Optical device

Abstract

The optical device according to the present invention comprises: a lower electrode; a lower cladding on the lower electrode; a first input waveguide, a second input waveguide, a first distribution unit, a first output waveguide, a second output waveguide, a second distribution unit, a first core, and a second core which are on the lower cladding; an upper cladding which covers the first and second cores; and an upper electrode on the upper cladding. The first input waveguide, the second input waveguide, the first core, and the second core are connected to the first distribution unit. The first output waveguide, the second output waveguide, the first core, and the second core are connected to the second distribution unit.

Description

optical device

[0001] The present invention relates to an optical device, and more specifically, to an optical device comprising a spiral-shaped push-pull Mach-Zehnder interferometer optical modulator.

[0002] Currently, in optical communication technology, long-distance and high-bit-rate communication primarily uses Mach-Zehnder interferometer (MZI)-based optoelectronic modulators.

[0003] MZI modulators perform optical modulation using interference phenomena caused by changes in the refractive index of the optical path due to the application of voltage. In addition to changing the intensity of light, MZI modulators can be used to increase bandwidth through coherent communication, which increases bandwidth by subdividing phase modulation. Various studies are continuing to miniaturize and highly integrate MZI modulators to improve their performance and usability.

[0004] The problem that the present invention aims to solve is to provide an optical device including a Mach-Zehnder interferometer with improved performance and usability.

[0005] An optical device according to some embodiments comprises: a lower electrode; a lower cladding on the lower electrode; a first input waveguide, a second input waveguide, a first distribution unit, a first output waveguide, a second output waveguide, a second distribution unit, a first core, and a second core on the lower cladding; an upper cladding covering the first and second cores; and an upper electrode on the upper cladding, wherein the first input waveguide, the second input waveguide, the first core, and the second core are connected to the first distribution unit, and the first output waveguide, the second output waveguide, the first core, and the second core are connected to the second distribution unit, and the lower electrode, the first core, and the upper electrode are vertically superimposed on each other, and the lower electrode, the second core, and the upper electrode are vertically superimposed on each other, and the polarization direction of the first core and the polarization direction of the second core may be opposite to each other.

[0006] An optical device according to some embodiments may comprise a substrate; a lower electrode on the substrate; a lower cladding on the lower electrode; a first core and a second core on the lower cladding; an upper cladding covering the first and second cores; and an upper electrode on the upper cladding, wherein the lower electrode, the first core and the upper electrode overlap perpendicularly with each other, the lower electrode, the second core and the upper electrode overlap perpendicularly with each other, and the first core and the second core may comprise a ferroelectric material that is polarized in opposite directions.

[0007] A method for manufacturing an optical device according to some embodiments may include forming a lower electrode on a substrate; forming a lower cladding on the lower electrode; forming a core layer comprising a ferroelectric material polarized in a first direction on the lower cladding; forming a poling electrode that overlaps with the core layer; and applying a voltage to the lower electrode and the poling electrode to change the polarization direction of a first portion of the core layer.

[0008] An optical device according to embodiments of the concept of the present invention may include a first core and a second core comprising materials polarized in different directions. Accordingly, the first core and the second core can perform optical phase modulation operations in different directions by an electric field applied from one upper electrode, and thus push-pull phase modulation can be achieved, thereby improving the efficiency of the modulator by twofold.

[0009] In an optical device according to embodiments of the concept of the present invention, the lower electrode and the upper electrode may overlap each other. Accordingly, the integration density of the optical device can be improved, and miniaturization can be facilitated.

[0010] An optical device according to embodiments of the concept of the present invention may have a first core, a second core, and an upper electrode that overlaps both the first core and the second core in a spiral shape. Accordingly, the integration density of the optical device can be improved, and miniaturization can be facilitated.

[0011] An optical device according to embodiments of the concept of the present invention may include curved portions having the shape of an Euler bend curve in the first core and the second core, thereby reducing the change in the polarization direction of light passing through the first core and the second core.

[0012] An optical device according to embodiments of the concept of the present invention may include a first core and a second core in a spiral shape including straight sections, thereby reducing the change in the polarization direction of light as it passes through the curved sections of the first core and the second core.

[0013] FIG. 1a is a drawing showing an optical device according to some embodiments.

[0014] Figure 1b is a cross-sectional view along line II' of Figure 1a.

[0015] FIG. 1c is a cross-sectional view along the line II-II' of FIG. 1a.

[0016] FIG. 1d is a cross-sectional view along the line III-III' of FIG. 1a.

[0017] FIGS. 2a and 2b are drawings illustrating the operation of an optical device according to some embodiments.

[0018] FIG. 3a is a graph showing the relative values ​​of the intensity of reflected light traveling in the core of an optical device according to some embodiments as a function of frequency.

[0019] FIG. 3b is a graph showing the relative values ​​of the intensity of incident light traveling in the core of an optical device according to some embodiments as a function of frequency.

[0020] FIG. 3c is a graph showing the impedance between the upper electrode and the lower electrode of an optical device according to some embodiments as a function of frequency.

[0021] FIG. 3d is a graph showing the group refractive index of the core of an optical device according to some embodiments as a function of frequency.

[0022] FIGS. 4a, 4b, 4c, 4d, 4e, 4f, and 4g are drawings illustrating a method for manufacturing an optical device according to some embodiments.

[0023] FIGS. 5a, 5b, 5c, 5d, 5e, and 5f are drawings illustrating a method for manufacturing an optical device according to some embodiments.

[0024] FIG. 6 is a drawing showing an optical device according to some embodiments.

[0025] FIG. 7 is a drawing showing an optical device according to some embodiments.

[0026] FIG. 8 is a drawing showing an optical device according to some embodiments.

[0027] FIG. 9 is a drawing showing an optical device according to some embodiments.

[0028] FIG. 1a is a drawing showing the best mode for carrying out the present invention.

[0029] Hereinafter, an optical device according to embodiments of the concept of the present invention will be described in detail with reference to the drawings.

[0030] FIG. 1a is a drawing showing an optical device according to some embodiments. FIG. 1b is a cross-sectional view along line II' of FIG. 1a. FIG. 1c is a cross-sectional view along line II-II' of FIG. 1a. FIG. 1d is a cross-sectional view along line III-III' of FIG. 1a.

[0031] Referring to FIGS. 1a and 1b, a substrate (100) may be provided. In some embodiments, the substrate (100) may be a semiconductor substrate. For example, the substrate (100) may comprise Si. The substrate (100) may have the form of a plate extending along a plane extending in a first direction (D1) and a second direction (D2). The first direction (D1) and the second direction (D2) may intersect each other. For example, the first direction (D1) and the second direction (D2) may be horizontal directions orthogonal to each other.

[0032] A lower electrode (LE) may be provided on a substrate (100). The lower electrode (LE) may cover the upper surface of the substrate (100). The lower electrode (LE) may include a conductive material. For example, the lower electrode (LE) may include Au. The thickness of the lower electrode (LE) in the third direction (D3) may be 0.3 μm or more and 1.1 μm or less.

[0033] A lower cladding (LC) may be provided on the lower electrode (LE). The lower cladding (LC) may cover the upper surface of the lower electrode (LE). The lower cladding (LC) may include an insulating material. For example, the lower cladding (LC) may include SiO2. The thickness of the lower cladding (LC) in the third direction (D3) may be 1 μm or more and 5 μm or less.

[0034] A core layer (200) may be disposed on a lower cladding (LC). The core layer (200) may include a first core (210) and a second core (220). The first core (210) and the second core (220) may protrude from the core layer (200). The first core (210) and the second core (220) may have a spiral shape in a planar view according to FIG. 1a. The first core (210) and the second core (220) may have a spiral shape having the same central axis. The center of the first core (210) and the second core (220) may have an S-shape. The thickness of the core layer (200) in the third direction (D3) may be 0.3 μm or more and 0.6 μm or less.

[0035] The core layer (200) may include a ferroelectric material. For example, the core layer (200) may include LiNbO3 or BaTiO3. The core layer (200) may include a ferroelectric material polarized in a third direction (D3). The third direction (D3) may intersect the first direction (D1) and the second direction (D2). For example, the third direction (D3) may be a vertical direction orthogonal to the first direction (D1) and the second direction (D2). The material being polarized in the third direction (D3) may mean, for example, that the polarization density is in the third direction (D3).

[0036] The first core (210) may include a ferroelectric material polarized in a third direction (D3). The second core (220) may include a ferroelectric material polarized in a direction different from that of the first core (210). The second core (220) may include a ferroelectric material polarized in the opposite direction to the third direction (D3).

[0037] The first core (210) may include a first straight section (210S1), a first curved section (210C1) connected to the first straight section (210S1), a connecting section (210CC) connected to the first curved section (210C1), a second curved section (210C2) connected to the connecting section (210CC), and a second straight section (210S2) connected to the second curved section (210C2). The first curved section (210C1) of the first core (210) may connect the first straight section (210S1) and the connecting section (210CC). The connecting section (210CC) of the first core (210) may connect the first curved section (210C1) and the second curved section (210C2). The second curved section (210C2) of the first core (210) can connect the second straight section (210S2) and the connecting section (210CC).

[0038] The first curved section (210C1) of the first core (210) may include a first part (210C11) and a second part (210C12) that are spaced apart from each other in a first direction (D1) with the second curved section (210C2) and the connecting section (210CC) in between. The second curved section (210C2) of the first core (210) may include a first part (210C21) and a second part (210C22) that are spaced apart from each other in a first direction (D1) with the connecting section (210CC) in between. The distance (DS1) between the first part (210C11) and the second part (210C12) of the first curved section (210C1) of the first core (210) may be greater than the distance (DS2) between the first part (210C21) and the second part (210C22) of the second curved section (210C2) of the first core (210).

[0039] The second core (220) may include a first straight section (220S1), a first curved section (220C1) connected to the first straight section (220S1), a connecting section (220CC) connected to the first curved section (220C1), a second curved section (220C2) connected to the connecting section (220CC), and a second straight section (220S2) connected to the second curved section (220C2). The first curved section (220C1) of the second core (220) may connect the first straight section (220S1) and the connecting section (220CC). The connecting section (220CC) of the second core (220) may connect the first curved section (220C1) and the second curved section (220C2). The second curved section (220C2) of the second core (220) can connect the second straight section (220S2) and the connecting section (220CC).

[0040] The first curved section (220C1) of the second core (220) may include a first part (220C11) and a second part (220C12) that are spaced apart from each other in a first direction (D1) with the second curved section (220C2) and the connecting section (220CC) in between. The second curved section (220C2) of the second core (220) may include a first part (220C21) and a second part (220C22) that are spaced apart from each other in a first direction (D1) with the connecting section (220CC) in between. The distance between the first part (220C11) and the second part (220C12) of the first curved section (220C1) of the second core (220) may be greater than the distance between the first part (220C21) and the second part (220C22) of the second curved section (220C2) of the second core (220).

[0041] The connecting portion (210CC) of the first core (210) and the connecting portion (220CC) of the second core (220) may have an S-shape in a planar view according to FIG. 1a.

[0042] An upper cladding (UC) may be provided on the core layer (200). The upper cladding (UC) may cover the core layer (200). The upper cladding (UC) may cover the first core (210) and the second core (220). A portion of the upper cladding (UC) may be placed between the first core (210) and the second core (220). The upper cladding (UC) may include an insulating material. The upper cladding (UC) may include the same material as the lower cladding (LC). The upper cladding (UC) and the lower cladding (LC) may include a material with a lower refractive index than that of the core layer (200). The thickness of the upper cladding (UC) in the third direction (D3) may be 1 μm or more and 3 μm or less. The thickness of the upper cladding (UC) in the third direction (D3) may be smaller than the thickness of the lower cladding (LC) in the third direction (D3).

[0043] An upper electrode (UE) may be placed on the upper cladding (UC). The upper electrode (UE) may overlap the first core (210) and the second core (220) in a third direction (D3). The upper electrode (UE) may have a spiral shape in a planar view according to FIG. 1a. The upper electrode (UE) may have a spiral shape having the same central axis as the first core (210) and the second core (220). The center of the upper electrode (UE) may have an S-shape. The thickness of the upper electrode (UE) in the third direction (D3) may be 0.3 μm or more and 1.5 μm or less. The thickness of the upper electrode (UE) in the third direction (D3) may be the same as the thickness of the lower electrode (LE) in the third direction (D3).

[0044] The upper electrode (UE) may include a first portion (UE1) that overlaps in a third direction (D3) with the first curved portion (210C1) of the first core (210) and the first curved portion (220C1) of the second core (220). The upper electrode (UE) may include a second portion (UE2) that overlaps in a third direction (D3) with the second curved portion (210C2) of the first core (210) and the second curved portion (220C2) of the second core (220). The width of the first portion (UE1) and the second portion (UE2) of the upper electrode (UE) in the first direction (D1) may be 5 μm or more and 15 μm or less. The distance between adjacent first portions (UE1) and second portions (UE2) of the upper electrode (UE) may be 5 μm or more and 15 μm or less.

[0045] The upper electrode (UE) may include an end portion (UE_E). The upper electrode (UE) may include a pair of terminal portions (UE_G) spaced apart from each other in a second direction (D2) with the end portion (UE_E) in between. The terminal portion (UE_G) of the upper electrode (UE) may be in contact with the lower electrode (LE). The end portion (UE_E) of the upper electrode (UE) and the pair of terminal portions (UE_G) may be GSG ports.

[0046] The first straight section (210S1) of the first core (210) and the first straight section (220S1) of the second core (220) can be connected to the first distribution section (BS1). The second straight section (210S2) of the first core (210) and the second straight section (220S2) of the second core (220) can be connected to the second distribution section (BS2).

[0047] The first straight section (210S1) of the first core (210), the first straight section (220S1) of the second core (220), the second straight section (210S2) of the first core (210), and the second straight section (220S2) of the second core (220) may not overlap with the upper electrode (UE) in the third direction (D3).

[0048] The first distribution unit (BS1) can be connected to the first input waveguide (IW1) and the second input waveguide (IW2). The second distribution unit (BS2) can be connected to the first output waveguide (OW1) and the second output waveguide (OW2).

[0049] Referring to FIGS. 1c and 1d, the upper electrode (UE) and the lower electrode (LE) can come into contact with each other. The lower cladding (LC) may include a first inclined surface (LC_S1). The core layer (200) may include a first inclined surface (200S1). The upper cladding (UC) may include a first inclined surface (UC_S1). The upper electrode (UE) can cover the first inclined surface (LC_S1) of the lower cladding (LC), the first inclined surface (200S1) of the core layer (200), and the first inclined surface (UC_S1) of the upper cladding (UC). The upper electrode (UE) can come into contact with the lower electrode (LE) by penetrating the lower cladding (LC), the core layer (200), and the upper cladding (UC).

[0050] The lower cladding (LC) may include a second inclined surface (LC_S2). The core layer (200) may include a second inclined surface (200S2). The upper cladding (UC) may include a second inclined surface (UC_S2). The upper electrode (UE) may cover the second inclined surface (LC_S2) of the lower cladding (LC), the second inclined surface (200S2) of the core layer (200), and the second inclined surface (UC_S2) of the upper cladding (UC).

[0051] The upper electrode (UE) may include a third part (UE3) and a fourth part (UE4) spaced apart from each other in a first direction (D1). The fourth part (UE4) of the upper electrode (UE) may be in contact with the lower electrode (LE). A resistive layer (RE) connecting the third part (UE3) and the fourth part (UE4) of the upper electrode (UE) may be provided. The resistive layer (RE) may include a material having a higher resistivity than the upper electrode (UE).

[0052] An optical device according to some embodiments may include a first core (210) and a second core (220) comprising materials polarized in different directions. Accordingly, when an electrical signal is applied to the upper electrode (UE), the first core (210) and the second core (220) may perform optical phase modulation operations in different directions.

[0053] An optical device according to some embodiments may comprise a Mach-Zehnder interferometer including a first core (210), a second core (220), a first distribution unit (BS1), and a second distribution unit (BS2).

[0054] In some embodiments, the optical device may have a lower electrode (LE) and an upper electrode (UE) that overlap each other in a third direction (D3). Accordingly, the integration density of the optical device can be improved, and miniaturization can be facilitated.

[0055] In some embodiments, the optical device may have a first core (210) and a second core (220) in a spiral shape. Accordingly, the integration density of the optical device may be improved, and miniaturization may be easy.

[0056]

[0057] FIGS. 2a and 2b are drawings illustrating the operation of an optical device according to some embodiments. FIG. 2b is a cross-sectional view along the line IV-IV' of FIG. 2a.

[0058] Referring to FIGS. 2a and 2b, a first input light (IL1) can be input through a first input waveguide (IW1). The first input light (IL1) can be distributed into a first forward light (TL1) and a second forward light (TL2) by a first distribution unit (BS1). The first and second forward lights (TL1, TL2) can have the same intensity. The first forward light (TL1) can be driven through a first core (210). The second forward light (TL2) can be driven through a second core (220).

[0059] When the first and second traveling lights (TL1, TL2) travel through the first and second cores (210, 220), an electric field (EF) may be formed between the upper electrode (UE) and the lower electrode (LE). The refractive index of the first core (210) and the second core (220) may change due to the electric field (EF). Accordingly, the phase of the first traveling light (TL1) and the second traveling light (TL2) may change.

[0060] As the polarization directions of the first core (210) and the second core (220) are different, the changes in the refractive index of the first core (210) and the second core (220) may differ. For example, the refractive index of the first core (210) may change by +Δn in the third direction (D3), and the refractive index of the second core (220) may change by -Δn in the third direction (D3). Under the same electric field, the changes in the refractive index experienced by light traveling through the first core (210) and the second core (220) may be in opposite directions. Accordingly, the optical modulator of the Mach-Zehnder interferometer substrate may perform a push-pull operation. As the changes in the refractive index of the first core (210) and the second core (220) differ, the phase change of the first traveling light (TL1) and the phase change of the second traveling light (TL2) may differ.

[0061] The first traveling light (TL1) and the second traveling light (TL2) that have passed through the first core (210) and the second core (220) can pass through the second distribution unit (BS2) and be distributed into the first output light (OL1) and the second output light (OL2). The first output light (OL1) and the second output light (OL2) can have the same intensity.

[0062] The second input tube (IL2) can operate in a manner similar to the first input light (IL1).

[0063]

[0064] FIG. 3a shows the relative values ​​of the reflection intensity of an RF signal flowing through the upper and lower electrodes of an optical device according to some embodiments as a function of frequency. FIG. 3b shows the relative values ​​of the transmission intensity of an RF signal flowing through the upper and lower electrodes of an optical device according to some embodiments as a function of frequency. FIG. 3c is a graph showing the impedance between the upper and lower electrodes of an optical device according to some embodiments as a function of frequency. FIG. 3d is a graph showing the group refractive index of an RF signal of an optical device according to some embodiments as a function of frequency.

[0065] The width of the first part (UE1) and the second part (UE2) of the upper electrode (UE) in the first direction (D1) is set to 10 μm, the length of the spiral part of the upper electrode (UE) is set to 2.1 mm, and the distance between the first part (UE1) and the second part (UE2) of the upper electrode (UE) that are adjacent to each other is set to 10 μm. The substrate (100) contains Si, the lower cladding (LC) and the upper cladding (UC) contain SiO2, and the core layer (200) contains LiNbO3.

[0066] Referring to Figures 3a and 3b, it was confirmed that the strength of the reflected signal was relatively low at -10dB in the frequency band greater than 0GHz and less than 200GHz, and the strength of the incident signal showed a loss of 6dB or less around 200GHz.

[0067] Referring to Fig. 3c, it was confirmed that the impedance is 40Ω to 45Ω for high-frequency signals.

[0068] Referring to Fig. 3d, it was confirmed that the group refractive index of the RF signal matches the group refractive index of the optical signal with a difference of 5% to 10%.

[0069] It was confirmed that the optical device according to some embodiments is capable of operating at ultra-high speeds at high frequencies.

[0070]

[0071] FIGS. 4a, 4b, 4c, 4d, 4e, 4f, and 4g are drawings illustrating a method for manufacturing an optical device according to some embodiments.

[0072] Referring to FIG. 4a, a substrate (100) may be provided.

[0073] Referring to FIG. 4b, a lower electrode (LE) can be formed on the substrate (100).

[0074] Referring to Fig. 4c, a lower cladding (LC) can be formed on the lower electrode (LE).

[0075] Referring to FIG. 4d, a core layer (200) can be formed on the lower cladding (LC). The core layer (200) may include a polarized ferroelectric material.

[0076] Referring to FIG. 4e, a poling electrode (SE) can be formed on the core layer (200). The poling electrode (SE) may have a spiral shape in a planar view according to FIG. 1a. The center of the poling electrode (SE) may have an S-shape in a planar view according to FIG. 1a. The poling electrode (SE) may have a shape similar to the second core (220) described in FIG. 1a in a planar view according to FIG. 1a.

[0077] The poling electrode (SE) can be superimposed on the first part (201) of the core layer (200) in the third direction (D3). Voltage can be applied to the lower electrode (LE) and the poling electrode (SE). When voltage is applied to the lower electrode (LE) and the poling electrode (SE), an electric field can be formed within the first part (201) of the core layer (200). Due to the electric field formed within the first part (201) of the core layer (200), the polarization direction of the first part (201) of the core layer (200) can be opposite to that of other parts of the core layer (200).

[0078] Referring to FIG. 4f, the poling electrode (SE) can be removed. A portion of the core layer (200) can be etched. A portion of the core layer (200) can be etched to form a protruding portion. The protruding portion of the core layer (200) can be defined as a first core (210) or a second core (220).

[0079] Referring to FIG. 4g, an upper cladding (UC) can be formed on the core layer (200).

[0080] Referring to FIGS. 1a, 1b, 1c and 1d, a first input waveguide (IW1), a second input waveguide (IW2), a first output waveguide (OW1), a second output waveguide (OW2), a first distribution section (BS1), and a second distribution section (BS2) can be formed on a substrate (100). A resistance layer (RE) connected to a first upper electrode (UE) can be formed.

[0081]

[0082] FIGS. 5a, 5b, 5c, 5d, 5e, and 5f are drawings illustrating a method for manufacturing an optical device according to some embodiments. The method for manufacturing an optical device according to FIGS. 5a, 5b, 5c, 5d, 5e, and 5f may be similar to the method for manufacturing an optical device according to FIGS. 4a, 4b, 4c, 4d, 4e, 4f, and 4g, except as described below.

[0083] Referring to FIG. 5a, a substrate (100) may be provided. A lower electrode (LE) may be formed on the substrate (100). A lower cladding (LC) may be formed on the lower electrode (LE). A core layer (200) may be formed on the lower cladding (LC).

[0084] Referring to FIG. 5b, a portion of the core layer (200) can be etched. A portion of the core layer (200) can be etched to form a protruding portion. The protruding portion of the core layer (200) can be defined as a first core (210) and a second core (220).

[0085] Referring to FIG. 5c, an upper cladding (UC) can be formed on the core layer (200).

[0086] Referring to FIG. 5d, a poling electrode (SEa) can be formed on the upper cladding (UC). The poling electrode (SEa) can be overlapped with the second core (220) in the third direction (D3). The poling electrode (SEa) may be similar to that described in FIG. 4e, except otherwise described.

[0087] Referring to FIG. 5e, voltage can be applied to the poling electrode (SEa) and the lower electrode (LE). When voltage is applied to the poling electrode (SEa) and the lower electrode (LE), an electric field can be formed within the second core (220). Due to the electric field formed within the second core (220), the polarization direction of the second core (220) can be different from that of the first core (210).

[0088] Referring to FIG. 5f, the polling electrode (SEa) may be removed. A signal electrode that transmits an electrical signal may be formed. In some embodiments, the signal electrode may be an upper electrode (UE, FIG. 1a). Referring to FIG. 1a, 1b, 1c and 1d, a first input waveguide (IW1), a second input waveguide (IW2), a first output waveguide (OW1), a second output waveguide (OW2), a first distribution section (BS1) and a second distribution section (BS2) may be formed on the substrate (100). A resistive layer (RE) connected to the first upper electrode (UE) may be formed.

[0089]

[0090] FIG. 6 is a drawing showing an optical device according to some embodiments. The optical device according to FIG. 6 may be similar to the optical device according to FIG. 1a, 1b, 1c and 1d, except as described below.

[0091] Referring to FIG. 6, the first core (210b) may include a first straight section (210S1b), a second straight section (210S2b), a third straight section (210S3b), a fourth straight section (210S4b), and a fifth straight section (210S5b). The first core (210b) may include a first curved section (210C1b) connecting the first straight section (210S1b) and the second straight section (210S2b), a second curved section (210C2b) connecting the second straight section (210S2b) and the third straight section (210S3b), a third curved section (210C3b) connecting the third straight section (210S3b) and the fourth straight section (210S4b), and a fourth curved section (210C4b) connecting the fourth straight section (210S4b) and the fifth straight section (210S5b).

[0092] The first straight section (210S1b), the third straight section (210S3b), and the fifth straight section (210S5b) of the first core (210b) may have a straight line shape extending in the second direction (D2). The second straight section (210S2b) and the fourth straight section (210S4b) of the first core (210b) may have a straight line shape extending in the first direction (D1). The fifth straight section (210S5b) of the first core (210b) may be positioned between the first straight section (210S1b) and the third straight section (210S3b). The first to fourth curved sections (210C1b, 210C2b, 210C3b, 210C4b) of the first core (210b) may have an Euler bend curve shape.

[0093] The second core (220b) may have a shape similar to the first core (210b). The second core (220b) may include straight sections and curved sections, and the curved sections of the second core (220b) may have the shape of an Euler bend curve. The upper electrode (UEb) may include straight sections and curved sections, and the curved sections of the upper electrode (UEb) may have the shape of an Euler bend curve. The Euler bend curve may have the same dimensions without change in curvature.

[0094] An optical device according to some embodiments may include curved portions in which the first core (210b) and the second core (220b) have the shape of an Euler bend curve, thereby reducing the change in the polarization direction of light passing through the first core (210b) and the second core (220b).

[0095] An optical device according to some embodiments may have a first core (210b) and a second core (220b) that include a spiral shape comprising straight sections, thereby making the straight sections longer and the curved sections smaller. Accordingly, the change in the polarization direction of light passing through the first core (210b) and the second core (220b) can be reduced.

[0096]

[0097] FIG. 7 is a drawing showing an optical device according to some embodiments. The optical device according to FIG. 7 may be similar to the optical device according to FIG. 1a, 1b, 1c and 1d, except as described below.

[0098] Referring to FIG. 7, a first heater (HT1), a second heater (HT2), and a third heater (HT3) may be provided. The first to third heaters (HT1, HT2, HT3) may include a first heating electrode (HE1), a second heating electrode (HE2), and a heating resistor (HE_R) connecting the first and second heating electrodes (HE1, HE2).

[0099] The first heater (HT1) may be adjacent to the first distribution section (BS1). The second heater (HT2) may be adjacent to the second distribution section (BS2). The third heater (HT3) may be adjacent to the second straight section (220S2) of the second core (220) or the second straight section (210S2) of the first core (210).

[0100] A voltage can be applied between the first heating electrode (HE1) and the second heating electrode (HE2). Accordingly, current can flow through the heating resistor (HE_R), and accordingly, heat can be generated in the heating resistor (HE_R).

[0101] The first distribution section (BS1) may be heated by heat generated from the first heater (HT1). As the first distribution section (BS1) is heated, the refractive index of the first distribution section (BS1) may change. The second distribution section (BS2) may be heated by heat generated from the second heater (HT2). As the second distribution section (BS2) is heated, the refractive index of the second distribution section (BS2) may change.

[0102] The second straight section (220S2) of the second core (220) can be heated by the heat generated from the third heater (HT3). As the second straight section (220S2) of the second core (220) is heated, the refractive index of the second straight section (220S2) of the second core (220) can change.

[0103] An optical device according to some embodiments may heat a first distribution unit (BS1) and a second distribution unit (BS2) to change the refractive index of the first distribution unit (BS1) and the second distribution unit (BS2). As the refractive index of the first distribution unit (BS1) and the second distribution unit (BS2) changes, the light distribution intensity of the first distribution unit (BS1) and the second distribution unit (BS2) can be adjusted.

[0104] An optical device according to some embodiments can heat the second core (220) to change the refractive index of the second core (220). As the refractive index of the second core (220) changes, a phase change can be performed stably.

[0105]

[0106] FIG. 8 is a drawing showing an optical device according to some embodiments. The optical device according to FIG. 8 may be similar to the optical device according to FIG. 1a, 1b, 1c and 1d, except as described below.

[0107] Referring to FIG. 8, the first distribution unit (BS1) and the second distribution unit (BS2) may be positioned between the first and second input waveguides (IW1, IW2) and the first and second output waveguides (OW1, OW2).

[0108] The first distribution unit (BS1) and the second distribution unit (BS2) may be spaced apart from each other in the first direction (D1). The first and second input waveguides (IW1, IW2) and the first and second output waveguides (OW1, OW2) may be spaced apart from each other in the first direction (D1).

[0109] The first core (210c) and the second core (220c) may be spaced apart from each other in the second direction (D2). The central axis of the first core (210c) and the central axis of the second core (220c) may be spaced apart from each other in the second direction (D2).

[0110] A polarization region (PR) may be defined in a core layer (200) having polarized characteristics, and a second core (220c) may be placed on the polarization region (PR). The region of the core layer (200) excluding the polarization region (PR) is polarized in a third direction (D3), and the polarization region (PR) may be a region polarized in the opposite direction to the third direction (D3).

[0111] The upper electrode (UEc) may include a first part (UE1c) that overlaps the first core (210c) in a third direction (D3) and a second part (UE2c) that overlaps the second core (220c) in a third direction (D3). The first part (UE1c) and the second part (UE2c) of the upper electrode (UEc) may be spaced apart from each other in a second direction (D2). The first part (UE1c) and the second part (UE2c) of the upper electrode (UEc) may have a spiral shape. The central axis of the first part (UE1c) of the upper electrode (UEc) may be the same as the central axis of the first core (210c). The central axis of the second part (UE2c) of the upper electrode (UEc) may be the same as the central axis of the second core (220c).

[0112] A pair of first terminal portions (UE_G1c) may be arranged spaced apart from each other in a second direction (D2) with a first end portion (UE_E1c) connected to a first portion (UE1c) of the upper electrode (UEc). The first terminal portions (UE_G1c) may be an exposed part of the upper electrode (UEc).

[0113] A pair of second terminal portions (UE_G2c) may be arranged spaced apart from each other in a second direction (D2) with a second end portion (UE_E2c) connected to a second portion (UE2c) of the upper electrode (UEc). The second terminal portions (UE_G2c) may be an exposed portion of the upper electrode (UEc). The first and second terminal portions (UE_G1c, UE_G2c) of the upper electrode (UEc) may be connected to the lower electrode (LE) similarly to FIG. 1c.

[0114] A resistance layer (RE) can be connected to the first part (UE1c) and the second part (UE2c) of the upper electrode (UEc), respectively. Each of the first part (UE1c) and the second part (UE2c) of the upper electrode (UEc) can be connected to the lower electrode (BE) through the resistance layer (RE).

[0115]

[0116] FIG. 9 is a drawing showing an optical device according to some embodiments. The optical device according to FIG. 9 may be similar to the optical device according to FIG. 8, except for what is described below.

[0117] Referring to FIG. 9, the first part (UE1d) and the second part (UE2d) of the upper electrode (UEd) can be connected to each other through the end (UE_Ed). The first part (UE1d) and the second part (UE2d) of the upper electrode (UEd) can be connected to each other through a connecting resistor (CR). A pair of terminal parts (UE_Gd) can be provided that are spaced apart from each other in a second direction (D2) with the end (UE_Ed) of the upper electrode (UEd) in between. The end (UE_Ed) of the upper electrode (UEd) can be split into a first part (UE_E1d) connected to the first upper electrode (UE1d) and a second part (UE_E2d) connected to the second upper electrode (UE2d). The impedance of the first part (UE_E1d) and the impedance of the second part (UE_E2d) of the upper electrode (UEd) can be matched through a resistor (CR). The first part (UE_E1d) and the second part (UE_E2d) of the end (UE_Ed) of the upper electrode (UEd) can distribute electrical signals in a 1:1 ratio, and the distributed electrical signals can have the same phase.

[0118]

[0119] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Lower electrode; Lower cladding on the lower electrode above; A first input waveguide, a second input waveguide, a first distributor, a first output waveguide, a second output waveguide, a second distributor, a first core, and a second core on the lower cladding above; Upper cladding covering the first and second cores; and It includes an upper electrode on the upper cladding above, and The first input waveguide, the second input waveguide, the first core, and the second core are connected to the first distribution unit, and The first output waveguide, the second output waveguide, the first core, and the second core are connected to the second distribution unit, and The lower electrode, the first core, and the upper electrode are vertically overlapped with each other, and The lower electrode, the second core, and the upper electrode are vertically overlapped with each other, and An optical device in which the polarization direction of the first core and the polarization direction of the second core are opposite to each other.

2. In Paragraph 1, An optical device in which the first core, the second core, and the upper electrode have a spiral shape or a straight shape.

3. In Paragraph 1, The first core and the second core are optical devices comprising a ferroelectric material.

4. In Paragraph 1, Each of the first core and the second core includes straight sections and curved sections, and The above curved sections are optical devices having the shape of Euler bend curves.

5. In Paragraph 4, An optical device in which the length of each of the above straight sections is greater than the length of each of the above curved sections.

6. In Paragraph 1, A first heater that changes the refractive index of the first distribution section; and An optical device further comprising a second heater that changes the refractive index of the second distribution section.

7. In Paragraph 6, An optical device further comprising a third heater that changes the refractive index of the first core or the second core.

8. In Paragraph 1, The upper electrode is an optical device comprising a first portion vertically overlapping with the first core and a second portion vertically overlapping with the second core.

9. In Paragraph 8, A polarization region is defined in which the second part of the second core and the upper electrode is disposed, and An optical device in which the first part of the first core and the upper electrode is spaced apart from the polarization region.

10. Substrate; Lower electrode on the above substrate; Lower cladding on the lower electrode above; A first core and a second core on the lower cladding above; Upper cladding covering the first and second cores; and It includes an upper electrode on the upper cladding above, and The lower electrode, the first core, and the upper electrode are vertically overlapped with each other, and The lower electrode, the second core, and the upper electrode are vertically overlapped with each other, and An optical device comprising a first core and a second core that are polarized in opposite directions.

11. In Paragraph 10, The first core and the second core are optical devices that are polarized in opposite directions.

12. In Paragraph 10, The upper electrode includes a first portion vertically overlapping with the first core and a second portion vertically overlapping with the second core, and An optical device in which the first part and the second part of the upper electrode are connected to each other through a connecting resistor.

13. In Paragraph 12, The above upper electrode is an optical device further comprising an end connected to the first part and the second part.

14. In Paragraph 10, The first core and the second core are optical devices comprising LiNbO3.

15. In Paragraph 10, Each of the first and second cores is an optical device having a spiral shape.

16. In Paragraph 10, The first core above includes a curved portion, and The curved portion of the first core has the shape of an Euler bend curve in an optical device.

17. In Paragraph 10, An optical device in which a portion of the upper cladding is disposed between the first core and the second core.

18. Forming a lower electrode on a substrate; Forming a lower cladding on the lower electrode above; Forming a core layer comprising a ferroelectric material polarized in a first direction on the lower cladding above; Forming a poling electrode that overlaps with the core layer; and A method for manufacturing an optical device comprising applying a voltage to the lower electrode and the poling electrode to change the polarization direction of a first portion of the core layer.

19. In Paragraph 18, Removing the above-mentioned poling electrode; Forming an upper cladding on the core layer; and A method for manufacturing an optical device further comprising forming an upper electrode on the upper cladding.

20. In Paragraph 19, Before forming the upper cladding above, A method for manufacturing an optical device further comprising etching a portion of the core layer to form a first protrusion having a spiral shape and a second protrusion having a spiral shape.

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