Optical mode modulator and photonic chip

Abstract

The present disclosure provides an optical mode modulator and a photonic chip, the optical mode modulator including: a mode separation element including an optical signal input end, a first output end configured to output an optical signal in TE mode, and a second output end configured to output an optical signal in TM mode, a first branch optical path connected to the first output end and a second branch optical path connected to the second output end, the first branch optical path being provided with an optical mode converter for converting the optical signal in TE mode to an optical signal in TM mode, or the second branch optical path being provided with an optical mode converter for converting the optical signal in TM mode to an optical signal in TE mode, a phase modulation module configured to modulate a phase difference between the first branch optical path and the second branch optical path based on a predetermined optical power division ratio, and a Mach-Zehnder modulator including first and second input ends configured to receive two branch optical signals, both in TE mode or TM mode, from the first branch optical path and the second branch optical path, respectively, and further including an output end for the modulated optical signal.

Description

[Technical Field]

[0001] This application references Chinese Patent Application No. 202211369871.1, filed on November 3, 2022, entitled "Optical Mode Modulation Device and Photonic Chip," the entire contents of which are incorporated herein by reference. The present disclosure relates to the field of optoelectronic technology, and in particular to optical mode modulators and photonic chips. [Background technology]

[0002] Photonic chips generally rely on dielectric optical waveguides in integrated optics or silicon-based optoelectronic circuits to transmit optical signals in guided modes by using light waves (electromagnetic waves) as carriers for information transmission or data computation, allowing the modulation, transmission, demodulation, etc. of optical and electrical signals to be integrated on the same substrate or chip.

[0003] Compared to electronic integrated circuits or electrical interconnection technologies, photonic integrated circuits and optical interconnections exhibit lower transmission losses, wider transmission bandwidths, lower time delays, and greater immunity to electromagnetic interference. In addition, optical interconnections may be used to increase communication capacity in transmission media by employing various multiplexing methods (e.g., wavelength division multiplexing (WDM), mode division multiplexing (MDM), etc.).

[0004] How to improve the operation performance of photonic chips and reduce the transmission loss of light in photonic chips is an important part of research for those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION Embodiments of the present disclosure provide an optical mode modulator and a photonic chip to improve the operational performance of the photonic chip and reduce the transmission loss of light in the photonic chip. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided an optical mode modulation device, comprising: a mode separation element including an optical signal input end, a first output end, and a second output end, the optical signal input end configured to receive an input optical signal, the first output end configured to output an optical signal in TE mode, and the second output end configured to output an optical signal in TM mode; and a first branch optical path and a second branch optical path, the first branch optical path connected to the first output end, and the second branch optical path connected to the second output end, the first branch optical path being provided with an optical mode converter for converting the optical signal in TE mode into an optical signal in TM mode, or the second branch optical path being provided with an optical mode converter for converting the optical signal in TM mode into an optical signal in TM mode. The optical fiber modulator includes a first branch optical path and a second branch optical path, each provided with an optical mode converter for converting an optical signal into a TE mode optical signal; a phase modulation module configured to modulate a phase difference between the first branch optical path and the second branch optical path based on a predetermined optical power distribution ratio; and a Mach-Zehnder modulator including a first input end, a second input end, and an output end for a modulated optical signal, the first input end being connected to the first branch optical path and the second input end being connected to the second branch optical path, and receiving two branch optical signals, both of which are in the TE mode or the TM mode, from the first branch optical path and the second branch optical path, respectively.

[0007] In some embodiments, the two branched optical signals output from the first branched optical path and the second branched optical path, respectively, are both TE mode optical signals, and the second branched optical path is provided with an optical mode converter for converting the TM mode optical signal into the TE mode optical signal.

[0008] In some embodiments, the two branched optical signals output from the first branched optical path and the second branched optical path, respectively, are both TM-mode optical signals, and the first branched optical path is provided with an optical mode converter for converting the TE-mode optical signal into the TM-mode optical signal.

[0009] In some embodiments, the phase modulation module includes a first phase modulator provided in the first branch optical path and / or a second phase modulator provided in the second branch optical path.

[0010] In some embodiments, the phase modulation module is an electro-optic phase modulation module or a thermo-optic phase modulation module.

[0011] In some embodiments, the optical mode modulator further includes an optical dividing element including an input end, a third output end, and a fourth output end of the optical dividing element, wherein the input end of the optical dividing element is connected to the output end of the modulated optical signal, the third output end is configured to output the operating signal, and the fourth output end is configured to output the monitoring signal; and a monitoring sensor configured to detect a signal strength of the monitoring signal.

[0012] In some embodiments, the optical mode modulation device further includes a feedback module separately connected to the monitoring sensor and the phase modulation module and configured to output a first feedback signal to the phase modulation module and a second feedback signal to the modulation electrode of the Mach-Zehnder modulator based on the signal strength of the monitoring signal.

[0013] According to one aspect of the present disclosure, there is provided an optical mode modulation device including: a mode separation element configured to receive an input optical signal and separate the optical signal into a first optical signal of a first mode and a second optical signal of a second mode; first and second branch optical paths configured to receive the first and second optical signals output by the mode separation element, respectively, where the first branch optical path is provided with an optical mode converter for converting the first optical signal from the first mode to the second mode; a phase modulation module configured to modulate a phase difference between the first and second branch optical paths based on a predetermined optical power division ratio; and a Mach-Zehnder modulator configured to receive the first and second optical signals, both of which are in the second mode, from the first and second branch optical paths, modulate the first and second optical signals, and output a modulated optical signal.

[0014] In some embodiments, the phase modulation module includes a first phase modulator disposed in the first optical path branch.

[0015] In some embodiments, the phase modulation module includes a second phase modulator disposed in the second optical path branch.

[0016] According to one aspect of the present disclosure, there is provided a photonic chip including an optical mode modulator according to any one of the above-described embodiments, wherein the mode separation element of the optical mode modulator is configured to be optically coupled to an optical fiber.

[0017] The optical mode modulation device according to one or more embodiments of the present disclosure is applied in a photonic chip, which enables an input optical signal to be modulated to obtain an operating signal with high modal purity, thereby improving the operating performance of the photonic chip and reducing the transmission loss of light in the photonic chip.

[0018] It should be understood that the contents described in this section are not intended to identify key or important features of the embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent from the following description.

[0019] More 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]

[0020] [Figure 1] 1 is a block diagram of the structure of an optical mode modulator according to some exemplary embodiments of the present disclosure; [Figure 2] 10A and 10B are block diagrams of the structure of optical mode modulators according to some other exemplary embodiments of the present disclosure. [Figure 3] 1 is a block diagram of the structure of an optical mode modulator according to some further exemplary embodiments of the present disclosure. [Figure 4] 1 is a block diagram of the structure of an optical mode modulator according to some further exemplary embodiments of the present disclosure. [Figure 5] FIG. 1 is a block diagram of an optical chip structure according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0021] Only a few exemplary embodiments are briefly described below. As will be understood by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. Accordingly, the accompanying drawings and descriptions are to be regarded as illustrative in nature, rather than restrictive.

[0022] Typically, the direction of electromagnetic waves propagating through optical fibers is unstable. At the optically coupled end face between the optical fiber and the photonic chip, the ratio of the horizontal and vertical electric fields of the electromagnetic waves in the optical fiber is uncontrollable. For example, the vertical electric field accounts for 10% of the electromagnetic wave, and the horizontal electric field accounts for 90% of the electromagnetic wave, but other mixing ratios are possible. The optical field mode of the horizontal electric field in the optical fiber corresponds to the TE mode in the waveguide, and the optical field mode of the vertical electric field in the optical fiber corresponds to the TM mode in the waveguide. As a result of the uncontrollable ratio of the horizontal and vertical electric fields in the optical fiber, the operating performance of the photonic chip becomes uncontrollable, which has a significant impact on the operating performance of the photonic chip and also causes a certain optical loss.

[0023] Embodiments of the present disclosure provide an optical mode modulator and a photonic chip, wherein the optical mode modulator is applied in the photonic chip, which can improve the operation performance of the photonic chip and reduce the transmission loss of light in the photonic chip.

[0024] As shown in FIG. 1, an optical mode modulation device 100 according to some embodiments of the present disclosure includes a mode separation element 110, a Mach-Zehnder modulator 120, a first branch optical path 130 and a second branch optical path 140 connected between the mode separation element 110 and the Mach-Zehnder modulator 120, and a phase modulation module 160.

[0025] The mode separation element 110 includes an optical signal input terminal 1a, a first output terminal 1b, and a second output terminal 1c. The optical signal input terminal 1a is configured to receive an input optical signal, the first output terminal 1b is configured to output a TE-mode optical signal, and the second output terminal 1c is configured to output a TM-mode optical signal. A first branch optical path 130 is coupled to the first output terminal 1b, and a second branch optical path 140 is coupled to the second output terminal 1c. The second branch optical path 140 is provided with an optical mode converter 150 for converting a TM-mode optical signal into a TE-mode optical signal (or the first branch optical path 130 is provided with an optical mode converter for converting a TE-mode optical signal into a TM-mode optical signal). The phase modulation module 160 is configured to modulate the phase difference between the first branch optical path and the second branch optical path based on a predetermined optical power division ratio. The Mach-Zehnder modulator 120 includes a first input end 2a, a second input end 2b, and a modulated optical signal output end 2c, the first input end 2a being connected to the first branch optical path 130, and the second input end 2b being connected to the second branch optical path 140, and configured to receive two branch optical signals, both of which are in the TE mode (or the TM mode), from the first branch optical path 130 and the second branch optical path 140, respectively, and the modulated optical signal output end 2c being configured to output a modulated optical signal, i.e., a composite wave signal output after the two branch optical signals having a target phase difference are modulated by the Mach-Zehnder modulator 120.

[0026] In an embodiment of the present disclosure, the mode separation element 110 (i.e., the TM / TE mode separator) is configured to separate the mixed horizontal and vertical electric and magnetic waves in an input optical signal (e.g., an optical signal transmitted through an optical fiber) and thereby output a TE mode optical signal and a TM mode optical signal via the first output end 1b and the second output end 1c. The optical mode converter 150 is configured to convert the received optical signal from one magnetic wave mode to another magnetic wave mode and output an optical signal having the same magnetic wave mode as the magnetic wave mode of the other branch optical path. The phase modulation module 160 is configured to modulate the phase difference between the first branch optical path 130 and the second branch optical path 140 based on a predetermined optical power division ratio so that the two branch optical signals have a target phase difference corresponding to the optical power division ratio when they arrive at the first input end 2a and the second input end 2b of the Mach-Zehnder modulator 120, thereby satisfying the operating input requirements of the Mach-Zehnder modulator 120. For example, the optical power is distributed to the first branch optical path 130 and the second branch optical path 140 according to a ratio of 100% and 0%, respectively, and after modulation by the phase modulation module 160, the phases of the first branch optical path and the second branch optical path differ by an even multiple of Π.

[0027] 1, the basic structure of the Mach-Zehnder modulator 120 includes an optical splitting module 121, an optical combining module 122, two waveguide arms 123 and 124, and a modulating electrode 125. In the embodiment of the present disclosure, the optical splitting module 121 includes a first input end 2a and a second input end 2b, and the optical combining module 122 includes an output end 2c of the modulated optical signal.

[0028] The basic operating principle of the Mach-Zehnder modulator 120 is as follows: the modulation electrode 125 applies a modulation voltage to the two waveguide arms 123, 124, changing the refractive index of the material of the waveguide arms, which in turn changes the phase of the optical signal transmitted in the waveguide arms. The light transmitted in the two waveguide arms 123, 124 may differ in phase by an odd or even multiple of Π when it reaches the optical combining module 122. If the phase differs by an even multiple of Π, the optical combining module 122 outputs a signal that is reinforced by interference, and if the phase differs by an odd multiple of Π, the optical combining module 122 outputs a signal that is canceled by interference.

[0029] 1, in some embodiments, the two branched optical signals of the same mode arriving at the first input end 2 a and the second input end 2 b are both TE mode optical signals, and the second branched optical path 140 is provided with an optical mode converter 150 for converting the TM mode optical signal into a TE mode optical signal. That is, the light is in TM mode when input to the optical mode converter 150, and is in TE mode when output from the optical mode converter 150.

[0030] 2, in some other embodiments, the two branched optical signals of the same mode arriving at the first input end 2 a and the second input end 2 b are both optical signals in TM mode, and the first branched optical path 130 is provided with an optical mode converter 150 for converting the optical signal in TE mode into an optical signal in TM mode. That is, the light is in TE mode when input to the optical mode converter 150, and is in TM mode when output from the optical mode converter 150.

[0031] The specific conversion function of the optical mode converter 150 can be determined according to the requirements of the photonic chip for the operating signal. For example, if the photonic chip requires an operating signal in TE mode, the optical mode converter 150 is configured to convert the TM mode optical signal separated by the mode separation element 110 into a TE mode optical signal. For example, if the photonic chip requires an operating signal in TM mode, the optical mode converter 150 is configured to convert the TE mode optical signal separated by the mode separation element 110 into a TM mode optical signal.

[0032] The optical mode modulator 100 according to the embodiment of the present disclosure is applied in a photonic chip, which enables the input optical signal to be modulated to obtain an operating signal with high modal purity, thereby improving the operating performance of the photonic chip and reducing the optical transmission loss in the photonic chip.

[0033] 1 and 2, in some embodiments of the present disclosure, the phase modulation module 160 includes a first phase modulator 161 provided in the first branch optical path 130 and / or a second phase modulator 162 provided in the second branch optical path 140. The first phase modulator 161 and the second phase modulator 162 may be, for example, an electro-optic phase modulator or a thermo-optic phase modulator, but are not specifically limited in the present disclosure.

[0034] In the embodiment of the present disclosure, the phase modulation may be performed on the optical signal of either branch optical path, or on the optical signals of both branch optical paths, but the present disclosure is not specifically limited thereto.

[0035] 3, in some embodiments of the present disclosure, the optical mode modulator 100 further includes an optical splitting element 170 and a monitoring sensor 180. The optical splitting element 170 includes an input end 7a, a third output end 7b, and a fourth output end 7c of the optical splitting element, where the input end 7a of the optical splitting element is connected to the output end 2c of the modulated optical signal, the third output end 7b is configured to output an operating signal, and the fourth output end 7c is configured to output a monitoring signal. The monitoring sensor 180 is configured to detect the signal strength of the monitoring signal.

[0036] In the embodiment of the present disclosure, the optical splitting element 170 refers to an optical power distribution element, for example, a multi-mode interference element having an optical power distribution function.

[0037] According to the design of the embodiment, the input optical signal received by the optical mode modulator 100 and the operating state of the optical mode modulator 100 can be effectively monitored, and the phase modulation module 160 and the modulation electrode 125 of the Mach-Zehnder modulator 120 are compensated and modulated according to the signal strength of the monitoring signal obtained from the fourth output end 7c, thereby improving the accuracy of the operating signal output from the third output end 7b.

[0038] 4, in some embodiments, the optical mode modulator 100 further includes a feedback module 190. The feedback module 190 is separately connected to the monitoring sensor 180, the phase modulation module 160, and the modulation electrode 125 of the Mach-Zehnder modulator 120, and is configured to output a first feedback signal to the phase modulation module 160 and a second feedback signal to the modulation electrode 125 of the Mach-Zehnder modulator 120 based on the signal strength of the monitoring signal. Depending on the design of the embodiment, as long as the operating signal meets the output accuracy requirements, the monitoring sensor 180 can detect the intensity of the monitoring signal in real time or according to a regular cycle, and the feedback module 190 can perform dynamic compensation control on the phase modulation module 160 and the modulation electrode 125.

[0039] Referring to FIG. 2 , an embodiment of the present disclosure further includes an optical mode modulation device 100 including a mode separation element 110, a first branch optical path 130, a second branch optical path 140, a phase modulation module 160, and a Mach-Zehnder modulator 120. The mode separation element 110 is configured to receive an input optical signal and separate the optical signal into a first optical signal of a first mode and a second optical signal of a second mode. The first branch optical path 130 and the second branch optical path 140 are configured to receive the first optical signal and the second optical signal output by the mode separation element 110, respectively. The first branch optical path 130 is provided with an optical mode converter 150 for converting the first optical signal from the first mode to the second mode. The phase modulation module 160 is configured to modulate the phase difference between the first branch optical path 130 and the second branch optical path 140 based on a predetermined optical power division ratio. The Mach-Zehnder modulator 120 is configured to receive a first optical signal and a second optical signal, both of which are in a second mode, from the first branch optical path 130 and the second branch optical path 140, modulate the first optical signal and the second optical signal, and output a modulated optical signal. The first mode and the second mode may each be a TE mode or a TM mode.

[0040] In some embodiments, the optical mode modulation device 100 further includes a phase modulation module 160. The phase modulation module 160 includes a first phase modulator (not shown) disposed in the first optical branch 130 and / or a second phase modulator 162 disposed in the second optical branch 140.

[0041] In an embodiment, the optical mode modulator 100 is applied in a photonic chip, thereby enabling to improve the operation performance of the photonic chip and reduce the transmission loss of light in the photonic chip.

[0042] 5, an embodiment of the present disclosure further provides a photonic chip 1 including an optical mode modulator 100 according to any one of the above-described embodiments, wherein the above-described mode separation element 110 of the optical mode modulator 100 is configured to be optically coupled to an optical fiber. In addition to the optical mode modulator 100, the optical chip 1 may further include one or more devices thereon, such as an electro-optic modulator, a splitter, a star coupler, a variable optical attenuator (VOA), an optical switch, a frequency comb, and an arrayed waveguide grating (AWG), which are not shown in the figure.

[0043] Because the optical mode modulator 100 has the above beneficial effects, the operation performance of the photonic chip 1 can be significantly improved thereby, and the transmission loss is also significantly reduced.

[0044] In this description, the orientations, positional relationships, or dimensions indicated by words such as "center," "vertical," "horizontal," "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 words are used merely for the purpose of succinct description, rather than indicating or implying that the referred to device or element must have a particular orientation or be configured and operated in a particular orientation, and therefore should not be construed as limiting the protection scope of the present disclosure.

[0045] Additionally, terms such as "first," "second," and "third" are for descriptive purposes only and should not be construed as denoting or implying relative importance or the number of technical features to which they refer. Thus, features qualified by "first," "second," and "third" may explicitly or implicitly include one or more features. In the description of this disclosure, the term "a plurality of" means two or more, unless expressly and specifically defined otherwise.

[0046] In this disclosure, unless expressly stated or specifically defined otherwise, terms such as "attach," "connect," "connected," and "secure" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an 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 between two elements, or an interactive relationship between two elements. For those skilled in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0047] In this disclosure, unless expressly stated or specifically defined otherwise, the phrase "above" or "below" a first feature may include cases where the first feature is in direct contact with the second feature, or cases where the first feature is not in direct contact with the second feature but is in contact with the second feature through another feature between them. Furthermore, a first feature being "over," "above," or "on" a second feature includes cases where the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal position than the second feature. A first feature being "below," "under," or "beneath" a second feature includes cases where the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal position than the second feature.

[0048] 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 can think of various modifications or substitutions. All of 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 mode separation element having an optical signal input end, a first output end, and a second output end, the optical signal input end configured to receive an input optical signal, the first output end configured to output an optical signal in TE mode, and the second output end configured to output an optical signal in TM mode; a first branch optical path and a second branch optical path, the first branch optical path being connected to the first output end and the second branch optical path being connected to the second output end, the first branch optical path being provided with an optical mode converter for converting the TE mode optical signal to the TM mode optical signal, or the second branch optical path being provided with an optical mode converter for converting the TM mode optical signal to the TE mode optical signal; a phase modulation module configured to modulate a phase difference between the first branch optical path and the second branch optical path based on a predetermined optical power division ratio; a Mach-Zehnder modulator having a first input end, a second input end, and an output end for modulated optical signals, the first input end being connected to the first branch optical path, and the second input end being connected to the second branch optical path, and receiving two branch optical signals, both of which are in TE mode or TM mode, from the first branch optical path and the second branch optical path, respectively; 1. An optical mode modulation device comprising:

2. 2. The optical mode modulation device according to claim 1, wherein the two branched optical signals output from the first branched optical path and the second branched optical path, respectively, are both optical signals in the TE mode, and the second branched optical path is provided with the optical mode converter for converting the optical signal in the TM mode into the optical signal in the TE mode.

3. 2. The optical mode modulation device according to claim 1, wherein the two branched optical signals output from the first branched optical path and the second branched optical path, respectively, are both optical signals in the TM mode, and the first branched optical path is provided with the optical mode converter for converting the optical signal in the TE mode into the optical signal in the TM mode.

4. 2. The optical mode modulation device of claim 1, wherein the phase modulation module comprises a first phase modulator provided in the first branch optical path and / or a second phase modulator provided in the second branch optical path.

5. 5. The optical mode modulation device of claim 4, wherein the phase modulation module is an electro-optic phase modulation module or a thermo-optic phase modulation module.

6. an optical dividing element having an input end, a third output end, and a fourth output end of the optical dividing element, wherein the input end of the optical dividing element is connected to the output end of the modulated optical signal, the third output end is configured to output an operating signal, and the fourth output end is configured to output a supervisory signal; a monitoring sensor configured to detect a signal strength of the monitoring signal; 5. The optical mode modulator of claim 4, further comprising:

7. 7. The optical mode modulation device of claim 6, further comprising a feedback module separately connected to the monitoring sensor and the phase modulation module, and configured to output a first feedback signal to the phase modulation module and a second feedback signal to a modulation electrode of the Mach-Zehnder modulator based on the signal strength of the monitoring signal.

8. a mode separation element configured to receive an input optical signal and separate the optical signal into a first optical signal in a first mode and a second optical signal in a second mode; a first branch optical path and a second branch optical path configured to receive the first optical signal and the second optical signal output by the mode separation element, respectively, the first branch optical path being provided with an optical mode converter for converting the first optical signal from the first mode to the second mode; a phase modulation module configured to modulate a phase difference between the first branch optical path and the second branch optical path based on a predetermined optical power division ratio; a Mach-Zehnder modulator configured to receive the first optical signal and the second optical signal, both of which are in the second mode, from the first branch optical path and the second branch optical path, and to modulate the first optical signal and the second optical signal to output a modulated optical signal; 1. An optical mode modulation device comprising:

9. 9. The optical mode modulation device of claim 8, wherein the phase modulation module comprises a first phase modulator provided in the first branch optical path and / or a second phase modulator provided in the second branch optical path.

10. 10. A photonic chip comprising the optical mode modulator of claim 1, wherein the mode separation element of the optical mode modulator is configured to be optically coupled to an optical fiber.

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