Pluggable external optical module and optical communication equipment

Abstract

The invention relates to the technical field of optical communication, and provides a pluggable external optical module which comprises multiple paths of lasers, each laser is divided into two laser array groups, the two laser array groups are arranged in a staggered mode, and the two laser array groups are arranged on a circuit board through a heat dissipation structure. The invention further provides optical communication equipment which comprises a switch and the pluggable external optical module, and the pluggable external optical module is installed on the switch in a pluggable mode. According to the invention, through the staggered lasers, the heat path area is increased, heat dissipation is facilitated, and the difficulty of polarization FA assembly is effectively reduced, so that the yield of module production and the stability of light output of each channel are improved. In addition, through discrete arrangement, heat distribution among the channels is effectively isolated, and the signal transmission performance is further optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of optical communications, and in particular to a pluggable external optical module and optical communication equipment. Background Art

[0002] With the growing use of high-bandwidth applications such as artificial intelligence / machine learning, data center users are increasingly demanding effective design solutions for optical communication equipment with low power consumption, high speed and high switching capacity. CPO (Co-Packaged Optical) uses compact interconnect packaging design for a variety of miniaturized and integrated optoelectronic components to bring optical devices and dedicated integrated circuit chips closer together, shorten transmission distances, reduce power consumption, reduce signal attenuation and electromagnetic interference, and thus achieve direct drive or low-power drive of high-speed signals between interfaces. However, due to the compact integration of optoelectronic modules and chips, current CPO switches require effective heat dissipation management technology to handle the heat load brought by high-density integration. The external light source module separates the thermal environment of the laser from the co-packaged module components, reduces the complexity of optoelectronic integrated packaging design and manufacturing, provides a more effective cooling solution, and saves the internal space occupied by CPO. ELSFP (External Laser Small Form-Factor Pluggable) uses an external laser to provide optical power for optical engines integrated in switches, artificial intelligence and machine learning ASICs (application specific integrated circuits), etc. Its main function is to provide a safe coupled light source module. The pluggable external light source module allows the use of high-power, high-performance LD (Laser Diode) chips for power supply, can provide light sources for multiple modules, and can achieve higher maintainability replacement solutions in the event of laser failure on site. However, the integrated packaging of small-size optical modules faces limited space, and the layout of multi-channel high-power lasers will also bring problems such as high power consumption and effective heat dissipation. Summary of the invention

[0003] The object of the present invention is to provide a pluggable external optical module and an optical communication device, which can at least solve some of the defects in the prior art.

[0004] To achieve the above-mentioned purpose, an embodiment of the present invention provides the following technical solution: a pluggable external optical module, comprising multiple lasers, each of the lasers is divided into two groups of laser array groups, the two groups of laser array groups are staggered, and the two groups of laser array groups are both arranged on a heat dissipation structure.

[0005] Furthermore, the heat dissipation structure includes a thermally conductive ceramic gasket for the laser to rest on, and the thermally conductive ceramic gasket is arranged on a tungsten copper heat dissipation substrate.

[0006] Furthermore, it also includes an optical port and an electrical port, and the optical port and the electrical port are arranged on the same side.

[0007] Furthermore, it also includes a light collecting coupling lens group for improving coupling efficiency, and the laser light emitted by the laser is coupled through the light collecting coupling lens group.

[0008] Furthermore, the light collecting coupling lens group includes a collimating lens, a polarization isolator and a collecting lens arranged in sequence along the light path direction, the collimating lens is used to convert the light beam into a parallel light beam, the polarization isolator is used to control the polarization state, and the collecting lens is used to gather the light beam and then output it.

[0009] Furthermore, the polarization isolator includes a Faraday rotator and a polarizer, and the Faraday rotator and the polarizer cooperate to perform polarization compensation.

[0010] Furthermore, it also includes an MT jumper plug for inputting the coupled light beam, and the MT jumper plug has a plurality of polarization-maintaining optical fibers.

[0011] Furthermore, the MT jumper plug also has an alignment component.

[0012] Furthermore, it also includes a detection unit for real-time detection of the laser light output power.

[0013] An embodiment of the present invention provides another technical solution: an optical communication device, including a switch, and also including the above-mentioned pluggable external optical module, wherein the pluggable external optical module is pluggably installed on the switch.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. By staggering the lasers, not only the heat path area is increased, which is convenient for heat dissipation, but also the difficulty of polarization FA (Fiber-Array) assembly is effectively reduced, thereby improving the yield of module production and the stability of light output of each channel. In addition, through discrete arrangement, the heat distribution between channels is effectively isolated, further optimizing the signal transmission performance.

[0016] 2. The light collection coupling lens group is equipped with an independent lens group and isolator to ensure high polarization consistency and high coupling efficiency of the light source signal. The light signal is stably transmitted to the end face of the polarization-maintaining fiber through a high-precision lens group, ensuring that the polarization direction of the light signal does not rotate during the transmission process, thereby improving the polarization stability and transmission quality of the system.

[0017] 3. The MT patch cord plug used can effectively reduce the offset error between optical fibers through alignment, improve the docking quality, and use polarization-maintaining optical fiber transmission to reduce polarization mode dispersion and improve transmission efficiency and system stability.

[0018] 4. The detection unit can detect the output power of the laser in real time for easy regulation.

[0019] 5. The optical communication equipment is installed on the switch in the form of an external light source, which has a convenient replacement function. When the pluggable light source module fails due to a fault or performance degradation, it can be easily removed and replaced without changing the hardware structure of the switch body. By adopting this design, users can flexibly insert different types or quantities of pluggable light source modules on the switch according to the actual needs of the switch to achieve flexible configuration of the light source module. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a pluggable external optical module provided by an embodiment of the present invention;

[0021] Figure 2 An exploded schematic diagram of a pluggable external optical module provided by an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the coordination of a laser, a thermally conductive ceramic gasket, a detection unit, and a tungsten-copper heat dissipation substrate of a pluggable external optical module provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of various components on a circuit board of a pluggable external optical module provided in an embodiment of the present invention;

[0024] Figure 5 A schematic diagram of a detection unit, a laser, a light collection and coupling lens group, and a polarization optical fiber assembly of a pluggable external optical module provided in an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of a pluggable MT jumper plug for an external optical module provided by an embodiment of the present invention;

[0026] Figure 7 A schematic diagram of a polarized optical fiber of a pluggable external optical module provided by an embodiment of the present invention;

[0027] Figure 8 A schematic diagram of photoelectric feedback control of a pluggable external optical module provided by an embodiment of the present invention;

[0028] In the accompanying drawings: 11-upper cover; 12-circuit board; 13-base; 121-tungsten copper heat dissipation substrate; 122-thermal conductive ceramic gasket; 123-detection unit; 124-laser; 125-light collecting coupling lens group; 1251-collimating lens; 1252-polarization isolator; 1253-collecting lens; 1254-polarization-maintaining fiber end face; 126-polarization fiber assembly; 127-MT jumper plug; 1271-alignment hole; 1272-polarization-maintaining fiber; 12721-stress area; 12722-fiber core; 2-optical port; 3-electrical port. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figures 1 to 4, an embodiment of the present invention provides a pluggable external optical module, including a multi-channel laser 124, each of the lasers 124 is divided into two groups of laser 124 array groups, the two groups of laser 124 array groups are staggered, and the two groups of laser 124 array groups are arranged on the circuit board 12 through the heat dissipation structure. The circuit board 12 is arranged between the upper cover 11 and the base 13. Preferably, the heat dissipation structure includes a thermally conductive ceramic gasket 122 for the laser 124 to rest on, and the thermally conductive ceramic gasket 122 is arranged on a tungsten copper heat dissipation substrate 121. In this embodiment, a discrete staggered design is adopted for the arrangement of LD. This design method not only increases the thermal path area and facilitates heat dissipation, but also effectively reduces the difficulty of polarization FA assembly and production, thereby improving the yield of module production and the stability of the light output of each channel. In addition, through the discrete arrangement, the heat distribution between the channels is effectively isolated, and the signal transmission performance is further optimized. The heat dissipation structure dissipates heat by first using AIN high thermal conductivity ceramic gaskets to place the laser 124. Preferably, each laser 124 can be configured with a thermal conductive ceramic gasket 122, so that the laser 124 in each light output channel can effectively dissipate heat, and then the heat is dissipated through the tungsten copper heat dissipation substrate 121. Specifically, the external light source module in the present invention can provide an eight-channel light source. The light source assembly includes eight DFB (Distributed Feedback Laser) lasers 124, and MPD (Monitor Photo-diode) and temperature-sensitive devices are respectively provided for the LD light output and heat dissipation areas to monitor the light output power and operating temperature of the laser 124 to ensure the stability of the light source assembly. The light output by the light source assembly of the present invention is a CW (Continuous Wave) laser with a single wavelength of 1310nm. See Figure 3, different from the traditional single linear eight-channel array LD arrangement type, the present invention uses an interlaced 2*four-channel high-power laser 124 array, and the light source generated by the laser 124 is shaped and coupled into the polarization-maintaining FA end face by a high-coupling-efficiency optical lens group. The laser source signal is managed by the polarization isolator 1252 and then input into the CPO switch. Each optical channel is separated from each other as a single optical power supply channel, and the coupling and transmission of each light output interface and the light source component belong to free space propagation. The interlaced structural design will increase the heat dissipation area of ​​the LD chip, and the heat diffusion distance will be effectively improved, thereby reducing the local temperature of the LD chip after long-term operation. By comparing the simulation results, under the same coupling efficiency and output optical power conditions, the operating temperature of the interlaced LD chip is reduced by an average of 1.0 degrees Celsius, and the module housing temperature is reduced by 0.35 degrees Celsius. Thanks to the excellent heat dissipation management and high coupling efficiency lens group, the power consumption of a single LD is 0.23W, and the overall power consumption of the module is about 2.0W. Its power consumption level is much lower than the market average. The optical signals transmitted in ELSFP are all transmitted using polarization-maintaining fiber 1272 as the transmission medium. The staggered LD arrangement reduces the original eight-channel package FA requirement to 2*four-channel discrete FAs, such as Figure 4 As shown. During engineering manufacturing, considering the panda eye polarization angle of the polarization-maintaining fiber 1272 in a single optical fiber channel and the control of the interval between each channel, the assembly of the four-channel polarization-maintaining fiber 1272 will greatly reduce the processing difficulty and production cost compared to the eight-channel polarization-maintaining fiber 1272, and further improve the product yield and optical packaging accuracy. This is of great significance for mass production.

[0031] See also Figure 1 and Figure 2 , the optical module also includes an optical port 2 and an electrical port 3, and the optical port 2 and the electrical port 3 are arranged on the same side. In this embodiment, the optical port 2 and the electrical port 3 are arranged on one side of the module, which can achieve safe and reliable optical signal transmission. The optical port 2 of this layout is designed as a card sleeve configuration, specifically located on the left side of the ELSFP (External Laser Small Form Factor Pluggable) module and the host connector. Through this design layout, the connection path and side space layout of the optoelectronic signal are simplified, the loss and interference in the signal transmission process are reduced, and the overall performance of the optical communication equipment is further improved.

[0032] See also Figures 3 to 5, the optical module also includes a light collection coupling lens group 125 for improving coupling efficiency and reducing power consumption, and the laser emitted by the laser 124 is coupled through the light collection coupling lens group 125. In this embodiment, the light collection coupling lens group 125 can improve the coupling efficiency, and benefit from the high coupling efficiency lens collection system, thereby greatly reducing the overall power consumption of the module. Specifically, the light collection coupling lens group 125 includes a collimating lens 1251, a polarization isolator 1252 and a collecting lens 1253 arranged in sequence along the optical path direction, the collimating lens 1251 is used to convert the light beam into a parallel light beam, the polarization isolator 1252 is used to control the polarization state, and the collecting lens 1253 is used to gather the light beam and then output it. In the optical signal coupling part, each optical channel is equipped with an independent lens group and isolator to ensure high polarization consistency and high coupling efficiency of the light source signal. The optical signal is stably transmitted to the polarization-maintaining optical fiber end face 1254 through a high-precision lens group, ensuring that the polarization direction of the optical signal does not rotate during the transmission process, thereby improving the polarization stability and transmission quality of the system. Among them, the point light source laser emitted by the laser 124 is converted into a parallel light beam after passing through the collimating lens 1251, and the polarization state is controlled by the polarization isolator 1252, and is efficiently coupled to the end face 1254 of the polarization-maintaining optical fiber 1272 after passing through the collecting lens 1253. After the LD output point light source is collimated, it is passed through the polarization isolator 1252 to maintain the TE mode polarization, and the electric field vibration direction is parallel to the chip surface, and its output is highly consistent with the input direction. The collecting lens 1253 is used for back-end light collection and coupling. The optical module involves eight-channel power supply, and a collimating lens 1251, a polarization isolator 1252, and a collecting lens 1253 are provided between each laser 124 and the receiving end of the polarization-maintaining optical fiber 1272. The optical signal emitted by each independent DFB laser 124 passes through the collimating lens 1251, the polarization isolator 1252, and the collecting lens 1253 in turn to enter the optical input end of the polarization-maintaining optical fiber 1272. Figure 5As shown, the collimating lens 1251 is used to diverge the light source signal to ensure that the light beam propagates in a parallel state. The isolator is used to reduce the reverse transmission of the light signal, protect the light source device, reduce the bit error rate and prevent feedback. The collecting lens 1253 is used to collect the parallel light beam signal, and the spot shape and size match the optical fiber core mode field diameter to achieve high-efficiency coupling. When the arrangement sequence of the light collection coupling lens group 125 is selected to be located in the middle of the lens group, this design will provide a higher coupling tolerance and reduce the assembly accuracy requirements. If the isolator is placed after the collecting lens 1253, the overall optical path length will be controlled and compressed. The specific implementation of the scheme can comprehensively consider the internal component row space and external dimensions of the device and flexibly regulate. In a specific embodiment, the parallel light beam is efficiently coupled to the polarization-maintaining optical fiber 1272 with a mode field diameter of 9.2μm through the collecting lens 1253. After simulation calculation, the coupling efficiency can be optimized to 88%, and the power consumption demand of the module is further compressed. Referring to the OIF protocol, the output power requirement for ELSFP optical port 2 is 18.5dBm, and the LD input power should be no less than 80.7mW. It should be noted that when the stable optical output power of the LD chip used in the present invention is 200mW, 176mW, i.e. 22.46dBm output (meeting the one-to-eight multi-channel application) can be obtained at the maximum coupling efficiency. The output power of optical port 2 provides more expansion space for the subsequent multi-channel and large-capacity work of CPO switches.

[0033] See also Figure 6 and Figure 7, the polarization isolator 1252 includes a Faraday rotator and a polarizer, and the Faraday rotator and the polarizer cooperate to perform polarization compensation. As an optical engine or CPO module supported by ELSFP, wavelength and polarization requirements are given to the basic characteristics of the optical fiber output optical signal. In this embodiment, a four-piece polarization isolator 1252 design is selected to ensure that the polarization directions of the input and output ends are consistent by combining four specific Faraday rotators and polarizers. It mainly utilizes the non-reciprocity of the Faraday effect, that is, when the light wave passes through the Faraday rotator in the magnetic field, a fixed direction of polarization rotation will occur. The four-piece Faraday isolator usually uses a combination of a Faraday rotator and a λ / 2 wave plate to perform polarization compensation. In the forward propagation, the polarization direction of the light is restored to be consistent, while in the reverse propagation, the polarization direction is disrupted, so as to achieve the maintenance and isolation of the polarization direction of the optical signal in the forward and reverse transmission. In order to meet the same polarization state of the output optical port 2, each channel uses polarization-maintaining fiber 1272 for transmission from the output port of the MT jumper plug 127 after being coupled into the FA, thereby reducing polarization mode dispersion and improving transmission efficiency and system stability. The polarization-maintaining fiber 1272 has a stress area 12721 and a core 12722. The polarization-maintaining fiber 1272 introduces a birefringence effect to enable the polarization state of light to remain unchanged during transmission. The light propagation speeds of the two mutually perpendicular polarization directions (fast axis and slow axis) in the core 12722 are different, resulting in the polarization state of the light remaining unchanged during transmission, and the polarization direction will not change due to external factors (such as temperature changes, stress, etc.). Figure 6 As shown, 8 channels in the MT-12 channel are filled with polarization-maintaining fiber 1272, and the remaining unused channels are filled with dummy fibers to prevent contamination or possible damage caused by incorrect pairing.

[0034] See also Figure 6 and Figure 7, the optical module also includes an MT jumper plug 127 for inputting the coupled light beam, and the MT jumper plug 127 has a plurality of polarization-maintaining optical fibers 1272. The MT jumper plug 127 also has an alignment component. The polarization-maintaining optical fiber 1272 has a stress area 12721 and a fiber core 12722. In this embodiment, the optical connection part uses a 12-core MT jumper plug 127 that complies with TIA-604-5, IEC 61754-7-1 and IEC 61755-3-31 standards. The coupled light beam is input to the MT jumper plug 127 through the polarization optical fiber assembly 126. In multi-core connection, the alignment hole 1271 of the MT jumper plug 127 and the corresponding guide pins ensure the precise alignment of the optical fibers, thereby effectively reducing the offset error between the optical fibers and improving the docking quality. In addition, in order to further improve the docking accuracy of multi-core fiber connectors, alignment components are configured in the MT-12 core sleeve to achieve efficient and stable multi-channel fiber coupling of 8 PMF (Polarization Maintaining Optical Fiber, polarization-maintaining fiber 1272) channels. These alignment components independently and accurately position each channel, effectively reducing insertion loss and ensuring the stability and reliability of optical signal transmission between different channels. Specifically, after a laser light source with a certain polarization state is transmitted through the polarization-maintaining fiber 1272, the alignment hole 1271 is used to position the output end MT jumper plug 127, and the output light of each independent polarization-maintaining fiber 1272 is coupled into the back-end device, where the structure of the polarization-maintaining fiber 1272 is a panda eye, consisting of a stress area 12721 and a fiber core 12722.

[0035] See also Figures 3 to 8 , the optical module also includes a detection unit 123 for real-time detection of the laser output power. In this embodiment, the electrical signal is coordinated by the temperature sensitivity and MPD on the circuit board 12, and each LD light output channel is configured with an independent MPD detection unit 123 for real-time monitoring of the light output power and APC (Auto-power Control) function. When the environment changes, the APC adjusts the LD Bias current according to the real-time monitored light output power to achieve optical power stability. The light source component inside the module relies on the MPD feedback mechanism to ensure stable output power, thereby realizing dynamic regulation of the LD's operating current, effectively controlling the output power and operating temperature of the light source component, and ensuring its stability in various working environments. Figure 8 The figure shows the direction of the photoelectric feedback control signal, where IDAC (Interim Digital-Analog Converter) is a current-type digital-to-analog converter and CW laser is a continuous laser, which is controlled by MCU in combination with various devices.

[0036] So far, the optical module of the above embodiment can meet the module output optical power, polarization management requirements and reasonably reduce the module power consumption, solve the current problem and meet the protocol indicators. The pluggable external light source module with a high coupling, low loss and effective heat dissipation LD arrangement scheme will provide effective technical support for the layout of 1.6T CPO and even higher capacity switches.

[0037] See also Figures 1 to 8 , an embodiment of the present invention provides an optical communication device, including a switch and the above-mentioned pluggable external optical module, wherein the pluggable external optical module is pluggable and installed on the switch. In this embodiment, the pluggable light source module can be installed on the switch in the form of an external light source, so as to have a convenient replacement function. When the pluggable light source module fails due to a fault or performance degradation, it can be conveniently disassembled and replaced without changing the hardware structure of the switch body. By adopting this design, the user can flexibly insert different types or quantities of pluggable light source modules on the switch according to the actual needs of the switch to achieve flexible configuration of the light source module. In a specific implementation, the pluggable light source module can be docked with the switch through a standard interface to achieve efficient and stable optical signal transmission, which is particularly suitable for optical signal transmission of a CPO switch. This configuration significantly reduces the number of connecting optical fibers required for traditional optical signal transmission, saves internal connection resources of the switch, and reduces the occupation of the front panel space of the CPO switch. At the same time, the switch described in the present invention is not limited to a CPO switch, but can also be a switch of other structures, such as an ordinary high-performance network switch, a data center switch, and other devices that require an external pluggable light source module.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pluggable external optical module, characterized in that: It comprises multiple lasers, each of which is divided into two laser array groups, the two laser array groups are staggered, and the two laser array groups are both arranged on the heat dissipation structure.

2. The pluggable external optical module according to claim 1, characterized in that: The heat dissipation structure comprises a thermally conductive ceramic pad for the laser to rest on, and the thermally conductive ceramic pad is arranged on a tungsten copper heat dissipation substrate.

3. The pluggable external optical module according to claim 1, wherein: It also includes an optical port and an electrical port, and the optical port and the electrical port are arranged on the same side.

4. The pluggable external optical module according to claim 1, wherein: It also includes a light collecting coupling lens group for improving coupling efficiency, and the laser light emitted by the laser is coupled through the light collecting coupling lens group.

5. The pluggable external optical module according to claim 4, characterized in that: The light collecting coupling lens group includes a collimating lens, a polarization isolator and a collecting lens arranged in sequence along the light path direction. The collimating lens is used to convert the light beam into a parallel light beam, the polarization isolator is used to control the polarization state, and the collecting lens is used to gather the light beam and then output it.

6. The pluggable external optical module according to claim 5, characterized in that: The polarization isolator comprises a Faraday rotator and a polarizer, and the Faraday rotator and the polarizer cooperate to perform polarization compensation.

7. The pluggable external optical module according to claim 1, characterized in that: The invention also comprises an MT patch cord plug for inputting the coupled optical beam, wherein the MT patch cord plug has a plurality of polarization-maintaining optical fibers.

8. The pluggable external optical module according to claim 7, characterized in that: The MT jumper plug also has an alignment component.

9. The pluggable external optical module according to claim 1, characterized in that: It also includes a detection unit for real-time detection of the laser light output power.

10. An optical communication device, comprising a switch, characterized in that: It also includes a pluggable external optical module as described in any one of claims 1 to 9, and the pluggable external optical module is pluggably installed on the switch.

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