Optical power modulator with unloaded transmission line

Abstract

The present invention relates to an optical power modulator having unloaded transmission lines, and discloses a structure for an optical power modulator and a method of manufacturing the structure for an optical power modulator. A first waveguide core includes first and second sections. A second waveguide core includes a first section that is laterally adjacent to the first section of the first waveguide core and a second section that is laterally adjacent to the second section of the first waveguide core. An interconnect structure is formed over the first waveguide core and the second waveguide core. The interconnect structure includes first and second transmission lines. The first transmission line is physically connected within the interconnect structure to the first section of the first waveguide core. The second transmission line includes a first section that is physically connected within the interconnect structure to the second section of the first waveguide core and a second section that is adjacent to the first transmission line.

Description

Technical Field

[0001] The present invention relates to photonics chips, and more particularly, to a structure for an optical power modulator and a method of fabricating a structure for an optical power modulator. Background Art

[0002] Photonics chips are used in many applications and systems, including but not limited to data communication systems and data computing systems. Photonics chips integrate optical components such as waveguides, optical switches, optical power splitters, and directional couplers, as well as electronic components such as field effect transistors, into a unified platform. Among other factors, integrating the two types of components on the same chip can reduce layout area, cost, and operating overhead.

[0003] An electro-optic modulator can act as an optical switch to modulate the amplitude or phase of an optical signal under the control of an electrical signal. This modulation can be used to convert a continuous optical signal into an encoded data stream containing binary data. One type of optical switch is a Mach-Zehnder interferometer (MZI) modulator implemented in silicon photonics technology. A drawback of this type of optical switch is that silicon exhibits weak electro-optic or free-carrier dispersion effects. For this reason, MZI modulators are characterized by large form factors with elongated silicon-based phase shifters arranged in a two-arm configuration. The bandwidth limitations of the long transmission lines associated with such elongated silicon-based phase shifters can have an adverse impact on the performance of MZI modulators.

[0004] There is a need for an improved structure for an optical power modulator and a method of fabricating a structure for an optical power modulator. Summary of the Invention

[0005] In an embodiment of the present invention, a structure for an optical power modulator is provided. The structure includes a first waveguide core having a first section and a second section. The structure further includes a second waveguide core having a first section that is laterally adjacent to the first section of the first waveguide core and a second section that is laterally adjacent to the second section of the first waveguide core. The structure also includes an interconnect structure located above the first waveguide core and the second waveguide core. The interconnect structure includes a first transmission line and a second transmission line. The first transmission line is physically connected to the first section of the first waveguide core within the interconnect structure. The second transmission line includes a first section that is physically connected to the second section of the first waveguide core within the interconnect structure and a second section that is adjacent to the first transmission line.

[0006] In an embodiment of the present invention, a method of forming a structure for an optical power modulator is provided. The method includes forming a first waveguide core having a first section and a second section, forming a second waveguide core including a first section that is laterally adjacent to the first section of the first waveguide core and a second section that is laterally adjacent to the second section of the first waveguide core, and forming an interconnect structure above the first waveguide core and the second waveguide core. The interconnect structure includes: a first transmission line that is physically connected to the first section of the first waveguide core within the interconnect structure, and a second transmission line including a first section that is physically connected to the second section of the first waveguide core within the interconnect structure and a second section that is adjacent to the first transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The drawings included in and constituting a part of this specification illustrate various embodiments of the present invention and, together with the general description of the present invention known above and the detailed description of the embodiments known below, are used to explain the embodiments of the present invention. In the various drawings, the same reference numerals represent the same features.

[0008] Figure 1 is a top view of a structure in an initial manufacturing stage of a processing method according to an embodiment of the present invention.

[0009] Figure 2 is generally along Figure 1 a cross-sectional view of the structure taken along line 2-2 in

[0010] Figure 2A is generally along Figure 1 a cross-sectional view of the structure taken along line 2A-2A in

[0011] Figure 3 is atFigure 1 Top view of the structure in a subsequent manufacturing stage.

[0012] Figure 4 is a cross-sectional view of the structure taken generally along line 4-4 in Figure 3 .

[0013] Figure 4A is a cross-sectional view of the structure taken generally along line 4A-4A in Figure 3 .

[0014] Figure 5 Top view of the structure according to an alternative embodiment of the present invention.

[0015] Figure 6 is in Figure 5 Top view of the structure in a subsequent manufacturing stage.

[0016] Figure 7 Top view of the structure according to an alternative embodiment of the present invention.

[0017] Figure 8 is in Figure 7 Top view of the structure in a subsequent manufacturing stage. DETAILED DESCRIPTION

[0018] Referring to Figure 1 , Figure 2 , Figure 2A and according to an embodiment of the present invention, a structure 10 for an optical power modulator includes waveguide cores 12, 14, an optical splitter 16 that couples a routing waveguide core 20 to the waveguide cores 12, 14 at an input port, and an optical combiner 18 that couples a routing waveguide core 22 to the waveguide cores 12, 14 at an output port. The optical splitter 16 and the optical combiner 18 may include a multimode interference region that is configured to provide a desired coupling ratio, such as a 50%-50% coupling ratio, at the output port. The waveguide cores 12, 14 are laterally spaced apart to provide a gap that separates the waveguide core 12 from the waveguide core 14. The waveguide core 12 is aligned along a longitudinal axis 13, and the waveguide core 14 is aligned along a longitudinal axis 15, which may be oriented parallel or substantially parallel to the longitudinal axis 13.

[0019] The waveguide cores 12, 14 can define a phase shifter of the structure 10. In this regard, the waveguide core 12 can include a doped region 28 and a doped region 30 of opposite conductive types adjacent along a p-n junction, and the waveguide core 14 can also include a doped region 29 and a doped region 31 of opposite conductive types adjacent along a p-n junction. The doped regions 28, 29 can be formed simultaneously in the waveguide cores 12, 14 by a masked ion implantation process, and the doped regions 30, 31 can be formed simultaneously in the waveguide cores 12, 14 by a separate masked ion implantation process. In one embodiment, the semiconductor material of the doped regions 28, 29 can be doped with a p-type dopant (e.g., boron) providing p-type conductivity, and the semiconductor material of the doped regions 30, 31 can be doped with an n-type dopant (e.g., arsenic) providing n-type conductivity. A heavily doped region (not shown) for reducing resistance can be formed in portions of the doped regions 28, 29 and portions of the doped regions 30, 31, and is used to establish an electrical contact for biasing the p-n junction.

[0020] The waveguide cores 12, 14 can be divided into segments or sections characterized by individual lengths L1 and L2, and the sum of the individual lengths L1 and L2 is equal to the total length above the modulated portion of the phase shifter. The section of the waveguide core 12 having length L1 is positioned laterally adjacent to the section of the waveguide core 14 having length L1, and the section of the waveguide core 12 having length L2 is positioned laterally adjacent to the section of the waveguide core 14 having length L2. In one embodiment, the length L1 can be equal to the length L2. In one embodiment, the length L1 can be substantially equal to the length L2. In one embodiment, the length L1 and the length L2 can each be substantially equal to 1 millimeter. The sections of the waveguide core 12 can be connected by an intervening waveguide section 17 defining a transition between different sections, and the sections of the waveguide core 14 can be connected by an intervening waveguide section 19 defining a transition between different sections. Different sections of the waveguide core 12 each include the doped regions 28, 30, and different sections of the waveguide core 14 each include the doped regions 29, 31.

[0021] The section of waveguide core 12 having length L1 is positioned closer to the optical splitter 16 than the section of waveguide core 12 having length L2. Thus, the split light is directed to propagate through the section of waveguide core 12 having length L1 before propagating through the section of waveguide core 12 having length L2. The section of waveguide core 14 having length L1 is positioned closer to the optical splitter 16 than the section of waveguide core 14 having length L2. Thus, the split light is directed to propagate through the section of waveguide core 14 having length L1 before propagating through the section of waveguide core 14 having length L2.

[0022] The waveguide cores 12, 14, the optical splitter 16, the optical combiner 18, and the routing waveguide cores 20, 22 may be composed of single-crystalline semiconductor material, such as single-crystalline silicon. In one embodiment, the single-crystalline semiconductor material may be sourced from the device layer of a silicon-on-insulator (SOI) substrate, which further includes a dielectric layer 24 provided by a buried oxide layer and a substrate 26 composed of single-crystalline semiconductor material (such as single-crystalline silicon). The waveguide cores 12, 14, the optical splitter 16, the optical combiner 18, and the routing waveguide cores 20, 22 may be patterned from the device layer by lithography and etching processes during front-end-of-line processing, and the waveguide cores 12, 14, the optical splitter 16, the optical combiner 18, and the routing waveguide cores 20, 22 may be in direct contact with the dielectric layer 24.

[0023] Referring to Figure 3 , Figure 4 , Figure 4A where like reference numerals denote Figure 1 , Figure 2features that are the same, and in subsequent manufacturing stages, an interconnect structure 32 can be formed through middle-of-line and back-end-of-line processing over the waveguide cores 12, 14, splitter 16, optical combiner 18, routing waveguide cores 20, 22, and dielectric layer 24. The interconnect structure 32 can include multiple wiring levels that can be formed through features of deposition, polishing, lithography, and etching techniques of the damascene process. Specifically, for each wiring level, an interlayer dielectric layer can be deposited and patterned using lithography and etching processes to define trenches and via openings, the trenches and via openings are lined with a barrier layer (e.g., a bilayer of tantalum and tantalum nitride), and are filled with a planarized conductor (e.g., copper) to define lines and vias, and the lines and vias connect the lines in different wiring levels. Each interlayer dielectric layer of the interconnect structure 32 can be composed of an inorganic dielectric material (e.g., silicon dioxide or a low-k dielectric material), which is deposited through, for example, chemical vapor deposition.

[0024] Transmission lines 34, 36, 38, 40 and transmission lines 42, 44, 46, 48, 50 are included in the interconnect structure 32. In one embodiment, the transmission lines 34, 36, 38, 40, 42, 44, 46, 48, 50 can be located in the topmost wiring level of the interconnect structure 32. The vias and lines in the multiple wiring levels (simplified for illustration) provide individual interconnections 56, 58, 60, 62 between the doped regions 28, 30 of the waveguide cores 12, 14 and the transmission lines 34, 36, 38, 40, 42, 44, 46, 48, 50. Although not shown, the multiple middle wiring levels of the interconnect structure 32 can be laterally offset relative to the waveguide cores 12, 14 from the transmission lines 34, 36, 38, 40, 42, 44, 46, 48, 50. One or more heaters (not shown) can be provided for adjusting the performance of the structure 10, each of the transmission lines 42, 44, 46, 48, 50 can be coupled to a ground potential, the transmission lines 34, 36 can be coupled to a signal source, and the transmission lines 38, 40 can be coupled to different signal sources.

[0025] Transmission lines 34, 36 provide signal electrodes that are coupled in parallel with driver 52, which is shared by transmission lines 34, 36. Driver 52 includes components such as a driver amplifier that is configured to supply data in the form of a radio frequency signal to transmission lines 34, 36 for modulating the effective refractive index of waveguide core 12. Accordingly, transmission line 34 and transmission line 36 simultaneously receive the same signal from driver 52.

[0026] Transmission line 36 is physically coupled to a section of waveguide core 12 having length L1 through an intermediate portion of interconnect structure 32, and transmission line 34 is physically coupled to a section of waveguide core 12 having length L2 through an intermediate portion of interconnect structure 32. Transmission line 34 is not connected to the section of waveguide core 12 having length L1 through an interconnect entity within interconnect structure 32, and transmission line 34 is not connected to the section of waveguide core 12 having length L2 through an interconnect entity within interconnect structure 32. A grounded transmission line 46 is coupled to the doped region 30 of waveguide core 12 over lengths L1 and L2 through interconnect structure 32, and the doped region 30 of waveguide core 12 may define the cathode of structure 10.

[0027] Transmission lines 38, 40 provide signal electrodes that are coupled in parallel with driver 54, which is shared by transmission lines 38, 40 and may be different from driver 52. Driver 54 includes components such as a drive amplifier that is configured to supply data in the form of a radio frequency signal to transmission lines 38, 40 for modulating the effective refractive index of waveguide core 14. Accordingly, transmission line 38 and transmission line 40 simultaneously receive the same signal from driver 54.

[0028] Transmission line 38 is physically coupled to a section of waveguide core 14 having length L1 through an intermediate portion of interconnect structure 32, and transmission line 40 is physically coupled to a section of waveguide core 14 having length L2 through an intermediate portion of interconnect structure 32. Transmission line 40 is not coupled to the section of waveguide core 14 having length L1 through interconnect structure 32, and transmission line 38 is not coupled to the section of waveguide core 14 having length L2 through interconnect structure 32. A grounded transmission line 46 is coupled to the doped region 30 of waveguide core 14 over lengths L1 and L2 through interconnect structure 32, and the doped region 30 of waveguide core 14 may define the cathode of structure 10.

[0029] Drivers 52, 54 provide individual signals with a phase difference to the doped regions 28 of waveguide core 12 and the doped region 29 of waveguide core 14 in a coordinated manner through the interconnect structure 32, which can define the anode of the phase shifter of structure 10. For example, the phase difference can be about 180 degrees. Thus, the phase modulation of the optical signals guided by the different waveguide cores 12, 14 can have the same absolute value but different signs (e.g., opposite signs). In an alternative embodiment, individual signals with the necessary phase shift can be provided to the doped region 28 of waveguide core 12 and the doped region 29 of waveguide core 14 by a single driver.

[0030] Transmission lines 36, 38 are located in structure 10 for a length comparable to length L1 and are physically coupled within the interconnect structure 32 to the doped regions 28, 29 in waveguide cores 12, 14 at length L1 to provide loading. Transmission line 36 can extend longitudinally parallel to a section of transmission line 46 and terminate at end face 35, and transmission line 38 can extend longitudinally parallel to a section of transmission line 46 and terminate at end face 37. In this regard, transmission line 36 is truncated to a length equal to or substantially equal to length L1, and transmission line 38 is truncated to a length equal to or substantially equal to length L1. The grounded section of transmission line 46 is laterally positioned between transmission line 36 and transmission line 38 at length L1.

[0031] At length L1, a section of transmission line 34 is located within the interconnect structure 32 adjacent to transmission line 36, and transmission line 44 is laterally positioned within the interconnect structure 32 between the section of transmission line 34 and transmission line 36. At length L1, a section of transmission line 40 is located within the interconnect structure 32 adjacent to transmission line 38, and transmission line 48 is laterally positioned within the interconnect structure 32 between transmission line 38 and the section of transmission line 40. Thus, transmission lines 36 and 38 are each laterally arranged between the grounded transmission lines at length L1.

[0032] Since transmission line 34 is not physically connected to the doped region 28 of waveguide core 12 within the interconnect structure 32 at length L1, transmission line 34 is not loaded at length L1. Transmission line 34 has a bend 33 that provides a direction change such that transmission line 34 laterally approaches transmission line 46 at the transition provided by waveguide section 17 ( Figure 1 ) and then turns to align parallel to transmission line 46 at length L2. After the direction change, transmission line 34 can extend longitudinally parallel or substantially parallel to transmission lines 42, 46 and terminate at end face 35. The truncation of transmission line 36 and the truncation of the grounded transmission line 44 release space in the layout of structure 10 for the direction change. Transmission line 42 includes a bend that provides a similar direction change such that transmission line 34 is laterally arranged between the grounded transmission lines at both lengths L1 and L2.

[0033] Because the transmission line 40 is not physically connected to the doped region 29 of the waveguide core 14 within the interconnect structure 32 over a length L1, the transmission line 40 is unloaded over the length L1. The transmission line 40 has a bend 39 that provides a direction change such that the transmission line 40 laterally approaches the transmission line 46 at the transition provided by the waveguide section 19( Figure 1 ) and then turns to align parallel to the transmission line 46 over a length L2. After the direction change, the transmission line 40 can extend longitudinally parallel or substantially parallel to the transmission lines 46, 50 and terminate at the end face 41. The truncation of the transmission line 38 and the truncation of the grounded transmission line 48 release space in the layout of the structure 10 for the direction change. The transmission line 50 includes a bend that provides a similar direction change such that the transmission line 40 is laterally arranged between the grounded transmission lines over both lengths L1 and L2.

[0034] After the direction change, the transmission line 34 has a section located in the structure 10 over a length comparable to the length L2. The section of the transmission line 34 is coupled to the doped region 28 of the waveguide core 12 over the length L2 to provide a load, and the length of the loaded section of the transmission line 34 is equal to or substantially equal to the length L2. The transmission line 40 has a section located in the structure 10 over a length comparable to the length L2. The section of the transmission line 40 is coupled to the doped region 29 of the waveguide core 14 over the length L2 to provide a load, and the length of the loaded section of the transmission line 40 is equal to or substantially equal to the length L2. A section of the grounded transmission line 46 is laterally positioned between the loaded section of the transmission line 34 and the loaded section of the transmission line 40 over the length L2.

[0035] In use, the structure 10 provides an optical interferometer where the incident light reaching the routing waveguide core 20 is split by the beam splitter 16, experiences a phase shift while propagating along separate paths defined by the waveguide cores 12, 14, and is then recombined by the optical combiner 18. If the phase shift between the two paths is equal to 0°, there is maximum constructive interference, and the optical power output at the routing waveguide core 22 is maximized (i.e., ideal logic 1). If the phase shift between the two paths is equal to 180°, there is maximum destructive interference, and the optical power output at the routing waveguide core 22 is minimized (i.e., ideal logic 0). The structure 10 changes the relative phase between the two paths through a modulation voltage of the electro-optic effect, generating a modulated output signal at the output. The amount of phase shift generated by the structure 10 is proportional to the radio frequency voltages applied from the transmission lines 34, 36, 38, 40 and the lengths of the phase shifters.

[0036] The transmission lines 36, 38 of structure 10 are fully loaded over a portion of the length of the phase shifter (i.e., length L1) through their connection to the phase shifter within the interconnect structure 32, and the transmission lines 34, 40 of structure 10 are fully loaded over another portion of the length of the phase shifter (i.e., length L2) through their connection to the phase shifter within the interconnect structure 32. The transmission lines 34, 40 of structure 10 are unloaded (i.e., not loaded) over length L1, which results in low loss over this portion of the length of the phase shifter. The structure 10, which can be characterized as a traveling wave Mach-Zehnder modulator, can exhibit an extended electro-optic bandwidth due to shortening the loaded portions of the transmission lines 34, 36, 38, 40 by segmentation while maintaining a minimum insertion loss (IL) and a maximum extinction ratio (ER). The electro-optic bandwidth of the segmented structure 10 can be extended without affecting the effective length of structure 10. Since the transmission lines 34, 36 are typically driven by driver 52 and the transmission lines 38, 40 are typically driven by driver 54, no electronic timing circuit is required to control the timing of the applied electrical signals to match the optical delays between different sections of the waveguide cores 12, 14.

[0037] Referring Figure 5 , Figure 6 And according to an alternative embodiment, the sections of waveguide core 12 can be laterally offset from each other, and the sections of waveguide core 14 can be laterally offset from each other. The sections of waveguide core 12 having length L2 are aligned along longitudinal axis 13a, which can be oriented parallel or substantially parallel to longitudinal axis 13, and the sections of waveguide core 14 having length L2 are aligned along longitudinal axis 15a, which can be oriented parallel or substantially parallel to longitudinal axis 15. The sections of waveguide core 12 having length L1 are aligned along longitudinal axis 13, which is laterally spaced from longitudinal axis 13a. The sections of waveguide core 12 having length L2 are aligned along longitudinal axis 15, which is laterally spaced from longitudinal axis 15a.

[0038] Due to the lateral offset of the sections of waveguide core 12 provided by waveguide section 17 ( Figure 1 ), the transmission lines 34 and 42 do not necessarily require a direction change. Due to the lateral offset of the sections of waveguide core 14 provided by waveguide section 19 ( Figure 1 ), the transmission lines 40 and 50 do not necessarily require a direction change. Due to the elimination of direction changes, the transmission lines 44, 48 can extend over the entire length of the waveguide cores 12, 14.

[0039] The grounded transmission line 46 is coupled to the doped region 30 of the waveguide core 12 over a length L1 and to the doped region 31 of the waveguide core 14 over a length L1 through the interconnect structure 32. The doped region 30 of the waveguide core 12 can be coupled to the transmission line 42 or the transmission line 44 over a length L2, and the doped region 31 of the waveguide core 14 can be coupled to the transmission line 48 or the transmission line 50 over a length L2.

[0040] Referring Figure 7 、 Figure 8 And according to an alternative embodiment, the waveguide cores 12, 14 can be divided into a plurality of sections that are laterally offset from each other, and each of the waveguide cores 12, 14 can also be divided into more than one pair of sections. For example, each of the waveguide cores 12, 14 can also be divided into sections characterized by adding a length L3 such that the approximate total length of the waveguide cores 12, 14 is equal to the sum of the lengths L1, L2, L3. In one embodiment, the length L3 can be equal to the length L1, and the length L3 can be equal to the length L2. In one embodiment, the length L3 can be substantially equal to the length L1, and the length L3 can be substantially equal to the length L2. In one embodiment, the lengths L1, L2, and L3 can each be equal to 0.6 millimeters.

[0041] Transmission lines 64, 66 similar to the transmission lines 34, 36, 38, 40 and transmission lines 68, 70 similar to the transmission lines 42, 44, 46, 48, 50 are included in the interconnect structure 32 to accommodate the additional sections of the waveguide cores 12, 14, and the transmission lines 68, 70 can be coupled to the ground potential.

[0042] The transmission line 64 provides a signal electrode that is coupled in parallel with the driver 52 and the transmission lines 34, 36. Therefore, the transmission lines 34, 36, 64 receive the same signal from the driver 52 at the same time, and the transmission line 64 is physically coupled to the doped region 28 in the section of the waveguide core 12 over a length L3 through the middle part of the interconnect structure 32. The transmission line 64 is not coupled to the doped region 28 in the section of the waveguide core 12 having a length L1, nor is it coupled to the doped region 28 in the section of the waveguide core 12 having a length L2.

[0043] The transmission line 66 provides a signal electrode that is coupled in parallel with the driver 54 and the transmission lines 38, 40. Therefore, the transmission lines 38, 40, 66 receive the same signal from the driver 54 at the same time. The transmission line 66 is physically coupled to the doped region 29 in the section of the waveguide core 14 over a length L3 through the middle part of the interconnect structure 32. The transmission line 66 is not coupled to the doped region 29 in the section of the waveguide core 14 having a length L1, nor is it coupled to the section of the waveguide core 14 having a length L2.

[0044] The transmission line 64 is coupled to the doped region 28 in the waveguide core 12 over a length L3 to provide a load, and the transmission line 66 is coupled to the doped region 29 in the waveguide core 14 over a length L3 to provide a load. The ground portions of the transmission lines 42 and 68 are laterally adjacent to the transmission line 64 over the entire length of the transmission line 64, and the ground portions of the transmission lines 50 and 70 are laterally adjacent to the transmission line 66 over the entire length of the transmission line 66.

[0045] Since there is no connection to the doped regions 28, 29 in the waveguide cores 12, 14, the transmission lines 64, 66 are unloaded over lengths L1 and L2. The length of the loaded portion of the transmission line 64 is equal to or substantially equal to the length L3 of the corresponding section of the waveguide core 12, and the length of the loaded portion of the transmission line 66 is equal to or substantially equal to the length L3 of the corresponding portion of the waveguide core 14.

[0046] The method as described above is used in the manufacture of integrated circuit chips, and the final integrated circuit chips can be distributed in the form of the original wafer (e.g., as a single wafer with multiple unpackaged chips), as bare die, or in a packaged form. The chips can be integrated with other chips, discrete circuit components, and / or other signal processing devices as part of an intermediate product or a final product. The final product can be any product containing an integrated circuit chip, such as a calculator product or a smart phone having a central processor.

[0047] Approximating language, such as "about", "approximately", and "substantially", as used herein, is not limited to a precise particular value. The approximating language may correspond to the precision of the instrument used for measuring a value, and unless relying on the precision of the instrument, may represent + / - 10% of the stated value.

[0048] Terms such as "vertical", "horizontal", etc., as used herein, are used as examples to establish a reference frame and are not limiting. The term "horizontal" as used herein is defined as a plane parallel to the conventional plane of the semiconductor substrate, regardless of its actual three-dimensional spatial orientation. The terms "vertical" and "orthogonal" refer to directions perpendicular to the horizontal plane as just defined. The term "lateral" refers to a direction within that horizontal plane.

[0049] A feature that is "connected" or "coupled" to another feature may be directly connected or coupled to that other feature, or there may be one or more intermediate features. If there are no intermediate features, the feature may be "directly connected" or "directly coupled" to the other feature. If there is at least one intermediate feature, the feature may be "indirectly connected" or "indirectly coupled" to the other feature. A feature that is "on" or "in contact with" another feature may be directly on or in direct contact with that other feature, or there may be one or more intermediate features. If there are no intermediate features, the feature may be directly "on" or "in direct contact with" the other feature. If there is at least one intermediate feature, the feature may be "indirectly" "on" or "in indirect contact with" the other feature. If one feature extends over another feature and covers a portion of the other feature, the different features may overlap.

[0050] The description of the various embodiments of the present invention is for illustrative purposes only and is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein have been chosen to best explain the principles of the embodiments, the practical application, or a technical improvement over technologies known in the marketplace, or to enable those of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A structure for an optical power modulator, characterized in that, The structure includes: A first waveguide core including a first section and a second section; A second waveguide core including a first section that is laterally adjacent to the first section of the first waveguide core and a second section that is laterally adjacent to the second section of the first waveguide core; An interconnect structure located above the first waveguide core and the second waveguide core. The interconnect structure includes a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line. The first transmission line is physically connected to the first section of the first waveguide core. The third transmission line is physically connected to the first section of the second waveguide core. The second transmission line includes a first section physically connected to the second section of the first waveguide core and a second section adjacent to the first transmission line. And the fourth transmission line includes a first section physically connected to the second section of the second waveguide core and a second section adjacent to the third transmission line; A first driver coupled in parallel to the first transmission line and the second transmission line; And A second driver coupled in parallel to the third transmission line and the fourth transmission line.

2. The structure according to claim 1, wherein, The first transmission line is not physically connected to the second section of the first waveguide core within the interconnect structure.

3. The structure according to claim 1, characterized in that, The second transmission line is not physically connected to the first section of the first waveguide core within the interconnect structure.

4. The structure according to claim 1, wherein The first transmission line has an end face near the transition from the first section to the second section of the second transmission line.

5. The structure according to claim 1, wherein The first section of the first waveguide core has a first length, and the second section of the first waveguide core has a second length equal to the first length.

6. The structure according to claim 1, characterized in that, It further includes: A first ground transmission line laterally positioned between the second section of the second transmission line and the first transmission line.

7. The structure according to claim 1, wherein The second section of the first waveguide core is laterally offset from the first section of the first waveguide core.

8. The structure according to claim 1, wherein The first section of the second transmission line is spaced apart from the second section of the first waveguide core by a first distance, and the second section of the second transmission line is spaced apart from the first section of the first waveguide core by a second distance greater than the first distance.

9. The structure according to claim 8, characterized in that, The second transmission line includes a bend between the first section and the second section of the second transmission line.

10. The structure according to claim 1, wherein, The first waveguide core has a first doped region and a second doped region adjacent to the first doped region along a p-n junction. The first transmission line is physically connected to the first doped region in the first section of the first waveguide core, and the second section of the second transmission line is physically connected to the first doped region in the second section of the first waveguide core.

11. The structure according to claim 10, characterized in that, The interconnect structure includes a first interconnect that physically connects the first transmission line to the first doped region in the first section of the first waveguide core, and the interconnect structure includes a second interconnect that physically connects the second transmission line to the first doped region in the second section of the first waveguide core.

12. A method of forming a structure for an optical power modulator, characterized in that, The method includes: Forming a first waveguide core including a first section and a second section; Forming a second waveguide core including a first section that is laterally adjacent to the first section of the first waveguide core and a second section that is laterally adjacent to the second section of the first waveguide core; Forming an interconnect structure above the first waveguide core and the second waveguide core, Wherein, the interconnect structure includes a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line. The first transmission line is physically connected to the first section of the first waveguide core. The third transmission line is physically connected to the first section of the second waveguide core. The second transmission line includes a first section physically connected to the second section of the first waveguide core and a second section adjacent to the first transmission line. And the fourth transmission line includes a first section physically connected to the second section of the second waveguide core and a second section adjacent to the third transmission line; Couple a first driver in parallel to the first transmission line and the second transmission line; and Couple a second driver in parallel to the third transmission line and the fourth transmission line.

13. The method according to claim 12, wherein The first transmission line is not physically connected to the second section of the first waveguide core within the interconnect structure.

14. The method according to claim 12, wherein The second transmission line is not physically connected to the first section of the first waveguide core within the interconnect structure.

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