Deep etch electro-optic waveguide modulator with non-constant waveguide width

Abstract

The invention relates to a deep etch electro-optic waveguide modulator with a non-constant waveguide width. In some implementations, an electro-optical waveguide modulator includes a deep etched waveguide. A first cladding is disposed on a top surface of the deep etched waveguide. A second cladding is disposed on a bottom surface of the deep etched waveguide. The deep etch waveguide has a length extending in the first direction and a width extending in the second direction. The width of the deep etched waveguide is non-constant along at least a portion of the length of the deep etched waveguide. For example, a difference between a maximum width of the deep etch waveguide along the at least a portion of the length of the deep etch waveguide and a minimum width of the deep etch waveguide satisfies a width difference threshold equal to 10% of the maximum width.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Patent Application No. 63 / 588,512 filed on October 6, 2023 and entitled “METHOD FOR REDUCING ACOUSTO-OPTIC DISTORTION OF ELECTRO-OPTIC MODULATOR FREQUENCY RESPONSE.” The disclosure of the prior application is considered part of and incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to electro-optic waveguide modulators and to electro-optic waveguide modulators having a non-constant waveguide width. Background Art

[0004] In a deep etched waveguide, the etch depth extends from the upper cladding through the waveguide into the lower cladding region. When the waveguide contains a material comprising an unconstrained linear electro-optic crystal, application of an electric field to the waveguide (e.g., to enable electro-optic modulation of the waveguide) can induce mechanical deformation of the material (e.g., as a result of the inverse piezoelectric effect). This material strain can cause acoustic waves (e.g., generated by the exposed depletion field of the waveguide and then confined by the sidewalls of the waveguide), which is often referred to as the acousto-optic effect. Summary of the invention

[0005] In some implementations, an electro-optic waveguide modulator includes: a deeply etched waveguide; a first cladding disposed on a top surface of the deeply etched waveguide; and a second cladding disposed on a bottom surface of the deeply etched waveguide, wherein: the deeply etched waveguide has a length extending in a first direction and a width extending in a second direction, and the width of the deeply etched waveguide is non-constant along at least a portion of the length of the deep etched waveguide.

[0006] In some implementations, an electro-optic waveguide modulator includes: a deeply etched waveguide, wherein: the deeply etched waveguide has a length extending in a first direction and a width extending in a second direction, and a difference between a maximum width of the deep etched waveguide and a minimum width of the deep etched waveguide along at least a portion of the length of the deep etched waveguide satisfies a width difference threshold, which is equal to 10% of the maximum width.

[0007] In some implementations, an electro-optic device includes an electro-optic waveguide modulator having a deep etched waveguide, wherein the deep etched waveguide has a length extending in a first direction and a width extending in a second direction, and the width of the deep etched waveguide is non-constant along at least a portion of the length of the deep etched waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a diagram of an example implementation described herein.

[0009] Figure 2 is a diagram of an example implementation described herein.

[0010] Figure 3 is an illustration of example graphics related to example implementations described herein. DETAILED DESCRIPTION

[0011] The following detailed description of example implementations refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0012] An electro-optic waveguide modulator may contain a waveguide (e.g., a waveguide comprising a III-V semiconductor material; an electro-optic material, such as lithium niobate (LiNbO3) or silicon (Si); and / or another material). In many cases, such as when the waveguide is deeply etched, an acousto-optic effect (e.g., an acousto-optic effect in a waveguide of an electro-optic waveguide modulator) may cause a resonance in the frequency response of the electro-optic waveguide modulator. This may be referred to as an acousto-optic resonance. For example, an acousto-optic effect in a deeply etched waveguide (e.g., comprising indium phosphide (InP) and / or gallium arsenide (GaAs)) of an electro-optic waveguide modulator may cause an acousto-optic resonance when half of the wavelength of the acoustic wave associated with the acousto-optic effect (e.g., the wavelength of the acoustic wave associated with the frequency of the acousto-optic effect) is equal to the width of the waveguide. This acousto-optic resonance may be difficult to identify and difficult to resolve, which affects the performance of the electro-optic waveguide modulator.

[0013] Some implementations described herein include an electro-optic waveguide modulator that includes a waveguide having a non-constant width (e.g., a deeply etched waveguide). For example, a first width of the waveguide at a first point (e.g., along the length of the waveguide) can be smaller than a second width at a second point (e.g., along the length of the waveguide). To enable the waveguide to have a non-constant width, the waveguide can include at least one sidewall that is tapered, curved, corrugated, and / or roughened.

[0014] The non-constant width of the waveguide enables acousto-optic resonance (e.g., due to the acousto-optic effect) in the electro-optic waveguide modulator to be minimized. For example, compared to a waveguide with a constant width, the non-constant width enables the amplitude of the acousto-optic resonance (e.g., the difference between the maximum and minimum values) to be reduced and / or the width of the acousto-optic resonance to be distributed over a larger frequency range (e.g., rather than concentrated in a narrow frequency range). This thereby reduces the impact of the acousto-optic resonance on the performance of the electro-optic waveguide modulator.

[0015] Figure 1 is a diagram of an example implementation 100 described herein. Figure 11 shows an angled front view of an electro-optic waveguide modulator 102. The electro-optic waveguide modulator 102 may be included in an electro-optic device such as a Mach Zehnder modulator chip (e.g., supporting frequencies from 1 GHz to 50 GHz) or another type of electro-optic device (e.g., for fiber optic communications). Figure 1 As shown in , the electro-optic waveguide modulator 102 may include a substrate 104 , a waveguide 106 , a first cladding 108 , and / or a second cladding 110 .

[0016] The substrate 104 is a support material on which one or more layers or features of the electro-optic waveguide modulator 102 are grown, fabricated, or otherwise formed. In some implementations, the substrate 104 may contain a material including at least one of indium phosphide (InP), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), and / or another III-V semiconductor material. In practice, the substrate 104 may be a III-V semiconductor substrate, which corresponds to the III-V material included in the electro-optic waveguide modulator 102 (or the waveguide 106 of the electro-optic waveguide modulator 102). Therefore, in some implementations, the electro-optic waveguide modulator 102 may be referred to as a III-V semiconductor electro-optic waveguide modulator. In some implementations, the substrate 104 may contain a material including at least one of indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), gallium phosphide (GaP), and / or another material.

[0017] The waveguide 106 can be disposed on the substrate 104. The waveguide 106 is a structure, channel, or other optical element configured to confine and propagate light within the waveguide 106, as further described herein. In some implementations, the waveguide 106 can contain a material including at least one of InP, GaAs, AlGaAs, another III-V semiconductor material, an electro-optical material (e.g., lithium niobate (LiNbO3), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), and / or gallium phosphide (GaP)), and / or another material. Figure 1 As shown in FIG. , the waveguide has a first direction (eg, parallel to Figure 1 112 extending in a second direction (eg, parallel to the z-axis shown in FIG. Figure 1 The width 114 extends in the x-axis direction (shown in FIG. 1 ) and in a third direction (eg, parallel to Figure 1106 ) along the y-axis shown in FIG. 10 . That is, the first direction, the second direction, and the third direction may be orthogonal to each other. In addition, each of the length 112, the width 114, and the height 116 may be different from each other. Each of the width 114 and the height 116 may extend from 0.5 micrometers (μm) to 4.0 micrometers (μm) (e.g., greater than or equal to 0.5 μm and less than or equal to 4.0 μm). In some implementations, the cross-section of the waveguide 106 (e.g., at a point along the length 112 of the waveguide 106) may be square, rectangular, polygonal, or another type of shape (e.g., circular or having a curved portion).

[0018] The waveguide 106 can be associated with a first cladding 108 and / or a second cladding 110. For example, the first cladding 108 and / or the second cladding 110 can be disposed on respective surfaces of the waveguide 106 (e.g., a top surface and a bottom surface, respectively, such as Figure 1 ) and can be configured to confine light within the waveguide 106 (e.g., when the light propagates within the waveguide, as further described herein). In some implementations, each of the first cladding 108 and the second cladding 110 can contain a material including at least one of InP, GaAs, AlGaAs, another III-V semiconductor material, an electro-optical material (e.g., lithium niobate (LiNbO3), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), and / or gallium phosphide (GaP)), and / or another material, and can have a refractive index less than the refractive index of the waveguide 106 (e.g., to help confine the light within the waveguide 106).

[0019] like Figure 1 As shown in , the second cladding 110 may be disposed on the substrate 104 (e.g., the top surface of the substrate 104), the waveguide 106 may be disposed on the second cladding 110 (e.g., the top surface of the second cladding 110), and the first cladding 108 may be disposed on the waveguide 106 (e.g., the top surface of the waveguide 106). In this manner, the waveguide 106 and at least a portion of the first cladding 108 and the second cladding 110 may form a raised structure on the substrate 104. An etching process (or similar material removal process) may be used to remove a portion of the first cladding 108, the waveguide 106, and the second cladding 110 so that the raised structure is formed. This may be referred to as a "deep etching" process because a portion of each of the first cladding 108, the waveguide 106, and the second cladding 110 is removed, which results in the sidewalls of the waveguide 106 being "exposed" (e.g., no cladding is disposed on the sidewalls). Therefore, the waveguide 106 may be referred to as a "deep etched waveguide".

[0020] In some implementations, the passivation layer ( Figure 11 (not shown) may be disposed on each of the sidewalls of the waveguide 106. The passivation layer may include a material including at least a dielectric such as silicon dioxide (SiO2). The passivation layer may be configured to protect the sidewalls from exposure to air (e.g., to prevent oxidation of the core 118 of the waveguide 106 described herein). The passivation layer may have a thickness that satisfies (e.g., is less than or equal to) a thickness threshold, where the thickness threshold is 0.1 μm. Alternatively, in some implementations, a passivation layer may not be disposed on the sidewalls of the waveguide 106.

[0021] like Figure 1 As further shown in , the waveguide 106 may include a core 118. The core 118 may contain a material including at least InP, GaAs, AlGaAs, another III-V semiconductor material, an electro-optical material (e.g., lithium niobate (LiNbO3), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), and / or gallium phosphide (GaP)), and / or another material, and may include, for example, one or more dopants. In some implementations, the core 118 may include an electro-optical material that is capable of changing one or more optical properties (such as a refractive index) of the core 118 in response to an applied electric field (e.g., to enable electro-optic modulation). The core 118 may be disposed in a central region of the waveguide 106 (reflected by a plurality of electrodes). Figure 1 For example, the central region may extend along at least a portion of the width 114 and at least a portion of the height 116 of the waveguide 106 and may extend along the length 112 of the waveguide 106 from an input end 120 of the waveguide 106 to an output end 122 of the waveguide 106.

[0022] Thus, the waveguide 106 can be configured to receive light at an input end 120 of the waveguide 106, propagate the light from the input end 120 to an output end 122 of the waveguide 106 (e.g., via at least the core 118 of the waveguide 106), and provide light from the output end 122 of the waveguide 106 (e.g., from at least the core 118). In this manner, the waveguide 106 can be configured to propagate light (e.g., via at least the core 118 of the waveguide 106) from the input end 120 to the output end 122 in a first direction (e.g., along the length 112 of the waveguide 106).

[0023] In some implementations, the width 114 of the waveguide 106 can be non-constant along at least a portion of the length 112 of the waveguide 106. For example, Figure 1, the width 114 of the waveguide 106 at the input end 120 of the waveguide 106 can be greater than the width 114 of the waveguide 106 at the output end 122 of the waveguide 106 (e.g., because the sidewalls of the waveguide 106 taper “inwardly” from the input end 120 to the output end 122). The width 114 of the waveguide 106 can be non-constant when, for example, a difference between a maximum width 114 of the waveguide 106 and a minimum width 114 of the waveguide 106 (e.g., along at least a portion of the length 112 of the waveguide 106) satisfies (e.g., is greater than or equal to) a width difference threshold. The width difference threshold can be, for example, a particular percentage (e.g., 1%, 2%, 3%, 5%, 10%, 15%, or another percentage) of the maximum width 114 of the waveguide 106. In some implementations, when, for example, at least one sidewall of the waveguide 106 (e.g., along at least a portion of the length 112 of the waveguide 106) is tapered (e.g., angled inwardly relative to a first direction, as in FIG. 1 ), the width 114 of the waveguide 106 can be non-constant. Figure 1 , or angled outwardly relative to a first direction), is curved (e.g., is non-linear relative to the first direction, such as an elliptical, sinusoidal, fan-shaped, or another non-linear shape), is corrugated, and / or is rough (e.g., such that a difference between a maximum width 114 of the waveguide 106 along at least that portion and a minimum width 114 of the waveguide 106 satisfies a width difference threshold).

[0024] In this manner, the non-constant width 114 of the waveguide 106 (e.g., along at least the portion of the length 112 of the waveguide 106) enables the acousto-optic resonance in the electro-optic waveguide modulator 102 to be minimized. For example, the non-constant width 114 of the waveguide 106 can cause the amplitude of the acousto-optic resonance (e.g., the difference between the maximum and minimum values) to be reduced and / or the width of the acousto-optic resonance to be distributed over a larger frequency range (e.g., rather than concentrated over a narrow frequency range) compared to a waveguide 106 having a constant width. Figure 3 Additional description related to minimization of acousto-optic resonance due to the non-constant width 114 of the waveguide 106 is described.

[0025] As indicated above, provide Figure 1 As an example. Other examples may differ from the Figure 1 An example of a description is provided. Figure 1 The number and arrangement of the components shown in FIG. are provided as examples. Figure 1 There may be additional components, fewer components, different components, or differently arranged components compared to the components shown in FIG. Furthermore, it may be possible to implement the Figure 1 Two or more components shown in Figure 1The single component shown in can be implemented as multiple distributed components. Additionally or alternatively, Figure 1 The component collection (e.g., one or more components) shown in Figure 1 One or more functions performed by another set of components shown in FIG.

[0026] Figure 2 is a diagram of an example implementation 200 described herein. Figure 1 A top view of an electro-optical device 202 such as a Mach-Zehnder modulator chip (eg, supporting frequencies from 1 GHz to 50 GHz) or another type of electro-optical device (eg, for fiber optic communications) is shown. The electro-optical device 202 may include the Figure 1 A plurality of electro-optic waveguide modulators 102 are depicted.

[0027] like Figure 2 As shown in the figure, the electro-optical device 202 may include an input waveguide 204, a splitter 206, two arms of the electro-optical waveguide modulator 102 (shown as a first arm 102-1 and a second arm 102-2 of the electro-optical waveguide modulator), a combiner 208, one or more output waveguides 210 (shown as a single output waveguide 210) and a plurality of electrodes 212 (shown as a first plurality of electrodes 212-1 and a second plurality of electrodes 212-2).

[0028] Each of the input waveguide 204 and the output waveguide 210 may include a structure, channel, or other optical element configured to confine and propagate light within the waveguide. In some implementations, each waveguide may contain a material including at least InP, GaAs, AlGaAs, another III-V semiconductor material, an electro-optical material (e.g., lithium niobate (LiNbO3), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), and / or gallium phosphide (GaP)), and / or another material. Each of the splitter 206 and the combiner 208 may be configured to split or combine light, and may include, for example, a multi-mode interference (MMI) structure, a diffractive optical element (DOE), a segmented mirror, a beam splitter (e.g., a conventional beam splitter, a polarization beam splitter, or another type of beam splitter), and / or another type of optical element.

[0029] The input waveguide 204 can be configured to propagate the light to the splitter 206. The splitter 206 can be configured to split the light into a first portion of the light and a second portion of the light and provide the first portion of the light to the first arm 102-1 of the electro-optical waveguide modulator and provide the second portion of the light to the second arm 102-2 of the electro-optical waveguide modulator. Thus, the first arm 102-1 of the electro-optical waveguide modulator can be configured to receive the first portion of the light and propagate the first portion of the light to the combiner 208 (e.g., via the waveguide 106-1 of the first arm 102-1 of the electro-optical waveguide modulator, such as in the manner described herein with respect to Figure 1 ), and the second arm 102-2 of the electro-optical waveguide modulator can be configured to receive the second portion of the light and propagate the second portion of the light to the combiner 208 (e.g., via the waveguide 106-2 of the second electro-optical waveguide modulator 102-2, such as in a manner similar to that described herein for Figure 1 2 . The first plurality of electrodes 212-1 may be configured to apply a first electric field to the first arm 102-1 of the electro-optical waveguide modulator (e.g., to enable electro-optical modulation of a first portion of light as the first portion of light propagates through the first arm 102-1 of the electro-optical waveguide modulator), and the second plurality of electrodes 212-2 may be configured to apply a second electric field to the second arm 102-2 of the electro-optical waveguide modulator (e.g., to enable electro-optical modulation of a second portion of light as the second portion of light propagates through the second arm 102-2 of the electro-optical waveguide modulator). Thus, the combiner 208 may be configured to interferometrically combine the first portion of light with the second portion of light into an interferometric composite light, and provide the interferometric composite light to one or more output waveguides 210. The one or more output waveguides 210 may be configured to propagate the composite light away from the combiner 208, such as to an output of the electro-optical device 202 (or another component of the electro-optical device 202, Figure 2 not shown).

[0030] like Figure 2 As shown in , each of the first arm 102-1 of the electro-optical waveguide modulator and the second arm 102-2 of the electro-optical waveguide modulator may include a waveguide 106 having a non-constant width 114 (e.g., a non-constant width 114-1 of the waveguide 106-1 of the first arm 102-1 of the electro-optical waveguide modulator and a non-constant width 114-2 of the waveguide 106-2 of the second arm 102-2 of the electro-optical waveguide modulator). For example, Figure 2 As shown in FIG. 1 , the width 114-1-A of the waveguide 106-1 of the first arm 102-1 of the electro-optical waveguide modulator near the input end 120-1 of the waveguide 106-1 may be smaller than the width 114-1-B of the waveguide 106-1 near the output end 122-1 of the waveguide 106-1. Figure 2As shown in , the sidewalls of the waveguide 106-1 can be tapered (e.g., angled relative to a first direction parallel to the z-axis). As another example, Figure 2 As shown in , the width 114-2-A of the waveguide 106-2 of the second arm 102-2 of the electro-optical waveguide modulator near the input end 120-2 of the waveguide 106-2 may be smaller than the width 114-2-B of the waveguide 106-2 near the output end 122-2 of the waveguide 106-2. Figure 2 As shown in , the sidewalls of the waveguide 106-2 may be tapered (eg, angled relative to a first direction parallel to the z-axis). Figure 2 The respective sidewalls of waveguides 106-1 and 106-2 are shown as tapered, but the sidewalls may be tapered, curved, corrugated, and / or roughened (e.g., in accordance with the embodiments described herein). Figure 1 In a manner similar to that described above). Additionally, one or both of the sidewalls may be tapered, curved, corrugated, and / or roughened.

[0031] In this way, the non-constant width 114 of the waveguide 106 of the first arm 102-1 of the electro-optic waveguide modulator and the second arm 102-2 of the electro-optic waveguide modulator enables the corresponding acousto-optic resonances in the first arm 102-1 of the electro-optic waveguide modulator and the second arm 102-2 of the electro-optic waveguide modulator to be minimized in a manner similar to that described elsewhere herein.

[0032] As indicated above, provide Figure 2 As an example. Other examples may differ from the Figure 2 An example of a description is provided. Figure 2 The number and arrangement of the components shown in FIG. are provided as examples. Figure 2 There may be additional components, fewer components, different components, or differently arranged components compared to the components shown in FIG. Furthermore, it may be possible to implement the Figure 2 Two or more components shown in Figure 2 The single component shown in can be implemented as multiple distributed components. Additionally or alternatively, Figure 2 The component collection (e.g., one or more components) shown in Figure 2 One or more functions performed by another set of components shown in FIG.

[0033] Figure 33 is an illustration of an example graph 300 associated with an example implementation described herein. The graph 300 illustrates corresponding electro-optic resonances of different electro-optic waveguide modulators. For example, a first curve 302 associated with an electro-optic waveguide modulator having a constant width waveguide (e.g., a width of 1 μm) indicates acousto-optic resonances with large amplitudes (e.g., from -0.7 decibels (dB) to 0.5 decibels (dB)) concentrated in a narrow frequency range (e.g., from 2.0 GHz to 2.2 GHz). A second curve 304 associated with a first electro-optic waveguide modulator having a first non-constant width waveguide (e.g., a width ranging from 0.9 μm to 1.1 μm) indicates acousto-optic resonances with reduced amplitudes (e.g., from -0.4 dB to 0.3 dB) distributed across a wide frequency range (e.g., from 2.1 GHz to 2.7 GHz). A third curve 306 associated with a second electro-optic waveguide modulator having a second non-constant width waveguide (e.g., a width ranging from 0.8 μm to 1.2 μm) indicates an acousto-optic resonance having a further reduced amplitude (e.g., from -0.3 dB to 0.2 dB) distributed across an even wider frequency range (e.g., from 1.8 GHz to 2.7 GHz). In this manner, graph 300 illustrates an example of an electro-optic waveguide modulator having a non-constant width waveguide having an acousto-optic resonance that is minimized compared to the acousto-optic resonance of an electro-optic waveguide modulator having a constant width waveguide.

[0034] As indicated above, provide Figure 3 As an example. Other examples may differ from the Figure 3 An example of description.

[0035] The foregoing disclosure provides illustration and description, but is not intended to be exclusive or to limit the implementation to the precise form disclosed. Modifications and variations may be made in view of the disclosure above, or may be acquired from the practice of the implementation. In addition, unless the foregoing disclosure explicitly provides a reason why one or more implementations cannot be combined, any of the implementations described herein may be combined.

[0036] As used herein, the term "X material" or "X solution" (where X is a chemical component, such as indium phosphide (InP), gallium arsenide (GaAs)) indicates that at least a threshold percentage of X is included in the X material or X solution. The threshold percentage can be, for example, greater than or equal to 1%, 5%, 10%, 25%, 50%, 75%, 85%, 90%, 95% and / or 99%. As used herein, when a material or solution is referred to by a specific chemical name or chemical formula, the solution or material may include non-stoichiometric variations of the stoichiometrically exact formula identified by the chemical name. In addition, the solution or material may include ternary, quaternary and higher order compounds.

[0037] As used herein, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0038] Even if a specific combination of features is set forth in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various implementations. In fact, some of these features may be combined in a manner not specifically set forth in the claims and / or not disclosed in this specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of the various implementations includes the combination of each dependent claim with each other claim in the claim set. As used herein, a phrase referring to "at least one" in a list of items refers to any combination of those items including a single member. As an example, "at least one of the following: a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc and any combination with a plurality of said items.

[0039] Elements, actions, or instructions used herein should not be interpreted as critical or essential unless explicitly described as such. In addition, as used herein, the articles "a" and "an" are intended to include one or more items and can be used interchangeably with "one or more." In addition, as used herein, the article "the" is intended to include one or more items referenced in conjunction with the article "the" and can be used interchangeably with "one or more." In addition, as used herein, the term "set" is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and can be used interchangeably with "one or more." In the case of only meaning a set, the term "set" is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and can be used interchangeably with "one or more." Figure 1In the case of an article, the phrase "only one" or similar language is used. In addition, as used herein, the terms "has", "have", "having", etc. are intended to be open terms. In addition, the phrase "based on" is intended to mean "based at least in part on", unless otherwise explicitly stated. In addition, as used herein, the term "or" is intended to be inclusive when used continuously, and can be used interchangeably with "and / or", unless otherwise explicitly stated (for example, if used in combination with "any one" or "only one of them"). In addition, for the convenience of description, spatial relative terms (such as "below", "below", "above", "above", etc.) can be used herein to describe the relationship between an element or feature as illustrated in the figure and other elements or features. Spatial relative terms are intended to cover different orientations of devices, equipment and / or elements in use or operation in addition to the orientation depicted in the figure. Devices can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein can be interpreted in the same manner accordingly.

Claims

1. An electro-optical waveguide modulator, comprising: Deep etched waveguides; a first cladding layer disposed on a top surface of the deeply etched waveguide; as well as a second cladding layer, the second cladding layer being disposed on a bottom surface of the deep etched waveguide, wherein: The deep etched waveguide has a length extending in a first direction and a width extending in a second direction, and The width of the deep etched waveguide is non-constant along at least a portion of the length of the deep etched waveguide.

2. The electro-optical waveguide modulator of claim 1 , wherein the deeply etched waveguide contains a material comprising at least one of: indium phosphide (InP), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), lithium niobate (LiNbO 3 ), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), or gallium phosphide (GaP).

3. The electro-optic waveguide modulator of claim 1, wherein no cladding is provided on the sidewalls of the deep etched waveguide.

4. The electro-optic waveguide modulator of claim 1, wherein a passivation layer is provided on each sidewall of the deep etched waveguide.

5. The electro-optic waveguide modulator of claim 1 , wherein a difference between a maximum width of the deep etched waveguide and a minimum width of the deep etched waveguide along at least a portion of the length of the deep etched waveguide satisfies a width difference threshold, the width difference threshold being equal to 10% of the maximum width.

6. The electro-optic waveguide modulator of claim 1, wherein a sidewall of the deep etched waveguide along the at least a portion of the length of the deep etched waveguide is at least one of tapered, curved, corrugated, or roughened.

7. The electro-optic waveguide modulator of claim 1, wherein the deep etched waveguide comprises a core disposed within a central region of the deep etched waveguide.

8. An electro-optical waveguide modulator, comprising: Deep etched waveguides where: The deep etched waveguide has a length extending in a first direction and a width extending in a second direction, and A difference between a maximum width of the deep etched waveguide and a minimum width of the deep etched waveguide along at least a portion of the length of the deep etched waveguide satisfies a width difference threshold, the width difference threshold being equal to 10% of the maximum width.

9. The electro-optic waveguide modulator according to claim 8, further comprising: a first cladding layer disposed on a top surface of the deeply etched waveguide; as well as A second cladding layer is disposed on a bottom surface of the deep etched waveguide.

10. The electro-optic waveguide modulator of claim 8, wherein no cladding is provided on the sidewalls of the deep etched waveguide.

11. The electro-optic waveguide modulator of claim 8, wherein a passivation layer is provided on each sidewall of the deep etched waveguide.

12. The electro-optic waveguide modulator of claim 8, wherein the deeply etched waveguide contains a material comprising at least one of: indium phosphide (InP), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), lithium niobate (LiNbO3), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), or gallium phosphide (GaP).

13. The electro-optic waveguide modulator of claim 8, wherein a sidewall of the deep etched waveguide along the at least a portion of the length of the deep etched waveguide is angled relative to the first direction.

14. The electro-optic waveguide modulator of claim 8, wherein a sidewall of the deep etched waveguide along the at least a portion of the length of the deep etched waveguide is curved relative to the first direction.

15. An electro-optical device comprising: An electro-optic waveguide modulator having a deeply etched waveguide, wherein: The deep etched waveguide has a length extending in a first direction and a width extending in a second direction, and The width of the deep etched waveguide is non-constant along at least a portion of the length of the deep etched waveguide.

16. The electro-optic device of claim 15, wherein the electro-optic device is a Mach-Zehnder modulator chip.

17. The electro-optic device of claim 15, further comprising a first combiner and a second combiner, wherein: The electro-optical waveguide modulator is configured to receive light from the first combiner, to propagate the light via the deep-etched waveguide, and to provide the light to the second combiner.

18. The electro-optic device of claim 15, further comprising another electro-optic waveguide modulator having another deep etched waveguide, wherein: The further deep etched waveguide has a length extending in the first direction and a width extending in the second direction, and The width of the further deeply etched waveguide is non-constant along at least a portion of the length of the further deeply etched waveguide.

19. The electro-optic device of claim 15, wherein the sidewalls of the deep etched waveguide along the at least a portion of the length of the deep etched waveguide are at least one of tapered, curved, corrugated, or roughened.

20. The electro-optical device of claim 15, wherein the deeply etched waveguide contains a material comprising at least one of: indium phosphide (InP), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), lithium niobate (LiNbO3), silicon (Si), indium antimonide (InSb), gallium antimonide (GaSb), indium arsenide (InAs), or gallium phosphide (GaP).

Images