие, область распространения ФПМ ограничена только областью под полосковым омическим контактом. Из фиг.4 видно, что смещение в длинноволновую область спектра относительно длины волны генерации ФПМ одновременно ведет к снижению материального усиления в активной области 4 и падению значения оптических потерь (α_BGL) в боковых областях относительно полоскового омического контакта 7. Таким образом, вследствие нулевых потерь на выход для ЗМ даже в условиях меньшего значения материального усиления

на длине волны генерации для ЗМ может быть достигнут порог генерации. Рассмотрим пороговое условие генерации для ЗМ в инжекционном лазере с полосковым омическим контактом 7. Так как ЗМ захватывает весь объем первого волноводного слоя 1 инжекционного лазера, то фактор оптического ограничения ЗМ для области усиления (Г_CM) выглядит следующим образомIn order to determine the threshold generation condition for the ZM, it is necessary to evaluate the conditions of its propagation in the injection laser. Unlike the FPM, the electromagnetic waves of the SM propagate at angles greater than the angle of total internal reflection relative to the normal to the lateral limiting surfaces 10 and the Fabry-Perot cavity mirrors (5, 6). ZM is characterized by zero loss on the output of radiation from the resonator. In [S.O. Slipchenko, D. A. Vinokurov, A. V. Lyutetskiy, N. A. Pikhtin, A. L. Stankevich, N. V. Fetisova, A. D. Bondarev, I. S. Tarasov. - FTP, 43, 1409 (2009)] it was experimentally shown that, unlike the FPM, the ZM captures the entire volume of the injection laser, including the side parts relative to the strip contact 7. Figure 4 shows the qualitative dependences on the wavelength of the material gain in the amplification region 9 under the strip ohmic contact 7 (g _mat ) and from optical loss (α _BGL ) in the side regions relative to the strip ohmic contact. MTF with the maximum value of material gain

at the generation wavelength λ _FP corresponds to a fairly high value of the loss in interband absorption in the passive regions

. As a result, the region of propagation of the FMP is limited only to the region under the strip ohmic contact. Figure 4 shows that the shift to the long-wavelength region of the spectrum relative to the FPM generation wavelength simultaneously leads to a decrease in material gain in the active region 4 and a decrease in the optical loss (α _BGL ) in the side regions relative to the strip ohmic contact 7. Thus, due to the zero output losses for ZM even in the conditions of a lower value of material gain

at the generation wavelength for ZM, the generation threshold can be reached. Let us consider the threshold generation condition for the ZM in the injection laser with a strip ohmic contact 7. Since the ZM captures the entire volume of the first waveguide layer 1 of the injection laser, the optical limitation factor of the ZM for the gain region (Г _CM ) is as follows

- значение составляющей фактора оптического ограничения Г_Y в области 9 усиления для ЗМ. Как показано выше (и подтверждено экспериментально), длина λ_CM волны генерации ЗМ смещена в низкоэнергетическую область спектра относительно ФПМ. В результате материальное усиление ЗМ (

) может быть представлено как:Where

- the value of the constituent factor of the optical limitation G _Y in the amplification region 9 for ZM. As shown above (and confirmed experimentally), the length λ _CM of the ZM generation wave is shifted to the low-energy region of the spectrum relative to the MTF. As a result, material amplification of ZM (

) can be represented as:

where Δ is the detuning of material amplification, defined as the difference between the material amplifications of the FPM and ZM. Optical loss for ZM α _CM can be expressed as:

the quantity Δα takes into account losses associated with the scattering of ZM radiation by inhomogeneities, interband absorption, and absorption by free charge carriers in the side parts of the injection laser relative to the strip ohmic contact 7. Since the optical loss to the radiation output for ZM is zero, then in expression (9) they are not taken into account.

Based on the foregoing, the threshold conditions for ZM will take the form:

Taking the value Δ = 0, taking into account (3), we obtain an inequality, the satisfaction of which suppresses the generation of ZMs in known injection lasers

. Увеличение потерь для ЗМ до величин, при которых выполняется указанное неравенство, позволяет подавить генерацию ЗМ в заявляемом инжекционном лазере. Требуемая для подавления генерации ЗМ величина внутренних оптических потерь в созданной легированной области 13 подбирается путем выбора ее размеров и положения, решая волновое уравнение, что определяет значение

, а также путем выбора концентрации и типа легирующей примеси.At least one doped region 13 created at least in the first waveguide layer 1 outside the injection region 8 can increase the optical loss for ZM by

. The increase in losses for ZM to values at which the specified inequality is satisfied, allows to suppress the generation of ZM in the inventive injection laser. The amount of internal optical loss required to suppress the generation of ZM in the created doped region 13 is selected by choosing its size and position, solving the wave equation, which determines the value

, as well as by choosing the concentration and type of dopant.

The inventive injection laser operates as follows. An electrical current is passed through a strip ohmic contact 7 of the inventive injection laser (see FIG. 2) in a direction perpendicular to the layers of the heterostructure, and the operation mode of the injection laser (laser diode) corresponds to the forward bias of the p-n junction. When the current passed through the injection laser is exceeded by a threshold value through a naturally chipped face — mirror 5 with an antireflection coating — the Fabry-Perot mode laser radiation comes out. The output radiation power, in addition to the structure parameters, depends on the magnitude of the current transmitted through the laser heterostructure. Spontaneous emission on the generation line of the closed mode is absorbed in the doped region 13 (see figure 2). This suppresses closed loop feedback. As a result, only the Fabry-Perot resonator modes are retained, which preserves the linearity of the dependence of the output power on the pump current and an increase in the output optical power.

Example. Comparative tests have been conducted of the known injection laser and the inventive injection laser. Injection was made known laser based heterostructure waveguide layer consisting of GaAs 0,6 um thick enclosed between the emitter of wide-Al _0.3 Ga _0.7 As p-type conductivity and a thickness of 1.5 microns wide-emitter Al _0.3 Ga _0.7 As n-type conductivity in thickness 1.5 μm, the active region consisting of one In _0.26 Ga _0.74 Аs quantum-well active layer with a thickness of 8.5 nm, a Fabry-Perot optical resonator 1.5 mm long, formed naturally by a cleaved face with an antireflection coating having a reflection coefficient 5%, and the edge with a reflective coating having a reflectivity of 95%, a strip ohmic contact 100 μm wide, located in the center between laterally naturally chipped faces, the distance between which is 500 μm, an n-type GaAs substrate. For a well-known injection laser, the values of internal optical losses and losses at the output of radiation for the Fabry-Perot resonator modes were 2 cm ^-1 and 10.15 cm ^-1 , respectively. An electric current was passed through a strip contact of a known injection laser (see FIG. 1) in a direction perpendicular to the layers of the heterostructure, and the injection laser operating mode corresponds to a forward bias of the pn junction. In the first version of the pump, a continuous current was passed; in the second version of the pump, a pulse current was passed with a current pulse duration of 100 ns and a frequency of 10 kHz. For a known injection laser, the dependence of the optical power exiting through the face coated with an antireflection coating on the continuous pump current is shown in Fig. 5 (curve 3), for a pulsed pump current it is shown in Fig. 5 (curve 4). The output optical power reached its maximum value with a continuous pump current of 5.4 W, and with a pulsed pump current of 34.5 W.

=0.2, значение составляющей фактора оптического ограничения Г_Y в области усиления для ЗМ

=0.2. При выбранных параметрах области легирования неравенствоThe inventive injection laser was different from the known injection laser in that a doped region was formed in the waveguide layer. Doping was carried out with zinc, an admixture of p-type electrical conductivity, to a concentration of p = 10 ¹⁸ cm ^-3 with an absorption cross section on free holes in the doped region σ _p = 7 * 10 ^-18 cm ² . The boundary of the doped region closest to the injection region was located at a distance of 100 μm. The width of the doping region was 100 μm; the optical restriction factor of ZM in the doped region

= 0.2, the value of the component of the optical limiting factor Г _Y in the amplification region for ZM

= 0.2. With the chosen parameters of the doping region, the inequality

performed. An electric current was passed through the strip ohmic contact of the proposed injection laser (see Fig. 2) in the direction perpendicular to the layers of the heterostructure, and the injection laser operation mode corresponded to the forward bias of the pn junction. In the first version of the pump, a continuous current was passed; in the second version of the pump, a pulse current was passed with a current pulse duration of 100 ns and a frequency of 10 kHz. For the inventive injection laser, the dependence of the optical power exiting through the face with the antireflection coating on the continuous pump current is shown in Fig. 5 (curve 5), for a pulsed pump current it is shown in Fig. 5 (curve 6). The output optical power reached its maximum value with a continuous pump current of 8.8 W, with a pulsed pump current of 54.5 W. The output optical power values obtained for the injection laser turned out to be higher than that of the known injection laser. Measurements of the output optical power over time showed that the temporal stability of the signal of the inventive injection laser is higher than that of the known injection laser. Thus, the inventive injection laser has an increased output optical power in continuous and pulsed mode, and also has increased temporal stability of the output optical power.

Claims (13)

1. Injection laser based on a heterostructure, comprising a first waveguide layer, enclosed between wide-gap p- and n-type emitters, which are simultaneously boundary layers, an active region consisting of at least one quantum-dimensional active layer, an optical Fabry A pen resonator and a strip ohmic contact, under which an injection region is located, characterized in that at least one doped region is made in at least one doped region at least in the first waveguide layer outside the injection region, When this optical confinement factor closed fashion (ZM) in the doped region and the free charge carrier concentration in the doped region satisfy the relation

Where

- the value of the constituent factor of the optical limitation G _Y in the amplification region for ZM, rel. units;

- losses at the exit of the Fabry-Perot fashion, cm ^-1 ;
α _i - internal optical absorption loss on free charge carriers in the amplification region, cm ^-1 ;
Δα is the optical loss associated with the scattering of ZM radiation by inhomogeneities (α _SC ), interband absorption (α _BGL ) and absorption on free charge carriers in the sides of the injection laser relative to the strip ohmic contact, cm ^-1 ;

- factor of optical limitation of ZM in the doped region, rel. units;
σ _n is the absorption cross section for free electrons in the doped region, cm ² ;
n is the concentration of free electrons in the doped region, cm ^-3 ;
σ _p is the absorption cross section for free holes in the doped region, cm ² ;
p is the concentration of free holes in the doped region, cm ^-3 . 2. The injection laser according to claim 1, characterized in that the distance between the nearest boundaries of the doped region and the injection region is not less than 10 μm. 3. The injection laser according to claim 1, characterized in that the width of the doped region is not less than 10 microns. 4. The injection laser according to claim 1, characterized in that the doped region contains, as a dopant of n-type conductivity, an element selected from the group: Si, Te, Ge, Sn, or a combination thereof. 5. The injection laser according to claim 4, characterized in that the concentration of the dopant of the n-type conductivity is not less than 10 ¹⁸ cm ^-3 . 6. The injection laser according to claim 1, characterized in that the doped region contains as an alloying impurity of p-type conductivity an element selected from the group: C, S, Mg, Be, Zn, or a combination thereof. 7. The injection laser according to claim 6, characterized in that the concentration of the dopant of the p-type conductivity is not less than 10 ¹⁷ cm ^-3 . 8. The injection laser according to claim 1, characterized in that the doped region is formed by ion bombardment. 9. The injection laser according to claim 1, characterized in that the doped region is formed by diffusion of the impurity from the surface layers into the waveguide layer. 10. The injection laser according to claim 1, characterized in that at least in the first waveguide layer outside the injection region there are two doped regions located in the lateral parts of the injection laser. 11. The injection laser according to claim 1, characterized in that it contains a second waveguide layer with a band gap less than the band gap of the first waveguide layer, and the active region is located in the second waveguide layer. 12. The injection laser according to claim 1, characterized in that the longitudinal size of the doped region is less than the length of the optical Fabry-Perot resonator. 13. The injection laser according to claim 1, characterized in that the heterostructure is made in a system of solid solutions A ³ B ⁵ .

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