FR3076404A1 - MONOLITHIC INFRARED SOURCE - Google Patents

Abstract

The invention relates to a device (10) for generating a signal beam (Bs) having a signal wavelength (λs) of between 2 and 15 μm, the device comprising: a multilayer laser source (LS), a quasi-phase-locked multilayer optical waveguide (QAPG), called a guide, the laser source (LS) and the guide (QAPG) being coupled so that the pump beam (Bp) issuing from the active layer (AL) ) of the laser source (LS) is injected into the core (GL) of the guide (QAPG), the layers of the guide being produced by epitaxy on a substrate (Sub) and comprising, along the Z axis, an alternation of first zones (Z1) having a first crystallographic orientation and second zones (Z-1) having an inverted crystallographic orientation with respect to the first crystallographic orientation, so as to effect energy transfer from the pump beam (Bp) to the signal beam (Bs) and a complementary beam by quasi acco rd phase, -the layers of the laser source is also produced by epitaxy, thus forming with the layers of the guide and the substrate (Sub) a monolithic crystalline block.

Description

FIELD OF THE INVENTION

The invention relates to the production of coherent sources of medium-infrared photons, that is to say of wavelength between 2 and 15 μm from a so-called pumping laser diode and a converter of the wavelength of this diode operating in a guided configuration and on the principle of quasi-phase agreement (QAP) in a semiconductor material with high non-linear coefficient of order two.

STATE OF THE ART

The production of components capable of emitting in the IR medium, both compact, presenting a reduced cost, a wide range of accessible wavelengths and a high energy efficiency is an important stake for a wide range of applications, in in particular those which exploit the spectroscopic properties of the region known as infrared fingerprints, ranging from the analysis of pollutants to ophthalmic surgery through the structuring of organic photovoltaic cells.

Despite significant scientific advances that have revitalized the field of infrared sources with wavelengths greater than two microns in recent years, these sources have not yet reached the necessary maturity. Lighting on the locks to be lifted is provided by the user's point of view on the characteristics of these sources, which can be separated into two groups:

- The first includes gas, semiconductor and rare earth or transition metal doped lasers, in solid or fiber form, which directly generate infrared photons from an optical or electric pumping device. Spectral ranges above two microns are generally more difficult to obtain and the tunability of these sources is often limited.

In the case of semiconductors, however, their cost can potentially benefit from significant economies of scale.

- The second regroups the sources based on the frequency conversion of pumping lasers emitting between 1 and 2.5 microns towards the longest wavelengths, by parametric effect in non-linear optical materials of order two or by generation of supercontinuum from short pulses. It is often possible to have them emitted over a greater wavelength range than the sources of the first group, but at a higher cost often linked to the pump / converter coupling.

It is known that second order non-linear materials allow parametric conversion of the wavelength of a pumping beam, denoted λ _Ρι into two longer wavelengths, denoted λ _δ (signal beam) and λ ₀ (complementary beam or "idler"), which respect the law of conservation of energy:

1 / λρ = 1 / λ _δ + 1 / λ ₀

The parameter which decides the values of λ _δ and λ ₀ among the different possible couples is deduced from the condition of phase agreement between these three waves. The dispersion of the optical indices makes it possible in practice to satisfy this condition for a limited number of birefringent materials. Unfortunately, these materials do not necessarily have the best non-linear coefficients, large operating wavelength ranges, sufficient operating temperature and beam focusing ranges.

The use of optical networks composed of structures based on non-linear optical crystals makes it possible, under certain conditions, to overcome some of these limitations. For this we use the technique of phase quasi-agreement, or QAP (Quasi Phase Matching or QPM in English) which consists in making local modifications of the non-linear coefficient of order 2 or χ ⁽²⁾ so that the disagreement of phase between waves accumulated during propagation is periodically compensated. An artificial nonlinear network of period A is thus created as illustrated in FIG. 1, with Fp pump beam, Fs signal beam and Fc complementary beam.

In ferroelectric materials such as lithium niobate, it is known to reverse the sign of the dielectric polarization of domains a few micrometers wide, throughout the depth, by application of an electric field along the crystallographic axis of this material. The propagating beam sees a modulation of the susceptibility favorable to QAP.

Certain semiconductors, such as gallium arsenide, denoted GaAs, exhibit both high non-linear coefficients and wide ranges of transparency. However, these crystals belong to the crystallographic class of cubic symmetry, which makes them isotropic, and therefore unsuitable for the traditional birefringent phase agreement. On the other hand, they do not have the ferroelectric properties of lithium niobate. It is however possible to use GaAs using the QAP technique by manufacturing structures with periodically inverted crystal orientation, noted OP from the English “Orientation-Patterned”. We thus also obtain a χ ⁽²⁾ whose sign reverses periodically.

Unlike non-linear crystals designed for a birefringent phase agreement, QAP materials allow effective interactions over their entire range of transparency and are therefore components of choice for the production of coherent sources that are largely tunable. Depending on the need, their emission wavelengths can be tuned by changing the temperature T of the crystals, the period A of the QAP or the pumping wavelength. For a QAP at order 1, these quantities are conventionally linked by the following equation, where the symbols n, (T) represent the refractive indices at temperature T at the different wavelengths λρ, As, Ac:

η _ρ (Τ) / λ _ρ - n _s (T) / A _s - n _c (T) / A _c = 1 / Λ

FIG. 2 gives an example of doublets of accessible wavelengths (As, Ac) as a function of Ap for the gallium arsenide with periodic orientation (ΟΡ-GaAs in English). FIG. 3 gives an example of doublets of accessible wavelengths (As, Ac) as a function of Ap for ΙΌΡ-GaAs (zoom in wavelength) and for lithium niobate with periodic polarization (PPLN in English), at room temperature and for massive crystals. We find that QAP semiconductor materials like comme’ΟΡ-GaAs offer a much wider choice of converted wavelengths in the mid-infrared than oxides like PPLN.

We also know that pumping at a longer wavelength is favorable to greater tunability and is also useful for limiting parasitic effects such as two-photon absorption. To generate long wavelengths, we also show that it is more interesting in terms of conversion efficiency to use pumping which is also as high as possible in wavelength, in order to minimize the quantum defect.

Many architectures of infrared sources take advantage of these massive materials. For devices that consume less pumping power, guided configurations have been proposed. Subject to designing waveguides offering sufficient overlap between the modes propagated at the three wavelengths of interest, the high power densities linked to confinement allow very effective non-linear interactions. The preceding equation is then written with the effective indices ηθ ^η (Τ) of these modes:

n _p ^eff (Τ) / λρ - ns ^eff (Τ) / λ8 - n _c ^eff (Τ) / λ ₀ = 1 / A

Low loss guides fabricated by diffusion of titanium in PPLN can thus operate as an optical parametric oscillator through external pumping, but with the same limits in terms of accessible wavelengths as solid PPLN. In addition, it is not possible to envisage an integrated electric pumping.

The area of QAP waveguides is less developed in the case of semiconductors. For historical reasons, the majority of the devices described in the literature were aimed at applications in the C band of telecommunications produced in GaAs / GaAlAs guides. At these wavelengths, the required QAP period values and the sizes of the patterns defining the waveguides are typically less than 4 µm and therefore sensitive to many technological imperfections. This results in propagation losses which are too great for satisfactory conversion efficiencies. These limitations have proven to be prohibitive to justify the cost of hybrid integration of a pumping laser diode by one of the known techniques of transfer with a QAP guide, allowing optical coupling and mechanical assembly.

For wavelengths greater than 2 µm, more recent studies have shown that it becomes easier to fabricate low loss QAP waveguides as the characteristic dimensions of the structures increase and become less sensitive to technological imperfections. In such guides produced by epitaxial growth of GaAs / GaAlAs alloys under conditions compatible with the needs of QAP, losses of the order of 1 dB / cm have been obtained. However, these GaAs / GaAlAs materials do not lend themselves to long wavelength pumping.

On the other hand, very recently guides with low loss QAP from gallium antimonide and its alloys have been produced and described in the publication: S. Roux, L. Cerutti, E. Tournié, M. Garcia, B. Gérard, G. Patriarche and A. Grisard, “First orientation-patterned GaSb ridge waveguides fabrication and preliminary characterization for frequency conversion in the mid-infrared,” Proc. SPIE 9894, Nonlinear Optics and its Applications IV, 989415 (April 27, 2016).

These GaSb-based materials have the advantage of a non-linear susceptibility of order 2 of GaSb 50% greater than that of GaAs, and they are transparent from 2 to 20 µm.

FIG. 4 illustrates a guide 20 as described in the abovementioned publication, in section perpendicular to the guide direction Z. The guide layer is made of GaSb, and the guide has two lower confining layers made of Al _x Gai.xAs _y Sbi alloy .y with two different x and y stoichiometries. The upper confinement is achieved by air. The right curve illustrates the spatial confinement of the guided light wave.

The QAP structure is obtained by epitaxy of the AIGaAsSb and GaSb materials from a seed substrate, as illustrated in FIG. 5 and described in the abovementioned publication.

In a first step a) a first stack 40 is produced, comprising a first GaAs 50 substrate of orientation [1,0,0] on which a barrier layer 55 and a thin layer of thickness e close to is epitaxially grown. 0.1 μm also of orientation GaAs [1,0,0] which is turned over to place it in front of a second substrate of GaAs 70 of orientation [1,0,0].

In a second step b) bonding of the stack 40 is carried out on the substrate 70 by molecular adhesion. Alternatively, it is possible to deposit before contacting a layer of S1O2 or a stack of SiN / SiO2 on each surface of GaAs and then to carry out an SiO ₂ / SiO ₂ bonding. The crystallographic orientation of the stack 40 is found reversed with respect to that of the substrate 70.

In a step c) the substrate 50 and the barrier layer 55 are made to disappear by thinning.

In a step d), patterns are produced on the layer 60 by photolithography, then etching through the layer 60 (and possible layers of SiN and S1O2 inserted for bonding). A SubG seed substrate is then obtained consisting of a GaAs slice [1,0,0] locally comprising crystalline zones of inverted GaAs [-1,0,0] of thickness t and of periodicity Λ or any other pattern. meeting QAP needs. The SubG seed substrate, here produced from GaAs, is called in the state of the art ΟΡ-GaAs (for “Orientation-Patterned” in English).

In a final step e) we grow, here by hetero-epitaxy, the layers of AIGaAsSb and the layer of GaSb (not shown) which retain the starting orientation of the substrate-seed, then the specific shape of the guide is produced by engraving, to obtain the QAP 20 guide.

Note that the etching in step d) of the patterns leads to a residual relief of thickness greater than or equal to t (of the order of a hundred nanometers) which can prove to be troublesome from the point of view of optical losses. . It can then be advantageously removed by an additional epitaxial recovery step with or without mechanical-chemical planarization (CMP in English).

There are two coupling modes between the pump laser and the QAP structure.

The most frequent mode connects a pumping laser emitting in free space or coupled in an optical fiber with a QAP guide by means of lenses, or by positioning the QAP guide in front of the pumping fiber.

A second mode is hybridization, consisting in individually reporting a laser diode in front of a waveguide by bonding or any other method allowing both optical coupling and mechanical assembly.

Both routes have limits in terms of pump coupling efficiency and manufacturing cost.

Thus the hybrid laser pump / PPLN hybrid systems and the hybrid laser diode pumping and transfer systems of a QAP guide based on GaAs / GaAlAs alloys have a reduced range of accessible wavelengths, a high cost and difficulties. important if not prohibitive achievements.

An object of the present invention is to remedy the aforementioned drawbacks by proposing a monolithic medium infrared source based on recent technology of QAP waveguides based on GaSb or GaSb alloys.

DESCRIPTION OF THE INVENTION

The subject of the present invention is a device for generating a signal beam having a signal wavelength between 2 and 15 μm, the device comprising:

a multilayer laser source configured to emit a pump beam having a pump wavelength between 1.8 and 5 μm, the laser source comprising an active layer comprising a first material and disposed between at least one upper confinement and injection layer and at least one lower confinement and injection layer, a multilayer optical waveguide with quasi phase agreement, called a guide, the guide comprising a guiding layer called a heart comprising a second material and configured to guide an optical beam along an axis Z, and at least one lower confinement layer placed under the heart,

the first material comprising gallium antimonide or one of its alloys, and the second material comprising gallium antimonide or arsenide or one of their alloys,

the laser source and the guide being coupled so that the pump beam coming from the active layer of the laser source is injected into the core of the guide, the guide layers being produced by epitaxy on a substrate and comprising, according to the Z axis, alternating first zones having a first crystallographic orientation and second zones having an inverted crystallographic orientation with respect to the first crystallographic orientation, so as to transfer energy from the pump beam to the signal beam and a complementary beam by quasi phase agreement,

the layers of the laser source also being produced by epitaxy, thus forming with the guide layers and the substrate a monolithic crystalline block.

Preferably the layers of the laser source, the layers of the guide in the first zones and the substrate have a crystallographic orientation [1, 0, 0], and the layers of the guide in the second zones have a crystallographic orientation [-1, 0, 0] or vice versa.

Preferably, the substrate is chosen from gallium arsenide or gallium antimonide.

According to a first variant, the layers of the guide have a part without alternations of crystallographic orientation and in which the layers of the laser source are produced by epitaxy on said part, the coupling between the laser source and the guide being produced by evanescent waves.

According to one embodiment, to perform the coupling by evanescent waves, the laser source comprises a tip-shaped end so as to present a progressive decrease in its effective index. According to one embodiment, the device according to the invention further comprises a first signal laser diode configured to emit the signal beam and to inject it into the heart of the guide, the guide then operating as an amplifier of the injected signal beam.

According to one embodiment, a respective facet of each end of the layers of the guide has a reflective treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for said signal wavelength.

According to a second variant, the layers of the laser source are produced by epitaxy on a part of the substrate not comprising guide layers, the coupling between the laser source and the guide being carried out directly by aligning the active layer and the core. .

Preferably, the guide layers have a part without alternations of crystallographic orientation and the layers of the laser source are produced by epitaxy in a box hollowed out to the substrate in said part without alternations of crystallographic orientation.

According to one embodiment, the device according to the invention further comprises a second signal laser diode configured to emit the signal beam and to inject it into the heart of the guide, the guide then operating as an amplifier of the injected signal beam, the second signal laser diode being epitaxial on a part of the upper layer of the guide not comprising alternations of crystallographic inversion, the coupling between the second signal laser diode and the guide being carried out by evanescent waves.

According to a first sub-variant there is a space between the laser source and the guide, said space being at least partially filled with a dielectric material.

According to one embodiment, a respective facet of each end of the layers of the guide has a reflective treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for said signal wavelength.

According to a second sub-variant, the layers of the laser source and the layers of the guide form a continuum, a cavity of the laser source then extending between the two ends of said continuum.

According to one embodiment, the ends of the continuum each have a reflective treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for said signal wavelength.

According to another aspect, the invention relates to a method of manufacturing a device for generating a signal beam having a signal wavelength between 2 and 15 μm, comprising the steps consisting in: producing a substrate having a first crystallographic orientation and comprising a first part having periodic reliefs of crystallographic orientation reversed with respect to the first crystallographic orientation, and a second part devoid of reliefs,

making an optical guide with quasi multilayer phase agreement, called a guide, by epitaxy of said layers on the substrate, the guide comprising a guiding layer called a heart configured to guide an optical beam along a Z axis, and at least one layer of lower confinement arranged under the core, the guide layers comprising, along the Z axis and above the first part, an alternation of first zones having a first crystallographic orientation and second zones having an inverted crystallographic orientation relative to the first crystallographic orientation,

making a multilayer laser source by epitaxy of said layers, the laser source being configured to emit a pump beam having a pump wavelength between 1.8 and 5 μm, the laser source comprising an active layer disposed between at least one confinement layer and upper injection and at least one confinement and lower injection layer, the active layer of the laser source comprising a first material comprising gallium antimonide or one of its alloys, the core of the guide comprising a second material comprising gallium antimonide or arsenide or one of their alloys, the laser source and the guide being coupled so that a pump beam from the active layer of the laser source is injected into the core of the guide, the layers of the laser source forming with the layers of the guide and the substrate a monolithic crystalline block.

According to a first variant, the layers of the laser source are produced by epitaxy on the layers of the guide, the method further comprising a step of etching the layers of the laser source to define the laser source above the part of the guide located above of the second part.

According to a second variant, the step of producing the guide layers is followed by a step of making a box by etching said guide layers located above the second part of the substrate. The layers of the laser source are produced by epitaxy in said box and the layers of the laser source are configured so that the coupling between the laser source and the guide is achieved by aligning the active layer and the heart. The method further includes a step of removing excess epitaxial layers.

According to one embodiment, the step of producing the box comprises a step of producing a mask and a step of etching through an opening of the mask.

According to an option, the etching step through an opening of the mask is a dry etching, the box then having vertical or slightly inclined sides

According to one embodiment, the method comprises, after the step of making the box and before the step of epitaxy of the layers of the laser source, a step of depositing a dielectric on the sides of the box.

According to another option, the etching step through an opening is carried out so that the box has inclined sides.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of nonlimiting examples and in which:

Figure 1, already cited, illustrates an artificial non-linear network.

FIG. 2, already cited, gives examples of doublets of wavelengths accessible as a function of the pump wavelength for gallium arsenide with periodic orientation.

FIG. 3, already cited, gives examples of doublets of wavelengths accessible as a function of the pump wavelength for gallium arsenide with periodic orientation (zoom of FIG. 2) and for lithium niobate with periodic polarization.

Figure 4, already cited, illustrates a cross section of a QAP guide according to the state of the art.

FIG. 5, already cited, illustrates the different stages of obtaining a QAP structure from a seed substrate according to the state of the art.

FIG. 6 illustrates a first variant of the device for generating a signal beam according to the invention.

FIG. 7 illustrates a second variant of the device for generating a signal beam according to the invention.

FIG. 7a illustrates an embodiment of the device according to the second variant of the invention.

FIG. 8 illustrates an example of a stack for producing the QAPG guide for the device according to the invention.

FIG. 9 illustrates the different wavelengths of signal As accessible for a pump wavelength λρ of 2 pm or 2.2 pm, as a function of the period A of the crystallographic alternations in a QAPG guide.

FIG. 10 illustrates the starting substrate of the device according to the invention, from which the different layers are epitaxied.

FIG. 11 illustrates a solution for carrying out an evanescent wave coupling between the laser source and the QAPG guide of the “tap” type.

FIG. 12 illustrates a system according to the invention comprising on a same substrate a plurality of devices according to the first variant of the invention.

Figure 13 recalls the three main modes of parametric generation in non-linear optics. FIG. 13a illustrates an OPG operation for “Optical Parametric Generation” in English, FIG. 13b illustrates an OPA operation for “Optical Parametric Amplifier” in English, and FIG. 13c illustrates an OPO operation for “Optical Parametric Oscillator” in English.

FIG. 14 illustrates a device according to the first variant of the invention in the OPG configuration.

FIG. 15 illustrates a device according to the first variant of the invention in OPA configuration according to a first preferred option.

FIG. 16 illustrates a device according to the first variant of the invention in OPA configuration according to another option.

FIG. 17 illustrates a device according to the first variant of the invention in the OPO configuration.

FIG. 18 illustrates a device according to the first embodiment (space between laser source and QAPG guide) of the second variant of the invention in the OPG configuration.

FIG. 19 illustrates a device according to the first embodiment (space between laser source and QAPG guide) of the second variant of the invention in OPA configuration.

FIG. 20 illustrates a device according to the first embodiment (space between laser source and QAPG guide) of the second variant of the invention in the OPO configuration.

FIG. 21 illustrates a device according to the second embodiment (continuum between laser source and QAPG guide) of the second variant of the invention in the OPG configuration.

FIG. 22 illustrates a device according to the second embodiment (continuum between laser source and QAPG guide) of the second variant of the invention in OPA configuration.

FIG. 23 illustrates a device according to the second embodiment (continuum between laser source and QAPG guide) of the second variant of the invention in the OPO configuration.

FIG. 24 illustrates a method of producing a device for generating a signal beam according to another aspect of the invention.

FIG. 25 illustrates a first variant of the method for producing a device for generating a signal beam according to another aspect of the invention, corresponding to the production of the first variant of the device.

FIG. 26 illustrates a second variant of the method for producing a device for generating a signal beam according to another aspect of the invention, corresponding to the embodiment of the second variant of the device.

FIG. 27 illustrates the production of the mask and the etching through the opening of the mask.

FIG. 28 illustrates a first embodiment of the second variant of the method in which the box has vertical or slightly inclined sides.

FIG. 29 illustrates a second embodiment of the second variant of the method in which the box has inclined sides.

FIG. 30 illustrates the structure obtained after the epitaxy step of the laser layers, the structure above the guide being polycrystalline.

FIG. 31 illustrates an embodiment of the first embodiment (vertical or slightly inclined sides of the box) of the second variant of the method, in which a dielectric layer is deposited on the sides of the box.

FIG. 32 illustrates an example of a structure obtained after the step of removing the excess layers.

FIG. 33 illustrates an example of a structure obtained after the epitaxy step of the laser source in a box with inclined sides.

FIG. 34 illustrates an example of a structure obtained after the epitaxy step of the laser source in a box with inclined sides and the step of removing the excess layers.

FIG. 35 illustrates a final device produced according to the second variant of the method.

DETAILED DESCRIPTION OF THE INVENTION

The invention takes advantage of the recent technology of QAP waveguides based on gallium antimonide or one of its alloys as described above, and the fact that this same material (or one of these alloys) allows also the production of laser diodes emitting in a wavelength range 1.8pm-5pm compatible with conversion to higher IR wavelengths.

The device 10 according to the invention, illustrated in FIGS. 6 and 7, is a device for generating a signal beam Bs having a signal wavelength As of between 2 and 15 μm.

It comprises a multilayer LS laser source configured to emit a pump beam Bp having a pump wavelength λρ of between 1.8 and 5 μm. The laser source LS comprises an active layer AL comprising a first material M1 and arranged between at least one upper confinement and injection layer Clsup and at least one lower confinement and injection layer Clinf. The laser source is electrically pumped.

The two functions, carrier injection and optical confinement, can be achieved by a single layer (one on each side). More conventionally, each functionality requires at least one specific layer, either an injection layer and an upper confinement layer, or an injection layer and a lower confinement layer.

The device also includes a QAPG quasi-phase multilayer optical waveguide, referred to as a guide in the following description. The guide comprises a guiding layer GL called the core comprising a second material M2 and configured to guide an optical beam along an axis Z.

The guide also includes at least one lower confining layer Cinf disposed under the heart. An upper confinement layer is not necessary, since guidance can be achieved by air.

The active layer AL and the core GL are spatially separated.

The laser source LS and the guide QAPG are coupled so that the pump beam Bp coming from the active layer AL of the laser source LS is injected into the heart GL of the guide QAPG. Different coupling modes are possible and described below.

The guide layers are produced by epitaxy on a Sub substrate and comprise along the Z axis an alternation of first zones Zi having a first crystallographic orientation and second zones Z ^ having an inverted crystallographic orientation with respect to the first crystallographic orientation, so as to transfer energy from the pump beam Bp to the signal beam Bs and a complementary beam by quasi phase agreement QAP.

In addition, the layers of the laser source are also produced by epitaxy, thus forming with the guide layers and the Sub substrate a monolithic crystalline block.

FIG. 6 describes a first variant of the device 10 according to the invention according to which the layers of the laser source LS are epitaxied on the layers of the guide, the coupling between the laser source and the guide being produced by evanescent waves.

It is therefore here the guide layers which constitute the substrate on which the layers of the laser source are epitaxied.

The pump beam Bp from the active layer AL is coupled by evanescent waves in the heart GL of the guide, and in the guide takes place the energy transfer allowing the signal beam Bs to be generated. The complementary beam also generated is not not shown in Figure 6.

According to one embodiment, the guide layers have a portion without alternations of crystallographic inversion. Preferably, the layers of the laser source LS are epitaxied on this part. The manufacture of the laser source on an area of the substrate free of alternations in crystallography and residual relief eliminates the problems induced by the defects during the growth of the layers.

FIG. 7 describes a second variant of the device 10 according to the invention according to which the layers of the laser source LS are produced by epitaxy on a part of the substrate not comprising layers of the guide. The coupling between the laser source and the guide is carried out directly by aligning the active layer AL and the core GL.

The guide and the laser source here share the same Sub substrate.

The pump beam Bp from the active layer AL is coupled directly into the core GL of the guide, and in the guide takes place the energy transfer allowing the signal beam Bs to be generated. The complementary beam also generated is not shown figure 7.

The direct coupling can take place according to different embodiments described below.

FIG. 7a illustrates an embodiment of this second variant in which the layers of the guide have a part without crystallographic alternation, and the layers of the laser source are produced by epitaxy in a Caisson box hollowed out up to the substrate in this part of the layers of the guide without alternating crystallography (see further in the process section).

The fact that the layers are produced by epitaxy induces specific structural characteristics, allowing the production of a monolithic device.

Epitaxy is a method for growing a crystal by depositing atoms of the chemical elements of the crystal to be produced on the surface of a monocrystalline substrate, chosen so as to have lattice parameters close to those of the desired crystal drop. The crystal gradually forms from the substrate. Typically an epitaxy method is MBE (Molecular Beam Epitaxy in English) or MOVPE (Metal Organic Vapor Phase Epitaxy in English).

Epitaxy allows thin crystalline layers to be deposited on top of each other, the crystalline mesh of an upper layer being almost in agreement with the crystalline mesh of the lower layer. The stacks of thin epitaxial layers thus form a quasi-continuum. This structure cannot be obtained by other deposition methods which result in a structure of the material deposited in grains and not continuous or almost continuous.

Thin layers typically have a thickness ranging from a few nanometers to a few microns. We distinguish homo-epitaxy, which consists in growing a crystal on a substrate of identical chemical nature (for example GaSb on GaSb), and hetero-epitaxy, in which the crystal and the substrate are of different chemical natures ( for example GaSb on GaAs).

The different materials of the layers of the device 10 according to the invention are chosen in order to be able to achieve epitaxial growth. The semiconductor platform used for the guide must be compatible with the growth of an appropriate laser source.

The first material M1 of the active layer AL of the laser source LS comprises gallium antimonide GaSb or one of its alloys. The second material M2 of the guide core at QAPG includes antimony or gallium arsenide GaSb, GaAs or one of their alloys.

Preferably, the QAPG guide comprises gallium antimonide GaSb (or one of its alloys), which has a non-linear susceptibility of order 2 which is 50% greater than that of GaAs and is transparent from 2 to 20 μm. In this case, the laser source and the guide are both based on GaSb (or an alloy thereof).

The materials of the confinement and injection layers of the laser source are adapted according to the material M1 constituting AL.

The material of the at least one confinement layer of the QAPG guide is adapted as a function of the material M2 constituting the core GL.

The device 10 according to the invention is a monolithic component constituting a coherent source of compact IR medium photons. It combines the properties of a pumping laser source with electrical power produced from gallium antimonide and its alloys and a QAPG converter of the wavelength of this source, operating in guided configuration and in principle almost phase agreement, and made from materials such as arsenide or gallium antimonide and their alloys. It has a large number of accessible signal wavelengths, and can therefore be used in a large number of applications, in particular those which exploit the spectroscopic properties of the so-called infrared fingerprint region.

Designed and produced by epitaxial growth, the monolithic device 10 according to the invention offers a better and simpler coupling between a pumping laser source and a non-linear QAP waveguide, which allows improved energy efficiency. Furthermore, its production is compatible with collective production by proven techniques, and therefore at lower cost.

According to one embodiment, the material M1 and / or the material M2 of the guide

QAPG comprises (comprise) a quaternary alloy of gallium antimonide of chemical formula GaXAsSb, the element X being chosen from Aluminum or indium in order to adjust the index and the gap of the alloy according to the function to fill.

For the source, a quaternary alloy is preferred for having different bandgap widths, and therefore being able to produce a hetero-structure with separate confinement.

For the guide, a binary material is preferred for its intrinsically superior quality than that of ternary or quaternary alloys. For a “Taper” type approach, a ternary or quaternary alloy is necessary in order to modify the optical index and therefore the confinement, and to perform coupling by evanescent waves.

According to one embodiment, the substrate is gallium arsenide GaAs. With a GaAs substrate, the QAPG guide having an M2 material based on GaSb or one of its alloys is therefore heteroepitaxied on the GaAs substrate.

According to another embodiment, the substrate is gallium antimonide GaSb. With a GaSb substrate, the QAPG guide having an M2 material based on GaSb or one of its alloys is therefore homoepitaxied on the GaSb substrate, which makes it possible to avoid structural defects and the stresses generated in heteroepitaxial due to the mismatch of mesh parameter between GaSb and GaAs.

An example of a stack for making the QAPG is illustrated in FIG. 8. The material M2 of the core is GaSb doped N at approximately 10 ¹⁶ cm ^-3 , and the QAPG comprises two lower confinement layers Cinf 1 and Cinf2 made of AIGaAsSb alloy, on a Sub substrate in GaSb doped N. This structure is compatible with the growth by homo-epitaxy of a laser source based on GaSb or an alloy, or on the core of the guide (without alternations) in GaSb (first variant described in Figure 6), or on the substrate itself also in GaSb (second variant described in Figure 7).

FIG. 9 illustrates the different signal wavelengths As accessible for a pump wavelength Ap of 2 μm or 2.2 μm, as a function of the period A of the crystallographic alternations.

Preferably, the layers of the laser source AL, Clinf, Clsup, the guide layers in the first zones Zi and the Sub substrate have a crystallographic orientation [1,0,0], and the guide layers in the second zones Zi have a crystallographic orientation [-1,0,0] or vice versa.

The starting substrate Sub of the device 10 from which the different layers are epitaxied is illustrated in FIG. 10. A first part P1 corresponds to the substrate SubG as illustrated in FIG. 5d, with an orientation substrate [1,0,0] on which has reliefs in orientation [-1, 0.0], It is for example an OP-GaAs (“Orientation Patterned”, see above) or an OP-GaSb. A second part P2 corresponds to the substrate devoid of reliefs.

The starting Sub substrate can be semi-insulating or doped according to the design choices of the electrically pumped structures.

When the substrate is insulating, it is necessary to make the contacts of the laser on the front face, which is not the case when the Sub substrate is doped, contact can be made on the rear face of the substrate.

The epitaxy repeats necessary for the production of a device according to the invention are carried out under conditions which preserve the crystalline orientation of the starting substrate. It can be, as explained above, homo-epitaxy or hetero-epitaxy.

The guide layers are first epitaxial on this substrate and will have a part without alternation and a part with alternation of crystallographic orientation.

Subsequently, the laser source is epitaxied either on the part of the guide layers without alternation (first variant illustrated in FIG. 6) or directly on the part of the substrate without alternation, the guide layers having been previously removed (second variant illustrated in FIG. 7) .

The different variants of the method for producing the device according to the invention are described below.

According to one embodiment, the active layer AL of the laser source comprises multi-quantum wells MPQ (MQW in English for Multi Quantum Well) based on said quaternary alloy of gallium antimonide of chemical formula GaXAsSb, element X being chosen from Aluminum (Al) or Indium (In). MPQ lasers have lower threshold current densities than standard laser diodes.

Preferably, the multilayer laser source is chosen from a laser diode, an inter-band cascade laser and a quantum cascade laser.

According to one embodiment, the guide comprises at least one layer disposed on the side of the heart GL opposite the substrate, the layer furthest from the heart on the side opposite the substrate being called the upper layer Csup. This (or these) upper layer (s) can be an optical confinement layer. Furthermore, when the core is a quaternary alloy with aluminum, it is necessary to encapsulate the latter in order to avoid contact with the air.

A first solution for coupling the evanescent waves of the first variant consists in using a simple coupling between an upper waveguide (pump laser source) and the non-linear QAP guide. This coupling is designed to maximize the transfer of pump power after a distance compatible with the typical lengths of active areas of the laser diodes.

A second coupling solution using evanescent waves, shown diagrammatically in FIG. 11, uses a “type” approach in English, more robust from the point of view of sensitivity to deviations linked to technology.

In this approach, the effective index of the upper waveguide (LS pump laser source) is progressively reduced by changing its geometry (tip-shaped end) so as to make it ultimately lower than the effective index of the non-waveguide. -linear to QAP, which makes it possible to transfer the optical power of the pump, going from region A to region C, most of the time from the laser guide LS to the guide QAPG.

The main condition for ensuring efficient transfer is that the effective index of the laser guide, of the order of 3.79 for a laser diode made of antimony materials optimized at 2 pm, is sufficiently greater than that of the guide to QAP. This prohibits the use of a GaSb core. The guide to QAP can then be produced in quaternary materials GaXAsSb, in ternary materials GaXSb with X chosen from Al or In, or in GaAs / GaAlAs.

An advantage of the first variant is that, the laser source being epitaxial on the guide, the entire device 10 can be produced in a single epitaxy.

Following the collective manufacturing steps, individual components are obtained by cleavage of the facets.

It is possible to take advantage of the two-layer nature of the device according to the invention according to the first variant to integrate more complex functions.

According to one embodiment, the device 10 comprises a plurality of laser sources having substantially identical pump wavelengths, and a first combiner configured to combine all of the pump beams coming from the different laser sources in a single pump beam, which is injected into the same guide at QAP.

The dual-layer nature of the device according to the first variant also makes it possible to combine the signal wavelengths produced in several wavelength converters electrically pumped to a single medium-infrared waveguide. Thus according to an embodiment illustrated in Figure 12 the invention relates to a system 100 comprising on the same substrate a plurality of devices 10-1, 10-2, ... according to the first variant, each device being configured to generate a signal beam Bs1, Bs2, ... of associated signal wavelength As1, As2, ... and comprising a second Comb2 combiner configured to combine all of the signal beams in a single beam.

The second variant of the device 10 illustrated in FIG. 7 consists of a co-planar integration of the pumping laser source and the guide, coupled by direct coupling. This direct coupling consists in aligning the mode of the guide to

QAP with the active guide mode of the laser source in the structure, optimizing the overlap between the two.

The laser source is epitaxied in a box in a second step, after epitaxy of the QAPG guide and etching of the box, under conditions which allow the end-to-end coupling with the guide.

For the production of a device illustrated in FIG. 7, two epitaxies are therefore necessary: the first produces the layers necessary for the waveguide at QAP, the second takes place in an etched box in which the layers necessary for the laser source are epitaxied. .

The example of QAPG guide as described in FIG. 8 is compatible with this second variant.

Concerning the morphology of the caissons, according to a first embodiment they are with straight sides, and according to a second embodiment they are inclined to facilitate the second resumption of epitaxy (see below).

This second variant configuration of the device according to the invention offers, in addition to those of the first variant, several advantages:

- A greater choice of design parameters for the laser source is offered, in particular with regard to making electrical contacts, since it is no longer constrained by the design stages of the evanescent couplers.

-The direct coupling of the active guide from the diode to the QAP guide is easier than the evanescent coupling of the first variant, and potentially less sensitive to variations in the pumping wavelength.

The shape of the boxes induces structural characteristics of the device according to the invention according to the second variant.

According to the first embodiment, the box is on straight sides. Typically there is a space between the laser source and the guide, this space being at least partially filled with a dielectric material matD (see Figures 18 to 20 below).

According to the second embodiment with an inclined box, a preferred variant is that the layers of the laser source and the layers of the guide form a continuum, the cavity of the laser source then extending between the two ends of the continuum (see below). Figures 21 to 23).

The monolithic nature of the device 10 according to the invention also allows the parametric generation of the signal beam Bs according to different architectures from the point of view of non-linear optics, to lead to competitive sources in the mid-infrared.

FIG. 13 shows the three main modes of parametric generation by a component 90 in non-linear optics.

FIG. 13a illustrates an OPG operation for “Optical Parametric Generation” in English as described and illustrated in FIG. 1, without feedback.

FIG. 13b illustrates an OPA operation for “Optical Parametric Amplifier” in English, in which a laser diode signal DLs supplies a beam at the signal frequency which is amplified in the component 90, without feedback.

FIG. 13c illustrates an OPO operation for “Optical Parametric Oscillator” in English, in which the component 90 is placed in an oscillating cavity for the wavelength signal As, allowing a resonant effect at this wavelength (with feedback) .

Following the collective manufacturing steps, individual components according to the invention are obtained by cleavage of the facets and optimized for OPG, OPA or OPO operation. In the figures that follow, the QAPG guide includes an additional layer Csup above the core, which can perform various functions (see above).

Figures 14 to 17 illustrate a device according to the first variant of the invention in the various optical configurations mentioned above. The LS laser source has facets treated with high reflection for the pump wavelength.

Figure 14 illustrates the OPG configuration as described in Figure 6.

FIGS. 15 and 16 illustrate the configuration OPA in which the device 10 further comprises a first signal laser diode DL1s configured to emit the signal beam Bs and to inject it into the heart of the guide GL, the guide then operating as an amplifier of the signal beam injected.

FIG. 15 illustrates a first preferred variant in which the first DL1s signal laser diode is epitaxied on a part of the upper layer of the guide not comprising alternations of crystallographic inversion. The coupling between the first DL1s signal laser source and the guide is carried out by evanescent waves.

FIG. 16 illustrates another variant in which the source DL1s is not part of the monolithic block and is arranged outside.

FIG. 17 illustrates the configuration OPO in which the respective facet of each end of the layers of the guide has a reflecting treatment configured to at least partially reflect the signal wavelength As so as to produce an amplifying cavity for this signal wavelength .

The facet on the side opposite the exit of Bs has a highly reflective treatment HR1 while the facet on the exit side of Bs has a partially reflective treatment to let out a fraction of the signal beam.

Figures 18 to 20 illustrate a device according to the first embodiment (with space between LS and QAPG) of the second variant of the invention (coplanar integration), in the different optical configurations mentioned above. The LS laser source has facets treated with high reflection for the pump wavelength.

FIG. 18 illustrates the OPG configuration, the space between the laser source LS and the guide QAPG is at least partially filled with a dielectric material MatD.

FIG. 19 illustrates the configuration OPA, in which the device 10 further comprises a second signal laser diode DL2s configured to emit the signal beam Bs and to inject it into the heart of the guide, the guide then operating as an amplifier of the signal beam injected. The second DL2s signal laser diode is epitaxial on a part of the upper layer of the guide not comprising alternating crystallographic orientations, the coupling between the second signal laser diode and the wave guide being carried out by evanescent waves.

FIG. 20 illustrates the OPO configuration in which the respective facet of each end of the layers constituting the guide has a reflective treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for this wavelength . The facet opposite the exit of Bs has a highly reflective treatment while the facet on the exit side of Bs has a partially reflective treatment to let out a fraction of the signal beam.

Figures 21 to 23 illustrate a device according to the second embodiment (continuum between LS and QAPG) of the second variant of the invention (coplanar integration), in the different optical configurations mentioned above.

The cavity of the LS laser source extends between the two ends of the continuum, these two ends therefore presenting a highly reflective treatment for the pump wavelength.

Figure 21 illustrates the OPG configuration.

FIG. 22 illustrates the configuration OPA in which the device 10 further comprises a second signal laser diode DL2s configured to emit the signal beam Bs and to inject it into the heart of the guide. The guide then operates as an amplifier of the injected signal beam. The second DL2s signal laser diode is epitaxial on a part of the upper layer of the guide not comprising alternations of crystallographic inversion, the coupling between the second signal laser diode and the guide being carried out by evanescent waves.

FIG. 23 illustrates the configuration OPO in which the ends of the continuum each have, in addition to the reflective treatment at λρ, a reflective treatment configured to at least partially reflect the signal wavelength As, so as to produce an amplifying cavity for this wave length.

According to another aspect, the invention relates to a method 80 for manufacturing a device for generating a signal beam Bs having a signal wavelength As of between 2 and 15 μm illustrated in FIG. 24.

The first step 100 produces a Sub substrate having a first crystallographic orientation and comprising a first part P1 having periodic reliefs of reverse crystallographic orientation with respect to the first crystallographic orientation, and a second part P2 devoid of reliefs, as described above.

In a second step 200, a multilayer QAPG quasi-phase optical guide, called a guide, is produced by epitaxy of said layers on the substrate Sub. The guide includes a guiding layer called the GL core configured to guide an optical beam along a Z axis, and at least one lower confining layer Cinf disposed under the heart.

The guide layers comprise, along the axis Z and above the first part P1, an alternation of first zones Zi having a first crystallographic orientation and of second zones Zi having an inverted crystallographic orientation with respect to the first crystallographic orientation, as previously described.

In a third step 300, a multilayer LS laser source is produced by epitaxy of said layers, the laser source being configured to emit a pump beam Bp having a pump wavelength Ap of between 1.8 and 5 μm, the laser source comprising an active layer AL disposed between at least one upper confinement and injection layer Clsup and at least one lower confinement and injection layer Clinf, as described above.

The active layer of the laser source comprises a first material M1 comprising GaSb or one of its alloys. The core of the guide comprises a second material M2 comprising GaSb or GaAs or one of their alloys.

The laser source and the guide are coupled so that a pump beam Bp from the active layer AL of the laser source is injected into the core GL of the guide, the layers of the laser source forming with the layers of the guide and the substrate Under a monolithic crystal block.

The production of all the layers by epitaxy from the Sub substrate makes it possible to obtain a simplified process while producing good quality LS and QAP Guide components. The stacks of thin epitaxial layers thus form a quasi-continuum which cannot be obtained by other deposition methods, which result in a structure of the material deposited in grains and not continuous or quasi-continuous.

To make a device 10 according to the first variant, the method, illustrated in FIG. 25, has the following specificities.

During step 300, the layers of the laser source LS are produced by epitaxy on the guide layers. During epitaxy, the LS layers extend over the entire upper surface of the guide. The method therefore comprises a step 400 of etching the layers of LS to define the component LS on the part of the guide located above P2, not comprising alternations and removing the excess LS layers on at least the part of the guide located above P1.

With a type of coupling, step 400 also includes the definition of the tip.

To make a device 10 according to the second variant, the method 80 illustrated in FIG. 26 has the following specificities. The step 200 of making the layers of the QAPG guide is followed by a step 250 of making a box caisson by etching said layers of the guide located above the part P2 of the substrate Sub. The layers of the laser source LS are then produced by epitaxy in the box caisson. At least one thickness of a layer of the laser source is configured so that the coupling between the laser source and the guide is achieved by aligning the active layer AL and the core GL. The method 80 further comprises a step 350 of removing the excess epitaxial layers outside the box.

According to a preferred embodiment, the step 250 of producing the box comprises a step 252 of producing a mask Ma and an etching step 254 through an opening Op of the mask, located in the part above P2 .

FIG. 27 illustrates the production of the mask and the etching through the opening Op. Typically the mask is produced using a resin or a dielectric / metal multilayer, the opening being produced by photolithography.

According to a first embodiment illustrated in FIG. 28, the step 254 of etching through the opening Op of the mask is a dry etching, the box then having vertical or slightly inclined sides 18. Typically, an Inductively Coupled Plasma (ICP) type engraving or a Reactive Ion Etching (RIE) type engraving can produce such flanks.

According to a second embodiment illustrated in FIG. 29, step 254 of etching through an opening Op of the mask is an anisotropic wet etching, the box then having inclined flanks 19. Dry etching can also produce such flanks by an appropriate choice of etching parameters and mask.

Optionally, a stop layer CA2 has been deposited between the substrate Sub and the first lower confinement layer of the Cinfl guide, as illustrated in FIGS. 27 to 29, so that it is possible to stop the etching of the well 254 on the surface of the substrate.

If this CA2 layer is not present, the substrate will itself be slightly etched.

At the end of step 300 of making the LS layers, the epitaxial layers are present in the box but also above the upper layer of the QAPG guide, which can be either GL or a Csup layer as described above.

For the case of a box with straight sides, the laser structure Poly produced above the guide is poly-crystalline, as illustrated in FIG. 30. The laser stack comprises in this example a contact layer of type n CCn, a layer Clinf containment and lower injection layer, an AL active layer, a Clsup upper containment and injection layer and a CCp p-type contact layer. The thickness of CCn is adjusted to align the active layer of the laser and the core of the guide. The electrical properties of

CCp and CCn are chosen to make a good electrical contact by depositing a metal on it.

Step 350 consists in removing this excess Poly structure.

A first option is for example to leave the mask Ma during the epitaxy of LS, step 350 being a step of selective attack of the mask making it possible to carry out the "lift-off" of the excess material.

A second option is to remove the mask before step 300, but before depositing the mask deposited on the upper layer of the guide, a stop layer CA1 monocrystalline. During epitaxy 300 CA1 is covered with monocrystalline materials this time. These materials are then removed on the top of the guide by selective attack (under-etching) of CA1 or by attack until CA1 having previously protected the box.

A third option is to remove the mask before step 300 without the presence of CA1. In this case, the excess monocrystalline materials are eliminated, after protection of the box, by precisely controlling the etching process in order to stop it as soon as the upper layer of the GL guide is reached. This stopping can be facilitated by the insertion in step 300 of a stopping layer CA3 under the laser structure LS.

According to an embodiment of the second variant, the method comprises, after the step of making the well 250 and removing the mask and before the step 300 of epitaxy, a step 270 of depositing a dielectric MatD on the sides of the box as illustrated in FIG. 31. This layer provides an optical interface between the laser source LS and the QAPG guide and optionally makes it possible to protect the heart GL when it contains aluminum.

An example of a structure obtained after step 350 is illustrated in FIG. 32. The dielectric material here fills the space between LS and the QAPG guide.

The active layer AL is defined as corresponding to the emitting layer surrounded by the two optical layers defining the optical cavity.

In addition, by mastering an epitaxial type of "butt-joint" it is possible to obtain a structure without any space between LS and the QAPG guide.

FIG. 33 illustrates an example of a structure obtained after step 300 of epitaxy in a box with inclined sides. Naturally, the layers of the laser extend continuously over the top of the QAPG guide and form a continuum with the layers of the guide.

FIG. 34 illustrates an example of a structure with a box with inclined sides after step 350, once the excess material has been removed.

These structures have the advantage of an excellent injection of the optical mode from AL to GL, and the sides of the Cinf layers are protected with AL.

For both variants, once the epitaxy has been carried out and the excess layers present following this epitaxy have been removed, conventionally the process for producing the final component comprises the steps described below. FIG. 35 illustrates a final device produced according to the second variant of the method.

-realization of the contact p (metallic) Contp and definition of the StrL laser ribbon, -realization of the contact n Contn on the front / upper face (as illustrated in Figure 35) by etching to CCn along the laser ribbon, guide StrG - thinning of the substrate,

-realization of a contact n on the rear face if not made on the front face, -cleavage on the "left" laser face and on the "right" laser face or etching to define the final component.

Claims (21)

1. Device (10) for generating a signal beam (Bs) having a signal wavelength (As) of between 2 and 15 μm, the device comprising: a multilayer laser source (LS) configured to emit a pump beam (Bp) having a pump wavelength (Ap) between 1.8 and 5 μm, the laser source comprising an active layer (AL) comprising a first material (M1 ) and arranged between at least one upper confinement and injection layer (Clsup) and at least one lower confinement and injection layer (Clinf), -a multilayer quasi-phase agreement optical waveguide (QAPG), called a guide, the guide comprising a guiding layer called a core (GL) comprising a second material (M2) and configured to guide an optical beam along a Z axis, and at least one lower confinement layer (Cinf) placed under the core, the first material (M1) comprising gallium antimonide (GaSb) or one of its alloys, and the second material (M2) comprising antimony or gallium arsenide (GaSb, GaAs) or one of their alloys, the laser source (LS) and the guide (QAPG) being coupled so that the pump beam (Bp) coming from the active layer (AL) of the laser source (LS) is injected into the core (GL) of the guide ( QAPG) the layers of the guide being produced by epitaxy on a substrate (Sub) and comprising, along the Z axis, an alternation of first zones (Zi) having a first crystallographic orientation and second zones (Z_i) having a crystallographic orientation reversed by relative to the first crystallographic orientation, so as to transfer energy from the pump beam (Bp) to the signal beam (Bs) and a complementary beam by quasi-phase agreement, the layers of the laser source also being produced by epitaxy, thus forming with the guide layers and the substrate (Sub) a monolithic crystalline block. 2. Device according to claim 1 in which the layers of the laser source (AL, Clinf, Clsup), the layers of the guide in the first zones (Ζ _Ί ) and the substrate (Sub) have a crystallographic orientation [1, 0, 0], and in which the guide layers in the second zones (Z ^) have a crystallographic orientation [-1, 0, 0] or vice versa. 3. Device according to one of the preceding claims wherein the substrate is selected from gallium arsenide (GaAs), or gallium antimonide (GaSb). 4. Device according to one of the preceding claims in which the guide layers have a part without alternations of crystallographic orientation and in which the layers of the laser source (LS) are produced by epitaxy on said part, the coupling between the source laser (LS) and the guide being produced by evanescent waves. 5. Device according to claim 4 wherein, to achieve the coupling by evanescent waves, the laser source comprises a tip-shaped end so as to present a gradual decrease in its effective index. 6. Device according to one of claims 4 or 5 further comprising a first laser signal diode (DL1s) configured to emit the signal beam (Bs) and to inject it into the heart of the guide, the guide then operating as an amplifier of the injected signal beam (OPA). 7. Device according to one of claims 4 to 6 wherein a respective facet of each end of the guide layers has a reflective treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for said signal wavelength (OPO). 8. Device according to one of claims 1 to 3 wherein the layers of the laser source (LS) are produced by epitaxy on a part of the substrate not comprising guide layers, the coupling between the laser source and the guide being performed directly by aligning the active layer (AL) and the core (GL). 9. Device according to the preceding claim in which the guide layers (QAPG) have a portion without alternations of crystallographic orientation (Z1, Zi) and in which the layers of the laser source are produced by epitaxy in a hollowed-out box (Box) to the substrate in said part without alternations of crystallographic orientation. 10. Device according to one of claims 8 or 9 further comprising a second signal laser diode (DL2s) configured to emit the signal beam (Bs) and to inject it into the heart of the guide, the guide then operating as an amplifier of the injected signal beam (OPA), the second signal laser diode being epitaxial on a part of the upper layer of the guide not comprising crystallographic inversion alternations, the coupling between the second signal laser diode and the guide being carried out by waves evanescent. 11. Device according to one of claims 8 to 10 wherein there is a space between the laser source and the guide, said space being at least partially filled with a dielectric material. 12. Device according to one of claims 8 to 9 wherein a respective facet of each end of the guide layers has a reflective treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for said signal wavelength (OPO). 13. Device according to one of claims 8 to 10 wherein the layers of the laser source and the layers of the guide form a continuum, a cavity of the laser source then extending between the two ends of said continuum. 14. Device according to claim 13 wherein said ends of said continuum each have a reflecting treatment configured to at least partially reflect the signal wavelength, so as to produce an amplifying cavity for said signal wavelength (OPO). 15. Method for manufacturing a device for generating a signal beam (Bs) having a signal wavelength (λs) of between 2 and 15 μm, comprising the steps consisting in: -realize (100) a substrate (Sub) having a first crystallographic orientation and comprising a first part (P1) having periodic reliefs of crystallographic orientation reversed with respect to the first crystallographic orientation, and a second part (P2) devoid of reliefs , -making (200) a multilayer quasi-phase agreement (QAPG) optical guide, called a guide, by epitaxy of said layers on the substrate (Sub), the guide comprising a guiding layer called a heart (GL) configured to guide an optical beam the along a Z axis, and at least one lower confinement layer (Cinf) disposed under the core, the guide layers comprising, along the Z axis and above the first part (P1), an alternation of first zones (Z0 having a first crystallographic orientation and second zones (Z.î) having an inverted crystallographic orientation compared to the first crystallographic orientation, -realize (300) a multilayer laser source by epitaxy of said layers, the laser source being configured to emit a pump beam (Bp) having a pump wavelength (λρ) between 1.8 and 5 pm, the laser source comprising a layer active (AL) disposed between at least one upper confinement and injection layer (Clsup) and at least one lower confinement and injection layer (Clinf), the active layer of the laser source comprising a first material (M1) comprising gallium antimonide (GaSb) or one of its alloys, the core of the guide comprising a second material (M2) comprising gallium antimonide or arsenide (GaSb, GaAs) or one of their alloys, the laser source and the guide being coupled so that a pump beam (Bp) originating from the active layer (AL) of the laser source is injected into the core (GL) of the guide, the layers of the laser source forming with the guide layers and substrate (Sub) a monolithic crystal block. 16. The method (80) according to claim 15 wherein the layers of the laser source (LS) are produced by epitaxy on the guide layers, the method further comprising a step (400) of etching the layers of the laser source to define the laser source above the part of the guide located above the second part (P2). 17. The method (80) according to claim 15 in which the step of producing (200) the guide layers is followed by a step (250) of making a box (box) by etching said guide layers located at the above the second part (P2) of the substrate, in which the layers of the laser source (LS) are produced by epitaxy in said box (Box), the layers of the laser source being configured so that the coupling between the laser source and the guide is produced by aligning the active layer (AL) and the heart (GL), and further comprising a step (350) of removing the excess epitaxial layers. 18. The method of claim 17 wherein the step of making the box (250) comprises a step of making a mask (252) and an etching step (254) through an opening (Op) of the mask . 19. The method of claim 18 wherein the step (254) of etching through an opening (Op) of the mask is a dry etching, the box (Box) then having sides (18) vertical or slightly inclined 20. The method of claim 19 comprising, after the step of making the well (250) and before the step (300) of epitaxy of the layers of the laser source (LS), a step (270) of depositing a dielectric (MatD) on the sides (18) of the box. 21 Method according to one of claims 17 or 18 wherein the step (254) of etching through an opening (Op) is performed so that the box has inclined sides (19).