Optical chip and optical module

Abstract

The invention discloses an optical chip and an optical module. The optical chip comprises a substrate and a SiO2 layer located above the substrate. The Si waveguide layer is embedded in the SiO2 layer, and the SiO2 layer is the Si waveguide layer. And the modulator component is positioned above the Si waveguide layer. The inner barrier layer is embedded in the SiO2 layer, and a closed space is defined by the inner barrier layer and the Si waveguide layer. A modulator component is located within the closed space. The pinhole density of the inner barrier layer is smaller than the pinhole density of the SiO2 layer, so that external water vapor and harmful gas can be prevented from entering a modulator component from the outside of the optical chip. The outer barrier layer is embedded in the SiO2 layer and located on the side away from the substrate, the pinhole density of the outer barrier layer is smaller than that of the SiO2 layer, external water vapor and harmful gas can be prevented from entering the optical chip from the outside of the optical chip, and the stability of the optical chip is improved.

Description

Technical Field

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

[0002] Optical communication technology is used in new services and application models such as cloud computing, mobile Internet, and video. In optical communication, optical modules are tools for converting optical and electrical signals into each other and are one of the key components in optical communication equipment. With the rapid development of 5G networks, optical modules, which are at the core of optical communication, have made great progress.

[0003] Traditional optical communication systems primarily utilize intensity modulation / direct demodulation (IMDD), directly modulating the intensity of the optical carrier at the transmitter and performing envelope detection on the receiver. This approach, with its simple structure and low cost, is widely used in modern communication systems. However, its drawbacks include a single modulation format and limited bandwidth per channel, which cannot meet the growing bandwidth demand. Coherent optical communication, with its advantages of high receiver sensitivity, high spectral efficiency, and compatibility with a variety of modulation formats, effectively offsets the shortcomings of direct demodulation of intensity modulation. Coherent demodulation can modulate information such as the amplitude, frequency, and phase of the optical carrier, promoting the development of optical digital transmission systems. Summary of the Invention

[0004] The present application provides an optical chip and an optical module, which can improve the reliability of the optical chip.

[0005] In one aspect, an optical chip provided in an embodiment of the present application includes:

[0006] substrate;

[0007] A SiO2 layer located above the substrate;

[0008] A Si waveguide layer is embedded in the SiO2 layer, and the SiO2 layer wraps the Si waveguide layer;

[0009] a modulator component located above the Si waveguide layer;

[0010] An inner barrier layer is embedded in the SiO2 layer, and the inner barrier layer and the Si waveguide layer are enclosed to form a closed space;

[0011] The modulator component is located within the closed space;

[0012] The pinhole density of the inner barrier layer is less than the pinhole density of the SiO2 layer;

[0013] an outer barrier layer, embedded in the SiO2 layer, the outer barrier layer being located on a side away from the substrate;

[0014] The pinhole density of the outer barrier layer is less than the pinhole density of the SiO2 layer.

[0015] On the other hand, the optical module provided in the embodiment of the present application includes:

[0016] A light source, which emits light that does not carry data;

[0017] an optical chip, connected to the light source, and modulating the light emitted by the light source;

[0018] The optical chip includes: a substrate;

[0019] A SiO2 layer located above the substrate;

[0020] A Si waveguide layer is embedded in the SiO2 layer, and the SiO2 layer wraps the Si waveguide layer;

[0021] a modulator component located above the Si waveguide layer;

[0022] An inner barrier layer is embedded in the SiO2 layer, and the inner barrier layer and the Si waveguide layer are enclosed to form a closed space;

[0023] The modulator component is located within the closed space;

[0024] The pinhole density of the inner barrier layer is less than the pinhole density of the SiO2 layer;

[0025] an outer barrier layer, embedded in the SiO2 layer, the outer barrier layer being located on a side away from the substrate;

[0026] The pinhole density of the outer barrier layer is less than the pinhole density of the SiO2 layer.

[0027] Beneficial effects of this application:

[0028] The present application discloses an optical chip and an optical module. The optical chip includes: a substrate and a SiO2 layer located above the substrate. The Si waveguide layer is embedded in the SiO2 layer, and the SiO2 layer is the Si waveguide layer. The modulator component is located above the Si waveguide layer. The inner barrier layer is embedded in the SiO2 layer, and the inner barrier layer and the Si waveguide layer are enclosed to form a closed space. The modulator component is located in the closed space. The pinhole density of the inner barrier layer is lower than that of the SiO2 layer, which is beneficial for blocking external water vapor and harmful gases from entering the modulator component through the outside of the optical chip. The outer barrier layer is embedded in the SiO2 layer, and the outer barrier layer is located on the side away from the substrate. The pinhole density of the outer barrier layer is lower than that of the SiO2 layer, which is beneficial for blocking external water vapor and harmful gases from entering the optical chip through the outside of the optical chip, thereby improving the stability of the optical chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below are schematic diagrams and are not intended to limit the actual dimensions of the products, actual processes of the methods, actual timing of signals, and the like involved in the embodiments of the present disclosure.

[0030] Figure 1 A connection diagram of an optical communication system;

[0031] Figure 2 This is a structural diagram of an optical network terminal;

[0032] Figure 3 is a structural diagram of an optical module according to some embodiments;

[0033] Figure 4 is an exploded structural diagram of an optical module according to some embodiments;

[0034] Figure 5 is a structural diagram of a fiber optic adapter, a light source, a coherent component, and a circuit board according to some embodiments;

[0035] Figure 6 is a partial cross-sectional schematic diagram of an optical module according to some embodiments;

[0036] Figure 7 A schematic diagram of the optical signal modulation principle of an optical chip provided according to some embodiments of the present disclosure;

[0037] Figure 8 A schematic cross-sectional view of an optical chip according to some embodiments of the present disclosure Figure 1 ;

[0038] Figure 9 A schematic cross-sectional view of an optical chip according to some embodiments of the present disclosure Figure 2 ;

[0039] Figure 10 A schematic diagram of the optical path within the cross section of an optical chip provided according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0040] In optical communication systems, light signals are used to carry the information to be transmitted. These signals are then transmitted via information transmission equipment such as optical fibers or optical waveguides to information processing equipment such as computers to complete the information transmission. Because light is passive when transmitted through optical fibers or optical waveguides, low-cost, low-loss information transmission is possible. Furthermore, the signals transmitted by information transmission equipment such as optical fibers or optical waveguides are optical signals, while the signals that information processing equipment such as computers can recognize and process are electrical signals. Therefore, in order to establish an information connection between information transmission equipment such as optical fibers or optical waveguides and information processing equipment such as computers, conversion between electrical and optical signals is necessary.

[0041] In the field of optical communications, optical modules implement the aforementioned conversion between optical and electrical signals. They include both an optical port and an electrical port. The optical port enables optical communication with information transmission equipment such as optical fibers or optical waveguides, while the electrical port enables electrical connection with an optical network terminal (e.g., an optical modem). The electrical connection is primarily used for power supply, I2C signal transmission, data transmission, and grounding. The optical network terminal transmits electrical signals to information processing equipment such as computers via network cables or wireless fidelity (Wi-Fi).

[0042] Figure 1 This is the connection diagram of the optical communication system. Figure 1 As shown, the optical communication system includes a remote server 1000 , a local information processing device 2000 , an optical network terminal 100 , an optical module 200 , an optical fiber 101 and a network cable 103 .

[0043] One end of optical fiber 101 is connected to remote server 1000, and the other end is connected to optical network terminal 100 via optical module 200. Optical fiber itself can support long-distance signal transmission, for example, signal transmission over several kilometers (6 to 8 kilometers). Furthermore, if repeaters are used, theoretically, transmission over an unlimited distance is possible. Therefore, in typical optical communication systems, the distance between remote server 1000 and optical network terminal 100 can typically reach several thousand, tens of kilometers, or even hundreds of kilometers.

[0044] One end of the network cable 103 is connected to the local information processing device 2000, and the other end is connected to the optical network terminal 100. The local information processing device 2000 can be any one or more of the following devices: a router, a switch, a computer, a mobile phone, a tablet computer, a television, etc.

[0045] The physical distance between the remote server 1000 and the optical network terminal 100 is greater than the physical distance between the local information processing device 2000 and the optical network terminal 100. The connection between the local information processing device 2000 and the remote server 1000 is completed by the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is completed by the optical module 200 and the optical network terminal 100.

[0046] Optical module 200 includes an optical port and an electrical port. The optical port is configured to connect to optical fiber 101, thereby establishing a bidirectional optical signal connection between optical module 200 and optical fiber 101. The electrical port is configured to connect to optical network terminal 100, thereby establishing a bidirectional electrical signal connection between optical module 200 and optical network terminal 100. Optical module 200 performs conversion between optical and electrical signals, thereby establishing an information connection between optical fiber 101 and optical network terminal 100. For example, optical signals from optical fiber 101 are converted to electrical signals by optical module 200 and then input into optical network terminal 100. Similarly, electrical signals from optical network terminal 100 are converted to optical signals by optical module 200 and then input into optical fiber 101. Since optical module 200 is a tool for converting optical and electrical signals and does not process data, the information remains unchanged during the aforementioned optical-to-electrical conversion process.

[0047] The optical network terminal 100 includes a roughly rectangular housing, an optical module interface 102, and a network cable interface 104 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200, thereby establishing a bidirectional electrical signal connection between the optical network terminal 100 and the optical module 200. The network cable interface 104 is configured to connect to the network cable 103, thereby establishing a bidirectional electrical signal connection between the optical network terminal 100 and the network cable 103. The connection between the optical module 200 and the network cable 103 is established through the optical network terminal 100. For example, the optical network terminal 100 transmits electrical signals from the optical module 200 to the network cable 103, and transmits electrical signals from the network cable 103 to the optical module 200. Therefore, the optical network terminal 100 serves as the host computer of the optical module 200 and can monitor the operation of the optical module 200. In addition to the optical network terminal 100, the host computer of the optical module 200 may also include an optical line terminal (OLT), etc.

[0048] The remote server 1000 establishes a bidirectional signal transmission channel with the local information processing device 2000 through the optical fiber 101 , the optical module 200 , the optical network terminal 100 and the network cable 103 .

[0049] Figure 2 This is a structural diagram of an optical network terminal. In order to clearly show the connection relationship between the optical module 200 and the optical network terminal 100, Figure 2Only the structure of the optical network terminal 100 related to the optical module 200 is shown. Figure 2 As shown, the optical network terminal 100 further includes a circuit board 105 disposed within the housing, a cage 106 disposed on the surface of the circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed within the cage 106. The electrical connector is configured to connect to the electrical port of the optical module 200; the heat sink 107 has protrusions such as fins to increase the heat dissipation area.

[0050] Optical module 200 is inserted into cage 106 of optical network terminal 100. Cage 106 secures optical module 200, and heat generated by optical module 200 is transferred to cage 106 and then dissipated through heat sink 107. After optical module 200 is inserted into cage 106, its electrical port connects to an electrical connector inside cage 106, establishing a bidirectional electrical signal connection between optical module 200 and optical network terminal 100. Furthermore, its optical port connects to optical fiber 101, establishing a bidirectional optical signal connection between optical module 200 and optical fiber 101.

[0051] Figure 3 is a structural diagram of an optical module according to some embodiments. Figure 4 FIG. 4 is a diagram of an exploded structure of an optical module according to some embodiments. Figure 5 FIG is a structural diagram of a fiber optic adapter, a light source, coherent components, and a circuit board according to some embodiments. Figure 3 、 Figure 4 and Figure 5 As shown, the optical module 200 includes a shell, a circuit board 300 , a light source 500 , coherent components, a DSP chip 600 and an optical fiber winding rack 700 disposed in the shell.

[0052] The housing includes an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing with two openings. The outer contour of the housing may be a square.

[0053] In some embodiments of the present disclosure, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicular to the base plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0054] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicularly to the base plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and arranged perpendicularly to the cover plate 2011. The two upper side plates are combined with the two lower side plates 2022 to achieve the upper shell 201 covering the lower shell 202.

[0055] The direction of the line connecting the two openings 204 and 205 may be consistent with the length direction of the optical module 200, or may be inconsistent with the length direction of the optical module 200. For example, the opening 204 is located at the end of the optical module 200 ( Figure 3 The opening 205 is also located at the end of the optical module 200 ( Figure 3 Alternatively, opening 204 is located at the end of optical module 200, while opening 205 is located on the side of optical module 200. Opening 204 is an electrical port, through which the gold finger of circuit board 300 extends and is inserted into a host computer (e.g., optical network terminal 100); opening 205 is an optical port, configured to receive an external optical fiber 101, thereby connecting the external optical fiber 101 to the light source 500 inside optical module 200.

[0056] The combined assembly of the upper housing 201 and the lower housing 202 facilitates installation of components such as the circuit board 300 and the light source 500 into the housing, with the upper housing 201 and the lower housing 202 providing encapsulation and protection for these components. Furthermore, during assembly of components such as the circuit board 300 and the light source 500, the positioning, heat dissipation, and electromagnetic shielding components of these components are easily arranged, facilitating automated production.

[0057] In some embodiments, the upper housing 201 and the lower housing 202 are generally made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0058] In some embodiments, the optical module 200 further includes an unlocking component located outside its housing, and the unlocking component 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.

[0059] For example, the unlocking component is located on the outer walls of the two lower side panels 2022 of the lower housing 202 and has a snap-fitting component that mates with the host computer cage (e.g., the cage 106 of the optical network terminal 100). When the optical module 200 is inserted into the host computer cage, the snap-fitting component of the unlocking component secures the optical module 200 in the host computer cage. When the unlocking component is pulled, the snap-fitting component of the unlocking component moves accordingly, thereby changing the connection between the snap-fitting component and the host computer, thereby releasing the snap-fitting relationship between the optical module 200 and the host computer, thereby allowing the optical module 200 to be removed from the host computer cage.

[0060] The circuit board 300 includes circuit traces, electronic components, and chips. The circuit traces connect the electronic components and chips together according to the circuit design to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips include, for example, microcontroller units (MCUs), laser driver chips, limiting amplifiers, clock and data recovery (CDR) chips, power management chips, and digital signal processing (DSP) chips.

[0061] 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 support the above-mentioned electronic components and chips; when the light source is located on the circuit board, the rigid circuit board can also provide stable support; the rigid circuit board can also be inserted into the electrical connector in the upper computer cage.

[0062] The circuit board 300 also includes a gold finger formed on its end surface. The gold finger is composed of a plurality of independent pins. The circuit board 300 is inserted into the cage 106, and the gold finger is connected to the electrical connector in the cage 106. The gold finger can be provided on the surface of only one side of the circuit board 300 (for example, Figure 4 The gold fingers are configured to establish electrical connections with a host computer to provide power, grounding, I2C signal transmission, data signal transmission, etc.

[0063] Of course, some optical modules also use flexible printed circuits. These are typically used in conjunction with rigid printed circuits to complement them. For example, a flexible printed circuit can be used to connect a rigid printed circuit to a light source.

[0064] The circuit board 300 may include a first circuit board 301, a second circuit board 302 and a third circuit board 303. The first circuit board 301 and the second circuit board 302 are both rigid circuit boards, and the third circuit board 303 is a flexible circuit board. The second circuit board 302 is stacked and placed on one end of the first circuit board 301 close to the light source 500. The second circuit board 302 is located between the first circuit board 301 and the upper shell 201. The first circuit board 301 and the second circuit board 302 are connected through the third circuit board 303.

[0065] The optical module may include a light source 500. The light source 500 may be connected to the second circuit board 302 and may be configured to emit a light beam having a preset specific wavelength.

[0066] The optical module may include a transmitting optical fiber adapter 800 and a receiving optical fiber adapter 801. The transmitting optical fiber adapter 800 is used to transmit high-speed optical signals, and the receiving optical fiber adapter 801 is used to receive high-speed optical signals.

[0067] The coherent component, placed on the circuit board, is used to achieve high-speed optical-to-electrical signal conversion. Specifically, the coherent component includes an optical transmission interface, an optical reception interface, and a local oscillator optical interface. The optical transmission interface extends a first optical fiber, the optical reception interface extends a second optical fiber, and the local oscillator optical interface extends a third optical fiber. The optical transmission interface is connected to the transmission fiber adapter 800, the optical reception interface is connected to the reception fiber adapter 801, and the local oscillator optical interface is connected to the light source 500. The coherent component is connected to the transmission fiber adapter, the reception fiber adapter, and the light source 500 via the optical transmission interface, the optical reception interface, and the local oscillator optical interface, respectively. The coherent component is also connected to the DSP chip 600.

[0068] The narrow-linewidth, high-power laser light emitted by light source 500 is input into the coherent component through the local oscillator optical interface. The laser light is then split into two beams within the coherent component. One beam, acting as the transmit beam, enters the coherent modulator within the coherent component. Driven by the high-speed electrical signal from the DSP chip 600, the electrical-to-optical signal is converted. The converted high-speed optical signal is then output from the module's optical transmit interface. The other beam, acting as the local oscillator beam, undergoes coherent demodulation with the high-speed optical signal input into the coherent component from the module's optical receive port. The demodulated electrical signal enters the DSP chip 600 for signal processing, completing the optical-to-electrical signal conversion. The narrow-linewidth, high-power laser light is a beam of a specific wavelength.

[0069] Light source 500 may include an internal fiber optic adapter, a first optical fiber extending from the internal fiber optic adapter, a local oscillator optical fiber extending from the local oscillator optical interface, and the first optical fiber and the local oscillator optical fiber being fusion-connected to connect the internal fiber optic adapter to the local oscillator optical interface. A second optical fiber extending from a transmitting fiber optic adapter 800, a transmitting optical fiber extending from the transmitting optical interface, and the second optical fiber and the transmitting optical fiber being fusion-connected to connect the transmitting fiber optic adapter 800 to the transmitting optical interface. A third optical fiber extending from a receiving fiber optic adapter 801, a receiving optical fiber extending from the receiving optical interface, and the third optical fiber and the receiving optical fiber being fusion-connected to connect the receiving fiber optic adapter 801 to the receiving optical interface.

[0070] Because there is a certain failure rate when fusion splicing two optical fibers, a certain amount of fiber length must be reserved to ensure successful splicing of the two fibers. This allows for continued splicing after a splice failure. Furthermore, because the connection point between the first optical fiber and the local oscillator fiber is located near the internal fiber adapter, the connection point between the second optical fiber and the transmitting optical fiber is located near transmitting optical fiber adapter 800, and the connection point between the third optical fiber and the receiving optical fiber is located near receiving optical fiber adapter 801, the lengths of the first optical fiber, local oscillator fiber, transmitting optical fiber, and receiving optical fiber are relatively long.

[0071] The fiber winding rack 700 is used to secure the optical fibers. Specifically, because the circuit board 300 is equipped with high-frequency signal lines and numerous components, the optical fibers cannot be laid directly on the surface of the circuit board 300. Furthermore, because the first optical fiber, local oscillator optical fiber, transmitting optical fiber, and receiving optical fiber are relatively long, to prevent damage to the first optical fiber, local oscillator optical fiber, transmitting optical fiber, and receiving optical fiber caused by the upper housing, a fiber winding rack 700 is provided between the coherent assembly and the upper housing 201 to secure the optical fibers.

[0072] The first optical fiber, local oscillator optical fiber, transmitting optical fiber and receiving optical fiber can be neatly fixed on the optical fiber winding frame 700, which not only avoids the upper shell from damaging the first optical fiber, local oscillator optical fiber, transmitting optical fiber and receiving optical fiber, but also avoids the signal crosstalk problem caused by directly laying the optical fiber on the surface of the circuit board 300.

[0073] Figure 6 FIG. 1 is a schematic partial cross-sectional view of an optical module according to some embodiments. Figure 6 As shown, in some embodiments, a coherent optical component may include an optical chip 400. The light emitted by the light source 500 is light that does not carry data. This light that does not carry data is the light to be modulated. The light to be modulated enters the optical chip 400, which modulates it and adds an electrical signal to the light to be modulated to obtain light that carries data, i.e., generates an optical transmission signal, thereby transmitting the optical signal. External light enters the optical chip 400, which demodulates it, thereby receiving the optical signal.

[0074] The coherent optical component may include a transimpedance amplifier. The optical chip 400 demodulates the received signal light and converts it into an electrical signal. The transimpedance amplifier amplifies the electrical signal.

[0075] A metal connection portion is provided on the lower surface of the optical chip 400 , and the metal connection portion is bonded to the circuit board through metal.

[0076] In some embodiments, optical chip 400 may be a silicon photonic chip. A silicon photonic chip includes a Mach-Zehnder modulator (MZM) with an integrated silicon photonic phase modulator for optical signal modulation and demodulation. Because silicon photonic chips are easily etched, other functional components such as optical splitters, combiners, mixers, and photodetectors can be integrated within them, thereby achieving more functionality. Figure 9 FIG. 1 is a schematic diagram of a layout of a coherent optical chip according to some embodiments. Figure 9 As shown, multiple channels are integrated inside the silicon photonic chip. Each channel includes a silicon photonic phase modulator, a thermal phase regulator, etc. The silicon photonic phase modulator, the thermal phase regulator, etc. are made of silicon materials respectively. The silicon photonic phase modulator, the thermal phase regulator, etc. are connected to each other through silicon waveguides.

[0077] However, the fundamental properties of silicon materials lead to drawbacks in optical modulator implementation, such as relatively low modulation efficiency, high capacitance, limited bandwidth, and high optical loss. Consequently, because silicon photonic phase modulators operate based on carriers, current long-haul 400G optical modules can only achieve transmission rates of 50-60Gbaud per channel. However, in next-generation optical modules for 1.6-3.2T PAM short-haul transmission and 800G-3.2T coherent long-haul transmission, transmission rates per channel must exceed 100Gbaud, necessitating a silicon photonic phase modulator with a modulation rate exceeding 100Gbaud. However, when the modulation rate of a silicon photonic phase modulator approaches 100Gbaud, the driver's output voltage swing is high, resulting in high power consumption and making it unsuitable for optical modules.

[0078] In some embodiments, optical chip 400 may be a thin-film lithium niobate chip. Thin-film lithium niobate exhibits properties such as the linear electro-optic effect. An applied electric field causes a linear change in its refractive index in the corresponding direction, allowing light waves transmitted through the medium to have controllable intensity, phase, and other information. Therefore, thin-film lithium niobate can be used as the material for optical modulators, achieving high modulation efficiency. However, thin-film lithium niobate is relatively hard and difficult to etch, making it difficult to integrate multiple functional devices on its surface. Furthermore, thin-film lithium niobate chips exhibit low optical loss.

[0079] In some embodiments, the optical chip 400 can be a hybrid InP / Si optical chip. The hybrid InP / Si optical chip includes multiple channels, each channel includes an InP modulator, a thermal phase regulator, etc. The InP modulator is made of InP material, and the thermal phase regulator is made of silicon material. The InP modulator, thermal phase regulator, etc. are connected to each other through silicon waveguides to form a high-traveling-wave MZM. The hybrid InP / Si optical chip provided by the present disclosure realizes the hybrid integration of Si-based chips and InP materials. The InP material provides high-speed modulation, and the Si base provides highly integrated silicon optical circuits, so that the optical chip 400 can have the high-speed modulation characteristics of the InP material, so that the optical chip 400 can meet the needs of high baud rate modulation.

[0080] In some embodiments, an InP-based material is bonded to a Si-based material, and then an InP phase modulator, a silicon photonic circuit, etc. are fabricated on the bonded materials.

[0081] Figure 7 FIG. 1 is a schematic diagram of an optical signal modulation principle of an optical chip provided according to some embodiments of the present disclosure, such as Figure 7 As shown, the optical chip 400 is optically connected to the light source 500 .

[0082] The optical chip 400 can be a monolithic integrated optical chip, for example, a silicon photonic chip. Since the surface of the silicon photonic chip is easy to etch, other functional devices such as splitters, combiners, mixers, photodetectors, etc. can be integrated inside it to achieve more functions. A silicon-based optical modulator is integrated inside the silicon photonic chip. The silicon-based optical modulator uses the plasma dispersion effect of silicon material to achieve control of the light field, thereby achieving optical signal modulation. However, the basic characteristics of silicon material lead to defects in the implementation of optical modulators, such as low modulation efficiency, large capacitance, limited bandwidth, and large optical loss.

[0083] The optical chip 400 can be a hybrid integrated optical chip. A hybrid integrated optical chip refers to an optical chip in which the optical modulator growth platform is different from the growth platform of other functional devices, such as a splitter, a combiner, a mixer, a photodetector, etc. For example, since silicon-based platforms are easy to etch, the growth platforms of the splitter, the combiner, the mixer, the photodetector, etc. adopt a silicon-based platform. The optical modulator integrated inside the hybrid integrated optical chip is a non-silicon-based optical modulator. Non-silicon-based optical modulators, such as InP-based optical modulators. InP-based optical modulators perform optical signal modulation based on the quantum well-confined Stark effect. By controlling the change of the external electric field, the carriers are changed to achieve a change in the refractive index, thereby achieving optical signal modulation.

[0084] In the present disclosure, an example is given in which the optical chip 400 may be a hybrid integrated optical chip, and the non-silicon-based optical modulator integrated inside the optical chip 400 is an InP-based optical modulator.

[0085] The optical chip 400 may include a Si-based platform 410. A beam splitter, a beam combiner, a mixer, a photodetector, etc. are formed on the surface of the Si-based platform 410.

[0086] The optical chip 400 may include an InP modulation region 420. An InP modulator is disposed in the InP modulation region 420.

[0087] The InP modulation region 420 is located in the Si-based platform 410 , so that the Si-based platform 410 wraps the InP modulation region 420 in front, back, left, right, and bottom directions.

[0088] The laser light generated by the 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 an integrated optical splitter inside the optical chip 400. The first light beam, serving as the light source of the optical emission signal, is transmitted to the InP modulation area 420 for optical signal modulation. In some embodiments, the first light beam is split into two light beams of the same wavelength by a polarization beam splitter, such as a first sub-beam and a second sub-beam. The InP modulation area 420 performs signal modulation on the first sub-beam and the second sub-beam, respectively, to generate a first modulated optical signal and a second modulated optical signal, respectively. The first modulated optical signal and the second modulated optical signal are combined by the polarization combiner 460 to generate an optical emission signal. The polarization combiner 460 can adjust the polarization direction of the first sub-beam so that the polarization directions of the first sub-beam and the second sub-beam are different. The polarization combiner 460 can combine the first and second sub-beams after adjusting the polarization directions. The optical emission signal is coupled out of the optical chip 400 to the outside. The second light beam is coupled to the optical demodulation unit 470 as local oscillator light. The external optical signal is also coupled to the optical demodulation unit 470. The second light beam and the external light signal are coherently demodulated in the optical demodulation unit 470 to demodulate corresponding electrical signals.

[0089] In some embodiments, the InP modulators provided in the InP modulation region 420 include a first InP modulator 421 , a second InP modulator 422 , a third InP modulator 423 , and a fourth InP modulator 424 .

[0090] The first light beam is split by the polarization beam splitter into two beams of the same wavelength, such as the first sub-beam and the second sub-beam. The first InP modulator 421 and the second InP modulator 422 perform I modulation and Q modulation on the first sub-beam, respectively, thereby generating a first modulated optical signal by performing IQ high-order modulation on the first sub-beam. The third InP modulator 423 and the fourth InP modulator 424 perform I modulation and Q modulation on the second sub-beam, respectively, thereby generating a second modulated optical signal by performing IQ high-order modulation on the TE polarized light.

[0091] In the present disclosure, the optical chip 400 is a hybrid integrated optical chip, which realizes the hybrid integration of Si material and InP material, so as to utilize InP material to provide high-speed modulation and Si material to provide highly integrated silicon optical circuits, so that the optical chip 400 can have the high-speed modulation characteristics of InP material, so that the optical chip 400 can meet the requirements of high baud rate modulation.

[0092] Figure 8 A schematic cross-sectional view of an optical chip according to some embodiments of the present disclosure Figure 1 .like Figure 8 As shown, ( Figure 8 The up and down directions Figure 6 On the contrary, the Si-based platform 410 includes a substrate layer 411. A Si waveguide layer 413 and a SiO2 layer 414 may be disposed above the substrate layer 411. The SiO2 layer 4604 wraps the Si waveguide layer 413. The Si waveguide layer 413 includes a plurality of Si waveguides.

[0093] In some embodiments, a metal connection is provided on top of the SiO 2 layer 414 .

[0094] Modulator components may be disposed within the SiO 2 layer 414 .

[0095] like Figure 8 As shown, an InP waveguide 432 is provided above the Si waveguide layer 4603 , and the InP waveguide 432 is embedded in the SiO 2 layer 414 ; the Si waveguide layer 413 is used to couple light into the InP waveguide 431 .

[0096] The InP waveguide 432 includes an n-InP layer 4321, a first n-InP protrusion 4321a and a second n-InP protrusion 4321b are arranged on the top of the n-InP layer 4321, a gap is set between the first n-InP protrusion 4321a and the second n-InP protrusion 4321b, a quantum well layer (Quantum Well, QW) 4322 and a p-InP layer 4323 are set above the first n-InP protrusion 4321a and the second n-InP protrusion 4321b.

[0097] In some embodiments, light enters the InP waveguide through the Si waveguide layer 413 .

[0098] In some embodiments of the present application, when preparing a hybrid InP / Si optical chip, a Si platform is prepared and a groove is formed on the Si platform; an InP material including an n-InP layer 4321, a quantum hydrazine layer 4322, and a p-InP layer 4323 is set in the groove, and the InP material is processed to form an InP waveguide 432; SiO2 material is filled around the InP waveguide 432, so that a continuous SiO2 layer 4604 is wrapped around the InP waveguide 432.

[0099] For the sake of convenience, the first n-InP protrusion 4321 a and the quantum dot layer 4322 and the p-InP layer 4323 disposed above the first n-InP protrusion 4321 a are referred to as a modulator component 415 .

[0100] Figure 9 A schematic cross-sectional view of an optical chip according to some embodiments of the present disclosure Figure 2 . Figure 8 and Figure 9 is the cross section of the optical chip in different directions. Figure 9 As shown, the optical chip may include an outer barrier layer 450 . The outer barrier layer 450 is embedded in the SiO 2 layer 414 .

[0101] In some embodiments, outer barrier layer 450 may be a SiN layer. Compared to SiO2 layer 414, outer barrier layer 450 has a denser structure. The pinhole density of outer barrier layer 450 is lower than that of SiO2 layer 414, which helps prevent external moisture and harmful gases from entering the optical chip through the exterior of the optical chip.

[0102] The optical chip 400 may have an opening 417. The optical chip 400 may include a metal connection 416, which may be located below the outer barrier layer 450. The opening 417 may expose a portion of the metal connection 416 outside the SiO2 layer 414 for metal bonding.

[0103] In some embodiments, the area of ​​the opening 417 is smaller than the area of ​​the metal connection portion 416 , so that a portion of the metal connection portion 416 is embedded in the SiO 2 layer 414 , thereby improving the firmness of the metal connection portion 416 .

[0104] The opening is located on the surface of the SiO2 layer, and the opening is located on the side of the SiO2 layer facing away from the substrate.

[0105] The opening 417 may penetrate the outer barrier layer 450, and the metal connection portion 416 is located below the outer barrier layer 450. Part of the metal connection portion 416 is located within the downward projection of the outer barrier layer 450, thereby improving the stability of the metal connection portion 416.

[0106] The outer barrier layer is embedded in the SiO2 layer and is located on a side away from the substrate.

[0107] The optical chip may include an inner barrier layer 440. The inner barrier layer 440 may cover the modulator component 415. The inner barrier layer 440 may be a SiN layer. Compared to the SiO2 layer 414, the inner barrier layer 440 has a denser structure. The pinhole density in the inner barrier layer 440 is lower than that in the SiO2 layer 414, which helps prevent external moisture and harmful gases from entering the modulator component 415 through the exterior of the optical chip.

[0108] The inner barrier layer 440 may include a first inner barrier portion 441. The first inner barrier portion 441 is located above the modulator component 415 to prevent moisture and harmful gases from entering the modulator component 415 from above.

[0109] The inner barrier layer 440 may include a second inner barrier portion 442. The second inner barrier portion 442 is located on the left side of the modulator component 415 to prevent moisture and harmful gases from entering the modulator component 415 through the left side.

[0110] The second inner barrier 442 is embedded in the SiO2 layer 414. The pinhole density of the second inner barrier 442 is smaller than that of the SiO2 layer 414, which is beneficial for preventing external moisture and harmful gases from entering the modulator component 415 through the outside of the optical chip.

[0111] In some embodiments, the second inner barrier 442 is located above the Si waveguide layer 413 .

[0112] The inner barrier layer 440 may include a third inner barrier portion 443. The third inner barrier portion 443 is located on the right side of the modulator component 415 to prevent moisture and harmful gases from entering the modulator component 415 through the right side.

[0113] The third inner barrier 443 is embedded in the SiO2 layer 414. The pinhole density of the third inner barrier 443 is smaller than that of the SiO2 layer 414, which is beneficial for preventing external water vapor and harmful gases from entering the modulator component 415 through the outside of the optical chip.

[0114] In some embodiments, the third inner barrier 443 is located above the Si waveguide layer 413 .

[0115] The pinhole density of the Si waveguide layer 413 is smaller than that of the SiO 2 layer 414 , which helps to prevent external moisture and harmful gases from entering the modulator component 415 through the outside of the optical chip.

[0116] In some embodiments, the inner barrier layer 440 and the Si waveguide layer 413 form a closed space within which the modulator component 415 is located. The inner barrier layer 440 and the Si waveguide layer 413 help prevent external moisture and harmful gases from entering the modulator component 415 through the exterior of the optical chip.

[0117] In some embodiments, the inner barrier layer 440 may be fabricated using a silicon-on-insulator process in an integrated circuit, such as plasma-enhanced chemical vapor deposition (PECVD) or low-pressure chemical vapor deposition (LPCVD).

[0118] The outer barrier layer 450 may be fabricated using a silicon-on-insulator process in integrated circuits, such as plasma-enhanced chemical vapor deposition or low-pressure chemical vapor deposition.

[0119] In some embodiments, the optical chip may include a double-layer motion size converter 4142 . The double-layer motion size converter 4142 is coupled to the optical IO interface 490 of the optical fiber and can transmit light in the optical IO interface 490 to the Si waveguide layer 413 .

[0120] The optical IO interface 490 and the optical chip can be butt-coupled and sealed with epoxy resin.

[0121] Figure 10 Schematic diagram of the optical path in the cross section of an optical chip according to some embodiments of the present disclosure. Figure 10 As shown, the light of the optical IO interface 490 is transmitted through the upper layer of the double-layer motion size converter 4142 to the lower layer of the double-layer motion size converter 4142, and then transmitted to the Si waveguide layer 413. After lateral propagation through the Si waveguide layer 413, it is transmitted upward to the modulator component 415 and modulated in the modulator component 415.

[0122] In some embodiments, a heater and temperature sensor embedded in the PIC can be used to maintain a certain temperature, replacing the traditional TEC temperature control method.

[0123] It should be noted that, in this specification, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a circuit structure, article, or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such circuit structure, article, or device. In the absence of further limitations, the phrase "comprising a ..." to define an element does not exclude the presence of other identical elements in the circuit structure, article, or device comprising the element.

[0124] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the disclosure of the invention herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the claims.

[0125] The above-described embodiments of the present application do not constitute a limitation on the scope of protection of the present application.

[0126] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. An optical chip, characterized in that: include: substrate; A SiO2 layer located above the substrate; A Si waveguide layer is embedded in the SiO2 layer, and the SiO2 layer wraps the Si waveguide layer; a modulator component located above the Si waveguide layer; An inner barrier layer is embedded in the SiO2 layer, and the inner barrier layer and the Si waveguide layer are enclosed to form a closed space; The modulator component is located within the closed space; The pinhole density of the inner barrier layer is less than the pinhole density of the SiO2 layer; an outer barrier layer, embedded in the SiO2 layer, the outer barrier layer being located on a side away from the substrate; The pinhole density of the outer barrier layer is less than the pinhole density of the SiO2 layer.

2. The optical chip according to claim 1, wherein: The modulator component includes: an n-InP layer, an n-InP protrusion, a quantum hydrazine layer and a p-InP layer; The n-InP protrusion is located above the n-InP layer; The quantum hydrazine layer is located above the n-InP protrusion; The p-InP layer is located above the quantum hydrazine layer.

3. The optical chip according to claim 1, wherein: The optical chip includes: an opening, located on a surface of the SiO2 layer, the opening penetrating the outer barrier layer; a metal connection portion, embedded in the SiO2 layer, the metal connection portion being located between the outer barrier layer and the modulator component; The opening allows the metal connection portion to be exposed on the surface of the SiO2 layer.

4. The optical chip according to claim 3, wherein: An area of ​​the opening is smaller than an area of ​​the metal connecting portion.

5. The optical chip according to claim 1, wherein: The inner barrier layer is a SiN layer; the outer barrier layer is a SiN layer.

6. The optical chip according to claim 1, wherein: include: A double-layer motion size converter coupled to an optical IO interface; The dual-layer motion dimension converter transfers light within the optical IO interface to the Si waveguide layer.

7. The optical chip according to claim 1, wherein: The modulator component is a thin film lithium niobate component.

8. An optical module, characterized in that: include: A light source, which emits light that does not carry data; an optical chip, connected to the light source, and modulating the light emitted by the light source; The optical chip includes: a substrate; A SiO2 layer located above the substrate; A Si waveguide layer is embedded in the SiO2 layer, and the SiO2 layer wraps the Si waveguide layer; a modulator component located above the Si waveguide layer; An inner barrier layer is embedded in the SiO2 layer, and the inner barrier layer and the Si waveguide layer are enclosed to form a closed space; The modulator component is located within the closed space; The pinhole density of the inner barrier layer is less than the pinhole density of the SiO2 layer; an outer barrier layer, embedded in the SiO2 layer, the outer barrier layer being located on a side away from the substrate; The pinhole density of the outer barrier layer is less than the pinhole density of the SiO2 layer.

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