Electro-optical modulator and electro-optical modulation device

Abstract

The application provides an electro-optical modulator and an electro-optical modulation device, wherein the electro-optical modulator comprises a first waveguide modulation module, a second waveguide modulation module and an electrical signal driving module; the electrical signal driving module is used for providing m-level electrical signals to the first waveguide modulation module and the second waveguide modulation module for electro-optical conversion; the first waveguide modulation module and the second waveguide modulation module each comprise m-level slow wave waveguides; the i-th level slow wave waveguide in the first waveguide modulation module and the second waveguide modulation module each receives the i-th level electrical signal in the m-level electrical signals and modulates the i-th level electrical signal to the optical domain; wherein the time for the i+1-th level electrical signal in the electrical signal driving module to reach the i+1-th level slow wave waveguide is greater than the time for the i-th level electrical signal to reach the i-th level slow wave waveguide; m is an integer greater than or equal to 2; i is greater than or equal to 1 and less than or equal to m-1. The application guarantees the speed matching between the optical wave and the electrical signal, and realizes the electro-optical modulator with large bandwidth, high modulation efficiency and high integration.

Description

Technical Field

[0001] This invention relates to the field of high-speed optical signal transceiver, and in particular to an electro-optic modulator and electro-optic modulation device. Background Technology

[0002] With the widespread deployment of information technologies such as cloud computing, big data, and artificial intelligence, the global data volume is surging exponentially. Electro-optic modulators, as key components for converting electrical signals into optical signals, play a central role in information transmission and processing. Therefore, improving the performance indicators of electro-optic modulators, such as operating bandwidth and modulation efficiency, has always been a key research objective. Currently, the rapidly growing transmission capacity of fiber optic backbone networks necessitates that electro-optic modulators possess greater modulation bandwidth and higher modulation efficiency.

[0003] The Mach-Zehnder interferometer (MZI) is an optical device widely used in optical signal processing. Its core principle lies in modulating light waves by utilizing the phase difference generated in two interfering paths (i.e., the two arms of the interferometer). In a Mach-Zehnder interferometer, electro-optic modulation is achieved by applying an electrical signal to the waveguides of the two arms. To improve the modulator's bandwidth, designers typically employ traveling-wave electrodes. The design of traveling-wave electrodes allows the electrical signal to propagate along the electrodes in wave form, thus enabling more effective interaction with the light wave.

[0004] However, as the modulation speed increases, a mismatch still exists between the group velocity of light (the propagation speed of the light wave envelope) and the speed of the electrical signal, resulting in asynchronous phase modulation of the light wave, affecting the performance of the modulator, and causing a decrease in bandwidth.

[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an electro-optic modulator and electro-optic modulation device to solve the problem that, as the modulation speed increases, the electrodes of the traveling wave structure still have a mismatch between the group velocity of light and the speed of the electrical signal.

[0007] To achieve the above and other related objectives, the present invention provides an electro-optic modulator, comprising:

[0008] The first waveguide modulation module receives a first sub-optical signal, the second waveguide modulation module receives a second sub-optical signal, and the electrical signal driving module is used to provide an m-level electrical signal to the first waveguide modulation module and the second waveguide modulation module for electro-optical conversion.

[0009] Both the first waveguide modulation module and the second waveguide modulation module include m-level slow waveguides. The i-th level slow waveguide in both the first and second waveguide modulation modules receives the i-th level electrical signal from the m-level electrical signal and modulates it into the optical domain. In the electrical signal driving module, the time for the (i+1)-th level electrical signal to reach the (i+1)-th level slow waveguide is greater than the time for the i-th level electrical signal to reach the i-th level slow waveguide. m is an integer greater than or equal to 2, and i is greater than or equal to 1 and less than or equal to m-1.

[0010] Optionally, the electro-optic modulator further includes an optical beam splitter, an optical beam combiner, and a phase adjustment module; the optical beam splitter is used to split the received optical signal into a first sub-optical signal and a second sub-optical signal; the first sub-optical signal enters the phase adjustment module through the first waveguide modulation module and enters the optical beam combiner after phase adjustment; the second sub-optical signal enters the optical beam combiner after passing through the second waveguide modulation module; the optical beam combiner combines the two received optical signals.

[0011] Optionally, the slow waveguide includes at least one structure, such as a photonic crystal structure and a periodic grating structure.

[0012] Optionally, the i-th stage electrical signal provided by the electrical signal driving module to the i-th stage slow waveguide in the first waveguide modulation module and the i-th stage electrical signal provided by the electrical signal driving module to the i-th stage slow waveguide in the second waveguide modulation module are the same electrical signal. The slow waveguide includes at least one modulation structure among PN junction modulation structure, PIN junction modulation structure and MOS modulation structure.

[0013] Optionally, when the slow wave waveguide includes a PN junction modulation structure, the i-th stage slow wave waveguide in the first waveguide modulation module serves as the first modulation PN junction, and the i-th stage slow wave waveguide in the second waveguide modulation module serves as the second modulation PN junction; the i-th stage electrical signal is sequentially applied to the first modulation PN junction and the second modulation PN junction.

[0014] Optionally, when the slow wave waveguide includes a PN junction modulation structure, the i-th stage slow wave waveguide in the first waveguide modulation module serves as the third modulation PN junction, and the i-th stage slow wave waveguide in the second waveguide modulation module serves as the fourth modulation PN junction; the i-th stage electrical signal is applied to the third modulation PN junction and the fourth modulation PN junction respectively.

[0015] Optionally, the electrical signal driving module includes m-1 segmented signal delay units and 2m electrical connection parts; each electrical connection part is configured one-to-one with each slow waveguide, used to receive the corresponding electrical signal and modulate the refractive index of the corresponding slow waveguide; each segmented signal delay unit is connected in series; the input terminal of the first-stage segmented signal delay unit receives the first-stage electrical signal, delays it, and outputs it at the output terminal; the input terminal of the j-th stage segmented signal delay unit receives the electrical signal output from the j-1 stage, delays it, and outputs it at the output terminal, where j is an integer greater than 1 and less than or equal to m-1.

[0016] Optionally, the segmented signal delay unit includes a delay section; the delay section includes wires arranged in a sinusoidal waveform; the first end of the wires serves as the input end of the segmented signal delay unit, and the second end serves as the output end of the segmented signal delay unit.

[0017] Optionally, the segmented signal delay unit includes an electrical delay device; the electrical delay device includes a resistor and a capacitor; the first end of the resistor serves as the input end of the segmented signal delay unit, and the second end serves as the output end of the segmented signal delay unit; the first end of the capacitor is connected to the second end of the resistor, and the second end is connected to a reference ground.

[0018] Optionally, the electrical signal driving module further includes m electrical signal power compensation units; each electrical signal power compensation unit is configured to correspond one-to-one with each level of electrical signal, and is used to compensate for the power of each level of electrical signal.

[0019] Optionally, the electrical signal power compensation unit is configured as an electrical amplifier; the input terminal of the electrical amplifier is connected to the corresponding electrical signal, and the output terminal is connected to the corresponding electrical connection parts at each stage.

[0020] Optionally, the electrical signal driving module further includes a preamplifier and / or a matching unit; the preamplifier receives the input electrical signal and outputs a first-stage electrical signal to increase the strength of the input electrical signal; the first end of the matching unit is connected to the m-th stage electrical signal, and the second end is connected to a reference ground.

[0021] To achieve the above and other related objectives, the present invention provides an electro-optic modulation device, including the electro-optic modulator described above; wherein the first waveguide modulation module and the second waveguide modulation module are designed on different chips from the electrical signal driving module, or the first waveguide modulation module, the second waveguide modulation module and the electrical signal driving module are designed on the same chip.

[0022] As described above, the electro-optic modulator and electro-optic modulation device of the present invention have the following beneficial effects:

[0023] 1. This invention adjusts the signal delay by setting an electrical signal driving module to ensure the matching between the group velocity of light and the electrical signal velocity in the electro-optic modulator as the modulation speed increases, thus guaranteeing better bandwidth. Compared with ordinary waveguides, this invention has higher modulation efficiency and a more compact structure, which can effectively reduce the half-wave voltage of the electro-optic modulator and achieve higher modulation speed.

[0024] 2. The electrical signal driving module of the present invention is configured as a single signal driving two waveguide modules, which reduces the complexity of the device and the power consumption, and has better application prospects.

[0025] 3. The electrical signal driving module of the present invention also compensates for the attenuation of the signal during the propagation process, thus solving the attenuation problem in the transmission of electrical signals. Attached Figure Description

[0026] Figure 1 The diagram shown is a schematic of a Mach-Zehnder interferometer structure.

[0027] Figure 2 The diagram shows a frame of the electro-optic modulator of the present invention.

[0028] Figure 3 The image shown is a top view of the first slow waveguide of the present invention.

[0029] Figure 4 The image shown is a top view of the second type of slow waveguide of the present invention.

[0030] Figure 5 This invention is shown as Figure 5 Cross-sectional view of the slow waveguide.

[0031] Figure 6 The diagram shown is a structural schematic of an electro-optic modulator according to the present invention.

[0032] Figure 7 The diagram shows the connection of the slow waveguides of the first type of PN junction modulation structure of the present invention.

[0033] Figure 8 This invention is shown as Figure 7 A schematic diagram of the electrical signal input to the slow waveguide.

[0034] Figure 9 This invention is shown as Figure 7 Cross-sectional view of the slow waveguide.

[0035] Figure 10 The diagram shown is a structural schematic of another electro-optic modulator of the present invention.

[0036] Figure 11 The diagram shows a slow waveguide with two PN junction modulation structures, representing another embodiment of the present invention.

[0037] Figure 12 This invention is shown as Figure 11 Cross-sectional view of the slow waveguide.

[0038] Figure 13 The diagram shown is a structural schematic of the delay section of the present invention.

[0039] Figure 14 The diagram shown is a structural schematic of the electrical delay device of the present invention.

[0040] Figure 15 The diagram shown is a structural schematic of the first electro-optic modulation device of the present invention.

[0041] Figure 16 The diagram shown is a structural schematic of the second type of electro-optic modulation device of the present invention.

[0042] Component designation explanation

[0043] 1. Structure of the Mach-Zehnder Interferometer

[0044] 11. Optical beam splitter

[0045] 12 Modulation Arm

[0046] 13. Optical beam combiner

[0047] 2 Electro-optic modulator

[0048] 201 First Chip

[0049] 202 Second Chip

[0050] 203 Third Chip

[0051] 21. Optical beam splitter

[0052] 22. Optical beam combiner

[0053] 23 First Waveguide Modulation Module

[0054] 231 Slow Waveguide

[0055] 231' photonic crystal structure

[0056] 231” periodic grating structure

[0057] 231a First Modulation PN Junction

[0058] 231b Second Modulated PN Junction

[0059] 231c Third Modulation PN Junction

[0060] 231d Fourth Modulated PN Junction

[0061] 24 Second Waveguide Modulation Module

[0062] 25 Phase Adjustment Module

[0063] 26 Electrical signal drive module

[0064] 261 Electrical Connections

[0065] 2611 First Electrical Connection

[0066] 2612 Second Electrical Connection

[0067] 262 segmented signal delay unit

[0068] 262a Delay Unit

[0069] 262b Electrical Delay Unit

[0070] 263 Electrical signal power compensation unit

[0071] 264 Preamplifier Detailed Implementation

[0072] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0073] Please see Figures 1 to 16 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0074] Comparative Example

[0075] like Figure 1As shown, a Mach-Zehnder interferometer structure 1 includes: an optical beamsplitter 11, two modulation arms 12, and an optical beam combiner 13. The two modulation arms 12 include two optical transmission waveguides and two electrodes. The optical beamsplitter 11 is used to split the optical signal into two sub-optical signals, which are then input to the input ports of the two optical transmission waveguides respectively. The two electrodes include a first electrode and a second electrode, which are used to receive two differential electrical signals and apply these two electrical signals to the two optical transmission waveguides to change the phase of the two sub-optical signals. The two input terminals of the optical beam combiner are connected to the output ports of the two optical transmission waveguides respectively, and are used to interfere with the phase-changed optical signals after passing through the two modulation arms before outputting them. By applying electrical signals, the two modulation arms of the Mach-Zehnder interferometer structure 1 generate a phase difference, thereby modulating the optical signal. In this comparative example, to improve bandwidth, the two electrodes are configured as traveling wave electrodes (TWE). Traveling-wave electrodes allow electrical signals to propagate in a traveling-wave pattern within the electrode structure, meaning the electrical signal propagates in the same direction as the optical signal, thus matching the speeds of the two signals. Furthermore, previous electrical signal transmission methods required transmitting a pair of differential signals, which increased the design complexity and power consumption of the electrical amplifier.

[0076] Example

[0077] To solve the above problems, such as Figure 2 As shown, this embodiment provides an electro-optic modulator 2, including a first waveguide modulation module 23, a second waveguide modulation module 24, and an electrical signal driving module 26.

[0078] like Figure 2 As shown, the electro-optic modulator 2 in this embodiment also includes an optical beam splitter 21, an optical beam combiner 22, and a phase adjustment module 25.

[0079] like Figure 2 As shown, the optical beam splitter 21 is used to split the received optical signal into a first sub-optical signal and a second sub-optical signal.

[0080] Specifically, in this embodiment, the optical signal is coherent light. Meanwhile, the optical beam splitter 21 is provided, including but not limited to directional coupler type optical beam splitters, multimode interference type optical beam splitters, etc. In this embodiment, the optical beam splitter 21 is used to split the coherent light into two sub-coherent beams.

[0081] like Figure 2As shown, the first waveguide modulation module 23 and the phase adjustment module 25 are connected in sequence; the first sub-optical signal enters the phase adjustment module 25 through the first waveguide modulation module 23 and is then phase-modulated before entering the optical combiner 22. The second waveguide modulation module 24 receives the second sub-optical signal; the second sub-optical signal enters the optical combiner 22 after passing through the second waveguide modulation module 24.

[0082] Specifically, both the first waveguide modulation module 23 and the second waveguide modulation module 24 include m-level slow waveguides 231. m is an integer greater than or equal to 2. That is to say, the first waveguide modulation module and the second waveguide modulation module require at least 4 slow waveguides.

[0083] More specifically, the slow-wave waveguide 231 includes, but is not limited to, a photonic crystal structure 231a and a periodic grating structure 231b. Among them, such as... Figure 3 As shown, photonic crystal structure 231a has a photonic bandgap and is formed by two or more media with different dielectric constants arranged in a certain periodic pattern in space. For example... Figure 4 and Figure 5 As shown, the periodic grating structure 231b refers to an optical waveguide structure composed of a series of protrusions or grooves, capable of achieving periodic refractive index changes. In this embodiment, the slow-wave waveguide 231 can also be configured as a combination of the photonic crystal structure 231a and the periodic grating structure 231b, or as a variant of the photonic crystal structure 231a, a variant of the periodic grating structure 231b, or a combination of both variant structures. Furthermore, the slow-wave waveguide 231 can be adapted to other waveguide structures, as long as it achieves a slower group velocity compared to other ordinary waveguides to increase the interaction time between light and materials, all of which fall within the scope of this embodiment.

[0084] It should be noted that, since multiple slow waveguides 231 are configured in this embodiment, they have better modulation efficiency. Compared with ordinary optical waveguides, slow waveguides 231 have a slower light group velocity, which increases the interaction time between light and materials. Therefore, compared with electro-optic modulators based on ordinary waveguides, this embodiment has higher modulation efficiency and is also conducive to reducing device size.

[0085] More specifically, the i-th stage electrical signal provided by the electrical signal driving module 26 to the i-th stage slow waveguide in the first waveguide modulation module 23 and the i-th stage electrical signal provided by the electrical signal driving module 26 to the i-th stage slow waveguide in the second waveguide modulation module 24 are the same electrical signal. In this embodiment, the electrical signal is a voltage signal. The slow waveguide 231 includes at least one modulation structure selected from PN junction modulation structure, PIN junction modulation structure, and MOS modulation structure. The modulation structure refers to the configuration of the slow waveguide 231 during electro-optic modulation. For example, if it is set to PN junction type, it means that it needs to set one P-region and one N-region for subsequent modulation. The PIN junction modulation structure and MOS modulation structure will not be described further here.

[0086] When the slow waveguide 231 includes a PN junction modulation structure, as a first example, such as Figure 6 , Figure 7 , Figure 8 as well as Figure 9 As shown, the i-th stage slow waveguide 231 in the first waveguide modulation module 23 serves as the first modulation PN junction 231a; the i-th stage slow waveguide in the second waveguide modulation module 24 serves as the second modulation PN junction 231b; the i-th stage electrical signal is sequentially applied to the first modulation PN junction 231a and the second modulation PN junction 231a. The voltages of the two modulation PN junctions share the i-th stage electrical signal, and the specific voltage amplitudes are correspondingly reduced. The PN junction modulation structure is a structure formed by the contact of P-type semiconductors and N-type semiconductors, that is, different doping on both sides of the slow waveguide to form a space charge region (depletion region) at the interface. When an external voltage (bias region) is applied, the width of this depletion region can be changed, thereby changing the distribution of charge carriers and thus changing the refractive index of the waveguide.

[0087] As a further example, the electrical signal driving module 26 also includes a first bias voltage power supply unit (not shown in the figure); the first bias voltage power supply unit is used to provide a first bias voltage.

[0088] In this embodiment, when the configuration of the first waveguide modulation module 23 and the second waveguide modulation module 24 corresponding to the i-th stage slow wave waveguide 231 is set in a push-pull manner, the P terminal of the first modulation PN junction 231a is connected to the i-th stage electrical signal, the N terminal receives the first bias voltage and is connected to the N terminal of the second modulation PN junction 231b, and the P terminal of the second modulation PN junction 231b is connected to the reference ground (e.g., ...). Figure 9As shown, this "PNNP" type configuration ensures reverse bias by applying a first bias voltage to the N-terminus of the first modulation PN junction. It can also be configured as an "NPPN" type as needed. In practice, the location of the first bias voltage application can be set according to actual needs, as long as each PN junction in the first modulation PN junction 231a and the second modulation PN junction 231b is reverse biased, which constitutes the protection range of this embodiment. Furthermore, the first bias voltage can also originate from other power supply sources and is not limited to the implementation method in this embodiment.

[0089] It should be noted that, in order to save device area, in this embodiment, the same level of electrical signal is preferably set as the same signal to drive the two corresponding slow waveguides 231 for modulation at the same time. However, in practical applications, the same level of electrical signal can also be selected as two electrical signals (such as differential form) to modulate the two slow waveguides 231 based on actual needs.

[0090] When the slow waveguide 231 includes a PN junction modulation structure, in the second example, the i-th stage slow waveguide in the first waveguide modulation module 23 serves as the third modulation PN junction 231c; the i-th stage slow waveguide in the second waveguide modulation module 24 serves as the fourth modulation PN junction 231d; the i-th stage electrical signal reaches the reference ground via the third modulation PN junction 231c, and the i-th stage electrical signal reaches the reference ground via the fourth modulation PN junction 231d, which is equivalent to introducing the i-th stage electrical signal into the two corresponding slow waveguides 231 in a "parallel" manner (e.g., ...). Figure 12 (As shown).

[0091] In this embodiment, the electrical signal driving module 26 further includes a second bias voltage power supply unit (not shown in the figure); the second bias voltage power supply unit is used to provide a second bias voltage, and the second bias signal is introduced at the i-th stage electrical signal input terminal of the third modulation PN junction 231c or the reference ground is changed to the second bias voltage, which is not limited to this embodiment.

[0092] In this embodiment, when the configuration between the first waveguide modulation module 23 and the second waveguide modulation module 24 corresponding to the i-th stage slow waveguide 231 is set in a differential configuration, the P-terminal of the third modulation PN junction 231c is connected to the reference ground, and the N-terminal is connected to the i-th stage electrical signal; the P-terminal of the fourth modulation PN junction 231d is connected to the i-th stage electrical signal, and the N-terminal is connected to the reference ground.

[0093] It should be noted that the configuration between the i-th stage slow wave waveguide 231 in the first waveguide modulation module 23 and the second waveguide modulation module 24 is not limited to this embodiment. Any configuration that uses the distribution change of charge carriers (i.e., free electrons and holes) in the waveguide material to change the refractive index of the light wave, thereby achieving modulation of the optical signal, is within the protection scope of this embodiment.

[0094] Specifically, the phase adjustment module 25 is configured as an optical phase modulator; a DC bias voltage and a modulation voltage are applied to the optical phase modulator to make the Mach-Zehnder optical interferometer work at the quadrature bias point in order to achieve the best modulation effect.

[0095] like Figure 2 As shown, the electrical signal driving module 26 is used to provide m-level electrical signals to the first waveguide modulation module 23 and the second waveguide modulation module 24 for electro-optic conversion.

[0096] Specifically, in both the first waveguide modulation module 23 and the second waveguide modulation module 24, the i-th level slow waveguide 231 receives the i-th level electrical signal from the m-th level signal provided by the electrical signal driving module 26 and modulates it into the optical domain, modulating the optical signal flowing through it based on the i-th level electrical signal. The time it takes for the (i+1)-th level electrical signal in the electrical signal driving module 25 to reach the (i+1)-th level slow waveguide 231 is greater than the time it takes for the i-th level electrical signal to reach the i-th level slow waveguide 231. m is an integer greater than or equal to 2; i is greater than or equal to 1 and less than or equal to m-1. For example, both the first waveguide modulation module 23 and the second waveguide modulation module 24 are configured as three-level slow waveguides 231, and the corresponding electrical signals should also have three levels. Furthermore, in these three levels of electrical signals, the time it takes for the later electrical signal to reach the corresponding slow waveguide 231 is greater than the time it takes for the previous electrical signal to reach the corresponding slow waveguide 231. It should be noted that, in this embodiment, in order to simplify the electrical signal driving module 26, the subsequent electrical signal can be obtained by delaying the previous electrical signal, that is, multiple electrical signals of different levels can be obtained by sequentially delaying an input electrical signal.

[0097] More specifically, such as Figure 6 and Figure 10 As shown, the electrical signal driving module 26 includes m-1 segmented signal delay units 262 and 2m electrical connection parts 261.

[0098] As an example, each electrical connection 261 is configured in a one-to-one correspondence with each slow waveguide 231, for receiving the corresponding electrical signal and modulating the refractive index of the corresponding slow waveguide 231.

[0099] In this embodiment, the electrical connection 261 is configured as a first electrical connection 2611 and a second electrical connection 2612. By clamping it on both sides of the slow waveguide 231, the distribution of charge carriers is changed, thereby ensuring the effect of electro-optic modulation.

[0100] As an example, in this embodiment, the segmented signal delay units 262 are connected in series. The input of the first-stage segmented signal delay unit receives the first-stage electrical signal, delays it, and outputs the second-stage electrical signal. The input of the j-th stage segmented signal delay unit receives the electrical signal output from stage j-1, delays it, and outputs it. Here, j is an integer greater than 1 and less than or equal to m-1. In other words, in this embodiment, as the transmission length of the sub-optical signal in the slow waveguide increases, the delay of the electrical signal also increases accordingly. The delay time of the electrical signal needs to compensate for the time difference between the optical group signal and the electrical signal in the slow waveguide at a preset length. In this embodiment, it is only required that the time for the (i+1)-th stage electrical signal to reach the (i+1)-th stage slow waveguide 231 is greater than the time for the (i)-th stage electrical signal to reach the (i)-th stage slow waveguide 231, which requires partial compensation. This improves the modulation efficiency and matching degree compared to the setting without compensation. Similarly, it can be seen that the preferred setting of the electrical signal delay time can compensate for the time difference between the slow waveguide 231 and the electrical signal during each stage of transmission, so that the group velocity of light and the transmission speed of electrical signal can be better matched.

[0101] As a first example, such as Figure 13 As shown, the segmented signal delay unit 262 includes a delay section 262a; the delay section 262a includes wires arranged in a sinusoidal waveform; the first end of the wires serves as the input terminal of the segmented signal delay unit 262, receiving the i-th level electrical signal, and the second end serves as the output terminal of the segmented signal delay unit 262, outputting the delayed electrical signal, which is the (i+1)-th level electrical signal. In this embodiment, the delay of the electrical signal is adjusted by setting the length of the wires. In addition, the delay section 262a in this embodiment is set in the form of a sine wave, which can optimize the device layout area and reduce the device size. In fact, the delay section 262a can also be set with wires of other shapes, and delay can be achieved by extending the physical length, and is not limited to the protection scope of this embodiment.

[0102] As a second example, such as Figure 14 As shown, the segmented signal delay unit 262 includes an electrical delay unit 262b; the electrical delay unit 262b includes a resistor R and a capacitor C; the first end of the resistor R serves as the input terminal of the segmented signal delay unit 262, receiving the i-th level electrical signal, and the second end serves as the output terminal of the segmented signal delay unit 262, outputting the delayed electrical signal, which is the (i+1)-th level electrical signal; the first end of the capacitor C is connected to the second end of the resistor R, and the second end is connected to the reference ground. In this example, the delay time (delay time T = R × C) is adjusted by setting the resistor R and the capacitor C. Compared with the first example, the device layout area of ​​the second example is smaller, which is beneficial to improving the device integration density.

[0103] It should be noted that the actual segmented signal delay unit 262 is not limited to this embodiment. Any structure that can delay the electrical signal based on actual requirements is within the protection scope of this embodiment. The connection method between the segmented signal delay units 262 is also not limited to this embodiment. As long as it can be ensured that the electrical signal delay increases with the number of stages of the slow waveguide 231 when each stage of the electrical signal reaches the corresponding slow waveguide 231, it is within the protection scope of this embodiment. At the same time, compared with the previous method in the first waveguide modulation module 23 and the second waveguide modulation module 24, which required a pair of differential electrical signals, this embodiment does not require setting differential electrical signals. It can be based on the same source of electrical signals (obtained by sequentially delaying the first stage electrical signal to the subsequent stages of electrical signals), further improving the integration of the device.

[0104] It should be further explained that the segmented signal delay unit 262 provided in this embodiment effectively avoids the problem of excessive difference between the group velocity of the slow waveguide and the transmission speed of the electrical signal. It is not limited by the electro-optical speed mismatch caused by the slow waveguide 231, and can reduce the half-wave voltage of the modulator to achieve a higher modulation speed.

[0105] As an example, due to the physical layer signal attenuation issue during electrical signal transmission through wires, to avoid insufficient amplitude of the electrical signal input to the corresponding slow-wave waveguide, affecting modulation accuracy, etc., Figures 6-8 as well as Figures 10-11 As shown, the electrical signal driving module also includes m electrical signal power compensation units 263; each electrical signal power compensation unit 263 is configured to correspond one-to-one with each level of electrical signal, and is used to compensate for the attenuation amplitude of each level of electrical signal. Since the electrical signals originate from the same electrical signal and are obtained by delaying through a series of segmented signal delay units, in this embodiment, the electrical signal power compensation unit 263 is configured as an electrical amplifier; the input terminal of the electrical amplifier is connected to the corresponding electrical signal, and the output terminal is connected to the corresponding electrical connection part of each level, thereby increasing the amplitude of the electrical signal by directly amplifying the electrical signal.

[0106] It should be noted that in this embodiment, the compensation for the attenuation amplitude of each level of electrical signal is still full compensation, that is, the signal is restored to the proper amplitude by setting the preset multiple of the electrical amplifier. However, in actual use, the amplification factor may be set to be smaller or larger as needed, and is not limited to the preset multiple in this embodiment.

[0107] As an example, the electrical signal driving module 26 also includes a preamplifier 264; the preamplifier 264 receives the input electrical signal and outputs a first-stage electrical signal to increase the strength of the input electrical signal. The preamplifier can amplify weak input signals, making them less susceptible to loss during transmission or processing. Simultaneously, it is preferable to amplify the signal near the signal source (input electrical signal) to reduce noise introduced during signal transmission. In practical applications, if the strength of the input electrical signal is sufficiently high, the preamplifier 264 can be omitted to simplify the modulator structure and reduce device power consumption.

[0108] As an example, the electrical signal driving module 26 also includes a matching unit; the first end of the matching unit is connected to the m-th stage electrical signal (the final stage signal), and the second end is connected to the reference ground. In this embodiment, the matching unit is set as a matching resistor Rz to ensure impedance matching between the first waveguide modulation module 23, the second waveguide modulation module 24 and the signal source, avoid signal reflection, and improve signal transmission efficiency.

[0109] like Figure 2 As shown, the optical beam combiner 22 is used to combine two received signals.

[0110] Specifically, in this embodiment, the optical combiner 22 performs interference combining on the two received sub-optical signals that have been modulated differently. This interference can be constructive or destructive, depending on the phase difference between the two sub-optical signals. In this way, the optical combiner converts the phase change of the optical signal into a change in optical intensity, which is convenient for subsequent applications.

[0111] It should be noted that the electro-optic modulator 2 provided in this embodiment has high modulation efficiency, reduces device size, and increases extinction ratio; at the same time, it greatly reduces the design difficulty of the electrical amplifier and reduces device power consumption; the high modulation efficiency of this embodiment can make full use of the advantages of slow waves to reduce half-wave voltage. Therefore, the electro-optic modulator of this embodiment has technical advantages such as large bandwidth, high modulation efficiency, and high integration, and has good market prospects.

[0112] like Figure 15 As shown, this embodiment also provides an electro-optic modulation device, including the electro-optic modulator 2 described above.

[0113] Specifically, the first waveguide modulation module 23 and the second waveguide modulation module 24 are disposed on different chips from the electrical signal driving module 26, or the first waveguide modulation module 23, the second waveguide modulation module 24 and the electrical signal driving module 26 are disposed on the same chip.

[0114] As a first example, the first waveguide modulation module 23 and the second waveguide modulation module 24 are disposed on the first chip 201; the electrical signal driving module 26 is disposed on the second chip 202.

[0115] In this embodiment, the optical beam splitter 21, optical beam combiner 22, first waveguide modulation module 23, second waveguide modulation module 24, and phase adjustment module 25 are all disposed on the first chip 201; the electrical signal driving module 26 is disposed on the second chip 202. In this configuration, the first chip 201 serves as the optical chip and the second chip 202 serves as the electrical chip. After the optical chip and the electrical chip are manufactured separately, they are attached to a substrate and transmitted signals by wire bonding.

[0116] As a second example, the first waveguide modulation module 23, the second waveguide modulation module 24, and the electrical signal driving module 26 are all mounted on the third chip 203.

[0117] In this embodiment, the optical beam splitter 21, optical beam combiner 22, first waveguide modulation module 23, second waveguide modulation module 24, phase adjustment module 25, and electrical signal driving module 26 are all disposed on the third chip 203. In this arrangement, photoelectric signals are fused, that is, optical components and electrical components are fabricated on the same wafer.

[0118] In summary, this invention provides an electro-optic modulator and an electro-optic modulation device. The electro-optic modulator includes a first waveguide modulation module, a second waveguide modulation module, and an electrical signal driving module. The electrical signal driving module provides an m-level electrical signal to the first and second waveguide modulation modules for electro-optic conversion. Both the first and second waveguide modulation modules include m-level slow-wave waveguides. The i-th level slow-wave waveguides in both modules receive the i-th level electrical signal from the m-level electrical signal and modulate the optical signal flowing through them based on the corresponding electrical signal. The time for the (i+1)-th level electrical signal to reach the (i+1)-th level slow-wave waveguide in the electrical signal driving module is greater than the time for the i-th level electrical signal to reach the i-th level slow-wave waveguide. m is an integer greater than or equal to 2, and i is greater than or equal to 1 and less than or equal to m-1. This invention ensures the matching between the optical group velocity and the electrical signal, realizing a high-bandwidth, high-modulation-efficiency, and highly integrated electro-optic modulator. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0119] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An electro-optic modulator, characterized in that, The electro-optic modulator includes at least: a first waveguide modulation module, a second waveguide modulation module, and an electrical signal driving module; The first waveguide modulation module receives a first sub-optical signal, the second waveguide modulation module receives a second sub-optical signal, and the electrical signal driving module is used to provide an m-level electrical signal to the first waveguide modulation module and the second waveguide modulation module for electro-optical conversion. Both the first waveguide modulation module and the second waveguide modulation module include m-level slow waveguides. The i-th level slow waveguide in both the first and second waveguide modulation modules receives the i-th level electrical signal from the m-level electrical signal and modulates it into the optical domain. In the electrical signal driving module, the time for the (i+1)-th level electrical signal to reach the (i+1)-th level slow waveguide is greater than the time for the i-th level electrical signal to reach the i-th level slow waveguide. m is an integer greater than or equal to 2, and i is greater than or equal to 1 and less than or equal to m-1.

2. The electro-optic modulator according to claim 1, characterized in that: The electro-optic modulator also includes an optical beam splitter, an optical beam combiner, and a phase adjustment module; The optical beam splitter is used to split the received optical signal into a first sub-optical signal and a second sub-optical signal; the first sub-optical signal enters the phase adjustment module through the first waveguide modulation module and enters the optical beam combiner after phase adjustment. The second sub-optical signal enters the optical beam combiner after passing through the second waveguide modulation module; The optical combiner combines the two received optical signals.

3. The electro-optic modulator according to claim 1, characterized in that: The slow waveguide includes at least one structure, such as a photonic crystal structure and a periodic grating structure.

4. The electro-optic modulator according to claim 1, characterized in that: The electrical signal driving module provides the i-th stage electrical signal to the i-th stage slow waveguide in the first waveguide modulation module and the electrical signal driving module provides the i-th stage electrical signal to the i-th stage slow waveguide in the second waveguide modulation module. The slow waveguide includes at least one of the following modulation structures: PN junction modulation structure, PIN junction modulation structure, and MOS modulation structure.

5. The electro-optic modulator according to claim 4, characterized in that: When the slow waveguide includes a PN junction modulation structure, the i-th stage slow waveguide in the first waveguide modulation module serves as the first modulation PN junction, and the i-th stage slow waveguide in the second waveguide modulation module serves as the second modulation PN junction; the i-th stage electrical signal is sequentially applied to the first modulation PN junction and the second modulation PN junction.

6. The electro-optic modulator according to claim 5, characterized in that: When the slow waveguide includes a PN junction modulation structure, the i-th stage slow waveguide in the first waveguide modulation module serves as the third modulation PN junction, and the i-th stage slow waveguide in the second waveguide modulation module serves as the fourth modulation PN junction; the i-th stage electrical signal is applied to the third modulation PN junction and the fourth modulation PN junction respectively.

7. The electro-optic modulator according to claim 1, characterized in that: The electrical signal driving module includes m-1 segmented signal delay units and 2m electrical connection parts; Each electrical connection is set up in a one-to-one correspondence with each slow waveguide, used to receive the corresponding electrical signal and modulate the refractive index of the corresponding slow waveguide; Each segmented signal delay unit is connected in series; the input of the first-level segmented signal delay unit receives the first-level electrical signal, delays it, and outputs it at the output; the input of the j-th level segmented signal delay unit receives the electrical signal output from the j-1 level, delays it, and outputs it at the output, where j is an integer greater than 1 and less than or equal to m-1.

8. The electro-optic modulator according to claim 7, characterized in that: The segmented signal delay unit includes a delay section; the delay section includes wires arranged in a sinusoidal waveform; the first end of the wires serves as the input end of the segmented signal delay unit, and the second end serves as the output end of the segmented signal delay unit.

9. The electro-optic modulator according to claim 7, characterized in that: The segmented signal delay unit includes an electrical delay device; the electrical delay device includes a resistor and a capacitor; the first end of the resistor serves as the input end of the segmented signal delay unit, and the second end serves as the output end of the segmented signal delay unit; the first end of the capacitor is connected to the second end of the resistor, and the second end is connected to a reference ground.

10. The electro-optic modulator according to claim 7, characterized in that: The electrical signal driving module further includes m electrical signal power compensation units; each electrical signal power compensation unit is configured to correspond one-to-one with each level of electrical signal and is used to compensate for the power value of each level of electrical signal.

11. The electro-optic modulator according to claim 7, characterized in that: The electrical signal power compensation unit is configured as an electrical amplifier; the input terminal of the electrical amplifier is connected to the corresponding electrical signal, and the output terminal is connected to the corresponding electrical connection parts at each stage.

12. The electro-optic modulator according to any one of claims 7 to 11, characterized in that: The electrical signal driving module further includes a preamplifier and / or a matching unit; the preamplifier receives the input electrical signal and outputs a first-stage electrical signal to increase the strength of the input electrical signal; the first end of the matching unit is connected to the m-th stage electrical signal, and the second end is connected to a reference ground.

13. An electro-optic modulation device, characterized in that: The electro-optic modulation device includes the electro-optic modulator according to any one of claims 1 to 12; wherein the first waveguide modulation module and the second waveguide modulation module are designed on different chips from the electrical signal driving module, or the first waveguide modulation module, the second waveguide modulation module and the electrical signal driving module are designed on the same chip.

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