CN116243507A

CN116243507A - Modulator

Info

Publication number: CN116243507A
Application number: CN202310003060.8A
Authority: CN
Inventors: 刘阳; 肖希; 王磊; 陈代高; 胡晓
Original assignee: Wuhan Optical Valley Information Optoelectronic Innovation Center Co Ltd
Current assignee: Wuhan Optical Valley Information Optoelectronic Innovation Center Co Ltd
Priority date: 2023-01-03
Filing date: 2023-01-03
Publication date: 2023-06-09

Abstract

The embodiment of the disclosure discloses a modulator. The modulator includes: a first optical waveguide extending in a first direction for transmitting a first optical signal; a first electrode located over the first optical waveguide and on a first side of the first optical waveguide, comprising: n first sub-electrodes; wherein, two adjacent first sub-electrodes are arranged at intervals, N is a positive integer greater than or equal to 2; a second electrode located over the first optical waveguide and on a second side of the first optical waveguide, comprising: n second sub-electrodes; wherein, two adjacent sub-electrodes are arranged at intervals; the second side is disposed opposite the first side.

Description

Modulator

Technical Field

Embodiments of the present disclosure relate to the field of integrated optics, but are not limited to, and more particularly to a modulator.

Background

The optical communication technology is a communication mode in which light is used as a carrier, and the light is used as a carrier of signals, and has the remarkable advantages of high transmission speed, high carrier frequency, small channel crosstalk, multipath parallelism, multi-dimensional information multiplexing and the like. Over the years, optical communication networks, which consist of fiber optic cables throughout the world, have become the basis for information transmission in the information age global network.

In an optical communication network, an electro-optical modulator is a key component for implementing electro-optical signal conversion, and its performance determines the transmission rate of the optical communication network. Lithium niobate is a common material for high-speed electro-optic modulators due to its strong linear electro-optic effect. In recent years, along with the maturation of thin film technology, based on thin film lithium niobate materials, an electro-optical modulator with smaller size, higher electro-optical bandwidth and higher modulation efficiency can be realized, the modulator generally adopts a traveling wave modulation structure, electrodes are coplanar waveguide transmission lines, waveguides and electrodes are parallel to each other, microwave signals and optical signals propagate along the same direction, and in the propagation process, the optical waves are continuously modulated by the microwave signals.

Disclosure of Invention

According to a first aspect of embodiments of the present disclosure, there is provided a modulator comprising:

a first optical waveguide extending in a first direction for transmitting a first optical signal;

a first electrode located over the first optical waveguide and on a first side of the first optical waveguide, comprising: n first sub-electrodes; wherein, two adjacent first sub-electrodes are arranged at intervals, N is a positive integer greater than or equal to 2;

a second electrode located over the first optical waveguide and on a second side of the first optical waveguide, comprising: n second sub-electrodes; wherein, two adjacent second sub-electrodes are arranged at intervals; the second side is disposed opposite the first side.

In some embodiments, the modulator further comprises:

the second optical waveguide is arranged in parallel with the first optical waveguide along a second direction and extends along the first direction for transmitting a second optical signal; wherein the second direction intersects the first direction; the second electrode is positioned above the first optical waveguide and the second optical waveguide and is positioned between the first optical waveguide and the second optical waveguide;

a third electrode located above the first and second optical waveguides and on a side of the second optical waveguide relatively away from the second electrode, comprising: n third sub-electrodes; wherein, the interval sets up between two adjacent third sub-electrodes.

In some embodiments, at least two of the first sub-electrodes have the same or different lengths in the first direction;

the lengths of at least two second sub-electrodes in the first direction are the same or different;

at least two of the third sub-electrodes have the same or different lengths in the first direction.

In some embodiments, the length of the ith first sub-electrode, the ith second sub-electrode, and the ith third sub-electrode in the first direction are the same; wherein i is a positive integer greater than or equal to 1 and less than or equal to N.

In some embodiments, the first optical waveguide comprises: n first waveguide portions; the second optical waveguide includes: n second waveguide portions; wherein, the liquid crystal display device comprises a liquid crystal display device,

the ith first sub-electrode and the ith second sub-electrode are used for modulating the first optical signal transmitted in the ith first waveguide part;

the ith second sub-electrode and the ith third sub-electrode are used for modulating the second optical signal transmitted in the ith second waveguide part, and i is a positive integer greater than or equal to 1 and less than or equal to N.

In some embodiments, the N first sub-electrodes are connected in parallel to the first driving circuit;

n second sub-electrodes are connected to the second driving circuit in parallel;

the N third sub-electrodes are connected to the third driving circuit in parallel.

In some embodiments, the modulator further comprises: a beam splitter for splitting an input optical signal into the first optical signal and the second optical signal; the first output end of the beam splitter is connected with the input end of the first optical waveguide, and the second output end of the beam splitter is connected with the input end of the second optical waveguide;

a beam combiner for combining the modulated first optical signal and the second optical signal into an output optical signal; the first input end of the beam combiner is connected with the output end of the first optical waveguide, and the second input end of the beam combiner is connected with the output end of the second optical waveguide.

In some embodiments, the first, second, and third sub-electrodes have lengths in the first direction that are greater than or equal to 200 microns.

In some embodiments, the first optical waveguide comprises: a straight waveguide or a curved waveguide.

In some embodiments, the first electrode and the second electrode comprise: coplanar waveguide electrodes or T-loaded coplanar waveguide electrodes.

In the embodiment of the disclosure, the first electrode and the second electrode are respectively arranged at two sides of the first optical waveguide, the first electrode is divided into N first sub-electrodes arranged at intervals, the second electrode is divided into N second sub-electrodes arranged at intervals, so that the segmented electrodes can be arranged at two sides of the first optical waveguide, each segment of electrode modulates an input optical signal in sequence in a manner of arranging the segmented electrodes, and the modulation depth (also called modulation efficiency) of pi phase shift of the optical wave can be decomposed into N segments of electrodes, which is beneficial to reducing the driving voltage of the modulator, thereby reducing the power consumption.

And the half-wave voltage is reduced by arranging the segmented electrodes, so that the lengths of the first electrode and the second electrode are not required to be additionally increased, and the high bandwidth of the modulator is ensured. That is, a modulator of high bandwidth and low half-wave voltage can be realized simultaneously by the segmented electrodes.

In addition, the segmented electrode provided by the embodiment of the disclosure is simple in design, and is beneficial to reducing the design complexity and manufacturing difficulty of the modulator.

Drawings

FIG. 1 is a top view of a modulator shown in accordance with an embodiment of the present disclosure;

FIG. 2 is a top view second of one modulator shown in accordance with an embodiment of the present disclosure;

fig. 3 is a block diagram three of a curved waveguide of a modulator according to an embodiment of the disclosure.

Detailed Description

The technical scheme of the present disclosure will be further elaborated with reference to the drawings and examples. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The present disclosure is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present disclosure will become more fully apparent from the following description and appended claims. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the disclosure.

In the presently disclosed embodiments, the terms "first," "second," and the like are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.

The technical solutions described in the embodiments of the present disclosure may be arbitrarily combined without any conflict.

The thin film lithium niobate modulator adopting the traveling wave electrode structure has the problem of compromise between two key indexes of half-wave voltage and electro-optic bandwidth. Specifically: in the case of the electrode structure parameter determination, the overlap integral of the electric field and the optical field is determined, and at this time the modulation efficiency (efficiency) is determined, the half-wave voltage vpi=efficiency/L; where L represents the electrode length. Thus, the larger the electrode length L, the smaller the half-wave voltage V pi. However, too large an electrode length L results in a reduced electro-optic bandwidth, in a rowIn the wave modulation process, due to the difference of propagation speeds between the light and the microwave signal, the modulation voltage of the light at different positions is changed, and the phase mismatch between the light and the microwave signal can be expressed as that with the increase of the propagation distance

Wherein ω, Δn, c are respectively the angular frequency of the microwave, the refractive index difference between the microwave and the light wave, the speed of light, when +.>

When the light is accumulated to 2pi, the phase change of the light caused by the microwaves becomes zero, namely, the modulation effect disappears. Thus, at a constant refractive index difference Δn between microwaves and light waves, the greater the electrode length L, the lower the electro-optic bandwidth.

In the modulation process, in order to realize high bandwidth and low half-wave voltage at the same time, a common method is mainly adopted to reduce refractive index mismatch between microwaves and light waves, and in the existing scheme process, the microwave design is relatively complex.

In view of the foregoing, embodiments of the present disclosure provide a modulator.

Fig. 1 is a top view of a modulator 100 shown in accordance with an embodiment of the disclosure.

Referring to fig. 1, a modulator 100 includes:

a first optical waveguide 111 extending in a first direction for transmitting a first optical signal;

a first electrode 121 disposed on the first optical waveguide 111 and on a first side of the first optical waveguide 111, comprising: n first sub-electrodes; wherein, two adjacent first sub-electrodes are arranged at intervals, N is a positive integer greater than or equal to 2;

a second electrode 122 located above the first optical waveguide 111 and located on a second side of the first optical waveguide 111, comprising: n second sub-electrodes; wherein, two adjacent second sub-electrodes are arranged at intervals; the second side is disposed opposite the first side.

Illustratively, referring to fig. 1, a first optical waveguide 111 extends in the x-direction, one end of the first optical waveguide 111 is for receiving an input optical signal, and the input optical signal is transmitted in the extending direction of the first optical waveguide 111 and is output from the other end of the first optical waveguide 111. Here, the first optical signal may be a part of the input optical signal, and the first direction may be expressed as an x-direction.

Fig. 1 shows a top view of the modulator 100 in the xy plane, as shown in fig. 1, the first electrode 121, the first optical waveguide 111, and the second electrode 122 are arranged side by side in the y direction, with the first optical waveguide 111 being located between the first electrode 121 and the second electrode 122. The first electrode 121 includes a plurality of first sub-electrodes arranged in parallel along the x direction, and two adjacent first sub-electrodes may be separated by an insulating layer; the second electrode 122 includes a plurality of second sub-electrodes arranged in parallel along the x direction, and two adjacent second sub-electrodes may be separated by an insulating layer. The number of the first sub-electrode and the second sub-electrode may be two or more, and the embodiments of the present disclosure are not particularly limited.

Here, the first electrode 121 and the second electrode 122 are respectively located at both sides of the first optical waveguide 111, and the first electrode 121 is divided into N first sub-electrodes disposed at intervals, and the second electrode 122 is divided into N second sub-electrodes disposed at intervals. After the first optical waveguide 111 receives the input optical signal, the input optical signal is transmitted along the extending direction of the first optical waveguide 111, and the 1 st first sub-electrode and the 1 st second sub-electrode, the 2 nd first sub-electrode and the 2 nd second sub-electrode, … …, the nth first sub-electrode and the nth second sub-electrode can respectively modulate the input optical signal at different positions in the first optical waveguide 111.

It should be noted that fig. 1 only shows a top view of the modulator in the xy plane, and the first electrode 121 and the second electrode 122 are both located above the first optical waveguide 111 in a direction perpendicular to the xy plane, and are located on two sides (i.e., a first side and a second side) of the first optical waveguide 111 that are disposed opposite to each other in the y direction. It is understood that the first electrode 121 and the first optical waveguide 111 are located in different levels of the modulator, the second electrode 122 and the first optical waveguide 111 are located in different levels of the modulator, and the first electrode 121 and the second electrode 122 may be located in the same or different levels, which is not limited herein.

In some embodiments, the first electrode 121 and the first optical waveguide 111 have a first pitch in the y-direction, and the second electrode 122 and the first optical waveguide 111 have a second pitch in the y-direction, which may be the same or different, and the disclosure is not limited herein.

In some embodiments, the lengths of the first electrode 121 and the second electrode 122 in the x-direction are the same. In other embodiments, the lengths of the first electrode 121 and the second electrode 122 in the x-direction are different. The length L of each of the first electrode 121 and the second electrode 122 in the x direction will be described below as an example.

In some embodiments, N first sub-electrodes are connected in parallel by a first lead, and N second sub-electrodes are connected in parallel by a second lead. When an electric signal is applied to the first electrode and the second electrode, the half-wave voltage V pi = effeciency/L/N of each section of electrode, and because the N sections of sub-electrodes are connected in parallel, the driving voltage of the modulator is also effeciency/L/N, so that the half-wave voltage can be reduced, namely, the low half-wave voltage is realized.

In some embodiments, the material of the first optical waveguide 111 includes: silicon, silicon nitride or lithium niobate.

In some embodiments, the materials of the first electrode 121 and the second electrode 122 include: gold, copper, platinum, or other metals or metal alloys of at least two metals.

In the embodiment of the disclosure, the first electrode and the second electrode are respectively arranged at two sides of the first optical waveguide, the first electrode is divided into N first sub-electrodes arranged at intervals, the second electrode is divided into N second sub-electrodes arranged at intervals, so that the segmented electrodes can be arranged at two sides of the first optical waveguide, each segment of electrode modulates the first optical signal in sequence in a manner of arranging the segmented electrodes, and the modulation depth (also called modulation efficiency) of pi phase shift of the optical wave can be decomposed into N segments of electrodes, which is beneficial to reducing the driving voltage of the modulator, thereby reducing the power consumption.

In some embodiments, referring to fig. 1, the modulator 100 further comprises: a second optical waveguide 112 disposed in parallel with the first optical waveguide 111 along a second direction and extending along the first direction for transmitting a second optical signal; wherein the second direction intersects the first direction; the second electrode 122 is located above the first optical waveguide 111 and the second optical waveguide 112, and is located between the first optical waveguide 111 and the second optical waveguide 112;

a third electrode 123 disposed above the first optical waveguide 111 and the second optical waveguide 112 and on a side of the second optical waveguide 112 relatively far from the second electrode 122, comprising: n third sub-electrodes; wherein, the interval sets up between two adjacent third sub-electrodes.

Illustratively, referring to fig. 1, a second optical waveguide 112 is disposed in parallel with the first optical waveguide 111 in the y-direction, the second optical waveguide 112 extends in the x-direction, one end of the second optical waveguide 112 is for receiving an input optical signal, and the input optical signal is transmitted in the extending direction of the second optical waveguide 112 and is output from the other end of the second optical waveguide 112. Here, the second optical signal may be another part of the input optical signal, and the second direction may be expressed as a y-direction.

In some embodiments, the modulator comprises a Mach-Zehnder interferometer (Mach-Zehnder interferometer, MZI) type modulator, the first optical waveguide and the second optical waveguide respectively act as two interference arms of the MZI type modulator, and the first electrode, the second electrode, and the third electrode form traveling wave electrodes of the MZI type modulator. The modulator may also be other types of modulators known in the art.

It should be noted that, as used in the present disclosure, the first direction and the second direction are denoted as an x direction and a y direction, respectively, and the first direction and the second direction are both parallel to a plane on which a substrate (not shown in the drawing) is located, and an included angle between the first direction and the second direction includes an acute angle, a right angle, or an obtuse angle, which is not particularly limited in the present disclosure. In a specific example, the angle between the first direction and the second direction comprises a right angle, i.e. the first direction and the second direction are perpendicular. Here, the substrate is used to carry the first optical waveguide and the second optical waveguide, i.e. the first optical waveguide and the second optical waveguide are formed over the substrate.

As shown in the top view of fig. 1, the second electrode 122, the second optical waveguide 112, and the third electrode 123 are juxtaposed in the y-direction, and the second optical waveguide 112 is located between the second electrode 122 and the third electrode 123. The third electrode 123 includes a plurality of third sub-electrodes arranged in parallel along the x direction, and two adjacent third sub-electrodes may be spaced apart from each other by an insulating layer. The number of the third sub-electrodes may be two or more, and the embodiment of the present disclosure is not particularly limited.

Here, the second electrode 122 and the third electrode 123 are respectively located at both sides of the second optical waveguide 112, and the second electrode 122 is divided into N second sub-electrodes disposed at intervals, and the third electrode 123 is divided into N third sub-electrodes disposed at intervals. After the second optical waveguide 112 receives the input optical signal, the input optical signal is transmitted along the extending direction of the second optical waveguide 112, and the 1 st second sub-electrode and the 1 st third sub-electrode, the 2 nd second sub-electrode and the 2 nd third sub-electrode, … …, the nth second sub-electrode and the nth third sub-electrode can respectively modulate the input optical signal at different positions in the second optical waveguide 112.

In fig. 1, only a top view of the modulator in the xy plane is shown, and in a direction perpendicular to the xy plane, the third electrode 123 is located above the second optical waveguide 112, and the second electrode 122 and the third electrode 123 are located on opposite sides of the second optical waveguide 112 in the y direction. It is understood that second electrode 122 and second optical waveguide 112 are located in different levels of the modulator, third electrode 123 and second optical waveguide 112 are located in different levels of the modulator, second electrode 122 and third electrode 123 may be located in the same or different levels, and the disclosure is not limited herein.

In some embodiments, second electrode 122 and second optical waveguide 112 have a third pitch in the y-direction, third electrode 123 and second optical waveguide 112 have a fourth pitch in the y-direction, which may be the same or different, and the disclosure is not limited herein.

In some embodiments, any two of the first pitch, the second pitch, the third pitch, and the fourth pitch may be the same or different. For example, the first pitch and the second pitch are the same, the third pitch and the fourth pitch are the same, and the first pitch and the third pitch are different. For another example, the first pitch and the second pitch are the same, the third pitch and the fourth pitch are the same, and the first pitch and the third pitch are the same.

In some embodiments, the second electrode 122 and the third electrode 123 are the same length in the x-direction. In other embodiments, the second electrode 122 and the third electrode 123 are different in length in the x-direction. The lengths of the first electrode 121, the second electrode 122, and the third electrode 123 in the x direction are all L, which will be described below as an example.

In some embodiments, N second sub-electrodes are connected in parallel by a second lead, and N third sub-electrodes are connected in parallel by a third lead. When an electric signal is applied to the second electrode and the third electrode, the half-wave voltage V pi = effeciency/L/N of each section of electrode, and the driving voltage of the modulator is also effeciency/L/N because the N sections of sub-electrodes are connected in parallel, so that the half-wave voltage can be reduced, namely, the low half-wave voltage is realized.

In some embodiments, the material of the second optical waveguide 111 includes: silicon, silicon nitride or lithium niobate.

In some embodiments, the material of the third electrode 123 includes: gold, copper, platinum, or other metals or metal alloys of at least two metals.

In the embodiment of the disclosure, the second optical waveguide is arranged in parallel with the first optical waveguide, and the third electrode is arranged on one side, relatively far away from the second electrode, of the second optical waveguide, and the third electrode comprises N third sub-electrodes arranged at intervals, so that segmented electrodes can be arranged on two sides of the second optical waveguide, and each segment of electrode sequentially modulates the second optical signal in a manner of arranging the segmented electrodes, so that the modulation depth (also called modulation efficiency) of pi phase shift of the optical wave can be decomposed into N segments of electrodes, which is beneficial to reducing the driving voltage of the modulator, and further reducing the power consumption.

In some embodiments, the lengths of the at least two first sub-electrodes in the first direction are the same or different.

In an example, referring to fig. 1, the 1 st first sub-electrode, the 2 nd first sub-electrode, … …, and the nth first sub-electrode are all the same in length in the x direction. Here, the first electrode 121 may be divided into N first sub-electrodes arranged side by side in the x direction in an equally divided manner such that the length of each first sub-electrode in the x direction is the same.

In another example, referring to fig. 1, at least two first sub-electrodes of the 1 st first sub-electrode, the 2 nd first sub-electrode, the … … nd first sub-electrode, and the nth first sub-electrode have the same length in the x direction, and the other first sub-electrodes of the 1 st first sub-electrode, the 2 nd first sub-electrode, the … … nd first sub-electrode, and the nth first sub-electrode may have the same or different lengths in the x direction.

In yet another example, referring to fig. 1, the 1 st first sub-electrode, the 2 nd first sub-electrode, … …, and the nth first sub-electrode are all different in length in the x-direction. Here, the first electrode 121 may be divided into N first sub-electrodes arranged side by side in the x direction in a non-divided manner such that the lengths of each first sub-electrode in the x direction are different. It should be noted that, the 1 st first sub-electrode, the 2 nd first sub-electrode, the … … nd first sub-electrode, and the nth first sub-electrode all represent first sub-electrodes, so that the difference in the positions of the N first sub-electrodes is conveniently distinguished, and the description of a specific order or sequence is not necessary.

In the embodiment of the disclosure, by setting the lengths of at least two first sub-electrodes in the first direction to be the same, the optical signals transmitted in the first optical waveguide are uniformly modulated, the modulation efficiency is improved, and the complexity of the design of the modulator device is reduced.

In some embodiments, the lengths of the at least two second sub-electrodes in the first direction are the same or different.

In an example, referring to fig. 1, the 1 st second sub-electrode, the 2 nd second sub-electrode, … …, and the nth second sub-electrode are all the same in length in the x direction. Here, the second electrode 122 may be divided into N second sub-electrodes arranged side by side in the x-direction in an equally divided manner such that the length of each second sub-electrode in the x-direction is the same.

In another example, referring to fig. 1, at least two of the 1 st second sub-electrode, the 2 nd second sub-electrode, the … … nd second sub-electrode have the same length in the x-direction, and the other of the 1 st second sub-electrode, the 2 nd second sub-electrode, the … … nd second sub-electrode, the nth second sub-electrode may have the same length or different lengths in the x-direction.

In yet another example, referring to fig. 1, the 1 st second sub-electrode, the 2 nd second sub-electrode, … …, and the nth second sub-electrode are all different in length in the x-direction. Here, the second electrode 122 may be divided into N second sub-electrodes arranged side by side in the x direction in a non-uniform manner such that the lengths of each of the second sub-electrodes in the x direction are different. It should be noted that, the 1 st second sub-electrode, the 2 nd second sub-electrode, the … … nd second sub-electrode, and the nth second sub-electrode all represent second sub-electrodes, so that the difference in the positions of the N second sub-electrodes is conveniently distinguished, and the description of a specific order or sequence is not necessary.

In the embodiment of the disclosure, by setting the lengths of at least two second sub-electrodes in the first direction to be the same, the optical signals transmitted in the first optical waveguide and the second optical waveguide are uniformly modulated, the modulation efficiency is improved, and the complexity of the design of the modulator device is reduced.

In some embodiments, the lengths of the at least two third sub-electrodes in the first direction are the same or different.

In an example, referring to fig. 1, the 1 st third sub-electrode, the 2 nd third sub-electrode, the … … th third sub-electrode, and the nth third sub-electrode are all the same in length in the x direction. Here, the third electrode 123 may be divided into N third sub-electrodes arranged side by side in the x-direction in an equally divided manner such that the length of each third sub-electrode in the x-direction is the same.

In another example, referring to fig. 1, at least two of the 1 st, 2 nd, … … and nth third sub-electrodes have the same length in the x-direction, and the other of the 1 st, 2 nd, … … and nth third sub-electrodes may have the same or different lengths in the x-direction.

In an example, referring to fig. 1, the 1 st third sub-electrode, the 2 nd third sub-electrode, the … … th third sub-electrode, and the nth third sub-electrode are all different in length in the x direction. Here, the third electrode 123 may be divided into N third sub-electrodes arranged side by side in the x direction in a non-uniform manner such that the length of each third sub-electrode in the x direction is different. It should be noted that, the 1 st third sub-electrode, the 2 nd third sub-electrode, the … … nd third sub-electrode, and the nth third sub-electrode all represent third sub-electrodes, so that the difference in positions of the N third sub-electrodes is convenient to distinguish, and is not necessary to describe a specific order or sequence.

In the embodiment of the disclosure, by setting the lengths of at least two third sub-electrodes in the first direction to be the same, the optical signals transmitted in the second optical waveguide are uniformly modulated, the modulation efficiency is improved, and the complexity of the design of the modulator device is reduced.

In practical applications, those skilled in the art may select according to practical requirements, and the manner of dividing the first electrode into N first sub-electrodes, dividing the second electrode into N second sub-electrodes, and dividing the third electrode into N third sub-electrodes in the embodiments of the present disclosure is not particularly limited.

In some embodiments, the length of the ith first sub-electrode, the ith second sub-electrode, and the ith third sub-electrode in the first direction are the same; wherein i is a positive integer greater than or equal to 1 and less than or equal to N. For example, the 1 st first sub-electrode, the 1 st second sub-electrode, and the 1 st third sub-electrode have the same length in the x-direction, i.e., the first sub-electrode and the second sub-electrode on both sides of the first optical waveguide 111 have the same length, and the second sub-electrode and the third sub-electrode on both sides of the second optical waveguide 112 have the same length.

It is understood that the traveling wave electrode formed by the first electrode, the second electrode and the third electrode includes a plurality of traveling wave sub-electrodes arranged in parallel along the x direction, the traveling wave sub-electrodes include an ith first sub-electrode, an ith second sub-electrode and an ith third sub-electrode arranged in parallel along the y direction, and the traveling wave sub-electrodes are used for modulating the first optical signal transmitted in at least part of the first optical waveguide and the second optical signal transmitted in at least part of the second optical waveguide.

In the embodiment of the disclosure, the lengths of the first sub-electrode and the second sub-electrode which are positioned at the two sides of the first optical waveguide are the same, and the lengths of the second sub-electrode and the third sub-electrode which are positioned at the two sides of the second optical waveguide are the same, so that uniform modulation of optical signals transmitted in the first optical waveguide and the second optical waveguide is facilitated, the modulation efficiency is improved, and the complexity of the design of a modulator device is reduced.

In some embodiments, the first optical waveguide 111 includes: n first waveguide portions; the second optical waveguide 112 includes: n second waveguide portions; wherein the ith first sub-electrode and the ith second sub-electrode are for modulating the first optical signal transmitted in the ith first waveguide section; the ith second sub-electrode and the ith third sub-electrode are used for modulating the second optical signal transmitted in the ith second waveguide part, and i is a positive integer greater than or equal to 1 and less than or equal to N.

As shown in fig. 1, the input optical signal is split into a first optical signal and a second optical signal, and the first optical signal sequentially passes through the 1 st first waveguide portion, the 2 nd first waveguide portion, the … … nd first waveguide portion, and the nth first waveguide portion in the process of being transmitted along the extending direction of the first optical waveguide 111. For example, when the first optical signal is transmitted through the 1 st first waveguide section, the 1 st first sub-electrode and the 1 st second sub-electrode on both sides of the 1 st first waveguide section are used to modulate the first optical signal transmitted in the 1 st first waveguide section; for another example, the 2 nd first sub-electrode and the 2 nd second sub-electrode on both sides of the 2 nd first waveguide part are used to modulate the first optical signal transmitted in the 2 nd first waveguide part when the first optical signal is transmitted through the 2 nd first waveguide part; similarly, … …, when the first optical signal is transmitted through the nth first waveguide portion, the nth first sub-electrode and the nth second sub-electrode on both sides of the nth first waveguide portion are used for modulating the first optical signal transmitted in the nth first waveguide portion until output.

The second optical signal sequentially passes through the 1 st second waveguide section, the 2 nd second waveguide section, … …, and the nth second waveguide section in the course of being transmitted in the extending direction of the second optical waveguide 112. For example, when the second optical signal is transmitted through the 1 st second waveguide section, the 1 st second sub-electrode and the 1 st third sub-electrode on both sides of the 1 st second waveguide section are used to modulate the second optical signal transmitted in the 1 st second waveguide section; for another example, the 2 nd second sub-electrode and the 2 nd third sub-electrode on both sides of the 2 nd second waveguide part are used to modulate the second optical signal transmitted in the 2 nd second waveguide part when the second optical signal is transmitted through the 2 nd second waveguide part; similarly, … …, when the second optical signal is transmitted through the nth second waveguide portion, the nth second sub-electrode and the nth third sub-electrode on both sides of the nth second waveguide portion are used for modulating the second optical signal transmitted in the nth second waveguide portion until output.

It will be appreciated that the first optical signal is transmitted along the first optical waveguide 111, and sequentially passes through the 1 st first waveguide section, the 2 nd first waveguide section, … …, and the nth first waveguide section, and the first optical signal transmitted in each first waveguide section is modulated by the first sub-electrode and the second sub-electrode located on both sides thereof; the second optical signal is transmitted along the second optical waveguide 112, sequentially passing through the 1 st second waveguide section, the 2 nd second waveguide section, … …, and the nth second waveguide section, and the second optical signal transmitted in each second waveguide section is modulated by the second sub-electrode and the third sub-electrode located at both sides thereof.

In practical application, different voltages can be applied to the first sub-electrode and the second sub-electrode which are positioned at two sides of the first waveguide part, and the electric field formed between the first sub-electrode and the second sub-electrode can modulate the first optical signal transmitted in the first waveguide part; different voltages may be applied to the second sub-electrode and the third sub-electrode located at both sides of the second waveguide part, and an electric field formed between the second sub-electrode and the third sub-electrode may modulate a second optical signal transmitted in the second waveguide part.

In some embodiments, the N first sub-electrodes are connected in parallel to the first driving circuit; n second sub-electrodes are connected to the second driving circuit in parallel; the N third sub-electrodes are connected to the third driving circuit in parallel.

Fig. 2 shows schematically a connection of the second electrode. Referring to fig. 2, N first sub-electrodes are connected in parallel to a first driving circuit (not shown), N second sub-electrodes are connected in parallel to a second driving circuit, and a modulation signal for modulating a first optical signal transmitted in the first waveguide portion, for example, modulating a phase of the first optical signal, may be applied to the first waveguide portion between the first sub-electrodes and the second sub-electrodes through the first driving circuit and the second driving circuit. In a specific example, the phase control may be performed by a digital signal (e.g., a phase shifter may be provided) to introduce a phase difference on the first sub-electrode and the second sub-electrode on both sides of the first waveguide portion, e.g., a phase difference between adjacent two sub-electrodes

By introducing phase delay corresponding to light wave transmission in each section of modulation signal, the speed matching between light waves and microwaves is ensured, and the realization of the integral high electro-optical bandwidth of the modulator is facilitated.

Similarly, N second sub-electrodes are connected in parallel to the second driving circuit, N third sub-electrodes are connected in parallel to a third driving circuit (not shown in the figure), and a modulation signal for modulating the second optical signal transmitted in the second waveguide section, for example, modulating the phase of the second optical signal, can be applied to the second waveguide section between the second sub-electrodes and the third sub-electrodes by the second driving circuit and the third driving circuit. In a specific example, the phase control may be performed by a digital signal (e.g., a phase shifter may be provided) to introduce a phase difference on the second and third sub-electrodes on both sides of the second waveguide portion, e.g., adjacent two sub-electrodesThe phase difference is

It should be noted that the phase difference between two adjacent sub-electrodes may be the same or different, for example, the phase difference between the 1 st first sub-electrode and the 2 nd first sub-electrode is

The phase difference between the 2 nd first sub-electrode and the 3 rd first sub-electrode is +.>

And->

May be the same or different.

Here, the phase difference introduced on the first sub-electrode and the second sub-electrode on both sides of the first waveguide portion is related to the way in which the first electrode and the second electrode are segmented, and when the first electrode and the second electrode are segmented in an equal manner, the phase difference between the adjacent two sub-electrodes is the same, and when the first electrode and the second electrode are segmented in an unequal manner, the phase difference between the adjacent two sub-electrodes is different.

Similarly, the phase difference introduced on the second sub-electrode and the third sub-electrode on both sides of the second waveguide portion is related to the manner of segmentation of the second electrode and the third electrode, and when the second electrode and the third electrode are segmented in an equal manner, the phase difference between the adjacent two sub-electrodes is the same, and when the second electrode and the third electrode are segmented in an unequal manner, the phase difference between the adjacent two sub-electrodes is different.

In some embodiments, the first, second, and third drive circuits may be integrated in the same optical chip as the modulator, and in other embodiments, the first, second, and third drive circuits may be drive chips that are independent of the modulator.

In some embodiments, the first driving circuit, the second driving circuit and the third driving circuit may be complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS circuit) direct output, or may be COMS circuit and driving power supply common output.

In the embodiment of the disclosure, by arranging N first sub-electrodes connected to the first driving circuit in parallel, N second sub-electrodes connected to the second driving circuit in parallel, and N third sub-electrodes connected to the third driving circuit in parallel, a phase delay corresponding to light wave transmission can be introduced into each section of modulation signal, so that speed matching between light waves and microwaves is ensured, and the realization of the overall high electro-optical bandwidth of the modulator is facilitated.

And the modulation depth of the pi phase shift of the light wave is decomposed into N sections of electrodes by adopting a sectional electrode mode, and the half-wave voltage V pi = effeciency/L/N of each section of electrode is favorable for reducing the driving half-wave voltage of the modulator, so that the power consumption is reduced. That is, a modulator of high bandwidth and low half-wave voltage can be realized simultaneously by the segmented electrodes.

In some embodiments, referring to fig. 1, the modulator 100 further comprises:

a beam splitter 130 for splitting an input optical signal into a first optical signal and a second optical signal; wherein a first output end of the beam splitter 130 is connected to an input end of the first optical waveguide 111, and a second output end of the beam splitter 130 is connected to an input end of the second optical waveguide 112;

a combiner 140 for combining the modulated first optical signal and the second optical signal into an output optical signal; the first input end of the beam combiner 140 is connected to the output end of the first optical waveguide 111, and the second input end of the beam combiner is connected to the output end of the second optical waveguide 112.

The beam splitter 130, the beam combiner 140, the first optical waveguide 111, the second optical waveguide 112, the first electrode 121, the second electrode 122, and the third electrode 123 constitute a Mach-Zehnder int erferometer, MZI structure.

The beam splitter 130 is configured to divide an input optical signal into two optical signals (e.g., a first optical signal and a second optical signal), the two optical signals respectively enter two arms (i.e., the first optical waveguide 111 and the second optical waveguide 112) of the mach-zehnder interferometer structure, when the first electrode and the second electrode are driven by the driving circuit, the first optical signal is affected by the modulating signal when the first optical waveguide 111 is transmitted, and thus the phase of the first optical signal is modulated, when the second electrode and the third electrode are driven by the driving circuit, the second optical signal is affected by the modulating signal when the second optical waveguide 112 is transmitted, and thus the phase of the second optical signal is modulated, and the modulated first optical signal and the second optical signal enter the combiner 140 to interfere, and finally the output optical signal is the modulated optical signal.

In some embodiments, beam splitter 130 includes: a 1 x 2 beam splitter or a 2 x 2 beam splitter. Here, the 1×2 beam splitter has 1 input terminal and 2 output terminals, and the 2×2 beam splitter has 2 input terminals and 2 output terminals.

In some embodiments, beam combiner 140 includes: 2 x 1 beam combiners or 2 x 2 beam combiners. Here, the 2×1 combiner has 2 inputs and 1 output, and the 2×2 combiner has 2 inputs and 2 outputs.

It should be noted that, too small lengths of the first sub-electrode, the second sub-electrode, and the third sub-electrode may cause an increase in the resistances of the first sub-electrode, the second sub-electrode, and the third sub-electrode, which affects the transmission of the modulation signal (i.e., the electrical signal), and reduces the modulation efficiency of the input optical signal.

In some embodiments, referring to fig. 1, the first, second, and third sub-electrodes have lengths in the first direction of greater than or equal to 200 microns.

In the embodiment of the disclosure, the lengths of the first sub-electrode, the second sub-electrode and the third sub-electrode in the first direction are greater than or equal to 200 micrometers, so that the influence of the resistance values of the first sub-electrode, the second sub-electrode and the third sub-electrode on modulation signals is reduced, and the modulation efficiency is further ensured.

In some embodiments, N is a positive integer greater than or equal to 2 and less than or equal to 10. In practical application, the length of the traveling wave electrode is generally constant, and if the value of N is too large, the length of each sub-electrode is smaller, and the resistance of each sub-electrode is increased. Here, by setting N to 2 or more and 10 or less, it is advantageous to reduce the influence of the resistance value of the electrode itself on the modulation signal while setting the electrode as a segmented electrode.

In some embodiments, referring to fig. 1 or 3, the first optical waveguide 111 includes: a straight waveguide or a curved waveguide.

In some embodiments, referring to fig. 1 or 3, second optical waveguide 112 comprises: a straight waveguide or a curved waveguide.

In some embodiments, the first electrode 121 and the second electrode 122 include: coplanar waveguide electrodes or T-loaded coplanar waveguide electrodes.

In an example, the first electrode 121 and the second electrode 122 are coplanar waveguide electrodes, which can reduce the effective refractive index of the microwave signal, and satisfy the speed matching.

In another example, the first electrode 121 and the second electrode 122 are T-loading coplanar waveguide electrodes.

The foregoing is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the disclosure, and it should be covered in the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A modulator, comprising:

2. The modulator of claim 1, wherein the modulator further comprises:

3. The modulator of claim 2, wherein,

the lengths of at least two first sub-electrodes in the first direction are the same or different;

4. A modulator according to claim 2 or 3, wherein the length of the i first sub-electrode, the i second sub-electrode and the i third sub-electrode in the first direction are the same; wherein i is a positive integer greater than or equal to 1 and less than or equal to N.

5. The modulator of claim 2, wherein the first optical waveguide comprises: n first waveguide portions; the second optical waveguide includes: n second waveguide portions; wherein, the liquid crystal display device comprises a liquid crystal display device,

6. The modulator of claim 5, wherein the modulator further comprises a modulator,

the N first sub-electrodes are connected to the first driving circuit in parallel;

7. The modulator of claim 2, wherein the modulator further comprises:

a beam splitter for splitting an input optical signal into the first optical signal and the second optical signal; the first output end of the beam splitter is connected with the input end of the first optical waveguide, and the second output end of the beam splitter is connected with the input end of the second optical waveguide;

8. The modulator of claim 2, wherein the first, second, and third sub-electrodes have lengths in the first direction that are greater than or equal to 200 microns.

9. The modulator of claim 1, wherein the first optical waveguide comprises: a straight waveguide or a curved waveguide.

10. The modulator of claim 1, wherein the first electrode and the second electrode comprise: coplanar waveguide electrodes or T-loaded coplanar waveguide electrodes.