Optoelectronic components, laser sources, optical amplifiers and optoelectronic circuits

Abstract

The invention relates to an optoelectronic component (1) suitable for integration into an optoelectronic circuit, the component (1) comprising: - a III-V semiconductor membrane comprising: • a P-doped layer (2) called P layer; • an intrinsic layer (3) deposited on the P layer (2); and • an N-doped layer called N layer deposited on the intrinsic layer (3); - an asymmetric photonic-crystal waveguide (6, 16, 26) called PhC waveguide formed in the membrane by a two-dimensional photonic crystal on one longitudinal side and by a total internal reflection face on the other longitudinal side; - electrical contacts (10, 11) arranged respectively on either side of the PhC waveguide (6, 16, 26) in the plane of the membrane, suitable for injecting charge carriers laterally relative to the membrane into the PhC waveguide (6, 16, 26); the layers (2, 3, 4) being arranged so that the intrinsic layer and the N layer (3, 4) only partially cover the P layer (2), forming a lateral face (5) extending perpendicularly from the surface of the P layer (2), part of the lateral face (5) forming the total internal reflection face of the PhC waveguide; the PhC waveguide (6, 16, 26) being arranged to be evanescently coupled to a passive semiconductor waveguide (12) in at least one coupling region.

Description

TECHNICAL FIELD

[0001] The present invention relates to an optoelectronic component suitable for integration into an optoelectronic circuit and to such an optoelectronic circuit.

[0002] The field of the invention is, without limitation, the field of optoelectronic components for information and communication technology. BACKGROUND

[0003] Optoelectronic components, such as laser sources, optical amplifiers, photodetectors or optical modulators, are generally made from bulk crystals of III-V semiconductors. Their typical length is about one millimeter, except for VCSEL (Vertical Cavity Surface Emitting Laser) type lasers. The electrical power required to drive these components is of the order of a few hundreds of mW. These characteristics limit the integration density of these components in an optoelectronic circuit.

[0004] Optoelectronic components integrated on silicon have been developed, in particular structures of the "ribbon" waveguide type, whose cross section is a few µm² (~ 10 µm²) and whose length is about 1 mm. Such components are described, for example, in the documents [1-3]. By design, these components only offer a reduced interaction of the light with the gain or active material of the waveguide, limiting their energy efficiency.

[0005] To reduce the size of these objects, the nanophotonic concept can be used, in which the light is confined in a volume of the order of the wavelength in the semiconductor material of the waveguide. However, the manufacturing of such optoelectronic components based on the nanophotonic concept is very complex.

[0006] Examples of such nanophotonic components are described in the documents [4] (laser), [5] (photodetector), [6] (modulator). The technology used is based on the production of a lateral p-i-n junction by implantation of dopants in the p and n layers. However, this technology is complex to implement, in particular requiring a unique epitaxy technology to confine the active material in the desired area. A high-temperature annealing procedure is also necessary to activate the implanted dopants. This has major drawbacks. First, the integration of these components into an optical circuit based on silicon photonics is very difficult. Indeed, due to the differences in the thermal expansion coefficients of the different materials involved during significant heating, in particular during annealing, the hetero-integration of these components in a silicon photonics circuit using a substrate transfer technology is very complex, even impossible. Second, this technology cannot be directly implemented on a microelectronic circuit, as the microelectronic circuit cannot be exposed to temperatures above 400°C.

[0007] The aim of the invention is to provide an optoelectronic component that makes it possible to overcome at least one of the described drawbacks.

[0008] [1] A. W. Fang et al, Opt. Express 16, 4413 (2008)

[0009] [2] H. Park et al, IEEE Photon. Technol. Lett. 19, 223032 (2007)

[0010] [3] H.-W. Chen et al, Opt. Express 16, 20571-76 (2008)

[0011] [4] S. Matsuo et al, Opt. Express 20, 3773-80 (2012)

[0012] [5] K. Nozaki et al, Optica 3(5), 483-492 (2016)

[0013] [6] K. Nozaki et al, APL Photonics, 2, 056105 (2017) SUMMARY

[0014] The subject of the application is to propose an optoelectronic component that can be densely integrated into a photonic circuit.

[0015] Another subject of the application is to propose an optoelectronic component with low energy consumption.

[0016] Another object of the application is to propose an optoelectronic component whose manufacture is compatible with CMOS technology (acronym for "Complementary Metal Oxide Semiconductor").

[0017] This object is achieved by an optoelectronic component suitable for being integrated into an optoelectronic circuit, the component comprising:

[0018] - a III-V semiconductor film comprising:

[0019] • a p-doped layer called p-layer,

[0020] • an intrinsic layer deposited on the p-layer, and

[0021] • an n-doped layer called n-layer deposited on the intrinsic layer;

[0022] - an asymmetric photonic crystal waveguide called PC waveguide formed in the film by a two-dimensional photonic crystal on one longitudinal side and by a total internal reflection face on the other longitudinal side;

[0023] - electrical contacts arranged in the plane of the membrane on one side and on the other side of the PC waveguide, respectively, adapted to inject charge carriers laterally with respect to the membrane into the PC waveguide;

[0024] the layers are arranged so that the intrinsic layer and the n layer only partially cover the p layer, forming a lateral surface extending perpendicularly from the surface of the p layer, a portion of the lateral surface forming a total internal reflection surface of the PC waveguide; and

[0025] the PC waveguide is arranged to evanescently couple to a passive semiconductor waveguide in at least one coupling region.

[0026] The optoelectronic element according to the application constitutes a basic element for designing specific optoelectronic elements that can be integrated into an optoelectronic circuit. The application thus proposes a unique design solution for an optoelectronic element having an active nano-photonic structure consisting of an asymmetric photonic crystal (PC) waveguide manufactured in a III-V semiconductor membrane. The active structure is coupled to a passive waveguide adapted to propagate optical information in a photonic circuit.

[0027] A portion of the lateral surface or rib represents a total internal reflection surface of the PC waveguide.

[0028] The electromagnetic field present in the element according to the application is strongly confined in the PC waveguide, which benefits from a lower energy consumption with respect to the prior art optoelectronic elements.

[0029] By arranging electrical contacts in the plane of the membrane on one side and on the other side of the PC waveguide and by the rib, the optoelectronic element according to the application allows for a lateral, rather than a vertical, injection of charge carriers. The injection into the membrane is thus effectively performed. The thickness of the membrane can thus be minimized (less than 500 nm) while avoiding the metal of the contacts to absorb the guided light in the PC waveguide. Such an element can reduce the footprint on a photonic circuit while still increasing the light confinement factor.

[0030] Due to their very compact structure, several of the optoelectronic elements according to the application can be densely integrated in a photonic circuit. The reduction of the element size thus makes it possible to increase the light-material interaction. Indeed, the confinement factor defined as the spatial overlap of the light intensity and the light emitting material generally increases from a few percent in the case of a strip waveguide configuration to more than 15% in the case of the application. This makes it possible to reduce the consumed electrical power. Moreover, the reduction of the size makes it possible to reduce the electrical capacity of the element, thus increasing its working frequency.

[0031] The optoelectronic element according to the invention particularly enables the co-integration of photonic and electronic circuits. Therefore, light can be used as an information carrier through electronic circuits, allowing at least partial replacement of metal interconnects via ultrafast photonic connections. Compared to prior art circuits, the energy efficiency and speed of this co-integrated element are greatly improved.

[0032] In the following text, the region between the total internal reflection surface and the PC in the intrinsic layer can be referred to as the "active region".

[0033] Its manufacturing process is compatible with CMOS technology used to manufacture electronic components and logic circuits. This is possible because only temperatures compatible with CMOS technology (<400°C) are used during the manufacturing process.

[0034] Advantageously, the p-contacts can be arranged on the p-layer opposite to the side, and the n-contacts can be disposed on the n-layer adjacent to the photonic crystal, such that the contacts are arranged parallel to the PC waveguide.

[0035] With this specific device, two electrical contacts are deposited on the same side of the optoelectronic element, on the other side relative to the passive waveguide to which it can be coupled, thereby facilitating the fabrication of the element.

[0036] This arrangement also allows for efficient injection of charge carriers. When a voltage is applied to the electrical contacts, electrons in the n-doped layer migrate through the PC region to reach the active region, while charge carriers from the p-contacts migrate towards the active region in the p-doped layer. The resistivity of the PC region is higher than that of the bulk material without PC. Therefore, charge carriers from the p-contacts have a shorter efficient path than electrons. By adjusting the volume through which charge carriers pass, the problem of unequal mobility between electrons and holes can be mitigated.

[0037] Alternatively, p-contacts can also be arranged below the p-layer. In this case, the p-contacts are located between the p-layer and the Si of the passive circuit.

[0038] According to one embodiment, the photonic crystal can be formed by holes extending through the n-layer, intrinsic layer, and p-layer, which form a two-dimensional periodic grating.

[0039] Advantageously, the PC waveguide may include a gain region.

[0040] As one example, the gain region may include quantum wells and / or quantum dots.

[0041] When light propagates in a PC waveguide and charge carriers are injected into the active region, the presence of quantum wells and / or points enables the localization of stimulated emission processes. The result is optical amplification.

[0042] According to one embodiment, the width of the PC waveguide can be gradually varied in at least one region coupled to the passive waveguide.

[0043] This allows for gradual adjustment of the effective refractive index of the guided modes in the PC waveguide, thereby reducing the difference in effective refractive index between the PC waveguide and the passive waveguide. The result is effective coupling without loss or reflection.

[0044] Advantageously, the corresponding distance of the electrical contact relative to the PC waveguide can be inversely proportional to the width of the PC waveguide.

[0045] Therefore, the resistance remains constant along the PC waveguide.

[0046] According to one embodiment, the PC waveguide may include a region having a slow light state (régime), wherein the photonic crystal includes local perturbations.

[0047] In fact, as the speed of light propagation in a PC waveguide slows down, the interaction time between the light and the material increases. The same amplification as a fast-state amplifier can then be obtained, but using an amplifier with a shorter group exponent factor than a fast-state amplifier.

[0048] According to one example, a PC waveguide may include two regions having a fast optical state, positioned upstream and downstream of a region having a slow optical state, respectively.

[0049] Regions with fast light states help to convert the guide light mode in a passive waveguide into a guide mode in regions with slow light states.

[0050] According to an advantageous embodiment of the optoelectronic element of the invention, a resonant optical cavity is formed in the PC waveguide by two mirror regions arranged in the propagation direction of the PC waveguide and by a region called the apodisation region.

[0051] Advantageously, at least one geometric parameter of the photonic crystal in the apodization region can be gradually varied in the propagation direction between the center and the end of the apodization region.

[0052] According to an embodiment, the element may also include an additional one-dimensional or two-dimensional photonic crystal adjacent to the side.

[0053] This additional photonic crystal can consist of one or two rows of additional holes arranged on one side of the PC waveguide. One of these additional rows can be specifically formed on a rib, thus the latter having a half-hole.

[0054] The addition of a photonic crystal enables a reduction in optical losses, in particular.

[0055] According to another aspect of the same invention, an optical amplifier is proposed, comprising an optoelectronic element according to the invention, the optical amplifier being configured to amplify light propagating in a PC waveguide when charge carriers are injected into the PC waveguide.

[0056] This nanoamplifier is an example of the production of non-resonant optoelectronic components.

[0057] Other specific optoelectronic components, particularly optical modulators or photodetectors, can be designed based on the non-resonant element according to the present invention. This design is achieved by adjusting the composition of the III-V semiconductor film.

[0058] According to another aspect of the invention, a laser source is provided, the laser source comprising an optoelectronic element, the optoelectronic element comprising a resonant cavity according to the invention, the resonant cavity comprising a gain region or an active material.

[0059] This laser source is an example of manufacturing resonant optoelectronic components.

[0060] Other specific optoelectronic components, particularly optical modulators or photodetectors, can be designed based on the resonant element according to the invention. This design is achieved by adjusting the composition of the III-V semiconductor film.

[0061] According to another aspect of the invention, an optoelectronic circuit is provided, comprising at least one of the following components according to the invention:

[0062] - Optoelectronic components,

[0063] -Amplifier, and

[0064] -Laser source.

[0065] Applications of this photonic circuit can be found in signal processing, remote communication, artificial intelligence, or sensor fields. Attached Figure Description

[0066] Further advantages and features will become apparent upon reviewing the detailed descriptions of the examples, which are by no means limiting, as illustrated in the accompanying drawings:

[0067] -[ Figure 1 ] Figure 1 Two views of a non-limiting embodiment of an optoelectronic element according to the present invention are shown;

[0068] -[ Figure 2 ] Figure 2 An example of a mode converter for an optoelectronic element according to one embodiment is illustrated schematically;

[0069] -[ Figure 3 ]Figure 3 As shown Figure 2 The spatial distribution of radiative recombination and optical guiding modes in the shown components is an example;

[0070] -[ Figure 4 ] Figure 4 An optoelectronic element according to an embodiment including a slow light guide is schematically illustrated;

[0071] -[ Figure 5 ] Figure 5 A detailed view of an embodiment of the resonant optical cavity according to the present invention is shown.

[0072] -[ Figure 6 ] Figure 6 It shows that in such Figure 5 An example of the longitudinal distribution of confined Gaussian modes in an optical cavity is shown;

[0073] -[ Figure 7 ] Figure 7 As shown Figure 5 An example of the spatial distribution of confined optical modes in the lateral direction within an optical cavity is shown.

[0074] -[ Figure 8 ] Figure 8 It shows that in such Figure 5 Examples of spatial distribution of resonant modes and radiative recombination in an optical cavity are shown; and

[0075] -[ Figure 9 ] Figure 9 The intrinsic quality factor of the resonant mode and the average density of injected carriers participating in the gain are shown as a function of the p-contact relative to, for example, Figure 5 The variation in the distance between the ribs of the PC waveguide in the optical cavity is shown. Detailed Implementation

[0076] It should be understood that the embodiments described below are by no means limiting. Variations of the invention can be particularly contemplated that include only a selection of the features described below (independent of the other features described), provided that the selection of features is sufficient to provide a technical advantage or to distinguish the invention from the prior art. This selection includes at least one preferred functional feature that has no structural detail or only a portion of the structural detail, provided that the portion of the structural detail alone is sufficient to provide a technical advantage or to distinguish the invention from the prior art.

[0077] In particular, all the variations and embodiments described can be combined together, provided there is no technical objection to such combination.

[0078] In a diagram, elements common to several diagrams can use the same reference numerals.

[0079] Figure 1Two schematic diagrams (perspective view (a) and cross-sectional view (b) respectively) of a non-limiting embodiment of an optoelectronic element according to the present invention are shown.

[0080] like Figure 1 As shown, the optoelectronic element 1 includes a semiconductor film, which includes a p-doped layer 2 called the p layer, an intrinsic layer 3 deposited on the p layer 2, and an n-doped layer 4 called the n layer deposited on the intrinsic layer 3.

[0081] like Figure 1 As shown in (b), layer 2 is not completely covered by intrinsic layer 3, but has an uncovered portion 2a. Intrinsic layer 3 is completely covered by n layer 4. Therefore, the edges 3a and 4a of layers 3 and 4 (intrinsic layer and n layer) (and optionally the edge 2a of a portion of p layer) form a side 5 extending vertically from the surface of p layer 2.

[0082] An asymmetric photonic crystal (PC) waveguide 6 is fabricated in optoelectronic component 1. For example... Figure 1 As shown, the PC consists of hexagonally arranged circular holes 7 etched in a film comprising a p-layer, an n-layer, and an intrinsic layer, thus forming a two-dimensional periodic grating. Light confinement in the asymmetric PC waveguide 6 is achieved on one longitudinal side by total internal reflection (TIR) ​​on the side 5, and on the other longitudinal side by the two-dimensional PC. Therefore, the PC waveguide 6 represents an asymmetric "rib" waveguide.

[0083] exist Figure 1 In (b), the horizontal arrow indicates the width of the PC waveguide.

[0084] The semiconductor film is made of III-V group materials. Depending on the operating wavelength of the device, the material can be based on GaN (visible range), GaS (near infrared), or InP (long-range communication range).

[0085] The operating wavelength of optoelectronic components is tuned by the geometry of the PC (diameter and period of the aperture) and the film (thickness), as well as the selection of III-V group materials.

[0086] Electrically, optoelectronic component 1 is a pin-type heterojunction (p-doped region - intrinsic region - n-doped region). The p and n electrical contacts are placed parallel to the PC waveguide 6. For example... Figure 1 As shown in the embodiment, p-contact 10 is arranged parallel to and facing side 5 on p-layer 2, and n-contact 11 is arranged parallel to the last row of holes 7 of PC on the side opposite to side 5. p-contacts and n-contacts 10, 11 are arranged adjacent to PC waveguide 6. For example, the distance between the rib and the p-contact can be <1µm, and the n-contact can be arranged at a distance of approximately 2µm to 4µm from the center of PC waveguide 6.

[0087] Energizing the electrical contacts 10 and 11 allows charge carriers to be injected into the region of the PC waveguide 6.

[0088] Optoelectronic component 1 is coupled to passive waveguide 12. In the illustrated embodiment, component 1 is arranged above passive waveguide 12 such that PC waveguide 6 and passive waveguide 12 are evanescently coupled in at least one coupling region. Passive waveguide 12 is made of silicon-based material (Si, SiN, SiO2, SiON, etc.). It can form part of a passive circuit and allow the propagation of optical information.

[0089] The arrangement of electrical contacts 10 and 11 parallel to PC waveguide 6 in the plane of the membrane allows for the lateral injection of charge carriers. This makes it particularly possible to minimize the membrane thickness, thereby reducing the size of the component and increasing the confinement factor.

[0090] The asymmetric arrangement of the PC waveguide and p- and n-contacts takes into account the large difference in mobility between electrons and holes. For electrons, the mobility is 80 times greater. Radiative recombination of charge carriers is firmly positioned within the PC waveguide 6. In fact, the p-contacts are fabricated as close as possible to the side 5 of the PC waveguide 6, while the n-contacts are fabricated on the opposite side of the PC aperture 7. Because the resistivity of the film with PC is greater than that without PC, holes take a much shorter path to reach the PC waveguide 6 than electrons, thus achieving excellent spatial overlap between the optical guide mode and radiative recombination.

[0091] like Figure 1 The optoelectronic element 1 shown can be used to obtain resonant or non-resonant optoelectronic elements.

[0092] Examples of non-resonant and resonant elements will be described below.

[0093] An example of a non-resonant optoelectronic device according to an embodiment of the present invention is an optical nanoamplifier. In order to enable the PC waveguide to be used as an amplifier, it must include a gain region. This gain region can be obtained, for example, by introducing multiple quantum wells or quantum dots.

[0094] Nanoamplifier has the same characteristics as reference Figure 1 The technical characteristics are similar to those of the described optoelectronic components.

[0095] The amplifier also includes several quantum wells or quantum dots inserted into the III-V film at the PC level to create parasite defects therein. In this active material, light amplification is generated through a stimulated emission process. As the optical signal propagates in the PC waveguide and charge carriers are simultaneously injected into the PC waveguide region, the optical amplification of the signal is produced by the radiative recombination of the charge carriers. For this purpose, the wavelength of the optical signal and the wavelength of the radiation emitted during the recombination process must be the same. This wavelength is called the operating wavelength.

[0096] The geometry of the PC can be selected to obtain a single-mode waveguide at the operating wavelength. The geometry can also be adjusted to change the effective refractive index, confinement factor, and gain of the guided mode.

[0097] According to one embodiment, the PC waveguide is coupled to a passive waveguide (located in...) via an evanescent wave. Figure 1 (below in (a)). To generate this ephemeral coupling, a linear or adiabatic coupler can be used. The coupler gradually converts the confined optical mode in the passive waveguide to the confined optical mode in the PC waveguide. To do this, the difference in effective refractive index between the two waveguides is gradually changed according to the propagation distance of the mode. Therefore, the difference in effective refractive index in the coupling region is reduced.

[0098] Figure 2 (Above, (a)) This diagram illustrates an example arrangement of the linear coupler 100 or mode converter (conical). The effective refractive index of the guided mode in the PC waveguide 16 is adjusted by gradually varying the width of the PC waveguide 16. The width of the passive waveguide 12 remains constant. Due to the variation in the width of the PC waveguide 16 in the region of the coupler 100, its effective refractive index is gradually adapted.

[0099] The optical power transmission from passive waveguide 12 to PC waveguide 16 thus obtained is as follows: Figure 2 As shown in Figure (b) below. Figure 2 (b) shows the simulation results of converting guided mode 22 in passive waveguide 12 to guided mode 29 in PC waveguide 16. The spatial distribution of electromagnetic fields in the individual guides in the lateral direction at the input (e) and output (s) of coupler 100 and in the longitudinal direction (l) along the entire length of coupler 100 is shown.

[0100] To achieve optical amplification, the intensity distribution of the electromagnetic field propagating in the PC waveguide, the intensity distribution of radiative recombination, and the overlap between the active materials (quantum wells and / or points) were optimized. This necessitates optimizing the design of the PC waveguide to maximize the concentration of injected charge carriers that induce stimulated emission events.

[0101] Figure 3 It shows according to Figure 2 The spatial distribution of the radiative recombination rate (curve 41) in the PC waveguide 16 of the component in the embodiment is superimposed with the spatial distribution of the optical guide mode (curve 42).

[0102] According to one embodiment, the nanoamplifier may include a region having a slow-light state. For this purpose, the geometry of the PC is selected such that guided modes with slow group velocities are available at the desired wavelength.

[0103] As an example, local perturbations can be applied to the aperture array closest to the component ribs in the PC. These local perturbations can consist of a diameter slightly different from the other apertures or a different relative position of the grating with respect to the apertures. For example, the aperture period can vary between approximately 1% and 30%. The effect of this is to reduce group velocity dispersion in the PC waveguide, thereby expanding the operating wavelength band of the amplifier in slow light conditions.

[0104] To couple the guided mode into the passive waveguide within the PC waveguide at slow speeds, a mode conversion process involving several steps is necessary. The following will refer to... Figure 4 Examples describing a series of mode transitions.

[0105] Linear or adiabatic converter 31, as referenced Figure 2 The guided mode in the silicon-based passive waveguide can be converted to the fundamental mode of the PC waveguide, represented by a converter. The fundamental mode of the PC waveguide is then coupled to the fundamental mode of the ridge waveguide 32, where light guidance is achieved solely through total internal reflection. An additional structure 33 couples the mode of the ridge waveguide to the slow mode of the PC waveguide 34. The additional structure 33 consists of a PC waveguide, where the period of the PC varies linearly in the direction of light propagation. The ridge waveguide 32 allows the fundamental guided mode of the PC waveguide to be transferred to the slow light band of the PC waveguide 34.

[0106] The converter is arranged in the opposite manner at the output of the slow-light PC waveguide 34.

[0107] For example, for a non-resonant optoelectronic component operating as an optical amplifier at a wavelength λ of 1550 nm, the period of the aperture in the PC is approximately 260 nm, the aperture radius is approximately 100 nm, the film thickness is approximately 450 nm, and the thickness of the passive waveguide circuit is approximately 220 nm. The film thickness is given by λ / n, where n is the refractive index of the film (3, 34).

[0108] An example of a resonant optoelectronic element according to an embodiment of the present invention will be described below. The resonant optoelectronic element has the same characteristics as the reference... Figure 1 The technical characteristics are similar to those of the described optoelectronic components.

[0109] Resonant optoelectronic components also include resonant optical cavities. Figure 5 A detailed view of an embodiment of this resonant optical cavity is shown.

[0110] like Figure 5 As shown, the optical cavity 20 is formed in the PC waveguide 26 by two mirror regions 27a and 27b and a region called the apodization region 28, with the mirror regions arranged along the propagation direction of the PC waveguide 26. The mirror regions and the apodization region are generated in the PC. Figure 5 The side 5 and p-contact 10 of the PC waveguide 26 are also shown.

[0111] The optical cavity 20 may also include regions with active material, possibly having quantum wells and / or points, as described above for nanoamplifiers.

[0112] To generate the reflector regions 27a, 27b and the apodization region 28a, the geometric parameters of the PC are changed and adjusted, such as the period or radius of the hole 7, the width of the guide, etc.

[0113] In the mirror regions 27a and 27b, by preventing light from propagating beyond the mirror regions 27a and 27b respectively, the photonic bandgap located below the slow group velocity mode in frequency is used to confine the mode between the mirrors.

[0114] In the apodization region 28, one or more geometric parameters of the PC, such as the width of the guide, the period of the aperture, or the diameter, gradually change from the end of the cavity toward the center in the propagation direction. In particular, a resonant mode with a Gaussian space shape can be obtained in this way.

[0115] Typically, due to the asymmetry of PC waveguides, in addition to the dominant transverse electric (TE) polarization amplitude, there exists a non-negligible transverse magnetic (TM) polarization amplitude in the confined electromagnetic field during resonant modes. The TM polarization amplitude is not reflected by the mirrors and is therefore not confined within the cavity, resulting in significant optical losses and preventing the attainment of a high quality factor.

[0116] To avoid or reduce these losses, the cavity can include one or two rows of additional holes on one side of the rib or side of the PC waveguide. (Relative to...) Figure 1 According to the embodiments in the example, Figure 5 The cavity 20 of the illustrated embodiment also includes two rows of additional holes 17 for the element. One of these rows is formed across the rib 5, leaving a half-hole in the side, while the other row is formed in the p layer near the rib 5.

[0117] Therefore, as Figure 5 The resonant optoelectronic device described above can achieve a high quality factor (Q>10). 5 The cavity 20. An example of the longitudinal distribution 43 of the restricted Gaussian mode in cavity 20 is shown below. Figure 6 As shown. Figure 7 An example of the spatial distribution of optical modes in the transverse direction in cavity 20 is shown. Figure 8 The superposition of the spatial distribution of optical modes (curve 51) and radiative recombination (curve 52) in cavity 20 is shown.

[0118] Such resonant cavities, which contain regions of active material, can be used in particular for fabricating nanolaser diodes.

[0119] For example, for a resonant optoelectronic component operating as a laser source at a wavelength λ of 1550 nm, the period of the hole in a PC is approximately 333 nm, the radius of the hole is approximately 75 nm, and the film thickness is approximately 450 nm. The thickness of a silicon-based passive circuit is approximately 220 nm.

[0120] For electrical injection into this type of cavity, the following limitations must be considered:

[0121] •like Figure 7 As shown, the optical mode therefore extends slightly in the lateral direction within the aperture region of the PC. This reduces the spatial overlap between the optical mode and the gain distribution (see...). Figure 8 Then the net gain obtained can be reduced.

[0122] • The additional holes can increase the resistivity of the p-layer.

[0123] However, sufficient levels of electrical injection can be achieved, and thus laser emission (lase) of the structure can be induced by adjusting the distance between the metal electrical contacts of the p-layer and the ribs of the PC guide.

[0124] The distance between the electrical contacts of a PC waveguide can be inversely proportional to the width of the PC waveguide.

[0125] Figure 9 The intrinsic quality factor Q (curve 53) of the resonant mode and the average density of injected carriers participating in the gain (curve 54) are shown as a function of the distance between the p-contact and the rib of the PC waveguide. The result is that as the distance increases, the optical losses associated with absorption by the metallic contact decrease, i.e., the quality factor Q increases, but the injection efficiency also decreases. It is then necessary to find a trade-off, for example, by modeling the laser based on these constraints.

[0126] The optoelectronic element according to the above embodiment is a hybrid structure that can be manufactured according to the following known techniques.

[0127] A semiconductor III-V heterostructure is attached to a silicon (Si)-based waveguide circuit. Techniques for achieving this attachment can include bonding, wafer fusion, and direct substrate attachment via thermopressing. A dielectric layer (typically SiO2) is pre-inserted between the semiconductor III-V heterostructure and the Si-based waveguide circuit to modulate the evanescent coupling power to a desired value. Typically, the thickness of this modulating layer varies between 50 nm and 500 nm.

[0128] After attachment, a semiconductor film is constructed using two levels of photolithography and subsequent plasma-assisted etching to produce PC and ribs.

[0129] Metal contacts located on the p-layer and n-layer are defined using photolithography. The deposited metal is selected based on the material type and the doping of the layers used. Annealing of these contacts may be necessary to obtain ohmic contacts. The annealing temperature must not exceed 400°C to maintain compatibility with CMOS technology.

[0130] These structures are then encapsulated in a low-refractive-index dielectric material.

[0131] Finally, electrical connectors (through holes) are made and metallized over the metal contacts to enable power supply to the optoelectronic components.

[0132] Of course, the present invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the present invention.

Claims

1. An optoelectronic element (1) suitable for integration into an optoelectronic circuit, the element (1) comprising: - III-V semiconductor films, including: • The p-doped layer, referred to as the p-layer (2). • The intrinsic layer (3) deposited on the p layer (2), and • An n-doped layer (4) called the n-layer is deposited on the intrinsic layer (3); - An asymmetric photonic crystal waveguide (6, 16, 26), referred to as a PC waveguide, is formed in the film via a two-dimensional photonic crystal on one longitudinal side and via a total internal reflection surface on the other longitudinal side; - Electrical contacts (10, 11) are respectively arranged on one side and the other side of the PC waveguide (6, 16, 26) in the plane of the membrane, and are adapted to inject charge carriers into the PC waveguide (6, 16, 26) laterally relative to the membrane. The intrinsic layer (3) and the n layer (4) only partially cover the p layer (2), forming a side surface (5) that extends vertically from the surface of the p layer (2), and a portion of the side surface (5) forms the total internal reflection surface of the PC waveguide; The PC waveguides (6, 16, 26) are arranged to be transiently coupled to the passive semiconductor waveguide (12) in at least one coupling region.

2. The element (1) according to claim 1, characterized in that, The p-contact (10) of the electrical contacts (10, 11) is arranged on the p-layer (2) facing the side (5), and the n-contact (11) of the electrical contacts (10, 11) is arranged on the n-layer (4) adjacent to the two-dimensional photonic crystal, such that the electrical contacts (10, 11) are arranged parallel to the PC waveguide (6, 16, 26).

3. The element (1) according to claim 1 or 2, characterized in that, The two-dimensional photonic crystal is formed by holes (7) extending through the n-layer (4), the intrinsic layer (3) and the p-layer (2), and the holes (7) form a two-dimensional periodic grating.

4. The element (1) according to claim 1 or 2, characterized in that, The PC waveguides (6, 16, 26) include a gain region.

5. The element (1) according to claim 4, characterized in that, The gain region includes quantum wells and / or quantum dots.

6. The element (1) according to claim 4, characterized in that, The width of the PC waveguides (6, 16, 26) gradually varies in at least one region coupled to the passive semiconductor waveguide (12).

7. The element (1) according to claim 6, characterized in that, The corresponding distances of the electrical contacts (10, 11) relative to the PC waveguides (6, 16, 26) are inversely proportional to the width of the PC waveguides (6, 16, 26).

8. The element (1) according to claim 4, characterized in that, The PC waveguides (6, 16, 26) include a region (34) with a slow light state, wherein the two-dimensional photonic crystal includes local perturbations.

9. The element (1) according to claim 8, characterized in that, The PC waveguide (6, 16, 26) includes two regions (33) with fast light state, which are respectively arranged upstream and downstream of the region (34) with slow light state.

10. The element (1) according to claim 1 or 2, wherein, A resonant optical cavity (20) is formed in the PC waveguides (6, 16, 26) by two mirror regions (27a, 27b) arranged in the propagation direction of the PC waveguides (6, 16, 26) and by a region called the apodization region (28).

11. The element (1) according to claim 10, characterized in that, At least one geometric parameter of the photonic crystal in the apodization region (28) gradually changes in the propagation direction between the center and the end of the apodization region (28).

12. The element (1) according to claim 10, characterized in that, The element includes an additional one-dimensional or two-dimensional photonic crystal (17) adjacent to the side.

13. An optical amplifier comprising an optoelectronic element (1) according to any one of claims 4 to 9, the optical amplifier being configured to amplify light propagating in the PC waveguide when charge carriers are injected into the PC waveguide (6, 16, 26).

14. A laser source comprising an optoelectronic element (1) according to claim 4 or 5 in conjunction with any one of claims 10 to 12.

15. An optoelectronic circuit comprising at least one of the following: - The optoelectronic element (1) according to any one of claims 1 to 12. - The amplifier according to claim 13, and - The laser source according to claim 14.

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