Photonic device comprising a glass substrate and an optical pattern arranged on the substrate

Abstract

The invention relates to a photonic device (1) comprising a glass substrate (S) incorporating an optical waveguide array. This array comprises at least one waveguide (Gc, Gi) which is able to propagate an optical mode and has a first portion flush with a face (Sa) of the substrate (S). The photonic device (1) also comprises a first layer, made of a material which is able to propagate radiation from the optical mode, arranged on the first face (Sa) of the substrate (S). The first layer at least partially covers the first portion of the waveguide. The first layer defines an optical pattern (M) which is configured to be optically coupled to the waveguide (Gc, Gi). Figure 1

Description

A photonic device comprising a glass substrate and an optical pattern placed on the substrate. FIELD OF INVENTION

[0001] The present invention relates to a photonic device and falls within the field of integrated photonics. Integrated photonics is a field of photonics that focuses on integrating multiple optical functions onto a single chip, in a manner analogous to how electronic integrated circuits integrate electronic components. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] The document by Broquin et al "Integrated Photonics on Glass: A Review of the Ion-Exchange Technology Achievements" AppliedSciences 11, no. 10: 4472 reminds us that integrated photonics does not rely on a single technology platform and that silicon photonics, III-V photonics, polymer photonics, LiNbO3 photonics and glass photonics coexist in parallel, each of them presenting its own disadvantages and advantages.

[0003] Using a glass-based technology platform for photonic devices offers numerous advantages, primarily due to the inherent properties of this material. A glass substrate exhibits exceptional transparency across a broad spectrum of wavelengths, encompassing both visible and infrared regions, which is essential for a wide range of optical applications. This low optical loss ensures minimal attenuation of the optical signal, thus preserving its integrity as it propagates through the device.

[0004] In addition to optical advantages, a glass substrate offers significant thermal and mechanical benefits. Its low coefficient of thermal expansion ensures dimensional stability, even under varying temperature conditions, thus preserving device performance and reliability. The mechanical strength of glass substrates provides robust support for delicate photonic structures, protecting them from potential damage. Furthermore, glass can be easily fabricated and shaped using standard microfabrication techniques.

[0005] Another notable advantage of a glass-based technology platform is its compatibility with various photonic materials and processes, facilitating the integration of diverse photonic components such as waveguides, modulators, and detectors. In particular, the compatibility of glass with optical fibers, often made from similar materials, enables efficient coupling and reduces insertion losses.

[0006] These numerous advantages make glass an ideal material for the development of advanced photonic devices and integrated photonic circuits.

[0007] US2004 / 057690 proposes forming a partially embedded waveguide within a glass substrate. The embedded portion exposes the edge of the glass substrate, facilitating coupling with an optical fiber. The unembedded portion of the waveguide guides the optical mode along large radii of curvature on the surface of the glass substrate. The substrate is coated with a mode-confining coating, and only an evanescent portion of the mode propagates through the coating. Therefore, in this design, the optical mode propagates only within the waveguide formed in the glass substrate, thus limiting the functionalities that can be implemented. SUBJECT OF THE INVENTION

[0008] One aim of the invention is to provide a photonic device that takes advantage of the listed benefits of a glass platform, without, however, exhibiting the limitations of the prior art document. BRIEF DESCRIPTION OF THE INVENTION

[0009] To achieve this goal, the object of the invention proposes a photonic device comprising: a glass substrate having a first face, a second face opposite the first face, a slice connecting the first face to the second face and incorporating an array of optical guides comprising at least one waveguide capable of propagating an optical mode, the waveguide having a first portion flush with the first face of the substrate; a first layer formed of a material capable of propagating light radiation from the optical mode, disposed on the first face of the substrate and covering at least part of the first portion of the waveguide, the first layer defining, on this first face, an optical pattern configured to be optically coupled to the waveguide so that the optical mode propagating in the waveguide is transferred into the optical pattern.

[0010] According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination: at least one waveguide comprises a coupling waveguide having a second portion intersecting the slice of the substrate, the coupling waveguide being partly buried in a thickness of the substrate; at least one waveguide comprises an internal waveguide having a first portion and a second portion both flush with the first face; the internal waveguide comprises an intermediate portion buried in the substrate, the intermediate portion being disposed between the first portion and the second portion; the first layer is formed of a material selected from the list consisting of silicon nitride, lithium niobate, silicon, aluminum oxide, indium phosphide;The photonic device further comprises a protective cover formed of a polymer layer disposed on at least a part of the first face and, advantageously, completely encapsulating the optical pattern; the photonic device further comprises a protective cover having an assembly face, the protective cover being assembled to the first face of the substrate by its assembly face, the assembly face being provided with at least one recess to house the optical pattern; the protective cover is made of the same material as that constituting the substrate or of a material having the same coefficient of thermal expansion; the photonic device further comprises an adhesive layer between the assembly face of the protective cover and the first face of the substrate; the protective cover comprises at least one complementary waveguide, the at least one complementary waveguide combining with the second portion of the at least one waveguide;The mounting face of the protective cover does not extend over the entire first face of the substrate, and leaves an exposed area of ​​this first face; the protective cover is transparent and includes at least one optical element such as a lens; the optical pattern has a tapered or segmented shape that at least partially overhangs the first portion of the coupling waveguide; the optical pattern includes a banded or ribbed waveguide; the optical pattern implements an optical function, such as a filter; the optical pattern is formed of at least two non-contiguous parts and the optical guide array also includes an internal waveguide optically coupling the two non-contiguous parts; the optical guide array also includes an internal waveguide that is completely overhung by the optical pattern; the substrate has a U-shaped or V-shaped groove at the edge intersecting the second portion of the waveguide to receive the end of an optical fiber;The optical pattern extends to an edge of the first face; the optical guide array comprises a plurality of coupling waveguides, some of which are arranged on one side of the substrate and others on the opposite side of the substrate.

[0011] According to another aspect, the invention proposes a photonic system comprising an optical device as above described, and at least one optical fiber placed against the edge of the substrate opposite the second portion of the coupling waveguide.

[0012] Other features and advantages of the invention will become apparent from the detailed description of the invention which follows with reference to the accompanying figures in which:

[0013]

[0014] Laillustre a photonic device conforming to the invention;

[0015]

[0016] Lare represents a substrate of a photonic device incorporating an array of optical guides in top view and according to section AA;

[0017]

[0018] La represents the substrate according to section BB of this figure;

[0019]

[0020] Laillustre two approaches to coupling an optical fiber to a photonic device according to the invention;

[0021]

[0022] Laillustre un mode de propagation d’une rayon lumière dans un motif optique de un dispositif conforme à l’invention;

[0023]

[0024]

[0025]

[0026]

[0027] Figures 5a, 5b, 5c, 5d represent photonic devices according to the invention and implementing a variety of optical functions;

[0028]

[0029] Laillustre an implementation method in which a protective cover for a photonic device according to the invention presents a complementary waveguide;

[0030]

[0031]

[0032] Figures 7 and 8 illustrate other characteristics of a photonic device according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] Larepresents, by way of illustration, a photonic device 1 conforming to the invention.

[0034] This photonic device 1 first comprises a glass substrate S. This substrate is delimited by a first face Sa, a second face Sb opposite the first face Sa, and a slice Sc peripherally connecting the first face Sa to the second face Sb.

[0035] Without this constituting a limitation and for illustrative purposes only, the substrate thickness can range from 500 microns to 1 mm. It can extend in a plane and take a rectangular shape in that plane, and extend over a surface area typically ranging from a few mm² to a few cm².

[0036] The exact nature of the glass from which substrate S is formed can be arbitrary, provided that this substrate can be treated by ion exchange to incorporate, as will be described later, an array of optical guides. In general, the glasses from which substrate S can be made are suitable for ion exchange, typically involving the replacement of smaller ions (e.g., sodium) with larger ions (e.g., potassium, silver, or thallium) from a bath, such as a molten salt bath. This ion exchange allows the refractive index profile to be locally modified to suit light guiding.

[0037] It can be an alkali-silicate glass, and in particular a borosilicate glass. The glass can be doped with other elements such as Erbium for light-amplification properties, for example.

[0038] As shown in Figure 1, the substrate S incorporates an array of optical waveguides. This array is designed to propagate one or more optical modes within the photonic device 1. In this illustration, the optical waveguide array is formed by a plurality of waveguides, each waveguide being defined within the thickness of the substrate as a volume with a refractive index different from the rest of the substrate. This refractive index allows light radiation to propagate within the substrate S according to the optical modes guided by the array.

[0039] The cross-section of a waveguide typically has a circular or ellipsoidal shape when embedded in the substrate, or a portion of a circle or ellipse when it is flush with the substrate's surface. The dimensions of this cross-section, at its widest point, can be on the order of a micrometer or a few micrometers. The guided mode, at a wavelength of 1550 nm, can have a cross-section on the order of 10 micrometers.

[0040] In the optical guide network, we distinguish between so-called "coupling" waveguides Gc, whose volume of different refractive index intersects the Sc slice of the substrate S, and so-called "internal" waveguides Gi, whose volume of different refractive index does not intersect the Sc slice of the substrate S.

[0041] A coupling waveguide Gc is specifically designed to propagate light radiation to or from the environment outside the device. For this purpose, an optical fiber (or more generally, a photonic component) of a surrounding photonic system can be placed against the edge Sc of the substrate S, opposite the portion of the coupling waveguide Gc that intersects the edge, in a butt-coupling configuration. This assembly can be facilitated by placing a component on the first face Sa of the substrate that acts as a mechanical stop for the fiber end, thus facilitating precise positioning and adhesion of the fiber, particularly when the coupling waveguide is flush with the first face Sa of the substrate S.Alternatively, a U-shaped or V-shaped groove can be formed on the edge of the substrate, at the portion of the coupling waveguide Gc that intersects the edge, this groove allowing the fiber to be precisely positioned so that its core is aligned with the coupling waveguide.

[0042] It should be noted that the coupling of an optical fiber to a glass substrate S can be achieved particularly efficiently, limiting optical coupling losses, since the fiber and substrate are made of similar materials. This coupling efficiency constitutes a significant advantage of a photonic device according to the invention.

[0043] However, the photonic device 1 does not require optical fiber to operate, as the light radiation can propagate in the photonic system in which the device takes place by simple propagation in free space.

[0044] Each waveguide Gc,Gi of the optical waveguide array includes at least one portion that is flush with the first face Sa of the substrate S. This flush portion allows the waveguide to be optically coupled to a first layer located on and above the first face of the substrate S, as will be detailed later. The cross-section of the waveguide at its flush portion has a general elliptical shape, as shown in the figure.

[0045] Some waveguides in the optical waveguide array may consist entirely of a flush portion. Other waveguides may also have a buried portion, meaning that the volume with a different refractive index in this portion is entirely embedded within the substrate S and is located at a specific distance from the first face Sa of this substrate. As previously shown, the cross-section of a waveguide at its buried portion generally has an elliptical, or possibly circular, shape, as illustrated in Figure 1. Burying a portion of the waveguide is beneficial for preserving the quality of an optical mode that may propagate through it. This prevents the optical mode from interacting with elements that might be present on the first face Sa of the substrate S during its propagation.

[0046] We have thus represented a coupling waveguide Gc1 consisting of a first exposed portion and a second buried portion, this second portion intersecting the Sc layer of the substrate. We have also represented another coupling waveguide Gc2 and an internal waveguide Gi2 consisting of a single exposed portion. An internal waveguide Gi, when it has a buried portion, generally has two exposed portions, arranged on either side of the buried portion.

[0047] The optical guide array incorporated into the substrate S can mix any type of waveguide, coupling and internal, with or without a buried portion, according to any arrangement suitable for the intended application. In any case, an optical guide array compatible with a photonic device 1 according to the invention comprises at least one waveguide Gc,Gi formed of a portion flush with the first face Sa.

[0048] To fabricate the substrate S equipped with its array of optical waveguides, a well-known ion exchange technique can be used, described, for example, in detail in the technical document provided in the introduction to this application. In general terms, a glass substrate without any waveguides can be fitted with a mask on its first face. This mask has open areas defining the location of the waveguides forming the array. The ion exchange operation is then carried out at the open areas, for example, by immersing the substrate in a molten salt bath. This operation generally involves replacing smaller ions (for example, sodium) in a surface region of the substrate at the open areas of the mask with larger ions (for example, potassium, silver, or thallium) from the bath. This ion exchange can be assisted by an electric field.This leads to the definition of surface regions in the volume of the substrate S exhibiting a refractive index different from the rest of the substrate S.

[0049] To bury part of these surface regions and thus form the buried portions of the waveguides, a second ion exchange step is carried out, with sodium ions for example, by applying an electric field to the substrate whose profile, in the plane, locally defines the burial depth of the portions.

[0050] Other methods for fabricating the waveguide array are of course possible for forming at least some of the waveguides that compose it. These waveguides, particularly when they reside on the surface of the first face Sa of the substrate S, can thus be formed by laser treatment of this face.

[0051] Continuing the description of the photonic device 1 illustrated in Figure 1, this device comprises a first layer disposed on and in contact with the first face Sa of the substrate S. The first layer covers at least part of the flush portion of the waveguide. More generally, the first layer covers at least part of the flush portions of at least some of the waveguides forming the optical guide array. The first layer defines, on the first face Sa of the substrate S, an optical pattern M configured to be optically coupled to the optical guide array, meaning that an optical mode propagating in the optical guide array is also capable of propagating in the optical pattern M.

[0052] The first layer is therefore made of a material capable of propagating light radiation from the optical mode propagating in at least one waveguide of the substrate S. For example, this first layer can be made of silicon nitride, lithium niobate, silicon, aluminum oxide, or indium phosphide. The first layer can be deposited on the first face Sa of the substrate S using any suitable deposition technique. Alternatively, it can be transferred, using a layer transfer technique, onto the first face Sa of the substrate S, which notably allows for the creation of an optical pattern M made of a crystalline material.

[0053] It is not necessary for this first layer to be composed of a single material and, in general, the optical pattern can employ a plurality of materials, successively or simultaneously formed on the first face of the substrate S.

[0054] Nor is it necessary for the first layer to extend continuously across the first face of the substrate S. The optical pattern M formed by this first layer can thus be composed of non-contiguous parts separated from each other by gaps in the substrate S that are devoid of any layer. An internal waveguide Gci can be provided to optically couple the two non-contiguous parts of a pattern.

[0055] In all cases, the term "first layer" refers to the thickness of material(s) formed on and in contact with the first face Sa of the support S, and within which an optical mode of the optical guide array is also able to propagate. This thickness is not necessarily uniform throughout its extent, and the first layer may be structured to exhibit areas of distinct thicknesses.

[0056] The optical pattern M is therefore configured to guide an optical mode to or from the optical guide array of the support. For this purpose, the optical pattern M advantageously has a tapered or segmented shape Ze, overhanging at least part of the flush portions of the waveguides of the optical guide array.

[0057] We have thus represented in Figure 1 a possible implementation of the optical pattern M incorporating such tapered shapes Ze. In Figure 1, and as can be seen in the cross-section of this figure, an optical mode propagates entirely guided and confined within the optical pattern M, that is, within the thickness of the first layer. This optical pattern M can therefore include a band waveguide (left cross-section in Figure 1) or a ribbed waveguide (right cross-section in Figure 2).

[0058] It is noted that it is possible to configure the optical pattern M, in particular by defining the width (the dimension transverse to the propagation direction of the optical mode) to confine the light radiation. Such confinement is advantageous because it allows for more precise guidance of the light radiation, and in particular makes it possible to create an optical pattern M with a very small radius of curvature, for example on the order of 100 micrometers or less, and in all cases much smaller than the radius of curvature of the waveguides incorporated into the substrate S.

[0059] Advantageously, the optical pattern M, in combination with the optical guide array, can enable the implementation of an optical function, such as a filter. The photonic device 1 is generally associated with optical fibers F, forming the inputs / outputs of the device's optical function.

[0060] Thus, and as represented on the photonic devices 1 in figures 5a, 5b, 5c, the optical guide network can comprise a plurality of coupling waveguides Gc, some of which are arranged on one side of the substrate S to form inputs of the photonic device 1 and others on the opposite side of the substrate S, forming outputs of the device 1. It could naturally be envisaged to arrange these coupling waveguides Gc differently, for example on two adjacent sides of the substrate S.

[0061] In this diagram, the optical pattern M forms a ring resonator. As is well known, such a resonator allows for wavelength filtering. The optical pattern M has a ring shape, the radius of curvature of which can be very small, on the order of 50 micrometers, thus enabling a resonant filter with a large free spectral range.

[0062] Figure 1 shows a photonic device implementing a multiplexing / demultiplexing function. This application example takes advantage of the ability to form patterns M with very small radii of curvature to constitute the central pattern M1, thus reducing the size of the device 1. It also exploits the weakly guided nature of light propagation in the glass substrate S, allowing light to be injected into the multitude of waveguides constituting the central pattern M1 with minimal light loss, particularly the light between two waveguides of the central pattern M1.

[0063] Figure 1 presents another example of a photonic device, allowing, for example, adjusting the distance between the optical fibers Fe of an input fiber bundle and the distance between output optical waveguides Fs. These output waveguides can be used, for example, to couple the photonic device with a photonic component, such as a silicon photonic chip. This figure shows that it is possible to configure the waveguides of the optical waveguide array to guide the light radiation not only through the substrate S, but also within the plane of this substrate, along any possible path.

[0064] In the very schematic example shown, the optical pattern is composed of three optical sub-patterns Ma, Mb, and Mc formed from layers of different materials. A wide variety of functions can be integrated onto the same substrate by mixing the materials composing the layers of the sub-patterns.

[0065] Thus, a first material (for example silicon nitride) can be used to form a first sub-motif Ma aimed at forming passive waveguides, a second material (for example lithium niobate) to form a second sub-motif Mb aimed at forming a modulator, and a third material Mc, for example based on Al2O3, to form a third motif Mc aimed at forming an amplifier.

[0066] It is noted that metallic tracks Pe can be provided extending between contact pads Pl and an electrically conductive layer Ce formed on the first layer constituting one of the sub-patterns. In general, a photonic device according to the invention can thus provide for a conductive layer, formed of an electrically conductive material, disposed on the first layer.

[0067] Following the description of the photonic device 1, this one may optionally include a protective cover C. The protective cover has an assembly face G by which it is assembled to the first face of the substrate S. The assembly face C1 is provided with at least one recess E to house the optical motif M. This assembly can be optical in nature (by molecular adhesion and without the need for adhesive) or, alternatively, a layer of adhesive can be placed between the assembly face C1 of the protective cover C and the first face Sa of the substrate S.

[0068] The protective cover C and the substrate S may have identical dimensions at their respective mounting faces. However, advantageously, the mounting face C1 of the protective cover C does not extend over the entire first face Sa of the substrate S. The protective cover C leaves an exposed area of ​​the first face Sa of the substrate S. This exposed area of ​​the first face Sa of the substrate S can be used to position contact pads Pl, connected to a conductive layer formed on a pattern M of the device, as described in relation to [reference missing]. In this configuration, it may be preferable to assemble the protective cover C using an adhesive layer to allow the passage of conductive traces.Thus, when the photonic device 1 is integrated into a more complex system, it can easily be electrically connected to electronic components of that system, even when this photonic device 1 has a protective cover C.

[0069] Advantageously, for reasons of thermal robustness, the protective cover is made of the same material as that constituting the substrate S, in the same glass or in a material having the same coefficient of thermal expansion.

[0070] The protective cover C can have functions other than protecting the fragile parts of the photonic device 1. It can thus be provided that the protective cover C includes at least one complementary waveguide Gc, the latter combining with the waveguide of the substrate, in particular with a coupling waveguide Gc. This configuration is the one shown in Figure 1, in which the assembly interface IA between the protective cover C and the substrate S is shown. The complementary waveguide Gp is ​​arranged in the protective cover C opposite a flush portion of the coupling waveguide Gc, when these two parts are properly assembled at their bonding interfaces. In this way, the coupling of an optical fiber F can be facilitated by providing a combined section of the complementary waveguide Gp and the coupling waveguide Gc closer to the shape of the fiber core.

[0071] When the protective cover C is transparent to light radiation, it can be treated to form an optical element such as a lens L. The optical pattern M can include, beneath this optical element, a surface grating that allows, for example, guiding light radiation passing through the optical element into the first layer defining the pattern or, conversely, guiding light radiation propagating in the first layer defining the pattern towards the optical element. This optional aspect is illustrated in the implementation example.

[0072] This also illustrates the characteristic whereby a protective cover C can provide more than one recess E to protect the optical pattern M, particularly when the latter is composed of a plurality of non-contiguous parts. The spaces separating these non-contiguous parts, which separate the parts of the optical pattern from one another, can allow internal pillars of the protective cover to rest on the first face of the support.

[0073] In other embodiments, the protective cover is formed of a polymer layer. This layer is disposed on at least part of the first face Sa of the substrate S and, advantageously, completely encapsulates the optical pattern M.

[0074] Legally, the support 1 includes an internal waveguide Gi entirely overlaid by the optical pattern M. This internal waveguide Gi can contribute to passively realizing an optical function of the photonic device 1.

[0075] The last three features, although represented on the same page for reasons of conciseness, can naturally be integrated independently of each other in a photonic device 1 according to the invention.

[0076] According to another optional feature of a photonic device 1 according to the invention, shown on the and on the, the optical pattern M can be provided to extend to an edge of the first face of the support S. In this way, this optical pattern M can be directly coupled to an optical fiber F or to an optical component, without going through a coupling waveguide.

[0077] Of course the invention is not limited to the implementation methods described and alternative embodiments can be made without departing from the scope of the invention as defined by the claims.

Claims

Photonic device (1) comprising: a glass substrate (S) having a first face (Sa), a second face (Sb) opposite the first face (Sb), a slice (Sc) connecting the first face (Sa) to the second face (Sb) and incorporating an array of optical guides comprising at least one waveguide (Gc,Gi) capable of propagating an optical mode, the waveguide (Gc,Gi) having a first portion flush with the first face (Sa) of the substrate; a first layer formed of a material capable of propagating light radiation from the optical mode, disposed on the first face (Sa) of the substrate (S) and covering at least part of the first portion of the waveguide (Gc,Gi), the first layer defining, on this first face (Sa), an optical pattern (M) configured to be optically coupled to the waveguide (Gc,Gi) so that the optical mode propagating in the waveguide (Gc,Gi) is transferred into the optical pattern (M). photonic device (1) according to the preceding claim in which at least one waveguide comprises a coupling waveguide (Gc) having a second portion intersecting the slice of the substrate (Sc), the coupling waveguide (Gc) being partly buried in a thickness of the substrate (S). Photonic device (1) according to any one of the preceding claims wherein the at least one waveguide comprises an internal waveguide (Gi) having a first portion and a second portion both flush with the first face (Sa). Photonic device (1) according to the preceding claim in which the internal waveguide (Gi) comprises an intermediate portion embedded in the intermediate portion being disposed between the first portion and the second portion. Photonic device according to any one of the preceding claims wherein the first layer is formed of a material selected from the list consisting of silicon nitride, lithium niobate, silicon, aluminum oxide, indium phosphide. Photonic device (1) according to any one of the preceding claims further comprising a protective cover (C) formed of a polymer layer disposed on at least part of the first face (Sa) and advantageously encapsulating the entire optical pattern (M). Photonic device (1) according to any one of claims 1 to 5 further comprising a protective cover (C) having an assembly face (C1), the protective cover (C) being assembled to the first face (Sa) of the substrate (S) by its assembly face (C1), the assembly face (C1) being provided with at least one recess (E) to house the optical pattern (M). photonic device (1) according to the preceding claim further comprising an adhesive layer between the assembly face (C1) of the protective cover (C) and the first face (Sa) of the substrate (S). Photonic device (1) according to any one of claims 7 and 8 wherein the protective hood (C) comprises at least one complementary waveguide (Gp), the at least one complementary waveguide combining with the second portion of the at least one waveguide (Gc,Gi). Photonic device (1) according to any one of claims 7 to 9 in which the assembly face (C1) of the protective cover (C) does not extend over the entire first face (Sa) of the support (S), and leaves an exposed surface of this first face (Sa). Photonic device (1) according to any one of claims 7 to 10 wherein the protective cover is transparent and comprises at least one optical element such as a lens. Photonic device (1) according to any one of the preceding claims wherein the optical pattern (M) has a tapered or segmented shape overhanging at least in part the first portion of at least one waveguide (Gc,Gi). Photonic device (1) according to any one of the preceding claims wherein the optical pattern (M) is formed of at least two non-contiguous parts and the optical guide array also includes an internal waveguide (Gi) optically coupling the two non-contiguous parts. Photonic device (1) according to any one of the preceding claims wherein the substrate (S) has a U or V groove at the edge (Sc) intersecting the second portion of the waveguide (Gc,Gi). Photonic device (1) according to any one of the preceding claims wherein the optical pattern (M) extends to an edge of the first face (Sa). Photonic system comprising a photonic device (1) according to one of the preceding claims, and at least one optical fiber (F) or a photonic component placed against the edge (Sc) of the substrate (S) opposite the second portion of the coupling waveguide (Gc).

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