Laser, hybrid integrated optical chip and optical module

Abstract

The utility model provides a laser, a hybrid integrated optical chip and an optical module. The laser comprises a P-InP ohmic contact layer, a P-type InP layer, a quantum well layer, an N-InP ohmic contact layer, an N-type InP layer and a waveguide layer from top to bottom. Wherein the P-type InP layer provides P-type carriers for the quantum well layer, and the N-type InP layer provides N-type carriers for the quantum well layer. And the P-type carriers and the N-type carriers are compounded in the quantum well layer to generate light. The waveguide layer is located below the quantum well. The optical confinement factor of the waveguide layer is larger than the optical confinement factor of the quantum well layer, so that the light field in the quantum well layer is large, the light is downwards coupled into the waveguide layer, and then light is output through the waveguide layer. The laser provided by the embodiment of the utility model emits light downwards and then outputs the light horizontally. The laser provided by the embodiment of the utility model can be integrated in a silicon optical chip, so that light emitting and modulation are integrated in the same chip.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technology, and in particular to a laser, a hybrid integrated optical chip and an optical module. Background Art

[0002] With the development of new services and application models such as cloud computing, mobile Internet, and video, the advancement of optical communication technology has become increasingly important. In optical communication technology, optical modules, as one of the key components in optical communication equipment, can realize the conversion of optical and electrical signals. In the development of optical communication technology, the data transmission rate of optical modules is required to be continuously improved. Utility Model Content

[0003] The embodiments of the present disclosure provide a laser, a hybrid integrated optical chip and an optical module to improve the optical coupling efficiency.

[0004] In a first aspect, a laser provided in an embodiment of the present disclosure includes:

[0005] P-InP ohmic contact layer;

[0006] P-type InP layer, used for outputting P-type carriers;

[0007] A quantum well layer, used for receiving the P-type carriers;

[0008] N-InP ohmic contact layer;

[0009] An N-type InP layer is used to output N-type carriers to the quantum well layer, so that the N-type carriers and the P-type carriers are recombined in the quantum well layer to generate light;

[0010] A waveguide layer, wherein the optical confinement factor of the waveguide layer is greater than the optical confinement factor of the quantum well layer, so that the light field in the quantum well layer is coupled downwardly into the waveguide layer, and the light generated in the quantum well layer is output.

[0011] In a second aspect, the hybrid integrated optical chip provided by the embodiments of the present disclosure includes:

[0012] A laser, wherein the laser is the above-mentioned laser;

[0013] A wave splitter is arranged on the output optical path of the laser to receive the light output by the waveguide layer of the laser and split the light into two paths of light to be modulated;

[0014] An optical modulator is arranged on the output optical path of the splitter to receive two paths of light to be modulated and modulate the two paths of light to be modulated;

[0015] The combiner is arranged at one side of the optical modulator and is used for combining two optical modulation signals generated by the optical modulator.

[0016] In a third aspect, an optical module provided by an embodiment of the present disclosure includes:

[0017] Circuit boards;

[0018] A hybrid integrated optical chip is electrically connected to the circuit board, and the hybrid integrated optical chip is the hybrid integrated optical chip mentioned above.

[0019] In the laser, hybrid integrated optical chip and optical module provided by the embodiments of the present disclosure, the laser includes from top to bottom: a P-InP ohmic contact layer, a P-type InP layer, a quantum well layer, an N-InP ohmic contact layer, an N-type InP layer and a waveguide layer. Among them, the P-type InP layer provides P-type carriers to the quantum well layer, and the N-type InP layer provides N-type carriers to the quantum well layer. P-type carriers and N-type carriers recombine in the quantum well layer to generate light. The waveguide layer is located below the quantum well. The optical confinement factor of the waveguide layer is greater than the optical confinement factor of the quantum well layer, so the light field in the quantum well layer is larger, so that it is coupled downward into the waveguide layer, and then the light is output through the waveguide layer. In the laser provided by the embodiments of the present disclosure, the light generated by the quantum well layer is coupled downward into the waveguide layer, and then output along the waveguide layer. The light emission form of the laser provided by the embodiments of the present disclosure is downward emission and then horizontal output. The laser provided by the embodiments of the present disclosure can be integrated into a silicon photonics chip, so that light emission and modulation are integrated into the same chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0021] Figure 1 A partial architecture diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0022] Figure 2 A partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0023] Figure 3 A structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0024] Figure 4 An exploded view of an optical module provided according to some embodiments of the present disclosure;

[0025] Figure 5A schematic diagram of the internal structure of an optical module provided according to some embodiments of the present disclosure;

[0026] Figure 6 A schematic diagram of the internal structure of an optical chip provided according to some embodiments of the present disclosure;

[0027] Figure 7 A top view structure of a light modulator provided according to some embodiments of the present disclosure Figure 1 ;

[0028] Figure 8 A structural diagram of a silicon waveguide provided according to some embodiments of the present disclosure;

[0029] Fig. 9 A three-dimensional structural diagram of an optical modulator provided according to some embodiments of the present disclosure;

[0030] Fig.10 is a cross-sectional structural diagram of an optical modulator provided according to some embodiments of the present disclosure;

[0031] Fig.11 A top view structure of a light modulator provided according to some embodiments of the present disclosure Figure 2 ;

[0032] Fig.12 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 1 ;

[0033] Fig.13 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 2 ;

[0034] Fig.14 A schematic diagram of an optical path of an optical modulator provided according to some embodiments of the present disclosure;

[0035] Fig.15 A schematic diagram of a gradual change of a silicon waveguide provided according to some embodiments of the present disclosure;

[0036] Fig.16 A structural diagram of an N-type InP layer provided according to some embodiments of the present disclosure;

[0037] Fig.17 A structural diagram of a quantum well layer provided according to some embodiments of the present disclosure;

[0038] Fig.18 A structural diagram of a P-type InP layer provided according to some embodiments of the present disclosure;

[0039] Fig.19 A schematic diagram of the structure of a modulator integrated inside an optical chip according to some embodiments of the present disclosure;

[0040] Fig. 20 A schematic diagram of a cross-sectional structure of a laser provided according to some embodiments of the present disclosure;

[0041] Fig.21 A partial schematic diagram of a laser provided according to some embodiments of the present disclosure;

[0042] Fig. 22 This is a schematic diagram of the structure of a light modulator with an internally integrated heater according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0043] Some embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. However, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0044] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be interpreted as having an open, inclusive meaning, 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" implies open and inclusive language, which does not exclude devices that are suitable for or configured to perform additional tasks or steps; descriptions such as "parallel", "perpendicular", "same", "consistent", and "flush" are not limited to absolute mathematical theoretical relationships, but also include an acceptable error range generated in practice, and also include differences based on the same design concept but due to manufacturing reasons.

[0045] In optical communication technology, in order to establish information transmission between information processing devices, it is necessary to load information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When optical signals are transmitted in information transmission equipment, the loss of optical power can be reduced, so high-speed, long-distance, and low-cost information transmission can be achieved. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment usually includes optical network terminals (Optical Network Unit, ONU), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment usually includes optical fibers and optical waveguides.

[0046] The optical module can realize the mutual conversion between optical signals and electrical signals between information processing equipment and information transmission equipment. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected to an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected to an optical network terminal; the first optical signal from the optical fiber is transmitted to the optical module, and the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network terminal; the second electrical signal from the optical network terminal is transmitted to the optical module, and the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since multiple information processing devices can transmit information through electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, and all information processing devices do not need to be directly connected to the optical module. Here, the information processing device directly connected to the optical module is called the upper computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be called an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be called an electrical port.

[0047] 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 .

[0048] One end of the optical fiber 101 extends toward the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the total reflection direction can almost maintain the original optical power. The optical signal undergoes multiple total reflections in the optical fiber 101 to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance, low-power loss information transmission.

[0049] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 are 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 working state of the optical module 200.

[0050] 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 so that the host computer 100 and the optical module 200 establish a unidirectional or bidirectional electrical signal connection.

[0051] The host computer 100 also includes an external electrical interface, which can be connected to an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104, and the network cable interface 104 is configured to access the 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 as to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. For example, the third electrical signal sent by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, and the host computer 100 generates a second electrical signal according to the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200, and 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, and the second optical signal is transmitted to the remote information processing device 1000 in the optical fiber 101. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted to the optical module 200, and the optical module 200 converts the first optical signal into a first electrical signal, and the optical module 200 transmits the first electrical signal to the host computer 100, and the host computer 100 generates a fourth electrical signal according to the first electrical signal, and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that the optical module is a tool for realizing the mutual conversion between optical signals and electrical signals. During the conversion process between the optical signals and electrical signals, the information does not change, but the encoding and decoding methods of the information can change.

[0052] 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.

[0053] Figure 2 FIG. 1 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 circuit board 105 disposed in the housing, a cage 106 disposed on the surface of the PCB circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0054] The optical module 200 is inserted into the cage 106 of the host computer 100, and the cage 106 fixes the optical module 200. The heat generated by the optical module 200 is transferred to the cage 106 and then diffused through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 establishes a bidirectional electrical signal connection with the host computer 100. In addition, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101.

[0055] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure, Figure 4 FIG. 1 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 shell, a circuit board 300 disposed in the shell, 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, respectively, 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.

[0056] The housing comprises 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 body.

[0057] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicular to the bottom 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.

[0058] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and vertically arranged with the bottom 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 vertically arranged with the cover plate 2011, and the two upper side plates are combined with the two lower side plates 2022 to realize that the upper shell 201 covers the lower shell 202.

[0059] 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, the opening 204 is located at the end of the optical module 200, and the opening 205 is located at the side of the optical module 200. The opening 204 is an electrical port, and the gold finger 301 of the circuit board 300 extends from the opening 204 and is inserted into the electrical connector of the host computer 100; the opening 205 is an optical port, which is configured to access the external optical fiber 101 so that the optical fiber 101 is connected to the optical chip 400 in the optical module 200.

[0060] The upper housing 201 and the lower housing 202 are combined to facilitate the installation of the circuit board 300, the optical modulation chip, the light source, etc. into the housing, and the upper housing 201 and the lower housing 202 can encapsulate and protect the above components. In addition, when assembling the circuit board 300, the optical chip 400, the light source, etc., it is convenient to deploy the positioning components, heat dissipation components, and electromagnetic shielding components of these components, which is conducive to automated production.

[0061] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials to facilitate electromagnetic shielding and heat dissipation.

[0062] 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.

[0063] For example, the unlocking component 600 is located on the outside of the two lower side plates 2022 of the lower housing 202, and includes a snap-fit ​​component that matches 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 fixes 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 relationship between the snap-fit ​​component and the host computer, so as to release the fixation of the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0064] The circuit board 300 includes circuit traces, electronic components and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize the functions of power supply, electrical signal transmission and grounding. The electronic components may include capacitors, resistors, transistors, metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET). The chip may include a microcontroller unit (Microcontroller Unit, MCU), a laser driver chip, a transimpedance amplifier (Transimpedance Amplifier, TIA), a limiting amplifier (Limiting Amplifier, LA), a clock and data recovery chip (Clock and Data Recovery, CDR), a power management chip, and a digital signal processing (Digital Signal Processing, DSP) chip.

[0065] 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.

[0066] The circuit board 300 also 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 upper surface shown in the figure) can also be set on the upper and lower surfaces of the circuit board 300 to provide more pins, so as to adapt to occasions where the number of pins is large. The gold finger 301 is configured to establish an electrical connection with the host computer to achieve power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, etc. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement rigid circuit boards.

[0067] Figure 5 FIG. 1 is a 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 the optical signal: 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.

[0068] 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 a desired function.

[0069] Exemplarily, the monolithic integrated optical chip can be a silicon optical chip. Silicon material is easy to etch, and functional devices can be integrated inside the silicon optical chip, which has good integration. Exemplarily, a beam splitter, a light combiner, a mixer, a photodetector, etc. can be integrated inside the silicon optical chip. As an indirect bandgap semiconductor material, silicon does not have a linear electro-optic effect, but only a weak second-order electro-optic effect, resulting in a low modulation rate of the silicon optical chip.

[0070] Exemplarily, the monolithic integrated optical chip can be a thin-film lithium niobate chip. Thin-film lithium niobate has a linear electro-optical effect. An applied electric field causes a linear change in the refractive index in the corresponding direction, so that the light wave transmitted in the medium has adjustable intensity, phase and other information. Therefore, thin-film lithium niobate can be selected as the material of the optical modulator to achieve a higher modulation rate, etc. Thin-film lithium niobate materials are relatively hard and difficult to etch, making it difficult to integrate multiple functional devices on their surface. At the same time, the optical loss of thin-film lithium niobate chips is low.

[0071] In some embodiments, the optical chip 400 may be a hybrid integrated optical chip. Hybrid integration refers to manufacturing optical devices on different substrates according to the advantages of their respective material systems and the characteristics of the manufacturing process, and then integrating them together. The advantage of hybrid integration is that it can give full play to the excellent performance of different material systems.

[0072] Exemplarily, 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. The 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 the refractive index changes are caused to achieve optical signal modulation. The growth material system of the spectrometer, combiner, mixer, photodetector, 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.

[0073] Exemplarily, the hybrid integrated optical chip may be a thin-film lithium niobate / Si hybrid integrated optical chip. Compared with the 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.

[0074] The following embodiments are illustrative in detail by taking the optical chip 400 as an InP / Si hybrid integrated optical chip as an example.

[0075] In InP / Si hybrid integrated optical chips, since Si is an indirect bandgap semiconductor material, its luminescence efficiency is extremely low.

[0076] 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, and the external light source 500 emits light from the side and is coupled into the optical chip 400. The light emitted by the external light source 500 is light that does not carry data. After entering the optical chip 400, the optical chip 400 performs phase modulation on it to load the electrical signal into the light, obtain light that carries data, that is, generate an optical transmission signal, thereby realizing the transmission of the optical signal.

[0077] In some embodiments, the light source of the InP / Si hybrid integrated optical chip can also be an internal integrated light source. Group III-V is a direct bandgap semiconductor material with strong gain characteristics, so Group III-V has good light-emitting characteristics, such as InP lasers. Then the InP laser is integrated inside the InP / Si hybrid integrated optical chip.

[0078] 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 .

[0079] 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 a beam splitter 410 integrated inside the optical chip 400.

[0080] 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.

[0081] The second light beam is used as a light source of the optical transmission signal and is transmitted to the polarization beam splitter 430. The second light beam is split by the polarization beam splitter 430 into two light beams with different polarization directions: TE polarized light and TM polarized light.

[0082] The TE polarized light is split into two beams by the beam splitter 450, and the two beams are coupled to Figure 6 In the two optical modulators 460 located at the upper side. Of the two optical modulators 460, the optical modulator 460 located at the upper side performs I modulation on the received light to generate an I modulation signal; the optical modulator 460 located at the lower side performs Q modulation on the received light to generate a Q modulation signal. The I modulation signal and the Q modulation signal of the light beam are combined by the combiner 471 to generate a first modulated optical signal.

[0083] The TM polarized light is split into two beams by the beam splitter 440, and the two beams are coupled to Figure 6 In the two optical modulators 460 located at the lower side. Of the two optical modulators 460, the optical modulator 460 located at the upper side performs I modulation on the received light to generate an I modulation signal; the optical modulator 460 located at the lower side performs Q modulation on the received light to generate a Q modulation signal. The I modulation signal and the Q modulation signal of the light beam are combined by the combiner 472 to generate a second modulated optical signal.

[0084] The first modulated optical signal and the second modulated optical signal are combined by the combiner 473 to generate an optical transmission signal, thereby completing optical signal modulation.

[0085] The following embodiment uses one of the light modulators 460, such as Figure 6 The range enclosed by the middle ellipse is taken as an example for illustration.

[0086] Figure 7 A top view structure of a light 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 .

[0087] In some embodiments, the wavelength splitter 710 is disposed at one side of the optical modulator 460 to output two paths of light to be modulated to the optical modulator 460 respectively.

[0088] In some embodiments, the combiner 720 is disposed at the other side of the optical modulator 460 to combine two optical modulation signals generated by the optical modulator 460 .

[0089] In some embodiments, the optical modulator 460 is an InP-based Mach-Zehnder (MZ) modulator. The MZ modulator modulates the phase by changing the refractive index of the material, and then indirectly achieves light intensity modulation by using the principle of constructive and destructive interference of light. Compared with electro-absorption modulators (EAM) and electro-absorption modulated lasers (EML), the MZ modulator has a higher modulation rate and modulation efficiency.

[0090] The incident light of the MZ modulator is split into two paths by the splitter 710, and phase modulation is performed on one of the paths or both paths at the same time 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.

[0091] In some embodiments, due to the low transmission loss of silicon waveguide, the optical waveguide in the InP / Si hybrid integrated optical chip adopts silicon waveguide.

[0092] For one optical modulator 460, the silicon waveguide includes a silicon waveguide between the output end of the splitter 710 and the input end of the optical modulator 460, a silicon waveguide of the optical modulator 460 itself, and a silicon waveguide between the output end of the optical modulator 460 and the input end of the combiner 720. The three waveguide parts are sequentially connected to form a silicon waveguide as a whole.

[0093] The incident light of the MZ modulator is divided into two paths by the splitter 710, and the splitter 710 has two output ends. The optical modulator 460 has two input ends and two output ends. The input end and the output end of the optical modulator 460 are respectively located on the silicon waveguide of the optical modulator 460 itself.

[0094] In some embodiments, the silicon waveguide between the first output terminal of the splitter 710 and the first input terminal of the optical modulator 460 is called silicon waveguide 810. The silicon waveguide after the first output terminal of the optical modulator 460 is called silicon waveguide 820. Silicon waveguide 810 and silicon waveguide 820 correspond to one optical signal output by the splitter 710.

[0095] The silicon waveguide between the second output terminal of the splitter 710 and the second input terminal of the optical modulator 460 is called silicon waveguide 830. The silicon waveguide after the second output terminal of the optical modulator 460 is called silicon waveguide 840. Silicon waveguide 830 and silicon waveguide 840 correspond to another optical signal output by the splitter 710.

[0096] 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 .

[0097] In some embodiments, the silicon waveguide between the first input end and the first output end of the optical modulator 460 is a first silicon ridge waveguide 4613. The silicon waveguide section adopts a ridge waveguide based on the fact that the ridge waveguide has a higher modulation rate and modulation efficiency. The first silicon ridge waveguide 4613 corresponds to an optical signal output by the splitter 710.

[0098] The silicon waveguide between the second input end and the second output end of the optical modulator 460 is a second silicon ridge waveguide 4614. The silicon waveguide section adopts a ridge waveguide also based on the high modulation rate and modulation efficiency of the ridge waveguide. The second silicon ridge waveguide 4614 corresponds to another optical signal output by the splitter 710.

[0099] 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.

[0100] 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.

[0101] 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; and the output end is connected to the silicon waveguide 840 to output the optical modulation signal generated by the modulation.

[0102] 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.

[0103] 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.

[0104] The quantum well layer 465 is a target layer for the light to be modulated to reach, so as to realize modulation in the quantum well layer 465. By controlling the change of the external electric field, the carrier changes, so that the refractive index of the quantum well layer 465 changes, so as to realize signal modulation.

[0105] The quantum well layer 465 is located between the N-type InP layer 462 and the P-type InP layer 466. The light field is confined within the quantum well layer 465 by the N-type InP layer 462 and the P-type InP layer 466 disposed up and down, so as to avoid the light field from diverging.

[0106] 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.

[0107] 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 .

[0108] In some embodiments, the incident light of the MZ modulator is split into two paths by the wavelength splitter 710 .

[0109] One of the light signals to be modulated is coupled to the input end of the first silicon ridge waveguide 4613 along the silicon waveguide 810, and the light signal to be modulated transmitted in the first silicon ridge waveguide 4613 is coupled upward to the quantum well layer 465 for modulation. The modulated optical signal is coupled downward to the output end of the first silicon ridge waveguide 4613, and then transmitted to the combiner 720 along the first silicon ridge waveguide 4613 and the silicon waveguide 820 in sequence.

[0110] Another path of light to be modulated is coupled to the input end of the second silicon ridge waveguide 4614 along the silicon waveguide 830, and the light to be modulated transmitted in the second silicon ridge waveguide 4614 is coupled upward to the quantum well layer 465 for modulation. The modulated optical signal is coupled downward to the second silicon ridge waveguide 4614, and then transmitted to the combiner 720 along the second silicon ridge waveguide 4614 and the silicon waveguide 840 in sequence.

[0111] The two modulated optical signals are respectively connected to the combiner 720, combined into one optical signal and output.

[0112] 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.

[0113] When the silicon waveguide adopts a ridge structure, it includes 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.

[0114] 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 end and the first output end of the optical modulator 460; silicon waveguide 830 and silicon waveguide 840 are respectively connected to the second input end and the second output end of the optical modulator 460.

[0115] 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 coupled upward to the InP modulation region respectively, 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.

[0116] A silicon waveguide 810 is provided between the first output end of the splitter 710 and the first input end of the optical modulator 460 to couple the split 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 and generated in the optical modulator 460.

[0117] A silicon waveguide 830 is provided between the second output end of the splitter 710 and the second input end of the optical modulator 460 to couple the other path of light after the splitting 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 optical signal modulated and generated in the optical modulator 460.

[0118] One light path output by the splitter 710 is transmitted along the silicon waveguide 810 to the input end of the first silicon ridge waveguide 4613, and then the light path is coupled upward to the light modulation area of ​​the optical modulator 460 for signal modulation. The modulated optical signal is coupled downward back to the output end of the first silicon ridge waveguide 4613, and continues to be transmitted along the silicon waveguide 820 to be connected to the combiner 720.

[0119] Another path of light outputted by the splitter 710 is transmitted along the silicon waveguide 830 to the input end of the second silicon ridge waveguide 4614, and then the light is coupled upward to the optical modulation area of ​​the optical modulator 460 for signal modulation. The modulated optical signal is coupled downward back to the output end of the second silicon ridge waveguide 4614, and continues to be transmitted along the silicon waveguide 840 to be connected to the combiner 720.

[0120] The two modulated optical signals are respectively connected to the combiner 720, combined into one optical signal and output.

[0121] Fig. 9 A three-dimensional structural diagram of an optical modulator provided according to some embodiments of the present disclosure; Fig.10 FIG. 1 is a cross-sectional structural diagram of an optical modulator provided according to some embodiments of the present disclosure. Fig. 9 and Fig.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 .

[0122] In some embodiments, the optical modulator 460 is an InP / Si hybrid integrated optical modulator.

[0123] The optical modulator 460 may include a silicon waveguide layer 461 at the bottom. The silicon waveguide layer 461 is a silicon waveguide of the optical modulator 460 itself, so as to fully utilize the advantage of low transmission loss of the silicon waveguide.

[0124] 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.

[0125] In some embodiments, the silicon waveguide layer 461 is formed of silicon-on-insulator (SOI).

[0126] In some embodiments, the SOI waveguide includes: a bottom silicon 4611, a buried oxide layer 4612 located on the upper surface of the bottom silicon 4611, and a first silicon ridge waveguide 4613 and a second silicon ridge waveguide 4614 respectively located on both sides 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 avoid mutual coupling between the two paths of light to be modulated.

[0127] Exemplarily, the bottom silicon 4611 is a substrate layer.

[0128] Exemplarily, the buried oxide layer 4612 is a SiO2 layer. Since there is a large refractive index difference between silicon and SiO2, the SOI silicon waveguide has a strong light field confinement capability, and the SOI silicon waveguide has a low light transmission loss.

[0129] Exemplarily, the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 are transmission layers for the two paths of light, respectively. Based on the low transmission loss of the ridge waveguide, a ridge waveguide structure is adopted in the present disclosure. It is understandable that a non-ridge waveguide structure may also be adopted in some embodiments.

[0130] In some embodiments, the incident light of the MZ modulator is split into two paths by a wave splitter 710 at the input end.

[0131] The first output end of the splitter 710 is connected to the input end of the first silicon ridge waveguide 4613 through the silicon waveguide 810 to receive a light path output by the splitter 710 and couple it to the first silicon ridge waveguide 4613 .

[0132] The second output end of the splitter 710 is connected to the input end of the second silicon ridge waveguide 4614 through a silicon waveguide 830 to receive another path of light output by the splitter 710 and couple it into the second silicon ridge waveguide 4614 .

[0133] 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 downwardly coupled back to the output ends of the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614. Then, the two paths of light 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 light signal and output.

[0134] In some embodiments, the InP modulation region includes, from bottom to top:

[0135] N-type InP layer 462, located on the upper surface of the silicon waveguide layer 461;

[0136] stress limiting layer 463;

[0137] N-InP ohmic contact layer 464;

[0138] quantum well layer 465;

[0139] P-type InP layer 466;

[0140] P-InP ohmic contact layer 467 .

[0141] In some embodiments, the N-type InP layer 462 is an N-type doped semiconductor, such as doped with a pentavalent element.

[0142] The P-type InP layer 466 is a P-type doped semiconductor, such as doped with a trivalent element.

[0143] The N-type InP layer 462 and the P-type InP layer 466 are doped with different impurity elements to form a PN junction.

[0144] When no forward bias voltage is applied to the PN junction, the above carrier movement is in a balanced state. When a forward bias voltage is applied to the PN junction, the carrier movement balance state will be destroyed, thereby forming a conduction current. The formed conduction current is applied to the quantum well layer 465.

[0145] 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.

[0146] There is a depletion region at the junction of the P region and the N region in the PN junction. The depletion region of the PN junction is narrow, and the carriers contain diffusion components, which seriously affects the modulation rate. By setting the i-InP intrinsic layer 468 in the middle of the PN junction, the width of the depletion region is increased, so that the carriers drift to the PN junction under the action of a strong electric field, avoiding the influence of the carrier diffusion component on the optical modulator 460, thereby improving the modulation rate.

[0147] In some embodiments, the growth material of the silicon waveguide layer 461 is silicon, and the InP modulation region is an InP region. The lattice constants of the silicon material and the InP semiconductor material are quite different, and there is a large lattice mismatch between the two, which results in stress when the InP material is epitaxially grown on silicon. The stress limiting layer 463 can limit the stress between the silicon material and the InP semiconductor material within the layer, preventing the stress from being transmitted upward to the quantum well layer 465, so as to protect the quantum well layer 465.

[0148] In some embodiments, the quantum well layer 465 is an active region, and the quantum well layer 465 is a target layer for the light to be modulated to achieve modulation in the quantum well layer 465. The refractive index of the quantum well material is relatively large, and the optical signal can be well confined in the quantum well layer 465 in the longitudinal direction.

[0149] By controlling the change of the external electric field, the carrier changes, thereby changing the refractive index of the quantum well layer 465. Since the change in the refractive index of the quantum well layer 465 is proportional to the phase change between the two modulation arms of the optical modulator 460, the phase difference between the two modulation arms can be adjusted by adjusting the refractive index of the quantum well layer 465.

[0150] The output light intensity varies with the phase difference between the two modulation arms, that is, the output light intensity is modulated by the modulated electrical signal. The modulated electrical signal is modulated and becomes the output light intensity of the modulated optical signal, thereby achieving modulation.

[0151] 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 to the quantum well layer 465. After completing the 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.

[0152] In some embodiments, in the InP modulation region, the area above the first silicon ridge waveguide 4613 corresponding to the first modulation arm 462a of the optical modulator 460 , and the area above the second silicon ridge waveguide 4614 corresponding to the second modulation arm 462b of the optical modulator 460 .

[0153] 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.

[0154] 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 up and down, 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 upwards and does not exceed the N-type InP layer 462 downwards, thereby constraining the light field and avoiding light field divergence, thereby increasing the optical coupling efficiency.

[0155] 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 in 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 first modulation partition above and below, and a second P-type InP region 466b corresponding to the second modulation partition above and below.

[0156] The first P-type InP region 466a and the second P-type InP region 466b protrude relative to the quantum well layer 465, presenting 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.

[0157] In some embodiments, a P-type electrode 4671 is disposed on the surface of the P-InP ohmic contact layer 467 in the first P-type InP region 466a, and a P-type electrode 4671 is disposed on the surface of the P-InP ohmic contact layer 467 in the second P-type InP region 466b.

[0158] The width of the N-InP ohmic contact layer 464 is greater than the width of the quantum well layer 465 , so that gaps are left at both ends of the N-InP ohmic contact layer 464 relative to the ends of the quantum well layer 465 , and N-type electrodes 4641 can be formed at both ends of the N-InP ohmic contact layer 464 .

[0159] 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.

[0160] The growth material of the silicon waveguide layer 461 is silicon, and the InP modulation region is an InP region. The lattice constants of the silicon material and the InP semiconductor material are quite different, and there is a large lattice mismatch between the two, which leads to stress when the InP material is epitaxially grown on silicon, and thus the quality of hybrid integration is poor. For this reason, an intermediate bonding layer 469 is provided between the silicon waveguide layer 461 and the InP modulation region.

[0161] 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 forces 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.

[0162] Exemplarily, the middle bonding layer 469 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.

[0163] 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.

[0164] Silicon waveguide and InP waveguide are waveguides made of different materials, and their optical field modes are different. Therefore, when light is coupled between silicon waveguide and InP waveguide, there is a large mode mutation and mode field mismatch, resulting in large coupling loss.

[0165] Exemplarily, 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 modulated 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.

[0166] Fig.11 A top view of a light modulator 460 provided according to some embodiments of the present disclosure Figure 2 .like Fig.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 .

[0167] In some embodiments, in order to increase the optical confinement effect of the P-type InP layer 466, the two 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 light fields to be modulated, respectively, as shown in FIG. Fig.11 The first P-type InP region 466a and the second P-type InP region 466b are shown.

[0168] In the present disclosure, each layer of waveguide of the optical modulator 460 toward the splitter 710 and the end 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 mutation 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.

[0169] In the coupling region at one end of the optical modulator 460, i.e., toward the end of the splitter 710, the waveguide widths of the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 gradually narrow, and the waveguide widths of each layer of the InP region gradually widen, 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. When the refractive index of the silicon ridge waveguide is the same as the refractive index of the InP region waveguide at a certain moment, the maximum light coupling efficiency is generated.

[0170] In the coupling region at the other end of the optical modulator 460, i.e., the end toward the combiner 720, the waveguide widths of the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 gradually widen, and the waveguide widths of each layer of the InP region gradually narrow, thereby squeezing the InP region waveguide light field energy into the silicon ridge waveguide, and more modulated light field energy is coupled downward into the silicon ridge waveguide for output. When the refractive index of the silicon ridge waveguide is the same as the refractive index of the InP region waveguide at a certain moment, the maximum light coupling efficiency is generated.

[0171] 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 in the coupling region for modulation.

[0172] For the convenience of description, the end of the optical modulator 460 facing the wave splitter 710 is called the first end, and the end of the optical modulator 460 facing the wave combiner 720 is called the second end. The coupling region corresponding to the first end is called the first gradual coupling region 460a, and the coupling region corresponding to the second end is called the second gradual coupling region 460c.

[0173] 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 limit the light field, and increasing the ability of the InP waveguide to limit 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.

[0174] 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 limit the light field, and increasing the ability of the silicon ridge waveguide to limit the light field, so that the modulated light field of the InP modulation region in the second gradient coupling region 460c can be squeezed into the silicon ridge waveguide to output a modulated light signal.

[0175] The waveguide layers at both ends of the optical modulator 460 are respectively formed with a gradient structure, 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.

[0176] Fig.12 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 1 ; Fig.13 A layered structure of an optical modulator provided according to some embodiments of the present disclosure Figure 2 .like Fig.12 and Fig.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.

[0177] In some embodiments, the waveguide width of the N-type InP layer 462 is relatively large to provide better support.

[0178] In some embodiments, the incident light of the MZ modulator is split into two paths by the splitter 710, and the splitter 710 has two output ends. The optical modulator 460 correspondingly has two input ends and two output ends.

[0179] In some embodiments, the silicon waveguide layer 461 has a silicon contraction region 4615 corresponding to receiving two modulated lights at one end facing the demultiplexer 710 , and has a silicon expansion region 4616 corresponding to coupling two optical modulation signals at one end facing the combiner 720 .

[0180] In some embodiments, the N-type InP layer 462 has a first InP expansion region 4621 corresponding to coupling two light beams to be modulated formed at one end facing the demultiplexer 710 , and a first InP contraction region 4623 corresponding to coupling two light modulation signals formed at one end facing the combiner 720 .

[0181] In some embodiments, the quantum well layer 465 has a second InP expansion region 4651 corresponding to coupling two light beams to be modulated formed at one end thereof facing the demultiplexer 710, and a second InP contraction region 4653 corresponding to coupling two light modulation signals formed at one end thereof facing the combiner 720.

[0182] In some embodiments, the P-type InP layer 466 has a third InP expansion region 4661 corresponding to coupling two light beams to be modulated formed at one end facing the demultiplexer 710, and a third InP contraction region 4663 corresponding to coupling two light modulation signals formed at one end facing the combiner 720.

[0183] 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.

[0184] 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.

[0185] In some embodiments, the first silicon ridge waveguide 4613 and the second silicon ridge waveguide 4614 have the same structure. As described above, the silicon ridge waveguide includes 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 for exemplary description.

[0186] In some embodiments, in order to increase the coupling efficiency between the silicon waveguide and the InP waveguide, the input end of the first silicon ridge waveguide 4613 has a silicon contraction region 4615, the output end has a silicon expansion region 4616, and there is a silicon flat region 4617 in the middle.

[0187] The N-type InP layer 462 includes two symmetrical partitions to couple two optical signals respectively. The two symmetrical partitions have the same structure. In the N-type InP layer 462, the corresponding ends of the two optical paths are: the end facing the splitter 710 has a first InP expansion area 4621, the end facing the combiner 720 has a first InP contraction area 4623, and the middle has a first InP flat area 4622.

[0188] The quantum well layer 465 is used to modulate the two optical signals respectively. 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 respectively. 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 optical 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.

[0189] In the P-type InP layer 466 , the corresponding ends of the two light paths have: an end facing the demultiplexer 710 has a third InP expansion region 4661 , an end facing the combiner 720 has a third InP contraction region 4663 , and a third InP flat region 4662 in the middle.

[0190] The above-mentioned “contraction” means that the waveguide width gradually narrows along the direction from the splitter 710 to the combiner 720. The above-mentioned “expansion” means that the waveguide width gradually widens along the direction from the splitter 710 to the combiner 720. The meanings of the above-mentioned contraction areas and expansion areas all fall within this interpretation range.

[0191] In the coupling region of the optical modulator 460 toward the splitter 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.

[0192] 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.

[0193] In the middle region of the optical modulator 460 , the silicon flat region 4617 , the first InP flat region 4622 , the second InP flat region 4652 , and the third InP flat region 4662 are stacked vertically in sequence.

[0194] 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.

[0195] In some embodiments, the first gradient 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.

[0196] In the first gradual coupling region 460a, the width of the silicon waveguide gradually narrows, and then 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.

[0197] The first InP expansion region 4621, the second InP expansion region 4651, and the third InP expansion region 4661 are waveguide structures of each layer of the InP region. In the first gradient coupling region 460a, the width of each layer of the waveguide in the InP region gradually widens, and then the effective refractive index of each layer of the waveguide in the InP region gradually increases, and the ability to limit light waves gradually increases, so that the light field is squeezed from the silicon waveguide to the InP region in the first gradient coupling region 460a to perform signal modulation.

[0198] 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 between the silicon waveguide and the InP waveguide of the light to be modulated, and realizing low-loss coupling in the coupling region.

[0199] In some embodiments, the second gradient 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 .

[0200] In the second gradual coupling region 460c, the width of the silicon waveguide gradually widens, and then the effective refractive index of the silicon waveguide at the output end gradually increases, and the ability to limit light waves gradually increases.

[0201] The first InP contraction region 4623, the second InP contraction region 4653, and the third InP contraction region 4663 are waveguide structures of each layer of the InP region. In the second gradient coupling region 460c, the width of each layer of the waveguide in the InP region gradually narrows, and then the effective refractive index of each layer of the waveguide in the InP region gradually decreases, and the ability to restrict light waves gradually weakens, so that the light field is squeezed from the InP region to the silicon waveguide in the second gradient coupling region 460c to transmit the optical modulation signal generated by the modulation.

[0202] In the present disclosure, in the second gradient coupling region 460c of the optical modulator 460, each waveguide is provided with a gradient structure, thereby reducing the mode mutation of the optical modulation signal between the silicon waveguide and the InP waveguide, and realizing low-loss coupling in the coupling region.

[0203] Fig.14 FIG. 1 is a schematic diagram of an optical path of an optical modulator provided according to some embodiments of the present disclosure. Fig.14 As shown, the optical path is exemplarily described below by taking an optical signal output by the splitter 710 as an example.

[0204] The silicon flat region 4617, the first InP flat region 4622, the second InP flat region 4652, and the third InP flat region 4662 stacked vertically constitute the light modulation region 460b of the light modulator 460. Among them, the second InP flat region 4652 is a structure that substantially performs signal modulation.

[0205] 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 in a vertical direction constitute a first gradual coupling region 460 a .

[0206] 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 in a vertical direction constitute a second gradual coupling region 460 c .

[0207] By providing a first gradual coupling region 460a at one end facing the splitter 710, more light field energy to be modulated is transferred from the silicon waveguide to the InP region for modulation.

[0208] By providing a second tapered coupling region 460 c at one end facing the combiner 720 , more modulated optical field energy can be released from the InP region into the silicon waveguide.

[0209] The light modulation region 460b of the light modulator 460 is in a flat state without any gradient, so as to ensure that the energy is maintained within this region.

[0210] The first gradient coupling region 460a is used to couple the light to be modulated upward to the light modulation region 460b.

[0211] The second gradient coupling region 460c is used to couple the optical modulation signal downward from the optical modulation region 460b.

[0212] 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 from the silicon waveguide to the second InP flat region 4652 for signal modulation to generate an optical modulation signal.

[0213] 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.

[0214] In some embodiments, an optical signal output by the splitter 710 enters the silicon contraction region 4615 along the silicon waveguide 810, is coupled upward to the first InP expansion region 4621 and the second InP expansion region 4651 in sequence, and is then 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.

[0215] The optical modulation signal is laterally coupled from the second InP flat region 4652 to the second InP contraction region 4653 of the same layer. The optical modulation signal is sequentially coupled downward from the second InP contraction region 4653 to the first InP contraction region 4623 and the silicon expansion region 4616, and then enters the silicon waveguide 820 of the same layer as the silicon expansion region 4616, so as to output the optical modulation signal along the silicon waveguide 820.

[0216] It is understandable that, in some embodiments, the first gradient coupling region 460 a of the optical modulator 460 may also 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 .

[0217] 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 disposed at one end of the optical modulator 460 facing the combiner 720 .

[0218] The structures of these two separate couplers are the same as the structure of the optical modulator 460 , except that the two couplers are passive devices and do not require P-type electrodes and N-type electrodes.

[0219] Fig.15 FIG. 1 is a schematic diagram of a gradual change of a silicon waveguide according to some embodiments of the present disclosure. Fig.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 .

[0220] 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 at the silicon flat region 4617 is the narrowest.

[0221] 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.

[0222] Fig.16 FIG. 1 is a structural diagram of an N-type InP layer provided according to some embodiments of the present disclosure. Fig.16 As shown, in some embodiments, both ends of the N-type InP layer 462 have a gradient structure.

[0223] The N-type InP layer 462 includes two symmetrical partitions with the same structure to transmit two optical signals respectively.

[0224] In the N-type InP layer 462 , the corresponding ends of the two light paths have a first InP expansion region 4621 at one end facing the demultiplexer 710 , a first InP contraction region 4623 at one end facing the combiner 720 , and a first InP flat region 4622 in the middle.

[0225] The first InP expansion region 4621 is used to attract the light field to be modulated 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.

[0226] Fig.17 FIG. 1 is a structural diagram of a quantum well layer provided according to some embodiments of the present disclosure. Fig.17 As shown, in some embodiments, the input end and the output end of the quantum well layer 465 have a gradient structure respectively.

[0227] 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.

[0228] In the quantum well layer 465 , the corresponding ends of the two light paths have: an end facing the demultiplexer 710 has a second InP expansion region 4651 , an end facing the combiner 720 has a second InP contraction region 4653 , and a second InP flat region 4652 in the middle.

[0229] 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.

[0230] The second InP expansion region 4651 is used to attract the light field to be modulated 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.

[0231] Fig.18 FIG. 1 is a structural diagram of a P-type InP layer provided according to some embodiments of the present disclosure. Fig.18 As shown, in some embodiments, in the P-type InP layer 466, the corresponding ends of the two light paths have: an end toward the splitter 710 has a third InP expansion region 4661, an end toward the combiner 720 has a third InP contraction region 4663, and a third InP flat region 4662 in the middle.

[0232] The third InP expansion region 4661 is used to attract the light field to be modulated 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.

[0233] In the present disclosure, as mentioned above, the light source of the InP / Si hybrid integrated optical chip can also be an internal integrated light source. Group III-V is a direct bandgap semiconductor material with strong gain characteristics, so Group III-V has good light-emitting characteristics, such as InP lasers. Then the InP laser is integrated inside the InP / Si hybrid integrated optical chip.

[0234] Fig.19 FIG. 1 is a schematic diagram of a structure of a modulator integrated inside an optical chip according to some embodiments of the present disclosure. Fig.19 As shown, a laser 480 is integrated inside the optical chip 400. By way of example, the laser 480 is an InP laser.

[0235] The laser 480 is integrated in the optical chip 400, and the laser light outputted by the laser 480 is transmitted to the optical modulator 460 for signal modulation. The two ends of the optical modulator 460 may respectively form the first gradient coupling region 460a and the second gradient coupling region 460c.

[0236] The light output by the laser 480 is transmitted to the splitter 710. The two paths of light output by the splitter 710 are respectively coupled to the optical modulator 460 for signal modulation. The two paths of optical signals generated after modulation are coupled to the combiner 720. A beam of optical modulated signal is combined in the combiner 720 and output.

[0237] The optical chip 400 integrates a laser 480 and an optical modulator 460, thereby having both light emission and signal modulation functions, and completing light emission and signal modulation in the same chip.

[0238] In the present disclosure, the lasers corresponding to each channel are integrated into the hybrid integrated optical chip to increase integration. At the same time, each channel corresponds to a laser, which can reduce local power density and thermal stress, thereby improving the reliability of the hybrid integrated optical chip, making it suitable for multi-channel transmission.

[0239] Fig. 20 A schematic diagram of a cross-sectional structure of a laser provided according to some embodiments of the present disclosure; Fig.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 the same as the materials used to grow the layers of the laser 480 .

[0240] In some embodiments, laser 480 is an InP / Si hybrid integrated laser.

[0241] In some embodiments, the laser 480 may include a waveguide layer at the bottom. Exemplarily, the waveguide layer is a silicon waveguide layer 481, and the silicon waveguide layer 481 is a silicon waveguide of the laser 480 itself, so as to fully utilize the advantage of low transmission loss of silicon waveguide.

[0242] 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.

[0243] In some embodiments, the silicon waveguide layer 481 is formed of silicon-on-insulator (SOI).

[0244] In some embodiments, the SOI waveguide includes: an underlying silicon 4811 , a buried oxide layer 4812 located on the upper surface of the underlying silicon 4811 , and a silicon ridge waveguide 4813 located on the upper surface of the buried oxide layer 4812 .

[0245] Illustratively, the bottom silicon 4811 is a substrate layer.

[0246] Exemplarily, the buried oxide layer 4812 is a SiO2 layer. Since there is a large refractive index difference between silicon and SiO2, the SOI silicon waveguide has a strong light field confinement capability, and the SOI silicon waveguide has low light transmission loss.

[0247] Based on the low transmission loss of ridge waveguide, the present disclosure adopts a ridge waveguide structure. It can be understood that a non-ridge waveguide structure can also be used in some embodiments.

[0248] In some embodiments, the InP light emitting region includes, from bottom to top:

[0249] N-type InP layer 482, located on the upper surface of the silicon waveguide layer 481;

[0250] stress limiting layer 483;

[0251] N-InP ohmic contact layer 484;

[0252] quantum well layer 485;

[0253] P-type InP layer 486;

[0254] P-InP ohmic contact layer 4862.

[0255] In some embodiments, the N-type InP layer 482 is an N-type doped semiconductor, such as doped with a pentavalent element.

[0256] The P-type InP layer 486 is a P-type doped semiconductor, such as doped with a trivalent element.

[0257] The N-type InP layer 482 and the P-type InP layer 486 are doped with different impurity elements to form a PN junction.

[0258] In some embodiments, when a PN junction is formed, the concentration difference of carriers causes diffusion movement, and the result of the carrier diffusion movement is that the P-type InP layer 486 includes holes and negative ions, and the N-type InP layer 482 includes electrons and positive ions. Based on the charge principle, the holes are driven downward into the quantum well layer 485, and the electrons are driven upward into the quantum well layer 485.

[0259] In the quantum well layer 485, stimulated radiation causes discrete electron-hole pairs to recombine to generate photons, thereby effectively converting electrically injected carriers into photons and generating gain light. The photons generated by recombination in the quantum well layer 485 are reflected by the resonant cavity or distributed feedback grating to form positive feedback, thereby generating lasing light.

[0260] 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.

[0261] 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.

[0262] In some embodiments, an undoped i-InP intrinsic layer 4861 is formed below the P-type InP layer 486 .

[0263] There is a depletion region at the junction of the P region and the N region in the PN junction. The depletion region of the PN junction is narrow, and the carriers contain diffusion components, which seriously affects the modulation rate. By setting the i-InP intrinsic layer 4861 in the middle of the PN junction, the width of the depletion region is increased, so that the carriers drift to the PN junction under the action of a strong electric field, avoiding the influence of the carrier diffusion component on the laser 480, thereby improving the modulation rate.

[0264] In some embodiments, the growth material of the silicon waveguide layer 481 is silicon, and the InP light emitting region is an InP region. The lattice constants of the silicon material and the InP semiconductor material are quite different, and there is a large lattice mismatch between the two, which results in stress when the InP material is epitaxially grown on silicon. The stress limiting layer 483 can limit the stress between the silicon material and the InP semiconductor material within the layer, preventing the stress from being transmitted upward to the quantum well layer 485, so as to protect the quantum well layer 485.

[0265] In some embodiments, the quantum well layer 485 is an active region, and the quantum well layer 485 is a carrier reaching the target layer to recombine and generate photons in the quantum well layer 485. The refractive index of the quantum well material is relatively large, and the optical signal can be well confined in the quantum well layer 485 in the longitudinal direction.

[0266] In some embodiments, a P-type electrode 487 a is disposed on the surface of the P-InP ohmic contact layer 4862 .

[0267] The width of the N-InP ohmic contact layer 484 is greater than the width of the quantum well layer 485 , so that gaps are left at both ends of the N-InP ohmic contact layer 484 relative to the ends of the quantum well layer 485 , and N-type electrodes 487b can be formed at both ends of the N-InP ohmic contact layer 484 .

[0268] 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.

[0269] The growth material of the silicon waveguide layer 481 is silicon, and the InP modulation area is an InP area. The lattice constants of the silicon material and the InP semiconductor material are quite different, and there is a large lattice mismatch between the two, which leads to stress when the InP material is epitaxially grown on silicon, and thus the quality of hybrid integration is poor. For this reason, an intermediate bonding layer 489 is provided between the silicon waveguide layer 481 and the InP light-emitting area.

[0270] 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 forces 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.

[0271] Exemplarily, 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.

[0272] In some embodiments, the optical confinement factor of the silicon waveguide layer 481 is greater than the optical confinement factor 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 .

[0273] In some embodiments, the light field generated by the quantum well layer 485 is large and can be coupled downward into the silicon waveguide layer 481. Exemplarily, 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 high.

[0274] 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 layers are respectively gradiented to be the same, that is, when the transmission constants of the two layers are the same, the coupling efficiency between the two layers is the highest.

[0275] In some embodiments, laser 480 emits light downward from quantum well layer 485 and then outputs horizontally through silicon waveguide layer 481 .

[0276] In some embodiments, the laser output by the silicon waveguide layer 481 is a laser that does not carry a signal, and the silicon waveguide layer 481 is coupled to the splitter 710, so that the laser output by the laser 480 is transmitted to the splitter 710. The splitter 710 splits the laser into two paths of light, which are respectively transmitted to the optical modulator 460 for signal modulation.

[0277] In some embodiments, based on the above laser, the above 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 .

[0278] In some embodiments, the splitter 710 is disposed on the output optical path of the laser 480 to receive the light outputted by the waveguide layer of the laser 480 and split the light into two paths of light to be modulated. The 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. The combiner 720 is disposed on one side of the optical modulator 460 to combine the two paths of optical modulation signals modulated by the optical modulator 460.

[0279] In some embodiments, the optical modulator 460 is an optical modulator 460 whose two ends may be respectively formed with: the first tapered coupling region 460 a and the second tapered coupling region 460 c , and its structure will not be further described.

[0280] Fig. 22 FIG. 1 is a schematic diagram of a structure of an integrated heater inside an optical modulator according to some embodiments of the present disclosure. Fig. 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 gradient coupling region 460a and the second gradient coupling region 460c are respectively formed on both ends of the light modulator 460.

[0281] 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 .

[0282] 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 .

[0283] In some embodiments, the temperature of the hybrid integrated optical chip is adjusted by TEC so that the operating temperature of the hybrid integrated optical chip is maintained within a certain range. However, the power consumption is relatively large when the temperature is controlled by TEC. In the present disclosure, based on the fact that the sensitivity of InP semiconductor materials to temperature is stronger than that of Si-based materials to temperature, the temperature of a part of the optical chip, i.e., the first P-type InP region 466a and the second P-type InP region 466b, is adjusted instead of the temperature of the entire optical chip, so that the optical chip can work within a certain temperature range while reducing power consumption.

[0284] In the present disclosure, based on the fact that the sensitivity of InP semiconductor materials to temperature is stronger than that of Si materials to temperature, the temperature of a local area of ​​the optical chip is adjusted instead of the temperature of the entire optical chip, so that the optical chip can work within a certain temperature range, thereby achieving the purpose of temperature adjustment of the entire area of ​​the optical chip, thereby reducing power consumption.

[0285] 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 adjusting the temperature of the InP modulation region, the temperature of the entire optical chip is adjusted.

[0286] The temperature of the local area of ​​the optical chip, namely the InP modulation area, is adjusted by the first heating unit 491 and the second heating unit 492, so that the optical chip can work within a certain temperature range in a low-power manner. At the same time, by adjusting the temperature of the InP modulation area, the thermal stress when the InP modulation area is bonded to the Si-based substrate can be reduced, thereby improving the reliability and modulation rate of the optical modulator 460.

[0287] The first heating unit 491 is disposed adjacent to the first P-type InP region 466a to adjust the temperature of the first P-type InP region 466a and further adjust the temperature of a local area of ​​the optical chip to maintain the entire area of ​​the optical chip within a certain temperature range.

[0288] The second heating unit 492 is disposed adjacent to the first P-type InP region 466a to adjust the temperature of the first P-type InP region 466a through the second heating unit 492, and then adjust the temperature of a local area of ​​the optical chip to maintain the entire area of ​​the optical chip within a certain temperature range.

[0289] In some embodiments, in order to monitor the temperature of the InP modulation area in real time, a temperature sensor is embedded in the Si-based platform. The temperature of the InP modulation area is collected in real time by the temperature sensor, so that the temperature of the InP modulation area is adjusted in real time to achieve closed-loop control of temperature regulation.

[0290] In some embodiments, the first heating unit 491 and the second heating unit 492 may be in the form of heating resistors, and the first P-type InP region 466a and the second P-type InP region 466b are heated respectively by the heating resistors.

[0291] In some embodiments, in order to realize the power supply connection of the first heating part 491 and the second heating part 492, metal vias are opened in the layer where the first heating part 491 and the second heating part 492 are located. The metal vias are connected to the power supply metal area of ​​the optical chip, so as to heat the first heating part 491 and the second heating part 492.

[0292] In some embodiments, the area where the first heating part 491 and the second heating part 492 are located is formed by epitaxial growth of SiO2 material, and the bottom silicon 4611 is formed by epitaxial growth of Si material. The thermal conductivity of Si material is greater than that of SiO2 material, that is, the thermal conductivity of the bottom silicon 4611 is greater than that of the area where the heating part is located. Then, the heat generated by the first heating part 491 and the second heating part 492 will be conducted downward to the bottom silicon 4611, thereby reducing the temperature regulation efficiency.

[0293] 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 bottom silicon 4611 to reduce the heat conducted downward from the first heating portion 491 to the bottom silicon 4611.

[0294] A second heat isolating portion 494 is formed at one side of the second heating portion 492. The second heat isolating portion 494 penetrates downward from the cladding layer 414 to the bottom silicon 4611 to reduce the amount of heat conducted downward from the second heating portion 492 to the bottom silicon 4611.

[0295] In some embodiments, the first thermal isolation portion 493 and the second thermal isolation portion 494 may be in the form of a groove-type 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 bottom silicon 4611. The lower area corresponding to the first heating portion 491 is not hollowed out to ensure the support force of the first heating portion 491. The lower area corresponding to the second heating portion 492 is not hollowed out to ensure the support force of the second heating portion 4311.

[0296] The medium in the first heat isolation part 493 and the second heat isolation part 494 is air, and the thermal conductivity of air is extremely small, which is less than the thermal conductivity of SiO2 material, and the thermal conductivity of air is less than the thermal conductivity of InP material. The amount of heat generated by the first heating part 491 and the second heating part 492 that is conducted downward is very small, and the first heat isolation part 493 and the second heat isolation part 494 can block the path for the heat to be conducted downward. Furthermore, the heat generated by the first heating part 491 and the second heating part 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.

[0297] In some embodiments, the first thermal isolation portion 493 includes a first connection groove 4931 and a second connection groove 4932. The first connection groove 4931 extends downward to extend to the bottom silicon 4611 and partially hollows out the bottom silicon 4611. The second connection groove 4932 extends horizontally to increase the hollowing range, thereby increasing the thermal isolation area.

[0298] The second thermal isolation portion 494 includes a third connection groove 4941 and a fourth connection groove 4942. The third connection groove 4941 extends downward to extend to the bottom silicon 4611 and partially hollows out the bottom silicon 4611. The fourth connection groove 4942 extends horizontally to increase the hollowing range, thereby increasing the thermal isolation area.

[0299] Exemplarily, the first connection groove 4931 is formed by etching downward, and then the etching is continued and the etching range is increased to form the second connection groove 4932. Exemplarily, the shapes finally formed by the first heat isolation part 493 and the second heat isolation part 494 can be irregular shapes or regular shapes.

[0300] 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.

[0301] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A laser, characterized in that: The laser comprises from top to bottom: P-InP ohmic contact layer; P-type InP layer, used for outputting P-type carriers; A quantum well layer, used for receiving the P-type carriers; N-InP ohmic contact layer; An N-type InP layer is used to output N-type carriers to the quantum well layer, so that the N-type carriers and the P-type carriers are recombined in the quantum well layer to generate light; A waveguide layer, wherein the optical confinement factor of the waveguide layer is greater than the optical confinement factor of the quantum well layer, so that the light field in the quantum well layer is coupled downwardly into the waveguide layer, and the light generated in the quantum well layer is output.

2. The laser according to claim 1, characterized in that The waveguide layer is a silicon waveguide layer; The P-InP ohmic contact layer, the P-type InP layer, the quantum well layer, the N-InP ohmic contact layer, and the N-type InP layer constitute an InP light-emitting region, and the InP light-emitting region is located above the silicon waveguide layer; An intermediate bonding layer is formed between the silicon waveguide layer and the InP light emitting region.

3. The laser according to claim 1, characterized in that The waveguide layer is a silicon waveguide layer; The waveguide layer comprises, from bottom to top, respectively: underlying silicon; buried oxide layer; Silicon ridge waveguide.

4. The laser according to claim 1, characterized in that The propagation constant of the waveguide layer is the same as the propagation constant of the quantum well layer.

5. A hybrid integrated optical chip, characterized in that: include: A laser, wherein the laser is the laser according to any one of claims 1 to 4; A wave splitter is arranged on the output optical path of the laser to receive the light output by the waveguide layer of the laser and split the light into two paths of light to be modulated; An optical modulator is arranged on the output optical path of the splitter to receive two paths of light to be modulated and modulate the two paths of light to be modulated; The combiner is arranged at one side of the optical modulator and is used for combining two optical modulation signals generated by the optical modulator.

6. The hybrid integrated optical chip according to claim 5, characterized in that: The optical modulator comprises, from bottom to top, respectively: The silicon waveguide layer has a silicon contraction region corresponding to receiving two paths of light to be modulated formed at one end facing the splitter, and a silicon expansion region corresponding to coupling two paths of light modulation signals formed at 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 at one end facing the splitter, and a first InP contraction region corresponding to coupling two paths of light modulation signals formed at one end facing the combiner; The quantum well layer has a second InP expansion region corresponding to coupling two paths of light to be modulated formed at one end facing the splitter, and a second InP contraction region corresponding to coupling two paths of light modulation signals formed at one end facing the combiner; The P-type InP layer has a third InP expansion region corresponding to coupling two paths of light to be modulated formed at one end facing the splitter, and a third InP contraction region corresponding to coupling two paths of light modulation signals formed at 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.

7. The hybrid integrated optical chip according to claim 6, characterized in that: 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; Among them, the silicon flat area, the first InP flat area, the second InP flat area, and the third InP flat area corresponding to one light are vertically stacked in sequence to perform signal modulation in the second InP flat area.

8. The hybrid integrated optical chip according to claim 6, characterized in that: 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, respectively, so that a path of light to be modulated is coupled to the corresponding silicon contraction region, and is sequentially 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 is laterally coupled to the second InP flat region along the second InP expansion 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 zone gradually widens, and the waveguide widths of the first InP contraction zone, the second InP contraction zone, and the third InP contraction zone gradually narrow, respectively, so that an optical modulated signal is sequentially coupled downward from the second InP contraction zone to the first InP contraction zone in the N-type InP layer and the silicon expansion zone of the silicon waveguide layer, and is output along the silicon expansion zone.

9. The hybrid integrated optical chip according to claim 6, characterized in that: 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 are 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 to receive a path of light to be modulated output by the splitter, and the output end is used to transmit a corresponding path of light modulation signal to the combiner; The input end of the second silicon ridge waveguide is used to receive another path of light to be modulated output by the splitter, and the output end is used to transmit the corresponding another path of light modulation signal to the combiner.

10. An optical module, characterized in that: include: Circuit boards; A hybrid integrated optical chip is electrically connected to the circuit board, and the hybrid integrated optical chip is the hybrid integrated optical chip according to any one of claims 6 to 9.

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