An optical module

Abstract

An optical module (200) comprises a fiber array (1300), an optical modulation chip (1100) and a hybrid integrated optical amplifier chip (1200), the fiber array (1300) transmits the light to be modulated into the optical modulation chip (1100), the optical modulator (1130) modulates the light to be modulated and outputs the first modulated light and the second modulated light respectively, the hybrid integrated optical amplifier chip (1200) is integrated with the first optical amplifier (1210), the second optical amplifier (1220), the first optical waveguide (1230) and the second optical waveguide (1250) respectively, the first modulated light and the second modulated light are output and transmitted into the hybrid integrated optical amplifier chip (1200), the first optical amplifier (1210) and the second optical amplifier (1220) amplify the first modulated light and the second modulated light respectively, the amplified first modulated light and the second modulated light return to the optical modulation chip (1100) along the first optical waveguide (1230) and the second optical waveguide (1250) respectively for wave combining, the hybrid integrated optical amplifier chip (1200) can simultaneously exert the gain characteristics of the optical amplifier and the low transmission loss characteristics of the silicon-based waveguide and increase the stability of the optical path.

Description

An optical module

[0001] This disclosure claims priority to patent application number 202410127654.4 filed on January 30, 2024 with the China Patent Office and priority to patent application number 202410128186.2 filed on January 30, 2024 with the China Patent Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of optical communication technology, and in particular to an optical module. Background Art

[0003] With the development of new services and applications such as cloud computing, mobile internet, and video, advances in optical communication technology are becoming increasingly important. As a key component in optical communication equipment, optical modules enable photoelectric signal conversion. As optical communication technology evolves, the data transmission rate of these modules continues to increase.

[0004] Summary of the Invention

[0005] The optical module provided by the present disclosure includes: a circuit board having a notch on its surface; a substrate connected to the circuit board via the notch; an optical fiber array provided on the surface of the substrate for transmitting light to be modulated and modulated light after multiplexing; an optical modulation chip provided on the surface of the substrate and coupled to the optical fiber array for receiving the light to be modulated output by the optical fiber array, wherein the optical modulation chip has an optical modulator and an optical combiner integrated therein, and the optical modulator is used to modulate the light to be modulated and then output a first modulated light and a second modulated light, respectively, wherein the first modulated light and the second modulated light have different polarization states; a hybrid integrated optical amplifier chip provided on the surface of the substrate and coupled to the optical modulation chip, wherein the hybrid integrated optical amplifier chip has a first optical amplifier, a second optical amplifier, and a first optical combiner integrated therein. a first optical waveguide optically connected to the optical amplifier, and a second optical waveguide optically connected to the second optical amplifier; wherein the first optical amplifier and the second optical amplifier are both polarization state devices, the first optical amplifier has a first preset polarization state to optically amplify the first modulated light output by the optical modulation chip, and the second optical amplifier has a second preset polarization state to optically amplify the second modulated light output by the optical modulation chip; the first optical waveguide is used to return the amplified first modulated light to the optical modulation chip and connect it to the optical combiner, and the second optical waveguide is used to return the amplified first modulated light to the optical modulation chip and connect it to the optical combiner, and the amplified first modulated light and the amplified second modulated light are combined in the optical combiner. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] 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.

[0007] FIG1 is a partial architecture diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0008] FIG2 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0009] FIG3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0010] FIG4 is an exploded view of an optical module according to some embodiments of the present disclosure;

[0011] FIG5 is a diagram of an optical amplification structure of a coherent optical module according to some embodiments of the present disclosure;

[0012] FIG6 is a schematic structural diagram of an optical modulator provided according to some embodiments of the present disclosure;

[0013] FIG7 is a schematic diagram of a coupling structure of a hybrid integrated optical amplifier chip and an optical modulation chip according to some embodiments of the present disclosure;

[0014] FIG8 is a schematic diagram of another coupling structure of a hybrid integrated optical amplifier chip and an optical modulation chip according to some embodiments of the present disclosure;

[0015] FIG9 is a schematic structural diagram of a first optical amplification unit in a hybrid integrated optical amplification chip according to some embodiments of the present disclosure;

[0016] FIG10 is a schematic diagram of an assembly relationship between a circuit board and a substrate according to some embodiments of the present disclosure;

[0017] FIG11 is a first diagram of a packaging structure of an optical module according to some embodiments of the present disclosure;

[0018] FIG12 is a second diagram of a packaging structure of an optical module provided according to some embodiments of the present disclosure;

[0019] FIG13 is another packaging structure diagram of an optical module according to some embodiments of the present disclosure;

[0020] FIG14 is another packaging structure diagram of an optical module according to some embodiments of the present disclosure;

[0021] FIG15 is another packaging structure diagram of an optical module according to some embodiments of the present disclosure;

[0022] FIG16 is a structural diagram of an end-face coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0023] FIG17 is an exploded view of end-face coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0024] FIG18 is an exploded view of a lens coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0025] FIG19 is a structural diagram of a substrate, an optical modulation chip, and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0026] FIG20 is an exploded view of a substrate, an optical modulation chip, and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0027] FIG21 is a top view of end-face coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0028] FIG22 is a top view of a lens coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure;

[0029] FIG23 is a schematic diagram of an optical path corresponding to a coupling mode between an optical modulation chip and a hybrid integrated optical amplifier chip in an optical module according to some embodiments of the present disclosure;

[0030] FIG24 is a schematic diagram of an optical path corresponding to another coupling mode between an optical modulation chip and a hybrid integrated optical amplifier chip in an optical module according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0031] Some embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, the embodiments described are only some of the embodiments of the present disclosure, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments provided in the present disclosure are within the scope of protection of the present disclosure.

[0032] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as open and inclusive, that is, "including, but not limited to"; the terms "first" and "second" are not to be understood as indicating or implying relative importance or indicating an upper limit on quantity; the term "plurality" means two or more; the term "connected" is to be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, or an integral connection, and can be directly connected or indirectly connected through an intermediate medium; the use of the terms "suitable for" or "configured to" means open and inclusive language, which does not exclude equipment that is suitable for or configured to perform additional tasks or steps; terms such as "parallel", "perpendicular", "same", "consistent", "level" and so on are not limited to absolute mathematical theoretical relationships, but also include acceptable error ranges generated in practice, and also include differences based on the same design concept but due to manufacturing reasons.

[0033] In optical communication technology, to establish information transmission between information processing devices, it is necessary to load the information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When transmitting optical signals within information transmission equipment, they can reduce optical power loss, thereby enabling high-speed, long-distance, and low-cost information transmission. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment typically includes optical network units (ONUs), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment typically includes optical fibers and optical waveguides.

[0034] Optical modules can convert optical signals into electrical signals between information processing devices and information transmission devices. For example, at least one of the optical signal input or output ends of an optical module is connected to an optical fiber, and at least one of the electrical signal input or output ends of the optical module is connected to an optical network terminal. A first optical signal from the optical fiber is transmitted to the optical module, which converts the first optical signal into a first electrical signal and transmits the first electrical signal to the optical network terminal. A second electrical signal from the optical network terminal is transmitted to the optical module, which converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber. Because multiple information processing devices can transmit information via electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, rather than all of them. Here, the information processing device directly connected to the optical module is referred to as the optical module's host computer. Furthermore, the optical signal input or output end of the optical module can be referred to as an optical port, and the electrical signal input or output end of the optical module can be referred to as an electrical port.

[0035] FIG1 is a partial structural diagram of an optical communication system according to some embodiments. As shown in FIG1 , 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 .

[0036] One end of optical fiber 101 extends toward remote information processing device 1000, and the other end of optical fiber 101 is connected to optical module 200 through the optical port of optical module 200. Optical signals can be totally reflected in optical fiber 101, and the propagation of the optical signal in the direction of total reflection can almost maintain the original optical power. The optical signal undergoes multiple total reflections in optical fiber 101 to transmit the optical signal from remote information processing device 1000 to optical module 200, and vice versa, thereby achieving long-distance, low-power information transmission.

[0037] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 may be detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide data signals to the optical module 200, receive data signals from the optical module 200, or monitor or control the operating status of the optical module 200.

[0038] The host computer 100 includes a substantially rectangular housing and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and the optical module 200.

[0039] The host computer 100 also includes an external electrical interface that can access an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104. The network cable interface 104 is configured to access a network cable 103 so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100, so that an electrical signal connection is established between the local information processing device 2000 and the host computer 100 via the network cable 103. For example, a third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 via the network cable 103. The host computer 100 generates a second electrical signal based on the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200. The optical module 200 converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber 101. The second optical signal is then transmitted to the remote information processing device 1000 via the optical fiber 101. For example, a first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101. The first optical signal from the optical fiber 101 is transmitted to the optical module 200. The optical module 200 converts the first optical signal into a first electrical signal. The optical module 200 transmits the first electrical signal to the host computer 100. The host computer 100 generates a fourth electrical signal based on the first electrical signal and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that optical modules are tools for converting optical signals into electrical signals. During this conversion process, the information does not change, but the encoding and decoding methods of the information can change.

[0040] 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.

[0041] Figure 2 is a partial structural diagram of a host computer according to some embodiments. To clearly illustrate the connection between the optical module 200 and the host computer 100, Figure 2 only shows the structure of the host computer 100 related to the optical module 200. As shown in Figure 2, the host computer 100 also includes a PCB circuit board 105 disposed within 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 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 raised structures such as fins to increase the heat dissipation area.

[0042] The optical module 200 is inserted into the cage 106 of the host computer 100. The cage 106 secures the optical module 200. Heat generated by the optical module 200 is transferred to the cage 106 and then dissipated through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 connects with the electrical connector inside the cage 106, thereby establishing a bidirectional electrical signal connection between the optical module 200 and the host computer 100. Furthermore, the optical port of the optical module 200 connects to the optical fiber 101, thereby establishing a bidirectional optical signal connection between the optical module 200 and the optical fiber 101.

[0043] Figure 3 is a structural diagram of an optical module according to some embodiments, and Figure 4 is an exploded view of an optical module according to some embodiments. As shown in Figures 3 and 4, the optical module 200 includes a housing, a circuit board 300 disposed within the housing, a light emitting component 400, and a light receiving component 500. However, the present disclosure is not limited thereto. In some embodiments, the optical module 200 includes either the light emitting component 400 or the light receiving component 500.

[0044] The housing includes an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square.

[0045] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicular to the base plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0046] 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.

[0047] The direction of the line connecting the two openings 204 and 205 can be consistent with the length direction of the optical module 200, or it can 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 (the left end in FIG3 ), and the opening 205 is also located at the end of the optical module 200 (the right end in FIG3 ). Alternatively, the opening 204 is located at the end of the optical module 200, and the opening 205 is located on 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 receive an external optical fiber 101, so that the optical fiber 101 connects the optical emitting component 400 and the optical receiving component 500 in the optical module 200.

[0048] The combined assembly of the upper housing 201 and the lower housing 202 facilitates the installation of the circuit board 300, the light emitting component 400, the light receiving component 500, and the like within the housing. The upper housing 201 and the lower housing 202 provide encapsulation and protection for these components. Furthermore, during assembly of the circuit board 300, the light emitting component 400, and the light receiving component 500, the positioning components, heat dissipation components, and electromagnetic shielding components of these components are easily positioned, facilitating automated production.

[0049] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0050] 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.

[0051] For example, the unlocking component 600 is located on the outside of the two lower side panels 2022 of the lower housing 202 and includes a snap-fit ​​component that mates with the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the snap-fit ​​component of the unlocking component 600 secures the optical module 200 in the cage 106. When the unlocking component 600 is pulled, the snap-fit ​​component of the unlocking component 600 moves accordingly, thereby changing the connection between the snap-fit ​​component and the host computer, thereby releasing the optical module 200 from the cage 106 and allowing the optical module 200 to be removed from the cage 106.

[0052] The circuit board 300 includes circuit traces, electronic components, and chips. The electronic components and chips are connected according to the circuit design through the circuit traces to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers, clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0053] 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.

[0054] The circuit board 300 also includes a gold finger 301 formed on its end surface, and 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 set only on the surface of one side of the circuit board 300 (for example, the upper surface shown in Figure 4), or it can be set on the upper and lower surfaces of the circuit board 300 to provide a larger number of pins, thereby adapting to occasions where a large number of pins are required. 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.

[0055] At least one of the light emitting component 400 or the light receiving component 500 is located on a side of the circuit board 300 away from the gold finger 301 .

[0056] In some embodiments, the light emitting component 400 and the light receiving component 500 are physically separated from the circuit board 300 and then electrically connected to the circuit board 300 through corresponding flexible circuit boards or electrical connectors.

[0057] In some embodiments, at least one of the light emitting component or the light receiving component may be directly disposed on the circuit board 300. For example, at least one of the light emitting component or the light receiving component may be disposed on a surface of the circuit board 300 or a side of the circuit board 300.

[0058] In some embodiments, implementing optoelectronic conversion through optical modulation chips, such as silicon photonic chips or thin-film lithium niobate photonic chips, has become a mainstream solution currently used in high-speed optical modules. Light or optical signals can enter and exit the optical modulation chip, which integrates an optical modulator and an optical combiner. For example, light to be modulated, contained in light that does not carry data, enters the optical modulation chip. The optical modulator within the optical modulation chip modulates the light to be modulated to load data into the light to be modulated, thereby generating first modulated light and second modulated light, respectively. The first modulated light and the second modulated light are combined by the optical combiner to generate an optical transmit signal, which is then output from the optical modulation chip.

[0059] In this disclosure, to increase optical transmission power, a semiconductor optical amplifier (SOA) chip can be placed in the output optical path of the light source. This approach only increases optical transmission power to a limited extent. To further increase optical transmission power, the SOA can be integrated within the optical modulation chip. For example, the optical modulation chip is a silicon photonics chip. The SOA is an InP-based optical amplifier. However, integrating an InP-based optical amplifier within a silicon photonics chip is difficult to achieve.

[0060] In the present disclosure, to further increase optical transmit power, first and second modulated lights are output from an optical modulation chip and amplified by optical amplifier structures located outside the optical modulation chip. The amplified first and second modulated lights are then returned to the optical modulation chip and combined within an optical combiner to generate an optical transmit signal, thereby increasing optical transmit power. The optical amplifier structure includes an SOA optical amplifier. Exemplarily, the semiconductor optical amplifier chip is a monolithically integrated SOA chip; alternatively, the semiconductor optical amplifier chip is a hybrid integrated optical amplifier chip.

[0061] In some embodiments, an optical modulator and an optical combiner can be easily integrated within the optical modulation chip. An optical amplification structure is provided outside the optical modulation chip. The optical modulator can modulate the light to be modulated and output a first modulated light and a second modulated light, respectively. Because the optical modulator performs coherent modulation, the polarization states of the first modulated light and the second modulated light are different. Since the SOA optical amplifier is a polarization state device, the optical amplification structure includes a first optical amplifier and a second optical amplifier, respectively. The first optical amplifier amplifies the first modulated light, and the second optical amplifier amplifies the second modulated light. The amplified first and second modulated lights are then transmitted to the optical modulation chip and combined in the optical combiner to generate an optical transmission signal.

[0062] In some embodiments, the optical amplification structure provided outside the optical modulation chip can be a discrete optical device or a hybrid integrated optical chip. The following description takes the optical amplification structure provided outside the optical modulation chip as a discrete optical device as an example.

[0063] In the present disclosure, the optical module may include an optical fiber array, which can transmit the light to be modulated into the optical modulation chip and can also transmit the optical transmission signal generated by the optical modulation chip to the outside.

[0064] The optical module may include an optical modulation chip. The optical modulation chip may include an optical modulator and an optical combiner. The optical modulation chip is electrically connected to the circuit board and coupled to the optical fiber array to receive the modulated light output from the optical fiber array. The optical modulator modulates the modulated light and outputs a first modulated light and a second modulated light, respectively. The first modulated light and the second modulated light have different polarization states.

[0065] The optical module may include a first optical amplifier. Exemplarily, the first optical amplifier may be a monolithically integrated InP-based SOA optical amplifier. The first optical amplifier is disposed externally to the optical modulation chip and in the output optical path of the first modulated light. The first optical amplifier is a polarization device having a preset polarization state for optically amplifying the first modulated light.

[0066] The optical module may include a second optical amplifier. Exemplarily, the second optical amplifier may be a monolithically integrated InP-based SOA optical amplifier. The second optical amplifier is disposed externally to the optical modulation chip and in the output optical path of the second modulated light. The second optical amplifier is a polarization device having a preset polarization state for optically amplifying the second modulated light.

[0067] Since the polarization states of the first modulated light and the second modulated light are different, the polarization states of the first optical amplifier and the second optical amplifier are also different.

[0068] The optical module may include a first reflective surface group. The first reflective surface group is arranged outside the optical modulation chip and is used to return the amplified first modulated light to the optical modulation chip and connect it to the optical combiner.

[0069] The optical module may include a second reflective surface group. The second reflective surface group is arranged outside the optical modulation chip and is used to return the amplified second modulated light to the optical modulation chip and connect it to the optical combiner.

[0070] The amplified first modulated light and the amplified second modulated light are combined in the optical combiner to synthesize an optical transmission signal.

[0071] In some embodiments, the first reflective surface group includes a first reflective surface and a second reflective surface that are opposite to each other.

[0072] The first reflective surface is used to reflect the amplified first modulated light to the second reflective surface. The second reflective surface is used to reflect the amplified first modulated light into the light modulation chip.

[0073] The light incident surface of the first reflective surface faces the first optical amplifier, and the light emitting surface faces the second reflective surface.

[0074] The light incident surface of the second reflective surface faces the first emitting surface, and the light emitting surface faces the light modulation chip.

[0075] Exemplarily, the first reflective surface and the second reflective surface may be a first reflective mirror and a second reflective mirror, respectively.

[0076] In some embodiments, the second reflective surface group includes a third reflective surface and a fourth reflective surface that are opposite to each other. The third reflective surface is configured to reflect the amplified second modulated light to the fourth reflective surface. The fourth reflective surface is configured to reflect the amplified second modulated light output by the optical modulation chip back into the optical modulation chip.

[0077] Exemplarily, the third reflective surface and the fourth reflective surface may be a third reflective mirror and a fourth reflective mirror, respectively.

[0078] The light incident surface of the third reflective surface faces the second optical amplifier, and the light emitting surface faces the fourth reflective surface.

[0079] The light incident surface of the fourth reflective surface faces the third emitting surface, and the light emitting surface faces the light modulation chip.

[0080] In some embodiments, the optical modulation chip includes a first optical port, a second optical port, a third optical port, a fourth optical port, a fifth optical port, a sixth optical port, and a seventh optical port.

[0081] The first optical port is used for coupling with the optical fiber array to transmit the optical transmission signal to the outside.

[0082] The second optical port is used to couple with the optical fiber array to receive the light to be modulated.

[0083] The third optical port is used to couple with the optical fiber array to receive an optical signal from the outside.

[0084] The fourth optical port is coupled to the first optical amplifier to transmit the first modulated light into the first optical amplifier.

[0085] The fifth optical port is coupled to the second optical amplifier to transmit the second modulated light into the second optical amplifier.

[0086] The sixth optical port is coupled to the second reflection surface group to transmit the second modulated light amplified by the second optical amplifier to the optical modulation chip.

[0087] The seventh optical port is coupled to the first reflection surface group to transmit the first modulated light amplified by the first optical amplifier to the optical modulation chip.

[0088] In some embodiments, a first spot mode converter is formed at the first optical port. A second spot mode converter is formed at the second optical port. A third spot mode converter is formed at the third optical port. A fourth spot mode converter is formed at the fourth optical port. A fifth spot mode converter is formed at the fifth optical port. A sixth spot mode converter is formed at the sixth optical port. A seventh spot mode converter is formed at the seventh optical port.

[0089] In the present disclosure, a first optical amplifier and a second optical amplifier are respectively provided on the outside of the optical modulation chip. The optical modulation chip outputs the first modulated light and the second modulated light generated by modulation, respectively, and transmits them to the first optical amplifier and the second optical amplifier, respectively. The first optical amplifier optically amplifies the first modulated light, and transmits the amplified first modulated light to the optical modulation chip through the first reflection surface group, and is connected to the internal optical combiner. The second optical amplifier optically amplifies the second modulated light, and transmits the amplified second modulated light to the optical modulation chip through the second reflection surface group, and is connected to the internal optical combiner. The amplified first modulated light and the amplified second modulated light are combined in the optical combiner to synthesize the optical transmission signal, and output to the outside through the optical fiber array. The present disclosure optically amplifies the first modulated light and the second modulated light by the first optical amplifier and the second optical amplifier, respectively, so as to increase the optical transmission power.

[0090] Figure 5 is a diagram of the optical amplification structure of a coherent optical module provided according to some embodiments of the present disclosure. As shown in Figure 5, in some embodiments, optical modulation chip 1100 does not have its own light source. Instead, optical modulation chip 1100 includes an external light source, which emits light through the side and then enters optical modulation chip 1100. The light source can be a laser box, which encapsulates a laser. The laser generates a laser beam, which is used to transmit laser light to optical modulation chip 1100. Lasers, due to their excellent single-wavelength characteristics and wavelength tuning properties, are the preferred light source for optical modules and even optical fiber transmission. Other types of light, such as LEDs, are generally not used in common optical communication systems. Even if such light sources are used in specific optical communication systems, their light source characteristics and chip components differ significantly from those of lasers. This results in significant technical differences between optical modules using lasers and those using other light sources. Those skilled in the art generally do not believe that these two types of optical modules can provide technical inspiration for each other.

[0091] The light emitted by the light source does not carry data. This data-free light includes the light to be modulated. The light to be modulated enters the optical modulation chip 1100, which modulates it and applies an electrical signal to the light to be modulated, thereby generating light carrying data, i.e., an optical transmit signal, thereby transmitting the optical signal. External light enters the optical modulation chip 1100, which demodulates it and receives the optical signal. Therefore, the optical modulation chip 1100 of the present disclosure integrates optical modulation and demodulation functions. The optical modulation chip 1100 is essentially an optical modulation and demodulation chip. For convenience, the optical modulation and demodulation chip is described as an optical modulation chip.

[0092] In some embodiments, optical modulation chip 1100 may be a silicon photonic chip, which integrates a modulator that can modulate and demodulate optical signals. Because silicon photonic chips are easy to etch, other functional components such as optical splitters, combiners, mixers, and photodetectors can be integrated within them, thereby achieving more functions.

[0093] In some embodiments, the optical modulation chip 1100 may be a thin-film lithium niobate chip. Thin-film lithium niobate exhibits properties such as a linear electro-optic effect. An applied electric field causes a linear change in its refractive index in the corresponding direction, allowing light waves transmitted through the medium to have controllable intensity, phase, and other information. Therefore, thin-film lithium niobate can be selected as the material for the optical modulator to achieve higher modulation efficiency. Furthermore, thin-film lithium niobate chips exhibit low optical loss.

[0094] As shown in Figure 5, in some embodiments, the optical modulation chip 1100 is an example of a silicon photonic chip. When the optical modulation chip 1100 is a silicon photonic chip, an optical demodulator 1120, an optical modulator 1130, and an optical combiner 1140 are integrated therein.

[0095] Exemplarily, light or optical signals enter and exit the optical modulation chip 1100 through the optical fiber array 1300. Exemplarily, light or optical signals may also enter and exit the optical modulation chip 1100 through an end coupler or the like. In this disclosure, the example of light or optical signals entering and exiting the optical modulation chip 1100 through the optical fiber array 1300 is used for illustrative purposes.

[0096] In some embodiments, optical fiber array 1300 includes a first optical fiber ribbon 1311, a second optical fiber ribbon 1312, and a third optical fiber ribbon 1313. First optical fiber ribbon 1311 is used to output the modulated optical transmission signal from optical modulation chip 1100; second optical fiber ribbon 1312 is used to transmit non-data light provided by the light source into optical modulation chip 1100; and third optical fiber ribbon 1313 is used to transmit external optical signals into optical modulation chip 1100.

[0097] The optical fiber array 1300 is coupled to the optical modulation chip 1100. The optical fiber interfaces of the first optical fiber ribbon 1311, the second optical fiber ribbon 1312, and the third optical fiber ribbon 1313 are coupled to corresponding optical ports of the optical modulation chip 1100. The optical ports of the optical modulation chip 1100 coupled to the optical fiber array 1300 include a first optical port, a second optical port, and a third optical port. The first optical port is coupled to the optical fiber interface of the first optical fiber ribbon 1311, the second optical port is coupled to the optical fiber interface of the second optical fiber ribbon 1312, and the third optical port is coupled to the optical fiber interface of the third optical fiber ribbon 1313.

[0098] In some embodiments, the optical fiber array 1300 and the optical modulator chip 1100 are coupled and connected through end-face coupling. During end-face coupling, the end face of the optical fiber array 1300 is coupled to the end face of the optical modulator chip 1100 by focusing, leaving a small gap between the two end faces. After the optical path is focused, optical glue is filled in the small gap to fit the two together, thereby achieving hybrid integration in the horizontal direction. Since the end-face coupling is calibrated separately for each chip, the end-face coupling is beneficial to improving the accuracy of optical coupling. Exemplarily, the end-face coupling between the optical fiber array 1300 and the optical modulator chip 1100 can be coupled by refractive index matching glue. The refractive index matching glue can not only match the refractive index between the optical fiber array 1300 and the optical modulator chip 1100, but also fix the connection between the two after the optical path is aligned.

[0099] In some embodiments, the optical modulation chip 1100 is a silicon photonic chip. For this reason, the mode spot of the single-mode optical fiber in the optical fiber array 1300 is circular and relatively large, while the mode spot of the optical modulation chip 1100 is elliptical and relatively small. Directly coupling the optical fiber array 1300 with the optical modulation chip 1100 will result in significant coupling loss due to the large mode field mismatch. To this end, a corresponding mode spot converter is formed at the optical port end face of the optical modulation chip 1100 to increase the mode spot size of the optical modulation chip 1100, thereby reducing the mode field matching between the optical fiber and the waveguide and improving the optical coupling efficiency. The mode spot converter is a horizontally tapered coupler structure that achieves optical field expansion by gradually varying the waveguide width to match the mode spot of the optical fiber and improve the optical coupling efficiency.

[0100] Exemplarily, a first spot mode converter 1111 is formed at the first optical port of the optical modulation chip 1100, a second spot mode converter 1112 is formed at the second optical port, and a third spot mode converter 1113 is formed at the third optical port. The first spot mode converter 1111 is used to achieve spot mode matching with the first optical fiber ribbon 1311, thereby improving optical coupling efficiency; the second spot mode converter 1112 is used to achieve spot mode matching with the second optical fiber ribbon 1312, thereby improving optical coupling efficiency; and the third spot mode converter 1113 is used to achieve spot mode matching with the third optical fiber ribbon 1313, thereby improving optical coupling efficiency.

[0101] The waveguide widths of the first spot mode converter 1111, the second spot mode converter 1112, and the third spot mode converter 1113 gradually widen toward the optical fiber array 1300. This ensures a larger spot mode when coupled with the optical fiber interface of the optical fiber array 1300, thereby matching the spot mode of the optical fiber and improving optical coupling efficiency. The first spot mode converter 1111 is the spot mode converter corresponding to the output optical port, the second spot mode converter 1112 is the spot mode converter corresponding to the input optical port, and the third spot mode converter 1113 is the spot mode converter corresponding to the input optical port.

[0102] In the present disclosure, non-data-carrying light provided by an external light source enters the second optical port of the optical modulation chip 1100 via the second optical fiber ribbon 1312, and is then transmitted into the optical modulation chip 1100 via the second optical port and the second speckle converter 1112. This non-data-carrying light is split into a first light beam and a second light beam in a predetermined ratio by a built-in optical splitter in the optical modulation chip 1100. The first light beam is transmitted as the light to be modulated to the optical modulator 1130 for modulation, and the second light beam is transmitted as the local oscillator light to the optical demodulator 1120 for demodulation.

[0103] In some embodiments, an external optical signal enters the third optical port of the optical modulation chip 1100 via the third optical fiber ribbon 1313, is transmitted into the optical modulation chip 1100 via the third optical port and the third spot size converter 1113, and is coherently demodulated with the local oscillator light within the optical demodulator 1120. For example, during optical demodulation, the local oscillator light is mixed with the external optical signal in an optical mixer built into the optical modulation chip 1100 to produce an intermediate frequency signal whose frequency, phase, and amplitude vary in the same manner as the external optical signal. The magnitude of the output photocurrent after coherent mixing is proportional to the product of the power of the external optical signal and the power of the local oscillator light. Because the power of the local oscillator light is greater than that of the external optical signal, the output photocurrent after coherent mixing is significantly increased, thereby improving detection sensitivity.

[0104] Figure 6 is a schematic diagram of the structure of an optical modulator provided according to some embodiments of the present disclosure. As shown in Figure 6, in some embodiments, optical modulator 1130 is an IQ modulator based on a Mach-Zehnder modulator (MZM), which can implement high-order modulation and load data onto the modulated light to generate an optical transmit signal. Optical modulator 1130 uses coherent modulation, ultimately outputting two modulated beams with different polarization states.

[0105] The optical modulator 1130 includes a first I modulator 1131, a first Q modulator 1132, a second I modulator 1133, and a second Q modulator 1134. The light to be modulated is converted by the polarization beam splitter 1135 built into the optical modulation chip 1100 into two beams of light with perpendicular polarization directions, namely, TE polarized light and TM polarized light, as shown in Figure 6. The TE polarized light is further split into two beams that enter the first I modulator 1131 and the first Q modulator 1132, respectively; the TM polarized light is further split into two beams that enter the second I modulator 1133 and the second Q modulator 1134, respectively. The first I modulator 1131 and the first Q modulator 1132 perform high-order modulation on the TE polarized light to generate the first modulated light, while the second I modulator 1133 and the second Q modulator 1134 perform high-order modulation on the TM polarized light to generate the second modulated light. The first modulated light and the second modulated light have different polarization states. For example, the polarization directions of the first modulated light and the second modulated light are perpendicular to each other.

[0106] In the present disclosure, the optical emission power of the optical modulation chip 1100 is increased by an optical amplification structure. The optical amplification structure includes an optical amplification chip, such as an SOA optical chip. An optical amplification chip, such as an SOA optical chip, is an active device that uses a III-V mixed material as a gain medium and provides gain to external photons by injecting current. The III-V mixed material is a direct bandgap material with a strong linear electro-optical Pockels effect, which makes it easy to realize the optical amplification function. The III-V mixed material can include III-V materials such as InP, GaAs, and AlGaAs. In some embodiments, the optical amplification chip can be a monolithically integrated InP-based SOA optical amplifier. In some embodiments, the optical amplification chip can be a hybrid integrated optical chip.

[0107] Since the polarization states of the first modulated light and the second modulated light are different, and the SOA optical chip is a polarization state element, the SOA optical chip has polarization characteristics. Polarization characteristics refer to being sensitive to the polarization state of the input light, and producing different gain effects on the gain of input light with different polarization states. For example, when the polarization state of the SOA optical chip is the same as the polarization state of the input light, the gain effect on the input light is more significant. If the first modulated light and the second modulated light generated by the optical modulator 1130 are combined by the optical combiner and then amplified by the SOA optical chip, then since the combined optical signal contains two optical signals with different polarization states, the SOA optical chip produces a more significant gain effect on one of the optical signals and a weaker gain effect on the other optical signal, thereby reducing the gain effect of the SOA optical signal. Therefore, in the present disclosure, the first modulated light and the second modulated light generated by the optical modulator 1130 are optically amplified separately, and then combined and output.

[0108] In some embodiments, an optical amplification structure is positioned external to the optical modulation chip 1100. The first modulated light and the second modulated light generated by the optical modulator 1130 are output separately. The optical amplification structure includes two monolithically integrated InP-based SOA optical amplifiers, such as the first InP-based SOA optical amplifier 1200a and the second InP-based SOA optical amplifier 1200b shown in FIG5 , to optically amplify the first modulated light and the second modulated light, respectively. Both the first InP-based SOA optical amplifier 1200a and the second InP-based SOA optical amplifier 1200b have gain characteristics and polarization characteristics. The gain characteristic refers to the ability of the direct bandgap material to achieve optical amplification, while the polarization characteristic refers to the different gain effects on input light of different polarization states. For example, the InP-based SOA optical amplifier has a stronger gain effect on input light of the same or similar polarization state.

[0109] After being amplified by the first InP-based SOA optical amplifier 1200a and the second InP-based SOA optical amplifier 1200b, the first modulated light and the second modulated light return to the optical modulation chip 1100 and are combined in the optical combiner 1140 to generate an optical transmit signal. The optical transmit signal is sequentially transmitted through the first spot size converter 1111, the first optical port of the optical modulation chip 1100, and the first optical fiber ribbon 1311. Based on the polarization characteristics of the SOA optical amplifier, the first InP-based SOA optical amplifier 1200a has a preset polarization state to optically amplify the first modulated light. Exemplarily, the first InP-based SOA optical amplifier 1200a has a polarization state that is the same as or similar to that of the first modulated light. The second InP-based SOA optical amplifier 1200b has a preset polarization state to optically amplify the second modulated light. Exemplarily, the second InP-based SOA optical amplifier 1200b has a polarization state that is the same as or similar to that of the second modulated light. Since the polarization states of the first modulated light and the second modulated light are different, the polarization states of the first InP-based SOA optical amplifier 1200 a and the second InP-based SOA optical amplifier 1200 b are also different.

[0110] To amplify the first modulated light, a first InP-based SOA optical amplifier 1200a, a reflector 1700a, and a reflector 1700b are disposed in free space outside the optical modulation chip 1100. Reflectors 1700a and 1700b are positioned opposite each other. Reflector 1700a is configured to reflect the first modulated light amplified by the first InP-based SOA optical amplifier 1200a toward reflector 1700b, while reflector 1700b is configured to reflect the received, amplified first modulated light toward the optical modulation chip 1100, thereby returning the amplified first modulated light to the optical modulation chip 1100.

[0111] Among them, since the first modulated light is divergent light when it is output from the optical modulation chip 1100, a converging lens 1200e is provided between the optical modulation chip 1100 and the first InP-based SOA optical amplifier 1200a, and the amplified first modulated light is retransmitted to the optical modulation chip 1100 through the converging lens 1200h to improve the optical coupling efficiency.

[0112] A collimating lens is provided between the first InP-based SOA optical amplifier 1200 a and the reflector 1700 a , so that parallel light enters the reflector 1700 a and is reflected therein, thereby improving optical coupling efficiency.

[0113] To amplify the second modulated light, a second InP-based SOA optical amplifier 1200b, a reflector 1700c, and a reflector 1700d are disposed in free space outside the optical modulation chip 1100. Reflectors 1700c and 1700d are positioned opposite each other. Reflector 1700c is configured to reflect the first modulated light amplified by the second InP-based SOA optical amplifier 1200b toward reflector 1700d. Reflector 1700d is configured to reflect the received, amplified second modulated light toward the optical modulation chip 1100, thereby returning the amplified second modulated light to the optical modulation chip 1100.

[0114] Among them, since the second modulated light is divergent light when it is output from the optical modulation chip 1100, a converging lens 1200f is provided between the optical modulation chip 1100 and the second InP-based SOA optical amplifier 1200b, and the amplified first modulated light is retransmitted to the optical modulation chip 1100 through the converging lens 1200g to improve the optical coupling efficiency.

[0115] A collimating lens is provided between the second InP-based SOA optical amplifier 1200 b and the reflector 1700 c , so that parallel light enters the reflector 1700 c and is reflected therein, thereby improving optical coupling efficiency.

[0116] The reflectors 1700a and 1700c are staggered relative to each other to avoid mutual interference of light paths; the reflectors 1700b and 1700d are staggered relative to each other to avoid mutual interference of light paths.

[0117] Reflectors 1700a and 1700b are arranged on the same axis, tilted, and opposite to each other. The light-incident surface of reflector 1700a faces the first InP-based SOA optical amplifier 1200a, and its light-emitting surface faces reflector 1700b. The light-incident surface of reflector 1700b faces the light-emitting surface of reflector 1700a, and its light-emitting surface faces the end face of the optical modulation chip 1100.

[0118] Reflectors 1700c and 1700d are arranged on the same axis, tilted and facing each other. The light-incident surface of reflector 1700c faces the second InP-based SOA optical amplifier 1200b, and its light-emitting surface faces reflector 1700d. The light-incident surface of reflector 1700d faces the light-emitting surface of reflector 1700c, and its light-emitting surface faces the end face of the optical modulation chip 1100.

[0119] In the present disclosure, the first modulated light is output from the optical modulation chip 1100, coupled to the first InP-based SOA optical amplifier 1200a through the converging lens 1200e, and after being amplified by the first InP-based SOA optical amplifier 1200a, coupled to the surface of the reflector 1700a through the collimating lens; the reflector 1700a reflects the amplified first modulated light toward the reflector 1700b, and the reflector 1700b continues to reflect the amplified first modulated light toward the end face of the optical modulation chip 1100, and re-transmits the amplified first modulated light to the optical modulation chip 1100 through the converging lens 1200h.

[0120] The second modulated light is output from the optical modulation chip 1100, coupled to the second InP-based SOA optical amplifier 1200b through the converging lens 1200f, and after being amplified by the second InP-based SOA optical amplifier 1200b, coupled to the surface of the reflector 1700c through the collimating lens; the reflector 1700c reflects the amplified first modulated light toward the reflector 1700d, and the reflector 1700d continues to reflect the amplified second modulated light toward the end face of the optical modulation chip 1100, and re-transmits the amplified second modulated light to the optical modulation chip 1100 through the converging lens 1200g.

[0121] The first and second modulated lights are output from the optical modulation chip 1100. They are optically amplified outside the optical modulation chip 1100 and then reflected and retransmitted into the optical modulation chip 1100. The amplified first and second modulated lights are then combined within the optical combiner 1140 to form a combined optical transmit signal. The optical transmit signal is then emitted sequentially through the first spot size converter 1111 of the optical modulation chip 1100, the first optical port of the optical modulation chip 1100, and the first optical fiber ribbon 1311 of the optical fiber array 1300.

[0122] In the present disclosure, first InP-based SOA optical amplifier 1200a, second InP-based SOA optical amplifier 1200b, reflectors 1700a, 1700b, 1700c, and 1700d are independently located outside optical modulation chip 1100, thereby amplifying the first modulated light and the second modulated light, respectively, to increase optical transmission power. First InP-based SOA optical amplifier 1200a and second InP-based SOA optical amplifier 1200b form a monolithic integrated optical amplifier chip.

[0123] In some embodiments, the optical amplification structure disposed outside the optical modulation chip may be a discrete optical device or a hybrid integrated optical chip. The following description takes the optical amplification structure disposed outside the optical modulation chip as a hybrid integrated optical chip as an example.

[0124] FIG7 is a schematic diagram of a coupling structure of a hybrid integrated optical amplifier chip and an optical modulation chip according to some embodiments of the present disclosure. As shown in FIG7 , the optical amplifier structure provided outside the optical modulation chip is a hybrid integrated optical chip. The optical amplifier chip is a hybrid integrated optical amplifier chip 1200.

[0125] In some embodiments, the hybrid integrated optical amplifier chip 1200 is an InP / Si hybrid integrated optical amplifier chip. For example, the InP / Si hybrid integrated optical amplifier chip integrates an InP-based SOA optical amplifier and a Si waveguide. InP-based SOA optical amplifiers have excellent gain characteristics due to their material properties. Silicon has low absorption loss and a high refractive index in the optical communication band, which helps reduce transmission loss. Therefore, integrating a silicon waveguide into the hybrid integrated optical amplifier chip 1200 reduces transmission loss and helps increase optical coupling efficiency. Furthermore, silicon waveguides have a smaller bending radius than InP waveguides and are smaller when bent. Therefore, the silicon waveguide can be bent to return the first and second modulated lights output from the optical modulation chip 1100 to the optical modulation chip 1100 through the bent silicon waveguide. The InP / Si hybrid integrated optical amplifier chip disclosed herein can fully utilize the gain characteristics of the InP-based SOA optical amplifier and the low loss characteristics of the silicon waveguide, packaging them together through hybrid integration to form a hybrid integrated optical chip. This hybrid integrated optical chip includes a silicon substrate, which can be integrated with a silicon waveguide to fully utilize the silicon waveguide's low transmission loss and bendability. In this disclosure, integrating both an optical amplifier and a silicon-based waveguide into the same chip can simultaneously leverage the optical amplifier's gain characteristics and the silicon-based waveguide's low transmission loss characteristics.

[0126] Since the polarization states of the first modulated light and the second modulated light are different, and the SOA optical chip is a polarization state element, the SOA optical chip has polarization characteristics. Polarization characteristics refer to sensitivity to the polarization state of the input light, and different gain effects are produced for input lights of different polarization states.

[0127] To amplify the first modulated light and the second modulated light, a first optical amplifying unit and a second optical amplifying unit are formed in the hybrid integrated optical amplifier chip 1200. The first optical amplifying unit amplifies the first modulated light, and the second optical amplifying unit amplifies the second modulated light.

[0128] In some embodiments, the first optical amplification unit includes a first optical amplifier 1210 and a first optical waveguide 1230. The first optical amplifier 1210 and the first optical waveguide 1230 may be made of different materials.

[0129] Exemplarily, the first optical amplifier 1210 is a monolithically integrated InP-based SOA optical amplifier. That is, the first InP-based SOA optical amplifier 1200a in the above embodiment is integrated into the first optical amplification unit. The first optical amplifier 1210 has the same gain characteristics and polarization characteristics as the monolithically integrated InP-based SOA optical amplifier described above.

[0130] For example, the first optical waveguide 1230 may be a silicon-based waveguide, which has low transmission loss.

[0131] The first optical amplifier 1210 has a preset polarization state for optically amplifying the first modulated light. Exemplarily, the first optical amplifier 1210 has a polarization state that is the same as or similar to that of the first modulated light. The first optical waveguide 1230 is bent, with one end of the first optical waveguide 1230 facing the optical port of the optical modulation chip 1100 that outputs the first modulated light, and the other end facing the optical port of the optical modulation chip 1100 that receives the amplified first modulated light. The first modulated light, amplified by the first optical amplifier 1210, returns to the optical modulation chip 1100 along the first optical waveguide 1230. Due to the low transmission loss of silicon waveguides, the first optical waveguide 1230 is used to transmit the first modulated light before and after amplification, thereby reducing transmission loss. Due to the bendability of silicon waveguides, the first optical waveguide 1230 can be used to transmit the first modulated light before and after amplification, thereby eliminating the need for reflectors 1700a and 1700b in the above-described embodiment, thereby increasing chip integration and optical path stability.

[0132] In some embodiments, the second optical amplification unit includes a second optical amplifier 1220 and a second optical waveguide 1250. The second optical amplifier 1220 and the second optical waveguide 1250 may be made of different materials.

[0133] Exemplarily, the second optical amplifier 1220 is a monolithically integrated InP-based SOA optical amplifier. That is, the second InP-based SOA optical amplifier 1200b in the above embodiment is integrated into the second optical amplification unit. The second optical amplifier 1220 has the same gain and polarization characteristics as the monolithically integrated InP-based SOA optical amplifier described above.

[0134] For example, the second optical waveguide 1250 may be a silicon-based waveguide, which has low transmission loss.

[0135] The second optical amplifier 1220 has a preset polarization state for optically amplifying the second modulated light. Exemplarily, the second optical amplifier 1220 has a polarization state that is the same as or similar to that of the second modulated light. Because the polarization states of the first and second modulated lights are different, the polarization states of the first optical amplifier 1210 and the second optical amplifier 1220 are different. The second optical waveguide 1250 is bent, with one end of the second optical waveguide 1250 facing the optical port of the optical modulation chip 1100 that outputs the second modulated light, and the other end facing the optical port of the optical modulation chip 1100 that receives the amplified second modulated light. The second modulated light, amplified by the second optical amplifier 1220, returns to the interior of the optical modulation chip 1100 along the second optical waveguide 1250. Based on the low transmission loss characteristic of silicon waveguides, using the second optical waveguide 1250 to transmit the second modulated light before and after amplification helps reduce transmission loss. Based on the bendable characteristics of silicon waveguides, the second optical waveguide 1250 can be used to transmit the second modulated light before and after amplification, thereby eliminating the reflectors 1700c and 1700d in the above embodiment, which is beneficial to increasing chip integration and optical path stability.

[0136] In this disclosure, the optical modulator chip 1100 is a silicon photonic chip, for example. The optical waveguide within the optical modulator chip 1100 is a silicon waveguide; the hybrid integrated optical amplifier chip 1200 also integrates a silicon waveguide. The modes transmitted within both the optical modulator chip 1100 and the hybrid integrated optical amplifier chip 1200 are silicon waveguide-transmitted modes, resulting in mode field matching. However, the small size of the silicon waveguide-transmitted modes hinders coupling between the optical modulator chip 1100 and the hybrid integrated optical amplifier chip 1200. To address this, a mode spot converter is formed at the coupling optical port of the optical modulator chip 1100 to increase the mode spot size of the silicon waveguide within the optical modulator chip 1100. Since the hybrid integrated optical amplifier chip 1200 incorporates a silicon waveguide with a higher refractive index, a mode spot converter is also formed at its coupling optical port to increase the mode spot size of the silicon waveguide within the hybrid integrated optical amplifier chip 1200. This, in turn, increases the optical coupling efficiency between the optical modulator chip 1100 and the hybrid integrated optical amplifier chip 1200. For the monolithically integrated InP-based SOA optical amplifier, the internal waveguide is an InP optical waveguide. Due to the specific materials of the InP optical waveguide, such as the low refractive index, a spot converter with a larger spot size cannot be formed at the end face of the InP optical waveguide, thereby reducing the optical coupling efficiency between the optical modulation chip 1100 and the monolithically integrated InP-based SOA optical amplifier.

[0137] In the present disclosure, the hybrid integrated optical amplifier chip 1200, compared to a monolithically integrated InP-based SOA optical amplifier, integrates a silicon substrate within the chip, enabling the formation of silicon waveguides and larger spot size converters on the silicon substrate surface. Therefore, compared to a monolithically integrated InP-based SOA optical amplifier, the hybrid integrated optical amplifier chip 1200 can integrate a spot size converter to improve optical coupling efficiency. Furthermore, the chip can utilize the low transmission loss and bendability of silicon waveguides to reduce transmission loss, eliminating the need for discrete reflectors in free space.

[0138] In some embodiments, the optical modulation chip 1100 is provided with a first spot mode converter 1111 at the first optical port, a second spot mode converter 1112 at the second optical port, and a third spot mode converter 1113 at the third optical port to improve the optical coupling efficiency with the optical fiber array 1300. Spot mode converters are also provided at the coupling optical ports between the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200. For example, the optical modulation chip 1100 is provided with a fourth spot mode converter 1114 at the fourth optical port, a fifth spot mode converter 1115 at the fifth optical port, a sixth spot mode converter 1116 at the sixth optical port, and a seventh spot mode converter 1117 at the seventh optical port. The fourth, fifth, sixth, and seventh optical ports are arranged sequentially from top to bottom, and the fourth spot mode converter 1114, fifth spot mode converter 1115, sixth spot mode converter 1116, and seventh spot mode converter 1117 are all located on the same side and arranged sequentially from top to bottom. The “up” and “down” directions are relative up and down directions in FIG. 7 .

[0139] The fourth optical port of optical modulation chip 1100 outputs the first modulated light, the fifth optical port outputs the second modulated light, the sixth optical port inputs the amplified first modulated light, and the seventh optical port inputs the amplified second modulated light. In other words, the first modulated light and the second modulated light are output from optical modulation chip 1100 through the fourth and fifth optical ports, respectively; the amplified first modulated light and the second modulated light are input into optical modulation chip 1100 through the sixth and seventh optical ports, respectively.

[0140] In some embodiments, a first spot size converter 1241 is formed at the first optical port of the hybrid integrated optical amplifier chip 1200, a second spot size converter 1242 is formed at the second optical port, a third spot size converter 1243 is formed at the third optical port, and a fourth spot size converter 1244 is formed at the fourth optical port. The first, second, third, and fourth optical ports of the hybrid integrated optical amplifier chip 1200 are arranged sequentially from top to bottom. The first spot size converter 1241, second, third, and fourth spot size converters 1242, 1243, and 1244 are all arranged on the same side of the hybrid integrated optical amplifier chip 1200 and are arranged sequentially from top to bottom. The "up" and "down" directions refer to the relative up and down directions in Figure 7 . The first and second optical ports of the hybrid integrated optical amplifier chip 1200 are input optical ports, while the third and fourth optical ports are output optical ports.

[0141] The first optical port of the hybrid integrated optical amplifier chip 1200 is used to input the first modulated light, the second optical port is used to input the second modulated light, the third optical port is used to output the amplified first modulated light, and the fourth optical port is used to input the amplified second modulated light. In other words, the first modulated light and the second modulated light output from the optical modulation chip 1100 enter the hybrid integrated optical amplifier chip 1200 through the first and second optical ports of the hybrid integrated optical amplifier chip 1200, respectively. After being amplified by the hybrid integrated optical amplifier chip 1200, the first modulated light and the second modulated light are output through the third and fourth optical ports of the hybrid integrated optical amplifier chip 1200, respectively, and are coupled into the optical modulation chip 1100 for multiplexing in the optical combiner.

[0142] In some embodiments, the fourth spot size converter 1114, the fifth spot size converter 1115, the sixth spot size converter 1116, and the seventh spot size converter 1117 of the optical modulation chip 1100 are coupled to the first spot size converter 1241, the second spot size converter 1242, the third spot size converter 1243, and the fourth spot size converter 1244 of the hybrid integrated optical amplifier chip 1200, respectively. The waveguide widths of the fourth spot size converter 1114 and the first spot size converter 1241 are symmetrically arranged. The waveguide width of the fourth spot size converter 1114 gradually increases along the direction of light transmission, while the waveguide width of the first spot size converter 1241 gradually increases along the direction of light transmission. This maximizes the spot size at the coupling interface, thereby increasing optical coupling efficiency. The waveguide widths of the fifth spot size converter 1115 and the second spot size converter 1242 are similarly arranged. The waveguide widths of the sixth spot size converter 1116 and the third spot size converter 1243 are similarly arranged. The waveguide widths of the seventh spot mode converter 1117 and the fourth spot mode converter 1244 are set in the same manner.

[0143] The first modulated light is transmitted sequentially along the fourth spot converter 1114 and the first spot converter 1241 to the hybrid integrated optical amplifier chip 1200; the second modulated light is transmitted sequentially along the fifth spot converter 1115 and the second spot converter 1242 to the hybrid integrated optical amplifier chip 1200; the first modulated light amplified by the first optical amplifier 1210 is returned to the optical modulation chip 1100 sequentially along the third spot converter 1243 and the sixth spot converter 1116; the second modulated light amplified by the second optical amplifier 1220 is returned to the optical modulation chip 1100 sequentially along the fourth spot converter 1244 and the seventh spot converter 1117 to be combined in the optical combiner.

[0144] In the present disclosure, the first spot converter 1241 and the fourth spot converter 1244 of the hybrid integrated optical amplifier chip 1200 are respectively located at the two ends of the first optical waveguide 1230, and the first spot converter 1241 and the fourth spot converter 1244 are both arranged toward the same end face of the optical modulation chip 1100 through the bending posture of the first optical waveguide 1230; the second spot converter 1242 and the third spot converter 1243 are respectively located at the two ends of the second optical waveguide 1250, and the second spot converter 1242 and the third spot converter 1243 are both arranged toward the same end face of the optical modulation chip 1100 through the bending posture of the second optical waveguide 1250.

[0145] In the present disclosure, the first modulated light output by the optical modulation chip 1100 enters the hybrid integrated optical amplifier chip 1200 along the first spot size converter 1241, is amplified by the first optical amplifier 1210, and then transmitted along the first optical waveguide 1230 to the fourth spot size converter 1244 for output, thereby returning the amplified first modulated light to the optical modulation chip 1100. Therefore, the first optical amplification unit of the hybrid integrated optical amplifier chip 1200 includes the first spot size converter 1241, the first optical amplifier 1210, the first optical waveguide 1230, and the fourth spot size converter 1244. The first spot size converter 1241 and the fourth spot size converter 1244 are located at opposite ends of the first optical waveguide 1230, and the first and fourth spot size converters 1241 and 1244 face the same side due to the bend in the first optical waveguide 1230.

[0146] The second modulated light output by the optical modulation chip 1100 enters the hybrid integrated optical amplifier chip 1200 along the second spot size converter 1242, is amplified by the second optical amplifier 1220, and then transmitted along the second optical waveguide 1250 to the third spot size converter 1243 for output, thereby returning the amplified second modulated light to the optical modulation chip 1100. Therefore, the second optical amplification unit of the hybrid integrated optical amplifier chip 1200 includes the second spot size converter 1242, the second optical amplifier 1220, the second optical waveguide 1250, and the third spot size converter 1243. The second spot size converter 1242 and the third spot size converter 1243 are located at opposite ends of the second optical waveguide 1250, and the bending of the second optical waveguide 1250 ensures that the second spot size converter 1242 and the third spot size converter 1243 face the same side.

[0147] The hybrid integrated optical amplifier chip 1200 provided in the present disclosure integrates a first optical amplifier unit and a second optical amplifier unit to amplify the first modulated light and the second modulated light, respectively. The amplified first and second modulated lights are returned to the optical modulation chip 1100 and combined within the built-in optical combiner 1140. In the present disclosure, because the first and second modulated lights have different polarization states, and the SOA optical amplifier is a polarization state element, the method of optically amplifying the first and second modulated lights separately before combining them ensures that both the first and second modulated lights are amplified, compared to the method of optically amplifying them after combining, thereby increasing the optical transmission power.

[0148] In the present disclosure, placing the optical combiner 1140 within the optical modulation chip 1100 can reduce the difficulty of the hybrid integrated optical amplifier chip 1200 growth process compared to placing the optical combiner 1140 within the hybrid integrated optical amplifier chip 1200. Placing the optical combiner 1140 within the optical modulation chip 1100 is a mature process, so the optical combiner 1140 is placed within the optical modulation chip 1100 as an example.

[0149] As shown in Figure 7, when the hybrid integrated optical amplifier chip 1200 is packaged in an optical module, the hybrid integrated optical amplifier chip 1200 and the optical modulation chip 1100 can be packaged together through end-face coupling. In some embodiments, refractive index matching adhesive can be used to achieve end-face coupling between the end faces of the hybrid integrated optical amplifier chip 1200 and the optical modulation chip 1100. The hybrid integrated optical amplifier chip 1200 and the optical fiber array 1300 are placed on the same side of the optical modulation chip 1100 to optimize the optical path design. Specific packaging implementations will be described in detail later.

[0150] Figure 8 is a schematic diagram of another coupling structure between a hybrid integrated optical amplifier chip and an optical modulation chip, according to some embodiments of the present disclosure. As shown in Figure 8, in some embodiments, when the hybrid integrated optical amplifier chip 1200 is packaged in an optical module, a lens array 1500 can be used to package the hybrid integrated optical amplifier chip 1200 and the optical modulation chip 1100. For example, the lens array 1500 is positioned between the hybrid integrated optical amplifier chip 1200 and the optical modulation chip 1100, and the hybrid integrated optical amplifier chip 1200 and the optical fiber array 1300 are positioned on the same side of the optical modulation chip 1100 to optimize the optical path design. Specific packaging implementations will be described in detail later.

[0151] Figure 9 is a schematic diagram of the structure of a first optical amplification unit in a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure. As shown in Figure 9, in some embodiments, the hybrid integrated optical amplifier chip 1200 includes a first optical amplification unit and a second optical amplification unit to respectively amplify the first modulated light and the second modulated light output by the optical modulation chip 1100. The first optical amplification unit and the second optical amplification unit have the same structure, respectively including a first optical amplifier 1210 and a second optical amplifier 1220. The first optical amplifier 1210 and the second optical amplifier 1220 have different polarization states to respectively amplify the first modulated light and the second modulated light.

[0152] The first optical amplification unit of the hybrid integrated optical amplifier chip 1200 includes a first spot mode converter 1241, a first optical amplifier 1210, a first optical waveguide 1230, and a fourth spot mode converter 1244. The first spot mode converter 1241 and the fourth spot mode converter 1244 are respectively located at the two ends of the first optical waveguide 1230, and the first optical waveguide 1230 is bent so that the first spot mode converter 1241 and the fourth spot mode converter 1244 are both facing the same side.

[0153] To ensure that the first modulated light can be transmitted into the first optical amplifier 1210, the first optical amplifier 1210 is mounted above the first optical waveguide 1230, and the silicon waveguide below the first optical amplifier 1210 is a disconnected silicon waveguide segment, ensuring that the first modulated light can be transmitted into the first optical amplifier 1210. For example, the first modulated light is coupled vertically upward along the first optical waveguide 1230 into the first optical amplifier 1210, amplified by the first optical amplifier 1210, and then vertically coupled downward along the first optical amplifier 1210 into the first optical waveguide 1230. The amplified first modulated light continues to be transmitted to the fourth spot converter 1244 and output, thereby returning the amplified first modulated light to the optical modulation chip 1100. It is understood that the second optical amplification unit adopts the same structural design as the first optical amplification unit.

[0154] In the present disclosure, first modulated light and second modulated light are respectively output from an optical modulation chip and transmitted to a hybrid integrated optical amplifier chip. The first optical amplifier and the second optical amplifier in the hybrid integrated optical amplifier chip optically amplify the first modulated light and the second modulated light respectively. The amplified first modulated light then returns to the optical modulation chip along a first optical waveguide and is combined in an optical combiner. The amplified second modulated light returns to the optical modulation chip along a second optical waveguide and is combined in the optical combiner to generate an optical transmission signal. The optical transmission signal is output from the optical modulation chip and transmitted along an optical fiber array.

[0155] In the present disclosure, a hybrid integrated optical amplifier chip 1200 integrates a first optical amplifier 1210 and a second optical amplifier 1220 to amplify the first modulated light and the second modulated light, respectively, to improve optical amplification efficiency. A first optical waveguide 1230 and a second optical waveguide 1250 are integrated within the hybrid integrated optical amplifier chip 1200 to return the amplified first modulated light and the second modulated light to the optical modulation chip 1100, respectively. In the present disclosure, integrating both the optical amplifier and the silicon-based waveguide within the same chip leverages both the gain characteristics of the optical amplifier and the low transmission loss characteristics of the silicon-based waveguide. The integration of the optical amplification path and the return transmission path within the same chip ensures optical path stability. Furthermore, integrating all components within the same chip increases coupling efficiency with the optical modulation chip 1100.

[0156] In some embodiments, the hybrid integrated optical amplifier chip 1200 is an InP / Si hybrid integrated optical amplifier chip. The substrate of the hybrid integrated optical amplifier chip 1200 is a silicon substrate, and the optical amplifier integrated in the hybrid integrated optical amplifier chip 1200 is a monolithically integrated InP-based SOA optical amplifier. For example, the monolithically integrated InP-based SOA optical amplifier is inverted on the surface of the silicon substrate. The optical waveguide integrated in the hybrid integrated optical amplifier chip 1200 is a Si-based waveguide. The spot size converter integrated in the hybrid integrated optical amplifier chip 1200 is a Si-based spot size converter.

[0157] Figure 10 is a schematic diagram of the assembly relationship of a circuit board and a substrate provided according to some embodiments of the present disclosure. As shown in Figure 10, a notch 302 is formed on the surface of the circuit board 300, and the substrate 900 is embedded in the notch 302, thereby fixing the substrate 900 to the surface of the circuit board 300. The substrate 900 plays a role in heat dissipation. Exemplarily, the substrate 900 can be a tungsten copper substrate, which is conducive to better heat dissipation. The surface of the substrate 900 also plays a supporting role. The bottom surface of the substrate 900 is exposed relative to the circuit board 300, and the bottom surface of the substrate 900 has a certain thickness to enhance the supporting effect of the substrate 900.

[0158] Exemplarily, an optical modulation chip 1100 , a hybrid integrated optical amplifier chip 1200 and an optical fiber array 1300 are respectively provided on the upper surface of the substrate 900 .

[0159] Figure 11 illustrates a first packaging structure for an optical module according to some embodiments of the present disclosure; Figure 12 illustrates a second packaging structure for an optical module according to some embodiments of the present disclosure. As shown in Figures 11 and 12, the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200 are coupled via end-face coupling. For example, the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200 are end-face coupled using a refractive index matching adhesive to improve optical coupling efficiency.

[0160] In some embodiments, the notch 302 of the circuit board 300 overlaps the surface of the substrate 900, thereby achieving a fixed connection between the circuit board 300 and the substrate 900. The optical modulation chip 1100, the hybrid integrated optical amplifier chip 1200, and the optical fiber array 1300 are all disposed on the surface of the substrate 900, with the hybrid integrated optical amplifier chip 1200 and the optical fiber array 1300 disposed on the same side of the optical modulation chip 1100. The surface of the substrate 900 is sunken relative to the surface of the circuit board 300 so that the surface of the optical modulation chip 1100 is flush with the surface of the circuit board 300.

[0161] In some embodiments, the hybrid integrated optical amplifier chip 1200 generates significant heat during operation. Therefore, a heat sink 1400 is provided on the surface of the hybrid integrated optical amplifier chip 1200. For example, because the upper housing 201 of the optical module has a good heat dissipation channel, the heat sink 1400 is thermally connected to the upper housing 201 of the optical module, thereby transferring the heat generated by the hybrid integrated optical amplifier chip 1200 upward along the heat sink 1400 to the upper housing 201 of the optical module, where it is then dissipated, ensuring the normal operation of the hybrid integrated optical amplifier chip 1200.

[0162] Figure 13 is another packaging structure diagram of an optical module provided according to some embodiments of the present disclosure; Figure 14 is another packaging structure diagram of an optical module provided according to some embodiments of the present disclosure; Figure 15 is another packaging structure diagram of an optical module provided according to some embodiments of the present disclosure. As shown in Figures 13-15, the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200 are coupled to each other via a lens array. For example, a lens array 1500 is provided between the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200, and the lens array 1500 is used to achieve coupling between the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200.

[0163] In some embodiments, the notch 302 of the circuit board 300 similarly overlaps the surface of the substrate 900, thereby achieving a fixed connection between the circuit board 300 and the substrate 900. The optical modulation chip 1100, the hybrid integrated optical amplifier chip 1200, the optical fiber array 1300, and the lens array 1500 are all disposed on the surface of the substrate 900, with the hybrid integrated optical amplifier chip 1200, the optical fiber array 1300, and the lens array 1500 all being located on the same side of the optical modulation chip 1100. The surface of the substrate 900 is sunken relative to the surface of the circuit board 300 so that the surface of the optical modulation chip 1100 is flush with the surface of the circuit board 300.

[0164] In some embodiments, in order to conduct away the heat generated by the hybrid integrated optical amplifier chip 1200 during operation, a TEC 1600 is provided on the surface of the substrate 900 , and the hybrid integrated optical amplifier chip 1200 is placed on the surface of the TEC 1600 . The heat generated by the hybrid integrated optical amplifier chip 1200 is conducted away by providing a cold surface of the TEC 1600 , thereby ensuring the normal operation of the hybrid integrated optical amplifier chip 1200 .

[0165] For example, the hybrid integrated optical amplifier chip 1200 is pre-attached to the surface of the TEC 1600 using optical adhesive. Since the hybrid integrated optical amplifier chip 1200 and the TEC 1600 are already fixed together, end-face coupling with the optical modulation chip 1100 is unsuitable. Therefore, the optical modulation chip 1100 and the hybrid integrated optical amplifier chip 1200 are coupled together using the lens array 1500.

[0166] FIG16 is a diagram illustrating a package structure for end-face coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure; FIG17 is an exploded view illustrating an end-face coupling between an optical modulation chip and a hybrid integrated optical amplifier chip according to some embodiments of the present disclosure. As shown in FIG16 and FIG17 , in some embodiments, a notch 302 is formed on the surface of the circuit board 300. A bearing surface 910 and a lap joint 920 are formed on the surface of the substrate 900. The lap joint 920 is disposed along the periphery of the bearing surface 910, and a height difference is formed between the bearing surface 910 and the lap joint 920. This height difference can be used to support the circuit board 300. Exemplarily, the surface of the lap joint 920 is lower than the surface of the bearing surface 910. Exemplarily, the periphery of the notch 302 overlaps the surface of the lap joint 920, thereby securing the circuit board 300 to the substrate 900.

[0167] The optical modulation chip 1100, the hybrid integrated optical amplifier chip 1200, and the optical fiber array 1300 are respectively disposed on the surface of the support surface 910. The surface of the lap joint 920 is lower than the surface of the support surface 910, so that the surfaces of the optical modulation chip 1100, the hybrid integrated optical amplifier chip 1200, and the optical fiber array 1300 can be flush with the surface of the circuit board 300.

[0168] In some embodiments, a heat sink 1400 is provided on the surface of the hybrid integrated optical amplifier chip 1200. For example, the heat sink 1400 is provided on the top surface of the hybrid integrated optical amplifier chip 1200. The heat sink 1400 is thermally connected to the upper housing 201 of the optical module, thereby transferring heat generated by the hybrid integrated optical amplifier chip 1200 upward along the heat sink 1400 to the upper housing 201 of the optical module and then conducting the heat away, thereby ensuring the normal operation of the hybrid integrated optical amplifier chip 1200.

[0169] Figure 18 is an exploded view of a lens-coupled package between an optical modulation chip and a hybrid integrated optical amplifier chip, according to some embodiments of the present disclosure. Figure 19 is a diagram of a package structure between a substrate, an optical modulation chip, and a hybrid integrated optical amplifier chip, according to some embodiments of the present disclosure. Figure 20 is an exploded view of a package structure between a substrate, an optical modulation chip, and a hybrid integrated optical amplifier chip, according to some embodiments of the present disclosure. As shown in Figures 18-20, a notch 302 is formed on the surface of the circuit board 300. The surface of the substrate 900 is respectively formed with a bearing surface 910, a lap joint surface 920, and a recessed surface 930. The surface of the lap joint surface 920 is lower than the surface of the bearing surface 910. Exemplarily, the periphery of the notch 302 overlaps the surface of the lap joint surface 920, thereby securing the circuit board 300 to the substrate 900. The surface of the bearing surface 910 is respectively provided with an optical modulation chip 1100, an optical fiber array 1300, and a lens array 1500. When the hybrid integrated optical amplifier chip 1200 is placed on the surface of the TEC 1600, the recessed surface 930 is used to position the TEC 1600. For example, the TEC 1600 is placed within the recessed surface 930, and then the hybrid integrated optical amplifier chip 1200 is placed on the surface of the TEC 1600. Because the TEC 1600 has a certain height, placing the TEC 1600 within the recessed surface 930 allows the TEC 1600 to be sunken. This ensures that the hybrid integrated optical amplifier chip 1200 located on the surface of the TEC 1600 is flush with the surface of the circuit board 300, ensuring shorter bonding wires.

[0170] In some embodiments, the optical fiber array 1300 and the lens array 1500 are located at different positions on the same cross section of the optical modulation chip 1100. The hybrid integrated optical amplifier chip 1200 is disposed on the transmission optical path of the lens array 1500. The optical fiber array 1300 includes an optical fiber array substrate 1310 and an optical fiber ribbon 1320.

[0171] Figure 21 is a top view of a package that couples an optical modulation chip with a hybrid integrated optical amplifier chip, according to some embodiments of the present disclosure. As shown in Figure 21 , in some embodiments, an optical modulation chip 1100, a hybrid integrated optical amplifier chip 1200, and an optical fiber array 1300 are each disposed on a surface of a substrate 900. Hybrid integrated optical amplifier chip 1200 and optical fiber array 1300 are disposed on the same side of optical modulation chip 1100.

[0172] The hybrid integrated optical amplifier chip 1200 and the optical modulation chip 1100 are coupled via end-face coupling; the optical fiber array 1300 and the optical modulation chip 1100 are also connected via end-face coupling.

[0173] Figure 22 is a top view of a package that includes a lens coupling between an optical modulation chip and a hybrid integrated optical amplifier chip, according to some embodiments of the present disclosure. As shown in Figure 22 , in some embodiments, an optical modulation chip 1100, a hybrid integrated optical amplifier chip 1200, an optical fiber array 1300, and a lens array 1500 are each disposed on a surface of a substrate 900. Hybrid integrated optical amplifier chip 1200, optical fiber array 1300, and lens array 1500 are disposed on the same side of optical modulation chip 1100.

[0174] The hybrid integrated optical amplifier chip 1200 and the optical modulation chip 1100 are coupled via the lens array 1500 ; the optical fiber array 1300 and the optical modulation chip 1100 are connected via end-face coupling.

[0175] Figure 23 is a schematic diagram of the optical path corresponding to a coupling method between an optical modulation chip and a hybrid integrated optical amplifier chip in an optical module according to some embodiments of the present disclosure. As shown in Figure 23, optical modulation chip 1100 and hybrid integrated optical amplifier chip 1200 are coupled via end-face coupling; optical fiber array 1300 is also connected to optical modulation chip 1100 via end-face coupling.

[0176] The light emitted by the light source is light that does not carry data. This light that does not carry data is transmitted to the optical modulation chip 1100 via the second optical fiber ribbon 1312 of the optical fiber array 1300. The optical splitter built into the optical modulation chip 1100 splits the light into a first light split and a second light split in a certain proportion. The first light split is transmitted to the optical modulator 1130 as the light to be modulated for modulation, and the second light split is transmitted to the optical demodulator 1120 as the local oscillator light for demodulation. The first light split is transmitted to the optical modulator 1130, which modulates the first light split and outputs the first modulated light and the second modulated light, respectively. The first modulated light and the second modulated light are coupled along the first optical port and the second optical port of the optical modulation chip 1100 and transmitted to the hybrid integrated optical amplifier chip 1200, and are optically amplified by the first optical amplifier 1210 and the second optical amplifier 1220, respectively. The first modulated light amplified by the first optical amplifier 1210 returns to the optical modulation chip 1100 along the first optical waveguide and the third optical port of the optical modulation chip 1100. The second modulated light amplified by the second optical amplifier 1220 returns to the optical modulation chip 1100 along the second optical waveguide and the fourth optical port of the optical modulation chip 1100. The light is then combined by the optical combiner 1140 built into the optical modulation chip 1100 and transmitted through the first optical fiber ribbon 1311 of the optical fiber array 1300.

[0177] The external optical signal is transmitted to the optical demodulator 1120 built into the optical modulation chip 1100 via the third optical fiber ribbon 1313 of the optical fiber array 1300 , and is coherently demodulated together with the second split light.

[0178] Figure 24 is a schematic diagram of the optical path corresponding to another coupling method between an optical modulation chip and a hybrid integrated optical amplifier chip in an optical module according to some embodiments of the present disclosure. As shown in Figure 24, optical modulation chip 1100 and hybrid integrated optical amplifier chip 1200 are coupled via lens array 1500; optical fiber array 1300 and optical modulation chip 1100 are also connected via end-face coupling.

[0179] The light emitted by the light source does not carry data. This data-free light is transmitted to the optical modulator chip 1100 via the second optical fiber ribbon 1312 of the optical fiber array 1300. The optical splitter built into the optical modulator chip 1100 splits the light into a first light split and a second light split in a certain ratio. The first light split is transmitted to the optical modulator 1130 as the light to be modulated for modulation, and the second light split is transmitted to the optical demodulator 1120 as the local oscillator light for demodulation. The first light split is transmitted to the optical modulator 1130, which modulates the first light split and outputs the first modulated light and the second modulated light, respectively. The first modulated light and the second modulated light are output along the first optical port and the second optical port of the optical modulator chip 1100, respectively, and are coupled through the lens array 1500 and transmitted to the hybrid integrated optical amplifier chip 1200, where they are amplified by the first optical amplifier 1210 and the second optical amplifier 1220, respectively. After being amplified by the first optical amplifier 1210, the first modulated light is output along the first optical waveguide, coupled into the optical modulation chip 1100 through the lens array 1500, and returned to the optical modulation chip 1100 through the third optical port of the optical modulation chip 1100. After being amplified by the second optical amplifier 1220, the second modulated light is output along the second optical waveguide, coupled into the optical modulation chip 1100 through the lens array 1500, and returned to the optical modulation chip 1100 through the fourth optical port of the optical modulation chip 1100. The light is then combined by the optical combiner 1140 built into the optical modulation chip 1100 and transmitted through the first optical fiber ribbon 1311 of the optical fiber array 1300.

[0180] The external optical signal is transmitted to the optical demodulator 1120 built into the optical modulation chip 1100 via the third optical fiber ribbon 1313 of the optical fiber array 1300 , and is coherently demodulated together with the second split light.

[0181] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. An optical module, characterized in that: include: A circuit board having a notch on its surface; a substrate connected to the circuit board through the notch; An optical fiber array is provided on the surface of the substrate and is used to transmit the light to be modulated and the modulated light after multiplexing; an optical modulation chip, disposed on the surface of the substrate and coupled to the optical fiber array, for receiving the light to be modulated output by the optical fiber array, wherein the optical modulation chip is internally integrated with an optical modulator and an optical combiner, wherein the optical modulator is configured to modulate the light to be modulated and output a first modulated light and a second modulated light, respectively, wherein the first modulated light and the second modulated light have different polarization states; a hybrid integrated optical amplifier chip, disposed on the surface of the substrate and coupled to the optical modulation chip, wherein the hybrid integrated optical amplifier chip respectively integrates a first optical amplifier, a second optical amplifier, a first optical waveguide optically connected to the first optical amplifier, and a second optical waveguide optically connected to the second optical amplifier; wherein the first optical amplifier and the second optical amplifier are both polarization state devices, the first optical amplifier having a first preset polarization state to optically amplify the first modulated light output by the optical modulation chip, and the second optical amplifier having a second preset polarization state to optically amplify the second modulated light output by the optical modulation chip; The first optical waveguide is used to return the amplified first modulated light to the optical modulation chip and connect it to the optical combiner. The second optical waveguide is used to return the amplified first modulated light to the optical modulation chip and connect it to the optical combiner. The amplified first modulated light and the amplified second modulated light are combined in the optical combiner.

2. The optical module according to claim 1, wherein The optical fiber array and the hybrid integrated optical amplifier chip are respectively arranged on the same side of the optical modulation chip; the optical fiber array and the hybrid integrated optical amplifier chip are respectively connected to the optical modulation chip through end face coupling.

3. The optical module according to claim 1, wherein: The optical fiber array and the hybrid integrated optical amplifier chip are respectively arranged on the same side of the optical modulation chip; the optical fiber array and the optical modulation chip are coupled to each other through end face coupling; A semiconductor cooler is provided on the surface of the substrate, the hybrid integrated optical amplifier chip is provided on the surface of the semiconductor cooler, and the hybrid integrated optical amplifier chip is coupled to the optical modulation chip via a lens.

4. The optical module according to claim 1, wherein: A spot size converter is formed at the optical port of the optical modulation chip, and a spot size converter corresponding to the spot size converter at the optical port of the optical modulation chip is formed at the optical port of the hybrid integrated optical amplifier chip.

5. The optical module according to claim 1, wherein: The hybrid integrated optical amplifier chip includes a first optical amplifier unit and a second optical amplifier unit; the first optical amplifier unit is used to receive the first modulated light, optically amplify the first modulated light, and return the light to the optical modulation chip for multiplexing; the second optical amplifier unit is used to receive the second modulated light, optically amplify the second modulated light, and return the light to the optical modulation chip for multiplexing; one end of the first optical amplifier unit is coupled to the output optical port of the optical modulation chip, and the other end is coupled to the input optical port of the optical modulation chip; One end of the second optical amplifying unit is coupled to the output optical port of the optical modulation chip, and the other end is coupled to the input optical port of the optical modulation chip; the first optical amplifying unit includes the first optical waveguide and the first optical amplifier arranged above the first optical waveguide, wherein both ends of the first optical waveguide are connected to a mode spot converter; the first optical waveguide and the first optical amplifier are made of different materials; the second optical amplifying unit includes the second optical waveguide and the second optical amplifier arranged above the second optical waveguide, wherein both ends of the second optical waveguide are connected to a mode spot converter; the second optical waveguide and the second optical amplifier are made of different materials.

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