Spot size converter and optical device

Abstract

The present invention relates to a spot size converter (100) and an optical device (1) including the spot size converter (100). The spot size converter (100) has a first end face (100a) and a second end face (100b) that are parallel to each other, and further includes a substrate (101), an insulating layer (102) located on the side of the substrate (101) and arranged in this order in a direction away from the substrate (101), a first waveguide (103), and a covering layer (104). The first waveguide (103) includes a flat layer (31) and a raised layer (32). The flat layer (31) includes a first wide end (31a) extending to the first end face (100a) and a first narrow end (31b) extending to or at a distance from the second end face (100b), and the flat layer (31) has a width that decreases at a gradient from the first wide end (31a) to the first narrow end (31b) and includes a first equal-width portion (311) adjacent to the first narrow end (31b). The raised layer (32) includes a second wide end (32a) extending to the first end face (100a) and a second narrow end (32b) at a distance from the first narrow end (31b). The raised layer (32) has a width that decreases at a gradient from the second wide end (32a) to the second narrow end (32b) and includes a second equal-width portion (321) adjacent to the second narrow end (32b). The covering layer (104) extends to the second end face (100b) and extends to cover at least one end of the second equal-width portion remote from the second end face (100b).

Description

[Technical field]

[0001] Books The disclosure relates to the field of photonic technology, and in particular to spot size converters and photonic devices. [Background technology]

[0002] An optical waveguide is a dielectric device that guides the propagation of light waves in it, also called a dielectric optical waveguide. There are mainly two types of optical waveguides: one type is the integrated optical waveguide, which includes planar dielectric optical waveguides and slab dielectric optical waveguides, which generally work as a part of an optoelectronic integrated device and are therefore called integrated optical waveguides, and the other type is the cylindrical optical waveguide, which is usually called an optical fiber.

[0003] The technique of coupling integrated optical waveguides to optical fibers has wide and important applications in the fields of optical communications, microwave photonics, laser beam deflection, wavefront modulation, etc. End coupling is a common method used to couple integrated optical waveguides to optical fibers. Summary of the Invention [Problem to be solved by the invention]

[0004] However, how to improve the coupling efficiency between an integrated optical waveguide and an optical fiber has always been an important topic of research for those skilled in the art due to the large difference in spot size between the integrated optical waveguide and the optical fiber. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, a spot size converter is provided that includes a first end face configured to be coupled to an integrated optical waveguide and a second end face parallel to the first end face and configured to be coupled to an optical fiber.

[0006] The spot size converter is A substrate; an insulating layer located on a side of the substrate and having an orthogonal projection onto the substrate substantially coinciding with the substrate; a first waveguide located on a side of the insulating layer remote from the substrate, a flat layer including a first wide end portion extending to a first end surface and a first narrow end portion extending to or at a distance from a second end surface, the flat layer having a width that decreases at a gradient from the first wide end portion to the first narrow end portion and including a first equal width portion adjacent to the first narrow end portion, the width direction being parallel to the substrate and parallel to the first end surface; a raised layer stacked on a side of the planar layer away from the substrate and including a second wide end extending to the first edge and a second narrow end having a distance from the first narrow end, the raised layer having a gradient decreasing width from the second wide end to the second narrow end and including a second equal width portion adjacent the second narrow end; A first waveguide including: a covering layer located on a side of the first waveguide remote from the substrate, extending to the second end face and covering at least one end of the second equal-width portion remote from the second end face, a portion of the covering layer proximate to the second end face and a portion of the insulating layer proximate to the second end face forming a second waveguide; Equipped with.

[0007] In some embodiments, the flat layer includes a first equal width portion, a first gradually diverging portion, a third equal width portion, a second gradually diverging portion, and a fourth equal width portion, arranged sequentially in a direction away from the first narrow end, and the raised layer includes a second equal width portion, a third gradually diverging portion, and a fifth equal width portion, arranged sequentially in a direction away from the second narrow end, and any of the first gradually diverging portion, the second gradually diverging portion, and the third gradually diverging portion have a width that gradually increases in a direction away from the second end surface.

[0008] In some embodiments, the cover layer extends over at least one end of the third diverging portion remote from the second end surface.

[0009] In some embodiments, the orthogonal projection of the coating layer onto the substrate is rectangular, and the width of the coating layer is greater than the width of the third equal width portion.

[0010] In some embodiments, the cladding layer covers the entire first waveguide, the cladding layer has a width that increases at a gradient away from the second end face, and the cladding layer includes a sixth equal-width portion, a fourth gradually diverging portion, and a seventh equal-width portion arranged sequentially in a direction away from the second end face, the fourth gradually diverging portion having a width that gradually increases in a direction away from the second end face, and the sixth equal-width portion having a width greater than a width of the third equal-width portion.

[0011] In some embodiments, the cladding layer covers the entire first waveguide, the cladding layer has a width that increases at a gradient away from the second end face, and the cladding layer comprises a sixth equal-width portion and a seventh equal-width portion sequentially arranged in the direction away from the second end face, the sixth equal-width portion having a width greater than a width of the third equal-width portion.

[0012] In some embodiments, the coating layer includes an eighth equal width portion, a tapered portion, and a ninth equal width portion arranged sequentially in a direction away from the second end face, the tapered portion having a width that gradually decreases in a direction away from the second end face, and the ninth equal width portion having a width greater than the width of the third equal width portion.

[0013] In some embodiments, the cladding layer covers the entire first waveguide, and the cladding layer further includes a tenth portion located on a side of the ninth equal-width portion away from the second end face, the tenth portion having a width greater than the width of the ninth equal-width portion.

[0014] In some embodiments, the spot size converter further includes first and second sides arranged parallel to each other and intersecting the first and second end faces, and the fourth equal-width portion extends to the first and second sides.

[0015] In some embodiments, the width of the top of the first narrow end is 400 nanometers or less.

[0016] In some embodiments, the width of the coating layer at the second end surface is greater than or equal to 1 micron and less than or equal to 20 microns.

[0017] In some embodiments, in a direction away from the second end surface, the widths of the first and third diverging portions increase linearly and the width of the second diverging portion increases non-linearly.

[0018] In some embodiments, the first equal width portion is prismatic and has a triangular or trapezoidal cross-section parallel to the first end face.

[0019] In some embodiments, the second equal width portion is prismatic and has a triangular or trapezoidal cross-section parallel to the first end face.

[0020] In some embodiments, the first end face is an input end of the spot size converter and the second end face is an output end of the spot size converter, or the second end face is an input end of the spot size converter and the first end face is an output end of the spot size converter.

[0021] According to another aspect of the present disclosure, there is provided an optical device comprising a spot size converter according to any of the above technical solutions.

[0022] These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0023] Further details, features and advantages of the present disclosure are disclosed in the following description of exemplary embodiments, with reference to the accompanying drawings. [Brief description of the drawings]

[0024] [Figure 1A] 1 is a schematic structural perspective view of a spot size converter according to some exemplary embodiments of the present disclosure; FIG. [Figure 1B]2A-2C are schematic diagrams of a first end face of a spot size converter according to some exemplary embodiments of the present disclosure. [Figure 1C] 4A-4C are schematic diagrams of a second end face of a spot size converter according to some exemplary embodiments of the present disclosure. [Figure 2A] FIG. 2 is a schematic structural perspective view of a first waveguide according to some exemplary embodiments of the present disclosure. [Figure 2B] FIG. 2 is a schematic structural top view of a first waveguide according to some exemplary embodiments of the present disclosure. [Diagram 3] 1A-1C are schematic structural top views of spot size converters according to some other exemplary embodiments of the present disclosure. [Figure 4] 1A-1C are schematic structural top views of spot size converters according to still some other exemplary embodiments of the present disclosure. [Diagram 5] 1A-1C are schematic structural top views of spot size converters according to still some other exemplary embodiments of the present disclosure. [Figure 6] 1A-1C are schematic structural top views of spot size converters according to still some other exemplary embodiments of the present disclosure. [Figure 7] 1A-1D are schematic structural diagrams of optical devices according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Only some exemplary embodiments are briefly described below. As can be understood by those skilled in the art, the described embodiments can 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 restrictive.

[0026] Although some related art spot size converters can functionally realize coupling between an integrated optical waveguide and an optical fiber, the coupling efficiency between the integrated optical waveguide and the optical fiber is not high due to the large difference in spot size between them, resulting in a large loss of optical energy. For example, the spot size of an integrated optical waveguide is generally on the order of hundreds of nanometers, while the spot size of an optical fiber, such as a flat-ended optical fiber, is on the order of tens of microns. The lost optical energy may lead to significant heating of the coupling end face, thereby affecting the reliability and service life of the device. The coupling efficiency can be understood to be the ratio of the optical power emitted by the integrated optical waveguide to the optical power received by the optical fiber, or the ratio of the optical power emitted by the optical fiber to the optical power received by the integrated optical waveguide.

[0027] Embodiments of the present disclosure provide spot size converters and optical devices that can not only perform spot size conversion but also have low optical loss during spot size conversion, thereby improving the coupling efficiency between integrated optical waveguides and optical fibers.

[0028] 1A, 1B, 1C, 2A, and 2B, a spot size converter 100 according to some embodiments of the present disclosure includes a first end face 100a configured to be coupled to an integrated optical waveguide (not shown) and a second end face 100b parallel to the first end face 100a and configured to be coupled to an optical fiber (not shown). The spot size converter 100 structurally includes a substrate 101, an insulating layer 102, a first waveguide 103, and a cladding layer 104, which are located on a side of the substrate 101 and arranged in sequence in a direction away from the substrate 101.

[0029] The orthogonal projection of the insulating layer 102 onto the substrate 101 substantially coincides with the substrate 101. The first waveguide 103 comprises a flat layer 31 and a raised layer 32 stacked on the side of the flat layer 31 remote from the substrate 101. The flat layer 31 comprises a first wide end 31a extending to the first end face 100a and a first narrow end 31b extending to the second end face 100b. The flat layer 31 has a width that decreases in a gradient from the first wide end 31a to the first narrow end 31b and comprises a first equal width portion 311 adjacent to the first narrow end 31b. The raised layer 32 comprises a second wide end 32a extending to the first end face 100a and a second narrow end 32b having a distance from the first narrow end 31b. The raised layer 32 has a width that decreases at a gradient from the second wide end 32a to the second narrow end 32b, with a second equal-width portion 321 adjacent the second narrow end 32b. The cover layer 104 extends to the second end face 100b and extends to cover at least one end of the second equal-width portion 321 remote from the second end face 100b. A portion of the cover layer 104 proximate the second end face 100b and a portion of the insulating layer 102 proximate the second end face 100b together form the second waveguide 42.

[0030] As shown in FIG. 1A, in addition to having a first end face 100a and a second end face 100b, the spot size converter 100 further comprises a first side face 100c and a second side face 100d arranged parallel to each other and perpendicular to the first end face 100a and the second end face 100b. The first end face 100a is configured to be coupled to an integrated optical waveguide, and the second end face 100b is configured to be coupled to an optical fiber. The first end face 100a can be used as an optical input end face of the spot size converter 100, and the second end face 100b can be used as an optical output end face of the spot size converter 100. Specifically, light is input from the first wide end 31a and the second wide end 32a of the first waveguide 103 and output from the second waveguide 42. Also, the first end face 100a can be used as an optical output end face of the spot size converter 100, and the second end face 100b can be used as an optical input end face of the spot size converter 100. Specifically, light is input from the second waveguide 42 and output from the first wide end 31a and the second wide end 32a of the first waveguide 103.

[0031] In the embodiment of the present disclosure, the width direction is defined as being parallel to the substrate 101 and the first end face 100a, the length direction is parallel to the substrate 101 and perpendicular to the first end face 100a, and the height direction and thickness direction are defined as being perpendicular to the substrate 101. For a three-dimensional structure having a certain thickness or height, taking the first equal width portion 311 as an example, it can be understood that its width is the width of its orthogonal projection onto the substrate 101, and its length is the length of its orthogonal projection onto the substrate 101. With the orthogonal projection of the insulating layer 102 onto the substrate 101, which is substantially coincident with the substrate 101, it can be understood that when viewed from a direction perpendicular to the substrate 101 (e.g., in a top view direction), the contour shape of the orthogonal projection and the substrate are considered to be consistent and coincident, ignoring process errors.

[0032] In the embodiment of the present disclosure, the refractive index n1 of the first waveguide 103, the refractive index n2 of the covering layer 104, the refractive index n3 of the insulating layer 102, and the refractive index n4 of the substrate 101 satisfy n1>n2>n3.

[0033] As shown in FIG. 1A, the first waveguide 103 is a ridged waveguide with a series of excellent properties, such as low fundamental mode cutoff frequency, wide bandwidth, and low impedance. The refractive index of the insulating layer 102 and the refractive index of the cladding layer 104 are smaller than those of the first waveguide 103, so that the light can be mainly restricted to transmission in the ridged waveguide, so as to achieve the above advantages of the ridged waveguide. A part of the cladding layer 104 close to the second end face 100b and a part of the insulating layer 102 close to the second end face 100b together form the second waveguide 42. The size of the second waveguide 42 is larger than the size of the first narrow end 31b and can match the spot size of the optical fiber, thereby improving the coupling to the optical fiber at the second end face 100b.

[0034] When light is transmitted from the first end face 100a to the second end face 100b of the spot size converter 100, a part of the light leaks from the first equal-width portion 311 to the second waveguide 42 and continues to be transmitted through the second waveguide 42 until the light reaches the second end face 100b, thereby forming a spot size match with that of the optical fiber at the second end face 100b. On the other hand, when light is transmitted from the second end face 100b to the first end face 100a of the spot size converter 100, the light enters the first equal-width portion 311 from the second waveguide 42, i.e., the light enters the first waveguide 103 through the second waveguide 42. The refractive index of the substrate 101 is generally larger than that of the insulating layer 102. The substrate 101 is, for example, a silicon substrate.

[0035] The specific structural shape of the first waveguide 103 is not limited. As shown in Figures 2A and 2B, in some embodiments, the first waveguide 103 is of an axially symmetric structure, and the symmetry axis of the first waveguide 103 is perpendicular to the second end face 100b. The flat layer 31 includes a first equal width portion 311, a first gradually expanding portion 312, a third equal width portion 313, a second gradually expanding portion 314, and a fourth equal width portion 315, which are sequentially arranged in a direction away from the first narrow end 31b. The raised layer 32 includes a second equal width portion 321, a third gradually expanding portion 322, and a fifth equal width portion 323, which are sequentially arranged in a direction away from the second narrow end 32b. Any of the first gradually diverging portion 312, the second gradually diverging portion 314, and the third gradually diverging portion 322 have a width that gradually increases in a direction away from the second end surface 100b.

[0036] It should be noted that the embodiments of the present disclosure are not limited to designing the first waveguide as an axially symmetric structure, and the first waveguide can also be of an asymmetric structure. For example, the flat layer and / or the raised layer of the first waveguide can also have a gradient change only on a single side.

[0037] The flat layer 31 and the bump layer 32 of the first waveguide 103 can each be formed by one patterning step. For example, the flat layer 31 is first formed by one patterning step, and the bump layer 32 is formed by another patterning step. Each patterning step can include film formation, photoresist coating, exposure, development, etching, photoresist stripping, and other steps. The exposure step requires the use of a mask to block the non-etched areas.

[0038] The flat layer 31 and the bump layer 32 of the first waveguide 103 can also be formed by one patterning step with two exposures. For example, after film formation and photoresist coating, the film pattern in the area where the first waveguide 103 is located is first formed by one exposure and subsequent procedure, and then the final structure of the flat layer 31 and the bump layer 32 is formed by another exposure and subsequent procedure.

[0039] In the embodiment of the present disclosure, in the direction away from the first end face 100a, the flat layer 31 of the first waveguide 103 has a width that decreases with a gradient, and the ridge layer 32 also has a width that decreases with a gradient. Due to the gradient structural characteristics of the flat layer 31 and the ridge layer 32, a relatively moderate spot size modulation can be performed on the light transmitted in the first waveguide 103, so as to minimize the light transmission loss and improve the coupling efficiency of the spot size converter 100.

[0040] In addition, a certain distance is provided between the second narrow end 32b of the bump layer 32 and the first narrow end 31b of the flat layer 31 of the first waveguide 103. With this design, the first equal-width portion 311 can provide steady-state spot size modulation for the light output from (or entering) the first waveguide 103, facilitating the improvement of the stability of the light transmission, and due to the aforementioned distance, when the flat layer 31 and the bump layer 32 are manufactured by two patterning steps or one patterning step with two exposures, the requirement of the alignment accuracy of the mask can be reduced, facilitating the reduction of the difficulty and cost of the process control.

[0041] In some embodiments of the present disclosure, the first equal-width portion 311 is prismatic, and its cross section parallel to the first end face 100a is triangular or trapezoidal, for example in the shape of an isosceles triangle or an isosceles trapezoid. When light is transmitted from the first end face 100a to the second end face 100b of the spot size converter 100, this design allows more light to leak from the first equal-width portion 311 into the second waveguide 42. When light is transmitted from the second end face 100b to the first end face 100a of the spot size converter 100, the design allows light to more easily enter the first equal-width portion 311 from the second waveguide 42, i.e., more light is allowed to enter the first waveguide 103 through the second waveguide 42. Therefore, the above-mentioned cross-sectional shape design of the first equal-width portion 311 can further improve the coupling efficiency between the integrated optical waveguide and the optical fiber. In addition, the second equal-width portion 321 can also be prismatic, and its cross section parallel to the first end face 100a can also be in the shape of a triangle or a trapezoid, for example, an isosceles triangle or an isosceles trapezoid, so as to allow light to enter the flat layer 31 from the second equal-width portion 321 more easily.

[0042] In an embodiment of the present disclosure, in a direction away from the second end face 100b, the width change trend of the first gradually diverging portion 312 can be linear or nonlinear, the width change trend of the second gradually diverging portion 314 can be linear or nonlinear, and the width change trend of the third gradually diverging portion 322 can be linear or nonlinear. As shown in FIG. 2B, in this embodiment, in a direction away from the second end face 100b, the widths of the first gradually diverging portion 312 and the third gradually diverging portion 322 increase linearly and gradually, and the width of the second gradually diverging portion 314 increases nonlinearly and gradually.

[0043] The linear width change trend can realize smooth modulation of spot size at a shorter distance, the non-linear width change trend can realize more moderate and stable modulation of spot size, and the shape curve of the gradually changing part can be flexibly adjusted according to specific requirements to obtain a better adjustment effect.

[0044] As shown in Figures 1A and 1C, in some embodiments of the present disclosure, the first narrow end 31b of the flat layer 31 extends to the second end face 100b. In this manner, the first narrow end 31b also serves as part of a port for outputting to or receiving input from an optical fiber. As shown in Figure 3, in some other embodiments of the present disclosure, there may be a distance g between the first narrow end 31b of the flat layer 31 and the second end face 100b such that the ends of the insulating layer 102 and the coating layer 104 that extend to the second end face 100b serve as ports for outputting to or receiving input from an optical fiber.

[0045] 1A and 2A, the fourth equal-width portion 315 of the planar layer 31 can also extend to the first side 100c and the second side 100d, i.e., the width of the fourth equal-width portion 315 is maximized. In this way, the spot size converter 100 can be adapted to an integrated optical waveguide having a larger spot size, thereby improving the applicability of the spot size converter 100.

[0046] In some embodiments of the present disclosure, the top of the first narrow end 31b has a width w6 of 400 nanometers or less, and / or the width w4 of the covering layer 104 at the second end face is 1 micron or more and 20 microns or less. The specific structure size of the spot size converter 100 can be specifically designed according to the performance requirements of the device in combination with experience, which is not particularly limited in the present disclosure.

[0047] A part of the coating layer 104 and a part of the insulating layer 102 close to the second end face 100b together form a second waveguide 42 having a lower refractive index. One end of the coating layer 104 needs to extend to the second end face 100b, and the other end needs to extend to cover at least the second equal-width portion 321, i.e., to at least the end of the second equal-width portion 321 away from the second end face 100b. The specific shape design of the coating layer 104 is not limited. Adjusting the shape and size of the coating layer 104 is to adjust the structure size of the second waveguide 42, and then adjust the size of the spot size of the second end face 100b. Therefore, the shape and size of the coating layer 104 can be flexibly modulated as needed to achieve the best match with the spot size of the optical fiber.

[0048] In some embodiments of the present disclosure, the covering layer 104 is of an axially symmetric structure with respect to the symmetry axis, and the covering layer 104 extends to cover at least one end of the third gradually diverging portion 322 away from the second end face 100b, so as to fully achieve its function in the second waveguide 42 and reduce the leakage loss of light. The embodiments of the present disclosure are not limited to designing the covering layer as an axially symmetric structure, and the covering layer can also be of an asymmetric structure.

[0049] As shown in FIG. 3, in some embodiments, the covering layer 104 is of axially symmetrical structure with respect to the axis of symmetry, the covering layer 104 extends to cover at least the end of the third gradually expanding portion 322 away from the second end face 100b, the orthogonal projection of the covering layer 104 on the substrate 101 is rectangular, and the width of the covering layer 104 (equal to the width w4 of the covering layer 104 at the second end face) is greater than the width w3 of the third equal width portion 313. Similarly, in these embodiments, the covering layer can also be of asymmetrical structure. The orthogonal projection of the covering layer 104 on the substrate 101 is rectangular, which means that the contour of the orthogonal projection on the substrate 101 is rectangular, and the sidewalls of the covering layer 104 can be perpendicular to the substrate 101 or can form other included angles.

[0050] As shown in FIG. 4, in some other embodiments, the covering layer 104 is of axially symmetrical structure with respect to the axis of symmetry, the covering layer 104 extends to cover at least the end of the third gradually expanding portion 322 away from the second end face 100b, and the covering layer 104 includes an eighth equal width portion 411, a tapered portion 412, and a ninth equal width portion 413 arranged in sequence in a direction away from the second end face 100b. The tapered portion 412 has a width that gradually decreases in a direction away from the second end face 100b, and the ninth equal width portion 413 has a width w5 that is larger than the width w3 of the third equal width portion 313. Obviously, the width of the eighth equal width portion 411 (equal to the width w4 of the covering layer 104 at the second end face) is also larger than the width w3 of the third equal width portion 313. Similarly, in these embodiments, the covering layer can also be of asymmetrical structure, for example, can have a gradient change only on a single side.

[0051] In addition, the cladding layer can also be designed to cover the entire first waveguide. For example, the cladding layer further comprises a tenth portion located on the side of the ninth equal-width portion away from the second end face, the tenth portion having a width greater than the width of the ninth equal-width portion. In a particular embodiment, on the side of the ninth equal-width portion away from the second end face, the width of the cladding layer increases in a gradient to cover the entire first waveguide.

[0052] In this design, the width of the cladding layer 104 increases in a gradient away from the first end face 100a, opposite to the width change trend of the flat layer 31 and the ridge layer 32 of the first waveguide 103. This design is equivalent to an increased size of the second waveguide 42. When light is transmitted from the first end face 100a to the second end face 100b of the spot size converter 100, more light leaking from the first waveguide 103 can enter the second waveguide 42 and can be moderately modulated in spot size by the gradient structure of the second waveguide 42 so as to reduce light loss. When light is transmitted from the second end face 100b to the first end face 100a of the spot size converter 100, more light can enter the second waveguide 42, be moderately modulated in spot size by the gradient structure of the second waveguide 42, and then enter the first waveguide 103. Therefore, the shape design of the coating layer 104 can further improve the coupling efficiency between the integrated optical waveguide and the optical fiber.

[0053] As shown in FIG. 5, in some other embodiments, the cladding layer 104 covers the entire first waveguide 103 and has an axially symmetric structure with respect to the axis of symmetry, and the cladding layer 104 has a width that increases with a gradient in the direction away from the second end face 100b. The cladding layer 104 includes a sixth equal width portion 421, a fourth gradually expanding portion 422, and a seventh equal width portion 423, which are arranged in sequence in the direction away from the second end face 100b. The sixth equal width portion 421 has a width greater than the width w3 of the third equal width portion 313 (equal to the width w4 of the cladding layer 104 at the second end face), and the fourth gradually expanding portion 422 has a width that gradually increases in the direction away from the second end face 100b. Similarly, in these embodiments, the cladding layer can also be of an asymmetric structure, for example, having a gradient change only on a single side.

[0054] As shown in FIG. 6, in some other embodiments, the cladding layer 104 covers the entire first waveguide 103 and has an axially symmetric structure with respect to the axis of symmetry, and the cladding layer 104 has a width that increases with a gradient in a direction away from the second end face 100b. The cladding layer 104 includes a sixth equal width portion 431 and a seventh equal width portion 433 arranged sequentially in a direction away from the second end face 100b. The sixth equal width portion 431 has a width greater than the width w3 of the third equal width portion 313 (equal to the width w4 of the cladding layer 104 at the second end face). Similarly, in these embodiments, the cladding layer can also be of an asymmetric structure, for example, having a gradient change only on a single side.

[0055] 7, an embodiment of the present disclosure further provides an optical device 1 including a spot size converter 100 according to any of the previous embodiments. The specific product type of the optical device 1 is not limited, and can be, for example, an electro-optic modulator, a splitter, a star coupler, a variable optical attenuator (VOA), an optical switch, an interleaver, an array waveguide grating (AWG), etc.

[0056] The spot size converter 100 is integrated in the optical device 1. Because the spot size converter 100 has a higher coupling efficiency, the optical loss of the optical device 1 is smaller and the performance is improved.

[0057] In this description, the orientations, positional relationships, or dimensions expressed by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "up", "lower", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are orientations, positional relationships, or dimensions shown based on the accompanying drawings, and it should be understood that these terms do not indicate or imply that the devices or elements referred to must have a particular orientation and must be constructed and operated in a particular orientation, but are used merely for ease of description, and therefore should not be construed as limiting the scope of protection of the present disclosure.

[0058] In addition, the terms "first," "second," and "third" are for descriptive purposes only and should not be construed as indicating or implying a relative importance or numerical value of the technical features depicted. Thus, features defined by "first," "second," and "third" may explicitly or implicitly include one or more features. In the description of this disclosure, the term "plurality" means two or more, unless expressly and specifically specified otherwise.

[0059] In this disclosure, unless otherwise expressly stated or defined, terms such as "attached," "connected," "connected," and "fixed" should be interpreted broadly, for example, they may be a fixed connection, a detachable connection, or an integrated connection, may be a mechanical connection, or an electrical connection, or communication, and may be a direct connection, or an indirect connection using an intermediate medium, or an internal communication between two elements, or an interaction between two elements. Those skilled in the art may understand the specific meaning of the above terms in this disclosure according to the particular situation.

[0060] In this disclosure, unless expressly stated or limited otherwise, a first feature being "on" or "under" a second feature can include cases where the first feature is in direct contact with the second feature, and can also include cases where the first feature and the second feature are not in direct contact, but are in contact through another feature between them. Furthermore, a first feature being "over," "above," or "on" a second feature can include cases where the first feature is directly or diagonally above the second feature, or simply indicates that the first feature is higher than the second feature. A first feature being "below," "under," or "beneath" a second feature can include cases where the first feature is directly or diagonally below the second feature, or simply indicates that the first feature is lower than the second feature.

[0061] This description shows many different implementations or examples that can be used to implement the present disclosure. It should be understood that these different implementations or examples are merely illustrative and do not limit the scope of protection of the present disclosure in any way. Based on the disclosure of the description of the present disclosure, a person skilled in the art will think of various modifications or replacements. All these modifications or replacements shall be encompassed in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be subject to the scope of protection of the patent claims.

Claims

1. 1. A spot size converter comprising: a first end face configured to be coupled to an integrated optical waveguide; and a second end face parallel to the first end face and configured to be coupled to an optical fiber, A substrate; an insulating layer located on a side of the substrate and having an orthogonal projection onto the substrate that substantially coincides with the substrate; a first waveguide located on a side of the insulating layer remote from the substrate, a flat layer including a first wide end portion extending to the first end surface and a first narrow end portion extending to or at a distance from the second end surface, the flat layer having a width in a width direction that decreases at a gradient from the first wide end portion to the first narrow end portion and including a first equal width portion adjacent the first narrow end portion, the width direction being parallel to the substrate and parallel to the first end surface; a raised layer stacked on a side of the planar layer away from the substrate, the raised layer including a second wide end extending to the first edge and a second narrow end at a distance from the first narrow end, the raised layer having a gradient decreasing width from the second wide end to the second narrow end and including a second equal width portion adjacent the second narrow end; a first waveguide including: a covering layer located on a side of the first waveguide remote from the substrate, extending to the second end face and covering at least one end of the second equal-width portion remote from the second end face, wherein a portion of the covering layer close to the second end face and a portion of the insulating layer close to the second end face form a second waveguide; Equipped with the flat layer includes the first equal width portion, a first gradually diverging portion, a third equal width portion, a second gradually diverging portion, and a fourth equal width portion, arranged in sequence in a direction away from the first narrow end, the raised layer includes the second equal-width portion, a third gradually diverging portion, and a fifth equal-width portion, arranged in sequence in a direction away from the second narrow end; each of the first gradually diverging portion, the second gradually diverging portion, and the third gradually diverging portion has a width that gradually increases in a direction away from the second end surface; a spot size converter, wherein in the direction away from the second end face, the widths of the first diverging portion and the third diverging portion increase linearly and the width of the second diverging portion increases nonlinearly.

2. The spot size converter of claim 1 , wherein the cover layer extends over at least one end of the third diverging portion remote from the second end face.

3. The spot size converter of claim 2 , wherein an orthogonal projection of the coating layer onto the substrate is rectangular, and a width of the coating layer is greater than a width of the third equal width portion.

4. the cladding layer covers the entire first waveguide, the cladding layer having a width that increases at a gradient in the direction away from the second end face; 3. The spot size converter of claim 2, wherein the coating layer comprises a sixth equal-width portion, a fourth gradually diverging portion, and a seventh equal-width portion arranged sequentially in the direction away from the second end face, the fourth gradually diverging portion having a width that gradually increases in the direction away from the second end face, and the sixth equal-width portion having a width greater than a width of the third equal-width portion.

5. the cladding layer covers the entire first waveguide, the cladding layer having a width that increases at a gradient in the direction away from the second end face; 3. The spot size converter of claim 2, wherein the coating layer includes a sixth equal width portion and a seventh equal width portion arranged sequentially in the direction away from the second end face, the sixth equal width portion having a width greater than a width of the third equal width portion.

6. the covering layer includes an eighth equal-width portion, a tapered portion, and a ninth equal-width portion, which are sequentially arranged in the direction away from the second end surface; the tapered portion has a width that gradually decreases in the direction away from the second end surface; The spot size converter of claim 2 , wherein the ninth equal width portion has a width greater than a width of the third equal width portion.

7. 7. The spot size converter of claim 6, wherein the coating layer covers the entire first waveguide, the coating layer further comprising a tenth portion located on a side of the ninth equal width portion away from the second end face, the tenth portion having a width greater than a width of the ninth equal width portion.

8. the spot size converter further includes a first side and a second side disposed parallel to each other and intersecting the first end face and the second end face; The spot size converter of claim 1 , wherein the fourth equal width portion extends to the first side and the second side.

9. The spot size converter of claim 1 , wherein a width of an upper end of the first narrow end is less than or equal to 400 nanometers.

10. The spot size converter of claim 1 , wherein a width of the coating layer at the second end face is greater than or equal to 1 micron and less than or equal to 20 microns.

11. The spot size converter of claim 1 , wherein the first equal width portion is prismatic and has a triangular or trapezoidal cross section parallel to the first end face.

12. The spot size converter of claim 1 , wherein the second equal width portion is prismatic and has a triangular or trapezoidal cross section parallel to the first end face.

13. the first end face is an input end of the spot size converter and the second end face is an output end of the spot size converter; or The spot size converter of claim 1 , wherein the second end face is an input end of the spot size converter and the first end face is an output end of the spot size converter.

14. A photonic device comprising the spot size converter according to claim 1.

Images