A spot size converter

Abstract

The present invention belongs to the field of integrated optical technology, and specifically relates to a spot size converter. The present invention includes a cladding and a silicon core; the cladding is arranged around the silicon core; along the propagation direction of the light beam, the silicon core includes an input end, a first adiabatic tapered waveguide, a second adiabatic tapered waveguide, a third adiabatic tapered waveguide, a fourth adiabatic tapered waveguide, a fifth adiabatic tapered waveguide, a sixth adiabatic tapered waveguide, a seventh adiabatic tapered waveguide, an eighth adiabatic tapered waveguide, a ninth adiabatic tapered waveguide, a tenth adiabatic tapered waveguide, an eleventh adiabatic tapered waveguide, a twelfth adiabatic tapered waveguide, a thirteenth adiabatic tapered waveguide, a fourteenth adiabatic tapered waveguide, a fifteenth adiabatic tapered waveguide, a sixteenth adiabatic tapered waveguide and an output end connected in sequence. The spot size converter of the present invention realizes the design of an ultra-compact device, and can be used for cascading between different functional units in a photonic integrated chip, so as to achieve a design goal of higher integration in the photonic integrated chip.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated optics, and in particular relates to a spot size converter. Background Art

[0002] Silicon-on-insulator (SOI) has become an important material for the study of passive photonic components due to its excellent light confinement and mature silicon processing technology. In complex photonic integrated chips, it is often necessary to use waveguides of different widths at the same time (for example, photonic lines are used in scenarios where single-mode is very important, while wider waveguides are used for connections or fiber coupling that require extremely low loss), as shown in the paper B. Luyssaert, P. Vandersteegen, D. Taillaert, P. Dumon, W. Bogaerts, P. Bienstman, D. Van Thourhout, V. Wiaux, S. Beckx, and R. Baets, "A compact photonic horizontal spot-size converter realized insilicon-on-insulator," IEEE Photon. Technol. Lett., vol. 17, no. 1, pp. 73-75, 2005.

[0003] To couple optical waveguides with different cross-sections and different modal sizes, smooth linear or parabolic tapered waveguides can be used, as shown in the paper CK Burns, AF Milton, and ABLee, "Optical-waveguide parabolic coupling horns," Appl. Phys. Lett., vol. 30, no. 1, pp. 28-30, 1977. However, in order to achieve adiabatic or lossless transmission, a sufficiently long device length is required. In complex photonic integrated chips, each component should occupy as little space as possible to reduce material, processing and packaging costs. Therefore, shorter innovative device designs are needed. Summary of the invention

[0004] The object of the present invention is to provide a spot size converter, aiming to design a spot size converter with small size, low loss, high transmission efficiency and simple structure.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0006] A spot size converter comprises a cladding and a silicon core; the cladding is arranged around the silicon core; along the propagation direction of the light beam, the silicon core comprises an input end, a first adiabatic tapered waveguide, a second adiabatic tapered waveguide, a third adiabatic tapered waveguide, a fourth adiabatic tapered waveguide, a fifth adiabatic tapered waveguide, a sixth adiabatic tapered waveguide, a seventh adiabatic tapered waveguide, an eighth adiabatic tapered waveguide, a ninth adiabatic tapered waveguide, a tenth adiabatic tapered waveguide, an eleventh adiabatic tapered waveguide, a twelfth adiabatic tapered waveguide, a thirteenth adiabatic tapered waveguide, a fourteenth adiabatic tapered waveguide, a fifteenth adiabatic tapered waveguide, a sixteenth adiabatic tapered waveguide and an output end which are connected in sequence.

[0007] As a further preferred technical solution of the present invention, the material of the cladding is SiO2, with a refractive index n SiO2 =1.445, width is W0, thickness is h0; silicon core refractive index n Si =3.455, thickness is h = 220nm; the width of the silicon core input end is W I =2μm, the width of the output end is W O =10μm; the length of the silicon core input end is L I =5μm, the length of the output end is L O =5μm; the wavelength of the incident light beam is 1.55μm; the width and height of the cladding satisfy: W0>W and h0>h.

[0008] As a further preferred technical solution of the present invention, the first adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the first adiabatic tapered waveguide are W1=2μm and W2=2.3μm, respectively, and the length L1=6578nm; the second adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the second adiabatic tapered waveguide are W2=2.3μm and W3=2.54μm, respectively, and the length L2=7530nm; the third adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the second adiabatic tapered waveguide are W2=2.3μm and W3=2.54μm, respectively, and the length L2=7530nm; The thermal tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the third adiabatic tapered waveguide are W3=2.54μm and W4=2.80μm, respectively, and the length L3=9132nm; the fourth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the fourth adiabatic tapered waveguide are W4=2.80μm and W5=3.10μm, respectively, and the length L4=11378nm; the fifth adiabatic tapered waveguide is an isosceles trapezoidal layout: the fifth adiabatic tapered waveguide is an isosceles trapezoidal layout The initial waveguide width and the terminal waveguide width of the tapered waveguide are W5=3.10μm and W6=3.40μm, respectively, and the length L5=13308nm; the sixth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial waveguide width and the terminal waveguide width of the sixth adiabatic tapered waveguide are W6=3.4μm and W7=3.76μm, respectively, and the length L6=16740nm; the seventh adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial waveguide width and the terminal waveguide width of the seventh adiabatic tapered waveguide are W6=3.4μm and W7=3.76μm, respectively, and the length L6=16740nm. The widths are W7=3.76μm and W8=4.18μm, respectively, and the length is L7=20976nm; the eighth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the eighth adiabatic tapered waveguide are W8=4.18μm and W9=4.60μm, respectively, and the length is L8=24700nm; the ninth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the ninth adiabatic tapered waveguide are W9=4.60μm and W10=4.60μm, respectively. 10 =5.10μm, length L9=30980nm; the tenth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the tenth adiabatic tapered waveguide are W 10 =5.10μm and W 11 =5.66μm, length L 10 =38420nm; the eleventh adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the eleventh adiabatic tapered waveguide are W 11 =5.66μm and W 12 =6.28μm, length L 11 =47160nm; the twelfth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the twelfth adiabatic tapered waveguide are W 12 =6.28μm and W13 =6.96μm, length L 12 =57740nm; the thirteenth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the thirteenth adiabatic tapered waveguide are W 13 =6.96μm and W 14 =7.62μm, length L 13 =66770nm; the fourteenth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the fourteenth adiabatic tapered waveguide are W 14 =7.62μm and W 15 =8.40μm, length L 14 =83020nm; the fifteenth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the fifteenth adiabatic tapered waveguide are W 15 =8.40μm and W 16 =9.20μm, length L 15 =97600nm; the sixteenth adiabatic tapered waveguide is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the sixteenth adiabatic tapered waveguide are W 16 =9.20μm and W 17 =10.0μm, length L 16 =111530nm.

[0009] Further as a preferred technical solution of the present invention, W0=12 μm and h0=1.22 μm.

[0010] The spot size converter described in the present invention, using the above technical solution, has the following technical effects compared with the prior art:

[0011] (1) The spot size converter of the present invention can realize the connection between two waveguides with very different widths (for example, the input waveguide width of the present invention is only 2 μm, while the output waveguide width reaches 10 μm), thereby realizing lossless transmission of the mode. When the light beam mode is emitted at the input end, although the width of the waveguide changes greatly during the energy transmission process, all the energy remains in the excited mode, that is, when the mode propagates in the spot size converter of the present invention, neither mode interference nor mode conversion occurs.

[0012] (2) The design of the present invention is much better than the traditional linear connection scheme in terms of efficiency. When achieving a power transmission efficiency of 98%, the present invention only requires a length of 57 μm, while the traditional linear connection scheme requires a length of 126 μm, which is 2.2 times that of the present invention. The present invention greatly reduces the device size of the spot size converter and can achieve miniaturization design in photonic integrated chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a cross-sectional schematic diagram of a spot size converter of the present invention;

[0014] Figure 2 A schematic diagram of a conventional linear connection for spot size conversion of the present invention;

[0015] Figure 3 The connection method of the silicon core in the spot size converter of the present invention;

[0016] Figure 4 A comparison diagram of the power transmission efficiency curves of the present invention and the traditional straight line connection design;

[0017] Wherein, the figure markings are: 1, cladding; 2, silicon core; 3, first adiabatic tapered waveguide; 4, second adiabatic tapered waveguide; 5, third adiabatic tapered waveguide; 6, fourth adiabatic tapered waveguide; 7, fifth adiabatic tapered waveguide; 8, sixth adiabatic tapered waveguide; 9, seventh adiabatic tapered waveguide; 10, eighth adiabatic tapered waveguide; 11, ninth adiabatic tapered waveguide; 12, tenth adiabatic tapered waveguide; 13, eleventh adiabatic tapered waveguide; 14, twelfth adiabatic tapered waveguide; 15, thirteenth adiabatic tapered waveguide; 16, fourteenth adiabatic tapered waveguide; 17, fifteenth adiabatic tapered waveguide; 18, sixteenth adiabatic tapered waveguide. DETAILED DESCRIPTION

[0018] The present invention is further explained below in detail with reference to the accompanying drawings so that those skilled in the art can more deeply understand the present invention and be able to implement it. However, the following reference examples are only used to explain the present invention and are not intended to limit the present invention.

[0019] like Figure 1-2 As shown, a spot size converter comprises a cladding 1 and a silicon core 2; the cladding 1 is arranged around the silicon core 2; along the propagation direction of the light beam, the silicon core 2 comprises an input end, a first adiabatic tapered waveguide 3, a second adiabatic tapered waveguide 4, a third adiabatic tapered waveguide 5, a fourth adiabatic tapered waveguide 6, a fifth adiabatic tapered waveguide 7, a sixth adiabatic tapered waveguide 8, a seventh adiabatic tapered waveguide 9, an eighth adiabatic tapered waveguide 10, a ninth adiabatic tapered waveguide 11, a tenth adiabatic tapered waveguide 12, an eleventh adiabatic tapered waveguide 13, a twelfth adiabatic tapered waveguide 14, a thirteenth adiabatic tapered waveguide 15, a fourteenth adiabatic tapered waveguide 16, a fifteenth adiabatic tapered waveguide 17, a sixteenth adiabatic tapered waveguide 18 and an output end which are connected in sequence.

[0020] The material of cladding 1 is SiO2, with a refractive index of n SiO2 =1.445, width is W0, thickness is h0; refractive index of silicon core 2 is n Si=3.455, thickness is h = 220nm; the width of the input end of silicon core 2 is W I =2μm, the width of the output end is W O =10μm; the length of the input end of silicon core 2 is L I =5μm, the length of the output end is L O =5μm; the wavelength of the incident light beam is 1.55μm; the width and height of the cladding 1 satisfy: W0>W and h0>h. In the embodiment of the present invention, W0=12μm and h0=1.220μm are set respectively.

[0021] like Figure 3 As shown, the first adiabatic tapered waveguide 3 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the first adiabatic tapered waveguide 3 are W1=2μm and W2=2.3μm respectively, and the length L1=6578nm; the second adiabatic tapered waveguide 4 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the second adiabatic tapered waveguide 4 are W2=2.3μm and W3=2.54μm respectively, and the length L2=7530nm; the third adiabatic tapered waveguide 5 is an isosceles trapezoidal layout: The initial waveguide width and the terminal waveguide width of the third adiabatic tapered waveguide 5 are W3=2.54μm and W4=2.80μm, respectively, and the length L3=9132nm; the fourth adiabatic tapered waveguide 6 is an isosceles trapezoidal layout: the initial waveguide width and the terminal waveguide width of the fourth adiabatic tapered waveguide 6 are W4=2.80μm and W5=3.10μm, respectively, and the length L4=11378nm; the fifth adiabatic tapered waveguide 7 is an isosceles trapezoidal layout: the initial waveguide width and the terminal waveguide width of the fifth adiabatic tapered waveguide 7 are W4=2.80μm and W5=3.10μm, respectively, and the length L4=11378nm. The width and end waveguide width of the sixth adiabatic tapered waveguide 8 are W5=3.10μm and W6=3.40μm, respectively, and the length L5=13308nm; the sixth adiabatic tapered waveguide 8 is an isosceles trapezoidal layout: the initial end waveguide width and the end waveguide width of the sixth adiabatic tapered waveguide 8 are W6=3.4μm and W7=3.76μm, respectively, and the length L6=16740nm; the seventh adiabatic tapered waveguide 9 is an isosceles trapezoidal layout: the initial end waveguide width and the end waveguide width of the seventh adiabatic tapered waveguide 9 are W7=3.4μm and W7=3.76μm, respectively, and the length L6=16740nm. =3.76μm and W8=4.18μm, length L7=20976nm; the eighth adiabatic tapered waveguide 10 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the eighth adiabatic tapered waveguide 10 are W8=4.18μm and W9=4.60μm, respectively, and the length L8=24700nm; the ninth adiabatic tapered waveguide 11 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal waveguide width of the ninth adiabatic tapered waveguide 11 are W9=4.60μm and W9=4.60μm, respectively. 10 =5.10μm, length L9=30980nm; the tenth adiabatic tapered waveguide 12 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the tenth adiabatic tapered waveguide 12 are W 10 =5.10μm and W11 =5.66μm, length L 10 =38420nm; the eleventh adiabatic tapered waveguide 13 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the eleventh adiabatic tapered waveguide 13 are W 11 =5.66μm and W 12 =6.28μm, length L 11 =47160nm; the twelfth adiabatic tapered waveguide 14 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the twelfth adiabatic tapered waveguide 14 are W 12 =6.28μm and W 13 =6.96μm, length L 12 =57740nm; the thirteenth adiabatic tapered waveguide 15 is an isosceles trapezoidal layout: the thirteenth adiabatic tapered waveguide 15 initial end waveguide width and terminal waveguide width are W 13 =6.96μm and W 14 =7.62μm, length L 13 =66770nm; the fourteenth adiabatic tapered waveguide 16 is an isosceles trapezoidal layout: the fourteenth adiabatic tapered waveguide 16 initial end waveguide width and terminal waveguide width are W 14 =7.62μm and W 15 =8.40μm, length L 14 =83020nm; the fifteenth adiabatic tapered waveguide 17 is an isosceles trapezoidal layout: the fifteenth adiabatic tapered waveguide 17 initial end waveguide width and terminal waveguide width are W 15 =8.40μm and W 16 =9.20μm, length L 15 =97600nm; the sixteenth adiabatic tapered waveguide 18 is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the sixteenth adiabatic tapered waveguide 18 are W 16 =9.20μm and W 17 =10.0μm, length L 16 =111530nm.

[0022] Through the above layout, for TE mode or TM mode, in the spot size converter of the present invention, when the light beam mode is emitted at the input end, although the width of the waveguide changes greatly during the energy transmission process, all the energy stays in the excited mode, that is, when the mode propagates in the spot size converter of the present invention, neither mode interference nor mode conversion occurs.

[0023] The transmission efficiency of the spot size conversion designed by the present invention is as follows: Figure 4As shown in the figure, when a transmission efficiency of 98% is to be achieved, the solution of the present invention only requires a length of 57 μm, while the traditional linear connection solution requires a length of 126 μm, which is 2.2 times that of the solution of the present invention. Therefore, the spot size converter proposed in the present invention realizes the design of an ultra-compact device, which can be used for cascading between different functional units in a photonic integrated chip, achieving the design goal of a higher degree of integration in a photonic integrated chip.

[0024] The specific implementation scheme described above further describes in detail the purpose, technical scheme and beneficial effects of the present invention. It should be understood that the above is only a specific implementation scheme of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any technician in the field without departing from the concept and principle of the present invention should fall within the scope of protection of the present invention.

Claims

1. A spot size converter, characterized in that: The invention comprises a cladding (1) and a silicon core (2); the cladding (1) is arranged around the silicon core (2); along the propagation direction of the light beam, the silicon core (2) comprises an input end, a first adiabatic tapered waveguide (3), a second adiabatic tapered waveguide (4), a third adiabatic tapered waveguide (5), a fourth adiabatic tapered waveguide (6), a fifth adiabatic tapered waveguide (7), a sixth adiabatic tapered waveguide (8), a seventh adiabatic tapered waveguide (9), an eighth adiabatic tapered waveguide (10), a ninth adiabatic tapered waveguide (11), and a A tapered waveguide (11), a tenth adiabatic tapered waveguide (12), an eleventh adiabatic tapered waveguide (13), a twelfth adiabatic tapered waveguide (14), a thirteenth adiabatic tapered waveguide (15), a fourteenth adiabatic tapered waveguide (16), a fifteenth adiabatic tapered waveguide (17), a sixteenth adiabatic tapered waveguide (18) and an output end; the first adiabatic tapered waveguide (3) is an isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the first adiabatic tapered waveguide (3) are respectively W 1 = 2 m m and W 2 = 2.3 m m, length L 1 = 6578 nm; The second adiabatic tapered waveguide (4) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the second adiabatic tapered waveguide (4) are respectively W 2 = 2.3 m m and W 3 = 2.54 m m, length L 2 = 7530 nm; The third adiabatic tapered waveguide (5) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the third adiabatic tapered waveguide (5) are respectively W 3 = 2.54 m m and W 4 = 2.80 m m, length L 3 = 9132 nm; The fourth adiabatic tapered waveguide (6) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the fourth adiabatic tapered waveguide (6) are respectively W 4 = 2.80 m m and W 5 = 3.10 m m, length L 4 = 11378 nm; The fifth adiabatic tapered waveguide (7) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the fifth adiabatic tapered waveguide (7) are respectively W 5 = 3.10 m m and W 6 = 3.40 m m, length L 5 = 13308 nm; The sixth adiabatic tapered waveguide (8) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the sixth adiabatic tapered waveguide (8) are respectively W 6 = 3.4 m m and W 7 = 3.76 m m, length L 6 = 16740 nm; The seventh adiabatic tapered waveguide (9) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the seventh adiabatic tapered waveguide (9) are respectively W 7 = 3.76 m m and W 8 = 4.18 m m, length L 7 = 20976 nm; The eighth adiabatic tapered waveguide (10) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the eighth adiabatic tapered waveguide (10) are respectively W 8 = 4.18 m m and W 9 = 4.60 m m, length L 8 = 24700 nm; The ninth adiabatic tapered waveguide (11) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the ninth adiabatic tapered waveguide (11) are respectively W 9 = 4.60 m m and W 10 =5.10 m m, length L 9 = 30980 nm; The tenth adiabatic tapered waveguide (12) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the tenth adiabatic tapered waveguide (12) are respectively W 10 = 5.10 m m and W 11 = 5.66 m m, length L 10 = 38420 nm; The eleventh adiabatic tapered waveguide (13) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the eleventh adiabatic tapered waveguide (13) are respectively W 11 = 5.66 m m and W 12 = 6.28 m m, length L 11 = 47160 nm; The twelfth adiabatic tapered waveguide (14) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the twelfth adiabatic tapered waveguide (14) are respectively W 12 = 6.28 m m and W 13 = 6.96 m m, length L 12 = 57740 nm; The thirteenth adiabatic tapered waveguide (15) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the thirteenth adiabatic tapered waveguide (15) are respectively W 13 = 6.96 m m and W 14 = 7.62 m m, length L 13 = 66770 nm; The fourteenth adiabatic tapered waveguide (16) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the fourteenth adiabatic tapered waveguide (16) are respectively W 14 = 7.62 m m and W 15 = 8.40 m m, length L 14 = 83020 nm; The fifteenth adiabatic tapered waveguide (17) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the fifteenth adiabatic tapered waveguide (17) are respectively W 15 = 8.40 m m and W 16 = 9.20 m m, length L 15 = 97600 nm; The sixteenth adiabatic tapered waveguide (18) is of isosceles trapezoidal layout: the initial end waveguide width and the terminal end waveguide width of the sixteenth adiabatic tapered waveguide (18) are respectively W 16 = 9.20 m m and W 17 = 10.0 m m, length L 16 = 111530 nm.

2. A spot size converter according to claim 1, characterized in that: The material of the cladding (1) is SiO2, with a refractive index of n SiO2 = 1.445, width is W 0, thickness is h 0; silicon core (2) refractive index n Si = 3.455, thickness is h = 220nm; the width of the input end of the silicon core (2) is W I = 2 m m, the width of the output end is W O = 10 m m; the length of the input end of the silicon core (2) is L I = 5 m m, the length of the output end is L O = 5 m m; the wavelength of the incident beam is 1.55 m m; the width and height of the cladding (1) satisfy: W 0 > W and h 0 > h .

3. A spot size converter according to claim 2, characterized in that: W 0 = 12 m m and h 0 = 1.22 m m.

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