Interferometric gain laser equipment

Abstract

A laser device adapted for emitting coherent optical radiation is described, characterized in that the laser device comprises a beam amplifier system, an optical return path for the light beam emerging from the amplifier system, the beam amplifier system comprising a single interferometric optical amplifying device or a plurality of interferometric optical amplifying devices connected in series, and a radiation output element arranged to extract a portion of the light beam emerging from the amplifier system and to transmit the extracted portion of the light beam as output radiation of the laser device.

Description

Technical Field

[0001] The present invention relates to laser devices, and in particular, but not exclusively, to semiconductor laser devices. Background Art

[0002] One of the main limitations of this particular class of lasers is that it is not possible to obtain high optical powers above tens of watts (eg, in the order of kilowatts or more) from a single laser diode.

[0003] This power is necessary in certain industrial processes, for example, in particular in the industrial processing of materials and in the industrial processing of metal sheets and profiles, where the laser is used as a thermal tool for a variety of applications that depend on the interaction parameters of the laser beam with the material being processed (in particular the energy density per unit volume of the laser beam incident on the material) and the interaction time interval.

[0004] For example, a hardening process is performed by directing a low energy density (on the order of tens of watts per square millimeter of surface) on a metal material for a long time (on the order of seconds), while a photoablation process is performed by directing a high energy density (on the order of tens of megawatts per square millimeter of surface) on the same metal material for a time on the order of femtoseconds or picoseconds. Control of these parameters allows for the execution of welding, cutting, drilling, engraving, and marking processes in an intermediate range of increasing energy density and decreasing processing time.

[0005] Laser devices are also used for additive processes, in which the material is supplied, for example, in the form of a filament or as a powder ejected from a nozzle, or it can be present in the form of a powder bed, whereby the material is melted by laser radiation and a three-dimensional print is obtained after resolidification of the material.

[0006] In the prior art, in order to obtain high optical power of the above magnitude, a combination of different laser beams is used.

[0007] Different laser beams can be combined by different techniques based on the respective associations of the laser emitting devices, such as combining mutually incoherent beams (incoherent combining), combining wavelength beams, and combining mutually coherent beams (coherent combining).

[0008] Unfortunately, the radiance of the total beam obtained by incoherent beam combining (taking into account the magnitude of the total optical power and the resulting beam quality) does not exceed that of a single laser. Furthermore, in incoherent combining techniques, there is no relationship between the beams involved (neither phase nor spectrum), so the optical power increases with the number of laser emitting devices involved, at the expense of the quality of the overall beam obtained.

[0009] By wavelength beam combining or coherent beam combining, the emitted optical power can be increased while keeping the quality of the resulting beam constant, and the radiance increases linearly with the number of combined laser emitting devices.

[0010] In particular, in wavelength beam combining (WBC), each laser emitter operates at a different wavelength, and the use of dispersive optical elements allows the beams to be combined, thereby increasing power at the expense of the beam's spectral quality.

[0011] On the other hand, in a coherent beam combining architecture, all laser emitting devices operate at the same wavelength and have a specific phase relationship so that constructive interference may occur between the individual beams.

[0012] The use of one of the mentioned technologies depends on the application requiring high optical power.

[0013] In order to create a highly luminous source of the type used, for example, in laser processing of materials, it is necessary to employ either wavelength or coherent beam combining architectures. Of these, the former is currently the most common solution, primarily due to its greater ease of implementation. Indeed, while there are techniques for combining different laser beams (i.e., beams delivered by different laser emitting devices), the main difficulty in creating a coherent beam combining architecture lies in actively controlling the phase relationships necessary to achieve constructive interference between the various beams involved.

[0014] This difficulty is exacerbated for semiconductor laser devices, where thermal instabilities and nonlinear phenomena can significantly alter the phase of the beam. Summary of the Invention

[0015] The object of the present invention is to provide an alternative solution to existing architectures of laser devices and systems, which solution is simple to manufacture and is capable of emitting a coherent light beam of high optical power.

[0016] In particular, it is an object of the present invention to provide a robust and easy-to-manufacture laser device which allows the maximum power that can be extracted from the semiconductor laser to be increased with respect to the prior art.

[0017] According to the invention, this object is achieved by a laser device having the features specified in claim 1 .

[0018] Particular embodiments form the subject matter of the dependent claims, whose content is to be understood as an integral part of the present description.

[0019] In summary, the present invention is based on the arrangement of an optical amplifier system (i.e., an optical gain device) within a single optical resonant structure (e.g., a resonant cavity (including a Fabry-Perot cavity) or an optical ring path), so that the laser device of the present invention comprises a single transmitting device rather than a combination of multiple transmitting devices. The gain device comprises one or more amplifier stages connected in series or cascade, each amplifier stage comprising an interferometric optical amplification device (i.e., an optical device) that first splits an incident light beam into a pair of sub-beams, then guides the two sub-beams through an amplified branch and an undisturbed propagation branch (i.e., without amplification), and finally combines them into an interferometric light beam. The splitting of the incident light beam is achieved by directing most of the power of the incident light beam toward the non-amplified propagation branch.

[0020] In a currently preferred embodiment, the amplification branch comprises a semiconductor optical amplifier powered by an injected current to achieve a population inversion condition for charge carriers confined in the active region, whereby subsequent radiative recombination and coherent photon emission occur in phase with the passing photons of the incident light beam. Advantageously, splitting the light beam allows for a reduction in the power entering the semiconductor optical amplifier. This reduces various issues associated with circulating power, such as damage to the semiconductor surface, thermal issues associated with any power absorption, and nonlinear phenomena, relative to standard amplifiers, given the same injected current. This configuration allows for devices with higher reliability and a longer average lifetime.

[0021] The optical path returning the interference beam to the input of the gain device forms a resonant structure with the amplifier system, for example in the form of a resonant cavity or resonant ring circuit. The beam propagation can occur in a single propagation direction or in two propagation directions.

[0022] In a currently preferred embodiment with light transmission in free space, an amplifier stage comprising one or more interferometric optical amplification devices comprises beam splitting and combining means (e.g., optical devices implemented as prisms or semi-transparent mirrors) located at the input and output of each interferometric optical amplifier stage, respectively, and a return optical path comprises a reflective and refractive optical system suitable for guiding and spatially shaping the light beam. Alternatively, in an embodiment of guided or integrated optics, the light beam is guided by confinement in optical guides obtained on a substrate (e.g., a substrate compatible with the implementation of semiconductor optical amplifiers), and the light beams are split and recombined by the beam splitting and combining means obtained by means of controlled modal coupling techniques between the aforementioned optical guides.

[0023] The advantage of the interferometric amplifier structure is the possibility of diverting a portion of the incident optical power from the amplifying branch, in such a way as to prevent the occurrence of saturation states in the active region of the optical amplifier, which would limit the amplification characteristics of the optical amplifier.

[0024] Semiconductor interferometric optical amplifiers (SIAs) can exhibit lower gain but higher saturation power than a single SIA. The behavior of an interferometric amplifier deviates increasingly from that of a single amplifier because the larger the portion of the incident beam directed through the non-amplified propagation branch, the greater the gain through the amplifying branch operating away from the saturation point. Furthermore, there are fewer power-related phenomena that degrade the overall performance of the device, resulting in greater stability and a longer lifetime.

[0025] In the above-described amplifier system configuration, a portion of the combined beam emerging from the beam combiner is extracted from the beam combiner at the output of the last interferometric optical amplifier stage and transmitted as the output radiation of the laser device of the present invention, while the remaining portion of the combined beam circulates within the resonant structure to generate laser oscillations. Therefore, in this design, the beam combiner also serves as an output coupler for the resonant structure. For example, the portion of the beam emerging from the amplifier system that is transmitted as output laser radiation represents a loss beam from the beam combiner, so the majority of the combined beam emerging from the amplifier system is reintroduced into the amplifier system and amplified again.

[0026] In an alternative embodiment, an output coupler device is arranged at one end of the optical return path of the interfering light beam (at the input of the amplifier system (of the gain device)) and is obtained as a beam splitting device, which is suitable for extracting a minimum part of the light beam from the light beam circulating in the resonant structure in order to transmit the minimum part of the light beam as output laser radiation.

[0027] The portion of the beam that contributes to the radiation output of the laser device (i.e., relative to the circulating power P b , as the laser output P out The percentage of optical power extracted) is related to the circulating power through the reflectivity parameter R of the output coupler device. Depending on the position of the output coupler device in the resonant structure, it can be

[0028] P out =R·P b

[0029] Or, vice versa,

[0030] P out =(1-R)·P b

[0031] In general, the optimal value of R depends on the characteristics of the resonant structure, in particular the losses experienced by the light beam during its propagation.

[0032] The configuration subject of the present invention allows to obtain a stable balance between loss (output of the laser device), gain and interference between the recombined beams in each interferometric optical amplification device. The splitting ratio of the beam splitting device and the optical lengths of the corresponding amplifying and non-amplifying propagation branches of each interferometric device are selected and controlled in such a way as to optimize the overall performance of the device, including the spectral separation between the interference maxima between the recombined beams. In fact, under actual construction and operating conditions, in the case where the optical path difference between the two branches is not zero, an interference spectrum is generated between the combined beams, and the power of the combined beam corresponds to the average value between the maximum and minimum values ​​of the interference beam power. The spectral separation between the two maxima or two minima of the interference depends on the difference in the optical paths traveled by the two interfering beams.

[0033] In theory, by stabilizing the resonant structure—that is, by forcing the phase difference between the beams propagating through the amplifying branch and the unamplified propagating branch to zero—the performance of a single interferometric amplification device can be equal to (or even exceed) that of a standard non-interferometric laser diode (i.e., an external-cavity semiconductor laser diode). In practice, with an external-cavity semiconductor laser diode, a reduction in the power applied to the gain device can be achieved. Since this operates in the saturation regime, the gain is greater under operating conditions with lower incident optical powers.

[0034] Results of simulations performed by the inventors have shown that the power output from a laser device according to the invention having two gain interference levels is greater than the (incoherent) sum of the powers of two separate laser devices, and more generally, that the power output from a laser device according to the invention at n interference gain levels is greater than the (incoherent) sum of the powers of n separate laser devices.

[0035] Advantageously, the proposed design makes it possible to obtain a coherent beam of high optical power without having to implement difficult techniques for controlling the phase of each laser-emitting device. However, this would allow for further increases in power and a narrower emission band by employing frequency stabilization techniques to actively control the phase of the beam during propagation in real time, for example, by applying control over the phase in the gain device or by creating a delay line, or by employing Pound-Drever-Hall stabilization, which forces oscillations of a single wavelength corresponding to the maximum interference between the beams of the amplified and non-amplified branches into the resonant structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further features and advantages of the invention will emerge in more detail from the following detailed description of an embodiment given by way of non-limiting example with reference to the accompanying drawings, in which:

[0037] Figure 1 is a schematic diagram of a laser device according to the present invention;

[0038] Figure 2 is a first schematic embodiment of a laser device according to the invention having a single interferometric optical amplification device in a free-space embodiment;

[0039] Figure 3 Shown Figure 2 A variant embodiment of the laser device;

[0040] Figure 4 yes Figure 3 A simulation diagram of the behavior of the laser device;

[0041] Figure 5 shows a device with two cascaded interferometric optical magnifications Figure 3 A variant embodiment of the laser device;

[0042] Figure 6 is a second illustrative embodiment of a laser device according to the invention having a single interferometric optical amplification device in a free-space embodiment;

[0043] Figure 7 yes Figure 6 A simulation diagram of the behavior of the laser device;

[0044] Figure 8 shows a device with two cascaded interferometric optical magnifications Figure 6 A second embodiment of the laser device;

[0045] Figure 9 A third embodiment of a laser device according to the invention is shown, which has a single interferometric optical amplification device in a free-space embodiment; and

[0046] Figure 10 A plurality of cascaded interferometric optical amplification devices are shown. Figure 9 A third embodiment of the laser device. DETAILED DESCRIPTION

[0047] Figure 1 The basic aspects of a laser device according to the invention are shown schematically and are generally indicated at 10. It comprises an incident beam B i The amplifier system 12, the light beam B emitted from the amplifier system 12 o An optical return path 14, and a device 16 for outputting coherent optical radiation from the laser device, the optical return path 14 being adapted to return the light beam B o As the incident beam B iThe device 16 is coupled to the input of the amplifier system 12 and forms an optical resonant structure with the amplifier system 12, and is adapted to extract a portion of the beam emerging from the amplifier system (or, alternatively (indicated by the dashed line) a portion of the incident beam entering the amplifier system) and to provide said beam portion as output laser radiation B L emission.

[0048] As schematically represented in block 12, the amplifier system 12 comprises a single interferometric optical amplifying device 20 or a plurality of interferometric optical amplifying devices 20 connected in series or cascade. Each interferometric optical amplifying device 20 comprises an input beam splitting device adapted to spatially split an incident light beam into a first beam portion B1 and a second beam portion B2, wherein downstream of the input beam splitting device, the first beam portion B1 is directed into an amplifying arm 20a and the second beam portion B2 is directed into a non-amplified propagation arm 20b. A beam combining device, distinct from the input beam splitting device, is adapted to combine a first portion of the amplified light beam from the amplifying arm 20a of each interferometric optical amplifying device 20 and a second portion of the non-amplified propagation light beam from the propagation arm 20b of each interferometric optical amplifying device 20, thereby essentially forming a Mach-Zehnder interferometer, and the combining device of the last interferometric optical amplifying device in the series forms the light beam B emerging from the amplifier system 12. o .

[0049] The amplifying arm 20a comprises an active or gain region G capable of emitting photons coherent with the first portion of the optical beam Bl by stimulated emission following excitation obtained, for example, by means of optical or electrical pumping.

[0050] In a presently preferred embodiment, the active region comprises a semiconductor material to which is associated an electrical excitation system adapted to alter the thermodynamic equilibrium of a charge carrier population confined in the active region to determine inversion conditions and subsequent radiative recombination of the charge carrier population.

[0051] In alternative embodiments, the active region may include another material capable of supporting stimulated emission of photons following optical or electrical excitation.

[0052] Figure 2 A first schematic embodiment of a laser device according to the invention is shown, which has a single interferometric optical amplification device 20 in a free-space embodiment.

[0053] The interferometric optical amplifying device 20 includes: a device for converting the incident light beam B into iInput means BS for splitting the first beam portion B1 into the second beam portion B2, and output combining means BC for amplifying the first beam portion B1 in the active gain region G and the second beam portion B2. In a non-limiting example, the combined beam B1 emerging from the interferometric optical amplifying device 20 o At the input it returns to the same interferometric optical amplification device 20 via an optical return path 14 forming an optical resonant ring structure, comprising an optical reflector arrangement, four plane mirrors M1 - M4 .

[0054] In embodiments in which the active gain region G of the amplifying branch is formed by an optical semiconductor amplifier, it is advantageous to associate the input beam coupling stage 22 and the output beam collimation stage 24 with the active gain region G, which can alternatively be obtained by:

[0055] - a pair of aspheric lenses, a first lens adapted to focus the light beam entering the magnifying region and a second lens adapted to collimate the light beam leaving the magnifying region;

[0056] a pair of aspherical lenses and a pair of cylindrical lenses for circularizing the light beam, respectively a first lens adapted to focus and circularize the light beam entering the magnification zone and a second lens adapted to circularize and collimate the light beam leaving the magnification zone;

[0057] - a pair of spherical lenses and a pair of anamorphic prisms, entering and leaving the magnifying area respectively;

[0058] - an aspheric lens for focusing the light beam entering the magnification region; and a pair of cylindrical lenses for collimating and circularizing the light beam leaving the magnification region;

[0059] - a pair of micro lenses, for focusing and collimating the light beam entering and leaving the amplifying region, respectively;

[0060] a microlens for focusing the light beam entering the amplification region; and a pair of microlenses for collimating the light beam leaving the amplification region in the slow and fast axes.

[0061] The propagation arm 20b may include one or more reflective or refractive optical elements (not shown) for controlling the optical length of the propagation path and for controlling the spatial shape of the light beam, respectively.

[0062] The combining means BC at the output of the interferometric amplifying device 20 is formed by extracting the beam B emerging from the device 20. o A portion of the combined device is used as a loss beam, further forming a beam from the laser device (B L ) of the coherent light radiation output device 16.

[0063] Figure 3 Shown Figure 2A variant embodiment of the laser device, wherein the return optical path 14 includes four plane mirrors M1-M4 and two curved mirrors M5, M6 for folding and shaping the light beam.

[0064] The figure also shows an optical isolator 26 downstream of the active region G, which is adapted to allow the propagation of the first portion of the amplified light beam in a single predetermined direction. The isolator 26 may be present in any of the other embodiments described and may be arranged at any point in the resonant structure. However, since the gain device G emits in two directions, the isolator is advantageously arranged at the output of the active amplifying region for ease of alignment.

[0065] Figure 4 yes Figure 3 A simulation diagram of the behavior of the laser device, Figure 4 The output power is shown as a function of the spectral window relative to the origin of the graph. Specifically, the graph illustrates the results resulting from the interference between two beams (amplified and undisturbed). The fringes are due to the interference between the first beam portion B1, amplified in the active gain region G of arm 20a, and the second beam portion B2, propagating unamplified in arm 20b. The spacing between the fringes depends on the optical path. The dashed line represents the average power, while the dot-dash line represents the maximum power that can be extracted from the resonant structure of an interferometric device of the same size but without the propagation branches.

[0066] In the interference maximum, the device of the present invention shows better performance than a standard laser diode without an interferometric device. However, in the case of difficulties in balancing the interferometric device, i.e., in the case where it is impossible to make the optical paths in the two branches equal, the output power obtained is the average value shown in the graph.

[0067] Figure 5 The invention shows a method of amplifying a device having two cascaded interferometric optical magnification devices 20 and 20'. Figure 3 In a variant embodiment of a laser device, two cascaded interferometric optical amplification devices 20, 20' are connected via a beam splitter BS' that actuates the recombination of the light beams of the upstream interferometric amplification device 20 and the separation of the light beams of the downstream interferometric amplification device 20'. This variant embodiment makes it possible to employ interferometric amplification devices in which the difference in the optical lengths of the amplification and propagation arms 20a, 20b (respectively 20a', 20b') in each interferometric amplification device can be minimized or made equal.

[0068] Figure 6 FIG. 1 is a second exemplary embodiment of a laser device according to the invention, which has a single interferometric optical amplification device in a free-space embodiment. It shows a more compact structure, in which a beam splitting device BS and a beam combining device BC (different from the beam splitting device BS) are combined with an incident beam B.i The input path and output beam B o The output paths of the optical fiber 20a and the optical fiber 20b are substantially aligned, which is not conducive to the interference control between the first beam portion B1 amplified in the active gain region G of the arm 20a and the second beam portion B2 propagating without amplification in the arm 20b. The two arms 20a, 20b show a significant difference in optical length.

[0069] Figure 7 yes Figure 6 A simulation diagram of the behavior of the laser device, Figure 7 The output power is shown as a function of the spectral window relative to the origin of the graph. Specifically, the graph shows the results due to interference between two beams (amplified and undisturbed). The fringes are caused by the interference between the amplified and undisturbed beams. The spacing between the interference fringes between the first beam portion B1 amplified in the active gain region G of arm 20a and the second beam portion B2 propagating without amplification in arm 20b depends on the optical path, relative to Figure 4 The spacing between the fringes in the graph varies because the optical paths are different: narrower fringes correspond to larger differences in the optical paths taken by the beams. The dashed line represents the average power, while the dot-dash line represents the maximum power that can be extracted from the resonant structure of an interferometric device of the same size but without the propagating branches.

[0070] Figure 8 shows an interferometric optical amplification device with two cascaded Figure 6 The second embodiment of the laser device. Figure 5 configuration, which is more compact in a free space embodiment.

[0071] Figure 9 A third embodiment of a laser device according to the invention is shown, which has a single interferometric optical amplification device in a free-space embodiment.

[0072] Unlike the first and second embodiments, the means 16 for outputting coherent optical radiation from the laser device is arranged to extract a portion of the light beam conducted along the optical return path into the amplifier system and emit said beam portion as laser radiation at the output.

[0073] Figure 10 The invention shows a plurality of cascaded interferometric optical amplifying devices 20, 20', ..., 20 n of Figure 9 The first interferometric optical amplifying device is substantially similar to the interferometric optical amplifying device characterizing the above-described embodiments, except that the beam splitting device BS along the amplifying arm iThe first interferometric optical amplifying device is adapted to extract a smaller portion of the amplified light beam in order to direct it towards the amplifying arm of the subsequent downstream interferometric amplifying device, separated from the larger portion of the amplified light beam directed towards the combiner device BC. Thus, each intermediate interferometric optical amplifying device has an input beam splitter device BS i , the input beam splitter device BS i The combining device BC and the beam splitting device BS of each interferometric optical amplifier device only act on the beam of the amplifying arm 20a of the previous interference stage, but not on the recombined beam of the previous interference stage. i In contrast, the combining device BC collects the remaining beam portions B1' amplified in the active gain region G and passes them to the next stage, while the remaining beam portion B1' is not transmitted to the amplifying arm of the downstream device, and the beam portion B2 propagates without amplification. The combining device BC of each interferometric amplifying device can have a relatively depleted beam, which is advantageously directed toward a beam detector device D (e.g., a photodiode) suitable for monitoring the intensity and phase of the beam intermediate in the amplification chain.

[0074] The optical combined beam B emitted from a series of cascaded interferometric optical amplification devices in the amplification system o The optical return path 14 forms an optical ring resonator structure and returns to the input of the first interferometric optical amplifying device of the amplifying system.

[0075] The laser device according to the present invention offers various advantages over existing solutions. The described device demonstrates the advantages of coherent beam combining technology over currently used incoherent beam combining techniques. Compared to wavelength beam combining techniques, it allows for increased power while maintaining the spectral quality of the lasers. Compared to coherent beam combining architectures, it provides a powerful tool that avoids the need for active real-time phase control algorithms for each laser emitter, thereby facilitating manufacturing and industrial applications.

[0076] Furthermore, the implementation of a single resonant structure external to all amplifier stages offers the possibility to control the spatial shape of the optical beam directly in the cavity.

[0077] From a theoretical point of view, the only limit on the number of cascaded interferometric amplification devices is given by the gain saturation laws of the individual optical amplifiers of the amplification branches.

[0078] It should be noted that the embodiments proposed for the present invention in the above discussion are only non-limiting examples of the present invention. Those skilled in the art will be able to easily implement the present invention in different embodiments, but these different embodiments do not depart from the principles set forth herein and are therefore included in this patent.

[0079] This is particularly true with respect to the possibility of constructing beam splitting and combining devices, gain devices, and resonant structures according to techniques or configurations other than those described or mentioned above. For example, although an interferometric amplification device has been shown in which the amplifying arm is arranged along the transmission direction of an incident light beam on the beam splitting device and the non-amplifying propagation arm is arranged along the reflection or coupling direction of the incident light beam on the beam splitting device, the arrangement of the amplifying and propagation arms can be reversed relative to the beam splitting device, as long as the condition is observed that the majority of the optical power incident on the beam splitting device is directed towards the non-amplifying propagation branch.

[0080] Free space embodiments of devices with a large number of gain devices require particular attention to the optical alignment of the components, and more conveniently, the devices of the present invention can be achieved partially or entirely by guided optical devices, including fiber optic systems or systems with semiconductor integrated optical devices or other platforms (such as glass).

[0081] Naturally, without prejudice to the principle of the invention, the embodiments and implementation details may vary widely with respect to what has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of protection of the invention as defined by the appended claims.

Claims

1. A laser device (10) suitable for emitting coherent optical radiation, characterized in that The laser equipment comprises: A beam amplifier system (12) comprising a single interferometric optical amplifying device (20) or a plurality of interferometric optical amplifying devices (20, 20', ..., 20n) connected in series, wherein each interferometric optical amplifying device (20) comprises an input beam splitting device (BS) adapted to split an incident light beam (B i ) is spatially separated into a first beam portion (B1) and a second beam portion (B2), an amplifying arm (20a) of the first beam portion (B1) downstream of the input beam splitting device (BS) comprises an active gain region (G) capable of emitting photons coherent with the first beam portion, the amplifying arm (20a) and the propagating arm (20b) of the unamplified second beam portion (B2) extending to meet at the output of the interferometric optical amplifying device (20); beam combining means (BC), said beam combining means (BC) being different from said input beam splitting means (BS), said beam combining means (BC) being adapted to combine the amplified first beam portion (B1) and said second beam portion (B2) into a beam (B1) emerging from said amplifier system o ), the second light beam portion (B2) propagates without amplification in the single interferometric optical amplifying device (20) or the last interferometric optical amplifying device (20'; 20n) in the series; For the light beam (B) emitted from the beam amplifier system (12) o ), the return optical path (14) comprising an optical reflector device (M1-M6) adapted to reflect the outgoing light beam (B) at the input o ) is conducted to the beam amplifier system (12), thereby forming an optical ring resonance structure with the beam amplifier system (12); and A radiation output device (16) arranged to extract the light beam (B) emerging from the beam amplifier system (12) o ) and using the beam portion as radiation (B) of the laser device (10) L ) for transmission, The power of the first beam portion (B1) routed in the amplifying arm (20a) is less than the power of the second beam portion (B2) routed in the non-amplified propagating arm (20b).

2. The laser device (10) according to claim 1, wherein The amplifying arm (20a) comprises an active gain region (G) of semiconductor material capable of emitting photons coherent with the first beam portion (B1) after reaching a population inversion condition and subsequent radiative recombination of charge carriers confined in the active gain region (G), the active gain region (G) being associated with an electrical excitation system adapted to modify the thermodynamic equilibrium of the population of charge carriers in order to determine the population inversion condition.

3. The laser device (10) according to any one of the preceding claims, wherein In the interferometric optical amplifying device (20, 20'; 20, 20', ..., 20 n ), the input beam splitter (BS i ) is suitable for spatially separating the interfering first beam portion and second beam portion of the previous interferometric optical amplification device.

4. The laser device (10) according to any one of claims 1 or 2, wherein: In the interferometric optical amplifying device (20, 20'; 20, 20', ..., 20 n ), each intermediate interferometric optical amplifying device has an input beam splitting device (BS i ), the input beam splitter (BS i ) is only suitable for spatially splitting the first beam portion of the previous interferometric optical amplifying device, rather than the recombined beam of the previous interferometric optical amplifying device.

5. The laser device (10) according to any one of claims 1 or 2, wherein The light beam (B) emitted from the beam amplifier system (12) is transmitted as the output radiation (BL) of the laser device (10). o ) is a loss beam of the beam combiner (BC), the beam combiner (BC) being adapted to combine the amplified first beam portion (B1) and the second beam portion (B2) propagated without amplification into the beam (B1) emerging from the beam amplifier system (12). o ).

6. The laser device (10) according to claim 1, wherein As the output radiation (B L ) is transmitted from the beam amplifier system (12) to the beam (B o ) is a lost beam of one of the optical reflector devices (M1-M6) of the return optical path (14).

7. The laser device (10) according to any one of claims 1 or 2, wherein: The amplifying arm (20a) comprises an optical coupling and collimating device (22, 24) coupled to the active gain region (G), the optical coupling and collimating device (22, 24) comprising a pair of refractive systems, the pair of refractive systems being arranged to focus a first light beam portion (B1) entering the active gain region (G) and to collimate an amplified light beam portion leaving the active gain region (G), respectively.

8. The laser device (10) according to claim 1, wherein The non-amplified propagation arm (20b) comprises a reflective optical system or a dioptric system adapted to control the addressing or distribution of the lateral power of the second beam portion (B2).

9. The laser device (10) according to claim 1, wherein The optical reflector device (M1-M6) includes a plurality of total reflection reflective light systems.

10. The laser device (10) according to claim 1, wherein The light beam (B) emitted from the beam amplifier system (12) o ) includes: an optical element suitable for shaping the distribution of the lateral power of the light beam.

11. The laser device (10) according to any one of claims 1 or 2, wherein The laser device (10) further comprises an optical isolator (26) adapted to allow the light beam to propagate in a single predetermined direction.

12. The laser device (10) according to claim 1, wherein The optical length of the amplifying arm (20a) and the optical length of the non-amplified propagating arm (20b) of each interferometric optical amplifying device (20) are equal.

Images