Integrated photonic device, corresponding circuit and method

Abstract

The present disclosure relates to integrated photonics devices, corresponding circuits, and methods. An exemplary integrated photonics device can be a thermal phase shifter. An exemplary integrated photonics device includes a substrate of integrated photonics material having an optical waveguide extending therealong and first and second lateral strips extending laterally along and thermally coupled to the optical waveguide; first and second heat transfer members configured to transfer heat from a proximal end, distal from the first and second lateral strips, toward a distal end, thermally coupled to the first and second lateral strips; and first and second electrical heaters thermally coupled to the proximal end of the first and second heat transfer members. Heat generated by the electrical heaters is transferred to the optical waveguide via the heat transfer members and the lateral strips.

Description

Cross-reference to related applications

[0001] This application is a translation of and claims priority to Italian patent application No. 102024000027978, filed on December 10, 2024, entitled “DISPOSITIVO DI FOTONICAINTEGRATA, CIRCUITO E PROCEDIMENTO CORRISPONDENTI”, which is incorporated herein by reference to the fullest extent permitted by law. Technical Field

[0002] This disclosure relates to integrated photonics.

[0003] The technical solution described in this article can be applied to a technology currently known as silicon photonics.

[0004] The technical solution described in this article can be applied to thermal phase shifting in optical waveguides of integrated photonic circuits. Background Technology

[0005] Integrated photonics is an emerging branch of photonics in which waveguides and devices are fabricated as integrated structures on the surface of a flat substrate (flat surface). Complex integrated photonic circuits can process and transmit light in a manner similar to how electronic integrated circuits process and transmit electronic signals.

[0006] The technology currently known as silicon photonics has become a key technology for high-speed optical communication, optical computing, and integrated optical signal processing. Phase shifters represent an important component in these systems, enabling key functions such as beam steering, wavelength routing, and signal modulation.

[0007] Phase shifter architectures that attract research and development activities include thermal and electrical phase shifters, which have distinct advantages and limitations.

[0008] Thermal phase shifters utilize temperature-induced changes in the refractive index of materials to modify the optical path length. They can adjust optical signal characteristics by applying localized heating using integrated resistive elements. Compatibility with standard silicon manufacturing processes and relatively low complexity make thermal phase shifters an advantageous choice among existing technologies.

[0009] Electro-phase shifters utilize the electro-optic effect to modify the optical path by applying an electric field (e.g., by directly manipulating the refractive index or waveguide geometry). Electro-phase shifters facilitate rapid phase shifts, which can inevitably lead to material compatibility issues and insertion loss in silicon photonics platforms.

[0010] Thermal phase shifters demonstrate good integration potential within standard silicon manufacturing processes, providing uniform and predictable phase shifts, and offering significant flexibility in design optimization.

[0011] The inherent material compatibility of thermal methods, combined with their ability to achieve precise phase modulation through a simple heating mechanism, makes thermal phase shifters advantageous for advanced silicon photonics applications, especially where high reproducibility, scalable manufacturing, and consistent optical performance across a variety of operating environments are required.

[0012] Recent developments in thermal phase shifters for silicon photonics have been identified as a foundation for the energy consumption challenges that may limit the performance of photonic circuits. Common thermal phase shifting mechanisms can involve considerable electrical power in generating the thermal gradients used for optical path length modulation.

[0013] The amount of energy involved in the operation can adversely affect the overall circuit efficiency and also introduces thermal management complexities that may hinder accurate optical signal control.

[0014] Existing technologies attempting to reduce power consumption may face challenges related to integration within standard silicon photonics manufacturing processes.

[0015] In fact, various power reduction technologies may involve specialized manufacturing steps or materials that could increase production complexity and device cost. This approach often deviates from established process flows and may face technical and economic hurdles in its implementation.

[0016] Documents (such as, for example, US 2022 / 113564 A1, US 2019 / 004342 A1, US 2005 / 169566 A1, US 2018 / 143462 A1, US 2022 / 197064 A1, US 2019 / 124724 A1 and US 8 461 589 B1) are examples of previous activities in this field. Summary of the Invention

[0017] The purpose of the technical solutions described in this article is to help solve the problems discussed above.

[0018] Such an objective can be achieved via an integrated photonic device having the features set forth in the appended claims.

[0019] The technical solutions described in this article also involve corresponding (integrated) circuits. An integrated photonic thermal phase shifter can be an example of such a circuit.

[0020] The technical solutions described in this article also involve corresponding methods.

[0021] The claims form an integral part of the disclosure of the technical solutions described herein. Attached Figure Description

[0022] The technical solutions according to this disclosure will now be described with reference to the accompanying drawings, which are provided by way of non-limiting example only, and wherein:

[0023] Figure 1A and Figure 1B A thermal phase shifter including a ridge waveguide is shown;

[0024] Figure 2A and Figure 2B A thermal phase shifter including a strip waveguide is shown;

[0025] Figure 3A and Figure 3B A thermal phase shifter including a strip waveguide and trenches is shown;

[0026] Figure 4 This is a plan view of the heat-shifting phase device based on the technical solution proposed in this paper;

[0027] Figure 5A It is along Figure 4 A cross-sectional view of line A-A' in the diagram;

[0028] Figure 5B It is along Figure 4 A cross-sectional view of line B-B' in the diagram;

[0029] Figure 6 This is a flowchart of a method for manufacturing a device according to the technical solution proposed herein;

[0030] Figure 7 A three-dimensional view of the device according to the technical solution proposed herein is shown;

[0031] Figure 8 Exemplary photonic integrated circuits including a thermal phase shifter implemented according to the technical solutions proposed herein are shown; and

[0032] Figure 9 Other examples of photonic integrated circuits, including thermal phase shifters implemented according to the technical solutions proposed herein, are shown. Detailed Implementation

[0033] Numerous specific details are set forth in the following description to provide a thorough understanding of the embodiments. Embodiments may be practiced without one or more of these specific details or by utilizing other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the embodiments.

[0034] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Therefore, the appearance of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any suitable manner in one or more embodiments.

[0035] The headings provided herein are for convenience only and do not explain the scope or meaning of the embodiments.

[0036] In the figures accompanying this document, unless the context otherwise indicates, the same parts or elements are indicated by the same reference numerals / labels, and for the sake of brevity, the corresponding descriptions will not be repeated.

[0037] Additionally, for simplicity and ease of explanation, the same name can be used throughout the description:

[0038] A node or line and the signal appearing at that node or line, and / or

[0039] A component (such as a capacitor or resistor) and its electrical parameters (e.g., capacitance or resistance / impedance).

[0040] When it is mentioned below that a component (optical or electrical ground) is “connected to” or “coupled to” another component, it should be understood that another component may be inserted in between, and that component may also be directly connected to or coupled to another component. Conversely, when it is mentioned that a component (optical or electrical ground) is “directly connected to” or “directly coupled to” another component, it should be understood that no other component is inserted in between.

[0041] Throughout this description, the name "silicon photonics" can be used to refer to the technology currently referred to by that name, because silicon has been, and remains, the integrated photonics material used "superiorly" in most applications based on that technology.

[0042] However, for the sake of brevity, reference to “silicon photonics” (or “silicon photonic materials”) should not be interpreted as implying (or even indirectly) that the technical solutions described herein are strictly limited to the use of silicon as the base material for the integrated photonic devices and circuits proposed herein.

[0043] In Table 1 on page 633 of RJ Deri and E. Kapon, other integrated photonic materials suitable for the technical solutions proposed herein are indicated by way of possible examples: “Low-loss III–V semiconductor optical waveguides”, IEEE J. Quantum Electron., Vol. 27, No. 3, pp. 626-640, March 1991.

[0044] Figure 1A The figure shows a cross-sectional view of the thermal phase shift technology solution applied to waveguide 10.

[0045] As illustrated, waveguide 10 is located on a buried oxide layer 11, which is obtained on top of silicon substrate 12.

[0046] In order to perform thermal phase shift, waveguide 10 includes a first heater 13a and a second heater 13b, which are located outside the waveguide 10 and extend along the entire length of the waveguide 10.

[0047] Heaters 13a and 13b can be obtained by heavily doping the portion of waveguide 10 where heaters 13a and 13b are disposed with electron donor or electron acceptor dopant. Figure 1B As illustrated, the first heater 13a and the second heater 13b receive electrical energy from the first metal via 14a and the second metal via 14b in ohmic contact with them: when a bias voltage is applied through the vias 14a and 14b, current flows through the heaters 13a and 13b, thus generating heat.

[0048] In such an example, heaters 13a and 13b are positioned (too) close to the silicon substrate 12. As indicated by the arrows, only a small fraction of the generated heat is transferred to the waveguide 10, and most of the heat is dispersed within the silicon substrate 12, thus resulting in poor energy efficiency for such a solution.

[0049] Figure 2A Other exemplary technical solutions are illustrated.

[0050] There, a thermal phase shift is applied to the strip waveguide 20. As illustrated, the strip waveguide 20 is located on a buried oxide layer 21, which is obtained on top of a silicon substrate 22.

[0051] To perform thermal phase shift, a metal heater 23 is positioned above the strip waveguide 20, wherein a metal via 24 supplies electrical energy to the metal heater 23, such as... Figure 2B As shown in the diagram.

[0052] Furthermore, this technical solution suffers to varying degrees from the same problems discussed above. For example... Figure 2B As indicated by the arrow, the metal heater 23 heats the large volume oxide layer 21. This results in poor power efficiency because a large amount of heat must be transferred to achieve the desired phase shift.

[0053] Figure 3A Other exemplary techniques for performing thermal phase shifts that exhibit higher power efficiency are illustrated.

[0054] As illustrated, a strip waveguide 30 is disposed on top of a buried oxide layer 31. A trench 35 surrounds the lower cover layer (i.e., the buried oxide layer 31) and the upper cover layer 31b including the strip waveguide 30, such that the trench 35 is filled with air. The trench 35 has a lower sidewall located on top of the silicon substrate 32, while the lateral sidewalls contact the upper cover layer 31b. Figure 3B As shown in the figure, a metal heater 33 is disposed on the top of the overlying layer 31b, and a metal through-hole 34 is provided to supply electrical energy to the metal heater 33.

[0055] This technical solution can achieve higher power efficiency, as long as the air filling the trench 35 promotes thermal insulation between the strip waveguide 30 and the silicon substrate 32.

[0056] The process steps to achieve trenching and undercutting typically involve highly anisotropic etching processes, which can be challenging and expensive to implement in silicon photonics manufacturing processes.

[0057] A slightly similar technical solution is disclosed in document US 2022 / 113564 A1 (already cited), which proposes an integrated chip including waveguide and heater structures.

[0058] In this technical solution, a waveguide is disposed on a substrate and includes an active region extending continuously along a first distance. A heater structure is overlaid on the waveguide and includes a conductive structure above the active region and a vertical structure disposed between the conductive structure and the substrate. The vertical structure includes a conductive upper vertical section and a lower vertical section.

[0059] The conductive structure and the conductive upper vertical segment extend horizontally across a second distance, the second distance being greater than or equal to the first distance, and the first distance being greater than the width of the conductive structure.

[0060] Therefore, a thermal phase-shifting technology solution is desired that can overcome the problems mentioned above and facilitate the implementation of thermal phase shifting in photonic integrated circuits.

[0061] Figure 4 This is a plan view of the heat shifter 100 implemented according to the technical solution proposed in this paper.

[0062] As illustrated, the thermal phase shifter 100 includes a silicon waveguide 110 that extends along a first horizontal direction Y on top of a silicon dioxide layer 106 forming an underlayer of the waveguide 110.

[0063] In addition, the thermal phase shifter 100 includes a pair of heaters 130a and 130b respectively disposed on the left and right sides of the waveguide 110.

[0064] As used herein, “left” and “right” refer to the second horizontal direction X, which is transverse to the “longitudinal” direction Y of the substrate (i.e., the direction of waveguide 100 and heaters 130a and 130b).

[0065] The ends of heaters 130a and 130b are provided with metal contact portions 118a, 118b, 118dc and 118d.

[0066] As shown in the figure, the first heater 130a has a first metal contact portion 118a at one end and a second metal contact portion 118b at the other end.

[0067] Similarly, the second heater 130b has a third metal contact 118c at one end and a fourth metal contact 118d at the other end.

[0068] A pair of trenches (not visible for simplicity) can be provided to enhance the thermal insulation of the silicon substrate from the heat generated by heaters 130a and 130b.

[0069] In various technical solutions, heaters 130a and 130b are electrically coupled to metal contacts 118a, 118b, 118c and 118d by means of metal via arrays 119a and 119b.

[0070] In summary:

[0071] The device 100 proposed herein includes an elongated substrate integrating photonic materials (see the introduction section on the name in this description), the substrate having an optical waveguide 110 extending along the substrate and a first lateral strip 112a and a second lateral strip 112b extending laterally from and thermally coupled to the optical waveguide 110.

[0072] The first heat transfer member 115a and the second heat transfer member 115b (e.g., an array of pillars) are configured to transfer heat from their proximal ends toward their distal ends, the proximal ends being away from the first lateral strip 112a and the second lateral strip 112b in the substrate of the integrated photonics material, and the distal ends being thermally coupled to the first lateral strip 112a and the second lateral strip 112b in the substrate of the integrated photonics material.

[0073] The first electric heater 130a and the second electric heater 130b are thermally coupled to the proximal ends of the first heat transfer member 115a and the second heat transfer member 115b.

[0074] The optical waveguide 110 is thermally coupled to the electric heaters 130a and 130b via heat transfer components 115a and 115b and transverse strips 112a and 112b in the substrate of the integrated photonics material.

[0075] In this manner, the heat generated by the electric heaters 130a and 130b is transferred to the optical waveguide 110 via the following components:

[0076] First heat transfer member 115a and second heat transfer member 115b, and

[0077] The first transverse strip 112a and the second transverse strip 112b in the substrate of the integrated photonics material.

[0078] More in detail, Figure 4 The diagram shows a first cross-section line A-A' and a second cross-section line B-B', wherein the first cross-section line A-A' extends through metal contacts 118a and 118c, metal vias 119a and 119c, heaters 130a and 130b, and ridge waveguide 110, and the second cross-section line B-B' extends through heaters 130a and 130b and waveguide 110.

[0079] Both section lines A-A' and B-B' extend along the second horizontal direction X.

[0080] Figure 5A The figure shows a cross-sectional view of the heat-shifting phase device 100 corresponding to the first cross-sectional line A-A'.

[0081] As illustrated, silicon waveguide 110 is disposed on top of silicon dioxide underlayer 106. In addition to silicon waveguide 110, thermal phase shifter 100 also includes a first silicon strip 112a and a second silicon strip 112b, which are positioned laterally to the waveguide 110 and may protrude slightly at the leftmost and rightmost ends of the substrate (upward in the "vertical" Z direction).

[0082] There, an array of metal (e.g., copper) pillars 115a and 115b is provided. These metal pillars 115a and 115b provide a first heat transfer member and a second heat transfer member extending along axis Z (and thus transverse to the substrate plane identified by directions X and Y), and optionally are bonded to silicon strips 112a and 112b by means of silicide layers 116a and 116b.

[0083] In various technical solutions, silicide layers 116a and 116b include nickel silicide.

[0084] The upper portion of each metal post 115a and 115b is joined to metal pads 117a and 117b. The cross-section of metal pads 117a and 117b is larger than the cross-section of metal posts 116a and 116b (that is, the enlarged head portion of posts 116a and 116b).

[0085] Metal pads 117a and 117b are separated from heaters 130a and 130b by gaps.

[0086] In this manner, heaters 130a and 130b can conduct heat through gaps to metal pads 117a and 117b, which in turn conduct heat to the underlying metal pillars 115a and 115b. In various technical solutions, the gaps are filled with oxides (e.g., silicon dioxide) that can be bonded to the overlay 107 of the silicon waveguide 110.

[0087] It should be noted that using silicon dioxide (SiO2) for gap insulation is advantageous, but not strictly mandatory. In principle, even an air gap is feasible, but due to the small distance between two conductors that should not be in contact with each other, such a choice may ultimately be unreliable.

[0088] Heaters 130a and 130b are electrically coupled to metal contacts 118a and 118b via metal vias 119a and 119b.

[0089] refer to Figure 4 Electrical contacts 118a, 118b, 118c and 118d are configured such that a bias voltage can be applied to heaters 130a and 130b along the first horizontal direction Y.

[0090] Figure 5B The figure shows a cross-sectional view of the thermal phase shifter 100 along line B-B'.

[0091] As illustrated, the second cross-section line B-B' does not cross any metal contacts (such as metal contacts 118a and 118c), but only crosses the heaters 130a and 130b, the metal pillars in the array of metal pillars 115a, the metal pillars in the opposite array of metal pillars 118b, and the silicon waveguide 110.

[0092] As described, metal pads 117a and 117b are separated from heaters 130a and 130b by a relatively short gap, thereby allowing heaters 130a and 130b to transfer heat to metal pads 117a and 117b.

[0093] With this arrangement, heaters 130a and 130b form two resistors, each having a first terminal located at metal contacts 118a and 118c, and a second terminal located at metal contacts 118b and 118d, respectively. In this way, heaters 130a and 130b generate heat when an electric current passes through them.

[0094] It should be noted that the materials used to achieve the structures described in this article are advantageous because they can be readily used within standard silicon photonics manufacturing processes.

[0095] In fact, the materials involved include titanium nitride (TiN) for realizing heaters 130a and 130b, nickel silicide (NiSi) for bonding metal pillars 115a and 115b to silicon strips 112a and 112b, and copper for realizing metal pillars 115a and 115b, metal pads 117a and 117b, metal contacts 118a, 118b, 118c and 118d, and metal vias 119a and 119b.

[0096] By employing different materials, alternatives to the technical solutions described in this paper become possible.

[0097] In this respect, such a design can be advantageous because the metal pillars 115a and 115b are primarily used for heat conduction rather than electrical conduction, and a wide range of materials can be used to bond the metal pillars 115a and 115b to the corresponding silicon ridges 112a and 112b without needing to ensure carrier transport across the silicon / silicide junction.

[0098] As indicated by arrow H representing heat flow (through radiation and / or conduction) Figure 5B As illustrated, the heat generated at heaters 130a and 130b flows through the gaps, metal pads 117a and 117b, and metal pillars 115a and 115b to reach silicon waveguide 110, while advantageously reducing the heat transferred to other parts of the thermal phase shifter 100, where heat does not serve any desired purpose and may even be harmful.

[0099] In fact, thanks to the higher thermal conductivity of the metal pads 117a and 117b relative to the silicon dioxide forming the underlayer 106 and the overlayer 107, heat is efficiently transferred to the waveguide 110.

[0100] As described, the overlay 107 may be made of silicon dioxide and cover the waveguide 110. In addition, in various technical solutions, the overlay 107 may contain one or more components of the thermal phase shifter 100, such as, for example, metal pillar arrays 115a and 115b, metal pads 117a and 117b, and heaters 130a and 130b.

[0101] In summary, as illustrated herein, the first heat transfer member 115a and the second heat transfer member 115b comprise an array of heat-conducting pillars having:

[0102] The first lateral stripe 112a and the second lateral stripe 112b in the substrate of the integrated photonics material are located near the substrate.

[0103] At the far end, a first transverse strip 112a and a second transverse strip 112b are thermally coupled to a substrate of integrated photonics material.

[0104] As illustrated herein, the first heat transfer member 115a and the second heat transfer member 115b comprise conductive material (optionally, copper) disposed between the following portions without contact (i.e., at a distance):

[0105] The first electric heater and the second (130b) electric heater (130a, 130b), and

[0106] The proximal ends of the first heat transfer member and the second heat transfer member (an array of columns 115a and 115b).

[0107] Advantageously, thermally conductive elements (such as those indicated by reference numerals 117a and 117b) provide an advantageous (non-contact or "no-contact") heat transfer path between the electric heaters 130a, 130b and the proximal ends of the columns 115a, 115b.

[0108] These thermally conductive components 117a, 117b advantageously comprise the same thermally conductive material (e.g., copper) as the first and second heat transfer components (an array of pillars 115a, 115b).

[0109] More advantageously, the power supply terminals 118a, 118b, 118c, 118d for the electric heaters 130a, 130b can be provided together with an array of conductive vias 119a, 119b, 119c, 119d that couple the power supply terminals 118a, 118b, 118c, 118d to the electric heaters 130a, 130b.

[0110] As illustrated, electric heaters 130a and 130b have an elongated shape between their opposite ends, and the power terminals 118a, 118b, 118c, and 118d that are coupled to the electric heaters 130a and 130b vias 119a, 119b, 119c, and 119d are advantageously (only) arranged at the opposite ends of such an elongated shape, while the heat-conducting members 117a and 117b are distributed along the (entire) length of the elongated shape.

[0111] This can be achieved through comparison. Figure 5A and Figure 5B Let's understand the internal gap between heaters 130a and 130b (in Figure 5B (marked as G) along with the width of the heater (in) Figure 5B The width marked W is visible at the ends where power terminals 118a, 118b, 118c, and 118d are located. Figure 5A (See the middle) The area is relatively large.

[0112] As illustrated, optionally, a nickel silicide heat transfer material (see reference numerals 116a, 116b) is inserted between the distal ends of the first and second heat transfer components (pillars 115a, 115b) and the first and second transverse strips 112a and 112b in the substrate of the integrated photonics material.

[0113] Figure 6 This is a flowchart illustrating a method 600 for manufacturing a thermal phase shifter 100 as described above.

[0114] After the initial step (where, for example, a silicon substrate on an insulator is set, i.e., a silicon substrate including a buried silicon dioxide layer), in the first step 601, a silicon waveguide 110 and silicon ridges 112a and 112b are obtained by means of an etching process, the waveguide 110 and silicon ridges 112a and 112b extending along a first horizontal direction Y.

[0115] In step 602, silicide bonding layers 116a and 116b are achieved by means of a first intermediate step and a second intermediate step, the first intermediate step including depositing nickel or other metal over silicon ridges 112a and 112b, and the second intermediate step including thermal annealing for forming silicide bonding layers 116a and 116b by silicide reaction.

[0116] In stage 603, metal pillars 115a and 115b are fabricated on top of the corresponding silicide bonding layers 116a and 116b obtained in the previous step 602. As mentioned above, the metal pillars 115a and 115b can be implemented using copper or other transition metals.

[0117] In stage 604, metal pads 117a and 117b are obtained on top of metal pillars 115a and 115b. Alternatively, in this case, metal pads 117a and 117b can be implemented using copper or other transition metals.

[0118] Step 605 includes forming heaters 130a and 130b on top of the previously obtained metal pads 117a and 117b. Specifically, heaters 130a and 130b are implemented using titanium nitride, with a gap between the top of the metal pads 117a and 117b and the bottom surface of the heaters 130a and 130b. In this way, as previously described, the heat generated by heaters 130a and 130b is transferred to the metal pads 117a and 117b by conduction, while reducing undesirable temperature rise in other parts of the photonic integrated circuit. Specifically, the generated heat is transferred by conduction across the gap-filling material, which may be silicon dioxide forming the overlay 107.

[0119] In step 606, metal vias 119a, 119b, 119c, and 119d are provided on top of heaters 130a and 130b to allow for proper electrical biasing. Similar to metal pillars 115a and 115b and metal pads 117a and 117b, the metal vias 119a, 119b, 119c, and 119d can be implemented using copper or alternatively, other transition metals.

[0120] In step 607, metal contacts 119a, 119b, 119c, and 119d are provided on top of the respective metal via arrays 119a, 119b, 119c, and 119d to allow electrical access to heaters 130a and 130b. Alternatively, in this case, the metal contacts 119a, 119b, 119c, and 119d can be implemented using copper or other transition metals.

[0121] In step 608, a drilling step is performed to obtain a first trench and a second trench on the respective sides of the thermal phase shifter 100 to increase thermal insulation with the substrate. This trenching step is optional.

[0122] At the end of step 608, a finished thermal phase shifter 100 is obtained according to the technical solution described herein.

[0123] Furthermore, it should be understood that, Figure 6 The sequence of steps in the example is merely exemplary because:

[0124] Figure 6 One or more steps illustrated may be omitted, performed in a different manner (e.g., using other tools), and / or replaced with other steps;

[0125] Additional steps that could be added for brevity include: for example, depositing one or more oxides before / after setting the metal layer and vias; and

[0126] One or more steps may be performed in a sequence different from the sequence illustrated.

[0127] In conclusion, such as Figure 6 The methods illustrated in the flowchart include:

[0128] An elongated substrate for integrating photonic materials is provided (see step 601), the substrate having an optical waveguide 110 extending thereal and a first lateral strip 112a and a second lateral strip 112b extending laterally in and thermally coupled thereto from the optical waveguide 110.

[0129] Growth (see steps 602, 603, 604) of a first heat transfer member and a second heat transfer member (pillars 115a, 115b), the first and second heat transfer members being configured to transfer heat from a proximal end to a distal end, the proximal end being away from the first lateral stripe 112a and the second lateral stripe 112b in the substrate of the integrated photonics material, and the distal end being thermally coupled to the first lateral stripe 112a and the second lateral stripe 112b in the substrate of the integrated photonics material; and

[0130] A first electric heater 130a and a second electric heater 130b are configured (see steps 605, 606, 607) to be thermally coupled to the proximal ends of the first heat transfer member 115a and the second heat transfer member 115b, wherein the optical waveguide 110 is thermally coupled to the first electric heater 130a and the second electric heater 130b via the first heat transfer member and the second heat transfer member (pillars 115a, 115b) and the first lateral strip 112a and the second lateral strip 112b in the substrate of the integrated photonics material.

[0131] Therefore, the heat generated by the electric heaters 130a and 130b is transferred to the optical waveguide 110 via the following portion:

[0132] The first heat transfer component and the second heat transfer component (pillars 115a, 115b) and the first lateral stripe 112a and the second lateral stripe 112b in the substrate of the integrated photonics material.

[0133] Figure 7 It is a three-dimensional view of the integrated photonic device 100 that can be obtained as a result of manufacturing method 600.

[0134] In the illustrated example, the upper (relative to the first direction Y) metal contacts 118a and 118c are obtained by means of a single metal strip. The same applies to the lower metal contacts 118b and 118d relative to the first horizontal direction Y. In this way, heaters 130a and 130c can be easily subjected to the same voltage, and the same conditions are also applied to the lower metal contacts 118c and 118d, thus contributing to uniform heating of heaters 130a and 130b.

[0135] Those skilled in the art will understand that the manufacturing steps described above are suitable for easy integration into silicon photonics manufacturing processes without employing more complex steps, such as highly anisotropic etching for performing undercuts.

[0136] Given these advantages, the thermal phase shifter 100 described herein can be used in a wide range of photonic integrated circuits.

[0137] Figure 8 The illustration shows a first exemplary photonic integrated circuit 800 that implements a fully integrated photonic coherent transceiver. In the example shown, two thermal phase shifters 100 are optically coupled to a “1” symbol modulator circuit MOD and are located in portions configured to support the processing of x-polarized signals and y-polarized signals, respectively.

[0138] As illustrated, the transceiver 800 also includes two 90-degree mixing circuits 810 in the receiver section RX, which are configured to support the processing of x-polarized signals and y-polarized signals, respectively. The x-polarized signals and y-polarized signals are electrically coupled to a transimpedance amplifier circuit 820 via a photodetector, which is then coupled to a digital signal processor (DSP) circuit 830.

[0139] Similarly, DSP circuitry 830 is disposed in the transmitter section TX, which is electrically coupled to driver circuitry 840. Driver circuitry 840, in turn, is coupled to modulator circuitry MOD.

[0140] Figure 9 A second exemplary photonic integrated circuit for implementing a thermal switch is illustrated. In the example shown, the circuit includes a thermal phase shifter 100, which further includes a ring-shaped heating element and a waveguide of a similar shape. Furthermore, in this case, by applying the techniques described herein to the illustrated circuit, advantages may include better power and thermal efficiency.

[0141] all in all, Figure 8 and Figure 9 Both are examples of circuits 800 including device 100 as previously discussed, wherein optical waveguide 110 in integrated photonic materials is configured to provide a path for light radiation to propagate along it.

[0142] The heat generated by the first electric heater 130a and the second electric heater 130b and transferred to the optical waveguide 110 via the heat transfer members (pillars 115a, 115b) and the transverse strips 112a, 112b in the substrate of the integrated photonics material provides the desired phase shift in the light radiation propagating along the optical waveguide 110 in the integrated photonics material.

[0143] In summary, the technical solutions described herein advantageously facilitate increased thermal and power efficiency in thermally phase-shifter integrated photonic devices while maintaining sufficient process complexity to facilitate the use of existing available functionalities.

[0144] The technical solutions proposed in this paper further promote cost-effective implementation methods. In addition to more complex and costly integrated photonic devices, these implementation methods can be further utilized to increase the efficiency of related photonic integrated circuits.

[0145] Without prejudice to the fundamental principles or departing from the limits of protection, the details and embodiments may vary significantly from what has been described by way of example only.

[0146] The limits of protection are determined by the appended claims.

Claims

1. A device comprising: A substrate integrating photonic materials, the substrate having an optical waveguide extending along the substrate, and a first lateral stripe and a second lateral stripe extending laterally along the optical waveguide and thermally coupled to the optical waveguide; A first heat transfer member and a second heat transfer member, configured to transfer heat from a proximal end to a distal end, the proximal end being remote from the first and second lateral stripes in the substrate of the integrated photonics material, and the distal end being thermally coupled to the first and second lateral stripes in the substrate of the integrated photonics material; and A first electric heater and a second electric heater, the first electric heater and the second electric heater being thermally coupled to the proximal ends of the first heat transfer member and the second heat transfer member, wherein the optical waveguide is thermally coupled to the first electric heater and the second electric heater via the first heat transfer member and the second heat transfer member and the first lateral stripe and the second lateral stripe in the substrate of the integrated photonics material.

2. The device of claim 1, wherein the first heat transfer member and the second heat transfer member comprise an array of heat-conducting pillars having a proximal end and a distal end, the proximal end being remote from the first lateral stripe and the second lateral stripe in the substrate of the integrated photonics material, and the distal end being thermally coupled to the first lateral stripe and the second lateral stripe in the substrate of the integrated photonics material.

3. The device according to claim 1, wherein the first heat transfer member and the second heat transfer member comprise a conductive material, preferably copper, the conductive material being disposed non-contactly between the proximal end of the first heat transfer member and the proximal end of the second heat transfer member and the first electric heater and the second electric heater.

4. The device of claim 1, wherein the first heat transfer member and the second heat transfer member comprise a thermally conductive member that provides a favorable heat transfer path between the first electric heater and the second electric heater and the proximal end of the first heat transfer member and the second heat transfer member, wherein the thermally conductive member preferably comprises the same thermally conductive material as the first heat transfer member and the second heat transfer member.

5. The device of claim 4, comprising a power supply terminal for the first electric heater and the second electric heater, and a conductive via coupling the power supply terminal to the first electric heater and the second electric heater.

6. The device according to claim 5, wherein: The first electric heater and the second electric heater have an elongated shape between their opposite ends; The conductive vias that couple the power terminals to the first and second electric heaters are arranged at opposite ends of the elongated shape. as well as The heat-conducting components are distributed within the length of the elongated shape between the opposite ends.

7. The device of claim 1, comprising a heat transfer material between the distal ends of the first heat transfer member and the second heat transfer member and the substrate of the integrated photonics material, wherein the heat transfer material preferably comprises nickel silicide.

8. A circuit comprising the device of claim 1, wherein the optical waveguide in the integrated photonic material is configured to provide a path for optical radiation to propagate along the path, wherein heat generated by the first electric heater and the second electric heater and transferred to the optical waveguide via the first heat transfer member and the second heat transfer member and the first lateral stripe and the second lateral stripe in the substrate of the integrated photonic material provides a phase shift in the optical radiation propagating along the optical waveguide in the integrated photonic material.

9. A method comprising: A substrate for integrating photonic materials is provided, the substrate having an optical waveguide extending along the substrate and a first lateral stripe and a second lateral stripe extending laterally along the optical waveguide and thermally coupled to the optical waveguide; A first heat transfer member and a second heat transfer member are grown, the first heat transfer member and the second heat transfer member being configured to transfer heat from a proximal end to a distal end, the proximal end being remote from the first lateral stripe and the second lateral stripe in the substrate of the integrated photonics material, and the distal end being thermally coupled to the first lateral stripe and the second lateral stripe in the substrate of the integrated photonics material; and A first electric heater and a second electric heater are provided, the first electric heater and the second electric heater being thermally coupled to the proximal ends of the first heat transfer member and the second heat transfer member, wherein the optical waveguide is thermally coupled to the first electric heater and the second electric heater via the first heat transfer member and the second heat transfer member and the first lateral stripe and the second lateral stripe in the substrate of the integrated photonics material.

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