Electro-optical modulator

Abstract

The invention provides an electro-optical modulator, which is applied to the technical field of optical fiber communication, and comprises an input optical waveguide used for optical signal injection; the first coupler is used for equally dividing the optical signal into two beams of optical signals with equal power; the phase modulation arm is used for changing the phase of the optical signal; wherein the phase modulation arm is provided with a phase change material, and the phase change material is reversibly converted between a crystalline state and an amorphous state; the traveling wave electrodes are arranged on the two sides of the phase modulation arm and used for changing the refractive index in the phase modulation arm under the action of an electric field; the second coupler is used for combining the interference light output by the phase modulation arm; and the output optical waveguide is used for outputting the interference light after beam combination. According to the electro-optical modulator, the phase-change material is arranged on the branch waveguide, and the phase-change material is reversibly converted between a crystalline state and an amorphous state by applying pulsed light, so that the light intensity passing through the branch is changed, the modulation function is dynamically switchable, and the functionality of a single modulator is effectively improved.

Description

Technical Field

[0001] The present disclosure relates to the field of optical fiber communication, and more particularly to an electro-optic modulator. Background Art

[0002] As the core device of microwave photons, electro-optic modulators have a wide range of applications. They are mainly divided into two categories: intensity modulators and phase modulators, each of which plays a unique and important role in different application scenarios. First, the intensity modulator changes the intensity of the light passing through the device by adjusting the intensity of the electric field, thereby achieving intensity modulation of the optical signal. This modulation method is a common means in optical communications and is used to transmit digital information. By controlling the input electrical signal of the modulator, the switching, modulation and encoding of the optical signal can be achieved, and the information can be transmitted in the form of light. Secondly, the phase modulator shows great application potential in fields such as laser radar and optical imaging. By adjusting the phase of the light wave, the phase modulator can achieve precise control of the optical signal so that it forms a specific phase pattern during the propagation process. This feature is widely used in laser radar, which can achieve high-resolution target detection and tracking and improve the performance of the laser radar system.

[0003] In practical applications, some scenarios require the use of both phase modulators and intensity modulators to meet different needs. For example, some communication systems may need to dynamically adjust the phase and intensity of the signal during transmission to adapt to complex communication environments. Traditional electro-optic modulators usually adopt intensity modulation or phase modulation designs, which cannot be dynamically switched within the same device, limiting their ability to adapt to different application scenarios. As the demand for flexibility and adaptability in communication systems continues to increase, an electro-optic modulator that can dynamically switch modulation types in different working scenarios has become an innovation that the market urgently needs. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The present disclosure provides an electro-optic modulator for at least partially solving one of the above-mentioned technical problems.

[0006] (II) Technical solution

[0007] The disclosed embodiment provides an electro-optic modulator method, including: an input optical waveguide for optical signal injection; a first coupler for dividing the optical signal into two optical signal beams with equal power; a phase modulation arm for changing the phase of the optical signal; wherein a phase change material is provided on the phase modulation arm, and the phase change material can be reversibly converted between a crystalline state and an amorphous state; traveling wave electrodes are provided on both sides of the phase modulation arm, and are used to change the refractive index in the phase modulation arm under the action of an electric field; a second coupler for combining the interference light output by the phase modulation arm; and an output optical waveguide for outputting the combined interference light.

[0008] According to an embodiment of the present disclosure, a phase modulation arm includes a first phase modulation arm and a second phase modulation arm.

[0009] According to an embodiment of the present disclosure, the traveling wave electrode includes a first traveling wave electrode and a second traveling wave electrode, which are respectively placed on both sides of the first phase modulation arm and the second phase modulation arm, wherein the traveling wave electrode consists of a ground electrode and a signal electrode.

[0010] According to an embodiment of the present disclosure, the first traveling wave electrode and the second traveling wave electrode share the same signal electrode, the signal electrode is placed in the middle area between the first phase modulation arm and the second phase modulation arm, the ground electrode of the first traveling wave electrode is placed on the other side of the first phase modulation arm corresponding to the signal electrode; the ground electrode of the second traveling wave electrode is placed on the other side of the second phase modulation arm corresponding to the signal electrode.

[0011] According to an embodiment of the present disclosure, the phase change material is disposed at any position in the second phase modulation arm except the traveling wave electrode.

[0012] According to an embodiment of the present disclosure, the electro-optic modulator further includes a control waveguide and a grating coupler, which are arranged at adjacent positions of the phase change material to control the reversible conversion of the phase change material between different crystalline states.

[0013] According to an embodiment of the present disclosure, a grating coupler is used to couple pulsed light to a control waveguide, and the control waveguide is used to inject the pulsed light into a phase change material to adjust the phase change material to a different crystalline state.

[0014] According to an embodiment of the present disclosure, an input optical waveguide, a first coupler, a first phase modulation arm, a second coupler, and an output optical waveguide are sequentially connected to form a first optical path; an input optical waveguide, a first coupler, a second phase modulation arm, a phase change material, a second coupler, and an output optical waveguide are sequentially connected to form a second optical path.

[0015] According to an embodiment of the present disclosure, when the phase change material is in a pure crystalline state, the light output of the second optical path is 0, and at this time, the electro-optical modulator is a phase modulator; when the phase change material is in an amorphous state, both the first optical path and the second optical path output light, and at this time, the electro-optical modulator is an intensity modulator.

[0016] According to an embodiment of the present disclosure, the first coupler and the second coupler are any one of a Y-branch coupler, a directional coupler, and a multi-mode interference coupler.

[0017] (III) Beneficial effects

[0018] The electro-optic modulator provided by the present disclosure has at least the following beneficial effects:

[0019] By setting a PCM material that can reversibly change between a crystalline state and an amorphous state in an electro-optic modulator, the electro-optic modulator can dynamically switch the modulation mode under different modulation requirements, thereby enriching the function and application scope of the electro-optic modulator. In addition, the electro-optic modulator provided by the present disclosure adopts a traveling wave electrode, and works based on a push-pull structure when the electro-optic modulator is switched to an intensity modulator working mode, which is conducive to achieving the characteristics of high modulation bandwidth and low half-wave voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0021] Figure 1 The structure of the electro-optic modulator in the embodiment of the present disclosure is schematically shown.

[0022] [Reference Signs]

[0023] 1-input optical waveguide; 21-first coupler; 22-second coupler; 3-ground electrode; 4-signal electrode; 5-phase change material; 6-control waveguide; 7-grating coupler; 8-output optical waveguide; 9-phase modulation arm. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present disclosure.

[0025] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0026] In the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0027] In the description of the present disclosure, it is necessary to understand that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0028] Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure. The shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual size, proportion, and actual positional relationship. In addition, in the claims, any reference symbol between brackets shall not be construed as a limitation to the claims.

[0029] Similarly, in order to simplify the present disclosure and help understand one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. The description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of the present disclosure, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] Figure 1 The structure of the electro-optic modulator in the embodiment of the present disclosure is schematically shown.

[0032] like Figure 1 As shown, the electro-optic modulator provided by the embodiment of the present disclosure includes: an input optical waveguide 1, a first coupler 21, a phase modulation arm 9, a traveling wave electrode, a second coupler 22 and an output optical waveguide 8.

[0033] The input optical waveguide 1 is used to introduce the optical signal into the electro-optic modulator.

[0034] The first coupler 21 is used to split the optical signal into a first optical signal and a second optical signal with equal power.

[0035] The phase modulation arm 9 is used to change the phase of the optical signal. The phase modulation arm 9 changes the phase of the optical signal based on the external electric field to achieve modulation of the optical signal. The phase modulation arm 9 can be an optical waveguide with a certain length.

[0036] Phase change material (PCM) is provided on the phase modulation arm 9. The PCM material has multiple different crystal states and can be reversibly converted between the crystal states based on different pulsed lights. By changing the crystal state of the PCM material, the light intensity passing through the phase modulation arm 9 is changed, and the electro-optic modulator is dynamically switched between different modulation types. Among them, the PCM material is usually a sulfur compound.

[0037] The traveling wave electrodes are arranged on both sides of the phase modulator arm 9, and are used to change the refractive index in the phase modulator arm 9 under the action of the electric field, so that the phase modulator arm 9 changes the phase of the optical signal. The traveling wave electrode is an electrode with a certain length, and the electrical signal can be transmitted along the electrode.

[0038] The change of the refractive index in the optical fiber can be controlled by applying voltage. When the voltage is applied to the traveling wave electrode, an electric field is generated in the phase modulation arm 9, causing the refractive index of the electro-optical material to change. The refractive index change will affect the propagation speed of the optical signal in the optical fiber, thereby changing the phase of the optical signal.

[0039] The second coupler 22 is used to combine the interference light after passing through the phase modulation arm 9.

[0040] The output optical waveguide 8 is used to output the combined interference light from the electro-optic modulator.

[0041] The electro-optic modulator provided by the present disclosure is provided with a phase change material 5 on a branch waveguide. By applying pulsed light, the phase change material 5 undergoes a reversible transformation between a crystalline state and an amorphous state, thereby changing the light intensity passing through the branch, achieving dynamic switching of the modulation mode of the modulator, and effectively improving the functionality of a single modulation device.

[0042] In some embodiments, the first coupler 21 and the second coupler 22 may be any one of a Y-branch coupler, a directional coupler, and a multi-mode interference coupler.

[0043] In some embodiments, the phase modulation arm 9 includes a first phase modulation arm and a second phase modulation arm, and the traveling wave electrode includes a first traveling wave electrode and a second traveling wave electrode, wherein the first traveling wave electrode is placed on both sides of the first phase modulation arm, and the second traveling wave electrode is placed on both sides of the second phase modulation arm.

[0044] In some embodiments, a material with a large electro-optic effect may be selected as the optical waveguide material, for example, lithium niobate or a polymer material with a large electro-optic coefficient.

[0045] In some embodiments, the traveling wave electrode is composed of a ground electrode 3 and a signal electrode 4, and the first traveling wave electrode and the second traveling wave electrode share the same signal electrode 4 to form a push-pull structure. The signal electrode 4 is placed in the middle area between the first phase modulation arm and the second phase modulation arm, the ground electrode 3 in the first traveling wave electrode is placed on the other side of the first phase modulation arm corresponding to the signal electrode 4, and the ground electrode 3 in the second traveling wave electrode is placed on the other side of the second phase modulation arm corresponding to the signal electrode 4.

[0046] In some embodiments, the phase change material 5 is disposed at any position in any phase modulation arm except the traveling wave electrode. Figure 1 As shown, in this embodiment, the phase change material 5 is disposed on the left side of the second phase modulation arm. Those skilled in the art may also adjust the position of the phase change material 5 according to actual needs, and the present disclosure does not limit this.

[0047] In some embodiments, the electro-optic modulator further includes a control waveguide 6 and a grating coupler 7. The control waveguide 6 and the grating coupler 7 are arranged at adjacent positions of the phase change material 5, and are used to control the reversible conversion of the phase change material 5 between different crystalline states. The grating coupler 7 is used to couple the pulse light into the chip, and the control waveguide 6 is used to inject the pulse light coupled by the grating coupler 7 into the PCM material to adjust the phase change material 5 to different crystalline states. Pulsed light with different pulse widths can cause the PCM material to reversibly convert between multiple crystalline states.

[0048] In some embodiments, the input optical waveguide 1, the first coupler 21, the first phase modulation arm, the second coupler 22, and the output optical waveguide 8 in the electro-optic modulator are connected in sequence to form a complete optical path, constituting a first branch (i.e., a first optical path). The input optical waveguide 1, the first coupler 21, the second phase modulation arm, the phase change material 5, the second coupler 22, and the output optical waveguide 8 are connected in sequence to form a complete optical path, constituting a second branch (i.e., a second optical path).

[0049] In some embodiments, after the optical signal is injected into the input optical waveguide 1, it is equally divided into a first optical signal and a second optical signal of equal power based on the first coupling coupler, the first optical signal propagates along the first optical path, and the second optical signal propagates along the second optical path. The phase change material 5 on the second optical path switches to different crystalline states in different scenarios, so that the modulation type of the electro-optic modulator is dynamically changed.

[0050] For example, when the phase change material is in a pure crystalline state, the absorption coefficient of the phase change material is 1, the light output of the second optical path is 0, and only the output light of the first optical path is fed into the output optical waveguide, that is, the output optical waveguide only outputs the interference light transmitted by the first optical path. At this time, the electro-optical modulator is a phase modulator.

[0051] When the phase change material is in an amorphous state, its absorption coefficient is 0, the output of the second optical path remains unchanged, and the output light of the first optical path and the second optical path is fed into the output optical waveguide. At this time, the electro-optic modulator is an intensity modulator, and the first traveling wave electrode and the second traveling wave electrode provide voltages of equal magnitude and opposite directions to form a push-pull structure, which is beneficial for the electro-optic modulator to achieve high modulation bandwidth and low half-wave voltage.

[0052] For another example, when the absorption coefficient of the phase change material is 0.5, the optical signal in the second optical path is not completely transmitted. At this time, the electro-optic modulator is an unequal modulator.

[0053] The disclosed embodiments achieve dynamic switching of the modulation mode of the electro-optic modulator under different modulation requirements by setting a PCM material that can reversibly transform between a crystalline state and an amorphous state in the electro-optic modulator, thereby enriching the function and application scope of the electro-optic modulator, providing a new idea for the preparation of more complex structures, and facilitating large-scale photonic integration.

[0054] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all be included in the scope of protection of the present disclosure.

Claims

1. An electro-optic modulator, characterized in that: include: An input optical waveguide (1) for injecting an optical signal; A first coupler (21), used for equally dividing the optical signal into two optical signals with equal power; A phase modulation arm (9) is used to change the phase of an optical signal; wherein a phase change material (5) is arranged on the phase modulation arm (9), and the phase change material (5) is reversibly convertible between a crystalline state and an amorphous state; Traveling wave electrodes are arranged on both sides of the phase modulation arm (9) and are used to change the refractive index in the phase modulation arm (9) under the action of an electric field; A second coupler (22) is used to combine the interference light output by the phase modulation arm (9); The output optical waveguide (8) is used to output the combined interference light.

2. The electro-optic modulator according to claim 1, characterized in that The phase modulation arm (9) comprises a first phase modulation arm and a second phase modulation arm.

3. The electro-optic modulator according to claim 2, characterized in that The traveling wave electrodes comprise a first traveling wave electrode and a second traveling wave electrode, which are respectively placed on both sides of the first phase modulation arm and on both sides of the second phase modulation arm, wherein the traveling wave electrodes consist of a ground electrode (3) and a signal electrode (4).

4. The electro-optic modulator according to claim 3, characterized in that The first traveling wave electrode and the second traveling wave electrode share the same signal electrode (4), the signal electrode (4) is placed in the middle area between the first phase modulation arm and the second phase modulation arm, the ground electrode (3) of the first traveling wave electrode is placed on the other side of the first phase modulation arm corresponding to the signal electrode (4); the ground electrode (3) of the second traveling wave electrode is placed on the other side of the second phase modulation arm corresponding to the signal electrode (4).

5. The electro-optic modulator according to claim 3, characterized in that: The phase change material (5) is arranged at any position in the second phase modulation arm except the traveling wave electrode.

6. The electro-optic modulator according to claim 5, characterized in that The electro-optic modulator further comprises a control waveguide (6) and a grating coupler (7), wherein the control waveguide (6) and the grating coupler (7) are arranged at adjacent positions of the phase change material (5) and are used to control the reversible conversion of the phase change material (5) between different crystalline states.

7. The electro-optic modulator according to claim 6, characterized in that The grating coupler (7) is used to couple the pulse light to the control waveguide (6), and the control waveguide (6) is used to inject the pulse light into the phase change material (5) to adjust the phase change material (5) to a different crystal state.

8. The electro-optic modulator according to claim 7, characterized in that: The input optical waveguide (1), the first coupler (21), the first phase modulation arm, the second coupler (22), and the output optical waveguide (8) are connected in sequence to form a first optical path; The input optical waveguide (1), the first coupler (21), the second phase modulation arm, the phase change material (5), the second coupler (22), and the output optical waveguide (8) are connected in sequence to form a second optical path.

9. The electro-optic modulator according to claim 8, characterized in that: When the phase change material (5) is in a pure crystalline state, the light output of the second light path is 0, and at this time, the electro-optic modulator is a phase modulator; When the phase change material (5) is in an amorphous state, both the first light path and the second light path output light, and at this time, the electro-optical modulator is an intensity modulator.

10. The electro-optic modulator according to claim 1, characterized in that: The first coupler (21) and the second coupler (22) are any one of a Y-branch coupler, a directional coupler, and a multi-mode interference coupler.

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