phase shifter

Abstract

The phase shifter of the present application includes a first waveguide for transmitting an optical signal; a second waveguide for transmitting an optical signal, which is arranged in parallel with the first waveguide; a first U-shaped waveguide for transmitting an optical signal, one end of which is connected to one end of the first waveguide and the other end of which is connected to one end of the second waveguide; a first heating electrode, which is arranged in parallel with the first waveguide; a second heating electrode, which is arranged in parallel with the first waveguide; a third heating electrode, which is arranged in parallel with the first waveguide; and a substrate, on which the first waveguide, the second waveguide, the first U-shaped waveguide, the first heating electrode, the second heating electrode, and the third heating electrode are formed, the first waveguide being located between the first heating electrode and the second heating electrode, and the second waveguide being located between the second heating electrode and the third heating electrode.

Description

Technical Field

[0001] This invention relates to a phase shifter, and more particularly to a silicon photothermal phase shifter. Background Technology

[0002] Currently, silicon-based optoelectronic technology is widely used in optical communication, lidar, sensors, and other fields. On-chip thermally modulated phase shifters based on silicon photonics technology can provide flexible phase manipulation methods in integrated optical circuits. Compared with discrete phase shifters, silicon photonic thermally modulated phase shifters have advantages such as small size, low cost, and mass production capability. Currently, two methods are commonly used to realize silicon photonic thermally modulated phase shifters. One method involves doping pure silicon on both sides of a waveguide with pentavalent elements (such as P, As, etc.) or trivalent elements (such as B, Ga, etc.) to obtain N-type or P-type silicon as doped silicon. Applying a voltage to the doped silicon on both sides of the waveguide generates Joule heating, thereby heating the waveguide to achieve thermo-optical phase shift. The second method involves placing a TiN (titanium nitride)-based heating electrode above the waveguide. Applying electricity to the TiN generates Joule heating, which in turn affects the refractive index of the waveguide below.

[0003] Figure 1a This is a cross-sectional view showing a thermally modulated phase shifter with doped silicon. (Example) Figure 1a As shown, light propagates in a direction perpendicular to the cross-sectional view. The ridge waveguide structure restricts the light's propagation path. The silicon semiconductor on both sides of the ridge waveguide is transformed into a silicon resistor with low resistivity through n++ or p++ doping. When an electric field is applied to the silicon resistor in a direction perpendicular to the cross-sectional view, current flows through the silicon resistor in the same direction, generating Joule heating. The resulting thermal field alters the refractive index of the material in the ridge waveguide, and this change in refractive index, in turn, alters the phase of the light field in the ridge waveguide, achieving a phase shift.

[0004] Figure 1b This is a cross-sectional view showing a thermally modulated phase shifter with TiN. (See diagram below.) Figure 1b As shown, by applying an electric field to the TiN resistor in a direction perpendicular to the cross-section, current flows through the TiN resistor in the same direction, generating Joule heating. The resulting thermal field alters the refractive index of the underlying waveguide material, which in turn changes the phase of the optical field in the waveguide, achieving a phase shift. From a process complexity perspective, silicon doping technology, besides being applied to thermally tunable phase shifters, is widely used in modulators, detectors, tunable attenuators, and other devices. During fabrication, it can reuse the same photomask as other doped devices without incurring additional costs. In contrast, the fabrication of TiN thermally tunable phase shifters involves the growth of TiN material, requiring a separate photomask, and TiN material is primarily used only in thermally tunable phase shifters. Compared to silicon-doped solutions, TiN thermally tunable phase shifters have disadvantages in terms of cost and process complexity. Summary of the Invention

[0005] The technical problem that the invention aims to solve

[0006] Both silicon-doped and TiN-doped thermally modulated phase shifters suffer from excessive power consumption under current technology. Specifically, both silicon-doped and TiN-doped thermally modulated phase shifters typically employ a single straight waveguide structure. Figure 2a This is a schematic diagram illustrating the structure of a thermally modulated phase shifter with a straight waveguide doped silicon, as described in the prior art. Figure 2b This is a schematic diagram illustrating the structure of a thermally modulated phase shifter with a straight waveguide TiN as described in the prior art. Figure 2a , Figure 2b As shown. Without employing other thermal isolation methods (e.g., adding thermal isolation trenches based on deep silicon etching), the thermal tuning efficiency achievable by a straight waveguide structure thermally tuned phase shifter, while less than 20 mW / π, is difficult to reach less than 10 mW / π, as the distance between the doped silicon or TiN and the silicon waveguide is adjusted to reduce optical transmission loss and improve thermal tuning efficiency.

[0007] Purpose of the invention

[0008] This invention was made to solve the above-mentioned problems, and its purpose is to provide a phase shifter that can greatly reduce overall power consumption.

[0009] Technical solutions to solve technical problems

[0010] A first aspect of the present invention provides a phase shifter, characterized in that it comprises:

[0011] The first waveguide is used to transmit optical signals;

[0012] A second waveguide, which is arranged parallel to the first waveguide, is used to transmit optical signals;

[0013] A first U-shaped waveguide, one end of which is connected to one end of the first waveguide and the other end of which is connected to one end of the second waveguide, is used to transmit optical signals;

[0014] A first heating electrode is disposed parallel to the first waveguide;

[0015] A second heating electrode is disposed parallel to the first waveguide;

[0016] A third heating electrode, which is disposed parallel to the first waveguide; and

[0017] Substrate,

[0018] The first waveguide, the second waveguide, the first U-shaped waveguide, the first heating electrode, the second heating electrode, and the third heating electrode are formed on the substrate.

[0019] The first waveguide is located between the first heating electrode and the second heating electrode.

[0020] The second waveguide is located between the second heating electrode and the third heating electrode.

[0021] The phase shifter of the second aspect of the present invention is characterized in that,

[0022] The top of the first waveguide is separated from the top of the first heating electrode and the top of the second heating electrode by a predetermined distance.

[0023] The top of the second waveguide is separated from the top of the second heating electrode and the top of the third heating electrode by a specified distance.

[0024] The phase shifter of the third aspect of the present invention is characterized in that,

[0025] The first waveguide, the second waveguide, and the first U-shaped waveguide are made of silicon material.

[0026] The first heating electrode, the second heating electrode, and the third heating electrode are resistors made of silicon material doped with n++ or p++.

[0027] The phase shifter of the fourth aspect of the present invention is characterized in that,

[0028] One end of the top of the first heating electrode is connected to the cathode, and the other end of the top of the first heating electrode is connected to the anode.

[0029] One end of the top of the second heating electrode is connected to the cathode, and the other end of the top of the second heating electrode is connected to the anode.

[0030] One end of the top of the third heating electrode is connected to the cathode, and the other end of the top of the third heating electrode is connected to the anode.

[0031] The phase shifter of the fifth aspect of the present invention is characterized in that it further comprises:

[0032] A third waveguide, which is disposed parallel to the first waveguide on the substrate, is used to transmit optical signals;

[0033] A second U-shaped waveguide, disposed on the substrate, has one end connected to the other end of the second waveguide and the other end connected to one end of the third waveguide. This second U-shaped waveguide is used to transmit optical signals.

[0034] A fourth heating electrode is disposed on the substrate parallel to the first waveguide.

[0035] The third waveguide is located between the third heating electrode and the fourth heating electrode.

[0036] The phase shifter of the sixth aspect of the present invention is characterized in that it further comprises:

[0037] The top of the third waveguide is separated from the top of the third heating electrode and the top of the fourth heating electrode by a specified distance.

[0038] The phase shifter of the seventh aspect of the present invention is characterized in that,

[0039] The third waveguide and the second U-shaped waveguide are made of silicon.

[0040] The fourth heating electrode is a resistor made of silicon material doped with n++ or p++.

[0041] The phase shifter of the eighth aspect of the present invention is characterized in that,

[0042] One end of the top of the fourth heating electrode is connected to the cathode, and the other end of the top of the fourth heating electrode is connected to the anode.

[0043] The phase shifter of the ninth aspect of the present invention is characterized in that,

[0044] It also includes: a fifth heating electrode, which is disposed parallel to the first waveguide and on the first waveguide; and

[0045] A sixth heating electrode is disposed parallel to the first waveguide and is disposed on the second waveguide.

[0046] The phase shifter of the tenth aspect of the present invention is characterized in that,

[0047] One end of the top of the fifth heating electrode is connected to the cathode, and the other end of the top of the fifth heating electrode is connected to the anode.

[0048] One end of the top of the sixth heating electrode is connected to the cathode, and the other end of the top of the sixth heating electrode is connected to the anode.

[0049] The phase shifter of the eleventh aspect of the present invention is characterized in that,

[0050] The fifth and sixth heating electrodes are made of TiN or tungsten.

[0051] Invention Effects

[0052] According to the phase shifter of the present invention, by increasing the number of heating electrodes and arranging the heating electrodes and optical waveguides in an interlaced manner, the thermal energy of the heating electrodes between adjacent optical waveguides can be utilized by the two optical waveguides, thereby improving the thermal energy utilization rate and significantly enhancing the thermal tuning efficiency. Attached Figure Description

[0053] Figure 1a This is a cross-sectional view showing a thermally modulated phase shifter with doped silicon.

[0054] Figure 1b This is a cross-sectional view showing a thermally modulated phase shifter with TiN.

[0055] Figure 2a This is a schematic diagram illustrating the structure of a thermally modulated phase shifter with a straight waveguide doped silicon, as described in the prior art.

[0056] Figure 2b This is a schematic diagram illustrating the structure of a thermally modulated phase shifter with a straight waveguide TiN as described in the prior art.

[0058] Figure 3 This is a three-dimensional schematic diagram showing the structure of a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 1 of the present invention.

[0059] Figure 4a This is a side view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 1 of the present invention.

[0060] Figure 4b This is a top view showing a thermally adjustable phase shifter with multiple heating electrodes according to Embodiment 1 of the present invention.

[0061] Figure 5 This is a schematic diagram illustrating the relationship between relative phase shift and total power consumption in Embodiment 1 of the present invention.

[0062] Figure 6a This is a side view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 2 of the present invention.

[0063] Figure 6b This is a top view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 2 of the present invention.

[0064] Figure 7a This is a side view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 3 of the present invention.

[0065] Figure 7b This is a top view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 3 of the present invention.

[0066] Label Explanation

[0067] 10 First Phase Shifter

[0068] 20 Second Phase Shifter

[0069] 30 Third Phase Shifter

[0070] 100 substrate

[0071] 101 Connector

[0072] 102 First Direct Waveguide

[0073] 104 Second Straight Waveguide

[0074] 106 First U-shaped waveguide

[0075] 108 First Resistor

[0076] 110 Second Resistor

[0077] 112 Third Resistor

[0078] 114 Cathode

[0079] 116 Anode

[0080] 118 Third Straight Waveguide

[0081] 120 fourth resistor

[0082] 122 Second U-shaped waveguide

[0083] 130 Fifth heating electrode

[0084] 132 Sixth heating electrode Detailed Implementation

[0085] <Structure of the optical computing system of the present invention>

[0086] Example 1

[0087] Figure 3 This is a three-dimensional schematic diagram showing the structure of a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 1 of the present invention. Figure 4a This is a side view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 1 of the present invention. Figure 4b This is a top view showing a thermally adjustable phase shifter with multiple heating electrodes according to Embodiment 1 of the present invention. Referring below... Figure 3 , Figure 4a , Figure 4b The detailed structure of the phase shifter in Embodiment 1 of the present invention will be described below.

[0088] like Figure 3, Figure 4a , Figure 4b As shown, the first phase shifter 10 according to Embodiment 1 of the present invention includes: a substrate 100, a plurality of connectors 101, a first straight waveguide 102, a second straight waveguide 104, a first U-shaped waveguide 106, a first resistor 108, a second resistor 110, a third resistor 112, a cathode 114, and an anode 116. The plurality of connectors 101, the first straight waveguide 102, the second straight waveguide 104, the first U-shaped waveguide 106, the first resistor 108, the second resistor 110, and the third resistor 112 are formed on the substrate 100 made of silicon material. The first resistor 108, the second resistor 110, and the third resistor 112 are respectively made of silicon material doped with n++ or p++, and are respectively positioned along the direction of light transmission, i.e., the x-direction (…). Figure 4b It extends in a straight line in the horizontal direction.

[0089] Figure 4b In the middle, the first direct waveguide 102 is made of silicon material, along the direction of light transmission, i.e., the x-direction ( Figure 4b It extends in a straight line in the horizontal direction and is located between the first resistor 108 and the second resistor 110.

[0090] The second straight waveguide 104 is made of silicon material, extends in a straight line along the x-direction, and is located between the third resistor 112 and the second resistor 110.

[0091] The first resistor 108, the first straight waveguide 102, the second resistor 110, the second straight waveguide 104, and the third resistor 112 are arranged sequentially along the y-axis.

[0092] In the y direction ( Figure 4b In the vertical direction, there is a distance D between the first resistor 108 and the first straight waveguide 102, a distance D between the first straight waveguide 102 and the second resistor 110, a distance D between the second resistor 110 and the second straight waveguide 104, and a distance D between the second straight waveguide 104 and the third resistor 112. Here, the distance D is equal to 1 micrometer.

[0093] The first straight waveguide 102, the second straight waveguide 104, the first resistor 108, the second resistor 110, and the third resistor 112 have the same length L. Here, the length L is equal to 100 μm.

[0094] like Figure 4aAs shown, the first straight waveguide 102, the second straight waveguide 104, the first U-shaped waveguide 106, the first resistor 108, the second resistor 110, the third resistor 112, and the first U-shaped waveguide 106 all have the same height H. A plurality of connectors 101, made of silicon, extend in a planar shape parallel to the substrate 100 and are respectively connected between the bottom of the first resistor 108 and the bottom of the first straight waveguide 102, between the bottom of the first straight waveguide 102 and the bottom of the second resistor 110, between the bottom of the second resistor 110 and the bottom of the second straight waveguide 104, and between the bottom of the second straight waveguide 104 and the bottom of the third resistor 112. The plurality of connectors 101 have the same height h, and the height h of the plurality of connectors 101 is less than the height H.

[0095] Figure 4b In the first resistor 108, one end of the top in the x direction is connected to the cathode 114, and the other end of the top in the x direction is connected to the anode 116.

[0096] The top of the second resistor 110 is connected to the cathode 114 in the x direction, and the other end of the top of the second resistor 110 in the x direction is connected to the anode 116.

[0097] The top of the third resistor 112 is connected to the cathode 114 in the x direction, and the other end of the top of the third resistor 112 in the x direction is connected to the anode 116.

[0098] Figure 4b In the first U-shaped waveguide 106, one end is connected to the end of the first straight waveguide 102 near the anode 116 in the x direction, and the other end of the first U-shaped waveguide 106 is connected to the end of the second straight waveguide 104 near the anode 116 in the x direction.

[0099] Example 1 has a structure with two straight waveguides, one U-shaped waveguide, and three heating electrodes, as shown below. Figure 3 , Figure 4a , Figure 4b As shown, compared to the conventional structure with one straight waveguide and two heating electrodes, in this embodiment 1, the total length of the multiple straight waveguides is equal to the length of the original single straight waveguide, and the total length of the multiple heating electrodes is equal to the total length of the original heating electrodes. Furthermore, the silicon resistors serving as heating electrodes and the optical waveguides are interleaved, with the middle silicon resistor sandwiched between two waveguides, to accumulate the phase change of the light transmitted in the waveguides. Therefore, the path length of light traveling through one straight waveguide in a conventional phase shifter is equal to the path length of light traveling through multiple straight waveguides in the phase shifter of this embodiment 1.

[0100] When the resistor generates heat that affects the refractive index of the optical waveguide, the magnitude of the cumulative phase of light propagating in the optical waveguide with the changed refractive index also changes. This makes the phase change of light in a conventional phase shifter in one straight waveguide equal to the cumulative phase change of light in multiple straight waveguides in the phase shifter of this embodiment 1. Therefore, the optical path of a conventional phase shifter with two heating electrodes and one straight waveguide can be replaced with the optical path of this invention with a series structure of three or more heating electrodes, two or more straight waveguides, and one or more U-shaped waveguides.

[0101] Therefore, in this embodiment 1, the silicon resistor located in the middle is sandwiched between two straight waveguides. Through this structure, except for the two outermost silicon resistors on the left and right, the heat generated by the remaining N-2 (N is the number of resistors, N≥3) silicon resistors located in the middle can be utilized by the adjacent straight waveguides. Compared with the previous phase shifter scheme, the heat utilization efficiency of the resistor is improved, thereby improving the thermal tuning efficiency of the thermal phase shifter.

[0102] Figure 5 This is a schematic diagram illustrating the relationship between relative phase shift and total power consumption in Embodiment 1 of the present invention. Figure 5 In the diagram, the solid line represents the relationship between the thermal tuning efficiency (i.e., the phase change of light) and the total power consumption of the phase shifter with two straight waveguides, one U-shaped waveguide, and three resistors in this embodiment. The dashed line represents the relationship between the thermal tuning efficiency (i.e., the phase change of light) and the total power consumption of the phase shifter with one waveguide and two resistors in the conventional embodiment.

[0103] Figure 5 The diagram illustrates the relative phase change as a function of the total power consumption applied to the heating electrode, i.e., the thermal tuning efficiency, when transmitting 1550nm light in a conventional phase shifter with one 200µm long straight waveguide and two resistors; and the thermal tuning efficiency when transmitting 1550nm light in phase shifters of this embodiment 1 with two 100µm long straight waveguides, one U-shaped waveguide, and three resistors, respectively. According to... Figure 5 It is known that in conventional phase shifters with one 200µm long straight waveguide and two resistors, the total power consumption required when the relative phase shift of light is π is 14.2mW. In contrast, in the phase shifter of this embodiment 1 with two 100µm long straight waveguides, one U-shaped waveguide, and three 100µm long resistors, the total power consumption required when the relative phase shift of light is π is 6.8mW.

[0104] Therefore, it can be seen that, compared with the conventional phase shifter, the phase shifter of this embodiment 1 can significantly improve the thermal tuning efficiency and greatly reduce the total power consumption when changing the phase of light by thermal modulation.

[0105] This is because: In conventional thermally modulated phase shifters, straight waveguides typically contain only two heating electrodes, left and right. Since the diffusion of the thermal field is not directional, the heat from the two heating electrodes, except for the heat required to provide the waveguide with a temperature rise, is dissipated into the cladding. Therefore, the thermal efficiency of conventional thermally modulated phase shifters is often less than or equal to 50%.

[0106] In Embodiment 1 of the present invention, the number of heating electrodes is increased and the optical waveguide routing is optimized, resulting in 3 heating electrodes, 2 straight waveguides, and 1 U-shaped waveguide. By increasing the number of heating electrodes and waveguides and arranging them in an interlaced manner, and by rationally designing the number and length of the heating electrodes and waveguides, as well as their relative positions, the heat energy of the heating electrode located between the two optical waveguides can be utilized by the two adjacent optical waveguides. This results in an average heat energy utilization rate of the heating electrodes = (heat energy utilization rate of the left heating electrode + heat energy utilization rate of the middle heating electrode + heat energy utilization rate of the right heating electrode) / 3 = (50% + 100% + 50%) / 3 = 66.7%. Compared with conventional thermally modulated phase shifters, this increases the heat energy utilization rate of the thermally modulated phase shifter by 16.7% (66.7% - 50% = 16.7%), significantly improving the average heat energy utilization rate and thus significantly improving the thermal modulation efficiency of the thermally modulated phase shifter. The thermal modulation efficiency of Embodiment 1 is less than 10mW / π.

[0107] Example 2

[0108] Figure 6a This is a side view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 2 of the present invention. Figure 6b This is a top view showing a thermally adjustable phase shifter with multiple heating electrodes according to Embodiment 2 of the present invention. Refer to the following... Figure 6a , Figure 6b The detailed structure of the phase shifter in Embodiment 2 of the present invention will be described below.

[0109] like Figure 6a , Figure 6bAs shown, the second phase shifter 20 according to Embodiment 2 of the present invention includes: a substrate 100, a connector 101, a first straight waveguide 102, a second straight waveguide 104, a third straight waveguide 118, a first U-shaped waveguide 106, a second U-shaped waveguide 122, a first resistor 108, a second resistor 110, a third resistor 112, a fourth resistor 120, a cathode 114, and an anode 116. The connector 101, the first straight waveguide 102, the second straight waveguide 104, the third straight waveguide 118, the first U-shaped waveguide 106, the second U-shaped waveguide 122, the first resistor 108, the second resistor 110, the third resistor 112, and the fourth resistor 120 are formed on the substrate 10 made of silicon material. The first resistor 108, the second resistor 110, the third resistor 112, and the fourth resistor 120 are made of silicon material doped with n++ or p++, respectively, and are respectively aligned along the direction of light transmission, i.e., the x-direction. Figure 6b It extends in a straight line in the horizontal direction.

[0110] Figure 6b In the middle, the first direct waveguide 102 is made of silicon material, along the direction of light transmission, i.e., the x-direction ( Figure 6b It extends in a straight line in the horizontal direction and is located between the first resistor 108 and the second resistor 110.

[0111] The second straight waveguide 104 is made of silicon material, extends in a straight line along the x-direction, and is located between the third resistor 112 and the second resistor 110.

[0112] The third straight waveguide 118 is made of silicon material, extends in a straight line along the x-direction, and is located between the third resistor 112 and the fourth resistor 120.

[0113] The first resistor 108, the first straight waveguide 102, the second resistor 110, the second straight waveguide 104, the third resistor 112, the third straight waveguide 118, and the fourth resistor 120 are arranged sequentially along the y-axis.

[0114] In the y direction ( Figure 6b In the vertical direction (as shown in the diagram), there are distances D between the first resistor 108 and the first straight waveguide 102, between the first straight waveguide 102 and the second resistor 110, between the second resistor 110 and the second straight waveguide 104, between the second straight waveguide 104 and the third resistor 112, between the third resistor 112 and the third straight waveguide 118, and between the third straight waveguide 118 and the fourth resistor 120. Here, distance D is equal to 1 micrometer.

[0115] The first straight waveguide 102, the second straight waveguide 104, the third straight waveguide 118, the first resistor 108, the second resistor 110, the third resistor 112, and the fourth resistor 120 have the same length L. Here, the length L is equal to 67 μm.

[0116] like Figure 6a As shown, the first straight waveguide 102, the second straight waveguide 104, the third straight waveguide 118, the first U-shaped waveguide 106, the second U-shaped waveguide 122, the first resistor 108, the second resistor 110, the third resistor 112, and the fourth resistor 120 have the same height H.

[0117] Multiple connectors 101, made of silicon, extend in a planar shape parallel to the substrate 100 and are respectively connected between the bottom of the first resistor 108 and the bottom of the first straight waveguide 102, between the bottom of the first straight waveguide 102 and the bottom of the second resistor 110, between the bottom of the second resistor 110 and the bottom of the second straight waveguide 104, between the bottom of the second straight waveguide 104 and the bottom of the third resistor 112, between the bottom of the third resistor 112 and the bottom of the third straight waveguide 118, and between the bottom of the third straight waveguide 118 and the bottom of the fourth resistor 120. The multiple connectors 101 have the same height h, and the height h of the multiple connectors 101 is less than the height H of the first straight waveguide 102, the second straight waveguide 104, the third straight waveguide 118, the first U-shaped waveguide 106, the second U-shaped waveguide 122, the first resistor 108, the second resistor 110, the third resistor 112, and the fourth resistor 120.

[0118] Figure 6b In the first resistor 108, one end of the top in the x direction is connected to the cathode 114, and the other end of the top in the x direction is connected to the anode 116.

[0119] The top of the second resistor 110 is connected to the cathode 114 in the x direction, and the other end of the top of the second resistor 110 in the x direction is connected to the anode 116.

[0120] The top of the third resistor 112 is connected to the cathode 114 in the x direction, and the other end of the top of the third resistor 112 in the x direction is connected to the anode 116.

[0121] The top of the fourth resistor 120 is connected to the cathode 114 in the x direction, and the other end of the top of the fourth resistor 120 in the x direction is connected to the anode 116.

[0122] One end of the first U-shaped waveguide 106 is connected to the end of the first straight waveguide 102 near the anode 116 in the x direction, and the other end of the first U-shaped waveguide 106 is connected to the end of the second straight waveguide 104 near the anode 116 in the x direction.

[0123] One end of the second U-shaped waveguide 122 is connected to the end of the second straight waveguide 104 near the cathode 114 in the x direction, and the other end of the second U-shaped waveguide 122 is connected to the end of the third straight waveguide 118 near the cathode 114 in the x direction.

[0124] Example 2 has a structure with three straight waveguides, two U-shaped waveguides, and four heating electrodes, as shown below. Figure 6a , Figure 6b As shown, compared to the conventional structure with one straight waveguide and two heating electrodes, in this embodiment 2, the total length of the multiple straight waveguides is equal to the length of the original single straight waveguide, and the total length of the multiple heating electrodes is equal to the total length of the original heating electrodes. Furthermore, the silicon resistors serving as heating electrodes and the optical waveguides are interleaved, with the middle silicon resistor sandwiched between two waveguides, to accumulate the phase change of the light transmitted in the waveguides. Therefore, the path length of light traveling through one straight waveguide in a conventional phase shifter is equal to the path length of light traveling through multiple straight waveguides in the phase shifter of this embodiment 2.

[0125] When the resistor generates heat that affects the refractive index of the optical waveguide, the magnitude of the cumulative phase of light propagating in the optical waveguide with the changed refractive index also changes. This makes the phase change of light in a conventional phase shifter in one straight waveguide equal to the cumulative phase change of light in multiple straight waveguides in the phase shifter of this embodiment 2. Therefore, the optical path of a conventional phase shifter with two heating electrodes and one straight waveguide can be replaced with the optical path of this invention with a series structure of four or more heating electrodes, three or more straight waveguides, and two or more U-shaped waveguides.

[0126] Compared with the phase shifter in Example 1, the phase shifter in Example 2 can further improve the thermal tuning efficiency and further reduce the total power consumption when changing the phase of light by thermal modulation.

[0127] In Embodiment 2 of the present invention, the number of heating electrodes is increased and the optical waveguide routing is optimized, i.e., there are 4 heating electrodes, 3 straight waveguides, and 2 U-shaped waveguides. By increasing the number of heating electrodes and waveguides and arranging them in an interlaced manner, and by rationally designing the number and length of the heating electrodes and waveguides, as well as their relative positions, the heat energy of the heating electrode located between the two optical waveguides can be utilized by the two adjacent optical waveguides. As a result, the average heat energy utilization rate of the heating electrode = (heat energy utilization rate of the left heating electrode + heat energy utilization rate of the middle heating electrode + heat energy utilization rate of the right heating electrode) / 4 = (50% + 100% + 100% + 50%) / 4 = 75%. Compared with the conventional thermally modulated phase shifter, the heat energy utilization rate of the thermally modulated phase shifter is increased by 25% (75% - 50% = 25%), which significantly improves the average heat energy utilization rate and thus significantly improves the thermal modulation efficiency of the thermally modulated phase shifter. The thermal modulation efficiency of Embodiment 2 is less than 10mW / π.

[0128] Example 3

[0129] Figure 7a This is a side view showing a thermally modulated phase shifter with multiple heating electrodes according to Embodiment 3 of the present invention. Figure 7b This is a top view showing a thermally adjustable phase shifter with multiple heating electrodes according to Embodiment 3 of the present invention. Refer to the following... Figure 7a , Figure 7b The detailed structure of the phase shifter in Embodiment 3 of the present invention will be described below.

[0130] like Figure 7a , Figure 7b As shown, the third phase shifter 30 according to Embodiment 3 of the present invention includes: a substrate 100, a connector 101, a first straight waveguide 102, a second straight waveguide 104, a first U-shaped waveguide 106, a first resistor 108, a second resistor 110, a third resistor 112, a cathode 114, an anode 116, a fifth heating electrode 130, and a sixth heating electrode 132. The connector 101, the first straight waveguide 102, the second straight waveguide 104, the first U-shaped waveguide 106, the first resistor 108, the second resistor 110, and the third resistor 112 are formed on the substrate 10 made of silicon material. The first resistor 108, the second resistor 110, and the third resistor 112 are respectively made of silicon material doped with n++ or p++, and are respectively positioned along the direction of light transmission, i.e., the x-direction (…). Figure 7b It extends in a straight line in the horizontal direction.

[0131] Figure 7b In the middle, the first direct waveguide 102 is made of silicon material, along the direction of light transmission, i.e., the x-direction ( Figure 7b It extends in a straight line in the horizontal direction and is located between the first resistor 108 and the second resistor 110.

[0132] The second straight waveguide 104 is made of silicon material, extends in a straight line along the x-direction, and is located between the third resistor 112 and the second resistor 110.

[0133] A fifth heating electrode 130, formed of a metal layer such as TIN or tungsten, is formed on the top of the first direct waveguide 102. The fifth heating electrode 130 extends along the x-axis and has the same width and length as the first direct waveguide 102. One end of the top of the fifth heating electrode 130 in the x-direction is connected to the cathode 114, and the other end of the top of the fifth heating electrode 130 in the x-direction is connected to the anode 116.

[0134] A sixth heating electrode 132, formed of a metal layer such as TIN or tungsten, is formed on the top of the second straight waveguide 104. The sixth heating electrode 132 extends along the x-axis and has the same width and length as the second straight waveguide 104. One end of the top of the sixth heating electrode 132 in the x-direction is connected to the cathode 114, and the other end of the top of the sixth heating electrode 132 in the x-direction is connected to the anode 116.

[0135] The first resistor 108, the first straight waveguide 102, the second resistor 110, the second straight waveguide 104, and the third resistor 112 are arranged sequentially along the y-axis.

[0136] In the y direction ( Figure 7b In the vertical direction, there is a distance D between the first resistor 108 and the first straight waveguide 102, a distance D between the first straight waveguide 102 and the second resistor 110, a distance D between the second resistor 110 and the second straight waveguide 104, and a distance D between the second straight waveguide 104 and the third resistor 112. Here, the distance D is equal to 1 micrometer.

[0137] The first straight waveguide 102, the second straight waveguide 104, the first resistor 108, the second resistor 110, and the third resistor 112 have the same length L. Here, the length L is equal to 100 μm.

[0138] like Figure 7a As shown, the first straight waveguide 102, the second straight waveguide 104, the first U-shaped waveguide 106, the first resistor 108, the second resistor 110, and the third resistor 112 have the same height H.

[0139] Multiple connectors 101, made of silicon, extend in a planar shape parallel to the substrate 100 and are respectively connected between the bottom of the first resistor 108 and the bottom of the first straight waveguide 102, between the bottom of the first straight waveguide 102 and the bottom of the second resistor 110, between the bottom of the second resistor 110 and the bottom of the second straight waveguide 104, and between the bottom of the second straight waveguide 104 and the bottom of the third resistor 112. The multiple connectors 101 have the same height h, and the height h of the multiple connectors 101 is less than the height H of the first straight waveguide 102, the second straight waveguide 104, the first U-shaped waveguide 106, the first resistor 108, the second resistor 110, and the third resistor 112.

[0140] Figure 7b In the first resistor 108, one end of the top in the x direction is connected to the cathode 114, and the other end of the top in the x direction is connected to the anode 116.

[0141] The top of the second resistor 110 is connected to the cathode 114 in the x direction, and the other end of the top of the second resistor 110 in the x direction is connected to the anode 116.

[0142] The top of the third resistor 112 is connected to the cathode 114 in the x direction, and the other end of the top of the third resistor 112 in the x direction is connected to the anode 116.

[0143] Figure 7b In the first U-shaped waveguide 106, one end is connected to the end of the first straight waveguide 102 near the anode 116 in the x direction, and the other end of the first U-shaped waveguide 106 is connected to the end of the second straight waveguide 104 near the anode 116 in the x direction.

[0144] Example 3 has a structure with two straight waveguides, one U-shaped waveguide, and five heating electrodes, as shown below. Figure 7a , Figure 7b As shown, compared to the conventional structure with one straight waveguide and three heating electrodes (two heating electrodes located on both sides of the straight waveguide and one heating electrode located above the straight waveguide), in this embodiment 3, the total length of the multiple straight waveguides is made equal to the length of the original single straight waveguide, and the total length of the multiple heating electrodes is also made equal to the total length of the original heating electrodes. Furthermore, the silicon resistors serving as heating electrodes and the optical waveguides are interleaved, with the middle silicon resistor sandwiched between two waveguides, to accumulate the phase change of the light transmitted in the waveguides. Therefore, the path length of light traveling through one straight waveguide in a conventional phase shifter is equal to the path length of light traveling through multiple straight waveguides in the phase shifter of this embodiment 3.

[0145] When the resistor generates heat that affects the refractive index of the optical waveguide, the magnitude of the cumulative phase of the light propagating in the optical waveguide with the changed refractive index also changes. This makes the phase change of light in a conventional phase shifter in one straight waveguide equal to the cumulative phase change of light in multiple straight waveguides in the phase shifter of this embodiment 3. Therefore, the optical path of a conventional phase shifter with a structure of three heating electrodes (two heating electrodes located on both sides of the straight waveguide and one heating electrode located above the straight waveguide) and one straight waveguide can be replaced with the optical path of this invention having a series structure of five or more heating electrodes (three heating electrodes located on both sides of the straight waveguide and two heating electrodes located above the straight waveguide), two or more straight waveguides, and one or more U-shaped waveguides.

[0146] Compared with conventional phase shifters with titanium nitride heating electrodes, the phase shifter in this embodiment 3 can significantly improve thermal tuning efficiency and greatly reduce total power consumption when changing the phase of light by thermal modulation.

[0147] In Embodiment 3 of the present invention, the number of heating electrodes is increased and the optical waveguide routing is optimized, resulting in five heating electrodes (three heating electrodes located on both sides of the straight waveguide and two heating electrodes located above the straight waveguide), two straight waveguides, and one U-shaped waveguide. By increasing the number of heating electrodes and waveguides and arranging them in an interlaced manner, and by rationally designing the number and length of the heating electrodes and waveguides, as well as their relative positions, the thermal energy of the heating electrode located between the two optical waveguides can be utilized by the two adjacent optical waveguides, thereby enabling… The average thermal energy utilization rate of the heating electrode = (thermal energy utilization rate of the left heating electrode + thermal energy utilization rate of the middle heating electrode + thermal energy utilization rate of the right heating electrode) / 3 = (50% + 100% + 50%) / 3 = 66.7%. Compared with the previous thermal phase shifter, the thermal energy utilization rate of the thermal phase shifter is increased by 16.7% (66.7% - 50% = 16.7%), which significantly improves the average thermal energy utilization rate, thereby significantly improving the thermal adjustment efficiency of the thermal phase shifter, making the thermal adjustment efficiency of Example 3 less than 10mW / π.

[0148] In summary, this invention presents a simple silicon photonic thermally modulated phase shifter, with the thermal tuning unit being a highly doped silicon resistor. By designing the number of resistors, the number of waveguides, and the relative positions of the resistors and silicon waveguides, the thermal tuning efficiency of the phase shifter can be reduced to less than 10 mW / π. This invention uses doped silicon as the heat source for the silicon photonic thermally modulated phase shifter. By designing the number and position of the doped silicon resistors and coordinating with a suitable optical waveguide route, the utilization rate of the heat energy absorbed by the optical waveguide in the thermal field can be improved, thereby increasing the thermal tuning efficiency. This invention employs mature and widely used silicon photonics processing technology without adding extra steps or material costs.

[0149] By designing the number of heating electrodes and their relative positions to the optical waveguide, and by rationally designing the optical waveguide route (U-shaped waveguide), the utilization rate of thermal energy absorbed by the optical waveguide and the thermal tuning efficiency of the phase shifter can be improved.

[0150] The above embodiments 1 and 3 are illustrated using a structure with three heating electrodes disposed on both sides of the waveguide as an example, and embodiment 2 is illustrated using a structure with four heating electrodes disposed on both sides of the waveguide as an example. The present invention can also be implemented using four or more heating electrodes disposed in the horizontal direction. For example, when the number of heating electrodes on both sides of the waveguide is 5, the thermal energy utilization rate is (50% + 100% + 100% + 100% + 50%) / 5 = 80%. When the number of heating electrodes on both sides of the waveguide is 10, the thermal energy utilization rate is (50% + 100% + 100% + 100% + 100% + 100% + 100% + 50%) / 10 = 90%. When the number of heating electrodes on both sides of the waveguide is 100, the thermal energy utilization rate is (50% + 100% × 98 + 50%) / 100 = 99%.

[0151] In embodiments 1 to 3 above, the distance D is 1 micrometer. As long as it does not affect the optical transmission, the distance D between the first resistor 108 and the first straight waveguide 102, the distance D between the first straight waveguide 102 and the second resistor 110, the distance D between the second resistor 110 and the second straight waveguide 104, the distance D between the second straight waveguide 104 and the third resistor 112, the distance D between the third resistor 112 and the third straight waveguide 118, and the distance D between the third straight waveguide 118 and the fourth resistor 120 can be any value greater than 0.

[0152] In the above embodiments 1 to 3, a SiO2 layer can be formed between the substrate and the waveguide.

[0153] The resistor and heating electrode of the present invention can also be arc-shaped. By setting an arc-shaped heating electrode between two arc-shaped waveguides, the utilization rate of thermal energy absorbed by the optical waveguide and the thermal tuning efficiency of the phase shifter can be improved.

[0154] This concludes the description of a silicon photoelectric thermally modulated phase shifter according to embodiments of the present disclosure. The market demands increasingly higher power consumption from silicon photoelectric thermally modulated phase shifters. This disclosure provides a silicon photoelectric thermally modulated phase shifter with a simple structure that improves thermal efficiency and significantly enhances thermal tuning efficiency, thereby further reducing the power consumption of the silicon photoelectric thermally modulated phase shifter.

[0155] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of the various embodiments of this disclosure without departing from the scope of this disclosure. While the dimensions and types of materials described herein are used to define parameters of the various embodiments of this disclosure, the embodiments are not intended to be restrictive but are exemplary. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of this disclosure should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. A phase shifter, characterized in that, include: The first waveguide is used to transmit optical signals; A second waveguide, which is arranged parallel to the first waveguide, is used to transmit optical signals; A first U-shaped waveguide, one end of which is connected to one end of the first waveguide and the other end of which is connected to one end of the second waveguide, is used to transmit optical signals; A first heating electrode is disposed parallel to the first waveguide; A second heating electrode is disposed parallel to the first waveguide; A third heating electrode, which is disposed parallel to the first waveguide; and Substrate, The first waveguide, the second waveguide, the first U-shaped waveguide, the first heating electrode, the second heating electrode, and the third heating electrode are formed on the substrate. The first waveguide is located between the first heating electrode and the second heating electrode. The second waveguide is located between the second heating electrode and the third heating electrode.

2. The phase shifter as described in claim 1, characterized in that, The top of the first waveguide is separated from the top of the first heating electrode and the top of the second heating electrode by a predetermined distance. The top of the second waveguide is separated from the top of the second heating electrode and the top of the third heating electrode by a specified distance.

3. The phase shifter as described in claim 1, characterized in that, The first waveguide, the second waveguide, and the first U-shaped waveguide are made of silicon material. The first heating electrode, the second heating electrode, and the third heating electrode are resistors made of silicon material doped with n++ or p++.

4. The phase shifter as described in claim 1, characterized in that, One end of the top of the first heating electrode is connected to the cathode, and the other end of the top of the first heating electrode is connected to the anode. One end of the top of the second heating electrode is connected to the cathode, and the other end of the top of the second heating electrode is connected to the anode. One end of the top of the third heating electrode is connected to the cathode, and the other end of the top of the third heating electrode is connected to the anode.

5. The phase shifter as described in claim 1, characterized in that, Also includes: A third waveguide, which is disposed parallel to the first waveguide on the substrate, is used to transmit optical signals; A second U-shaped waveguide, disposed on the substrate, has one end connected to the other end of the second waveguide and the other end connected to one end of the third waveguide. This second U-shaped waveguide is used to transmit optical signals. A fourth heating electrode is disposed on the substrate parallel to the first waveguide. The third waveguide is located between the third heating electrode and the fourth heating electrode.

6. The phase shifter as described in claim 5, characterized in that, Also includes: The top of the third waveguide is separated from the top of the third heating electrode and the top of the fourth heating electrode by a specified distance.

7. The phase shifter as described in claim 5, characterized in that, The third waveguide and the second U-shaped waveguide are made of silicon. The fourth heating electrode is a resistor made of silicon material doped with n++ or p++.

8. The phase shifter as described in claim 5, characterized in that, One end of the top of the fourth heating electrode is connected to the cathode, and the other end of the top of the fourth heating electrode is connected to the anode.

9. The phase shifter as claimed in claim 1, characterized in that, It also includes: a fifth heating electrode, which is disposed parallel to the first waveguide and on the first waveguide; and A sixth heating electrode is disposed parallel to the first waveguide and is disposed on the second waveguide.

10. The phase shifter as claimed in claim 9, characterized in that, One end of the top of the fifth heating electrode is connected to the cathode, and the other end of the top of the fifth heating electrode is connected to the anode. One end of the top of the sixth heating electrode is connected to the cathode, and the other end of the top of the sixth heating electrode is connected to the anode.

11. The phase shifter as claimed in claim 9, characterized in that, The fifth and sixth heating electrodes are made of TiN or tungsten.

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