RU2549553C2 - Injection laser - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: injection laser includes semiconductor heterostructure containing waveguide layer between top and bottom wide-band emitters of p- and n-type conductivity respectively, serving as limiting layers as well, with active zone consisting of at least one quantum-confined active layer, optical Fabry-Perot resonator and ohmic contact strip under which injection zone is positioned, so that top p-type emitter features mesa cavities in ohmic contact area with length equal to or less than ohmic contact width and positioned at equal distances with pitch defined by a given ratio. Cross-section of mesa cavities has wedge shape with one side perpendicular to optical Fabry-Perot resonator axis and the other side tilted outwards at 25-60 degrees angle to plane of the first side of mesa cavity.

EFFECT: possible generation of narrow emission band by injection laser.

3 dwg

Description

The present invention relates to quantum electronics and quantum amplifiers, namely to high-power semiconductor lasers with distributed feedback.

Powerful semiconductor lasers are widely used in many fields of scientific activity and industry, for example, as sources of optical radiation for pumping solid-state and fiber lasers and amplifiers. Semiconductor lasers are widely used due to the achievement of a high value of efficiency and output optical power. The development of modern approaches to the design of high-power semiconductor lasers has made it possible to significantly reduce the value of internal optical loss (less than 1 cm ^-1 ) and to reach the limit value of the internal quantum yield (more than 99%). Improvements in these parameters of the semiconductor laser made it possible to obtain record values of the output optical power, both in continuous and in pulsed operation. But at the same time, an increase in power is accompanied by a significant increase in the width of the laser generation spectrum, which leads to a decrease in the spectral density of radiation power. This increase in the width of the laser generation spectrum is due to the heating of the laser heterostructure due to the flow of electric current through it. An increase in the width of the generation spectrum of a high-power semiconductor laser significantly reduces the optical pumping efficiency of solid-state and fiber lasers because they have a spectrally narrow absorption line. To narrow the generation spectrum of a high-power semiconductor laser, various design solutions are used. They can be divided into two groups: solutions presented in an integrated version, and in the form of external elements.

In the case of external elements (see - George B. Venus, Armen Sevian, Vadim I. Smirnov, Leonid B. Glebov - "High-brightness narrow-line laser diode source with volume Bragg-grating feedback". - Proc. SPIE 5711, High-Power Diode Laser Technology and Applications III, 166, March 17, 2005) use an external selective resonator having an increased Q factor in a narrow spectral range, which overlaps with the material gain of the active region of the laser heterostructure. The disadvantage of this solution is the high sensitivity to mechanical stress on the device and the need for ultra-precise alignment of the external resonator. Another negative aspect of this solution is the high cost of the external cavity, which often exceeds the cost of the semiconductor laser itself.

In view of the above reasons, it is more efficient to use semiconductor lasers, the selective feedback of which is carried out in the integral representation.

A known injection laser (see US 6107112, IPC H01L 21/00 H01S 5/00, published 08/22/2000) containing a laser heterostructure with waveguide layers, an active, Fabry-Perot optical resonator. In one of the layers of the laser heterostructure, a lattice is made of periodically arranged mesoscopic grooves having a triangular cross-sectional shape and perpendicular to the Fabry-Perot optical resonator. The mesoscopic grooves are overgrown with the following heterostructure layers.

The radiation spectrum of the known injection laser consists of two longitudinal modes, which negatively affects the width of the spectral line of radiation. Also, the formation of a lattice of mesoscopic grooves inside the heterostructure significantly complicates the process of manufacturing an injection laser.

Known injection laser (see patent US 6477194, IPC H01S 3/08, published 05.11.2002), including a laser heterostructure with waveguide layers and an active region containing quantum wells, and an optical Fabry-Perot resonator. In one of the layers of the heterostructure, a lattice is made of periodically arranged triangular-shaped mesoscans located perpendicular to the Fabry-Perot optical resonator and overgrown with the following layers of the heterostructure.

The well-known injection laser with distributed feedback has a narrow generation spectrum. Owing to the presence of additional optical losses in the grating region, the laser mode located at the short-wavelength edge of the band gap has lower threshold values than other resonator modes. The disadvantages of the known injection laser include the need for its operation at low temperatures, which significantly limits the use of the laser.

An injection laser is known (see J. Fricke, N. Wenzel, F. Bugge, O.P. Brox, A. Ginolas, W. John, P. Ressel, L. Weixelbaum, G. Erbert. - "High-Power Distributed Feedback Lasers With Surface Gratings ". - IEEE Photonics Tech. Lett., Vol. 24, No. 16, 2012), coinciding with this solution for the largest number of essential features and selected as a prototype. The injection laser prototype includes a semiconductor heterostructure consisting of a waveguide layer enclosed between the confining layers of n- and p-types of conductivity, containing at least one quantum-dimensional active region. In the p-type conduction boundary layer, meshes are formed perpendicular to the axis of the Fabry-Perot optical resonator, which ensure the presence of distributed feedback. The depth of the grooves is equal to the thickness of the p-type confining layer and is 1.35 μm. The width of the mezzanine is 0.5 μm. The length of the mesa groove is equal to the width of the ohmic contact and is 90 μm. The cross-sectional grooves have a symmetrical V-shape (the shape of an isosceles triangle). The meshes are located equidistantly along the entire length L of the Fabry-Perot optical resonator with a period determined from the relation:

; $$\Lambda =\frac{m\lambda }{2n},\text{μm}$$

;

; $$\frac{\lambda }{2n}\le \Lambda \le 0.8\cdot {10}^{-2}\cdot L$$

;

where Λ is the period of the location of the mesanas, microns;

m is a positive integer;

λ is the wavelength of the laser radiation, microns;

n is the effective refractive index of the waveguide layer;

L is the length of the Fabry-Perot optical resonator, microns.

определяет минимально значение количества мезаканавок для обеспечения эффективной распределенной обратной связи в инжекционном лазере.Condition $$\frac{\lambda }{2n}\le \Lambda \le 0.8\cdot {10}^{-2}\cdot L$$

determines the minimum value of the number of grooves to ensure effective distributed feedback in the injection laser.

A disadvantage of the known injection laser prototype is the presence of two eigenmodes of the resonator with distributed feedback with the same threshold gain. As a result, the spectrum of a semiconductor laser has a multimode composition and expands significantly with increasing current injection level.

The objective of this technical solution is to develop such an injection laser, which would have a narrowed spectrum of radiation.

The problem is solved in that the injection laser includes a semiconductor heterostructure containing a waveguide layer enclosed between the upper and lower wide-band emitters of p- and n-type conductivity, respectively, which are simultaneously boundary layers, with an active region consisting of at least one quantum-dimensional active layer, a Fabry-Perot optical resonator, and a strip ohmic contact, under which the injection region is located. In the upper p-type emitter in the ohmic contact region, meshes are made with a length equal to or less than the ohmic contact width, with a depth of at least equal to the thickness of the upper p-type emitter and equidistantly located with a period determined from the relations:

; $$\Lambda =\frac{m\lambda }{2n},\text{μm}$$

;

; $$\frac{\lambda }{2n}\le \Lambda \le 0.8\cdot {10}^{-2}\cdot L\text{μm}$$

;

where Λ is the period of the location of the mesanas, microns;

m is a positive integer;

λ is the wavelength of the laser radiation, microns;

n is the effective refractive index of the waveguide layer;

L is the length of the Fabry-Perot optical resonator, microns.

New in this injection laser is the implementation of wedge shaped grooves in the cross section in the form of a wedge, one of the faces of which is perpendicular to the axis of the Fabry-Perot optical resonator, and the second face is tilted outward at an angle of 25-60 degrees to the plane of the first face of the mesa groove.

The choice of the interval of tilt angles of 25-60 degrees of one of the faces of the mezzanines is due to the following. Theory of coupled modes (see A. Yariv - Introduction to Optical Electronics. - Moscow, Higher School, 1983; N. Ghafouri-Shiraz, BSK Lo - Distributed Feedback Laser Diodes: Principles and Physical Modeling. - NY, John Wiley & Sons, 1996) describes the behavior of the propagation of electromagnetic radiation in a waveguide medium with periodic modulation of the dielectric constant. In this theory, the stationary wave equation is solved:

; $$\Delta E\left(x,y,z\right)+\epsilon \left(x,y,z\right)\cdot k_0^2\cdot E\left(x,y,z\right)=0$$

;

where E (x, y, z) is the distribution of the electromagnetic field, V / m;

Δ is the Laplace operator;

k ₀ - wave vector of the electromagnetic field in vacuum, cm ^-1 ;

ε (x, y, z) is the dielectric constant of the waveguide layer.

The dielectric constant of the waveguide layer has a periodicity along the axis of the Fabry-Perot optical resonator in accordance with the frequency of arrangement of the meshes:

ε (x, y, z) = ε ₀ (x, y) + Δε (x, y, z);

Δε (x, y, z) = Δε (x, y, z + Λ):

where ε ₀ is the background dielectric constant of the waveguide layer;

Δε is the amplitude of the modulation of the dielectric constant of the waveguide layer caused by the presence of a diffraction grating;

Λ is the period of the location of the mesanas, microns.

The solution of this wave equation leads to the fact that the distribution of the electromagnetic field along the axis of the Fabry-Perot optical resonator is two waves, one - running in the direction of plus infinity, the second - in the direction of minus infinity:

E (z) = E _f (z) · e ^iβz + E _b (z) · e ^-iβz ;

where E (z) is the distribution of the electromagnetic field along the axis of the Fabry-Perot optical resonator, V / m;

β is the wave vector of the electromagnetic field in the medium, cm ^-1 ;

E _f (z) - the amplitude of the wave traveling to the side plus infinity, V / m;

E _b (z) is the amplitude of the wave traveling to the side minus infinity, V / m.

In this case, the amplitudes of the traveling waves E _f (z), E _b (z) are functions of the coordinate and depend on each other, which indicates that the waves exchange energy. The amplitudes of the traveling waves satisfy the system of differential equations:

, $$\frac{d{E}_f\left(z\right)}{dz}=i{\kappa }_f{E}_b\left(z\right)e^{-2i\left(\beta -\beta o\right)z}$$

,

, $$\frac{d{F}_b\left(z\right)}{dz}=-i{\kappa }_b{E}_f\left(z\right)e^{2i\left(\beta -\beta o\right)z}$$

,

, $$\beta 0=\frac{m\pi }{\Lambda }$$

,

Where

β0 is the Bragg wave vector, cm ^-1 ;

i is the imaginary unit;

m is a positive integer;

κ _f is the coupling coefficient of the wave traveling in the direction of plus infinity, with the wave running in the direction of minus infinity, cm ^-1 ;

κ _b is the coupling coefficient of the wave traveling in the direction of minus infinity, with the wave running in the direction of plus infinity, cm ^-1 .

They are determined by the relations:

$${\kappa }_f=\frac{k_0^2}{2\beta }\frac{{\displaystyle \underset{Vg}{\int }{\Delta }^m{\epsilon }_f{U}^2\left(x,y\right)dxdy}}{{\displaystyle \underset{-\infty }{\overset{+\infty }{\int }}{U}^2\left(x,y\right)dxdy}}$$

$${\kappa }_b=\frac{k_0^2}{2\beta }\frac{{\displaystyle \underset{Vg}{\int }{\Delta }^m{\epsilon }_b{U}^2\left(x,y\right)dxdy}}{{\displaystyle \underset{-\infty }{\overset{+\infty }{\int }}{U}^2\left(x,y\right)dxdy}}$$

where k ₀ is the wave vector of the electromagnetic field in vacuum, cm ^-1 ;

β is the wave vector of the electromagnetic field in the medium, cm ^-1 ;

U (x, y) is the distribution of the electromagnetic field in a plane perpendicular to the axis of the Fabry-Perot optical resonator;

Δ ^m ε _f - m-Fourier component of the modulation of the dielectric constant Δε for a wave traveling in the direction of plus infinity;

Δ ^m ε _b - m-Fourier component of the modulation of the dielectric constant Δε for a wave traveling in the direction of minus infinity;

Vg - region of the lattice in a plane perpendicular to the axis of the Fabry-Perot optical resonator, cm ² .

The ratio of the amplitudes E _f (z), E _b (z) will give the reflection coefficient of the diffraction grating formed by the meshes. To achieve a high value of the reflection coefficient of the diffraction grating, the number of mesoscopic deposits must be large, which imposes a condition on the value of the period for a given length of the laser cavity. Calculations show that the condition must be met:

L / Λ≥1.25 · 10 ² ,

where L is the length of the optical Fabry-Perot resonator, microns;

Λ is the period of the location of the mesanas, microns.

The reflection coefficient of the diffraction grating is a continuous function of the wavelength. In the case of a real injection laser with a finite length of the Fabry-Perot optical resonator and reflecting faces at its ends, the boundary conditions are imposed on the system of differential equations:

E _f (z = a) = r ₁ · E _b (z = a);

r ₂ · E _f (z = b) = E _b (z = b);

where a is the coordinate of the beginning of the Fabry-Perot optical resonator, microns;

b - coordinate of the end of the Fabry-Perot optical resonator, microns;

r ₁ - reflection coefficient of the end face of the Fabry-Perot resonator located in the plane z = a (face 5 in figure 1);

r ₂ is the reflection coefficient of the end face of the Fabry-Perot resonator located in the plane z = b (face 6 in figure 1).

When these boundary conditions of the Fabry-Perot optical resonator are superimposed on the system of differential equations, we obtain a set of discrete values of the threshold conditions for the generation of laser radiation. Each discrete value is characterized by two parameters (a, δ),

where a is the threshold modal gain, cm ^-1 ;

δ is the shift of the radiation generation wavelength, relative to the central radiation wavelength, defined by the relation λ = 2 · n · Λ / m, μm.

From this analysis it follows that there are two resonator modes with distributed feedback, which are located at wavelengths Δ = 2 · n · Λ / m ± δ with threshold modal gain a ₁ and a ₂ . In the injection laser prototype k _f = k _b , that is, there is an equal energy exchange between the waves, a ₁ = a ₂ , as a result, two equivalent peaks of laser radiation are generated in the injection laser prototype.

In the present injection laser, which has an asymmetric cross-sectional shape of the mesoscopic grooves (one of the faces of the mesoscopic groove is perpendicular to the axis of the Fabry-Perot optical resonator, and the second face is tilted outward at an angle of 25-60 degrees to the plane of the first face of the mesoscopic groove), the condition κ _f ≠ κ _{b is} achieved. When this condition is met, the solution of the system is also two discrete values, but the threshold amplification values of the two modes will differ, that is, a ₁ ≠ a ₂ . With this geometry, the magnitude of the reflection of the traveling wave in the waveguide from each mesoscopic groove depends on the direction of radiation propagation. In this case, the energy exchange between the traveling waves is different, which explains the priority operation of the injection laser on one of the modes, since the radiation will be amplified only on the mode with a lower threshold gain. To achieve single-mode laser generation at high levels of current injection, it is necessary to achieve a significant difference for the threshold amplification of different modes (a ₁ << a ₂ ). At high values of the pump current density, the injected carriers can begin to emit through the laser recombination channels, which have significantly higher threshold conditions compared to the main laser mode. This effect will be manifested the later (at a higher pump current), the greater the difference in threshold modal gain. To determine the optimal ratio between the threshold conditions of the fundamental mode of the laser and the first non-fundamental mode, experiments were performed. During the experiment, samples of semiconductor lasers with distributed feedback with asymmetric meshes were made. The samples differed in different angles of inclination of the oblique face of the mesotrope to the face plane located perpendicular to the axis of the Fabry-Perot optical resonator. The experiment showed that the single-mode laser operation at a pump current density of 6 kA / cm ^{2 is} maintained at an angle of inclination of 25-60 degrees, which corresponds to the ratio a2 / a1≥1.5 according to calculations. At tilt angles of less than 25 degrees and more than 60 degrees, multimode laser generation is observed at a pump current density of less than 6 kA / cm ² .

The depth of the meso-groove may differ from the thickness of the bounding layer of the p-type conductivity. At the same time, the depth of the mesoscopic groove cannot exceed the distance from the upper boundary of the p-type confining layer to the active region; penetration of the mesoscopic grooves into the active region catastrophically degrades the radiating properties of the semiconductor heterostructure. The minimum depth of the mesoscopic groove (less than the thickness of the upper bounding layer of the p-type conductivity) is limited by the interaction of laser radiation with the region of the mesoscopic grooves, which is determined by the ratio:

, $$G=\frac{{\displaystyle \underset{Vg}{\int }{U}^2\left(x,y\right)dxdy}}{{\displaystyle \underset{-\infty }{\overset{+\infty }{\int }}{U}^2\left(x,y\right)dxdy}}$$

,

where G is the gamma factor of the optical limitation of the electromagnetic field in the region of the mezzanines;

U (x, y) is the distribution of the electromagnetic field in the plane perpendicular to the axis of the Fabry-Perot optical resonator;

Vg is the region of the lattice in a plane perpendicular to the axis of the Fabry-Perot optical resonator, cm ² .

To achieve the effective operation of the injection laser with distributed feedback, the condition must be satisfied that Г≥0.015.

Mesh grooves can be performed using reactive ion etching or chemical etching.

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

The inventive injection laser is illustrated by drawings, where

figure 1 is a schematic perspective view of a true injection laser;

figure 2 shows the present injection laser in the context, in the upper bounding layer of which made mesanine grooves in accordance with the invention;

figure 3 presents the emission spectra of various semiconductor lasers with a continuous pump current significantly exceeding the generation threshold (curve 1 is the real injection laser, curve 2 is the injection laser prototype, curve 3 is the injection laser without distributed feedback).

The present injection laser (see Fig. 1) contains a waveguide layer 1, sandwiched between the upper wide-band p-type emitter 2 and the lower wide-band n-type emitter 3, which are both boundary layers, the active region 4 in the waveguide layer 1, consisting of at least one quantum-well active layer, a Fabry-Perot optical resonator, formed naturally by a cleaved face 5 with an antireflection coating and a face 6 with a reflective coating, a strip ohmic ntakt 7, which is located under the injection region 8, 9 comprising a gain region, the lateral naturally cleaved facets forming the lateral limiting surface 10, substrate 11, the side portion 12 of the injection laser mezakanavki 13 disposed in ohmic contact 7 and perpendicular to it. The waveguide layer 1, the upper wide-gap emitter 2 of p-type conductivity and the lower wide-gap emitter 3 of n-type conductivity, which are both boundary layers, the active region 4 in the waveguide layer 1, consisting of at least one quantum-dimensional active layer, constitute a semiconductor heterostructure 14. The mesanal grooves 13 in cross section (see figure 2) are made in the form of a wedge. One of the faces, for example, face 15, is perpendicular to the axis of the Fabry-Perot optical resonator, and the second face 16 is tilted outward at an angle of 25-60 degrees to the plane of the first face 15 of the mezzanine 13. The mesanine 13 can have a length equal to or less than the width of the ohmic contact 7, and a depth at least equal to the thickness of the upper wide-gap p-type conductivity emitter 2. Mesa grooves 13 are equidistantly located with a period Λ, determined from the relations:

; $$\Lambda =\frac{m\lambda }{2n},\text{μm}$$

;

$$\frac{\lambda }{2n}\le \Lambda \le 0.8\cdot {10}^{-2}\cdot L\text{μm}$$

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

The present injection laser operates as follows. An electric current is passed through a strip ohmic contact 7 of the injection laser (see FIG. 1) in a direction perpendicular to the layers of the heterostructure 14, and the operation mode of the injection laser (laser diode) corresponds to the forward bias of the pn junction. When the current passed through the injection laser is exceeded, the threshold value is transmitted through a naturally cleaved face 5 (mirror) with an antireflection coating and the laser radiation of the Fabry-Perot optical resonator mode with distributed feedback comes out. The power of the output radiation depends on the magnitude of the current transmitted through the laser heterostructure 14.

The radiation propagating in the waveguide layer 1 is reflected from the meshes 13, while the interference gain is experienced only by radiation with a long wave satisfying the condition λ = 2 · n · Λ / m + δ or λ = 2 · n · Λ / m-δ ( depending on the relative location of the oblique face 16 of the meshes 13 and face 15, perpendicular to the axis of the Fabry-Perot optical resonator and parallel to the end face 5 with the antireflection coating of the Fabry-Perot resonator (see Fig. 2). Emissions at other wavelengths are not amplified in the semiconductor heterostructure that leads to the operation of a real injection laser in a narrow stable spectrum.

Example 1. Comparative tests were carried out of an injection laser without distributed feedback, a known injection laser with distributed feedback, which had mesoscopic grooves with a symmetrical cross-section, and a real injection laser with distributed feedback, which had mesan grooves with a asymmetric cross-section. For this purpose was made known injection laser comprising a semiconductor heterostructure comprising a waveguide layer of GaAs 0,8 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 - conductivity type with a thickness of 1.5 μm, the active region consisting of one quantum-well active layer In _0.28 Ga _0.72 As 8.3 nm thick; 3 mm long Fabry-Perot optical resonator, formed naturally by a cleaved face with an antireflection coating having a reflectance of 5% and a face with a reflective coating having a reflectivity of 95%, a strip ohmic contact 100 μm wide, located in the center between the side chipped faces, the distance between which is 400 microns, an n-type GaAs substrate. A continuous electric current was passed through the strip contact of the injection laser in the direction perpendicular to the layers of the semiconductor heterostructure, and the injection laser operating mode corresponded to the forward bias of the pn junction. For an injection laser without distributed feedback, the generation spectrum at a pump current ten times the threshold value is shown in Fig. 3 (curve 3). The well-known injection laser prototype with distributed feedback differed from the injection laser without distributed feedback in that mesonic grooves of a symmetrical wedge-shaped shape, perpendicular to the axis of the Fabry-Perot optical resonator, were formed in the p-type Al _0.3 Ga _0.7 As wide-gap emitter layer. The faces of the mezzanine were tilted at an angle of 21 degrees to the plane perpendicular to the axis of the Fabry-Perot optical resonator. The length of the mesoscopic groove coincided with the width of the ohmic contact and was 100 μm, the width of the mesoscopic groove on the surface of the heterostructure was 1.2 μm, the width of the mesoscopic groove near the boundary of the waveguide and the upper emitter layer was 0.1 μm, and the depth of the meshed groove was 1.4 μm. The distance between the mezzanines was 20 μm. The geometric shape of the meshes was symmetrical, which ensured the same exchange between the waves propagating in waveguide layer 1. For the known injection laser prototype, the generation spectrum at a pump current ten times the threshold value is shown in Fig. 3 (curve 2). The present injection laser differed from the known injection laser of the prototype in that mesicular grooves having an asymmetrical wedge-shaped cross section were formed in the p-type Al _0.3 Ga _0.7 As wide-gap emitter layer. One face of the mezzanine was formed perpendicular to the axis of the Fabry-Perot optical resonator, the other face was inclined at an angle of 38 ° to the plane perpendicular to the axis of the Fabry-Perot optical resonator. The length of the mesoscopic groove coincided with the width of the ohmic contact and was 100 μm, the width of the mesoscopic groove on the surface of the heterostructure was 1.2 μm, the width of the mesoscopic groove near the boundary of the waveguide and the upper emitter layer was 0.1 μm, and the depth of the meshed groove was 1.4 μm. The distance between the mezzanines was 20 μm. For a real injection laser, the generation spectrum at a pump current ten times the threshold value is shown in FIG. 3 (curve 1). The spectrum width of the injection laser without distributed feedback at half maximum intensity was 5 nm. The spectrum of the injection laser prototype with distributed feedback formed by symmetrical-shaped meshes was characterized by two generation peaks. The width of each peak at half maximum intensity was 0.5 nm, the distance between the peak is about 1 nm. The spectrum of a real laser with distributed feedback formed by asymmetric mesoscalls has one lasing peak. The peak width at half maximum intensity was 0.5 nm. Thus, a true injection laser has a narrow, stable emission spectrum with a single lasing peak.

Example 2. A real injection laser was made, which differs from the injection laser described in Example 1 in that the conductivity was formed by meshes, in which one face was perpendicular to the axis of the Fabry-Perot optical resonator, and the other face was tilted at an angle of 25 ° to a plane perpendicular to the axis of the Fabry-Perot optical resonator. The laser spectrum shown in Example 2 contained 1 lasing peak at a pump current ten times the threshold value. The width of the lasing peak at half maximum intensity was 0.5 nm.

Example 3. A real injection laser was made, which differs from the injection laser described in Example 1 in that mesoscanules were formed in which one face was perpendicular to the axis of the Fabry-Perot optical resonator and the other face was tilted at an angle of 60 ° to a plane perpendicular to the axis of the Fabry-Perot optical resonator. The laser spectrum shown in Example 3 contained 1 lasing peak at a pump current ten times the threshold value. The width of the lasing peak at half maximum intensity was 0.5 nm.

Claims (4)

1. An injection laser comprising a semiconductor heterostructure containing a waveguide layer enclosed between the upper and lower wide-band emitters, respectively, of p- and n-type conductivity, which are simultaneously boundary layers, with an active region consisting of at least one quantum-dimensional active layer, an optical Fabry-Perot resonator and a strip ohmic contact, under which the injection region is located, and in the upper p-type emitter in the ohmic contact region, mesak Navki length equal to or less than the width of the ohmic contact, and equidistantly arranged with the period determined from the relations:
$$\Lambda =\frac{m\lambda }{2n},\text{microns;}$$

$$\frac{\lambda }{2n}\le \Lambda \le 0.8\cdot {10}^{-2}\cdot L\text{μm};$$

where Λ is the period of the location of the mesanas, microns;
m is a positive integer;
λ is the wavelength of the laser radiation, microns;
n is the effective refractive index of the waveguide layer;
L is the length of the Fabry-Perot optical resonator, microns;
in this case, the meso-grooves in the cross section are made in the form of a wedge, one of the faces of which is perpendicular to the axis of the Fabry-Perot optical resonator, and the second face is tilted outward at an angle of 25-60 degrees to the plane of the first face of the meso-groove. 2. The laser according to claim 1, characterized in that the mezzanines are made of chemical etching. 3. The laser according to claim 1, characterized in that the mezzanines are made by reactive ion etching. 4. The laser according to claim 1, characterized in that the semiconductor heterostructure is made in the system of solid solutions A ³ B ⁵ .

Images