Low-loss and high-efficiency optical phase shifter

Abstract

The disclosed photonic device includes a first cladding layer, a first electrical contact including a first lead coupled to a first dielectric portion, a second electrical contact including a second lead coupled to a second dielectric portion, a waveguide structure including a slab layer comprising a first material, and a second cladding layer. The slab layer may be coupled to the first dielectric portion of the first electrical contact and the second dielectric portion of the second electrical contact. The dielectric constants of the first dielectric portion and the second dielectric portion may be greater than the dielectric constant of the first material.

Description

[0001] Priority Claim

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 967,166, filed on January 29, 2020, titled "Low Loss High Efficiency Photonic Phase Shifter", which is hereby incorporated by reference in its entirety as if fully and completely set forth herein. Field of Technology

[0003] Embodiments herein generally relate to electro-optic devices such as phase shifters and switches. Background Art

[0004] Electro-optic (EO) modulators and switches have been used in the optical field. Some EO modulators utilize free carrier electrorefraction, free carrier electroabsorption, or the DC Kerr effect to modify optical properties during operation, e.g., to change the phase of light propagating through the EO modulator or switch. As an example, optical phase modulators can be used in integrated optical systems, waveguide structures, and integrated optoelectronic devices.

[0005] Despite progress in the field of EO modulators and switches, there is a need in the art for improved methods and systems related to EO modulators and switches. Summary of the Invention

[0006] Some embodiments described herein relate to photonic devices such as electro-optic switches and phase shifters. The device can include a first cladding layer, a first electrical contact including a first lead coupled to a first dielectric portion, a second electrical contact including a second lead coupled to a second dielectric portion, a waveguide structure including a slab layer comprising a first material, and a second cladding layer. The slab layer can be coupled to the first dielectric portion of the first electrical contact and the second dielectric portion of the second electrical contact.

[0007] The dielectric constants of the first dielectric portion and the second dielectric portion can be greater than the dielectric constant of the first material in the direction separating the first dielectric portion and the second dielectric portion. At a first temperature greater than 1 mK, less than 77 K, less than 150 K, and / or within another temperature range, the dielectric constants of the first dielectric portion and the second dielectric portion can be greater than the dielectric constant of the first material. In some embodiments, the first material is a transparent material having a refractive index greater than the refractive indices of the first cladding layer and the second cladding layer. In some embodiments, the ratio of the dielectric constants of the first dielectric portion and the second dielectric portion to the dielectric constant of the first material is 2 or greater.

[0008] The waveguide structure may include a first ridge portion that includes a first material and is coupled to a slab layer, where the first ridge portion is disposed between a first electrical contact and a second electrical contact. The ridge portion may be disposed on a first side of the slab layer and may extend into a first cladding layer, and a first dielectric portion and a second dielectric portion may be coupled to the slab layer on a first side of the slab layer adjacent to the ridge portion of the waveguide structure.

[0009] In other embodiments, the ridge portion is disposed on a first side of the slab layer and extends into a first cladding layer, where the first dielectric portion and the second dielectric portion are coupled to the slab layer on a second side of the slab layer opposite the first side. In some embodiments, the first electrical contact and the second electrical contact are disposed on the second side of the slab layer.

[0010] In some embodiments, the first electrical contact is coupled to the first dielectric portion by passing through the slab layer from the second side of the slab layer to the first side of the slab layer, and the second electrical contact is coupled to the second dielectric portion by passing through the slab layer from the second side of the slab layer to the first side of the slab layer.

[0011] In some embodiments, the first dielectric portion and the second dielectric portion are composed of one of strontium titanate (STO), barium strontium titanate (BST), hafnium oxide, zirconium oxide, titanium oxide, graphene oxide, tantalum oxide, lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), or strontium barium niobate (SBN).

[0012] In some embodiments, the first material is one of barium titanate (BTO), barium strontium titanate (BST), lithium niobate, lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), aluminum oxide, aluminum nitride, or strontium barium niobate (SBN).

[0013] The present invention content aims to provide a brief overview of some of the topics described in this document. Therefore, it should be recognized that the above features are merely examples and should not be construed as narrowing the scope or spirit of the topics described herein in any way. Other features, aspects, and advantages of the topics described herein will become apparent from the following detailed description, drawings, and claims. Brief Description of the Drawings

[0014] To better understand the various embodiments described, reference should be made to the following detailed description in conjunction with the following drawings, in which like reference numerals refer to corresponding parts throughout the figures.

[0015] Figure 1 is a simplified schematic diagram illustrating an optical switch according to some embodiments;

[0016] Figure 2 is a simplified schematic cross-sectional view illustrating a waveguide structure including high-κ electrodes placed opposite a waveguide ridge according to some embodiments;

[0017] Figure 3 is a simplified schematic cross - sectional view illustrating a waveguide structure according to some embodiments that includes a high - κ electrode placed opposite a waveguide ridge and having a through - lead;

[0018] Figure 4 is a simplified schematic cross - sectional view illustrating a waveguide structure according to some embodiments that includes a high - κ electrode placed on the same side as a waveguide ridge;

[0019] Figure 5 is a simplified schematic cross - sectional view illustrating a waveguide structure according to some embodiments that includes a high - κ electrode and exhibits a sandwich structure;

[0020] Figure 6 is a simplified schematic cross - sectional view illustrating a vertical waveguide structure according to some embodiments that includes a high - κ material;

[0021] Figure 7 is a simplified schematic cross - sectional view illustrating a waveguide structure according to some embodiments that has a dielectric portion aligned with the waveguide structure;

[0022] Figure 8 is a simplified schematic cross - sectional view illustrating a waveguide structure according to some embodiments that has a dielectric portion presenting a ridge profile;

[0023] Figure 9 is a simplified schematic top - view illustrating a waveguide structure according to some embodiments;

[0024] Figure 10 is an illustration of a user interacting with a hybrid quantum computing device interface according to some embodiments; and

[0025] Figure 11 is a simplified schematic cross - sectional view illustrating a waveguide structure according to some embodiments that shows the direction of an induced electric field.

[0026] While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and their detailed description are not intended to be limited to the particular form disclosed, but rather, the intention is to cover all modifications, equivalents, and alternative forms falling within the spirit and scope of the subject matter as defined by the appended claims. Detailed Description

[0027] Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. It will be apparent, however, to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0028] For purposes of explanation, the foregoing description has been presented with reference to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to best explain the principles of the claims and their practical application to thereby enable others skilled in the art to best utilize the embodiments with various modifications as are suited to the particular use contemplated.

[0029] Embodiments of the present invention relate to optical systems. More particularly, embodiments of the present invention use high dielectric constant materials (i.e., high-κ materials) in optical modulators and switches to reduce power consumption during operation. Note that, as used herein, "high dielectric constant material" is intended to indicate a material having a high dielectric permittivity compared to other materials within the operating components of an optical modulator or switch, and in particular compared to the materials used to construct waveguides. By way of example only, embodiments of the present invention are provided in the context of an integrated optical system including active optical devices, but the present invention is not limited to this example and has broad applicability to various optical and optoelectronic systems.

[0030] According to some embodiments, the active photonic devices described herein utilize electro-optic effects such as free-carrier-induced refractive index changes in semiconductors, the Pockels effect, and / or the DC Kerr effect to effect modulation and / or switching of optical signals. Thus, embodiments of the present invention are applicable to modulators in which transmitted light is modulated ON or OFF, or in which light is modulated by a fractional change in transmission percentage, and optical switches in which transmitted light is output onto a first output (e.g., waveguide) or a second output (e.g., waveguide), or an optical switch having more than two outputs and more than one input. Thus, embodiments of the present invention are applicable to a variety of designs, including M(input) x N(output) systems that utilize the methods, devices, and techniques discussed herein.

[0031] Figure 1 is a simplified schematic diagram illustrating an optical switch according to an embodiment of the present invention. Refer to Figure 1, the switch 100 includes two input terminals: input terminal 1 and input terminal 2, and two output terminals: output terminal 1 and output terminal 2. As an example, the input and output terminals of the switch 100 can be implemented as optical waveguides operable to support single-mode or multi-mode light beams. As an example, the switch 100 can be implemented as a Mach-Zehnder interferometer integrated with a set of 50 / 50 beam splitters 105 and 107, respectively. As shown in Figure 1 , the input terminal 1 and the input terminal 2 are optically coupled to a first 50 / 50 beam splitter 105 (also referred to as a directional coupler), which receives light from either the input terminal 1 or the input terminal 2 and, through evanescent coupling in the 50 / 50 beam splitter, directs 50% of the input light from the input terminal 1 into the waveguide 110 and 50% of the input light from the input terminal 1 into the waveguide 112. At the same time, the first 50 / 50 beam splitter 105 directs 50% of the input light from the input terminal 2 into the waveguide 110 and 50% of the input light from the input terminal 2 into the waveguide 112. Considering only the input light from the input terminal 1, this input light is evenly split between the waveguides 110 and 112.

[0032] The Mach-Zehnder interferometer 120 includes a phase adjustment section 122. A voltage V0 can be applied to the waveguides in the phase adjustment section 122 such that it can have a controllably varying refractive index in the phase adjustment section 122. Since the light in the waveguides 110 and 112 still has a well-defined phase relationship after propagating through the first 50 / 50 beam splitter 105 (e.g., they can be in-phase, 180° out-of-phase, etc.), the phase adjustment in the phase adjustment section 122 can introduce a predetermined phase difference between the light propagating in the waveguides 130 and 132. As is clear to those skilled in the art, the phase relationship between the light propagating in the waveguides 130 and 132 can cause the output light to appear at the output terminal 1 (e.g., the light beams are in-phase) or the output terminal 2 (e.g., the light beams are out-of-phase), thus providing a switching function, because depending on the voltage V0 applied at the phase adjustment section 122, the light is directed to the output terminal 1 or the output terminal 2. Although a single active arm is illustrated in Figure 1 , it should be recognized that both arms of the Mach-Zehnder interferometer can include a phase adjustment section.

[0033] As Figure 1 shown, compared with all-optical switching technology, electro-optical switching technology utilizes the application of an electrical bias (e.g., Figure 1 V0 in

[0034] ) on the active region of the switch to produce optical changes. The electric field and / or current generated by the application of this voltage bias cause one or more optical properties (such as refractive index or absorbance) of the active region to change. Figure 1A Mach-Zehnder interferometer implementation is illustrated, but embodiments of the present invention are not limited to this particular switch architecture, and other phase adjustment devices are included within the scope of the present invention, including ring resonator designs, Mach-Zehnder modulators, generalized Mach-Zehnder modulators, and the like. Those of ordinary skill in the art will recognize many variations, modifications, and alternative forms.

[0035] In some embodiments, the optical phase shifter devices described herein can be used within a quantum computing system, such as Figure 10 the hybrid quantum computing system shown. Alternatively, these optical phase shifter devices can be used in other types of optical systems. For example, other computing, communication, and / or technology systems can utilize photon phase shifters to direct optical signals (e.g., single photon or continuous wave (CW) optical signals) within the system or network, and in various embodiments, the phase shifter architectures described herein can be used within these systems.

[0036] Figures 2 - 8 – Cross-section of the photon phase shifter

[0037] Figures 2 - 8 are simplified cross-sectional views illustrating various architectures for a photon phase shifter according to various embodiments. Note that Figures 2 - 8 the architectures shown are schematic diagrams and are not necessarily drawn to scale. Although Figures 2 - 8 the architectures shown differ in several important design features, they also share some common features. For example, as described in more detail below, Figures 2 - 8 each of them shows two electrical contacts, and each electrical contact includes leads (230, 330, 430, 530, 630, 730, and 830, and 232, 332, 432, 532, 632, 732, and 832) connected to dielectric electrodes (240, 340, 440, 540, 640, 740, and 840, and 242, 342, 442, 542, 642, 742, and 842). In some embodiments, the leads can be made of metal or alternatively of semiconductor material.

[0038] The dielectric electrodes are configured to extend in a position close to the optical mode in the waveguide, and the photon phase shifter is configured such that a controllable voltage difference can be introduced across the two dielectric electrodes to change the cumulative phase of the photon mode propagating through the waveguide. For example, the dielectric electrodes can be coupled via the leads to a voltage source that applies a controllable voltage difference.

[0039] Importantly, the dielectric electrodes can be made of a high-κ material having a large dielectric constant such that the dielectric electrodes have a larger dielectric constant than the material of the waveguide and / or slab layer. As used herein, κ is used to represent the dielectric constant, which refers to the real component of the relative permittivity, κ = Re(εr ) = Re(ε / ε0), where ε r is the complex-valued relative permittivity, ε is the absolute permittivity of the material, and ε0 is the permittivity of free space. It should be noted that, for clarity, the imaginary component of ε r is related to the conductivity of the material, while the real component κ is related to the dielectric susceptibility of the material.

[0040] Compared to an (AC) voltage, in the presence of a direct current (DC) voltage, the dielectric constant of the material may have a different value, and the dielectric constant of the material under an AC voltage may be a function of frequency κ(ω). Thus, in some embodiments, when selecting a material for the dielectric electrode, the planar layer, and / or the ridge waveguide, the dielectric constant of the material at the operating frequency of the photon phase shifter may be considered.

[0041] The dielectric electrode may be formed of a material having a higher dielectric constant than the first material of the planar layer along the direction separating the first dielectric portion and the second dielectric portion (e.g., Figures 2 - 5 and Figures 7 - 8 the x-direction in Figure 6 or the y-direction in

[0042]

[0043] where the components ε xx , ε xy , etc. represent the respective components of the permittivity tensor. In some embodiments, the materials of the first dielectric electrode and the second dielectric electrode may be selected such that the diagonal components of the permittivity tensor along the direction separating the dielectric electrodes are greater than the corresponding diagonal components of the permittivity tensor of the material of the planar layer and / or the waveguide structure.

[0044]

[0045]

[0046] Table 1 - χ of various materials (3) , refractive index, and dielectric constant values

[0047] Table 1 illustrates the χ (3) , refractive index, and dielectric constant values of various materials. As shown in Table 1, in some embodiments, STO has an extremely high dielectric constant for temperatures below 10K, such that STO can be an ideal material for the dielectric electrode, while BTO can be used for the planar layer and / or the ridge portion of the waveguide.

[0048] As shown in the figure, Figures 2 - 8The architectures shown in each of [the figures] illustrate a photonic device including a first cladding layer and a second cladding layer. For example, the regions labeled 210, 310, 410, 510, 610, 710, and 810 represent the first cladding layer on one side of the waveguide, while the regions labeled 212, 312, 412, 512, 612, 712, and 812 represent the second cladding layer on the other side of the waveguide. Note that the terms "first" and "second" are only used to distinguish the two cladding layers. For example, the term "first cladding layer" can refer to the cladding layer on either side of the waveguide. In some embodiments, the refractive indices of the first cladding layer and the second cladding layer can be lower than the refractive index of the waveguide structure.

[0049] Figures 2 - 8 Also shown are a first electrical contact and a second electrical contact. The first electrical contact includes a first lead (230, 330, 430, 530, 630, 730, and 830) coupled to a first dielectric portion (240, 340, 440, 540, 640, 740, and 840), and the second electrical contact includes a second lead (232, 332, 432, 532, 632, 732, and 842) coupled to a second dielectric portion (242, 342, 442, 542, 642, 742, and 842). The first and second leads can be made of a conductive material such as metal, or alternatively they can be made of a semiconductor material. In various embodiments, the first dielectric portion and the second dielectric portion are made of one or more of strontium titanate (STO), barium titanate (BTO), barium strontium titanate (BST), hafnium oxide, lithium niobate, zirconium oxide, titanium oxide, graphene oxide, tantalum oxide, lead zirconate titanate (PZT), lanthanum lead zirconate titanate (PLZT), strontium barium niobate (SBN), alumina, aluminum oxide, or a doped variant or solid solution thereof.

[0050] Figures 2 - 8 Illustrated is a waveguide structure including slab layers (220, 320, 420, and 520, 651, 754, and 851) that contain a first material, where the slab layers are coupled to the first dielectric portion of the first electrical contact and the second dielectric portion of the second electrical contact. In some embodiments, the waveguide structure further includes ridge portions (251, 351, 451, and 551) made of the first material (or a different material, such as silicon nitride or any other material) and coupled to the slab layers, where the ridge portions are disposed between the first electrical contact and the second electrical contact. In various embodiments, the first material is one of strontium titanate (STO), barium titanate (BTO), barium strontium titanate (BST), hafnium oxide, lithium niobate, zirconium oxide, titanium oxide, graphene oxide, tantalum oxide, lead zirconate titanate (PZT), lanthanum lead zirconate titanate (PLZT), strontium barium niobate (SBN), alumina, aluminum oxide, or a doped variant or solid solution thereof.

[0051] In some embodiments, the second material that forms the first dielectric portion and the second dielectric portion can be selected based on the first material that forms the slab layer and / or the waveguide structure. For example, the second material can be selected such that it has a larger dielectric constant than the dielectric constant of the first material. As an example, if the first material is BTO, then the second material can be selected as STO, which has a larger dielectric constant than BTO at the cryogenic temperatures (e.g., 4K) at which the photonic device is intended to operate. Advantageously, for a given acceptable level of loss from the waveguide into the electrodes, the large dielectric constant of the dielectric electrodes can enable the dielectric electrodes to be placed closer to the waveguide compared to metal electrodes. For example, the high conductivity of metal electrodes will result in a greater degree of photon absorption (i.e., loss) from the waveguide than that of dielectric electrodes at the same spacing from the waveguide. Thus, for a given loss tolerance, the dielectric electrodes can be placed closer to the waveguide than metal electrodes. The high dielectric constant of the dielectric electrodes corresponds to a high polarizability of the dielectric material, which in turn leads to an energy-saving control mechanism to regulate the electric field within the waveguide structure.

[0052] In some embodiments, the materials for the dielectric electrodes and the waveguide structure can be selected based on their effective dielectric constants. For example, while the dielectric constant of a material (or the dielectric tensor of an anisotropic material) is an inherent material property, the effective dielectric constant of a structure not only scales with its dielectric constant but also depends on the shape and size of the structure. In these embodiments, the materials for the first dielectric portion and the second dielectric portion can be selected such that the effective dielectric constants of the first dielectric portion and the second dielectric portion are greater than the effective dielectric constant of the waveguide structure.

[0053] In some embodiments, cryogenic devices such as Figure 10 the cryostat 1113 shown in can be configured to maintain the first electrical contact, the second electrical contact, and the waveguide structure at cryogenic temperatures, e.g., at or below 77 Kelvin.

[0054] In some embodiments, the first electrical contact and the second electrical contact are configured to generate an electric field in the waveguide structure along one or more directions (e.g., along the x direction), and the waveguide structure is characterized in that the electro-optic coefficient (e.g., χ (2) Pockels coefficient, or χ (3) Kerr coefficient) has a non-zero value aligned along the direction of the electric field. For example, leads can be coupled to a voltage source that applies a controllable (e.g., programmable) voltage difference, thereby generating an electric field in the waveguide structure, as Figure 10 shown in. Additionally or alternatively, the guided modes supported by the waveguide structure can have a polarization direction aligned with the x direction.

[0055] In some embodiments, the first dielectric portion and the second dielectric portion are configured to be coplanar with the slab layer and deployed adjacent to a first side of the slab layer as a second layer. For example, the first dielectric portion and the second dielectric portion can be grown (e.g., using epitaxy or another method such as metalorganic chemical vapor deposition, molecular beam epitaxy, physical vapor deposition, sol-gel, etc.) onto the first side of the slab layer such that the first dielectric layer and the second dielectric layer are directly coupled to the slab layer. Alternatively, in some embodiments, an intermediate layer can be deployed between the slab layer and the first dielectric layer and the second dielectric layer such that the slab layer is indirectly coupled to the first dielectric layer and the second dielectric layer. In some embodiments, the intermediate layer can be composed of an oxide material.

[0056] The first dielectric portion and the second dielectric portion can be separated by a gap region (e.g., gap region 243 or 343). In some embodiments, the gap region may have been etched away and can be filled with a cladding material. In some embodiments, both the first dielectric portion and the second dielectric portion can be grown as a single second layer over the slab layer and then an area can be etched away to separate the first dielectric portion and the second dielectric portion. The etched area can then be filled with a cladding material. Alternatively, the etched area can be left empty (i.e., can be filled with air or a vacuum).

[0057] In some embodiments, the dielectric constants of the first dielectric portion and the second dielectric portion are greater than the dielectric constant of a first material in a direction separating the first dielectric portion and the second dielectric portion. At a first temperature greater than 1 mK, less than 77 K, less than 150 K, and / or within another temperature range, the dielectric constants of the first dielectric portion and the second dielectric portion can be greater than the dielectric constant of the waveguide structure. In some embodiments, the first material is a transparent material having a refractive index greater than the refractive indices of the first cladding layer and the second cladding layer. In some embodiments, the ratio of the dielectric constant of the first dielectric portion and the second dielectric portion to the dielectric constant of the first material is 2 or greater.

[0058] The following paragraphs describe various design features that are different between the architectures shown in Figures 2 - 8 various architectures.

[0059] Figure 2 An architecture is illustrated in which a ridge portion (251) of the waveguide structure is deployed at the bottom of the slab layer and extends into the first cladding layer (210). As Figure 2 shown, the combination of the ridge portion and the slab layer has a first thickness (262) that is greater than a second thickness (260) of the slab layer alone, and the excess of the first thickness relative to the second thickness extends into the cladding layer (210) on the bottom side of the slab layer. As Figure 2As shown, a first dielectric portion (240) and a second dielectric portion (242) are coupled to a flat plate layer (220) on a top side of the flat plate layer opposite a bottom side. In addition, a first electrical contact (230) and a second electrical contact (232) are disposed on the top side of the flat plate layer (220). It should be noted that the terms "top" and "bottom" are used for clarity with reference to the perspective view shown in the figure and do not necessarily refer to any particular orientation with respect to the entire device.

[0060] Figure 3 Illustrated is an architecture in which a ridge portion (351) of a waveguide structure is disposed on a top side of a flat plate layer and extends into a first cladding layer (312), and a first dielectric portion and a second dielectric portion are coupled to the flat plate layer on a bottom side of the flat plate layer opposite the top side. As shown, a combination of the ridge portion and the flat plate layer has a first thickness (362) greater than a second thickness (360) of the flat plate layer alone (320), and an excess of the first thickness over the second thickness extends into the first cladding layer (312) on the top side of the flat plate layer (320). As Figure 3 As shown, a first dielectric portion (340) and a second dielectric portion (342) are coupled to a flat plate layer (320) on a bottom side of the flat plate layer opposite the top side. In addition, a first electrical contact (330) is coupled to the first dielectric portion (340) by passing through the flat plate layer (320) from the top side of the flat plate layer to the bottom side, and a second electrical contact (332) is coupled to the second dielectric portion (342) by passing through the flat plate layer (320) from the top side of the flat plate layer to the bottom side.

[0061] Figure 4 Illustrated is an architecture in which a combination of a ridge portion (451) of a waveguide structure and a flat plate layer has a first thickness (462) greater than a second thickness (460) of the flat plate layer (420) and an excess of the first thickness over the second thickness extends into the first cladding layer (412) on the top side of the flat plate layer. As Figure 4 As shown, a first dielectric portion (440) and a second dielectric portion (442) are coupled to a first material (420) on the top side of the flat plate layer. In addition, the first dielectric portion (440) and the second dielectric portion (442) are adjacent to a ridge portion (451) of the waveguide structure.

[0062] Figure 5Illustrates an architecture in which a waveguide structure includes a first strip waveguide portion (554) and a second strip waveguide portion (556), where the first strip waveguide portion and the second strip waveguide portion are made of a second material and a third material respectively, and where a slab layer (520) is disposed between the first strip waveguide portion (554) and the second strip waveguide portion (556). The first strip waveguide portion and the second strip waveguide portion may be made of the same or different materials. For example, they may each be made of silicon nitride (Si3N4), silicon dioxide (SiO2), aluminum oxide (Al2O3), or other similar materials respectively.

[0063] Figure 6 Illustrates a vertical waveguide architecture in which a first dielectric portion (642) is coupled to a slab layer (651) on the top side of the slab layer and a second dielectric portion (640) is coupled to the slab layer (651) on the bottom side opposite to the top side of the slab layer. In other words, the first dielectric portion and the second dielectric portion are coupled to the top side and the bottom side of the waveguide structure such that the induced electric field within the waveguide structure is oriented along the y direction.

[0064] Figure 7 Illustrates a waveguide architecture in which each of a first dielectric portion (740) and a second dielectric portion (742) is disposed in a straight line with a waveguide structure (754). In other words, each of the first dielectric portion and the second dielectric portion is disposed with the waveguide structure in a single layer having a single width.

[0065] Figure 8 Illustrates a waveguide architecture in which a first dielectric portion (840) and a second dielectric portion (842) share a ridge profile with a waveguide structure (851), where the ridge profile extends into a first cladding layer (812). For example, the first dielectric portion (840) may include a ridge portion (844) whose thickness (862) is greater than the thickness (860) of the rest of the first dielectric portion, and the second dielectric portion (842) may include a ridge portion (846) whose thickness (862) is greater than the thickness (860) of the rest of the second dielectric portion. In addition, the ridge portions of the first dielectric portion and the second dielectric portion may exhibit the same thickness as the waveguide structure (851).

[0066] Figure 9 – Top view of the photon phase shifter

[0067] Figure 9 Is a top view of a photon phase shifter architecture according to some embodiments. As shown, the phase shifter may include a first lead (930) and a second lead (932), a first dielectric portion (940) and a second dielectric portion (942), a slab layer (920), and a ridge portion (951) of a waveguide structure.

[0068] Figure 10 – Hybrid quantum computing system

[0069] Figure 10 is a simplified system diagram illustrating the incorporation of an electro-optic switch with a cryostat into a hybrid quantum computing system according to some embodiments. For operation at cryogenic temperatures (e.g., liquid helium temperature), embodiments of the present invention integrate the electro-optic switch discussed herein into a system that includes a cooling system. Thus, embodiments of the present invention provide an optical phase shifter that can be used in a hybrid computing system, e.g., as shown in Figure 8 FIG. The hybrid computing system 1101 includes a user interface device 1103 communicatively coupled to a hybrid quantum computing (QC) subsystem 1105. The user interface device 1103 can be any type of user interface device, e.g., a terminal including a display, keyboard, mouse, touch screen, etc. Additionally, the user interface device itself can be a computer such as a personal computer (PC), laptop, tablet computer, etc. In some embodiments, the user interface device 1103 provides an interface through which a user can interact with the hybrid QC subsystem 1105. For example, the user interface device 1103 can run software such as a text editor, interactive development environment (IDE), command prompt, graphical user interface, etc., such that the user can program the QC subsystem or otherwise interact with it to run one or more quantum algorithms. In other embodiments, the QC subsystem 1105 can be pre-programmed, and the user interface device 1103 can simply be an interface through which a user can initiate quantum computing, monitor the process, and receive results from the hybrid QC subsystem 1105. The hybrid QC subsystem 1105 also includes a classical computing system 1107 coupled to one or more quantum computing chips 1109. In some examples, the classical computing system 1107 and the quantum computing chips 1109 can be coupled to other electronic components 1111, e.g., pulsed pump lasers, microwave oscillators, power supplies, networking hardware, etc.

[0070] In some embodiments that utilize cryogenic operation, the quantum computing system 1109 can be housed within a cryostat (e.g., cryostat 1113). In some embodiments, the quantum computing chip 1109 can include one or more constituent chips, e.g., a hybrid electronic chip 1115 and an integrated photonics chip 1117. Signals can be routed on-chip and off-chip in a variety of ways, e.g., via optical interconnections 1119 and via other electronic interconnections 1121.

[0071] Figure 11 – Induced Electric Field in Photonic Phase Shifter

[0072] Figure 11 illustrates according to some embodiments of Figure 2A simplified schematic view of a cross-section of the waveguide structure shown in [description], where the direction of the induced electric field is shown by arrows. As shown, the small arrows show the direction of the induced electric field, which generally points along the positive x-direction through the dielectric portion of the device. As shown, the electric field bends in a convex manner both above and below the dielectric portion. In addition, the large arrow (1150) pointing in the positive x-direction illustrates the polarization direction of the optical mode that can travel through the slab layer and the waveguide.

[0073] In some embodiments, the first dielectric portion, the second dielectric portion, and the waveguide structure are deployed within a single layer having a first thickness, and the waveguide structure is deployed between the first dielectric portion and the second dielectric portion. For example, see Figure 7 .

[0074] In some embodiments, the first dielectric portion and the second dielectric portion each include a respective ridge structure, the first thickness of which is greater than the second thickness of the slab structures of the first dielectric portion and the second dielectric portion. The first thickness is the same as the thickness of the waveguide structure. In these embodiments, the waveguide structure is deployed between the first dielectric portion and the second dielectric portion and is coupled to the ridge structures of the first dielectric portion and the second dielectric portion. For example, see Figure 8 .

[0075] It should also be understood that the examples and embodiments described herein are for illustrative purposes only, and various modifications or changes thereto will be suggested to those skilled in the art and will be included within the spirit and scope of this application and the scope of the appended claims.

Claims

1. An electro - optical device, comprising: A first cladding layer; A first electrical contact, comprising a first lead and a first dielectric electrode, wherein the first lead is coupled to the first dielectric electrode; A second electrical contact, comprising a second lead and a second dielectric electrode, wherein the second lead is coupled to the second dielectric electrode, and wherein the first dielectric electrode and the second dielectric electrode are separated by a gap region; A waveguide structure, comprising a slab layer made of barium titanate, wherein the slab layer is coupled to the first dielectric electrode of the first electrical contact and the second dielectric electrode of the second electrical contact; A ridge portion coupled to the slab layer, wherein the ridge portion is disposed between the first electrical contact and the second electrical contact; And A second cladding layer, Wherein the dielectric constants of the first dielectric electrode and the second dielectric electrode in a first direction are greater than the dielectric constant of barium titanate in the first direction, wherein the first direction includes the direction separating the first dielectric electrode from the second dielectric electrode, and wherein the first direction is parallel to the slab layer; and Wherein the first dielectric electrode and the second dielectric electrode are configured to generate an electric field in the waveguide structure along the first direction.

2. The device according to claim 1, Wherein the ridge portion is disposed on a first side of the slab layer and extends into the first cladding layer, and Wherein the first dielectric electrode and the second dielectric electrode are coupled to the slab layer on a second side of the slab layer opposite to the first side.

3. The device according to claim 1, wherein the slab layer is made of a material different from that of the ridge portion.

4. An electro - optical device, comprising: A first cladding layer; A first electrical contact, comprising a first lead and a first dielectric electrode, wherein the first lead is coupled to the first dielectric electrode; A second electrical contact, comprising a second lead and a second dielectric electrode, wherein the second lead is coupled to the second dielectric electrode; A waveguide structure, comprising a slab layer made of a first material, wherein the slab layer is coupled to the first dielectric electrode of the first electrical contact and the second dielectric electrode of the second electrical contact; And A second cladding layer, Wherein the dielectric constants of the first dielectric electrode and the second dielectric electrode in a first direction are greater than the dielectric constant of the first material in the first direction, wherein the first direction is the direction separating the first dielectric electrode from the second dielectric electrode and parallel to the slab layer, and Wherein the first dielectric electrode and the second dielectric electrode are configured to generate an electric field in the waveguide structure along the first direction.

5. The device according to claim 4, Wherein the waveguide structure further comprises a first ridge portion coupled to the slab layer, wherein the first ridge portion is disposed between the first electrical contact and the second electrical contact.

6. The device according to claim 5, Wherein the slab layer is made of barium titanate, and Wherein the first ridge portion is made of silicon nitride.

7. The device according to claim 5, Wherein the first ridge portion is made of the first material.

8. The device according to claim 5, Wherein the first ridge portion is disposed on a first side of the slab layer and extends into the first cladding layer, and Wherein the first dielectric electrode and the second dielectric electrode are coupled to the slab layer on the first side of the slab layer.

9. The device according to claim 5, Wherein the ridge portion is disposed on a first side of the slab layer and extends into the first cladding layer, Wherein the first dielectric electrode and the second dielectric electrode are coupled to the slab layer on a second side of the slab layer opposite to the first side.

10. The device according to claim 9, wherein the first electrical contact member and the second electrical contact member are disposed on the second side of the flat plate layer.

11. The device according to claim 9, wherein the first electrical contact member is coupled to the first dielectric electrode by passing through the flat plate layer from the second side of the flat plate layer to the first side of the flat plate layer, and wherein the second electrical contact member is coupled to the second dielectric electrode by passing through the flat plate layer from the second side of the flat plate layer to the first side of the flat plate layer.

12. The device according to claim 4, wherein the first dielectric electrode and the second dielectric electrode are made of strontium titanate.

13. The device according to claim 4, wherein the waveguide structure further includes a first strip waveguide portion and a second strip waveguide portion, wherein the first strip waveguide portion and the second strip waveguide portion are made of a second material and a third material respectively, and wherein the flat plate layer is disposed between the first strip waveguide portion and the second strip waveguide portion.

14. The device according to claim 13, wherein the second material and the third material are silicon nitride.

15. The device according to claim 4, wherein the first dielectric electrode and the second dielectric electrode are included in a second layer coplanar with the flat plate layer and are disposed adjacent to the first side of the flat plate layer.

16. The device according to claim 4, wherein the first dielectric electrode and the second dielectric electrode are separated by a gap region.

17. The device according to claim 4, wherein the refractive index of the first material is greater than the refractive indices of the first cladding layer and the second cladding layer.

18. The device according to claim 4, wherein the ratio of the dielectric constants of the first dielectric electrode and the second dielectric electrode to the dielectric constant of the first material in the first direction is 2 or greater.

19. The device according to claim 4, wherein the first dielectric electrode is coupled to the flat plate layer on the first side of the flat plate layer, and wherein the second dielectric electrode is coupled to the flat plate layer on the second side of the flat plate layer opposite to the first side.

20. The device according to claim 4, wherein the first dielectric electrode and the second dielectric electrode are made of one of the following: barium strontium titanate; hafnium oxide; zirconium oxide; titanium oxide; graphene oxide; tantalum oxide; lead zirconate titanate; lead lanthanum zirconate titanate; or barium strontium niobate.

21. The device according to claim 4, wherein the flat plate layer is made of barium titanate.

22. The device according to claim 4, wherein the flat plate layer is made of one of the following: barium strontium titanate; lithium niobate; lead zirconate titanate; lead lanthanum zirconate titanate; aluminum oxide; aluminum nitrite; or barium strontium niobate.

23. The device according to claim 4, wherein the waveguide structure is characterized in that the electro-optic coefficient has a non-zero value aligned along the first direction.

24. The device according to claim 4, further comprising: a cryogenic device configured to maintain the first electrical contact member, the second electrical contact member, and the waveguide structure at 77 Kelvin or below.

25. The device according to claim 4, Among them, at a first temperature greater than 1 mK, the dielectric constants of the first dielectric electrode and the second dielectric electrode in the first direction are greater than the dielectric constant of the first material.

26. The device according to claim 4, Among them, at a first temperature greater than 1 mK and less than 77 K, the dielectric constants of the first dielectric electrode and the second dielectric electrode in the first direction are greater than the dielectric constant of the first material.

27. The device according to claim 4, wherein the first lead and the second lead are made of metal.

28. The device according to claim 4, wherein the first lead and the second lead are made of semiconductor material.

29. The device according to claim 4, wherein the first dielectric electrode, the second dielectric electrode, and the waveguide structure are disposed within a single layer having a first thickness, and wherein the waveguide structure is disposed between the first dielectric electrode and the second dielectric electrode.

30. The device according to claim 4, wherein the first dielectric electrode and the second dielectric electrode each include a respective ridge structure having a first thickness greater than a second thickness of a planar structure of the first dielectric electrode and the second dielectric electrode, wherein the waveguide structure is disposed between the first dielectric electrode and the second dielectric electrode and is coupled to the ridge structures of the first dielectric electrode and the second dielectric electrode, and wherein the waveguide structure has a first thickness.

31. An optical switch, comprising: at least one input port; at least one output port; a Mach-Zehnder interferometer coupled to a beam splitter, wherein the Mach-Zehnder interferometer includes a first arm and a second arm; a photon phase shifter included within the first arm of the Mach-Zehnder interferometer, the photon phase shifter comprising: a first cladding layer; a first electrical contact including a first lead coupled to a first dielectric electrode; a second electrical contact including a second lead coupled to a second dielectric electrode; a waveguide structure including a planar layer made of a first material, wherein the planar layer is coupled to the first dielectric electrode of the first electrical contact and the second dielectric electrode of the second electrical contact; and a second cladding layer, wherein the dielectric constant of the first dielectric electrode and the second dielectric electrode in a first direction is greater than the dielectric constant of the first material in the first direction, where the first direction is a direction separating the first dielectric electrode from the second dielectric electrode and parallel to the planar layer, and wherein the first dielectric electrode and the second dielectric electrode are configured to generate an electric field in the waveguide structure along the first direction.

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