An optical transmit engine based on an eight-wavelength multiplexing architecture

Abstract

The application discloses an optical transmitting engine based on an eight-wavelength multiplexing architecture, comprising: an external laser for providing eight different wavelength light sources; an optical wavelength modulation unit, a total of eight, each unit comprising two Mach-Zehnder modulators, the modulators being configured to divide the input light signal of the corresponding wavelength into two independent modulation channels through Y branching; wherein each modulation channel is allocated a different wavelength; a wavelength division multiplexing unit comprising a plurality of wavelength division multiplexers for multiplexing the optical signals of all modulation channels; an output interface unit for outputting the combined optical signal to an optical fiber; a driving and control unit for providing electrical driving signals and system control. In this scheme, the external laser is directly coupled through a fiber array, successfully solving the key bottleneck of the built-in scheme, combined with the eight-wavelength multiplexing scheme, providing a single-port 3.2Tbps optical transmitting engine with high performance, high stability, easy maintenance and facing the future.

Description

Technical Field

[0001] This solution relates to the field of optical communication data transmission technology, and in particular to an optical transmission engine based on an eight-wavelength multiplexing architecture. Background Technology

[0002] With the continuous development of data centers, cloud computing, and high-performance computing applications, the demand for network transmission bandwidth is growing exponentially, driving optical interconnect technology towards the Tbps level per port. Currently, most mainstream 800G optical modules in the industry adopt a four-wavelength wavelength division multiplexing architecture, combined with the PAM4 modulation format, enabling each wavelength channel to achieve a rate of 200Gbps, thereby achieving a total transmission capacity of 800Gbps on a single optical fiber.

[0003] However, when the target rate is increased to 1.6Tbps or even 3.2Tbps, the existing architecture faces severe challenges in terms of channel scalability, modulation bandwidth, integration density and power consumption control.

[0004] In existing photonic integrated emission engine solutions, multiple discrete laser chips are typically integrated into the same module. These solutions generally use four lasers of different wavelengths, each of which is split into two paths by an optical splitter to drive two silicon-based Mach-Zehnder modulators. Finally, the signals are combined by a wavelength division multiplexer and output through two optical fibers. This traditional architecture has several significant drawbacks: First, the built-in laser introduces significant power consumption and heat, and the resulting temperature rise can easily lead to an increase in the temperature of the entire optical engine, affecting not only the performance stability of the modulator and passive devices but also potentially causing reliability risks. Second, optical coupling between the laser and the optical waveguide requires multiple sets of lenses and polarization-independent isolators, resulting in a large number of optical components, complex structure, and cumbersome assembly processes. Furthermore, gaps for preventing glue overflow between components are required, increasing the packaging size and cost. In addition, lasers in traditional solutions often lack independent and precise thermal control and wavelength tuning mechanisms, making them prone to wavelength drift under ambient temperature fluctuations, which in turn affects the channel isolation and long-term operational stability of the wavelength division multiplexing system. Finally, with a built-in laser, if a single laser fails, the entire optical engine module often needs to be replaced, resulting in high maintenance costs and a lack of repairability.

[0005] Therefore, in view of the problems of thermal management difficulties, complex coupling structure, insufficient wavelength stability and high maintenance cost caused by the built-in laser in the above-mentioned existing technologies, there is an urgent need to propose a new optical emission engine architecture. Summary of the Invention

[0006] This solution aims to at least address the technical problems existing in the prior art. To this end, the first aspect of this invention proposes an optical emission engine based on an eight-wavelength multiplexing architecture, comprising: An external laser is used to provide light sources of eight different wavelengths; There are 8 optical wavelength modulation units. Each optical wavelength modulation unit includes two Mach-Zehnder modulators. The Mach-Zehnder modulators are configured via Y-branch to divide the input optical signal of the corresponding wavelength into two independent modulation channels. Each modulation channel is assigned a different wavelength, and each modulation channel supports data transmission in PAM4 modulation format. A wavelength division multiplexing unit, comprising multiple wavelength division multiplexers, is used to multiplex the optical signals of all modulation channels; The output interface unit is used to output the combined optical signal to the optical fiber; Drive and control unit, used to provide electric drive signals and system control.

[0007] Optionally, the external laser is an integrated eight-wavelength array laser, and the external laser is coupled to the optical input end of the Mach-Zehnder modulator through an eight-channel polarization-maintaining fiber; the eight-channel polarization-maintaining fiber is positioned using a high-precision V-groove and fixed using UV-curable adhesive.

[0008] Optionally, the substrate of each laser channel of the eight-wavelength array laser is provided with a boss structure to achieve thermal isolation; each laser channel integrates a thermoelectric cooler, which, together with a high-precision temperature sensor and PID control circuit, enables independent wavelength tuning.

[0009] Optionally, the Mach-Zehnder modulator is based on silicon-based or thin-film lithium niobate material, manufactured using CMOS-compatible technology, with a modulation bandwidth of not less than 67 GHz and an insertion loss of not more than 3 dB.

[0010] Optionally, the modulator chip integrates a PCB buried copper process on the back, which is beneficial for heat dissipation. Combined with a local temperature sensor, the operating temperature is stabilized within ±0.1℃ of the set value.

[0011] Optionally, the optical input port and optical output port of the Mach-Zehnder modulator are respectively provided with directional couplers, through which 1% to 5% of the optical power is split and coupled to a photodetector integrated on the chip. The photodetector is used to monitor the optical power and coupling status in real time, and the monitoring data is uploaded to the control unit through the I2C interface.

[0012] Optionally, the external laser is a distributed feedback laser array, with each laser outputting a wavelength that follows the LWDM protocol, the eight wavelengths spaced at 800 GHz, and the wavelength range being the O-band.

[0013] Optionally, the driving circuit corresponding to the PAM4 modulation includes a pre-emphasis equalization module and uses a 7th-order feedforward equalization algorithm for channel loss compensation.

[0014] Optionally, the wavelength division multiplexing unit includes three cascaded interferometric wavelength division multiplexer chips, each of which is composed of a multimode interference coupler; the chips are made of low-loss silicon nitride material and have an insertion loss of less than 1.5dB.

[0015] Optionally, the output of the wavelength division multiplexer chip is coupled to an output optical fiber, and the two output optical fibers are connected to an MPO connector, with each output optical fiber transmitting a high-speed optical signal of 8 wavelengths.

[0016] The embodiments of the present invention have the following beneficial effects: The optical emission engine based on an eight-wavelength multiplexing architecture provided in this invention includes: an external laser for providing eight different wavelengths of light source; eight optical wavelength modulation units, each comprising two Mach-Zehnder modulators configured via a Y-branch to divide the input optical signal of the corresponding wavelength into two independent modulation channels; wherein each modulation channel is assigned a different wavelength, and each modulation channel supports PAM4 modulation format data transmission; a wavelength division multiplexing unit including multiple wavelength division multiplexers for multiplexing the optical signals of all modulation channels; an output interface unit for outputting the multiplexed optical signal to an optical fiber; and a drive and control unit for providing electrical drive signals and system control. In this solution, the external laser is directly coupled through an optical fiber array, successfully solving the key bottleneck of the built-in solution. Combined with the eight-wavelength multiplexing scheme, it provides a high-performance, highly stable, easy-to-maintain, and future-oriented single-port 3.2Tbps optical emission engine. Attached Figure Description

[0017] Figure 1 A structural diagram of an optical emission engine based on an eight-wavelength multiplexing architecture is provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of an external laser substrate boss design provided in an embodiment of the present invention; Figure 3 A schematic diagram of a modulator input-output coupling monitoring design provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a cascaded architecture design provided for an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present solution, and not all embodiments. Based on the embodiments of the present solution, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present solution.

[0019] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, the use of "based on" or "according to" implies openness and inclusiveness, because processes, steps, calculations, or other actions "based on" or "according to" one or more of the stated conditions or values ​​may in practice be based on additional conditions or beyond the stated values.

[0020] Figure 1 This is a structural diagram of an optical emission engine based on an eight-wavelength multiplexing architecture, provided as an embodiment of the present invention.

[0021] like Figure 1 As shown, the light-emitting engine includes: External laser 1 is used to provide light sources of 8 different wavelengths; There are 8 optical wavelength modulation units 2. Each optical wavelength modulation unit includes two Mach-Zehnder modulators 21. The Mach-Zehnder modulators 21 are configured through a Y branch 22 to divide the input optical signal of the corresponding wavelength into two independent modulation channels. Each modulation channel is assigned a different wavelength, and each modulation channel supports data transmission in PAM4 modulation format. The wavelength division multiplexing unit (Mux) 3 is used to multiplex the optical signals of all modulation channels to achieve a total output rate of 3.2Tbps per port. Output interface unit (MPO) 4 is used to output the combined optical signal to the optical fiber; The drive and control unit (not shown in the figure) is used to provide electric drive signals and system control.

[0022] In this embodiment of the invention, an external laser is responsible for outputting lasers of 8 different wavelengths, each beam of light corresponding to an independent transmission channel.

[0023] The system has eight identical optical wavelength modulation units, each responsible for processing a specific wavelength. Each modulation unit integrates two Mach-Zehnder modulators (MZMs). Each Mach-Zehnder modulator splits an input optical signal into two independent modulation channels via a Y-branch. Thus, with eight wavelengths × two channels, a total of 16 independent modulation channels are achieved.

[0024] Each modulation channel supports data transmission in PAM4 (Pulse Amplitude Modulation) format. PAM4 carries information using four levels (00, 01, 10, 11), which is equivalent to transmitting 2 bits of data in one symbol period, thus doubling the transmission rate with the same bandwidth.

[0025] The Mach-Zehnder modulator employs a carrier depletion-type PN junction modulation structure with a multi-stage cascaded modulation electrode design, achieving a modulation bandwidth of at least 67 GHz. The optical waveguide is based on a 220 nm thick silicon layer with a width of 450 nm, ensuring single-mode transmission. Modulation method: Each Mach-Zehnder modulator splits the input light into two independent channels via a 3 dB directional coupler. Each channel supports PAM4 modulation format, with a data transmission rate of 200 Gbps. The modulator bias point is locked at the quadrature operating point by fine-tuning the DC bias voltage, with a drive voltage of approximately 2 Vpp.

[0026] If the data transmission rate of each channel is 200Gbps, then the total output rate of 16 channels is 3.2Tbps.

[0027] The 16 modulated optical signals enter the wavelength division multiplexing (MUX) unit. This unit combines all the optical signals of different wavelengths into one, and the combined high-intensity optical signal is injected into the optical fiber through the output interface unit for long-distance transmission.

[0028] Throughout the process, the drive and control unit acts as the "brain," providing precise high-speed electrical signals to all Mach-Zehnder modulators and monitoring the status of the entire system to ensure that all components work synchronously and stably.

[0029] As an optional embodiment, the external laser is an integrated eight-wavelength array laser, which is coupled to the optical input end of the Mach-Zehnder modulator via an eight-channel polarization-maintaining fiber; the eight-channel polarization-maintaining fiber is positioned using a high-precision V-groove and fixed using UV-curable adhesive.

[0030] Eight lasers are integrated onto a single chip and connected to a modulator via an eight-channel polarization-maintaining fiber. The array of eight independent lasers integrated onto a single chip ensures high consistency in the initial performance (such as power and linewidth) of the eight optical paths, with coupling loss below 1 dB.

[0031] Mach-Zehnder modulators are extremely sensitive to the polarization state of the input light. Ordinary optical fibers allow the polarization direction of the light to change randomly, resulting in drastic fluctuations in modulation efficiency. The polarization-maintaining fiber used in this invention has internal stress bars that can firmly lock the polarization direction of the light, ensuring constant interference efficiency.

[0032] The eight-channel polarization-maintaining fiber optic cable employs high-precision V-groove positioning, ensuring that each of the eight fibers aligns perfectly with the output ports of the eight lasers. The V-groove provides a positioning reference. After alignment, adhesive is applied and cured within seconds by ultraviolet light, bonding the fibers into the V-grooves. The UV-cured adhesive has an extremely low coefficient of thermal expansion, preventing fiber misalignment due to temperature changes.

[0033] As an optional embodiment, the substrate of each laser channel of the eight-wavelength array laser is provided with a boss structure to achieve thermal isolation; each laser channel integrates a thermoelectric cooler, which, together with a high-precision temperature sensor and PID control circuit, enables independent wavelength tuning.

[0034] Figure 2 This is a schematic diagram of an external laser substrate boss design provided in an embodiment of the present invention.

[0035] If eight lasers are mounted on the same flat plate, heat will be conducted between them, causing wavelength drift. For example... Figure 2 As shown, a boss structure is etched to physically separate each laser, greatly reducing thermal crosstalk.

[0036] A thermoelectric cooler is a semiconductor cooling chip that simultaneously cools and heats when energized. A miniature thermoelectric cooler is attached to the bottom of each laser to precisely control its operating temperature.

[0037] The function of the PID control circuit is as follows: A temperature sensor monitors the laser temperature in real time, and the PID algorithm dynamically adjusts the current of the thermoelectric cooler based on the difference between the target temperature and the actual temperature. Since the laser's output wavelength has a linear relationship with temperature, this closed-loop temperature control can stabilize the wavelength on a standard grid, achieving independent wavelength tuning. Furthermore, it can achieve a tuning accuracy of no less than 0.1 nm, ensuring that the wavelength drift is less than ±0.02 nm within the ambient temperature range of 0℃ to 70℃.

[0038] As an optional embodiment, the Mach-Zehnder modulator is based on silicon-based or thin-film lithium niobate material, manufactured using CMOS-compatible processes, with a modulation bandwidth of not less than 67 GHz and an insertion loss of not more than 3 dB.

[0039] Silicon-based Mach-Zehnder modulators operate based on carrier dispersion. Thin-film lithium niobate (TFLN) Mach-Zehnder modulators utilize the linear electro-optic effect, exhibiting fast response and low loss, making them a preferred material for applications requiring up to 3.2 Tbps.

[0040] By employing CMOS (Complementary Metal-Oxide-Semiconductor) compatible technology, wafer fabrication can be directly achieved using existing mature semiconductor foundries, thereby improving product yield and reducing unit cost.

[0041] The modulation bandwidth is no less than 67GHz, ensuring lossless transmission of a single-channel 106.25GBd (baud rate) PAM4 signal. The insertion loss is no more than 3dB, ensuring low energy loss during long-distance transmission.

[0042] As an optional embodiment, the modulator chip integrates a PCB buried copper process on the back, which is beneficial for heat dissipation. Combined with a local temperature sensor, the operating temperature is stabilized within ±0.1℃ of the set value.

[0043] PCB copper embedding technology refers to embedding a large copper block or copper pillar array within the PCB layer directly beneath the modulator chip. Due to copper's extremely high thermal conductivity, it can quickly conduct away the heat generated by the chip, improving the chip's heat dissipation and effectively suppressing phase drift.

[0044] As an optional embodiment, the optical input port and optical output port of the Mach-Zehnder modulator are respectively provided with directional couplers. 1% to 5% of the optical power is split off through the directional couplers and coupled to a photodetector integrated on the chip. The photodetector is used to monitor the optical power and coupling status in real time, and the monitoring data is uploaded to the control unit through the I2C interface.

[0045] Figure 3 This is a schematic diagram of a modulator input-output coupling monitoring design provided in an embodiment of the present invention.

[0046] like Figure 3 As shown, each optical wavelength modulation unit includes two Mach-Zehnder modulators 21. The Mach-Zehnder modulators 21 are configured via a Y-branch 22 to split the input optical signal of the corresponding wavelength into two independent modulation channels. The optical input port and optical output port of the Mach-Zehnder modulator are respectively provided with directional couplers (not shown in the figure), through which 1% to 5% of the optical power is split and coupled to the photodetector Pd integrated on the chip.

[0047] A directional coupler is a passive device, like a small beam splitter, that takes away only a very small amount of light from the main optical path, that is, splits out 1% to 5% of the optical power, and couples the split optical power to the photodetector.

[0048] The photodetector monitors two core data points: input optical power and output optical power. The I2C interface is a two-wire serial communication bus. The photodetector reports the optical power and coupling status to the control unit (CPU or MCU) via the I2C interface. The control unit analyzes the optical power and coupling status to determine the health status of the link, facilitating remote troubleshooting by maintenance personnel.

[0049] The input optical power is used to determine whether the external laser is aging or whether the optical fiber has detached. The output optical power, combined with the input optical power, can be used to calculate the insertion loss of the current Mach-Zehnder modulator in real time. If the loss increases abnormally, it indicates that there may be cracks or contamination inside the modulator.

[0050] As an optional embodiment, the external laser is a distributed feedback laser array, with each laser output wavelength following the LWDM protocol, the eight wavelengths spaced at 800 GHz, and the wavelength range being the O-band.

[0051] Distributed feedback laser arrays have gratings etched inside. These gratings act like sieves, selecting only a specific wavelength to emit light, ensuring a single longitudinal mode and narrow linewidth, making them ideal light sources for high-speed transmission.

[0052] LWDM (Light Wavelength Division Multiplexing) protocol: It is an industry standard developed by OIF (Optical Interconnection Forum), which specifies the specific wavelength channels in the O-band (1260nm-1360nm).

[0053] The eight wavelengths are spaced at 800 GHz and cover the O-band. The O-band is the zero-dispersion window of optical fiber. When optical signals are transmitted in this band, pulse broadening does not occur, eliminating the need for a dispersion compensation module and making it suitable for high-speed transmission over short distances within the fiber.

[0054] For example, the eight wavelengths are: 1273.54nm, 1277.89nm, 1282.26nm, 1286.66nm, 1295.56nm, 1300.05nm, 1304.58nm, and 1309.14nm.

[0055] As an optional embodiment, the driving circuit corresponding to the PAM4 modulation includes a pre-emphasis equalization module and uses a 7th-order feedforward equalization algorithm for channel loss compensation.

[0056] When PAM4 signals are transmitted in PCB boards and optical fibers, the loss of high-frequency components is much greater than that of low-frequency components, resulting in signal tailing and eye diagram closure. Therefore, channel equalization compensation is required.

[0057] The function of the pre-emphasis equalization module is to artificially increase the amplitude of the high-frequency components in the signal at the transmitting end, so that when it is transmitted to the receiving end, the amplitudes of the high-frequency and low-frequency components are restored to the same value.

[0058] 7th-order feedforward equalization (FFE-7) is a digital filter algorithm. "7th order" means it references the waveform state of seven bits before and after the current moment and calculates a correction value to compensate for the current signal. Higher order results in more precise compensation, but also higher computational consumption. In a 3.2Tbps system, the 7th order was selected as the optimal order after balancing power consumption and performance in this invention.

[0059] As an optional embodiment, the wavelength division multiplexing unit includes three cascaded interferometric wavelength division multiplexer chips, each of which is combined by a multimode interference coupler; the chips are made of low-loss silicon nitride material and have an insertion loss of less than 1.5dB.

[0060] Figure 4 This is a schematic diagram of a cascaded architecture design provided for an embodiment of the present invention.

[0061] like Figure 4 As shown, the three-stage cascaded interferometric wavelength division multiplexer chip uses a three-stage cascade method to combine eight wavelengths into one channel.

[0062] In each stage, the multimode interference coupler (MMI) acts as an optical splitter / combiner. Compared to traditional Y-branching, MMI is insensitive to process errors and can maintain beam splitting uniformity over a wide wavelength range.

[0063] The chip is made of low-loss silicon nitride material, with losses as low as 0.1dB / cm. The total loss is less than 1.5dB, allowing more than 70% of the optical power to be retained, ensuring a sufficiently strong optical signal at the final output port.

[0064] The wavelength division multiplexing (WDM) unit is fabricated using silicon-based silicon nitride technology, and its fabrication steps are as follows: S1: Deposit a 2-3 μm thick SiO2 lower cladding layer on a silicon substrate; S2: A 0.8 μm thick SiN core layer was deposited using PECVD; S3: Waveguide patterns are formed by electron beam lithography and reactive ion etching; S4: Deposit a 0.5-3 μm SiO2 cladding layer and anneal it to reduce losses.

[0065] As an optional embodiment, the output of the wavelength division multiplexer chip is coupled to an output optical fiber, and the two output optical fibers are connected to an MPO connector, with each output optical fiber transmitting a high-speed optical signal of 8 wavelengths.

[0066] After complex internal modulation and multiplexing, the output of the wavelength division multiplexing unit is coupled to two output optical fibers, allowing each fiber to simultaneously transmit high-speed optical signals of eight wavelengths at a rate of 1.6 Tbps. These two fibers are then converged and connected to an MPO-12 connector. In this way, the entire system achieves a total single-port transmission rate of 3.2 Tbps through this MPO interface, using parallel output from two optical fibers.

[0067] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: Significantly improved thermal management and stability: By externalizing the laser and equipping it with an independent and precise thermoelectric cooler and thermal isolation structure, the influence of laser heat generation on the optical chip is effectively isolated, achieving high-precision (≤0.1nm) independent tuning and stable control of each wavelength, which greatly improves the overall temperature stability and long-term operational reliability of the system.

[0068] Simplified structure and reduced cost: The external laser is directly coupled through a fiber array, eliminating the need for a large number of discrete optical components such as lenses and isolators and their complex alignment processes in traditional built-in solutions. This greatly simplifies the optical path structure and packaging process, and reduces the packaging size and manufacturing cost.

[0069] High-performance, high-density integration: Employing a high-performance CMOS-compatible modulator (high bandwidth, low insertion loss) and a high-efficiency cascaded wavelength division multiplexer, it achieves high-density integration and signal processing of 16 200Gbps channels at the chip level, effectively supporting an ultra-high transmission capacity of 3.2Tbps.

[0070] Enhanced maintainability and reliability: The external laser design makes it a relatively independent and replaceable unit. In the event of a failure, it may not be necessary to replace the entire optical engine, which significantly reduces maintenance costs and complexity and improves the serviceability and reliability of the system.

[0071] Clear architectural scalability: The external laser combined with multi-channel optical modulation / multiplexing architecture proposed in this invention provides a clear and feasible technical path for future evolution to more wavelengths and higher speeds, and has good technical foresight.

[0072] In summary, the optical emission engine based on an eight-wavelength multiplexing architecture provided in this embodiment of the invention includes: an external laser for providing eight different wavelength light sources; eight optical wavelength modulation units, each comprising two Mach-Zehnder modulators configured via a Y-branch to divide the input optical signal of the corresponding wavelength into two independent modulation channels; wherein each modulation channel is assigned a different wavelength, and each modulation channel supports PAM4 modulation format data transmission; a wavelength division multiplexing unit including multiple wavelength division multiplexers for multiplexing the optical signals of all modulation channels; an output interface unit for outputting the multiplexed optical signal to an optical fiber; and a drive and control unit for providing electrical drive signals and system control. In this solution, the external laser is directly coupled through an optical fiber array, successfully solving the key bottleneck of the built-in solution. Combined with the eight-wavelength multiplexing scheme, it provides a high-performance, highly stable, easy-to-maintain, and future-oriented single-port 3.2Tbps optical emission engine.

[0073] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0075] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An optical emission engine based on an eight-wavelength multiplexing architecture, characterized in that, include: An external laser is used to provide light sources of eight different wavelengths; There are 8 optical wavelength modulation units. Each optical wavelength modulation unit includes two Mach-Zehnder modulators. The Mach-Zehnder modulators are configured via Y-branch to divide the input optical signal of the corresponding wavelength into two independent modulation channels. Each modulation channel is assigned a different wavelength, and each modulation channel supports data transmission in PAM4 modulation format. A wavelength division multiplexing unit, comprising multiple wavelength division multiplexers, is used to multiplex the optical signals of all modulation channels; The output interface unit is used to output the combined optical signal to the optical fiber; Drive and control unit, used to provide electric drive signals and system control.

2. The light-emitting engine according to claim 1, characterized in that, The external laser is an integrated eight-wavelength array laser. The external laser is coupled to the optical input end of the Mach-Zehnder modulator through an eight-channel polarization-maintaining fiber. The eight-channel polarization-maintaining fiber is positioned using a high-precision V-groove and fixed with UV-curable adhesive.

3. The light-emitting engine according to claim 1, characterized in that, The substrate of each laser channel of the eight-wavelength array laser has a boss structure to achieve thermal isolation; each laser channel integrates a thermoelectric cooler, which, together with a high-precision temperature sensor and PID control circuit, enables independent wavelength tuning.

4. The light-emitting engine according to claim 1, characterized in that, The Mach-Zehnder modulator is based on silicon-based or thin-film lithium niobate material, manufactured using CMOS-compatible technology, with a modulation bandwidth of not less than 67 GHz and an insertion loss of not more than 3 dB.

5. The light-emitting engine according to claim 1, characterized in that, The modulator chip integrates a PCB buried copper process on the back, which is beneficial for heat dissipation. Together with a local temperature sensor, it stabilizes the operating temperature within the set range of ±0.1℃.

6. The light-emitting engine according to claim 1, characterized in that, The Mach-Zehnder modulator has directional couplers at its optical input and output ports. 1% to 5% of the optical power is split off by the directional couplers and coupled to a photodetector integrated on the chip. The photodetector is used to monitor the optical power and coupling status in real time, and the monitoring data is uploaded to the control unit via an I2C interface.

7. The light-emitting engine according to claim 1, characterized in that, The external laser is a distributed feedback laser array, with each laser outputting a wavelength that follows the LWDM protocol. The eight wavelengths are spaced 800 GHz apart, and the wavelength range is the O-band.

8. The light-emitting engine according to claim 1, characterized in that, The driving circuit corresponding to the PAM4 modulation includes a pre-emphasis equalization module and uses a 7th-order feedforward equalization algorithm for channel loss compensation.

9. The light-emitting engine according to claim 1, characterized in that, The wavelength division multiplexing unit includes three cascaded interferometric wavelength division multiplexer chips, each of which is combined by a multimode interference coupler; the chips are made of low-loss silicon nitride material and have an insertion loss of less than 1.5dB.

10. The light-emitting engine according to claim 1, characterized in that, The output terminals of the wavelength division multiplexer chip are respectively coupled to an output optical fiber, and the two output optical fibers are connected to an MPO connector. Each output optical fiber transmits high-speed optical signals of 8 wavelengths.

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