Optical module and optical modulator

Abstract

The embodiment of the invention provides an optical module and an optical modulator. A hybrid integrated optical chip comprises the optical modulator, a wave separator and a wave combiner. The optical modulator comprises a silicon waveguide layer, an N-type InP layer, a quantum well layer and a P-type InP layer from bottom to top. The gradual change structures are formed at the two ends of the optical modulator respectively, and the silicon waveguide and the InP region waveguide at the same end have opposite gradual change trends, so that mode mutation when light is coupled between the silicon waveguide and the InP waveguide is reduced, and low-loss coupling of the light between the silicon waveguide and the InP waveguide is achieved. In a coupling region at one end of the light modulator, the width of the silicon waveguide is gradually narrowed, and the width of each layer of waveguide in the InP region is gradually widened, so that more light field energy to be modulated is upwards coupled to the InP region for modulation. And in a coupling region at the other end of the optical modulator, the width of the silicon waveguide is gradually increased, and the width of each layer of waveguide in the InP region is gradually reduced, so that more modulation light field energy is downwards coupled into the silicon ridge waveguide to be output.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technology, and in particular to an optical module and an optical modulator. Background Art

[0002] With the development of new services and applications such as cloud computing, mobile internet, and video, advances in optical communication technology are becoming increasingly important. As a key component in optical communication equipment, optical modules enable photoelectric signal conversion. As optical communication technology evolves, the data transmission rate of these modules continues to increase. Summary of the Invention

[0003] The embodiments of the present disclosure provide an optical module and an optical modulator to improve optical coupling efficiency.

[0004] In a first aspect, an optical module provided by an embodiment of the present disclosure includes:

[0005] circuit boards;

[0006] A hybrid integrated optical chip, electrically connected to a circuit board, includes:

[0007] optical modulators;

[0008] A wave splitter is provided on one side of the optical modulator and is used to output two paths of modulated light to the optical modulator respectively;

[0009] A combiner is provided on the other side of the optical modulator and is used to combine the two optical modulated signals generated by the optical modulator;

[0010] The optical modulator comprises, from bottom to top:

[0011] The silicon waveguide layer has a silicon contraction region corresponding to receiving two paths of modulated light on one end facing the splitter, and a silicon expansion region corresponding to coupling two paths of optical modulated signals on the other end facing the combiner.

[0012] The N-type InP layer has a first InP expansion region corresponding to coupling two paths of light to be modulated formed on one end facing the splitter, and a first InP contraction region corresponding to coupling two paths of light modulation signals formed on one end facing the combiner;

[0013] The quantum well layer has a second InP expansion region corresponding to coupling two paths of light to be modulated formed on one end facing the splitter, and a second InP contraction region corresponding to coupling two paths of light modulation signals formed on one end facing the combiner;

[0014] The P-type InP layer has a third InP expansion region corresponding to coupling two paths of light to be modulated formed on one end facing the splitter, and a third InP contraction region corresponding to coupling two paths of light modulation signals formed on one end facing the combiner;

[0015] The silicon contraction region, the first InP expansion region, the second InP expansion region, and the third InP expansion region corresponding to a path of light to be modulated are stacked vertically in sequence, so as to couple the light to be modulated in the silicon contraction region upward to the quantum well layer for signal modulation;

[0016] The silicon expansion region, the first InP contraction region, the second InP contraction region, and the third InP contraction region corresponding to one optical modulation signal are stacked vertically in sequence to couple the optical modulation signal generated by the quantum well layer modulation downward to the silicon expansion region for output.

[0017] In a second aspect, an optical modulator provided by an embodiment of the present disclosure includes:

[0018] The silicon waveguide layer has a silicon contraction region at one end for receiving two paths of light to be modulated, and a silicon expansion region at the other end for coupling two paths of light modulation signals;

[0019] An N-type InP layer, wherein a first InP expansion region corresponding to coupling two paths of light to be modulated is formed at one end, and a first InP contraction region corresponding to coupling two paths of light modulation signals is formed at the other end;

[0020] The quantum well layer has a second InP expansion region corresponding to the coupling of two paths of light to be modulated formed at one end, and a second InP contraction region corresponding to the coupling of two paths of light modulation signals formed at the other end;

[0021] A P-type InP layer, one end of which is respectively formed with a third InP expansion region corresponding to coupling two paths of light to be modulated, and the other end of which is respectively formed with a third InP contraction region corresponding to coupling two paths of light modulation signals;

[0022] The silicon contraction region, the first InP expansion region, the second InP expansion region, and the third InP expansion region corresponding to a path of light to be modulated are stacked vertically in sequence, so as to couple the light to be modulated in the silicon contraction region upward to the quantum well layer for signal modulation;

[0023] The silicon expansion region, the first InP contraction region, the second InP contraction region, and the third InP contraction region corresponding to one optical modulation signal are stacked vertically in sequence to couple the optical modulation signal generated by the quantum well layer modulation downward to the silicon expansion region for output.

[0024] The optical module and optical modulator provided in the embodiments of the present disclosure include a hybrid integrated optical chip. The hybrid integrated optical chip includes an optical modulator, a splitter located on one side of the optical modulator, and a combiner located on the other side of the optical modulator. The optical modulator includes, from bottom to top, a silicon waveguide layer, an N-type InP layer, a quantum well layer, and a P-type InP layer. It can be seen that the optical modulator is an InP / Si hybrid integrated optical modulator. The waveguide layer is based on silicon, which can fully utilize the advantage of low silicon transmission loss; the modulation area is based on InP, which can fully utilize the advantage of high modulation efficiency of InP semiconductor materials. The optical field modes of the silicon waveguide and the InP waveguide are different, so there will be mode field mismatch when light is coupled between the silicon waveguide and the InP waveguide, thereby reducing the optical coupling efficiency. In order to improve the coupling efficiency of light between the silicon waveguide and the InP waveguide, a gradient structure is formed on the end of the optical modulator facing the splitter, and a gradient structure is also formed on the end facing the combiner. The silicon waveguide layer has silicon contraction regions corresponding to the reception of the two paths of light to be modulated formed on one end facing the splitter, and silicon expansion regions corresponding to the coupling of the two light modulation signals formed on one end facing the combiner. The N-type InP layer has first InP expansion regions corresponding to the coupling of the two paths of light to be modulated formed on one end facing the splitter, and first InP contraction regions corresponding to the coupling of the two light modulation signals formed on one end facing the combiner. The quantum well layer has second InP expansion regions corresponding to the coupling of the two paths of light to be modulated formed on one end facing the splitter, and second InP contraction regions corresponding to the coupling of the two light modulation signals formed on one end facing the combiner. The P-type InP layer has third InP expansion regions corresponding to the coupling of the two paths of light to be modulated formed on one end facing the splitter, and third InP contraction regions corresponding to the coupling of the two light modulation signals formed on one end facing the combiner. In the direction from the splitter to the combiner, the waveguide width of the silicon contraction region gradually narrows, while the waveguide widths of the first InP expansion region, the second InP expansion region, and the third InP expansion region gradually widen, respectively, so that one path of light to be modulated is coupled to the corresponding silicon contraction region, and then coupled upward from the silicon contraction region to the first InP expansion region in the corresponding N-type InP layer and the second InP expansion region of the quantum well layer, and then signal modulation is performed within the quantum well layer; wherein the generated optical modulated signal is laterally coupled to the second InP contraction region. In the direction from the splitter to the combiner, the waveguide width of the silicon expansion region gradually widens, while the waveguide widths of the first InP contraction region, the second InP contraction region, and the third InP contraction region gradually narrow, respectively, so that one path of light modulated signal is coupled downward from the second InP contraction region to the first InP contraction region in the N-type InP layer and the silicon expansion region of the silicon waveguide layer, and then output along the silicon expansion region.

[0025] In the present disclosure, gradient structures are formed at both ends of the optical modulator, and the silicon waveguide and the InP region waveguide at the same end present opposite gradient trends, so as to reduce the mode mutation when the light is coupled between the silicon waveguide and the InP waveguide, and realize low-loss coupling of light between the silicon waveguide and the InP waveguide. In the coupling region at one end of the optical modulator, the width of the silicon waveguide gradually narrows, and the width of each layer of waveguide in the InP region gradually widens, so as to squeeze the light field energy in the silicon ridge waveguide into the InP region waveguide, and more light field energy to be modulated is coupled upward to the InP region for modulation. In the coupling region at the other end of the optical modulator, the width of the silicon waveguide gradually widens, and the width of each layer of waveguide in the InP region gradually narrows, so as to squeeze the light field energy of the InP region waveguide into the silicon ridge waveguide, and more modulated light field energy is coupled downward to the silicon ridge waveguide for output. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solutions of the present disclosure, the following briefly describes the drawings used in some embodiments of the present disclosure. Obviously, the drawings described below are merely illustrations of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below are schematic diagrams and are not intended to limit the actual dimensions of the products, actual processes of the methods, actual timing of signals, and the like involved in the embodiments of the present disclosure.

[0027] Figure 1 A partial architecture diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0028] Figure 2 A partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0029] Figure 3 A structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0030] Figure 4 An exploded view of an optical module provided according to some embodiments of the present disclosure;

[0031] Figure 5 A schematic diagram of the internal structure of an optical module provided according to some embodiments of the present disclosure;

[0032] Figure 6 A schematic diagram of the internal structure of an optical chip provided according to some embodiments of the present disclosure;

[0033] Figure 7 A top view structure of an optical modulator provided according to some embodiments of the present disclosure Figure 1 ;

[0034] Figure 8A structural diagram of a silicon waveguide provided according to some embodiments of the present disclosure;

[0035] Figure 9 A three-dimensional structural diagram of an optical modulator provided according to some embodiments of the present disclosure;

[0036] Figure 10 is a cross-sectional structural diagram of an optical modulator provided according to some embodiments of the present disclosure;

[0037] Figure 11 A top view structure of an optical modulator provided according to some embodiments of the present disclosure Figure 2 ;

[0038] Figure 12 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 1 ;

[0039] Figure 13 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 2 ;

[0040] Figure 14 A schematic diagram of an optical path of an optical modulator provided according to some embodiments of the present disclosure;

[0041] Figure 15 A schematic diagram of a gradual change of a silicon waveguide provided according to some embodiments of the present disclosure;

[0042] Figure 16 A structural diagram of an N-type InP layer provided according to some embodiments of the present disclosure;

[0043] Figure 17 A structural diagram of a quantum well layer provided according to some embodiments of the present disclosure;

[0044] Figure 18 A structural diagram of a P-type InP layer provided according to some embodiments of the present disclosure;

[0045] Figure 19 A schematic diagram of the structure of a modulator integrated within an optical chip according to some embodiments of the present disclosure;

[0046] Figure 20 A schematic diagram of a cross-sectional structure of a laser provided according to some embodiments of the present disclosure;

[0047] Figure 21 A partial schematic diagram of a laser provided according to some embodiments of the present disclosure;

[0048] Figure 22 This is a schematic structural diagram of a heater integrated inside an optical modulator according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0049] Some embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, the embodiments described are only some of the embodiments of the present disclosure, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments provided in the present disclosure are within the scope of protection of the present disclosure.

[0050] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as open and inclusive, that is, "including, but not limited to"; the terms "first" and "second" are not to be understood as indicating or implying relative importance or indicating an upper limit on quantity; the term "plurality" means two or more; the term "connected" is to be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, or an integral connection, and can be directly connected or indirectly connected through an intermediate medium; the use of the terms "suitable for" or "configured to" means open and inclusive language, which does not exclude equipment that is suitable for or configured to perform additional tasks or steps; terms such as "parallel", "perpendicular", "same", "consistent", "level" and so on are not limited to absolute mathematical theoretical relationships, but also include acceptable error ranges generated in practice, and also include differences based on the same design concept but due to manufacturing reasons.

[0051] In optical communication technology, to establish information transmission between information processing devices, it is necessary to load the information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When transmitting optical signals within information transmission equipment, they can reduce optical power loss, thereby enabling high-speed, long-distance, and low-cost information transmission. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment typically includes optical network units (ONUs), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment typically includes optical fibers and optical waveguides.

[0052] Optical modules can convert optical signals into electrical signals between information processing devices and information transmission devices. For example, at least one of the optical signal input or output ends of an optical module is connected to an optical fiber, and at least one of the electrical signal input or output ends of the optical module is connected to an optical network terminal. A first optical signal from the optical fiber is transmitted to the optical module, which converts the first optical signal into a first electrical signal and transmits the first electrical signal to the optical network terminal. A second electrical signal from the optical network terminal is transmitted to the optical module, which converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber. Because multiple information processing devices can transmit information via electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, rather than all of them. Here, the information processing device directly connected to the optical module is referred to as the optical module's host computer. Furthermore, the optical signal input or output end of the optical module can be referred to as an optical port, and the electrical signal input or output end of the optical module can be referred to as an electrical port.

[0053] Figure 1 FIG. 1 is a partial structural diagram of an optical communication system according to some embodiments. Figure 1 As shown, the optical communication system mainly includes a remote information processing device 1000 , a local information processing device 2000 , a host computer 100 , an optical module 200 , an optical fiber 101 and a network cable 103 .

[0054] One end of optical fiber 101 extends toward remote information processing device 1000, and the other end of optical fiber 101 is connected to optical module 200 through the optical port of optical module 200. Optical signals can be totally reflected in optical fiber 101, and the propagation of the optical signal in the direction of total reflection can almost maintain the original optical power. The optical signal undergoes multiple total reflections in optical fiber 101 to transmit the optical signal from remote information processing device 1000 to optical module 200, and vice versa, thereby achieving long-distance, low-power information transmission.

[0055] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 may be detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide data signals to the optical module 200, receive data signals from the optical module 200, or monitor or control the operating status of the optical module 200.

[0056] The host computer 100 includes a substantially rectangular housing and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and the optical module 200.

[0057] The host computer 100 also includes an external electrical interface that can access an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104. The network cable interface 104 is configured to access a network cable 103 so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100, so that an electrical signal connection is established between the local information processing device 2000 and the host computer 100 via the network cable 103. For example, a third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 via the network cable 103. The host computer 100 generates a second electrical signal based on the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200. The optical module 200 converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber 101. The second optical signal is then transmitted to the remote information processing device 1000 via the optical fiber 101. For example, a first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101. The first optical signal from the optical fiber 101 is transmitted to the optical module 200. The optical module 200 converts the first optical signal into a first electrical signal. The optical module 200 transmits the first electrical signal to the host computer 100. The host computer 100 generates a fourth electrical signal based on the first electrical signal and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that optical modules are tools for converting optical signals into electrical signals. During this conversion process, the information does not change, but the encoding and decoding methods of the information can change.

[0058] In addition to the optical network terminal, the host computer 100 also includes an optical line terminal (OLT), an optical network device (ONT), or a data center server.

[0059] Figure 2 FIG1 is a partial structural diagram of a host computer according to some embodiments. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. Figure 2 As shown, the host computer 100 further includes a PCB 105 disposed within the housing, a cage 106 disposed on the surface of the PCB 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed within the cage 106. The electrical connector is configured to connect to the electrical port of the optical module 200; the heat sink 107 has protruding structures such as fins to increase the heat dissipation area.

[0060] The optical module 200 is inserted into the cage 106 of the host computer 100. The cage 106 secures the optical module 200. Heat generated by the optical module 200 is transferred to the cage 106 and then dissipated through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 connects with the electrical connector inside the cage 106, thereby establishing a bidirectional electrical signal connection between the optical module 200 and the host computer 100. Furthermore, the optical port of the optical module 200 connects to the optical fiber 101, thereby establishing a bidirectional optical signal connection between the optical module 200 and the optical fiber 101.

[0061] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure, Figure 4 FIG1 is an exploded view of an optical module provided according to some embodiments of the present disclosure. Figure 3 and Figure 4 As shown, the optical module 200 includes a housing, a circuit board 300 disposed within the housing, an optical chip 400, and a light source 500. Exemplarily, the optical chip 400 and the light source 500 are electrically connected to the circuit board 300, and the light output end of the light source 500 is optically coupled to the optical chip 400. In some embodiments, the light output end of the light source 500 is coupled to the optical chip 400 via an optical fiber.

[0062] The housing includes an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square.

[0063] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicular to the base plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0064] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicularly to the base plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and arranged perpendicularly to the cover plate 2011. The two upper side plates are combined with the two lower side plates 2022 to achieve the upper shell 201 covering the lower shell 202.

[0065] The direction of the line connecting the two openings 204 and 205 may be consistent with the length direction of the optical module 200, or may be inconsistent with the length direction of the optical module 200. For example, the opening 204 is located at the end of the optical module 200 ( Figure 3 The opening 205 is also located at the end of the optical module 200 ( Figure 3 Alternatively, opening 204 is located at the end of optical module 200, while opening 205 is located on the side of optical module 200. Opening 204 is an electrical port, through which the gold finger 301 of circuit board 300 extends and is inserted into the electrical connector of host computer 100. Opening 205 is an optical port, configured to receive an external optical fiber 101, thereby connecting optical fiber 101 to optical chip 400 in optical module 200.

[0066] The combined assembly of upper and lower housings 201 and 202 facilitates the installation of the circuit board 300, optical modulation chip, and light source within the housing. These components are encapsulated and protected by the upper and lower housings 201 and 202. Furthermore, during assembly of the circuit board 300, optical chip 400, and light source, positioning components, heat dissipation components, and electromagnetic shielding components are easily positioned, facilitating automated production.

[0067] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0068] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to achieve a fixed connection between the optical module 200 and the host computer, or to release the fixed connection between the optical module 200 and the host computer.

[0069] For example, the unlocking component 600 is located on the outside of the two lower side panels 2022 of the lower housing 202 and includes a snap-fit ​​component that mates with the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the snap-fit ​​component of the unlocking component 600 secures the optical module 200 in the cage 106. When the unlocking component 600 is pulled, the snap-fit ​​component of the unlocking component 600 moves accordingly, thereby changing the connection between the snap-fit ​​component and the host computer, thereby releasing the optical module 200 from the cage 106 and allowing the optical module 200 to be removed from the cage 106.

[0070] The circuit board 300 includes circuit traces, electronic components, and chips. The electronic components and chips are connected according to the circuit design through the circuit traces to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers (LAs), clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0071] The circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also realize the load-bearing function. For example, the rigid circuit board can stably carry the above-mentioned electronic components and chips; the rigid circuit board can also be inserted into the electrical connector in the cage 106 of the host computer 100.

[0072] The circuit board 300 further includes a gold finger 301 formed on the end surface thereof. The gold finger 301 is composed of a plurality of independent pins. The circuit board 300 is inserted into the cage 106, and the gold finger 301 is connected to the electrical connector in the cage 106. The gold finger 301 can be provided on only one side of the circuit board 300 (e.g. Figure 4 The top surface shown in FIG300 can also be located on the upper and lower surfaces of the circuit board 300 to provide a greater number of pins, thus adapting to applications requiring a large number of pins. Gold fingers 301 are configured to establish an electrical connection with a host computer to facilitate power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, and more. Of course, some optical modules also use flexible circuit boards. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement them.

[0073] Figure 5 Schematic diagram of the internal structure of an optical module provided according to some embodiments of the present disclosure. Figure 5 As shown, in some embodiments, the optical chip 400 is used to modulate and demodulate optical signals: the optical chip 400 modulates the received electrical signal into an optical signal, and the optical chip 400 demodulates the received optical signal into an electrical signal.

[0074] In some embodiments, the optical chip 400 may be a monolithically integrated optical chip. Monolithic integration refers to directly epitaxially growing optical device materials on a single substrate to prepare an optical device with intended functions.

[0075] For example, the monolithic integrated optical chip can be a silicon photonic chip. Silicon is easily etched, allowing for the integration of functional devices within the silicon photonic chip, resulting in good integration. For example, a beam splitter, combiner, mixer, photodetector, and other components can be integrated within the silicon photonic chip. As an indirect bandgap semiconductor material, silicon does not exhibit a linear electro-optic effect, only a weak second-order electro-optic effect, resulting in a low modulation rate for the silicon photonic chip.

[0076] For example, a monolithic integrated optical chip can be a thin-film lithium niobate chip. Thin-film lithium niobate exhibits a linear electro-optic effect. An applied electric field causes a linear change in its refractive index in the corresponding direction, allowing light waves transmitted through the medium to have controllable intensity, phase, and other information. Therefore, thin-film lithium niobate can be used as the material for optical modulators, enabling, for example, high modulation rates. Thin-film lithium niobate is relatively hard and difficult to etch, making it difficult to integrate multiple functional devices on its surface. Furthermore, thin-film lithium niobate chips exhibit low optical loss.

[0077] In some embodiments, optical chip 400 may be a hybrid integrated optical chip. Hybrid integration involves fabricating optical components on different substrates based on the strengths of their respective material systems and manufacturing process characteristics, and then integrating them together. The advantage of hybrid integration is that it can fully leverage the excellent performance of different material systems.

[0078] For example, the hybrid integrated optical chip can be a III-V / Si hybrid integrated optical chip. In the III-V / Si hybrid integrated optical chip, the growth material system of the optical modulator is a III-V semiconductor material. III-V is a direct bandgap semiconductor material with a strong quantum well-confined Stark effect. By controlling the change of the external electric field, the carrier changes and thus the refractive index change are caused to achieve optical signal modulation. The growth material system of the optical splitter, optical combiner, mixer, optical detector, etc. is a Si-based material. In some embodiments, the III-V / Si hybrid integrated optical chip can be an InP / Si hybrid integrated optical chip.

[0079] For example, the hybrid integrated optical chip may be a thin-film lithium niobate / Si hybrid integrated optical chip. Compared to a III-V group / Si hybrid integrated optical chip, the optical modulator in the thin-film lithium niobate / Si hybrid integrated optical chip is a thin-film lithium niobate-based optical modulator.

[0080] The following embodiments are illustrative in that the optical chip 400 is an InP / Si hybrid integrated optical chip.

[0081] In InP / Si hybrid integrated optical chips, since Si is an indirect bandgap semiconductor material, its luminous efficiency is extremely low.

[0082] In some embodiments, the light source of the InP / Si hybrid integrated optical chip can be an external light source, such as Figure 5 The external light source 500 is shown. The external light source 500 is arranged on the side of the optical chip 400. The external light source 500 emits light from the side and couples it into the optical chip 400. The light emitted by the external light source 500 does not carry data. After entering the optical chip 400, the optical chip 400 performs phase modulation on the light to load the electrical signal into the light, thereby obtaining light carrying data, that is, generating an optical transmission signal, thereby achieving optical signal transmission.

[0083] In some embodiments, the light source of an InP / Si hybrid integrated optical chip can also be an internally integrated light source. Group III-V semiconductor materials are direct bandgap semiconductors with strong gain characteristics. Therefore, Group III-V materials, such as InP lasers, have excellent luminescence properties. InP lasers can be integrated within the InP / Si hybrid integrated optical chip.

[0084] Figure 6 Schematic diagram of the internal structure of an optical chip provided according to some embodiments of the present disclosure. Figure 6 As shown, an external light source 500 provides light to the optical chip 400 .

[0085] The laser light generated by the external light source 500 is coupled into the optical chip 400. The laser light is split into a first light beam and a second light beam by the optical splitter 410 integrated in the optical chip 400.

[0086] The first light beam is coupled as local oscillator light into the optical demodulator built into the optical chip 400, and the external light signal is coupled into the optical demodulator at the same time. The second light beam and the external light signal are coherently demodulated in the optical demodulator to demodulate the corresponding electrical signal.

[0087] The second light beam, serving as the light source of the optical transmission signal, is transmitted to the polarization beam splitter 430. The second light beam is split by the polarization beam splitter 430 into two beams with different polarization directions: TE polarized light and TM polarized light.

[0088] The TE polarized light is split into two beams by the beam splitter 450, and the two beams are coupled to Figure 6 The two optical modulators 460 located on the upper side of the optical module 460 perform I-modulation on the received light to generate an I-modulated signal. The lower optical modulator 460 performs Q-modulation on the received light to generate a Q-modulated signal. The I-modulated and Q-modulated signals of the light beam are combined in a combiner 471 to generate a first modulated optical signal.

[0089] The TM polarized light is split into two beams by the beam splitter 440, and the two beams are coupled to Figure 6 The two optical modulators 460 located at the bottom of the optical module 460 are used. The upper optical modulator 460 performs I-modulation on the received light to generate an I-modulated signal, while the lower optical modulator 460 performs Q-modulation on the received light to generate a Q-modulated signal. The I-modulated and Q-modulated signals of the light beam are combined in a combiner 472 to generate a second modulated optical signal.

[0090] The first modulated optical signal and the second modulated optical signal are combined by the combiner 473 to generate an optical transmit signal, thereby completing optical signal modulation.

[0091] The following embodiment uses one of the light modulators 460, such as Figure 6 The range enclosed by the middle ellipse is used as an example for illustration.

[0092] Figure 7 A top view structure of an optical modulator provided according to some embodiments of the present disclosure Figure 1 .like Figure 7 As shown, in some embodiments, one end of the optical modulator 460 is connected to a wave splitter 710 , and the other end is connected to a wave combiner 720 .

[0093] In some embodiments, the wavelength splitter 710 is disposed on one side of the optical modulator 460 to output two paths of light to be modulated to the optical modulator 460 respectively.

[0094] In some embodiments, the combiner 720 is disposed on the other side of the optical modulator 460 to combine the two optical modulation signals generated by the optical modulator 460 .

[0095] In some embodiments, optical modulator 460 is an InP-based Mach-Zehnder (MZ) modulator. MZ modulators modulate the phase by changing the refractive index of the material and then indirectly modulate the intensity of light using the principles of constructive and destructive interference. Compared to electro-absorption modulators (EAMs) and electro-absorption modulated lasers (EMLs), MZ modulators have higher modulation rates and efficiency.

[0096] The incident light of the MZ modulator is split into two paths by the demultiplexer 710, and phase modulation is performed on one of the paths or both paths simultaneously to generate a phase difference between the two paths of light, thereby achieving light intensity modulation. The modulated two paths of optical signals are combined by the combiner 720 and output.

[0097] In some embodiments, due to the low transmission loss of silicon waveguides, silicon waveguides are used as optical waveguides in InP / Si hybrid integrated optical chips.

[0098] For an optical modulator 460, the silicon waveguide includes the silicon waveguide between the output of the splitter 710 and the input of the optical modulator 460, the silicon waveguide of the optical modulator 460 itself, and the silicon waveguide between the output of the optical modulator 460 and the input of the combiner 720. These three waveguide sections are sequentially connected to form a single silicon waveguide.

[0099] The incident light of the MZ modulator is split into two paths by the demultiplexer 710, which then has two output terminals. The optical modulator 460 has two input terminals and two output terminals. The input terminal and output terminal of the optical modulator 460 are respectively located on the silicon waveguide of the optical modulator 460 itself.

[0100] In some embodiments, the silicon waveguide between the first output terminal of splitter 710 and the first input terminal of optical modulator 460 is referred to as silicon waveguide 810. The silicon waveguide after the first output terminal of optical modulator 460 is referred to as silicon waveguide 820. Silicon waveguide 810 and silicon waveguide 820 correspond to one optical signal outputted by splitter 710.

[0101] The silicon waveguide between the second output terminal of splitter 710 and the second input terminal of optical modulator 460 is called silicon waveguide 830. The silicon waveguide after the second output terminal of optical modulator 460 is called silicon waveguide 840. Silicon waveguides 830 and 840 correspond to the other optical signal output by splitter 710.

[0102] The silicon waveguide 810 , the silicon waveguide 820 , the silicon waveguide 830 , and the silicon waveguide 840 are external silicon waveguides for the optical modulator 460 .

[0103] In some embodiments, the silicon waveguide between the first input and first output of optical modulator 460 is a first silicon ridge waveguide 4613. This section of silicon waveguide is a ridge waveguide because it offers high modulation rate and efficiency. First silicon ridge waveguide 4613 corresponds to one optical signal output by splitter 710.

[0104] The silicon waveguide between the second input and second output of optical modulator 460 is a second silicon ridge waveguide 4614. This section of silicon waveguide is a ridge waveguide because of its high modulation rate and efficiency. Second silicon ridge waveguide 4614 corresponds to the other optical signal output by splitter 710.

[0105] With respect to the optical modulator 460 , the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 are silicon waveguides of the optical modulator 460 itself.

[0106] In some embodiments, the silicon waveguide 810, the first silicon ridge waveguide 4613, and the silicon waveguide 820 are continuous with each other, that is, the input end of the first silicon ridge waveguide 4613 is connected to the silicon waveguide 810 to receive the light to be modulated; and the output end is connected to the silicon waveguide 820 to output the optical modulation signal generated by the modulation.

[0107] The silicon waveguide 830, the second silicon ridge waveguide 4614, and the silicon waveguide 840 are continuous with each other, that is, the input end of the second silicon ridge waveguide 4614 is connected to the silicon waveguide 830 to receive the light to be modulated; the output end is connected to the silicon waveguide 840 to output the optical modulation signal generated by the modulation.

[0108] In some embodiments, since the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 adopt a ridge waveguide structure, in order to simplify the growth process, the silicon waveguide 810 and the silicon waveguide 820 also adopt a ridge waveguide structure, and the silicon waveguide 830 and the silicon waveguide 840 also adopt a ridge waveguide structure.

[0109] In some embodiments, to achieve modulation, the optical modulator 460 includes an N-type InP layer 462, a quantum well layer 465, and a P-type InP layer 466. The N-type InP layer 462, the quantum well layer 465, and the P-type InP layer 466 are stacked vertically in sequence.

[0110] The quantum well layer 465 is a target layer for the light to be modulated to reach, so that modulation is achieved within the quantum well layer 465. By controlling the change of the external electric field, the carriers are changed, and thus the refractive index of the quantum well layer 465 changes, thereby achieving signal modulation.

[0111] The quantum well layer 465 is located between the N-type InP layer 462 and the P-type InP layer 466. The N-type InP layer 462 and the P-type InP layer 466 arranged above each other confine the light field to the quantum well layer 465, preventing the light field from diverging.

[0112] It can be understood that the light field in the first silicon ridge waveguide 4613 will diffuse upward to the InP region, that is, the light spot will expand to the InP region. Therefore, the light to be modulated transmitted in the first silicon ridge waveguide 4613 will be coupled upward to the InP region.

[0113] Similarly, the light field in the InP region will diffuse downward into the first silicon ridge waveguide 4613 , that is, the light spot will expand to the first silicon ridge waveguide 4613 region, so the modulated optical modulation signal will be coupled downward into the first silicon ridge waveguide 4613 .

[0114] In some embodiments, the incident light of the MZ modulator is split into two paths by the wavelength splitter 710 .

[0115] One channel of light to be modulated is coupled along silicon waveguide 810 to the input end of first silicon ridge waveguide 4613. The light to be modulated within first silicon ridge waveguide 4613 is then coupled upward to quantum well layer 465 for modulation. The modulated optical signal is then coupled downward to the output end of first silicon ridge waveguide 4613 and then transmitted sequentially along first silicon ridge waveguide 4613 and silicon waveguide 820 to combiner 720.

[0116] Another path of light to be modulated is coupled along silicon waveguide 830 to the input end of second silicon ridge waveguide 4614. The light to be modulated within second silicon ridge waveguide 4614 is then coupled upward to quantum well layer 465 for modulation. The modulated optical signal is then coupled downward to second silicon ridge waveguide 4614 and then sequentially transmitted along second silicon ridge waveguide 4614 and silicon waveguide 840 to combiner 720.

[0117] The two modulated optical signals are respectively connected to the combiner 720, and are combined into one optical signal and output.

[0118] Figure 8 FIG. 1 is a structural diagram of a silicon waveguide provided according to some embodiments of the present disclosure. Figure 8 As shown, in some embodiments, the silicon waveguide adopts a ridge structure to reduce transmission loss.

[0119] When a silicon waveguide adopts a ridge structure, it consists of a silicon slab with a larger cross-sectional area and a silicon ridge with a smaller cross-sectional area. The silicon ridge is located on the surface of the silicon slab.

[0120] A complete silicon waveguide is divided into sections along the optical transmission direction. Silicon waveguide 810 and silicon waveguide 820 are respectively connected to the first input and first output of optical modulator 460; silicon waveguide 830 and silicon waveguide 840 are respectively connected to the second input and second output of optical modulator 460.

[0121] An InP modulation region of the optical modulator 460 is provided above the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614. Therefore, the two paths of light transmitted in the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 are respectively coupled upward into the InP modulation region, and then coupled downward back to the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 for output after modulation is completed.

[0122] A silicon waveguide 810 is provided between the first output end of the demultiplexer 710 and the first input end of the optical modulator 460 to couple the demultiplexed light into the optical modulator 460. A first silicon ridge waveguide 4613 is provided between the first input end and the first output end of the optical modulator 460. A silicon waveguide 820 is provided behind the first output end of the optical modulator 460 to output the optical signal modulated by the optical modulator 460.

[0123] A silicon waveguide 830 is provided between the second output end of the demultiplexer 710 and the second input end of the optical modulator 460 to couple the demultiplexed light into the optical modulator 460. A second silicon ridge waveguide 4614 is provided between the second input end and the second output end of the optical modulator 460. A silicon waveguide 840 is provided behind the second output end of the optical modulator 460 to output the modulated optical signal generated by the optical modulator 460.

[0124] One optical path output by the splitter 710 is transmitted along the silicon waveguide 810 to the input end of the first silicon ridge waveguide 4613. This light path is then coupled upward to the optical modulation area of ​​the optical modulator 460 for signal modulation. The modulated optical signal is then coupled downward back to the output end of the first silicon ridge waveguide 4613 and continues to transmit along the silicon waveguide 820 before being connected to the combiner 720.

[0125] The other light path output by splitter 710 is transmitted along silicon waveguide 830 to the input end of second silicon ridge waveguide 4614. This light path is then coupled upward to the optical modulation region of optical modulator 460 for signal modulation. The modulated optical signal is then coupled downward back to the output end of second silicon ridge waveguide 4614 and continues to transmit along silicon waveguide 840 before being connected to combiner 720.

[0126] The two modulated optical signals are respectively connected to the combiner 720, and are combined into one optical signal and output.

[0127] Figure 9 A three-dimensional structural diagram of an optical modulator provided according to some embodiments of the present disclosure; Figure 10 FIG. 1 is a cross-sectional structural diagram of an optical modulator provided according to some embodiments of the present disclosure. Figure 9 and Figure 10 As shown, in some embodiments, taking the optical chip 400 as an InP / Si hybrid integrated optical chip as an example, the InP / Si hybrid integrated optical chip has a built-in optical modulator 460 .

[0128] In some embodiments, the optical modulator 460 is an InP / Si hybrid integrated optical modulator.

[0129] The optical modulator 460 may include a silicon waveguide layer 461 at the bottom. The silicon waveguide layer 461 is the silicon waveguide of the optical modulator 460 itself, so as to fully utilize the advantage of low transmission loss of the silicon waveguide.

[0130] The optical modulator 460 may include an InP modulation region located above the silicon waveguide layer 461 to fully utilize the advantage of the high modulation rate of the InP semiconductor material.

[0131] In some embodiments, the silicon waveguide layer 461 is formed of silicon-on-insulator (SOI).

[0132] In some embodiments, the SOI waveguide includes an underlying silicon layer 4611, a buried oxide layer 4612 located on the upper surface of the underlying silicon layer 4611, and a first silicon ridge waveguide 4613 and a second silicon ridge waveguide 4614 located on either side of the upper surface of the buried oxide layer 4612. Two paths of light to be modulated are transmitted through the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614, respectively, to prevent mutual coupling between the two paths of light to be modulated.

[0133] Illustratively, the bottom silicon 4611 is a substrate layer.

[0134] Exemplarily, the buried oxide layer 4612 is a SiO2 layer. Due to the large refractive index difference between silicon and SiO2, the SOI silicon waveguide has a strong light field confinement capability, and thus the SOI silicon waveguide has low light transmission loss.

[0135] Exemplarily, the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 serve as transmission layers for the two light paths, respectively. Ridge waveguides offer low transmission loss, so a ridge waveguide structure is employed in this disclosure. It is understood that non-ridge waveguide structures may also be employed in some embodiments.

[0136] In some embodiments, the incident light of the MZ modulator is split into two paths by a wave splitter 710 at the input end.

[0137] The first output end of the demultiplexer 710 is connected to the input end of the first silicon ridge waveguide 4613 via a silicon waveguide 810 to receive one path of light outputted by the demultiplexer 710 and couple it to the first silicon ridge waveguide 4613 .

[0138] The second output end of the demultiplexer 710 is connected to the input end of the second silicon ridge waveguide 4614 via a silicon waveguide 830 to receive another path of light output by the demultiplexer 710 and couple it into the second silicon ridge waveguide 4614 .

[0139] The two paths of light to be modulated coupled and transmitted to the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 are respectively coupled upward to the InP modulation area, and after completing modulation in the InP modulation area, they are coupled downward back to the output ends of the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614. Then, the two paths of optical modulation signals generated by modulation are respectively connected to the combiner 720 along the silicon waveguide 820 and the silicon waveguide 840, and are combined into one optical signal and output.

[0140] In some embodiments, the InP modulation region comprises, from bottom to top:

[0141] N-type InP layer 462, located on the upper surface of the silicon waveguide layer 461;

[0142] stress limiting layer 463;

[0143] N-InP ohmic contact layer 464;

[0144] quantum well layer 465;

[0145] P-type InP layer 466;

[0146] P-InP ohmic contact layer 467 .

[0147] In some embodiments, the N-type InP layer 462 is an N-type doped semiconductor, such as one doped with a pentavalent element.

[0148] The P-type InP layer 466 is a P-type doped semiconductor, such as doped with a trivalent element.

[0149] The N-type InP layer 462 and the P-type InP layer 466 are doped with different impurity elements to form a PN junction.

[0150] When no forward bias voltage is applied to the PN junction, the carrier movement is in equilibrium. When a forward bias voltage is applied to the PN junction, the carrier movement equilibrium is disrupted, thereby generating an on-current. The generated on-current is applied to the quantum well layer 465.

[0151] In some embodiments, an i-InP intrinsic layer 468 is formed below the P-type InP layer 466. The i-InP intrinsic layer 468 is undoped.

[0152] A depletion region exists at the junction of the P and N regions of a PN junction. This narrow depletion region contains diffuse carriers, significantly impacting the modulation rate. By placing an i-InP intrinsic layer 468 in the middle of the PN junction, the width of the depletion region is increased, allowing carriers to drift to the PN junction under the influence of a strong electric field. This prevents the diffuse carrier component from affecting the optical modulator 460, thereby improving the modulation rate.

[0153] In some embodiments, the silicon waveguide layer 461 is grown from silicon, and the InP modulation region is an InP region. The lattice constants of the silicon material and the InP semiconductor material differ significantly, resulting in a significant lattice mismatch between the two, which results in stress during epitaxial growth of the InP material on silicon. The stress-limiting layer 463 confines the stress between the silicon and InP semiconductor materials within this layer, preventing stress from being transmitted upward to the quantum well layer 465, thereby protecting the quantum well layer 465.

[0154] In some embodiments, the quantum well layer 465 is an active region, where light to be modulated reaches the target layer to achieve modulation within the quantum well layer 465. The refractive index of the quantum well material is relatively high, and the optical signal can be well confined within the quantum well layer 465 in the longitudinal direction.

[0155] By controlling the change in the applied electric field, the carriers are changed, thereby changing the refractive index of quantum well layer 465. Since the change in the refractive index of quantum well layer 465 is proportional to the phase difference between the two modulation arms of optical modulator 460, the phase difference between the two modulation arms can be adjusted by adjusting the refractive index of quantum well layer 465.

[0156] The output light intensity varies with the phase difference between the two modulation arms, meaning that the output light intensity is modulated by the modulating electrical signal. The modulated electrical signal is modulated and converted into the output light intensity of the modulated optical signal, thus achieving modulation.

[0157] The two paths of light to be modulated transmitted to the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 are respectively coupled upward into the quantum well layer 465. After completing modulation in the quantum well layer 465, they are coupled downward back to the output ends of the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614. Then, the two modulated optical signals are respectively connected to the combiner 720 along the silicon waveguide 820 and the silicon waveguide 840, and are combined into one optical signal and output.

[0158] In some embodiments, in the InP modulation region, the area above the first silicon ridge waveguide 4613 corresponds to the first modulation arm 462a of the optical modulator 460 , and the area above the second silicon ridge waveguide 4614 corresponds to the second modulation arm 462b of the optical modulator 460 .

[0159] The quantum well layer 465 includes a first modulation partition corresponding to the first modulation arm 462a and a second modulation partition corresponding to the second modulation arm 462b. The first modulation partition modulates the light to be modulated output by the first silicon ridge waveguide 4613, and the second modulation partition modulates the light to be modulated output by the second silicon ridge waveguide 4614.

[0160] In some embodiments, the quantum well layer 465 is located between the N-type InP layer 462 and the P-type InP layer 466. The N-type InP layer 462 and the P-type InP layer 466 confine the light field from top to bottom, and confine the light field to the upper and lower regions of the quantum well layer 465. The light field does not exceed the P-type InP layer upward and does not exceed the N-type InP layer 462 downward, thereby constraining the light field and avoiding light field divergence, thereby increasing the optical coupling efficiency.

[0161] In order to increase the optical confinement effect of the P-type InP layer 466, the two light fields to be modulated are respectively confined to the first modulation partition and the second modulation partition of the quantum well layer 465, and the i-InP intrinsic layer 468, the P-type InP layer 466, and the P-InP ohmic contact layer 467 are respectively etched to obtain a first P-type InP region 466a corresponding to the upper and lower parts of the first modulation partition, and a second P-type InP region 466b corresponding to the upper and lower parts of the second modulation partition.

[0162] The first P-type InP region 466a and the second P-type InP region 466b protrude relative to the quantum well layer 465, forming a ridge structure. For ease of description, the first P-type InP region 466a includes, from bottom to top, an i-InP intrinsic layer 468, a P-type InP layer 466, and a P-InP ohmic contact layer 467; the second P-type InP region 466b includes, from bottom to top, an i-InP intrinsic layer 468, a P-type InP layer 466, and a P-InP ohmic contact layer 467.

[0163] In some embodiments, a P-type electrode 4671 is provided on the surface of the P-InP ohmic contact layer 467 in the first P-type InP region 466 a , and a P-type electrode 4671 is provided on the surface of the P-InP ohmic contact layer 467 in the second P-type InP region 466 b .

[0164] The width of the N-InP ohmic contact layer 464 is greater than the width of the quantum well layer 465, so there is a gap at both ends of the N-InP ohmic contact layer 464 relative to the end of the quantum well layer 465, and then an N-type electrode 4641 can be formed at both ends of the N-InP ohmic contact layer 464.

[0165] In some embodiments, the optical modulator 460 may include an intermediate bonding layer 469. The intermediate bonding layer 469 is located between the silicon waveguide layer 461 and the InP modulation region.

[0166] The silicon waveguide layer 461 is grown from silicon, and the InP modulation region is an InP region. The lattice constants of silicon and InP semiconductor materials differ significantly, resulting in a significant lattice mismatch. This leads to stress during epitaxial growth of InP on silicon, resulting in poor hybrid integration quality. To address this, an intermediate bonding layer 469 is placed between the silicon waveguide layer 461 and the InP modulation region.

[0167] The intermediate bonding layer 469 is located between the silicon material and the InP semiconductor material. The silicon material and the InP semiconductor material are bonded together by the bonding force between the intermediate bonding layer 469 and the silicon material and the InP semiconductor material, such as van der Waals force or chemical bond, to achieve hybrid integration of the silicon material and the InP semiconductor material.

[0168] For example, the middle bonding layer 469 is a SiO 2 layer. SiO 2 has good hydrophilicity and can form stable covalent bonds at lower temperatures, thereby achieving higher bonding strength and a good bonding interface.

[0169] In the present disclosure, the growth material of the silicon waveguide layer 461 in the optical modulator 460 is silicon, and the InP modulation region is an InP region, so the optical modulator 460 is an InP / Si hybrid integrated optical modulator.

[0170] Silicon waveguide and InP waveguide are waveguides made of different materials, and their optical field modes are different. Therefore, when light is coupled between the silicon waveguide and the InP waveguide, there is a large mode mutation, a mode field mismatch, and a large coupling loss.

[0171] For example, when the light to be modulated is coupled upward from the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 to the quantum well layer 465, a certain loss is generated, and when the optical modulation signal is coupled downward from the quantum well layer 465 back to the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614, a certain loss is generated again, thereby reducing the optical coupling efficiency.

[0172] Figure 11 A top view of a light modulator 460 according to some embodiments of the present disclosure Figure 2 .like Figure 11 As shown, in some embodiments, the optical modulator 460 includes, from bottom to top, a silicon waveguide layer 461 , an N-type InP layer 462 , a quantum well layer 465 , and a P-type InP layer 466 .

[0173] In some embodiments, in order to increase the optical confinement effect of the P-type InP layer 466, the two paths of light fields to be modulated are confined to the first modulation partition and the second modulation partition of the quantum well layer 465, respectively. The P-type InP layer 466 can be divided into two independent structures corresponding to the two paths of light fields to be modulated, as if Figure 11 The first P-type InP region 466a and the second P-type InP region 466b are shown.

[0174] In the present disclosure, each layer of waveguide of the optical modulator 460 toward the demultiplexer 710 and toward the combiner 720 is formed with a gradient structure, and the silicon waveguide and the InP region waveguide at the same end present opposite gradient trends to reduce mode mutations when light is coupled between the silicon waveguide and the InP waveguide, thereby achieving low-loss coupling of light between the silicon waveguide and the InP waveguide.

[0175] In the coupling region at one end of the optical modulator 460, that is, toward the end of the demultiplexer 710, the waveguide widths of the first and second silicon ridge waveguides 4613 and 4614 gradually narrow, while the waveguide widths of the various layers of the InP region gradually widen. This squeezes the optical field energy in the silicon ridge waveguide into the InP region waveguide, coupling more of the optical field energy to be modulated upward into the InP region for modulation. Maximum optical coupling efficiency is achieved when the refractive index of the silicon ridge waveguide and the InP region waveguide are equal at a certain moment.

[0176] In the coupling region at the other end of the optical modulator 460, that is, toward the combiner 720, the waveguide widths of the first and second silicon ridge waveguides 4613 and 4614 gradually widen, while the waveguide widths of the various layers in the InP region gradually narrow. This squeezes the light field energy of the InP region waveguide into the silicon ridge waveguide, coupling more modulated light field energy downward into the silicon ridge waveguide for output. Maximum optical coupling efficiency occurs when the refractive index of the silicon ridge waveguide and the InP region waveguide are equal at a certain moment.

[0177] In the middle coupling region of the optical modulator 460 , each waveguide is not designed with a gradient structure, so as to maintain the light field energy within the coupling region for modulation.

[0178] For ease of description, the end of the optical modulator 460 facing the demultiplexer 710 is referred to as the first end, and the end of the optical modulator 460 facing the combiner 720 is referred to as the second end. The coupling region corresponding to the first end is referred to as the first tapered coupling region 460a, and the coupling region corresponding to the second end is referred to as the second tapered coupling region 460c.

[0179] In some embodiments, a waveguide gradient structure is formed at the first end of the optical modulator 460 to gradually change the waveguide dimensions of each layer in the first gradient coupling region, thereby reducing the ability of the silicon ridge waveguide in the first gradient coupling region 460a to restrict the light field and increasing the ability of the InP waveguide to restrict the light field, so that more light fields to be modulated in the silicon ridge waveguide in the first gradient coupling region 460a can be squeezed into the InP modulation region for modulation.

[0180] In some embodiments, a waveguide gradient structure is formed at the second end of the optical modulator 460 to gradually change the waveguide dimensions of each layer in the second gradient coupling region, thereby reducing the ability of the InP waveguide in the second gradient coupling region 460c to restrict the light field and increasing the ability of the silicon ridge waveguide to restrict the light field. In this way, the modulated light field of the InP modulation region in the second gradient coupling region 460c is squeezed into the silicon ridge waveguide to output the modulated light signal.

[0181] The waveguide layers at both ends of the optical modulator 460 are formed with gradient structures, and the silicon waveguide and the InP region waveguide in the coupling region at the same end show opposite gradient trends, which can reduce the optical loss of coupling from the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 upward to the quantum well layer 465, and at the same time reduce the optical loss of coupling from the quantum well layer 465 downward to the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614, thereby achieving low-loss coupling.

[0182] Figure 12 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 1 ; Figure 13 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 2 .like Figure 12 and Figure 13 As shown, the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 , the N-type InP layer 462 , the quantum well layer 465 , and the P-type InP layer 466 in the same layer are stacked in sequence.

[0183] In some embodiments, the waveguide width of the N-type InP layer 462 is relatively large to provide better support.

[0184] In some embodiments, the incident light of the MZ modulator is split into two paths by the wave splitter 710, and the wave splitter 710 has two output terminals. The optical modulator 460 correspondingly has two input terminals and two output terminals.

[0185] In some embodiments, the silicon waveguide layer 461 has a silicon contraction region 4615 for receiving two modulated lights at one end facing the demultiplexer 710 , and a silicon expansion region 4616 for coupling two optical modulated signals at one end facing the combiner 720 .

[0186] In some embodiments, the N-type InP layer 462 has a first InP expansion region 4621 corresponding to coupling two modulated lights at one end facing the demultiplexer 710 , and a first InP contraction region 4623 corresponding to coupling two optical modulation signals at one end facing the combiner 720 .

[0187] In some embodiments, the quantum well layer 465 has a second InP expansion region 4651 corresponding to coupling two modulated lights at one end facing the demultiplexer 710 , and a second InP contraction region 4653 corresponding to coupling two optical modulation signals at one end facing the combiner 720 .

[0188] In some embodiments, the P-type InP layer 466 has a third InP expansion region 4661 corresponding to coupling two modulated lights at one end facing the demultiplexer 710 , and a third InP contraction region 4663 corresponding to coupling two optical modulation signals at one end facing the combiner 720 .

[0189] The silicon contraction region 4615, the first InP expansion region 4621, the second InP expansion region 4651, and the third InP expansion region 4661 corresponding to a path of light to be modulated are stacked vertically in sequence to couple the light to be modulated in the silicon contraction region 4615 upward to the quantum well layer 465 for signal modulation.

[0190] The silicon expansion region 4616, the first InP contraction region 4623, the second InP contraction region 4653, and the third InP contraction region 4663 corresponding to one optical modulation signal are stacked vertically in sequence to couple the optical modulation signal generated by the modulation of the quantum well layer downward to the silicon expansion region for output.

[0191] In some embodiments, the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 have the same structure. As previously described, the silicon ridge waveguide comprises a silicon slab with a larger cross-sectional area and a silicon ridge with a smaller cross-sectional area. The silicon slab and the silicon ridge have the same gradient structure. The gradient structure of the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 is described below using the silicon slab as an example.

[0192] In some embodiments, to increase the coupling efficiency between the silicon waveguide and the InP waveguide, the first silicon ridge waveguide 4613 has a silicon contraction region 4615 at the input end, a silicon expansion region 4616 at the output end, and a silicon flat region 4617 in the middle.

[0193] The N-type InP layer 462 includes two symmetrical partitions to couple the two optical signals. The two symmetrical partitions have the same structure. In the N-type InP layer 462, the corresponding ends of the two optical paths have a first InP expansion region 4621 at the end facing the splitter 710, a first InP contraction region 4623 at the end facing the combiner 720, and a first InP flat region 4622 in the middle.

[0194] The quantum well layer 465 is used to modulate the two optical signals separately. The quantum well layer 465 includes a first modulation partition and a second modulation partition that are symmetrically arranged to modulate the two optical signals separately. The first modulation partition and the second modulation partition have the same structure. In the quantum well layer 465, the corresponding ends of the two light paths are: the end facing the splitter 710 has a second InP expansion region 4651, the end facing the combiner 720 has a second InP contraction region 4653, and the middle has a second InP flat region 4652. Among them, the second InP expansion region 4651 is a coupling structure at one end of the quantum well layer 465; the second InP contraction region 4653 is a coupling structure at the other end of the quantum well layer 465; the second InP flat region 4652 is an effective modulation structure of the quantum well layer 465, and the light to be modulated is modulated in the second InP flat region 4652.

[0195] In the P-type InP layer 466 , the corresponding ends of the two light paths have a third InP expansion region 4661 at the end facing the demultiplexer 710 , a third InP contraction region 4663 at the end facing the combiner 720 , and a third InP flat region 4662 in the middle.

[0196] The term "contraction" means that the waveguide width gradually narrows along the direction from splitter 710 to combiner 720. The term "expansion" means that the waveguide width gradually widens along the direction from splitter 710 to combiner 720. The meanings of the aforementioned contraction and expansion regions all fall within this interpretation.

[0197] In the coupling region of the optical modulator 460 toward the demultiplexer 710 , the silicon contraction region 4615 , the first InP expansion region 4621 , the second InP expansion region 4651 , and the third InP expansion region 4661 are stacked vertically in sequence.

[0198] In the output coupling region of the optical modulator 460 , the silicon expansion region 4616 , the first InP contraction region 4623 , the second InP contraction region 4653 , and the third InP contraction region 4663 are stacked vertically in sequence.

[0199] In the middle region of the optical modulator 460 , a silicon flat region 4617 , a first InP flat region 4622 , a second InP flat region 4652 , and a third InP flat region 4662 are stacked vertically in sequence.

[0200] The purpose of setting the above-mentioned contraction zone and expansion zone is to reduce the sudden change of the coupling zone mode, while the purpose of setting the flat zone is to maintain the current light field mode.

[0201] In some embodiments, the first tapered coupling region 460a of the optical modulator 460 includes, from bottom to top, a silicon contraction region 4615, a first InP expansion region 4621, a second InP expansion region 4651, and a third InP expansion region 4661.

[0202] In the first tapered coupling region 460a, the width of the silicon waveguide gradually narrows, and thus the effective refractive index of the silicon waveguide at the input end gradually decreases, the ability to limit light waves gradually weakens, and the light field area gradually increases.

[0203] The first InP expansion region 4621, the second InP expansion region 4651, and the third InP expansion region 4661 form the waveguide structures of each layer of the InP region. Within the first tapered coupling region 460a, the width of each InP waveguide layer gradually increases, and the effective refractive index of each InP waveguide layer gradually increases, gradually strengthening the ability to confine light waves. This squeezes the light field from the silicon waveguide into the InP region within the first tapered coupling region 460a, thereby performing signal modulation.

[0204] In the present disclosure, in the first gradient coupling region 460a of the optical modulator 460, each waveguide is provided with a gradient structure, thereby reducing the mode mutation of the modulated light between the silicon waveguide and the InP waveguide, and realizing low-loss coupling in the coupling region.

[0205] In some embodiments, the second tapered coupling region 460 c of the optical modulator 460 includes, from bottom to top, a silicon expansion region 4616 , a first InP contraction region 4623 , a second InP contraction region 4653 , and a third InP contraction region 4663 .

[0206] In the second tapered coupling region 460c, the width of the silicon waveguide gradually widens, and thus the effective refractive index of the silicon waveguide at the output end gradually increases, and the ability to confine light waves gradually increases.

[0207] The first InP contraction region 4623, the second InP contraction region 4653, and the third InP contraction region 4663 form the waveguide structures of each layer of the InP region. Within the second tapered coupling region 460c, the width of each waveguide layer in the InP region gradually narrows, and the effective refractive index of each waveguide layer in the InP region gradually decreases, gradually weakening the ability to confine light waves. As a result, within the second tapered coupling region 460c, the light field is squeezed from the InP region to the silicon waveguide to transmit the modulated optical signal.

[0208] In the present disclosure, in the second tapered coupling region 460c of the optical modulator 460, each waveguide is provided with a tapered structure, thereby reducing the mode mutation of the optical modulated signal between the silicon waveguide and the InP waveguide, and achieving low-loss coupling in the coupling region.

[0209] Figure 14 Schematic diagram of the optical path of an optical modulator according to some embodiments of the present disclosure. Figure 14 As shown, the optical path is exemplarily described below by taking an optical signal output by the demultiplexer 710 as an example.

[0210] The vertically stacked silicon flat region 4617, the first InP flat region 4622, the second InP flat region 4652, and the third InP flat region 4662 constitute the light modulation region 460b of the light modulator 460. The second InP flat region 4652 is a structure that substantially performs signal modulation.

[0211] The silicon contraction region 4615 , the first InP expansion region 4621 , the second InP expansion region 4651 , and the third InP expansion region 4661 stacked vertically constitute a first tapered coupling region 460 a .

[0212] The silicon expansion region 4616 , the first InP contraction region 4623 , the second InP contraction region 4653 , and the third InP contraction region 4663 stacked vertically constitute the second tapered coupling region 460 c .

[0213] By providing a first tapered coupling region 460 a at one end facing the wave splitter 710 , more optical field energy to be modulated is transferred from the silicon waveguide to the InP region for modulation.

[0214] By providing a second tapered coupling region 460 c at the end facing the combiner 720 , more modulated optical field energy is released from the InP region into the silicon waveguide.

[0215] The light modulation region 460b of the light modulator 460 is flat without any gradient, so as to ensure that the energy is maintained within this region.

[0216] The first gradient coupling region 460a is used to couple the light to be modulated upward to the light modulation region 460b.

[0217] The second tapered coupling region 460c is used to couple the optical modulation signal downward from the optical modulation region 460b.

[0218] In the first gradient coupling region 460a, the width of the silicon waveguide is gradually narrowed while the width of the InP waveguide is gradually widened, so that the light to be modulated is coupled upward from the silicon waveguide to the second InP flat region 4652 for signal modulation to generate an optical modulation signal.

[0219] In the second tapered coupling region 460c, the width of the InP waveguide is gradually narrowed while the width of the silicon waveguide is gradually widened, so as to couple the optical modulated signal downward from the second InP flat region 4652 to the silicon waveguide to output the optical modulated signal.

[0220] In some embodiments, an optical signal output by the demultiplexer 710 enters the silicon contraction region 4615 along the silicon waveguide 810, is upwardly coupled to the first InP expansion region 4621 and the second InP expansion region 4651 in sequence, and then is laterally coupled to the second InP flat region 4652 on the same layer as the second InP expansion region 4651, and signal modulation is performed in the second InP flat region 4652.

[0221] The optical modulated signal is laterally coupled from the second InP flat region 4652 to the second InP contraction region 4653 in the same layer. From the second InP contraction region 4653, the optical modulated signal is sequentially coupled downward to the first InP contraction region 4623 and the silicon expansion region 4616, and then enters the silicon waveguide 820 in the same layer as the silicon expansion region 4616, where it is output along the silicon waveguide 820.

[0222] It is understandable that, in some embodiments, the first tapered coupling region 460 a of the optical modulator 460 may be in the form of a coupler independent of the optical modulator 460 , that is, a coupler is provided at one end of the optical modulator 460 facing the wavelength splitter 710 .

[0223] Likewise, the second tapered coupling region 460 c of the optical modulator 460 may also be in the form of a coupler independent of the optical modulator 460 , that is, another coupler is provided at the end of the optical modulator 460 facing the combiner 720 .

[0224] The structures of these two separate couplers are the same as the structure of the optical modulator 460 , except that these two couplers are passive devices and do not require P-type electrodes and N-type electrodes.

[0225] Figure 15 FIG1 is a schematic diagram of a gradual change of a silicon waveguide according to some embodiments of the present disclosure. Figure 15 As shown, in some embodiments, the silicon waveguide 810 , the first silicon ridge waveguide 4613 , and the silicon waveguide 820 correspond to one of the light paths output by the splitter 710 .

[0226] In some embodiments, the first silicon ridge waveguide 4613 has a silicon contraction region 4615 at the input end, a silicon expansion region 4616 at the output end, and a silicon flat region 4617 in the middle. The waveguide width is narrowest at the location of the silicon flat region 4617.

[0227] The silicon contraction region 4615 is used to squeeze the light field to be modulated upward to the quantum well layer 465 by gradually contracting the waveguide width, and the silicon expansion region 4616 is used to "attract" the modulated light field in the quantum well layer 465 downward by gradually expanding the waveguide width, thereby increasing the optical coupling efficiency between the silicon waveguide and the InP waveguide.

[0228] Figure 16 FIG. 1 is a structural diagram of an N-type InP layer provided according to some embodiments of the present disclosure. Figure 16 As shown, in some embodiments, both ends of the N-type InP layer 462 have a gradient structure.

[0229] The N-type InP layer 462 includes two symmetrical partitions with the same structure to transmit two optical signals respectively.

[0230] In the N-type InP layer 462 , the two corresponding ends of the light beam have a first InP expansion region 4621 at the end facing the demultiplexer 710 , a first InP contraction region 4623 at the end facing the combiner 720 , and a first InP flat region 4622 in the middle.

[0231] The first InP expansion region 4621 is used to attract the modulated light field upward to the quantum well layer 465 by gradually expanding the waveguide width, and the first InP contraction region 4623 is used to squeeze the modulated light field in the quantum well layer 465 downward to the silicon waveguide for output by gradually contracting the waveguide width, thereby increasing the optical coupling efficiency between the silicon waveguide and the InP waveguide.

[0232] Figure 17 FIG. 1 is a structural diagram of a quantum well layer according to some embodiments of the present disclosure. Figure 17 As shown, in some embodiments, the input end and the output end of the quantum well layer 465 each have a gradient structure.

[0233] The quantum well layer 465 includes a first modulation partition and a second modulation partition that are symmetrically arranged to modulate two optical signals respectively. The first modulation partition and the second modulation partition have the same structure.

[0234] In the quantum well layer 465 , the corresponding ends of the two light paths have a second InP expansion region 4651 at the end facing the demultiplexer 710 , a second InP contraction region 4653 at the end facing the combiner 720 , and a second InP flat region 4652 in the middle.

[0235] The second InP expansion region 4651 is a coupling structure at one end of the quantum well layer 465; the second InP contraction region 4653 is a coupling structure at the other end of the quantum well layer 465; the second InP flat region 4652 is an effective modulation structure of the quantum well layer 465, and the light to be modulated is modulated in the second InP flat region 4652.

[0236] The second InP expansion region 4651 is used to attract the modulated light field upward to the quantum well layer 465 by gradually expanding the waveguide width, and the second InP contraction region 4653 is used to squeeze the modulated light field in the quantum well layer 465 downward to the silicon waveguide for output by gradually contracting the waveguide width, thereby increasing the optical coupling efficiency between the silicon waveguide and the InP waveguide.

[0237] Figure 18 FIG. 1 is a structural diagram of a P-type InP layer provided according to some embodiments of the present disclosure. Figure 18 As shown, in some embodiments, in the P-type InP layer 466, the corresponding ends of the two light paths are: the end facing the demultiplexer 710 has a third InP expansion region 4661, the end facing the combiner 720 has a third InP contraction region 4663, and the middle has a third InP flat region 4662.

[0238] The third InP expansion region 4661 is used to attract the modulated light field upward to the quantum well layer 465 by gradually expanding the waveguide width, and the third InP contraction region 4663 is used to squeeze the modulated light field in the quantum well layer 465 downward to the silicon waveguide for output by gradually contracting the waveguide width, thereby increasing the optical coupling efficiency between the silicon waveguide and the InP waveguide.

[0239] As previously mentioned, the light source of the InP / Si hybrid integrated optical chip can also be an internally integrated light source. Group III-V semiconductor materials are direct bandgap semiconductors with strong gain characteristics. Therefore, Group III-V materials have excellent luminescence properties, such as InP lasers. Therefore, an InP laser can be integrated within the InP / Si hybrid integrated optical chip.

[0240] Figure 19 This is a schematic diagram of the structure of a modulator integrated within an optical chip according to some embodiments of the present disclosure. Figure 19 As shown, a laser 480 is integrated into the optical chip 400. By way of example, the laser 480 is an InP laser.

[0241] The laser 480 is integrated into the optical chip 400. The laser light outputted by the laser 480 is transmitted to the optical modulator 460 for signal modulation. The optical modulator 460 may have the first tapered coupling region 460a and the second tapered coupling region 460c formed at both ends thereof.

[0242] The light output from laser 480 is transmitted to splitter 710. The two optical beams output from splitter 710 are coupled to optical modulator 460 for signal modulation. The two optical signals generated after modulation are coupled to combiner 720. Combiner 720 combines the two optical modulated signals into a single optical beam and outputs it.

[0243] The optical chip 400 integrates both the laser 480 and the optical modulator 460 , thereby having both light emitting and signal modulation functions, and completing light emitting and signal modulation in the same chip.

[0244] In this disclosure, the lasers corresponding to each channel are integrated within a hybrid integrated optical chip to increase integration. Furthermore, each channel has a laser, which reduces local power density and thermal stress, thereby improving the reliability of the hybrid integrated optical chip and making it suitable for multi-channel transmission.

[0245] Figure 20 A schematic diagram of a cross-sectional structure of a laser provided according to some embodiments of the present disclosure; Figure 21 FIG. 1 is a partial schematic diagram of a laser provided according to some embodiments of the present disclosure. Figure 20-21 As shown, in some embodiments, the layers of the laser 480 are formed from the same material as the layers of the laser 480.

[0246] In some embodiments, in some embodiments, the laser 480 is an InP / Si hybrid integrated laser.

[0247] In some embodiments, the laser 480 may include a waveguide layer at the bottom. For example, the waveguide layer is a silicon waveguide layer 481, which is the silicon waveguide of the laser 480 itself, so as to fully utilize the advantage of low transmission loss of silicon waveguide.

[0248] In some embodiments, the laser 480 may include an InP light emitting region located above the silicon waveguide layer 481 , taking full advantage of the gain characteristics of the InP semiconductor material.

[0249] In some embodiments, the silicon waveguide layer 481 is formed of silicon-on-insulator (SOI).

[0250] In some embodiments, the SOI waveguide includes: an underlying silicon layer 4811 , a buried oxide layer 4812 located on the upper surface of the underlying silicon layer 4811 , and silicon ridge waveguides 4813 located on the upper surface of the buried oxide layer 4812 .

[0251] Illustratively, the bottom silicon 4811 is the substrate layer.

[0252] Exemplarily, the buried oxide layer 4812 is a SiO2 layer. Due to the large refractive index difference between silicon and SiO2, the SOI silicon waveguide has a strong light field confinement capability, and thus the SOI silicon waveguide has low light transmission loss.

[0253] Based on the low transmission loss of ridge waveguide, the present disclosure adopts a ridge waveguide structure. It is understood that in some embodiments, a non-ridge waveguide structure can also be used.

[0254] In some embodiments, the InP light emitting region comprises, from bottom to top:

[0255] N-type InP layer 482, located on the upper surface of the silicon waveguide layer 481;

[0256] stress limiting layer 483;

[0257] N-InP ohmic contact layer 484;

[0258] quantum well layer 485;

[0259] P-type InP layer 486;

[0260] P-InP ohmic contact layer 4862.

[0261] In some embodiments, the N-type InP layer 482 is an N-type doped semiconductor, such as one doped with a pentavalent element.

[0262] The P-type InP layer 486 is a P-type doped semiconductor, such as doped with a trivalent element.

[0263] The N-type InP layer 482 and the P-type InP layer 486 are doped with different impurity elements to form a PN junction.

[0264] In some embodiments, when a PN junction is formed, the carrier concentration difference causes diffusion motion. This carrier diffusion motion results in the following: the P-type InP layer 486 contains holes and negative ions, while the N-type InP layer 482 contains electrons and positive ions. Based on the charge principle, holes are driven downward into the quantum well layer 485, while electrons are driven upward into the quantum well layer 485.

[0265] Within quantum well layer 485, stimulated emission causes discrete electron-hole pairs to recombine, generating photons. This effectively converts electrically injected carriers into photons and generates gain light. The photons recombined within quantum well layer 485 are reflected by the resonant cavity or distributed feedback grating, forming positive feedback, thereby generating lasing light.

[0266] In some embodiments, in order to enable the laser 480 to emit light of a specific wavelength, a grating layer 488 is further formed on the surface of the silicon ridge waveguide 4813. Exemplarily, the grating layer 488 is a Bragg grating.

[0267] In some embodiments, by changing the current injected into the grating layer 488 , the effective refractive index of the grating layer 488 can be changed, thereby changing the resonant lasing wavelength of the laser 480 , thereby achieving the selection of a specific wavelength.

[0268] In some embodiments, an undoped i-InP intrinsic layer 4861 is formed below the P-type InP layer 486 .

[0269] A depletion region exists at the junction of the P and N regions of a PN junction. This narrow depletion region contains diffuse carriers, significantly impacting the modulation rate. By placing an i-InP intrinsic layer 4861 in the middle of the PN junction, the depletion region width is increased, allowing carriers to drift to the PN junction under the influence of a strong electric field. This prevents the influence of diffuse carriers on the laser 480, thereby increasing the modulation rate.

[0270] In some embodiments, the silicon waveguide layer 481 is grown from silicon, and the InP light-emitting region is an InP region. The lattice constants of the silicon material and the InP semiconductor material differ significantly, resulting in a significant lattice mismatch between the two, which results in stress during epitaxial growth of the InP material on silicon. The stress-limiting layer 483 confines the stress between the silicon and InP semiconductor materials within this layer, preventing stress from being transmitted upward to the quantum well layer 485, thereby protecting the quantum well layer 485.

[0271] In some embodiments, the quantum well layer 485 is an active region, where carriers reach the target layer and recombine to generate photons within the quantum well layer 485. The refractive index of the quantum well material is relatively high, and the optical signal can be well confined within the quantum well layer 485 in the longitudinal direction.

[0272] In some embodiments, a P-type electrode 487 a is provided on the surface of the P-InP ohmic contact layer 4862 .

[0273] The width of the N-InP ohmic contact layer 484 is greater than the width of the quantum well layer 485, so there is a gap at both ends of the N-InP ohmic contact layer 484 relative to the end of the quantum well layer 485, and then an N-type electrode 487b can be formed at both ends of the N-InP ohmic contact layer 484.

[0274] In some embodiments, the laser 480 may include an intermediate bonding layer 489. The intermediate bonding layer 489 is located between the silicon waveguide layer 481 and the InP light emitting region.

[0275] The silicon waveguide layer 481 is grown from silicon, and the InP modulation region is an InP region. The lattice constants of silicon and InP semiconductor materials differ significantly, resulting in a significant lattice mismatch. This leads to stress during epitaxial growth of InP on silicon, resulting in poor hybrid integration quality. To address this, an intermediate bonding layer 489 is placed between the silicon waveguide layer 481 and the InP light-emitting region.

[0276] The intermediate bonding layer 489 is located between the silicon material and the InP semiconductor material. The silicon material and the InP semiconductor material are bonded together by the bonding force between the intermediate bonding layer 489 and the silicon material and the InP semiconductor material, such as van der Waals force or chemical bond, to achieve hybrid integration of the silicon material and the InP semiconductor material.

[0277] For example, the middle bonding layer 489 is a SiO2 layer. SiO2 has good hydrophilicity and can form stable covalent bonds at lower temperatures, thereby achieving higher bonding strength and a good bonding interface.

[0278] In some embodiments, the optical confinement factor of the silicon waveguide layer 481 is greater than that of the quantum well layer 485 , so the optical field in the quantum well layer 485 is larger and can be coupled downward into the silicon waveguide layer 481 .

[0279] In some embodiments, the optical field generated by the quantum well layer 485 is relatively large and can be coupled downwardly into the silicon waveguide layer 481. For example, when the propagation constant of the quantum well layer 485 is the same as the propagation constant of the silicon waveguide layer 481, the coupling efficiency between the quantum well layer 485 and the silicon waveguide layer 481 is relatively high.

[0280] In some embodiments, the silicon waveguide layer 481 and the quantum well layer 485 can be designed as waveguides with opposite gradient trends. When the effective refractive indices of the two are gradiented to the same, that is, when the transmission constants of the two are the same, the coupling efficiency between the two is the highest.

[0281] In some embodiments, the laser 480 emits light downward from the quantum well layer 485 and then outputs horizontally through the silicon waveguide layer 481 .

[0282] In some embodiments, the laser light output by the silicon waveguide layer 481 is a laser that does not carry a signal. The silicon waveguide layer 481 is coupled to the wave splitter 710, thereby transmitting the laser light output by the laser 480 to the wave splitter 710. The wave splitter 710 splits the laser light into two paths, each of which is transmitted to the optical modulator 460 for signal modulation.

[0283] In some embodiments, based on the above laser, the laser 480 can be integrated into a hybrid integrated optical chip, and the hybrid integrated optical chip includes the laser 480 , a wavelength splitter 710 , an optical modulator 460 , and a wavelength combiner 720 .

[0284] In some embodiments, a splitter 710 is disposed on the output optical path of the laser 480 to receive the light output by the waveguide layer of the laser 480 and split the light into two paths of light to be modulated. An optical modulator 460 is disposed on the output optical path of the splitter 710 to receive the two paths of light to be modulated and modulate the two paths of light to be modulated. A combiner 720 is disposed on one side of the optical modulator 460 to combine the two optical modulated signals generated by the optical modulator 460.

[0285] In some embodiments, the optical modulator 460 may have the first tapered coupling region 460 a and the second tapered coupling region 460 c formed at both ends, and the structure thereof will not be further described.

[0286] Figure 22 Schematic diagram of a structure of an integrated heater inside an optical modulator according to some embodiments of the present disclosure. Figure 22 As shown, a first heating portion 491 and a second heating portion 492 are respectively formed on both sides of the light modulator 460. The first tapered coupling region 460a and the second tapered coupling region 460c are respectively formed on both ends of the light modulator 460.

[0287] In some embodiments, a first heating portion 491 and a second heating portion 492 are respectively formed on two sides of the P-type InP layer 466 .

[0288] In some embodiments, a first heating portion 491 is formed on one side of the first P-type InP region 466 a , and a second heating portion 492 is formed on one side of the second P-type InP region 466 b .

[0289] In some embodiments, the hybrid integrated optical chip is temperature-controlled using a TEC to maintain its operating temperature within a certain range. However, temperature control using a TEC consumes significant power. In the present disclosure, based on the fact that InP semiconductor materials are more sensitive to temperature than Si-based materials, the temperature of a portion of the optical chip, namely the first P-type InP region 466a and the second P-type InP region 466b, is controlled, rather than the entire optical chip. This allows the optical chip to operate within a certain temperature range while reducing power consumption.

[0290] In this disclosure, based on the fact that InP semiconductor materials are more sensitive to temperature than Si materials, the temperature of the optical chip is adjusted locally, rather than for the entire chip, to keep the chip operating within a certain temperature range. This achieves the goal of regulating the temperature of the entire optical chip, thereby reducing power consumption.

[0291] The heat generated by the first heating unit 491 heats the first P-type InP region 466a, and the heat generated by the second heating unit 492 heats the second P-type InP region 466b, thereby heating each InP modulation region. By regulating the temperature of the InP modulation region, the temperature of the entire optical chip is regulated.

[0292] The first heating unit 491 and the second heating unit 492 regulate the temperature of a localized area of ​​the optical chip, the InP modulation region, allowing the optical chip to operate within a specific temperature range using a low-power approach. Furthermore, regulating the temperature of the InP modulation region reduces thermal stress during bonding between the InP modulation region and the Si-based substrate, thereby improving the reliability and modulation rate of the optical modulator 460.

[0293] The first heating unit 491 is disposed adjacent to the first P-type InP region 466a to regulate the temperature of the first P-type InP region 466a and thereby regulate the temperature of a local area of ​​the optical chip, thereby maintaining the entire optical chip within a certain temperature range.

[0294] The second heating unit 492 is disposed adjacent to the first P-type InP region 466a to regulate the temperature of the first P-type InP region 466a and thereby regulate the temperature of a local area of ​​the optical chip, thereby maintaining the entire optical chip within a certain temperature range.

[0295] In some embodiments, a temperature sensor is embedded within the Si-based platform to monitor the temperature of the InP modulation region in real time. The temperature sensor collects the temperature of the InP modulation region in real time, thereby adjusting the temperature of the InP modulation region in real time, thereby achieving closed-loop control of temperature regulation.

[0296] In some embodiments, the first heating unit 491 and the second heating unit 492 may be in the form of heating resistors, which heat the first P-type InP region 466a and the second P-type InP region 466b respectively.

[0297] In some embodiments, to provide power to the first heating unit 491 and the second heating unit 492, metal vias are provided in the layer where the first heating unit 491 and the second heating unit 492 are located. The metal vias are connected to the power supply metal area of ​​the optical chip, thereby heating the first heating unit 491 and the second heating unit 492.

[0298] In some embodiments, the regions where the first and second heating portions 491 and 492 are located are epitaxially grown from SiO2 materials, while the underlying silicon 4611 is also epitaxially grown from Si materials. The thermal conductivity of Si is greater than that of SiO2, meaning that the thermal conductivity of the underlying silicon 4611 is greater than that of the regions where the heating portions are located. Consequently, the heat generated by the first and second heating portions 491 and 492 is transferred downward to the underlying silicon 4611, reducing the efficiency of temperature regulation.

[0299] In some embodiments, a first heat isolating portion 493 is formed on one side of the first heating portion 491. The first heat isolating portion 493 penetrates downward to the underlying silicon 4611 to reduce heat conducted downward from the first heating portion 491 to the underlying silicon 4611.

[0300] A second heat isolating portion 494 is formed on one side of the second heating portion 492. The second heat isolating portion 494 extends downward from the cladding layer 414 to the underlying silicon 4611 to reduce heat conducted downward from the second heating portion 492 to the underlying silicon 4611.

[0301] In some embodiments, the first thermal isolation portion 493 and the second thermal isolation portion 494 can be in the form of a groove-like structure. The first thermal isolation portion 493 and the second thermal isolation portion 494 are obtained by hollowing out downward. The first thermal isolation portion 493 and the second thermal isolation portion 494 extend downward to the underlying silicon 4611. The area below the first heating portion 491 is not hollowed out to ensure the support of the first heating portion 491. The area below the second heating portion 492 is not hollowed out to ensure the support of the second heating portion 4311.

[0302] The medium within the first thermal isolation portion 493 and the second thermal isolation portion 494 is air, which has an extremely low thermal conductivity. The thermal conductivity of air is less than that of SiO2 material, and the thermal conductivity of air is less than that of InP material. Therefore, the amount of heat generated by the first heating portion 491 and the second heating portion 492 that is conducted downward is very small, and the first thermal isolation portion 493 and the second thermal isolation portion 494 can block the path for downward heat conduction. Furthermore, the heat generated by the first heating portion 491 and the second heating portion 492 can be well concentrated near the first P-type InP region 466a and the second P-type InP region 466b, respectively, thereby improving the temperature regulation efficiency.

[0303] In some embodiments, the first thermal isolation portion 493 includes a first connecting groove 4931 and a second connecting groove 4932. The first connecting groove 4931 extends downward to the bottom silicon 4611 and partially hollows out the bottom silicon 4611. The second connecting groove 4932 extends horizontally to increase the hollowing range, thereby increasing the thermal isolation area.

[0304] The second thermal isolation portion 494 includes a third connecting groove 4941 and a fourth connecting groove 4942. The third connecting groove 4941 extends downward to the bottom silicon layer 4611, partially hollowing out the bottom silicon layer 4611. The fourth connecting groove 4942 extends horizontally to increase the hollowing range, thereby increasing the thermal isolation area.

[0305] Illustratively, the first connecting groove 4931 is formed by etching downward, and then etching is continued and the etching range is increased to form the second connecting groove 4932. Illustratively, the final shape of the first heat isolation portion 493 and the second heat isolation portion 494 can be irregular or regular.

[0306] In the present disclosure, a first thermal isolation portion 493 and a second thermal isolation portion 494 are formed in the Si-based platform to block the downward conduction path of the heat generated by the first heating portion 491 and the second heating portion 492, thereby limiting the heat to the vicinity of the first P-type InP region 466a and the second P-type InP region 466b, preventing the heat from being conducted downward, thereby improving the temperature regulation efficiency.

[0307] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. An optical module, characterized in that: include: circuit boards; A hybrid integrated optical chip is electrically connected to the circuit board and includes: optical modulators; A wave splitter is provided on one side of the optical modulator, and is used to output two paths of light to be modulated to the optical modulator respectively; A combiner, provided on the other side of the optical modulator, for combining the two optical modulated signals generated by the optical modulator; The optical modulator comprises, from bottom to top: The silicon waveguide layer has a silicon contraction region corresponding to receiving two paths of light to be modulated formed on one end facing the demultiplexer, and a silicon expansion region corresponding to coupling two paths of optical modulation signals formed on one end facing the combiner; The N-type InP layer has a first InP expansion region corresponding to coupling two paths of light to be modulated formed on one end of the splitter, and a first InP contraction region corresponding to coupling two paths of light modulation signals formed on one end of the combiner; The quantum well layer has a second InP expansion region corresponding to coupling two paths of light to be modulated formed on one end of the splitter, and a second InP contraction region corresponding to coupling two paths of light modulation signals formed on one end of the combiner; The P-type InP layer has a third InP expansion region corresponding to coupling two paths of light to be modulated formed on one end facing the splitter, and a third InP contraction region corresponding to coupling two paths of light modulation signals formed on one end facing the combiner; The silicon contraction region, the first InP expansion region, the second InP expansion region, and the third InP expansion region corresponding to a path of light to be modulated are sequentially stacked vertically to couple the light to be modulated in the silicon contraction region upward to the quantum well layer for signal modulation; The silicon expansion region, the first InP contraction region, the second InP contraction region, and the third InP contraction region corresponding to one optical modulation signal are stacked vertically in sequence to couple the optical modulation signal generated by the quantum well layer modulation downward to the silicon expansion region for output.

2. The optical module according to claim 1, wherein A silicon flat region is formed between the silicon contraction region and the corresponding silicon expansion region; A first InP flat region is formed between the first InP expansion region and the corresponding first InP contraction region; A second InP flat region is formed between the second InP expansion region and the corresponding second InP contraction region; A third InP flat region is formed between the third InP expansion region and the corresponding third InP contraction region; The silicon flat region, the first InP flat region, the second InP flat region, and the third InP flat region corresponding to one light path are stacked vertically in sequence to perform signal modulation in the second InP flat region.

3. The optical module according to claim 1, wherein: A second InP flat region is formed between the second InP expansion region and the corresponding second InP contraction region; the second InP flat region is used for signal modulation; Along the direction from the splitter to the combiner, the waveguide width of the silicon contraction region gradually narrows, and the waveguide widths of the first InP expansion region, the second InP expansion region, and the third InP expansion region gradually widen, so that a path of light to be modulated is coupled to the corresponding silicon contraction region, and then upwardly coupled from the silicon contraction region to the first InP expansion region in the corresponding N-type InP layer and the second InP expansion region in the quantum well layer, and then laterally coupled along the second InP expansion region to the second InP flat region, and signal modulation is performed in the second InP flat region; wherein the generated optical modulation signal is laterally coupled to the second InP contraction region; Along the direction from the splitter to the combiner, the waveguide width of the silicon expansion region gradually widens, and the waveguide widths of the first InP contraction region, the second InP contraction region, and the third InP contraction region gradually narrow, so that an optical modulated signal is sequentially coupled downward from the second InP contraction region to the first InP contraction region in the N-type InP layer and the silicon expansion region of the silicon waveguide layer, and is output along the silicon expansion region.

4. The optical module according to claim 1, wherein: The input end of the combiner is formed with a laser; The laser comprises a silicon waveguide layer at the bottom and an InP light emitting region above the silicon waveguide layer; A grating layer is formed on the upper surface of the silicon waveguide layer; The InP light-emitting area includes from bottom to top: N-type InP layer; stress limiting layer; N-InP ohmic contact layer, with an N-type electrode formed on the surface; quantum well layer; P-type InP layer; The P-InP ohmic contact layer has a P-type electrode formed on its surface.

5. The optical module according to claim 1, wherein: A first heating portion and a second heating portion are respectively formed on both sides of the P-type InP layer; A first heat insulating portion is formed on one side of the first heating portion, and a second heat insulating portion is formed on one side of the second heating portion.

6. An optical modulator, characterized in that From bottom to top they include: The silicon waveguide layer has a silicon contraction region at one end for receiving two paths of light to be modulated, and a silicon expansion region at the other end for coupling two paths of light modulation signals; An N-type InP layer, wherein a first InP expansion region corresponding to coupling two paths of light to be modulated is formed at one end, and a first InP contraction region corresponding to coupling two paths of light modulation signals is formed at the other end; The quantum well layer has a second InP expansion region corresponding to the coupling of two paths of light to be modulated formed at one end, and a second InP contraction region corresponding to the coupling of two paths of light modulation signals formed at the other end; A P-type InP layer, one end of which is respectively formed with a third InP expansion region corresponding to coupling two paths of light to be modulated, and the other end of which is respectively formed with a third InP contraction region corresponding to coupling two paths of light modulation signals; The silicon contraction region, the first InP expansion region, the second InP expansion region, and the third InP expansion region corresponding to a path of light to be modulated are sequentially stacked vertically to couple the light to be modulated in the silicon contraction region upward to the quantum well layer for signal modulation; The silicon expansion region, the first InP contraction region, the second InP contraction region, and the third InP contraction region corresponding to one optical modulation signal are stacked vertically in sequence to couple the optical modulation signal generated by the quantum well layer modulation downward to the silicon expansion region for output.

7. The optical modulator according to claim 6, wherein A silicon flat region is formed between the silicon contraction region and the corresponding silicon expansion region; A first InP flat region is formed between the first InP expansion region and the corresponding first InP contraction region; A second InP flat region is formed between the second InP expansion region and the corresponding second InP contraction region; A third InP flat region is formed between the third InP expansion region and the corresponding third InP contraction region; The silicon flat region, the first InP flat region, the second InP flat region, and the third InP flat region corresponding to one light path are stacked vertically in sequence to perform signal modulation in the second InP flat region.

8. The optical modulator according to claim 6, wherein A second InP flat region is formed between the second InP expansion region and the corresponding second InP contraction region; the second InP flat region is used for signal modulation; Along the direction from one end of the optical modulator to the other end, the waveguide width of the silicon contraction region gradually narrows, and the waveguide widths of the first InP expansion region, the second InP expansion region, and the third InP expansion region gradually widen, so that a path of light to be modulated is coupled to the corresponding silicon contraction region, and then upwardly coupled from the silicon contraction region to the first InP expansion region in the corresponding N-type InP layer and the second InP expansion region in the quantum well layer, and then laterally coupled along the second InP expansion region to the second InP flat region, and signal modulation is performed in the second InP flat region; wherein the generated optical modulated signal is laterally coupled to the second InP contraction region; Along the direction from one end of the optical modulator to the other end, the waveguide width of the silicon expansion region gradually widens, and the waveguide widths of the first InP contraction region, the second InP contraction region, and the third InP contraction region gradually narrow, so that an optical modulated signal is sequentially coupled downward from the second InP contraction region to the first InP contraction region in the N-type InP layer and the silicon expansion region of the silicon waveguide layer, and is output along the silicon expansion region.

9. The optical modulator according to claim 6, wherein The silicon waveguide layer comprises, from bottom to top,: underlying silicon; buried oxide layer; a first silicon ridge waveguide and a second silicon ridge waveguide respectively located on both sides of the upper surface of the buried oxide layer; The input end of the first silicon ridge waveguide is used for a channel of light to be modulated, and the output end is used for outputting a channel of optical modulation signal; The input end of the second silicon ridge waveguide is used to receive another path of light to be modulated, and the output end is used to output another path of optical modulated signal.

10. The optical modulator according to claim 7, wherein Along the direction from one end of the optical modulator to the other end, the optical modulator includes a first gradient coupling region, a light modulation region, and a second gradient coupling region; The first tapered coupling region includes, from bottom to top, the silicon contraction region, the first InP expansion region, the second InP expansion region, and the third InP expansion region; The light modulation area includes, from bottom to top, the silicon flat area, the first InP flat area, the second InP flat area, and the third InP flat area; The second tapered coupling region includes, from bottom to top, the silicon expansion region, the first InP contraction region, the second InP contraction region, and the third InP contraction region.

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