On-chip integrated electro-optical modulation-optical amplification device

Abstract

According to the on-chip integrated electro-optical modulation-optical amplification device, effective integration of electro-optical modulation and optical amplification is achieved through a simple waveguide structure, the system complexity of a traditional discrete device is greatly reduced, and the packaging and integration size of the device is reduced; by designing a symmetrical optical amplification waveguide structure, dual-channel output of amplified optical signals after modulation is realized; meanwhile, seamless connection of electro-optical modulation and light amplification is achieved, the amplification working efficiency after modulation is greatly improved, and the cascade noise of the system can be restrained; according to the invention, the inherent loss of a modulator and a transmission line in an optical communication system can be compensated through an integrated electro-optical modulation and optical amplification structure, and a technical scheme can be provided for a relay-free long-distance signal transmission system.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated optical chips, and in particular to an on-chip integrated electro-optic modulation - optical amplification device. Background Art

[0002] With the development of optical communication systems towards high speed, high density, and low power consumption, photonic integrated chips (PICs) have become a key means to break through the technical bottlenecks of traditional discrete devices. Among them, electro-optic modulators and waveguide amplifiers are important components in the field of high-speed optical communication. By modulating the phase and amplitude of optical signals and amplifying the intensity, the conversion between high-speed electrical signals and optical signals and the long-distance and stable transmission of optical signals are realized. It is predicted that the global market size of high-speed optical modules will exceed $10 billion in 2025, and the drive for co-design technology of electro-optic modulation - amplification has become a research hotspot.

[0003] The direct amplification of the modulated optical signal can compensate for the inherent loss of the modulator in optical communication, effectively extend the transmission distance of the signal without repeaters and suppress cascaded noise. At the same time, it is expected to be deeply integrated with active or passive devices such as lasers and wavelength division multiplexers, promoting the application of full-functional photonic chips in emerging fields such as autonomous driving LiDAR and on-chip optical neural networks.

[0004] However, most current electro-optic modulators and waveguide amplifiers are discrete components, facing challenges such as increased volume, high insertion loss, high power consumption, and poor compatibility with CMOS processes during device packaging, making it difficult to meet the urgent requirements for device miniaturization and functional integration in emerging fields such as optical interconnection in data centers (400G / 800G), microwave photonics, and quantum computing. Summary of the Invention

[0005] The present invention discloses an on-chip integrated electro-optic modulation - optical amplification device to overcome the above technical problems.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] An on-chip integrated electro-optic modulation - optical amplification device, comprising a lithium niobate substrate, a first input waveguide, a modulation waveguide, a second input waveguide, a third input waveguide, a first transmission waveguide, a second transmission waveguide, a first coupling waveguide, a second coupling waveguide, a first coupling and output waveguide, and a second coupling and output waveguide;

[0008] The first input waveguide, the modulation waveguide, the second input waveguide, the third input waveguide, the first transmission waveguide, the second transmission waveguide, the first coupling waveguide, the second coupling waveguide, the first coupling and output waveguide, and the second coupling and output waveguide are integrally arranged on the top surface of the lithium niobate substrate;

[0009] The first input waveguide is disposed on the input side of the lithium niobate substrate and is used to introduce monochromatic signal light;

[0010] The first input waveguide is connected to the modulation waveguide; the output ends of the modulation waveguide are respectively connected to the first transmission waveguide and the second transmission waveguide;

[0011] The output end of the first transmission waveguide is connected to the input end of the first coupling waveguide; the output end of the second transmission waveguide is connected to the input end of the second coupling waveguide;

[0012] The second input waveguide and the third input waveguide are disposed on both sides of the first input waveguide;

[0013] The output end of the second input waveguide is connected to the input end of the first coupling waveguide; the output end of the third input waveguide is connected to the input end of the second coupling waveguide;

[0014] The output end of the first coupling waveguide is connected to the first coupling and output waveguide; the output end of the second coupling waveguide is connected to the second coupling and output waveguide;

[0015] The first coupling and output waveguide and the second coupling and output waveguide are disposed on the output side of the lithium niobate substrate.

[0016] Further, the modulation waveguide is used to modulate the input monochromatic signal light and includes a Y waveguide, a first straight waveguide, a second straight waveguide, a coupled interference waveguide, and a first electrode, a second electrode, and a third electrode;

[0017] The coupled interference waveguide includes a third straight waveguide and a fourth straight waveguide;

[0018] The input end of the Y waveguide is connected to the output end of the first input waveguide;

[0019] The two output ends of the Y waveguide are respectively connected to the first straight waveguide and the second straight waveguide;

[0020] The output end of the first straight waveguide is connected to the third straight waveguide; the output end of the second straight waveguide is connected to the fourth straight waveguide;

[0021] The output end of the third straight waveguide is connected to the first transmission waveguide; the output end of the fourth straight waveguide is connected to the second transmission waveguide;

[0022] The second electrode is disposed between the first straight waveguide and the second straight waveguide;

[0023] The first electrode is disposed between the second input waveguide and the first straight waveguide; and the distance between the first electrode and the first straight waveguide is less than the distance between the first electrode and the second input waveguide;

[0024] The third electrode is disposed between the second straight waveguide and the third input waveguide, and the distance between the third electrode and the second straight waveguide is less than the distance between the third electrode and the third input waveguide.

[0025] Further, the first coupled waveguide includes a first optical amplification waveguide and a fifth straight waveguide;

[0026] The input end of the first optical amplification waveguide is connected to the output end of the second input waveguide; the input end of the fifth straight waveguide is connected to the output end of the first transmission waveguide;

[0027] The output ends of the first optical amplification waveguide and the fifth straight waveguide are both connected to the first coupled and output waveguide;

[0028] The second coupled waveguide includes a sixth straight waveguide and a second optical amplification waveguide;

[0029] The input end of the sixth straight waveguide is connected to the output end of the second transmission waveguide;

[0030] The input end of the second optical amplification waveguide is connected to the output end of the third input waveguide;

[0031] The output ends of the sixth straight waveguide and the second optical amplification waveguide are both connected to the second coupled and output waveguide.

[0032] Further, both the first optical amplification waveguide and the second optical amplification waveguide are erbium ion-doped waveguides.

[0033] Further, the first coupled and output waveguide includes a first optical amplification and output waveguide and a fourth transmission waveguide. The first optical amplification and output waveguide is connected to the output end of the first optical amplification waveguide through a third optical amplification waveguide; the fourth transmission waveguide is connected to the output end of the fifth straight waveguide through a third transmission waveguide;

[0034] The second coupled and output waveguide includes a second optical amplification and output waveguide and a sixth transmission waveguide. The second optical amplification and output waveguide is connected to the output end of the second optical amplification waveguide through a fourth optical amplification waveguide; the sixth transmission waveguide is connected to the sixth straight waveguide through a fifth transmission waveguide.

[0035] Further, the third optical amplification waveguide, the fourth optical amplification waveguide, the first optical amplification and output waveguide, and the second optical amplification and output waveguide are all erbium ion-doped waveguides.

[0036] Beneficial effects: An on-chip integrated electro-optic modulation - optical amplification device of the present invention realizes the effective integration of electro-optic modulation and optical amplification through a simple waveguide structure, greatly reducing the system complexity of traditional discrete devices and decreasing the size of device packaging and integration; by designing a symmetric optical amplification waveguide structure, dual-channel output of the amplified optical signal after modulation is achieved; at the same time, seamless connection between electro-optic modulation and optical amplification is realized, greatly improving the working efficiency of amplification after modulation and helping to suppress the cascaded noise of the system; the integrated electro-optic modulation and optical amplification structure of the present invention can compensate for the inherent losses of the modulator and transmission line in the optical communication system and can provide a technical solution for a long-distance signal transmission system without repeaters. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 It is a three-dimensional structure schematic diagram of the on-chip integrated electro-optic modulation - optical amplification device of the present invention;

[0039] Figure 2 It is a planar structure schematic diagram of the on-chip integrated electro-optic modulation - optical amplification device in Embodiment 1;

[0040] Figure 3 It is a planar structure schematic diagram of an on-chip integrated electro-optic modulation - optical amplification device in Embodiment 2;

[0041] Figure 4 For Figure 2 It is a schematic diagram of the change of the normalized power of the signal light of A41 and A42 in with voltage;

[0042] Figure 5 For Figure 2 It is a schematic diagram of the change of the normalized power of the signal light of 52, 42, 32 and 22 in with voltage when no pump light is added;

[0043] Figure 6 For Figure 3 It is a schematic diagram of the change of the normalized power of the signal light of 52, 42, 32 and 22 in with voltage when no pump light is added. Detailed Embodiments

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0045] This embodiment introduces an on-chip integrated electro-optic modulation - optical amplification device, as Figures 1-3 shown, including a lithium niobate substrate S, a first input waveguide 1, a modulation waveguide A, a second input waveguide 2, a third input waveguide 3, a first transmission waveguide 4, a second transmission waveguide 5, a first coupling waveguide B1, a second coupling waveguide B2, a first coupling and output waveguide B3, and a second coupling and output waveguide B4;

[0046] The first input waveguide 1, modulation waveguide A, second input waveguide 2, third input waveguide 3, first transmission waveguide 4, second transmission waveguide 5, first coupling waveguide B1, second coupling waveguide B2, first coupling and output waveguide B3, and second coupling and output waveguide B4 are integrally arranged on the top surface of the lithium niobate substrate S;

[0047] Specifically, the electro-optic modulation - optical amplification device of this embodiment is fabricated based on a lithium niobate substrate. After lithography selects the structure, a high-refractive-index optical waveguide structure is formed through titanium diffusion doping technology.

[0048] The first input waveguide 1 is arranged on the input side of the lithium niobate substrate S for introducing monochromatic signal light;

[0049] The first input waveguide 1 is connected to the modulation waveguide A; the output end of the modulation waveguide A is respectively connected to the first transmission waveguide 4 and the second transmission waveguide 5, and both the first transmission waveguide 4 and the second transmission waveguide 5 are used for transmitting monochromatic signal light;

[0050] The output end of the first transmission waveguide 4 is connected to the input end of the first coupling waveguide B1; the output end of the second transmission waveguide 5 is connected to the input end of the second coupling waveguide B2;

[0051] The second input waveguide 2 and the third input waveguide 3 are arranged on both sides of the first input waveguide 1 and are also arranged on the input side of the lithium niobate substrate S;

[0052] The output end of the second input waveguide 2 is connected to the input end of the first coupling waveguide B1; the output end of the third input waveguide 3 is connected to the input end of the second coupling waveguide B2;

[0053] The output end of the first coupling waveguide B1 is connected to the first coupling and output waveguide B3; the output end of the second coupling waveguide B2 is connected to the second coupling and output waveguide B4;

[0054] The first coupling and output waveguide B3 and the second coupling and output waveguide B4 are arranged on the output side of the lithium niobate substrate S.

[0055] Aiming at the problem of the lack of current monolithic integrated multifunctional devices, this embodiment proposes an on-chip integrated electro-optic modulation - optical amplification device. By designing a reasonable optical waveguide structure, it can realize the modulation and direct amplification of optical signals on a single chip, greatly reduce the packaging size of discrete electro-optic modulators and waveguide amplifiers, simplify the complexity of the optical signal amplification system after modulation, reduce the loss of optical signals, and meet the application requirements of optical signal modulation - amplification integrated modules in multiple fields.

[0056] Specifically, in this embodiment, the lithium niobate substrate S forms the first input waveguide 1, modulation waveguide A, second input waveguide 2, third input waveguide 3, first transmission waveguide 4, second transmission waveguide 5, first coupling waveguide B1, second coupling waveguide B2, first coupling and output waveguide B3, and second coupling and output waveguide B4 through a waveguide manufacturing process;

[0057] Preferably, the modulation waveguide A is used to modulate the input monochromatic signal light, and includes a Y waveguide A1, a first straight waveguide A2, a second straight waveguide A3, a coupled interference waveguide A4, and a first electrode E1, a second electrode E2, and a third electrode E3;

[0058] The coupled interference waveguide A4 includes a third straight waveguide A41 and a fourth straight waveguide A42;

[0059] The input end of the Y waveguide A1 is connected to the output end of the first input waveguide 1;

[0060] The two output ends of the Y waveguide A1 are respectively connected to the first straight waveguide A2 and the second straight waveguide A3;

[0061] The output end of the first straight waveguide A2 is connected to the third straight waveguide A41; the output end of the second straight waveguide A3 is connected to the fourth straight waveguide A42;

[0062] The output end of the third straight waveguide A41 is connected to the first transmission waveguide 4; the output end of the fourth straight waveguide A42 is connected to the second transmission waveguide 5;

[0063] The second electrode E2 is arranged between the first straight waveguide A2 and the second straight waveguide A3;

[0064] The first electrode E1 is disposed between the second input waveguide 2 and the first straight waveguide A2; and the distance between the first electrode E1 and the first straight waveguide A2 is less than the distance between the first electrode E1 and the second input waveguide 2; that is, the first electrode E1 is closer to the side where the first straight waveguide A2 is disposed.

[0065] The third electrode E3 is disposed between the second straight waveguide A3 and the third input waveguide 3, and the distance between the third electrode E3 and the second straight waveguide A3 is less than the distance between the third electrode E3 and the third input waveguide 3, that is, the third electrode E3 is closer to the side where the second straight waveguide A3 is disposed.

[0066] Specifically, the Y waveguide A1 of this embodiment includes 1 input end and 2 output ends, and is used for splitting the light beam output by the first input waveguide 1, and equally dividing the input signal light into two beams of light with equal power and the same phase. Subsequently, the two beams of light respectively enter the first straight waveguide A2 and the second straight waveguide A3, and the first straight waveguide A2 and the second straight waveguide A3 are used for transmitting the light beam output by the Y waveguide A1; by applying voltages to the first electrode E1, the second electrode E2, and the third electrode E3, the refractive indices of the first straight waveguide A2 and the second straight waveguide A3 are changed, so that a phase difference is generated in the signal light transmitted by the first straight waveguide A2 and the second straight waveguide A3. Then, the two beams of signal light enter the coupled interference waveguide A4, and are mutually coupled and interfered simultaneously between the third straight waveguide A41 and the fourth straight waveguide A42. After interference, the intensities of the two beams of signal light change, and finally they are respectively output through the first transmission waveguide 4 and the second transmission waveguide 5;

[0067] Preferably, both the second input waveguide 2 and the third input waveguide 3 are used for inputting monochromatic pump light.

[0068] Preferably, the first coupling waveguide B1 includes a first optical amplification waveguide B11 and a fifth straight waveguide B12;

[0069] The input end of the first optical amplification waveguide B11 is connected to the output end of the second input waveguide 2; the input end of the fifth straight waveguide B12 is connected to the output end of the first transmission waveguide 4;

[0070] The output ends of the first optical amplification waveguide B11 and the fifth straight waveguide B12 are both connected to the first coupling and output waveguide B3;

[0071] The second coupling waveguide B2 includes a sixth straight waveguide B21 and a second optical amplification waveguide B22;

[0072] The input end of the sixth straight waveguide B21 is connected to the output end of the second transmission waveguide 5;

[0073] The input end of the second optical amplification waveguide B22 is connected to the output end of the third input waveguide 3;

[0074] The output ends of the sixth straight waveguide B21 and the second optical amplification waveguide B22 are both connected to the second coupling and output waveguide B4.

[0075] The first optical amplification waveguide B11 and the second optical amplification waveguide B22 are both erbium ion-doped waveguides, which are used to transmit monochromatic pump light, amplify the modulated monochromatic signal light, and output the signal light and the pump light.

[0076] Specifically, the pump light introduced into the first optical amplification waveguide B11 and the second optical amplification waveguide B22 excites erbium ions, causing population inversion between the upper and lower energy levels inside the erbium ions. Then, the signal light coupled into the first optical amplification waveguide B11 and the second optical amplification waveguide B22 causes the particles in the upper energy level of the excited erbium ions to undergo stimulated emission transitions, generating laser light identical to the signal light, thereby achieving amplification of the signal light and finally outputting all the signal light and the remaining pump light.

[0077] Specifically, the first coupling waveguide B1 and the second coupling waveguide B2 are both used to couple the monochromatic signal light output from the first transmission waveguide 4 and the second transmission waveguide 5 from the transmission waveguide to the optical amplification waveguide. The modulated signal light enters the first coupling waveguide B1 and the second coupling waveguide B2 through the first transmission waveguide 4 and the second transmission waveguide 5 respectively. Most of the signal light entering the first coupling waveguide B1 is coupled to the first optical amplification waveguide B11 through the fifth straight waveguide B12, and most of the signal light entering the second coupling waveguide B2 is coupled to the second optical amplification waveguide B22 through the sixth straight waveguide B21. After the signal light is coupled and input into the first optical amplification waveguide B11 and the second optical amplification waveguide B22, stimulated amplification begins.

[0078] Preferably, the first coupling and output waveguide B3 includes a first optical amplification and output waveguide 22 and a fourth transmission waveguide 42. The first optical amplification and output waveguide 22 is connected to the output end of the first optical amplification waveguide B11 through a third optical amplification waveguide 21. The fourth transmission waveguide 42 is connected to the output end of the fifth straight waveguide B12 through a third transmission waveguide 41.

[0079] The second coupling and output waveguide B4 includes a second optical amplification and output waveguide 32 and a sixth transmission waveguide 52. The second optical amplification and output waveguide 32 is connected to the output end of the second optical amplification waveguide B22 through a fourth optical amplification waveguide 31. The sixth transmission waveguide 52 is connected to the sixth straight waveguide B21 through a fifth transmission waveguide 51.

[0080] Specifically, in this embodiment, both the third optical amplification waveguide 21 and the first optical amplification and output waveguide 22 are erbium-ion-doped waveguides, capable of continuously amplifying the signals transmitted by the first optical amplification waveguide B11. Both the fourth optical amplification waveguide 31 and the second optical amplification and output waveguide 32 are erbium-ion-doped waveguides, capable of continuously amplifying the signals transmitted by the second optical amplification waveguide B22.

[0081] Specifically, the first coupling and output waveguide B3 and the second coupling and output waveguide B4 are both used to couple the residual monochromatic signal light from the transmission waveguide to the optical amplification waveguide and output all the signal light and the pump light; the signal light introduced by the first optical amplification waveguide B11 is continuously amplified through the first optical amplification waveguide B11, the third optical amplification waveguide 21, and the first optical amplification and output waveguide 22, and the residual signal light output by the fifth straight waveguide B12 enters the first coupling and output waveguide B3 after passing through the third transmission waveguide 41, and then is all coupled into the first optical amplification and output waveguide 22 by the fourth transmission waveguide 42 and also undergoes stimulated amplification, and finally all the signal light and the pump light are output by the first optical amplification and output waveguide 22; the signal light introduced by the second optical amplification waveguide B22 is continuously amplified through the second optical amplification waveguide B22, the fourth optical amplification waveguide 31, and the second optical amplification and output waveguide 32, and the residual signal light output by the sixth straight waveguide B21 enters the coupling and output waveguide B4 after passing through the fifth transmission waveguide 51, and then is all coupled into the second optical amplification and output waveguide 32 by the sixth transmission waveguide 52 and also undergoes stimulated amplification, and finally all the signal light and the pump light are output by the second optical amplification and output waveguide 32.

[0082] Specifically, in this embodiment, the first optical amplification waveguide B11 is used to transmit the pump light, amplify and transmit the signal light; the fifth straight waveguide B12 is used to transmit the signal light; the sixth straight waveguide B21 is used to transmit the signal light; the second optical amplification waveguide B22 is used to transmit the pump light, amplify and transmit the signal light.

[0083] Specifically, in this embodiment, assuming that the optical power input from the first input waveguide 1 is P0 and the optical amplitude input from the first input waveguide 1 is E0, then:

[0084] P0 = E0 2

[0085] Then the optical fields entering the first straight waveguide A2 and the second straight waveguide A3 after being split by the Y waveguide A1 are:

[0086]

[0087] Among them, f is the frequency of the signal light; θ is the initial phase of the optical signal in the first straight waveguide A2 and the second straight waveguide A3, assumed to be 0; E2(f) represents the optical field in the first straight waveguide A2; E3(f) represents the optical field in the second straight waveguide A3; i represents the imaginary unit, satisfying i 2 = -1; then, voltages are applied to the first electrode E1, the second electrode (E2), and the third electrode E3 to cause a phase difference Δφ between the two beams of signal light in the first straight waveguide A2 and the second straight waveguide A3. At this time, the optical fields of the signal light output from the first straight waveguide A2 and the second straight waveguide A3 can be respectively expressed as:

[0088]

[0089] Subsequently, the signal light output from the first straight waveguide A2 and the second straight waveguide A3 is respectively input into the third straight waveguide A41 and the fourth straight waveguide A42 for coupled interference. After mathematical derivation, the signal light powers output from the third straight waveguide A41 and the fourth straight waveguide A42 are respectively expressed as:

[0090]

[0091] Among them, P 01 represents the signal light power output from the third straight waveguide A41; P 02 represents the signal light power output from the fourth straight waveguide A42; P0 represents the optical power input by the first input waveguide 1;

[0092] K is the coupling coefficient of the coupled interference waveguide A4, and L is the coupling length of the coupled interference waveguide A4. After that, the modulated signal light output from the coupled interference waveguide A4 is input into the subsequent coupling and optical amplification waveguide through the first transmission waveguide 4 and the second transmission waveguide 5.

[0093] Secondly, the principle of optical amplification is briefly described as follows: When the signal light is input into the modulator, the pump light is introduced into the optical amplification waveguide to excite the erbium ions in the waveguide, causing population inversion between the upper and lower energy levels inside. Assume that the wavelength of the used pump light is 980 nm, and the electrons in the ground state energy level 4 I 15 / 2 absorb the energy of the pump light and transition to the excited state energy level 4 I 11 / 2 , which is the ground state absorption process; subsequently, the electrons in the excited state energy level 4 I 11 / 2 rapidly undergo non-radiative transitions to the metastable energy level 4 I 13 / 2 , thus achieving the metastable energy level 4 I 13 / 2 and the ground state energy level 4 I 15 / 2Population inversion; when an input signal light is present, the electrons in the metastable energy level 4 I 13 / 2 will undergo stimulated emission transitions to the ground energy level 4 I 15 / 2 and emit laser light that is exactly the same as the signal light, thereby achieving amplification of the signal light.

[0094] When there is and is no pump light input, the signal light powers output by the first optical amplification and output waveguide 22 or the second optical amplification and output waveguide 32 are respectively denoted as P on and P off , then the gain G se of the signal light is expressed as:

[0095]

[0096] The internal net gain of the waveguide amplifier is expressed as:

[0097] G net = G se - α total_loss L1

[0098] α total_loss = α a (λ) + α p (λ)

[0099] where α total_loss is the total loss per unit length of the waveguide, mainly including the erbium ion absorption loss α a (λ) and the waveguide transmission loss α p (λ); L1 is the effective length of the optical amplification waveguide. G net represents the internal net gain of the waveguide amplifier;

[0100] This embodiment seamlessly connects the modulation and amplification of the signal light, effectively realizing the integration and miniaturization of the device and improving the working efficiency.

[0101] In the embodiment of the present invention, an X-cut Z-propagation lithium niobate crystal material is selected, and the waveguide manufacturing process uses titanium diffusion technology, which can also be extended to other manufacturing technologies, such as proton exchange technology, thin film technology, etc.;

[0102] Example 1:

[0103] Such as Figure 1 and Figure 2As shown in the figure, this embodiment provides a structural diagram of an on-chip integrated electro-optic modulation - optical amplification device, which includes a lithium niobate substrate S, a first input waveguide 1, a modulation waveguide A, a second input waveguide 2, a third input waveguide 3, a first transmission waveguide 4, a second transmission waveguide 5, a first coupling waveguide B1, a second coupling waveguide B2, a first coupling and output waveguide B3, and a second coupling and output waveguide B4; the signal light introduced by the first input waveguide 1 is modulated by the modulation waveguide A, and the modulated signal light is input into the symmetrically arranged first optical amplification waveguide B11, third optical amplification waveguide 21, first optical amplification and output waveguide 22, second optical amplification waveguide B22, fourth optical amplification waveguide 31, and second optical amplification and output waveguide 32 on both sides through the first transmission waveguide 4, second transmission waveguide 5, first coupling waveguide B1, second coupling waveguide B2, first coupling and output waveguide B3, and second coupling and output waveguide B4. Subsequently, the signal light is continuously amplified in the optical amplification waveguide and finally output through the first optical amplification and output waveguide 22 and the second optical amplification and output waveguide 32.

[0104] In this embodiment, the width and thickness of the waveguide are determined by the effective refractive index method, and the waveguide transmission should meet the requirements of low-loss transmission.

[0105] In this embodiment, the second input waveguide 2 and the third input waveguide 3, the first transmission waveguide 4 and the second transmission waveguide 5, the first coupling waveguide B1 and the second coupling waveguide B2, and the first coupling and output waveguide B3 and the second coupling and output waveguide B4 are respectively waveguides with the same structure and process, and the inherent phase difference between them is 0. In the modulation waveguide A, the first straight waveguide A2 and the second straight waveguide A3, and the third straight waveguide A41 and the fourth straight waveguide A42 are respectively waveguides with the same structure and process, and the inherent phase difference between them is 0.

[0106] As Figure 4 shown, in this embodiment, the variation of the normalized power of the signal light output by the third straight waveguide A41 and the fourth straight waveguide A42 with voltage satisfies the periodic variation of trigonometric functions and the phase difference is π; when appropriate voltages are applied to the first electrode E1, second electrode E2, and third electrode E3 in the modulation waveguide A, the refractive indices in the first straight waveguide A2 and the second straight waveguide A3 will change, a phase difference Δφ will be generated between the two beams of signal light output by the first straight waveguide A2 and the second straight waveguide A3, and the signal light will be introduced into the coupled interference waveguide A4, and then the intensity coupling and interference will occur in the third straight waveguide A41 and the fourth straight waveguide A42.

[0107] As Figure 5As shown, in this embodiment, when no pump light is introduced into the second input waveguide 2 and the third input waveguide 3, the variation of the normalized power of the signal light output from the first optical amplification and output waveguide 22 and the second optical amplification and output waveguide 32 with voltage satisfies trigonometric periodic variation and a phase difference of π; the modulated signal light transmitted by the first transmission waveguide 4 and the second transmission waveguide 5 passes through the first coupling waveguide B1, the second coupling waveguide B2, the first coupling and output waveguide B3, and the second coupling and output waveguide B4, and finally all the amplified signal light is output by the first optical amplification and output waveguide 22 and the second optical amplification and output waveguide 32. There is basically no signal light output from the fourth transmission waveguide 42 and the sixth transmission waveguide 52, that is, except for the part of the modulated signal light that is absorbed and transmitted with loss, the remaining part all undergoes the process of waveguide optical amplification; the gain of optical amplification can be controlled by adjusting the effective length of the optical amplification waveguide.

[0108] Embodiment 2:

[0109] As Figure 3 shown, this embodiment provides a structural diagram of an on-chip integrated electro-optic modulation-optical amplification device, including a lithium niobate substrate S, a first input waveguide 1, a modulation waveguide A, a second input waveguide 2, a third input waveguide 3, a first transmission waveguide 4, a second transmission waveguide 5, a first coupling waveguide B1, and a second coupling waveguide B2; the signal light introduced by the first input waveguide 1 is modulated by the modulation waveguide A, and the modulated signal light is respectively input into the first coupling waveguide B1 and the second coupling waveguide B2 through the first transmission waveguide 4 and the second transmission waveguide 5; a part of the signal light input into the first coupling waveguide B1 is coupled into the first optical amplification waveguide B11, and the remaining part is in the fifth straight waveguide B12. The signal light introduced by the first optical amplification waveguide B11 is continuously amplified by the first optical amplification waveguide B11, the third optical amplification waveguide 21, and the first optical amplification and output waveguide 22, and finally output by the first optical amplification and output waveguide 22. The remaining signal light in the fifth straight waveguide B12 is output through the third transmission waveguide 41 and the fourth transmission waveguide 42; a part of the signal light input into the second coupling waveguide B2 enters the second optical amplification waveguide B22, and the remaining part is in the sixth straight waveguide B21. The signal light introduced by the second optical amplification waveguide B22 is continuously amplified by the second optical amplification waveguide B22, the fourth optical amplification waveguide 31, and the second optical amplification and output waveguide 32, and finally output by the second optical amplification and output waveguide 32. The remaining signal light in the sixth straight waveguide B21 is output after passing through the fifth transmission waveguide 51 and the sixth transmission waveguide 52;

[0110] In this embodiment, the width and thickness of the waveguide can also be determined according to the effective refractive index method, and the waveguide transmission should meet the requirements of low-loss transmission;

[0111] In this embodiment, considering the errors introduced by the manufacturing process, in the same processing flow, the second input waveguide 2 and the third input waveguide 3, the first transmission waveguide 4 and the second transmission waveguide 5, and the first coupling waveguide B1 and the second coupling waveguide B2 are respectively waveguides with nearly the same structure and process, and the inherent phase difference between them is 0. At the same time, in the modulation waveguide A, the first straight waveguide A2 and the second straight waveguide A3, and the third straight waveguide A41 and the fourth straight waveguide A42 are respectively waveguides with nearly the same structure and process, and the inherent phase difference between them is 0;

[0112] In this embodiment, the signal light output from the modulation waveguide A to the first transmission waveguide 4 and the second transmission waveguide 5 still satisfies Figure 4 the periodic law shown, that is, the change of the normalized optical power with voltage satisfies the periodic change of trigonometric functions, and the phase difference is π;

[0113] In this embodiment, the modulated signal light is respectively input into the first coupling waveguide B1 and the second coupling waveguide B2 through the first transmission waveguide 4 and the second transmission waveguide 5. Among them, both the first coupling waveguide B1 and the second coupling waveguide B2 are 3dB couplers. At this time, the signal optical powers output from the first coupling waveguide B1 to the third optical amplification waveguide 21 and the third transmission waveguide 41 are approximately equal, and the signal optical powers output from the second coupling waveguide B2 to the fifth transmission waveguide 51 and the fourth optical amplification waveguide 31 are approximately equal; the signal light transmitted through the first optical amplification waveguide B11, the third optical amplification waveguide 21, and the first optical amplification and output waveguide 22 is continuously amplified and finally output by the first optical amplification and output waveguide 22. The remaining signal light in the fifth straight waveguide B12 is output through the third transmission waveguide 41 and the fourth transmission waveguide 42; the signal light transmitted through the second optical amplification waveguide B22, the fourth optical amplification waveguide 31, and the second optical amplification and output waveguide 32 is also continuously amplified and finally output by the second optical amplification and output waveguide 32. The remaining signal light in the sixth straight waveguide is output through the fifth transmission waveguide 51 and the sixth transmission waveguide 52;

[0114] As Figure 6 shown, in this embodiment, when no pump light is introduced into the second input waveguide 2 and the third input waveguide 3, the normalized optical powers of the signal light output from the first optical amplification and output waveguide 22 and the fourth transmission waveguide 42, and the sixth transmission waveguide 52 and the second optical amplification and output waveguide 32 should be equal respectively. The changes of the normalized optical powers of the two pairs of output signal lights with voltage satisfy the periodic change of trigonometric functions, and the phase difference is π. That is, nearly half of the signal light after modulation realizes optical amplification and is output through the symmetric double-waveguide channels, and the other half of the optical power is directly output. The subsequent detection circuit can directly measure the information of the original applied electric field, which can meet the requirements of optical signal detection and transmission in multiple scenarios.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An on-chip integrated electro-optic modulation - optical amplification device, characterized in that, It includes a lithium niobate substrate (S), a first input waveguide (1), a modulation waveguide (A), a second input waveguide (2), a third input waveguide (3), a first transmission waveguide (4), a second transmission waveguide (5), a first coupling waveguide (B1), a second coupling waveguide (B2), a first coupling and output waveguide (B3), and a second coupling and output waveguide (B4); The first input waveguide (1), modulation waveguide (A), second input waveguide (2), third input waveguide (3), first transmission waveguide (4), second transmission waveguide (5), first coupling waveguide (B1), second coupling waveguide (B2), first coupling and output waveguide (B3), and second coupling and output waveguide (B4) are integrally arranged on the top surface of the lithium niobate substrate (S); The first input waveguide (1) is arranged on the input side of the lithium niobate substrate (S) and is used to introduce monochromatic signal light; The first input waveguide (1) is connected to the modulation waveguide (A); the output ends of the modulation waveguide (A) are respectively connected to the first transmission waveguide (4) and the second transmission waveguide (5); The output end of the first transmission waveguide (4) is connected to the input end of the first coupling waveguide (B1); the output end of the second transmission waveguide (5) is connected to the input end of the second coupling waveguide (B2); The second input waveguide (2) and the third input waveguide (3) are arranged on both sides of the first input waveguide (1); The output end of the second input waveguide (2) is connected to the input end of the first coupling waveguide (B1); the output end of the third input waveguide (3) is connected to the input end of the second coupling waveguide (B2); The output end of the first coupling waveguide (B1) is connected to the first coupling and output waveguide (B3); the output end of the second coupling waveguide (B2) is connected to the second coupling and output waveguide (B4); The first coupling and output waveguide (B3) and the second coupling and output waveguide (B4) are arranged on the output side of the lithium niobate substrate (S).

2. The on-chip integrated electro-optic modulation - optical amplification device according to claim 1, characterized in that, The modulation waveguide (A) is used to modulate the input monochromatic signal light and includes a Y waveguide (A1), a first straight waveguide (A2), a second straight waveguide (A3), a coupled interference waveguide (A4), and a first electrode (E1), a second electrode (E2), and a third electrode (E3); The coupled interference waveguide (A4) includes a third straight waveguide (A41) and a fourth straight waveguide (A42); The input end of the Y waveguide (A1) is connected to the output end of the first input waveguide (1); The two output ends of the Y waveguide (A1) are respectively connected to the first straight waveguide (A2) and the second straight waveguide (A3); The output end of the first straight waveguide (A2) is connected to the third straight waveguide (A41); the output end of the second straight waveguide (A3) is connected to the fourth straight waveguide (A42); The output end of the third straight waveguide (A41) is connected to the first transmission waveguide (4); the output end of the fourth straight waveguide (A42) is connected to the second transmission waveguide (5); The second electrode (E2) is arranged between the first straight waveguide (A2) and the second straight waveguide (A3); The first electrode (E1) is disposed between the second input waveguide (2) and the first straight waveguide (A2); and the distance between the first electrode (E1) and the first straight waveguide (A2) is less than the distance between the first electrode (E1) and the second input waveguide (2). The third electrode (E3) is disposed between the second straight waveguide (A3) and the third input waveguide (3), and the distance between the third electrode (E3) and the second straight waveguide (A3) is less than the distance between the third electrode (E3) and the third input waveguide (3).

3. The on-chip integrated electro-optic modulation - optical amplification device according to claim 1, characterized in that The first coupled waveguide (B1) includes a first optical amplification waveguide (B11) and a fifth straight waveguide (B12). The input end of the first optical amplification waveguide (B11) is connected to the output end of the second input waveguide (2); the input end of the fifth straight waveguide (B12) is connected to the output end of the first transmission waveguide (4). The output ends of the first optical amplification waveguide (B11) and the fifth straight waveguide (B12) are both connected to the first coupled and output waveguide (B3). The second coupled waveguide (B2) includes a sixth straight waveguide (B21) and a second optical amplification waveguide (B22). The input end of the sixth straight waveguide (B21) is connected to the output end of the second transmission waveguide (5). The input end of the second optical amplification waveguide (B22) is connected to the output end of the third input waveguide (3). The output ends of the sixth straight waveguide (B21) and the second optical amplification waveguide (B22) are both connected to the second coupled and output waveguide (B4).

4. The on-chip integrated electro-optic modulation - optical amplification device according to claim 3, wherein, Both the first optical amplification waveguide (B11) and the second optical amplification waveguide (B22) are erbium ion-doped waveguides.

5. The on-chip integrated electro-optic modulation - optical amplification device according to claim 1, characterized in that, The first coupled and output waveguide (B3) includes a first optical amplification and output waveguide (22) and a fourth transmission waveguide (42). The first optical amplification and output waveguide (22) is connected to the output end of the first optical amplification waveguide (B11) through a third optical amplification waveguide (21); the fourth transmission waveguide (42) is connected to the output end of the fifth straight waveguide (B12) through a third transmission waveguide (41). The second coupled and output waveguide (B4) includes a second optical amplification and output waveguide (32) and a sixth transmission waveguide (52). The second optical amplification and output waveguide (32) is connected to the output end of the second optical amplification waveguide (B22) through a fourth optical amplification waveguide (31); the sixth transmission waveguide (52) is connected to the sixth straight waveguide (B21) through a fifth transmission waveguide (51).

6. The integrated electro-optic modulation - optical amplification device on a chip according to claim 5, characterized in that The third optical amplification waveguide (21), the fourth optical amplification waveguide (31), the first optical amplification and output waveguide (22), and the second optical amplification and output waveguide (32) are all erbium ion-doped waveguides.

Images