FR3165086A1 - A photonic device comprising a glass substrate and an optical pattern placed on the substrate. - Google Patents

Abstract

The invention relates to a photonic device (1) comprising a glass substrate (S) incorporating an array of optical waveguides. This array comprises at least one waveguide (Gc), referred to as the "coupling waveguide," having a first portion flush with a face (Sa) of the substrate (S) and a second portion intersecting the edge (Sc) of the substrate (S). The photonic device (1) also comprises a first layer formed of a material capable of propagating light radiation. The first layer at least partially covers the first portion of the coupling waveguide. The first layer defines an optical pattern (M) optically coupled to the array of optical waveguides. Figure 1

Description

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

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

The document by Broquin et al "Integrated Photonics on Glass: A Review of the Ion-Exchange Technology Achievements" Applied Sciences 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.

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.

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.

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.

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

SUBJECT OF THE INVENTION

One aim of the invention is to provide a photonic device that takes advantage of the listed benefits of a glass platform.

BRIEF DESCRIPTION OF THE INVENTION

• un substrat en verre présentant une première face, une seconde face opposée à la première face, une tranche reliant la première face à la seconde face et incorporant un réseau de guides optiques comprenant au moins un guide d’onde, dit « de couplage », présentant une première portion affleurant la première face et une deuxième portion intersectant la tranche du substrat;
• une première couche formée d’un matériau apte à propager un rayonnement lumineux disposée sur la première face du substrat et recouvrant au moins en partie la première portion du guide d’onde de couplage, la couche définissant, sur cette première face, un motif optique optiquement couplé au réseau de guide optique.

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 including at least one waveguide, called a "coupling" waveguide, having a first portion flush with the first face and a second portion intersecting the slice of the substrate;
• a first layer made of a material capable of propagating light radiation arranged on the first face of the substrate and covering at least part of the first portion of the coupling waveguide, the layer defining, on this first face, an optical pattern optically coupled to the optical guide network.

• le guide d’onde de couplage est en partie enfoui dans une épaisseur du substrat ;
• la première couche est formée d’un matériau choisi dans la liste constituée du nitrure de silicium, du niobate de lithium, du silicium, de l’oxyde d’aluminium, du phosphure d’indium ;
• le dispositif photonique comprend, en outre, un capot de protection présentant une face d’assemblage, le capot de protection étant assemblé à la première face du substrat par sa face d’assemblage, la face d’assemblage étant muni d’au moins un évidemment pour loger le motif optique ;
• le capot de protection est constitué du même matériau que celui constituant le substrat ou d’un matériau présentant le même coefficient de dilatation thermique ;
• le dispositif photonique comprend, en outre, une couche d’adhésif entre la face d’assemblage du capot de protection et la première face du substrat ;
• le capot de protection comprend au moins un guide d’onde complémentaire, le au moins un guide d’onde complémentaire se combinant avec la deuxième portion du guide d’onde de couplage du support ;
• la face d’assemblage du capot de protection ne s’étend pas sur toute la première face du support, et dégage une surface exposée de cette première face ;
• le capot de protection est transparent et comporte au moins un élément optique tel qu’une lentille ;
• le motif optique présente une forme effilée ou segmentée surplombant au moins en partie la première portion du guide d’onde de couplage ;
• le motif optique comprend un guide d’onde à bande ou à nervure ;
• le motif optique met en œuvre une fonction optique, tel qu’un filtre ;
• le réseau de guides optiques comprend également au moins un guide d’onde interne présentant une première portion et une deuxième portion affleurant l’une et l’autre la première face et un portion intermédiaire enfouie dans le substrat, la portion intermédiaire étant disposée entre la première portion et la deuxième portion.
• le motif optique est formé d’au moins deux parties non jointives et le réseau de guides optiques comprend également un guide d’onde interne couplant optiquement les deux parties non jointives ;
• le réseau de guides optiques comprend également un guide d’onde interne entièrement surplombé par le motif optique ;
• le substrat présente une rainure en U ou en V sur au niveau de la tranche intersectant la deuxième portion du guide d’onde pour recevoir l’extrémité d’une fibre optique ;
• le motif optique s’étend jusqu’à un bord de la première face ;
• le réseau de guides optiques comprend une pluralité de guides d’onde de couplage, une partie étant disposée d’un côté du substrat et une autre partie étant disposée du côté opposé du substrat.

According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination:

• the coupling waveguide is partially embedded within a thickness of the substrate;
• the first layer is formed of a material chosen from the list consisting of silicon nitride, lithium niobate, silicon, aluminium oxide, indium phosphide;
• the photonic device further includes 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 the substrate or of a material having the same coefficient of thermal expansion;
• the photonic device further includes an adhesive layer between the assembly face of the protective cover and the first face of the substrate;
• the protective cover includes at least one complementary waveguide, the at least one complementary waveguide combining with the second portion of the coupling waveguide of the support;
• the assembly face of the protective cover does not extend over the entire first face of the support, 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 overhanging at least part of 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 guide array also includes at least one internal waveguide having a first portion and a second portion both flush with the first face and an intermediate portion buried in the substrate, the intermediate portion being disposed between the first portion and the second portion.
• 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 entirely overhung by the optical pattern;
• the substrate has a U or V shaped groove on the edge intersecting the second portion of the waveguide to receive the end of an optical fiber;
• the optical pattern extends to one 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.

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.

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:

FIG. 1

There FIG. 1 illustrates a photonic device according to the invention;

FIG. 2

There FIG. 2 represents a substrate of a photonic device incorporating an array of optical guides in top view and according to section AA;

FIG. 2

There FIG. 2 represents the substrate of the FIG. 2 according to section BB of this figure;

FIG. 3

There FIG. 3 illustrates two approaches to coupling an optical fiber to a photonic device according to the invention;

FIG. 4

FIG. 4

Figures 4a and 4b illustrate different modes of propagation of light radiation in an optical pattern of a device according to the invention;

FIG. 5

FIG. 5

FIG. 5

FIG. 5

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

FIG. 6

There FIG. 6 illustrates an implementation method in which a protective cover for a photonic device according to the invention presents a complementary waveguide;

FIG. 7

FIG. 8

Figures 7 and 8 illustrate other characteristics of a photonic device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

There FIG. 1 represents, by way of illustration, a photonic device 1 according to the invention.

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.

Without this constituting a limitation and for illustrative purposes only, the thickness of the substrate can be between 500 microns and 1 mm. It can extend in a plane and take a rectangular shape in that plane, and extend over a surface typically ranging from a few mm^2 to a few cm^2.

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.

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.

As has been made visible on the FIG. 2 The substrate S incorporates an array of optical guides. This array of optical guides is designed to propagate light radiation within the photonic device 1. In this illustration, the optical guide array is formed by a plurality of waveguides, each waveguide being defined within the thickness of the substrate as a volume exhibiting a refractive index different from the rest of the substrate. This refractive index guides the propagation of light radiation within the substrate S.

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.

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

A coupling waveguide Gc is intended to propagate light radiation from or to 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 that intersects the edge, in a "butt-to-end" coupling configuration ("Butt Coupling", according to the Anglo-Saxon terminology of the field). This assembly can be facilitated by placing on the first face Sa of the substrate a piece forming a mechanical stop for the end of the fiber, which facilitates the precise positioning and adhesion of this fiber, particularly when the coupling waveguide is flush with the first face Sa of the substrate S. Alternatively, a U or V groove can be formed on the edge of the substrate, at the level of the portion of the coupling waveguide that intersects the edge, this groove allowing the fiber to be positioned precisely so that its core is aligned with the coupling waveguide.

It should be noted that the coupling of an optical fiber to a glass substrate 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.

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.

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, as will be detailed later. The cross-section of the waveguide at its flush portion has a general elliptical shape, as shown in the FIG. 2 .

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 in the substrate 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 the FIG. 2 Burying a portion of the waveguide is beneficial for preserving the quality of light radiation that may propagate through it. This prevents the light radiation from interacting with elements that might be present on the first face Sa of the substrate S during its propagation.

This was thus represented on the FIG. 2 A coupling waveguide Gc1 consists of a first exposed portion and a second buried portion, the latter intersecting the substrate's Sc layer. Another coupling waveguide Gc2 and an internal waveguide Gi2, each consisting of a single exposed portion, are also shown. An internal waveguide Gi, when it has a buried portion, also has two exposed portions, positioned on either side of the buried portion.

The optical guide array incorporated into the substrate S can combine any type of coupling and internal waveguide, 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 coupling waveguide Gc, thus formed of a portion flush with the first face and a portion intersecting the Sc slice of the substrate S. This portion intersecting the Sc slice can be flush or buried.

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. It results in the definition of surface regions within the volume of the substrate S that have a refractive index different from the rest of the substrate S.

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.

Other methods for manufacturing 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 of the substrate S, can thus be formed by laser treatment of this face.

Continuing the description of the photonic device 1 illustrated on the FIG. 1 This layer comprises a first layer placed on and in contact with the first face Sa of the substrate S. The first layer at least partially covers the flush portion of the coupling waveguide Gc. More generally, the first layer at least partially covers the flush portions 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 optically coupled to the optical guide array, meaning that light propagating in the optical guide array is also able to propagate in the optical pattern M.

The first layer is therefore made of a material capable of propagating light. 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.

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.

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.

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. This thickness is not necessarily uniform over its entire extent and the first layer may be structured to present areas of distinct thicknesses.

The optical pattern M is suitable for guiding light radiation to or from the optical guide array of the support. To this end, the optical pattern M advantageously has a tapered shape Ze or is segmented and overhangs at least part of the flush portions of the waveguides of the optical guide array.

Figures 4a and 4b thus represent different possible implementation methods of the optical motif M incorporating such tapered Ze shapes. On the FIG. 4 And as can be seen in the cross-section of this figure, light radiation propagates entirely guided and confined within the optical pattern M, that is, within the thickness of the first layer. This optical pattern can thus include a band waveguide (left cross-section of the FIG. 4 ) or ribbed (right-hand cut on the FIG. 4 ). On the cut of the FIG. 4 , the light radiation is not entirely confined within the optical pattern M, and a part of this radiation is weakly guided into the glass substrate S, in a surface thickness arranged directly below the optical pattern M.

It is noted that the optical pattern M can be configured, notably by defining the width (the dimension transverse to the direction of propagation of the light radiation) 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 a pattern 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.

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 is generally associated with optical fibers F, forming the inputs/outputs of the device's optical function.

Thus, and as represented on the photonic devices in figures 5a, 5b, 5c, the optical guide network can include a plurality of coupling waveguides, one part being arranged on one side of the substrate S to form inputs of the photonic device 1 and another part being arranged on the opposite side of the substrate S, and forming outputs of the device 1. It could naturally be envisaged to arrange these coupling waveguides differently, for example on two adjacent sides of the substrate S.

On the FIG. 5 The optical pattern M forms a ring resonator. As is well known, such a resonator allows for a wavelength filtering function.

On the FIG. 5 A photonic device 1 implementing a multiplexing/demultiplexing function is shown. 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 benefits from 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.

There FIG. 5 Figure 1 presents another example of a photonic device, allowing, for example, the adjustment of the distance between the optical fibers Fe of an input optical fiber bundle and the distance between the output optical waveguides Fs. These output waveguides can, for example, be used 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 depth of the substrate S, but also within the plane of this substrate, along any possible path.

Using the very schematic example of the FIG. 5 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.

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.

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.

Continuing the description of the photonic device 1 of the FIG. 1 This 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 accommodate the optical motif M. This assembly may be optical in nature (by molecular adhesion and without the need for adhesive) or, alternatively, a layer of adhesive may be provided between the assembly face C1 of the protective cover C and the first face Sa of the substrate S.

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 presented in relation to the FIG. 5 . 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.

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.

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 at least one complementary waveguide combining with the support waveguide, in particular with a coupling waveguide Gc. This configuration is the one shown in the diagram. FIG. 6 in which the existing assembly interface IA between the protective cover C and the substrate S is materialized. The complementary waveguide Gp is arranged in the protective cover C opposite a flush portion of the coupling guide Gc, when these two parts are properly assembled to each other at their bonding interfaces. This facilitates the coupling of an optical fiber F by providing a combined cross-section of the complementary waveguide Gp and the coupling guide Gc that more closely resembles the shape of the fiber core.

When the protective cover C is transparent to light, 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 passing through the optical element into the first layer defining the pattern or, conversely, guiding light propagating in the first layer defining the pattern towards the optical element. This optional aspect is illustrated in the implementation example of the FIG. 7 .

This FIG. 7 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.

On the FIG. 7 Also, 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.

The last three characteristics, although represented on the same FIG. 7 For reasons of brevity, they can naturally be integrated independently of each other in a photonic device according to the invention.

According to another optional feature of a photonic device according to the invention, shown in the FIG. 8 , we can predict that the optical pattern M extends to an edge of the first face of the support S. In this way we can directly couple this optical pattern M to an optical fiber F or to an optical component, without going through a coupling waveguide.

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 (15)

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 optical guide array comprising at least one waveguide (Gc), called "coupling", having a first portion flush with the first face (Sa) and a second portion intersecting the slice of the substrate (Sc);
• a first layer made of a material capable of propagating light radiation arranged on the first face (Sa) of the substrate (S) and covering at least part of the first portion of the coupling waveguide (Gc), the layer defining, on this first face (Sa), an optical pattern (M) optically coupled to the optical guide network.

Photonic device (1) according to the preceding claim in which the coupling waveguide (Gc) is partly embedded in a thickness of the substrate (S). 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) 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 4 and 5 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 coupling waveguide (Gc). Photonic device (1) according to any one of claims 4 to 6 wherein 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 4 to 7 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 the coupling waveguide (Gc). Photonic device (1) according to any one of the preceding claims wherein the optical guide array also comprises at least one internal waveguide (Gi) having a first portion and a second portion both flush with the first face (Sa) and an intermediate portion buried in the substrate (S), the intermediate portion being disposed between the first portion and the second portion. Photonic device (1) according to the preceding claim in which 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 claims 10 and 11 wherein the optical guide array also includes an internal waveguide (Gi) entirely overridden by the optical pattern (M). 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 coupling waveguide (Gc). 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).