Phase modulation module and electro-optic modulator

Abstract

To reduce transmission losses and improve operational performance.SOLUTION: A phase modulation module has an input end face and an output end face, and comprises a substrate, an insulating layer, a waveguide layer, and an electrode layer that are arranged in order. The electrode layer includes a plurality of electrodes arranged by being spaced apart and constituted so as to form a modulation electric field region. The waveguide layer includes a plate layer, a first ridge layer, and a second ridge layer arranged in order in a direction to separate from the substrate. The plate layer extends to the input and the output end faces, the first ridge layer protrudes from the surface of the plate layer into a ridge form, extends to the input and the output end faces, and located in part to the modulation electric field region, and the second ridge layer protrudes from the surface of the first ridge layer into a ridge form, has an interval from each of the input and the output end faces, located in part in the modulation electric field region. The first and the second ridge layers form at least one waveguide arm that extends to the input and the output end faces and is modulated by the modulation electric field region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to the technical field of optical communications, and in particular to phase modulation modules and electro-optic modulators. [Background technology]

[0002] In recent years, with the rapid development of new network application services such as the Internet of Things, unmanned driving, telemedicine, and distance education, there has been an increasing demand for high-speed, high-capacity communication technologies. Optical communications has achieved rapid development in the direction of high-speed, high-capacity communication due to its characteristics such as wide bandwidth, high reliability, low cost, and strong anti-interference capabilities. The core research topic is how to load high-speed electrical signals onto optical carriers.

[0003] An electro-optic modulator is a modulator based on the electro-optic effect of electro-optic materials. The electro-optic effect means that when a voltage is applied to an electro-optic material, such as lithium niobate, gallium arsenide, or lithium tantalate crystal, the refractive index of the electro-optic material changes, resulting in a change in the properties of the light wave passing through the electro-optic material. Using the electro-optic effect, parameters such as the phase, amplitude, intensity, and polarization state of an optical signal can be modulated.

[0004] As the demand for high speed and large capacity communication technology continues to grow, the demand for low loss and performance of electro-optic modulators is increasing. Summary of the Invention

[0005] SUMMARY OF THE INVENTION Embodiments of the present disclosure provide a phase modulation module and an electro-optic modulator to reduce the transmission loss of the electro-optic modulator and improve the operating performance of the electro-optic modulator.

[0006] According to an aspect of the present disclosure, there is provided a phase modulation module having an input end face and an output end face, the phase modulation module comprising a substrate, an insulating layer, a waveguide layer, and an electrode layer arranged in that order, the electrode layer including a plurality of electrodes arranged at a distance from each other and configured to form a modulation field region, the waveguide layer including a plate layer, a first ridge layer, and a second ridge layer arranged in that order away from the substrate, the plate layer extending to the input end face and the output end face, the first ridge layer protruding in a ridge shape from a surface of the plate layer and extending to the input end face and the output end face, the first ridge layer being partially located in the modulation field region, the second ridge layer protruding in a ridge shape from the surface of the first ridge layer and spaced apart from each of the input end face and the output end face, the second ridge layer being partially located in the modulation field region, the second ridge layer and the first ridge layer forming at least one waveguide arm extending to the input end face and the output end face and modulated by the modulation field region.

[0007] In some embodiments, the second ridge layer includes a first variable width portion, a first constant width portion, and a second variable width portion connected in sequence in the longitudinal direction, the first constant width portion having a constant width everywhere, a portion of the first constant width portion being located in a modulated electric field region, the width direction being perpendicular to the longitudinal direction, and the width of the first variable width portion and the width of the second variable width portion each grading or gradually decreasing in a direction away from the first constant width portion.

[0008] In some embodiments, the first ridge layer includes a second constant width portion, a third variable width portion, a plate portion, a fourth variable width portion, and a third constant width portion connected in sequence in the longitudinal direction, wherein the second constant width portion has a constant width everywhere, the third constant width portion has a constant width everywhere, a portion of the plate portion is located in the modulated electric field region, and the widths of the third variable width portion and the fourth variable width portion each gradient or gradually decrease in a direction away from the plate portion.

[0009] In some embodiments, the plurality of electrodes includes a ground electrode and a signal electrode, and the second ridge layer and the first ridge layer form a single waveguide arm that is modulated by a modulated electric field region formed by the ground electrode and the signal electrode.

[0010] In some embodiments, the plurality of electrodes comprises a first electrode arranged in sequence. ground electrode, signal electrode, and a second ground The second ridge layer and the first ridge layer form two waveguide arms, one of the waveguide arms being a first ground Electrodes and signal The other waveguide arm is modulated by the modulation field region formed by the electrode, and the other waveguide arm is modulated by the second ground Electrodes and signal It is modulated by the modulating electric field field created by the electrodes.

[0011] In some embodiments, the plurality of electrodes includes a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode arranged in sequence, wherein the second ridge layer and the first ridge layer form two waveguide arms, one of the waveguide arms being modulated by a modulated electric field region formed by the first ground electrode and the first signal electrode, and the other waveguide arm being modulated by a modulated electric field region formed by the second ground electrode and the second signal electrode.

[0012] In some embodiments, at least a portion of the electrode layer is formed on the surface of the first ridge layer away from the substrate and does not overlap the second ridge layer, or at least a portion of the electrode layer is formed on the surface of the plate layer away from the substrate and does not overlap the first ridge layer and the second ridge layer, or at least a portion of the electrode layer is formed on the surface of the insulating layer away from the substrate and does not overlap the waveguide layer, or the phase modulation module further includes an insulating support layer located between the waveguide layer and the electrode layer, and at least a portion of the electrode layer is formed on the surface of the insulating support layer away from the substrate and does not overlap the second ridge layer.

[0013] In some embodiments, each waveguide arm includes at least one bend.

[0014] In some embodiments, the input end face and the output end face are located on two opposite sides of the phase modulation module, respectively, or the input end face and the output end face are located on the same side of the phase modulation module.

[0015] According to an aspect of the present disclosure, there is provided an electro-optic modulator comprising a phase modulation module according to any one of the above-described embodiments.

[0016] In some embodiments, the electro-optic modulator further comprises a first spot size conversion element and a second spot size conversion element, wherein the first spot size conversion element has a ridge waveguide structure and includes a diverging input end and a converging output end, the second spot size conversion element has a ridge waveguide structure and includes a converging input end and a diverging output end, and one of the at least one waveguide arm has one end coupled to the converging output end of the first spot size conversion element and the other end coupled to the converging input end of the second spot size conversion element.

[0017] In some embodiments, the second ridge layer and the first ridge layer form at least two waveguide arms, and the electro-optical modulator further comprises an optical splitting element and an optical combining element, wherein the optical splitting element has a ridge waveguide structure and includes a signal input end, a first split optical output end, and a second split optical output end, and the optical combining element has a ridge waveguide structure and includes the first split optical input end, the second split optical input end, and a signal output end, and two of the at least two waveguide arms are coupled at one end to the first split optical output end and the second split optical output end, respectively, and at the other end to the first split optical input end and the second split optical input end, respectively.

[0018] According to one or more embodiments of the present disclosure, the waveguide arm may be directly coupled to the ridge waveguide structure of another optical element without the need for an optical conversion element therebetween. After entering the waveguide arm, the light is transmitted through the single-layer structure of the first ridge layer, the two-layer structure composed of the first ridge layer and the second ridge layer, and then the single-layer structure of the first ridge layer. Therefore, by using the structural design of the first ridge layer and the second ridge layer, the spot can be flexibly and relatively moderately modulated. All of these are beneficial to reducing optical transmission loss and improving the coupling efficiency between the phase modulation module and other optical elements, thereby reducing the transmission loss of the electro-optic modulator and improving the operating performance of the electro-optic modulator.

[0019] These and other aspects of the disclosure will be apparent from and illustrated with reference to the embodiments described hereinafter.

[0020] Further details, features and advantages of the present disclosure are disclosed in the following description of exemplary embodiments, with reference to the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1] Figure 1 is a schematic diagram of the simplified structure of a conventional Mach-Zehnder modulator. [Figure 2] FIG. 2 is a schematic structural perspective view of a phase modulation module according to some embodiments of the present disclosure. [Figure 3] FIG. 3 is a schematic structural top view of a phase modulation module according to some embodiments of the present disclosure. [Figure 4] FIG. 4 is a schematic structural top view of a phase modulation module according to some embodiments of the present disclosure. [Figure 5] FIG. 5 is a schematic structural top view of a phase modulation module according to some embodiments of the present disclosure. [Figure 6] FIG. 6 is a schematic structural top view of an electro-optic modulator according to some embodiments of the present disclosure. [Figure 7]FIG. 7 is a schematic structural top view of an electro-optic modulator according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022]

[0033] The following briefly describes only some exemplary embodiments. As can be understood by those skilled in the art, the described embodiments can be modified in various ways without departing from the spirit or scope of the present disclosure. Accordingly, the accompanying drawings and description are to be regarded as illustrative in nature and not restrictive.

[0023] Currently, electro-optic modulation-related technologies have been widely developed and applied in fields such as optical communications, microwave photonics, laser beam deflection, and wavefront modulation. A Mach-Zehnder modulator is a type of electro-optic modulator in which an input optical signal is split into two branch optical signals, which then enter two waveguide arms. Each of the two waveguide arms is made of electro-optic material, and its refractive index changes with the applied modulation voltage. The change in the refractive index of the waveguide arms can change the phase of the branch optical signal. Therefore, the output from the convergence of the two branch optical signals is an interference signal whose intensity changes with the modulation voltage. Simply put, a Mach-Zehnder modulator can modulate different sidebands by controlling the modulation voltage applied to the two waveguide arms. As a device that converts electrical signals into optical signals, a Mach-Zehnder modulator is one of the core devices commonly used in optical interconnection, optical computing, and optical communication systems.

[0024] A simplified schematic diagram of a conventional Mach-Zehnder modulator is shown in Figure 1. Ideally, the Mach-Zehnder modulator 001 has two identical waveguide arms 02. When the Mach-Zehnder modulator 001 is not operating, neither of the two waveguide arms 02 experiences the electro-optic effect. Input light passes through the optical splitter element 01 and is then equally split into two branch optical signals. The two branch optical signals are still in phase after passing through the respective waveguide arms 02, and therefore, a coherent and reinforced signal for the two branch optical signals is output from the optical combiner element 05. When the Mach-Zehnder modulator 001 is operating, the electrodes 04 (e.g., including a signal electrode 040, a first ground electrode 041, and a second ground electrode 042) apply a modulation voltage to the two waveguide arms 02, and the two branch optical signals may differ in phase by an odd or even multiple of π after each of the two branch optical signals passes through one waveguide arm 02. When the phases of the two branch optical signals differ by an even multiple of π, the optical combining element 05 outputs a coherent reinforced signal for the two branch optical signals. When the phases of the two branch optical signals differ by an odd multiple of π, the optical combining element 05 outputs a coherent canceled signal for the two branch optical signals.

[0025] How to reduce the transmission loss of an electro-optical modulator and improve the operating performance of the electro-optical modulator is an urgent technical problem to be solved by those skilled in the art. Based on this, the embodiments of the present disclosure provide a phase modulation module and an electro-optical modulator.

[0026] As shown in FIG. 2 , a phase modulation module 100 provided in some embodiments of the present disclosure has an input end face 100a and an output end face 100b. The phase modulation module 100 includes, in order, a substrate 101, an insulating layer 102, a waveguide layer 103, and an electrode layer 104. The electrode layer 104 includes a plurality of electrodes 41 spaced apart and configured to form a modulation field region 42. The waveguide layer 103 includes a plate layer 31, a first ridge layer 32, and a second ridge layer 33, arranged in this order away from the substrate 101. The plate layer 31 extends to the input end face 100a and the output end face 100b. The first ridge layer 32 protrudes in a ridge shape from the surface of the plate layer 31 and extends to the input end face 100a and the output end face 100b, partially located in the modulation field region 42. The second ridge layer 33 protrudes in a ridge shape from the surface of the first ridge layer 32, is spaced apart from each of the input end face 100a and the output end face 100b, and is partially located in the modulation field region 42. The second ridge layer 33 and the first ridge layer 32 form at least one waveguide arm 30 that extends to the input end face 100a and the output end face 100b and can be modulated by the modulation field region 42.

[0027] The phase modulation module 100 is an important component of an electro-optic modulator that modulates an optical signal based on the electro-optic effect, and may be combined with other optical elements of the electro-optic modulator (such as a light splitter, a light combiner, and a spot-size converter). In an embodiment of the present disclosure, the input end face 100a and the output end face 100b of the phase modulation module 100 are each located on a side face of the phase modulation module 100. The side face of the phase modulation module 100 is adjacent to the bottom surface of the substrate 101.

[0028] Since the plate layer 31 extends generally in a planar shape, the phrase "the first ridge layer 32 protrudes in a ridge shape from the surface of the plate layer 31" may be understood to mean that the first ridge layer 32 is formed on the surface of the plate layer 31 and does not completely overlap with the plate layer 31, thereby presenting a structure protruding from the plate layer 31, i.e., the coverage area of ​​the first ridge layer 32 is less than the coverage area of ​​the plate layer 31. Similarly, the phrase "the second ridge layer 33 protrudes in a ridge shape from the surface of the first ridge layer 32" may be understood to mean that the second ridge layer 33 is formed on the surface of the first ridge layer 32 and does not completely overlap with the first ridge layer 32, thereby presenting a structure protruding from the first ridge layer 32, i.e., the coverage area of ​​the second ridge layer 33 is less than the coverage area of ​​the first ridge layer 32. The second ridge layer 33 and the first ridge layer 32 each include a portion located in the modulation field region 42, and the first ridge layer 32 extends to the input end face 100a and the output end face 100b, so that the second ridge layer 33 and the first ridge layer 32 can form at least one waveguide arm 30 that extends to the input end face 100a and the output end face 100b, can be modulated by the modulation field region 42, and is configured to guide light that is primarily transmitted therein.

[0029] The modulation field region 42 may be understood to refer to the region where an electric field is formed between the electrodes 41. The waveguide arm 30 is configured to mainly guide the light transmitted therein, but cannot absolutely restrict the transmission of the light therein. For example, some light may escape from the waveguide arm 30 to the plate layer 31 or even to the insulating layer 102. Therefore, reducing transmission loss and improving transmission stability are particularly important for the product performance of the electro-optic modulator.

[0030] Ridge waveguides generally have excellent properties such as a low fundamental mode cutoff frequency, a wide bandwidth, and low impedance. In the embodiment of the present disclosure, the waveguide layer 103 has a ridge waveguide structure and includes a plate layer 31, a first ridge layer 32, and a second ridge layer 33 arranged in that order. A portion of the waveguide arm 30 located in the modulated field region 42 has a two-layer structure (composed of a portion of the second ridge layer 33 and a portion of the first ridge layer 32), while a portion of the waveguide arm 30 near each of the input end face 100 a and the output end face 100 b has a single-layer structure (composed of a portion of the first ridge layer 32). With this design, the waveguide arm 30 can be directly coupled to the ridge waveguide structure of other optical elements (such as optical splitters, optical combiners, and spot-size converters) without the need for an optical conversion element between them. After entering the waveguide arm 30, light is transmitted through the single-layer structure of the first ridge layer 32, the two-layer structure composed of the first ridge layer 32 and the second ridge layer 33, and then the single-layer structure of the first ridge layer 32. Therefore, the structural design of the first ridge layer 32 and the second ridge layer 33 allows for flexible and relatively moderate spot modulation. All of this is beneficial to reducing optical transmission loss and improving the coupling efficiency between the phase modulation module 100 and other optical elements, thereby reducing the transmission loss of the electro-optic modulator and improving the operating performance of the electro-optic modulator.

[0031] 3 , in some embodiments of the present disclosure, the second ridge layer 33 includes a first variable width portion 331, a first constant width portion 332, and a second variable width portion 333, connected in sequence in the length direction. The first constant width portion 332 has a constant width everywhere, a portion of the first constant width portion 332 is located in the modulation field region 42, and the widths of the first variable width portion 331 and the second variable width portion 333 each slope or gradually decrease in a direction away from the first constant width portion 332. The width direction is perpendicular to the length direction.

[0032] In these embodiments, both ends of the longitudinally distributed first constant width portions 332 extend outside the modulated electric field region 42. In other embodiments of the present disclosure, one end of the longitudinally distributed first constant width portions may extend outside the modulated electric field region, but this is not specifically limited in the present disclosure.

[0033] Taking the first variable width portion 331 as an example, as shown in FIG. 3, the width of the first variable width portion gradually decreases in the direction away from the first constant width portion 332, and the two side edges (or one side edge) of the first variable width portion are formed obliquely (or may be curved) so that the width value decreases at any two positions along the length of the first variable width portion, the further away from the first constant width portion 332.

[0034] Taking the first variable width portion as an example, when the width of the first variable width portion decreases in a gradient away from the first constant width portion, at least one side edge of the first variable width portion is folded in. The first variable width portion 331 may be divided into at least two sections according to its width change rule, and the section farther from the first constant width portion 332 has a smaller average width.

[0035] First variable-width portion 331 and second variable-width portion 333 may each perform a relatively moderate spot size modulation on light transmitted into waveguide arm 30 before entering modulation field region 42 and after exiting modulation field region 42, so that the spot size of the transmitted light gradually changes (e.g., the spot size gradually increases or decreases), which is beneficial for reducing optical transmission loss. First constant-width portion 332 may perform a steady-state spot size modulation on the transmitted light that has passed through the modulation field, so that the spot size remains stable, which is beneficial for improving the stability of optical transmission.

[0036] In other embodiments of the present disclosure, the first variable width portion 331, the first constant width portion 332 and the second variable width portion 333 described above may adopt an overall constant width design instead of a variable width design.

[0037] 3 , in some embodiments of the present disclosure, the first ridge layer 32 includes, connected in sequence in the longitudinal direction, a second constant width portion 21, a third variable width portion 22, a plate portion 23, a fourth variable width portion 24, and a third constant width portion 25. The second constant width portion 21 has a constant width everywhere, the third constant width portion 25 has a constant width everywhere, a portion of the plate portion 23 is located in the modulation field region 42, and the widths of the third variable width portion 22 and the fourth variable width portion 24 each gradient or gradually decrease in a direction away from the plate portion 23.

[0038] In these embodiments, the two sides of the longitudinally distributed plate portions 23 both extend outside the modulated field region 42. In other embodiments of the present disclosure, it is also possible for one of the sides of the longitudinally distributed plate portions to extend outside the modulated field region, but this is not specifically limited to the present disclosure.

[0039] The second constant-width portion 21 and the third constant-width portion 25 may each perform steady-state spot size modulation on the transmitted light entering the waveguide arm 30 from the input end face 100 a and the transmitted light exiting the waveguide arm 30 from the output end face 100 b, thereby maintaining a stable spot size of the transmitted light, which is beneficial for improving the stability of optical transmission and further improving the coupling efficiency between the phase modulation module 100 and other optical elements. The third variable-width portion 22, in cooperation with the first variable-width portion 331, and the fourth variable-width portion 24, in cooperation with the second variable-width portion 333, can perform relatively moderate spot size modulation on the light transmitted to the waveguide arm 30 before entering the modulation field region 42 and after exiting the modulation field region 42, such that the spot size of the transmitted light gradually changes (e.g., the spot size gradually increases or decreases), which is beneficial for reducing optical transmission loss.

[0040] In other embodiments of the present disclosure, the second constant width portion 21, the third variable width portion 22, the plate portion 23, the fourth variable width portion 24 and the third constant width portion 25 described above may adopt an overall constant width design instead of a variable width design.

[0041] 2 , at least a portion (which may be a part or all) of the electrode layer 104 is formed on the surface of the first ridge layer 32 away from the substrate 101 and does not overlap the second ridge layer 33. The first ridge layer 32 may include a plate portion 23 extending in a planar shape, and at least a portion of the electrode layer 104 is formed on the surface of the plate portion 23.

[0042] In some embodiments of the present disclosure, at least a portion of the electrode layer may alternatively be formed on a surface of the plate layer remote from the substrate and does not overlap the first ridge layer and the second ridge layer.

[0043] In some embodiments of the present disclosure, at least a portion of the electrode layer may alternatively be formed on a surface of the insulating layer remote from the substrate and not overlap the waveguide layer.

[0044] In some embodiments of the present disclosure, the phase modulation module may further include an insulating support layer (not shown) located between the waveguide layer and the electrode layer, wherein at least a portion of the electrode layer is formed on a surface of the insulating support layer away from the substrate and does not overlap the second ridge layer.

[0045] The electrode layer 104 may have the same set height everywhere (i.e., the distance between the electrode layer 104 and the substrate 101), or may have different set heights in different parts. For example, a part of the electrode layer 104 that serves as a ground electrode and a part that serves as a signal electrode may be provided at different heights by using the above-mentioned design, thereby facilitating flexible regulation and design of electrical signal transmission using this height difference, and the difference in transmission speed between optical signals and electrical signals can be reduced, so that the two are well matched.

[0046] The specific number and arrangement of the electrodes 41 are not limited. As shown in Figure 3, in some embodiments of the present disclosure, the multiple electrodes 41 include a ground electrode 411 and a signal electrode 412, and the second ridge layer 33 and the first ridge layer 32 form a single waveguide arm 30 that is modulated by the modulation electric field region 42 formed by the ground electrode 411 and the signal electrode 412. This type of phase modulation module 100 may be used in an electro-optic modulator and directly coupled to an input spot-size conversion element and an output spot-size conversion element.

[0047] As shown in FIG. 4, in some embodiments of the present disclosure, the plurality of electrodes 41 are arranged in a first ground electrode 421, signal Electrode 422 and the second ground The second ridge layer 33 and the first ridge layer 32, including the electrode 423, form two waveguide arms 30. One of the waveguide arms 30 is the first ground Electrode 421 and signal The other waveguide arm 30 is configured to be modulated by a modulation field region 42 formed by the electrode 422, and the other waveguide arm 30 is configured to be modulated by a second ground Electrode 423 and signal The phase modulation module 100 is configured to be modulated by the modulation field region 42 formed by the electrode 422. This type of phase modulation module 100 can be used in a Mach-Zehnder modulator and directly coupled to an optical splitter or combiner, and the electrode layer 104 uses a GSG layout design.

[0048] As shown in FIG. 5 , in some embodiments of the present disclosure, the plurality of electrodes 41 includes a first ground electrode 431, a first signal electrode 432, a second ground electrode 433, a second signal electrode 434, and a third ground electrode 435 arranged in sequence. The second ridge layer 33 and the first ridge layer 32 form two waveguide arms 30. One of the waveguide arms 30 is configured to be modulated by a modulation field region 42 formed by the first ground electrode 431 and the first signal electrode 432, and the other waveguide arm 30 is configured to be modulated by a modulation field region 42 formed by the second ground electrode 433 and the second signal electrode 434. This type of phase modulation module 100 may be used in a Mach-Zehnder modulator and directly coupled to an optical splitter or combiner, and the electrode layer 104 may use a GSGSG layout design. The first signal electrode 432 and the second signal electrode 434 may be configured to receive differential signals.

[0049] In some embodiments of the present disclosure, the waveguide arms may adopt a folded design, and each waveguide arm includes at least one bent portion. For example, if the waveguide arm is folded once, it includes one bent portion, and if the waveguide arm is folded twice, it includes two bent portions. The folded design of the waveguide arms can significantly reduce the longitudinal dimension of the phase modulation module. In addition, to obtain better device performance, the length of the waveguide arms can be increased according to a desired design without significantly affecting the overall length of the device.

[0050] The waveguide arm may adopt a folded design, so that the two ends of the waveguide arm may be located on the same side or two opposite sides of the phase modulation module, depending on the number of times it is folded. For example, in some embodiments, as shown in FIG. 2 , the waveguide arm 30 is not folded or folded an even number of times so that the input end face 100 a and the output end face 100 b are located on two opposite sides of the phase modulation module 100, respectively, i.e., on two opposite sides of the phase modulation module 100. In some other embodiments, the waveguide arm is folded an odd number of times so that the input end face and the output end face are located on the same side of the phase modulation module, i.e., on the same side of the phase modulation module.

[0051] An embodiment of the present disclosure further provides an electro-optic modulator, including the phase modulation module 100 according to any one of the above-described embodiments. Based on the above design of the phase modulation module 100, the transmission loss of the electro-optic modulator can be reduced, and the operating performance of the electro-optic modulator can be improved.

[0052] As shown in FIG. 6 , in some embodiments, the electro-optic modulator 1000 is a Mach-Zehnder modulator, and the second ridge layer 33 and the first ridge layer 32 of the waveguide layer 103 form two waveguide arms 30. The electro-optic modulator 1000 further includes an optical splitter element 50 and an optical combiner element 60. The optical splitter element 50 has a ridge waveguide structure and includes a signal input end 51, a first split optical output end 52, and a second split optical output end 53. The optical combiner element 60 has a ridge waveguide structure and includes a first split optical input end 61, a second split optical input end 62, and a signal output end 63. The two waveguide arms 30 are coupled at one end to the first split optical output end 52 and the second split optical output end 53, respectively, and at the other end to the first split optical input end 61 and the second split optical input end 62, respectively.

[0053] The type of the optical dividing element 50 is not limited as long as it includes at least a signal input end 51, a first divided optical output end 52, and a second divided optical output end 53. For example, the optical dividing element may be an optical dividing element having one input and two outputs. The type of the optical combining element 60 is not limited as long as it includes at least a first divided optical input end 61, a second divided optical input end 62, and a signal output end 63. For example, the optical combining element may be an optical combining element having two inputs and one output, or an optical combining element having two inputs and three outputs.

[0054] 7, in some embodiments, the electro-optic modulator 1000 is used in a laser. The electro-optic modulator 1000 further includes a first spot-size conversion element 70 and a second spot-size conversion element 80. The first spot-size conversion element 70 has a ridge waveguide structure and includes a diverging input end 71 and a converging output end 72, and the second spot-size conversion element 80 has a ridge waveguide structure and includes a converging input end 81 and a diverging output end 82. The waveguide arm 30 has one end coupled to the converging output end 72 of the first spot-size conversion element 70 and the other end coupled to the converging input end 81 of the second spot-size conversion element 80.

[0055] The waveguide arm 30 of the phase modulation module 100 can be directly coupled to a ridge waveguide structure such as an optical splitter, an optical combiner, or a spot size converter without the need to place an optical conversion element between them, which is beneficial in reducing the transmission loss of the electro-optical modulator and improving the operating performance of the electro-optical modulator.

[0056] In the present description, the orientations, positional relationships, or dimensions indicated by terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are orientations, positional relationships, or dimensions shown based on the accompanying drawings, and it should be understood that these terms are used merely for ease of description, rather than indicating or implying that the referenced devices or elements must have a particular orientation and be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present disclosure.

[0057] Additionally, terms such as "first," "second," and "third" are for descriptive purposes only and should not be construed as indicating or implying relative importance or the number of technical features indicated. Thus, features defined as "first," "second," and "third" may explicitly or implicitly include one or more features. In describing this disclosure, the term "plurality" means two or more unless expressly and specifically defined otherwise.

[0058] In this disclosure, unless otherwise expressly or defined, terms such as "attach," "connect," "connected," and "secure" should be interpreted broadly and may refer to, for example, a fixed, detachable, or integral connection, a mechanical connection, an electrical connection, or communication, a direct connection or an indirect connection through an intermediate medium, or an internal communication or interaction between two elements. Those skilled in the art will understand the specific meaning of the above terms in this disclosure depending on the specific circumstances.

[0059] In this disclosure, unless otherwise specified or defined, a reference to a first feature being "above" or "below" a second feature may include a case where the first feature is in direct contact with the second feature, or a case where the first and second features are not in direct contact but are in contact through another feature between them. Furthermore, a reference to a first feature being "above," "above," or "on" a second feature includes a case where the first feature is directly or diagonally above the second feature, or simply indicates that the first feature is at a higher level than the second feature. A reference to a first feature being "below," "below," or "below" a second feature includes a case where the first feature is directly or diagonally below the second feature, or simply indicates that the first feature is at a lower level than the second feature.

[0060] This description provides many different implementations or examples that can be used to implement the present disclosure. It should be understood that these different implementations or examples are purely illustrative and are not intended to limit the scope of protection of the present disclosure in any way. Based on the disclosure of the description of the present disclosure, those skilled in the art may think of various modifications or substitutions. All these modifications or substitutions shall fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be subject to the scope of protection of the claims.

Claims

1. A phase modulation module having an input end face and an output end face, the phase modulation module comprising a substrate, an insulating layer, a waveguide layer, and an electrode layer arranged in that order, the electrode layer includes a plurality of spaced apart electrodes configured to form a modulated electric field region; the waveguide layer includes a plate layer, a first ridge layer, and a second ridge layer arranged in this order in a direction away from the substrate; the plate layer extends to the input end face and the output end face; the first ridge layer protrudes in a ridge shape from the surface of the plate layer and extends to the input end face and the output end face, the first ridge layer being partially located in the modulation electric field region; the second ridge layer protrudes in a ridge shape from a surface of the first ridge layer and is spaced apart from each of the input end face and the output end face, the second ridge layer being partially located in the modulation electric field region; the second ridge layer and the first ridge layer form at least one waveguide arm that extends to the input end face and the output end face and is modulated by the modulation field region; the plurality of electrodes includes a first ground electrode, a signal electrode, and a second ground electrode arranged in sequence; the second ridge layer and the first ridge layer form two waveguide arms, one of which is modulated by a modulation electric field region formed by the first ground electrode and the signal electrode, and the other waveguide arm is modulated by a modulation electric field region formed by the second ground electrode and the signal electrode; Phase modulation module.

2. the second ridge layer includes a first variable width portion, a first constant width portion, and a second variable width portion connected in sequence in the length direction; the first constant width portion has a constant width everywhere, a part of the first constant width portion is located in the modulation electric field region, and a width direction of the first constant width portion is perpendicular to the length direction; 2. The phase modulation module of claim 1, wherein the width of the first variable width portion and the width of the second variable width portion each decrease in a gradient or gradual manner in a direction away from the first constant width portion.

3. the first ridge layer includes a second constant width portion, a third variable width portion, a plate portion, a fourth variable width portion, and a third constant width portion connected in sequence in the longitudinal direction; the second constant width portion has a constant width everywhere, the third constant width portion has a constant width everywhere, a portion of the plate portion is located in the modulation field region; 3. The phase modulation module of claim 2, wherein the width of the third variable width portion and the width of the fourth variable width portion each slope or gradually decrease in a direction away from the plate portion.

4. 2. The phase modulation module of claim 1, wherein the plurality of electrodes includes a ground electrode and a signal electrode, and the second ridge layer and the first ridge layer form a single waveguide arm that is modulated by a modulation electric field region formed by the ground electrode and the signal electrode.

5. At least a portion of the electrode layer is formed on a surface of the first ridge layer away from the substrate and does not overlap the second ridge layer; or At least a portion of the electrode layer is formed on a surface of the plate layer away from the substrate and does not overlap the first ridge layer and the second ridge layer; or At least a portion of the electrode layer is formed on a surface of the insulating layer remote from the substrate and does not overlap the waveguide layer; or The phase modulation module of claim 1, further comprising an insulating support layer located between the waveguide layer and the electrode layer, and at least a portion of the electrode layer is formed on a surface of the insulating support layer away from the substrate and does not overlap the second ridge layer.

6. The phase modulation module according to claim 1 , wherein each waveguide arm includes at least one bent portion.

7. the input end face and the output end face are located on two opposite sides of the phase modulation module, respectively; or The phase modulation module according to claim 1 , wherein the input end face and the output end face are located on the same side of the phase modulation module.

8. 6. An electro-optical modulator comprising a phase modulation module according to any one of claims 1 to 5.

9. the optical fiber further includes a first spot size conversion element and a second spot size conversion element, the first spot size conversion element having a ridge waveguide structure and including a diverging input end and a converging output end, and the second spot size conversion element having a ridge waveguide structure and including a converging input end and a diverging output end; 9. The electro-optic modulator of claim 8, wherein one of the at least one waveguide arms has one end coupled to the convergent output end of the first spot size conversion element and another end coupled to the convergent input end of the second spot size conversion element.

10. the second ridge layer and the first ridge layer form at least two waveguide arms; the electro-optical modulator further comprises an optical dividing element and an optical combining element, the optical dividing element having a ridge waveguide structure and including a signal input end, a first divided optical output end, and a second divided optical output end, the optical combining element having a ridge waveguide structure and including a first divided optical input end, a second divided optical input end, and a signal output end; 9. The electro-optic modulator of claim 8, wherein two of the at least two waveguide arms are coupled at one end to the first split optical output end and the second split optical output end, respectively, and at the other end to the first split optical input end and the second split optical input end, respectively.

Images