Optical modulation module and optical modulator

Abstract

The present disclosure provides an optical modulation module and an optical modulator. The optical modulation module includes a waveguide layer. The waveguide layer includes a flat plate portion, a first protrusion portion and a second protrusion portion disposed on the flat plate portion and extending in a first direction, wherein the distance between the top surfaces of the first protrusion portion and the bottom surface of the flat plate is H1, and a ridge portion disposed on the flat plate portion and extending in the first direction and disposed between the first protrusion portion and the second protrusion portion, wherein a first trench is formed between the ridge portion and the first protrusion portion and a second trench is formed between the ridge portion and the second protrusion portion, wherein the distance between the top surface of the ridge portion and the bottom surface of the flat plate is H2, where H2>H1.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to Chinese Patent Application No. 2023107941999, filed on June 29, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the technical field of optical waveguides, and in particular to optical modulation modules and optical modulators. [Background technology]

[0003] An optical waveguide is a dielectric device that guides the propagation of light waves, also known as a dielectric optical waveguide. Rectangular waveguides and ridge waveguides are two common waveguide structures. Rectangular waveguides allow for better light confinement and light transmission direction, but the effect of interaction between light transmitted within a rectangular waveguide and an external field (e.g., an external electric field) is relatively weak. Ridge waveguides allow for a relatively strong effect of interaction between light transmitted within a ridge waveguide and an external field (e.g., an external electric field), but ridge waveguides allow for relatively weak light confinement and light transmission direction within the ridge of the ridge waveguide. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION Embodiments of the present disclosure provide an optical modulation module and an optical modulator to improve the performance of the optical confinement and optical transmission direction of the waveguide layer so as to improve device performance. [Means for solving the problem]

[0005] According to one embodiment of the present disclosure, there is provided an optical modulation module. The optical modulation module includes a waveguide layer. The waveguide layer includes: a flat plate portion; a first protrusion portion and a second protrusion portion disposed on the flat plate portion and extending in a first direction, wherein a distance between a top surface of the first protrusion portion and a bottom surface of the flat plate is H1; and a ridge portion disposed on the flat plate portion and extending in the first direction and disposed between the first protrusion portion and the second protrusion portion, wherein a first trench is formed between the ridge portion and the first protrusion portion, and a second trench is formed between the ridge portion and the second protrusion portion, wherein a distance between a top surface of the ridge portion and a bottom surface of the flat plate is H2, where H2>H1.

[0006] In some embodiments, the first and second trenches have a gradually decreasing depth and / or a gradually decreasing width in the first direction.

[0007] In some embodiments, the first and second trenches have gradually increasing depths and / or gradually increasing widths in a first direction.

[0008] In some embodiments, the length of the first trench and the second trench in the first direction is less than or equal to the length of the ridge portion in the first direction.

[0009] In some embodiments, the optical modulation module further includes a substrate, an insulating layer disposed on the substrate, the waveguide layer being formed on the insulating layer, and a covering layer covering the waveguide layer, the covering layer having a refractive index of the material of the insulating layer and a refractive index of the material of the covering layer both lower than the refractive index of the material of the waveguide layer.

[0010] In some embodiments, the covering layer covers the ridge portion, the first trench and the second trench.

[0011] In some embodiments, the covering layer also covers at least a portion of the first protrusions and at least a portion of the second protrusions.

[0012] In some embodiments, the light modulation module further includes an electrode layer formed on the surface of the cover layer, or an electrode layer formed on the surface of at least one of the first protrusion and the second protrusion.

[0013] In some embodiments, the optical modulation module includes an electro-optical modulation module or a thermo-optical modulation module.

[0014] According to one aspect of the present disclosure, there is provided an optical modulator, the optical modulator including the optical modulation module of the previous aspect.

[0015] According to one or more embodiments of the present disclosure, the first trench and the second trench can hinder the diffusion of the optical mode field in the second direction, so that the light can propagate more centrally in the region where the ridge is located. Therefore, this design solution of the embodiments of the present disclosure can improve the optical confinement and light transmission direction performance of the waveguide layer to improve device performance.

[0016] It should be understood that the content described in this section is not intended to identify critical or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will be readily understood with reference to the following description.

[0017] More details, features and advantages of the present disclosure are disclosed in the following description of exemplary embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic cross-sectional view of a light modulation module according to some exemplary embodiments of the present disclosure. [Figure 2]1 is a schematic cross-sectional view of a light modulation module according to some exemplary embodiments of the present disclosure. [Figure 3] 1 is a schematic cross-sectional view of a light modulation module according to some exemplary embodiments of the present disclosure. [Figure 4] 1 is a schematic cross-sectional view of a light modulation module according to some exemplary embodiments of the present disclosure. [Figure 5A] 1 is a schematic structural perspective view of an optical modulation module according to some exemplary embodiments of the present disclosure. [Figure 5B] 1 is a schematic structural perspective view of an optical modulation module according to some exemplary embodiments of the present disclosure. [Figure 5C] 1 is a schematic structural perspective view of an optical modulation module according to some exemplary embodiments of the present disclosure. [Figure 5D] 1 is a schematic structural perspective view of an optical modulation module according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] Some merely exemplary embodiments are briefly described below. As will be understood by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. Accordingly, the accompanying drawings and descriptions are to be regarded as illustrative in nature and not as restrictive.

[0020] A ridge waveguide is a type of optical waveguide that has a series of excellent properties, such as a low fundamental mode cutoff frequency, a wide bandwidth, and low impedance. A ridge waveguide in the related art includes a flat layer and a ridge layer disposed on the flat layer, which are integrally formed. The interaction effect between light transmitted through such a ridge waveguide and an external acting field (e.g., an external electric field) is relatively strong, but the ridge waveguide has relatively weak optical confinement and optical transmission direction within the ridge of the ridge waveguide.

[0021] SUMMARY OF THE INVENTION Embodiments of the present disclosure provide an optical modulation module and an optical modulator to improve the performance of the optical confinement and optical transmission direction of the waveguide layer so as to improve device performance.

[0022] As shown in FIG. 1 , an optical modulation module 100 according to some embodiments of the present disclosure includes a waveguide layer 103. The waveguide layer 103 includes a flat plate portion 30, a first protrusion 31, a second protrusion 32, and a ridge portion 33. The first protrusion 31 and the second protrusion 32 are disposed on the flat plate portion 30 and extend in a first direction (not shown in the figure, the first direction is perpendicular to the paper). The distance between the top surfaces of the first protrusion 31 and the second protrusion 32 and the bottom surface of the flat plate portion 30 is H1. The ridge portion 33 is disposed on the flat plate portion 30 and extends in the first direction, and is disposed between the first protrusion 31 and the second protrusion 32. A first trench 34 is formed between the ridge portion 33 and the first protrusion 31, and a second trench 35 is formed between the ridge portion 33 and the second protrusion 32. The distance between the top surface of the ridge portion 33 and the bottom surface of the flat plate portion 30 is H2, where H2>H1.

[0023] The first direction may be the light transmission direction or the opposite direction of light transmission. In the optical modulation module 100 according to the embodiment of the present disclosure, the ridge portion 33 of the waveguide layer 103 is separated from the first protrusion 31 by a first trench 34 and from the second protrusion 32 by a second trench 35, and the distance between the top surface of the ridge portion 33 and the bottom surface of the flat portion 30 (i.e., the maximum material thickness in the region of the waveguide layer 103 where the ridge portion 33 is provided) is greater than the distance between the top surfaces of the first protrusion 31 and the second protrusion 32 and the bottom surface of the flat portion 30 (i.e., the maximum material thickness in the region of the waveguide layer 103 where the first protrusion 31 and the second protrusion 32 are provided). Therefore, the first trench 34 and the second trench 35 can hinder the diffusion of the optical mode field in the second direction, so that the light can be propagated more centrally in the region where the ridge portion 33 is located. Therefore, this design solution of the embodiment of the present disclosure can improve the optical confinement and optical transmission directional performance of the waveguide layer 103 so as to improve the device performance.

[0024] In the embodiments of the present disclosure, the optical modulation module 100 is not limited to a specific product type and may be, for example, an electro-optic modulation module or a thermo-optic modulation module. Electro-optic modulation modules perform phase modulation on transmitted light based on the electro-optic effect of the waveguide material and have a relatively fast modulation speed. Thermo-optic modulation modules perform phase modulation on transmitted light based on the thermo-optic effect of the waveguide material and have a relatively slow modulation speed but have the advantages of a large phase modulation range and high phase efficiency.

[0025] 2 , in some embodiments of the present disclosure, in addition to the waveguide layer 103, the optical modulation module 100 further includes a substrate 101, an insulating layer 102, and a covering layer 104. The substrate 101, the insulating layer 102, the waveguide layer 103, and the covering layer 104 are arranged in this order, the waveguide layer 103 is formed on the insulating layer 102, and the refractive index of the material of the insulating layer 102 and the refractive index of the material of the covering layer 104 are both lower than the refractive index of the material of the waveguide layer 103. The insulating layer 102 and the covering layer 104 have lower refractive indices than the waveguide layer 103, so that light can be confined to propagate mainly within the waveguide layer 103, achieving the advantages of the ridge waveguide described above.

[0026] 3 , in some embodiments, the covering layer 104 covers the ridge portion 33, the first trench 34, and the second trench 35, and also covers at least a portion of the first protrusion 31 and at least a portion of the second protrusion 32. In this manner, the electrode layer 105 can be provided on the covering layer 104, and the covering area and thickness of the covering layer 104 can be adjusted to flexibly adjust the design pattern and arrangement height of the electrodes in the electrode layer 105 so as to match the electrical transmission speed with the optical transmission speed as closely as possible. As shown in FIG. 3 , according to some embodiments of the present disclosure, the optical modulation module 100 further includes an electrode layer 105 formed on the surface of the covering layer 104.

[0027] In other embodiments of the present disclosure, the covering layer 104 may also cover only the ridge portion 33, the first trench 34, and the second trench 35, and the electrode layer 105 may be formed directly on the surface of the waveguide layer 103. As shown in FIG. 4 , according to some embodiments of the present disclosure, the optical modulation module 100 further includes an electrode layer 105 formed on a surface of at least one of the first protrusion 31 and the second protrusion 32.

[0028] 5A, in some embodiments of the present disclosure, a first trench 34 is formed between the ridge portion 33 and the first protrusion 31, and a second trench 35 is formed between the ridge portion 33 and the second protrusion 32. The widths W of the first trench 34 and the second trench 35 gradually decrease in the first direction.

[0029] 5B, in some embodiments of the present disclosure, a first trench 34 is formed between the ridge portion 33 and the first protrusion 31, and a second trench 35 is formed between the ridge portion 33 and the second protrusion 32. The widths W of the first trench 34 and the second trench 35 gradually decrease in the first direction.

[0030] 5C, in some embodiments of the present disclosure, a first trench 34 is formed between the ridge portion 33 and the first protrusion 31, and a second trench 35 is formed between the ridge portion 33 and the second protrusion 32. In a first direction, the depth H of the first trench 34 and the second trench 35 gradually decreases, and the width also gradually decreases until the trenches disappear.

[0031] 5D, in some embodiments of the present disclosure, a first trench 34 is formed between the ridge portion 33 and the first protrusion 31, and a second trench 35 is formed between the ridge portion 33 and the second protrusion 32. The depths and widths of the first trench 34 and the second trench 35 gradually increase from zero in a first direction.

[0032] In some embodiments of the present disclosure, the length of the first trench 34 and the second trench 35 in the first direction can be shorter than the length of the ridge portion 33 in the first direction, as shown in Figure 5A. In other embodiments of the present disclosure, the length of the first trench and the second trench in the first direction can also be equal to the length of the ridge portion in the first direction, i.e., the first trench and the second trench extend through the waveguide layer in the first direction.

[0033] In the above-described embodiment, the trend of change in the depth and / or width of the first trench 34 and the second trench 35 can be determined based on the light transmission direction and the specific type of photonic element optically coupled to the optical modulation module 100. The depth and / or width of the first trench 34 and the second trench 35 are designed to change gradually, which can more gradually prevent the diffusion of the optical mode field in the second direction, and therefore the optical modulation module 100 can perform gradual and stable spot size modulation, which contributes to reducing optical transmission loss.

[0034] An embodiment of the present disclosure further provides an optical modulator including the optical modulation module 100 according to any one of the above-described embodiments. The optical modulator is, for example, a thermo-optical modulator or an electro-optical modulator. The electro-optical modulator may be, for example, a Mach-Zehnder modulator, and may include an optical splitter element, an optical combiner element, etc. in addition to the optical modulation module 100.

[0035] Based on the above design of the optical modulation module 100 and the beneficial effects achieved, the optical modulator has correspondingly improved device performance, lower optical transmission loss, and higher modulation efficiency.

[0036] In this description, the orientations, positional relationships, or dimensions indicated by terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are orientations, positional relationships, or dimensions shown based on the accompanying drawings, and it should be understood that these terms are used merely for ease of description and do not indicate or imply that the referred-to devices or elements must have a particular orientation, be configured, and operate in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present disclosure.

[0037] Additionally, terms such as "first," "second," and "third" are merely descriptive and should not be construed as indicating or implying relative importance or the number of technical features shown. Thus, features defined with "first," "second," and "third" can explicitly or implicitly include one or more features. In the description of this disclosure, the term "plurality" means two or more unless explicitly and specifically defined otherwise.

[0038] In this disclosure, unless expressly stated or otherwise defined, terms such as "attach," "connect," "connected," and "secure" should be interpreted broadly, for example, they may be fixed, detachable, or integral connections, may be mechanical or electrical connections or communications, may be direct connections or indirect connections through intermediate media, or may be internal communications or interactions between two elements. For those skilled in the art, the specific meanings of the above terms in this disclosure may be understood according to the specific environment.

[0039] In this disclosure, unless otherwise specified or defined, a phrase that a first feature is "above" or "below" a second feature can include cases where the first feature directly contacts the second feature, or cases where the first and second features are not in direct contact but are contacted via another feature between them. Furthermore, a first feature being "above," "above," or "on" a second feature can include cases where the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature can include cases where the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower level than the second feature.

[0040] This description provides many different embodiments or examples that can be used to implement the present disclosure. It should be understood that these various embodiments or examples are purely illustrative and are not intended to limit the scope of protection of the present disclosure in any way. Based on the disclosure of the description of the present disclosure, those skilled in the art will be able to think of various modifications or alternatives. All of these modifications or alternatives shall fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be governed by the scope of protection of the claims. [Explanation of symbols]

[0041] 100 Optical Modulation Module 101 Substrate 102 Insulating layer 103 Waveguide layer 104 Covering layer 105 Electrode layer 30 Flat plate part 31 First protrusion 32 Second protrusion 33 Ridge 34 First Trench 35 Second Trench

Claims

1. 1. An optical modulation module including a waveguide layer, The waveguide layer comprises: A flat plate portion; a first protrusion and a second protrusion disposed on the flat plate portion and extending in a first direction, wherein a distance H1 is between a top surface of the first protrusion and a bottom surface of the flat plate portion; a ridge portion disposed on the flat plate portion, extending in the first direction, and disposed between the first protruding portion and the second protruding portion, wherein a first trench is formed between the ridge portion and the first protruding portion, a second trench is formed between the ridge portion and the second protruding portion, and a distance between a top surface of the ridge portion and the bottom surface of the flat plate portion is H2, where H2>H1; an optical modulation module comprising:

2. the depth of the first trench and the second trench gradually decreases in the first direction, and / or the width of the first trench and the second trench gradually decreases in the first direction; The optical modulation module according to claim 1 .

3. the depth of the first trench and the second trench gradually increases in the first direction, and / or the width of the first trench and the second trench gradually increases in the first direction; The optical modulation module according to claim 1 .

4. a length of the first trench and the second trench in the first direction is equal to or less than a length of the ridge portion in the first direction; The optical modulation module according to claim 1 .

5. A substrate; an insulating layer disposed on the substrate, the waveguide layer being formed on the insulating layer; a covering layer covering the waveguide layer, the refractive index of the material of the insulating layer and the refractive index of the material of the covering layer both being lower than the refractive index of the material of the waveguide layer; The optical modulation module of claim 1 , further comprising:

6. the covering layer covers the ridge portion, the first trench, and the second trench; The optical modulation module according to claim 5 .

7. the covering layer also covers at least a portion of the first protrusion and at least a portion of the second protrusion; The optical modulation module according to claim 6 .

8. an electrode layer formed on the surface of the coating layer; or an electrode layer formed on a surface of at least one of the first protrusion and the second protrusion; The optical modulation module according to claim 1 , further comprising:

9. including an electro-optical modulation module or a thermo-optical modulation module; The optical modulation module according to claim 1 .

10. An optical modulator comprising an optical modulation module according to any one of claims 1 to 9.

Images