CN212463216U

CN212463216U - Optical module with single-channel transmission rate of 100Gbps

Info

Publication number: CN212463216U
Application number: CN202020850652.5U
Authority: CN
Inventors: 田波; 胡长飞; 李梓文; 许其建; 杨颖�
Original assignee: Wuhan Huagong Genuine Optics Tech Co Ltd
Current assignee: Wuhan Huagong Genuine Optics Tech Co Ltd
Priority date: 2020-05-20
Filing date: 2020-05-20
Publication date: 2021-02-02
Anticipated expiration: 2030-05-20

Abstract

The utility model discloses an optical module that single channel transmission rate is 100Gbps, which comprises a housin, PCB board and optical connector, be equipped with power module on the PCB board, microcontroller, the DSP treater, EML driver and detector, power module is used for supplying power for whole optical module, microcontroller respectively with the DSP treater, EML driver electricity is connected, the output of detector is connected with the input electricity of receiving side DSP treater, the output of receiving side DSP treater is connected with the golden finger electricity, the output of transmitting side DSP treater is connected with the input electricity of EML driver, the output of EML driver is connected with the EML laser electricity; the PCB board is locally buried underground with the radiating block, makes the direct dress of pasting of heating element on the radiating block, and the heat conductivity of radiating block is higher than the heat conductivity of PCB panel, and shells inner wall is equipped with the heat dissipation boss, and PCB board and heat dissipation boss contact use the heat conduction material to fill between heat dissipation boss and the PCB board. The optical module reduces the product cost.

Description

Optical module with single-channel transmission rate of 100Gbps

Technical Field

The utility model relates to an optical fiber communication technical field, in particular to single channel transmission rate is 100 Gbps's optical module.

Background

At present, global information technology innovation enters a new round of acceleration period, and 5G, loT, AI, VR/AR and other new generation information technologies and applications rapidly evolve, and important influences are generated on the aspects of scale, construction mode and performance of a data center. 5G and loT will drive explosive growth of data volume, lead to a strong increase in demand of data centers, drive the overall construction scale of data centers to continuously increase at a high speed, and further increase the proportion of large data centers which are intensively constructed.

To achieve high-speed interconnection of switches or routers between buildings and to be compatible with existing QSF28 package interfaces, increasing the transmission rate of a single channel becomes especially important. Compared with the current 100G QSFP28 optical module (four-way 25 Gbps), the 100G FR1 optical module only uses one optical device, so that the cost of the optical module can be greatly saved, and the 100G FR1 optical module packaged based on QSFP28 can be completely compatible with the existing 100G switch interface.

In the current market background, the product generally adopts the following key technologies, and the technical analysis is as follows:

1. the silicon photo scheme has high process cost.

2. The EML device with the refrigeration function has the advantages of airtight packaging and high packaging cost; meanwhile, due to the adoption of a device packaging technology, the distance between the photoelectric chips is increased, and the difficulty of circuit design is increased.

3. The scheme of the DML device with the refrigeration function is that no DML device meeting the requirements exists temporarily.

Disclosure of Invention

An object of the utility model is to overcome prior art's defect, provide a single channel transmission rate is 100 Gbps's optical module, aim at using more mature, low-cost scheme, realize product design.

The utility model aims at adopting the following scheme to realize: the utility model discloses an optical module with single channel transmission rate of 100Gbps, which comprises a shell, a PCB and an optical connector, wherein the PCB is arranged in the shell, the end part of the PCB is provided with a golden finger which is an electrical interface for the communication between the optical module and a single board of a switch, the optical connector is arranged at the end part of the shell and is used for being butted with an external optical fiber, the optical connector and the golden finger are respectively arranged at the two ends of the shell, the PCB is provided with a power module, a microcontroller, a DSP processor, an EML driver and a detector, the power module is used for supplying power to the whole optical module, the microcontroller is respectively electrically connected with the DSP processor and the EML driver, the detector is used for receiving optical signals with modulation sent by the optical fiber butted with the first optical connector and converting the received optical signals with modulation into electrical signals, the output end of the detector is electrically connected with the input end of the DSP processor at the, the output end of the receiving side DSP processor is electrically connected with the golden finger, the output end of the transmitting side DSP processor is electrically connected with the input end of the EML driver, the output end of the EML driver is electrically connected with the EML laser, and the EML driver is used for controlling the EML laser to output an optical signal with modulation and transmitting the optical signal to an optical fiber butted with the second optical connector; the microcontroller is electrically connected with the golden finger; the PCB board part has buried the radiating block underground, makes the direct dress of pasting of heating element on the radiating block, and the heat conductivity of radiating block is higher than the heat conductivity of PCB panel, and the heat conducts away through the radiating block, shells inner wall is equipped with the heat dissipation boss, PCB board and heat dissipation boss contact use the heat conduction material to fill between heat dissipation boss and the PCB board.

The purpose of the communication connection between the microcontroller and the golden finger through the low-speed signal interface and the I2C is that the host side communicates with the module, reports the state of the module and the host issues an instruction.

The heating element has a heating value related to power consumption, and mainly includes a DSP chip, an EML driver, a laser, and a detector, and if the heat does not have a heat dissipation path, the performance of the module may deteriorate even more, which may cause the module to malfunction.

The heat dissipation boss and the shell are integrated.

Further, the heat dissipation block is a copper block.

Furthermore, the heat conduction material filled between the heat dissipation boss and the PCB is silicone grease heat conduction gel.

Further, the detector comprises a PD chip and a TIA chip, the TIA chip is electrically connected with the microcontroller, the PD chip and the TIA chip are adhered to the PCB through conductive silver adhesive, the output end of the PD chip is connected with the input end of the TIA chip through a gold wire bonding technology, and the output end of the TIA chip is electrically connected with the input end of the receiving side of the DSP processor.

Further, the optical connector is an LC adapter.

Further, the DSP processor is a transceiver and is embedded with an EML driver.

Further, the microcontroller is packaged by WLCSP.

Further, the EML laser was loaded on a SiN substrate and electrically connected to an EML driver using gold wire bonding technology.

Further, the EML laser does not include a TEC; the EML laser is internally provided with a photoelectric monitoring diode which is used for monitoring the optical power of the EML laser, changing the bias current of the laser according to P-I curves, namely optical power-bias current curves under different temperature conditions and stabilizing the output optical power.

The utility model has the advantages that: the utility model discloses an optical module has adopted and has loaded the EML laser instrument on the SiN base plate and has used gold thread bonding technique to carry out electrical connection with EML laser instrument and EML driver, PCB board part has buried the radiating block underground, makes heating element directly paste the dress on the radiating block, and the thermal conductivity of radiating block is higher than the thermal conductivity of PCB panel, and the heat conducts away through the radiating block, the shells inner wall is equipped with the heat dissipation boss, PCB board and heat dissipation boss contact use the heat conduction material to fill between heat dissipation boss and the PCB board, make the utility model discloses an EML laser instrument can adopt uncooled EML COC scheme, but on the one hand reducible temperature control circuit reduces the product consumption; on the other hand, the TEC packaging process can be omitted, and for chip packaging, a non-airtight packaging process can be adopted in combination with COC capability.

And the EML laser is internally provided with a photoelectric monitoring diode which is used for monitoring the optical power of the EML laser, changing the bias current of the laser according to a P-I curve, namely an optical power-bias current curve, under different temperature conditions and stabilizing the output optical power.

Drawings

Fig. 1 is a schematic block diagram of an optical module with a single channel transmission rate of 100Gbps according to the present invention;

fig. 2 is a schematic front view of a PCB board of the optical module with a single channel transmission rate of 100Gbps according to the present invention;

fig. 3 is a schematic reverse side view of the PCB board of the optical module with a single channel transmission rate of 100Gbps according to the present invention;

fig. 4 is a schematic side view of the PCB board of the optical module with a single channel transmission rate of 100Gbps according to the present invention.

In the attached drawing, 1 is a PCB, 2 is an EML laser, 3 is a DSP processor, 4 is a detector, and 5 is an MCU.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1 to 4, the present embodiment provides an optical module with a single channel transmission rate of 100Gbps, including a housing, an unlocking device, a PCB and an optical connector, where the PCB is disposed in the housing. The shell of the optical module comprises a bottom shell and an upper cover, and the bottom shell is fixedly connected with the upper cover through bolts. The unlocking device and the bottom shell PCB plate are positioned between the bottom shell and the upper cover. The end of the PCB board is provided with a golden finger which is an electrical interface for the communication between the optical module and the single board of the switch, the optical connector is arranged at the end of the bottom shell, used for being butted with an external optical fiber, the optical connector and the golden finger are respectively positioned at the two ends of the shell, the PCB is provided with a power supply module, a microcontroller MCU, a DSP processor, an EML driver and a detector, the power supply module is used for supplying power to the whole optical module, the microcontroller MCU is respectively and electrically connected with the DSP processor and the EML driver, the detector is for receiving a modulated optical signal transmitted by an optical fiber that interfaces with the first optical connector, the received optical signal with modulation is converted into an electric signal, the output end of the detector is electrically connected with the input end of a receiving side DSP processor, the electric signal is transmitted to the receiving side DSP processor, and the receiving side DSP processor decodes and converts the received 1-path 53.125GBaud PAM4 modulation electric signal into a 4-path 25.78125 Gbps-rate NRZ modulation signal; the output end of the DSP processor at the receiving side is electrically connected with the golden finger, and the NRZ modulation signal is sent to the single board side of the switch through the golden finger; the output end of the DSP processor at the transmitting side is electrically connected with the golden finger, the output end of the DSP processor at the transmitting side is electrically connected with the input end of the EML driver, the DSP processor at the transmitting side carries out a series of processing such as coding, shaping, adjusting and clock recovery on 4 paths of electrical signals with 25.78125Gbps rate received by the golden finger and then outputs 1 path of PAM4 modulation signals of 53.125GBaud to the EML driver; the output end of the EML driver is electrically connected with the EML laser and used for controlling the EML laser to output an optical signal with modulation and transmitting the optical signal to an optical fiber butted with the second optical connector; the microcontroller is electrically connected with the golden finger.

The EML laser is installed between the bottom shell and the upper cover. The PCB is provided with an opening for giving way for mounting an EML laser (EML BOX).

The electrical interface signal rate of the optical module of the embodiment is an NRZ modulation signal of 25.78125Gbps, and the optical interface signal rate is a PAM4 modulation signal of 53.125 GBaud; the PAM4 modulated signal has 4 levels, so 53.125GBaud corresponds to a signal rate of 53.125 x 2=106.25 Gbps.

The electrical signal interface of the optical module is QSFP 28; the wavelength of the optical signal is 1311nm +/-6.5 nm; the optical fiber transmission distance can reach 2 km; temperature range: 0 to 70 ℃.

The package of the patent is QSFP28, the package used by the mature 100G SR4/DR4/LR4/ER4 module in the market is QSFP28, and an operator can not modify the interface of a single board.

Further, a light receiving unit of the optical module adopts a COB (chip on board) process, a PD (PD) and a TIA (three-dimensional interconnect) are pasted on a PCB (printed circuit board) by using conductive silver paste, and then a PD bonding pad and a TIA bonding pad are connected by using a wire bonding technology through gold wires; using the COB process, the quality of the high-speed signal is optimized and space is saved, making the module performance better.

The golden finger is composed of 38 conductive bonding pads, the optical module is connected with the communication interface of the single board of the switch, and all signals are transmitted through the golden finger.

The operation of controlling the DSP chip, the EML driver, the power supply chip and the TIA (transimpedance amplifier) in the optical module is realized by the MCU.

The detector comprises a PD chip and a TIA chip, the TIA chip is electrically connected with the microcontroller, the PD chip and the TIA chip are adhered to the PCB by conductive silver adhesive, the output end of the PD chip is connected with the input end of the TIA chip by a gold thread bonding technology, and the output end of the TIA chip is electrically connected with the input end of the receiving side of the DSP processor. The TIA chip is a transimpedance amplification chip and is used for amplifying a received weak electrical signal, and the PD chip is used for converting a received optical signal into an electrical signal. The PD and the TIA are packaged into a detector through a COB process. And (3) COB process: and (3) directly bonding the bare chip on the printed circuit board by using a chip on board, bonding gold wires, and encapsulating and protecting the chip and the gold wires by using glue.

Further, the optical connector is an LC adapter, and is in butt joint with an external optical fiber, so that light transmitted or received by the optical module is transmitted or received with minimum loss.

Further, the DSP processor is a transceiver and is embedded with an EML driver. The DSP processor adopts DSP + Driver unification chip, and wherein the DSP chip adjusts the plastic with the electrical signal, and EML Driver is Driver chip, produces the electrical signal of taking the modulation signal. The DSP chip and the EML driver are combined to reduce the occupied area of the elements on the PCB, and a larger area is provided for the high-speed differential signal line and the power supply wiring. The MCU is packaged by WLCSP, so that the occupied area can be reduced.

Further, the EML laser (EML Box) uses the unoiled EML COC, i.e. the TEC is not included in the laser (a temperature controller may stabilize the temperature of the EML COC at 52.5 ℃, thereby stabilizing the optical power of the laser). The EML laser is provided with a photoelectric monitoring diode, and the light power of the laser is monitored through an MPD (photoelectric monitoring diode) in the laser, so that the light power changing due to temperature change is compensated according to a P-I (light power-bias current) curve. In the laser verification stage, P-I curves under different temperature conditions are fitted through a large amount of test data, and then the bias current of the laser is changed according to the optical power monitored by MPD, so that the output optical power is stabilized. The light emitting unit of the optical module adopts an uncooled EML COC scheme, and a commercial temperature application environment can be realized without additionally adding a TEC chip. The optical power compensation of the EML device is more difficult than that of a general vcsel device, and a flat area needs to be found according to an EA absorption curve of the EML laser, and the optical power compensation is performed according to the relationship between the optical power and the bias current.

The EML COC process loads an EML device on a SiN substrate and electrically connects the EML device with a Driver driving chip using a wire bonding technique. The SiN substrate is a low-loss and low-refractive-index base material, is not the same as the PCB, and the EML laser is arranged on the SiN substrate through conductive silver adhesive. The traditional optical module adopts a discrete structure, an optical chip is aligned and coupled with an optical fiber through a series of passive coupling devices to complete optical path packaging, the whole packaging link needs more materials and labor cost, meanwhile, the packaging and testing procedures are relatively complex, the automation rate of the packaging process is low, the optical modules need to be manually aligned and coupled one by one in the testing process, and the time and the cost are relatively high. By utilizing the mature silicon wafer processing technology in the traditional semiconductor industry, a large-scale waveguide device can be rapidly processed on the SiN substrate by utilizing an etching process, and the passive optical device can be integrated on the substrate by utilizing the processing technologies such as epitaxial growth and the like. The mode enables the size of the device to be reduced, the material cost, the chip cost and the packaging cost to be optimized, and meanwhile, the batch test is more convenient.

The inner wall of the shell is provided with a heat dissipation boss, the PCB is in contact with the heat dissipation boss, and the heat dissipation boss and the PCB are filled with heat conduction materials. The heat dissipation process of the optical module is another challenge by using the EML COC process, when the shell temperature is 70 ℃, the maximum temperature on the PCB reaches 105 ℃ by using the traditional manufacturing process, and the maximum temperature which can be borne by an EML COC device is 75 ℃, so that the heat dissipation speed is improved by adopting the process of embedding the copper block in the PCB in the patent, the boss is designed on the tube shell of the optical module, the PCB below the EML COC optical device can be in contact with the boss, and in order to increase the contact area, the boss and the PCB are filled with the silicone grease heat conduction gel. After the heat dissipation design, the optical module can be ensured to normally work in a commercial temperature application environment.

The PCB board has the radiating block buried underground locally, makes heating element directly paste the dress on the radiating block, and the thermal conductivity of radiating block is higher than the thermal conductivity of PCB panel, and the heat is gone out through the radiating block conduction. The heat dissipation piece adopts the copper billet, and this embodiment adopts buries the copper billet technology in the PCB: the thermal conductivity of copper is higher than that of the PCB, so that the heat dissipation speed can be improved. The copper block is embedded in the position where the PCB local heating component is large, so that the heating component can be directly attached to the copper block, and heat is conducted out through the copper block. The commonly used heat dissipation method comprises: manufacturing a circuit board by using a metal substrate, and welding the metal substrate on the circuit board; however, the two processes have the disadvantages of large consumption of metal materials, complex manufacturing process, high cost, large volume and the like.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. The utility model provides a single channel transmission rate is 100 Gbps's optical module, includes casing, PCB board and optical connector, and the PCB board sets up in the casing, and the tip of PCB board is provided with the golden finger, and the golden finger is the electric interface of optical module and switch veneer communication, optical connector sets up in the tip of casing for with external optic fibre butt joint, optical connector and golden finger are located the both ends of casing, its characterized in that respectively: the PCB board is provided with a power supply module, a microcontroller, a DSP processor, an EML driver and a detector, the power supply module is used for supplying power to the whole optical module, the microcontroller is respectively and electrically connected with the DSP processor and the EML driver, the detector is for receiving a modulated optical signal transmitted by an optical fiber that interfaces with the first optical connector, and converts the received modulated optical signal into an electrical signal, the output end of the detector is electrically connected with the input end of the receiving side DSP processor, the output end of the receiving side DSP processor is electrically connected with the golden finger, the output end of the transmitting side DSP processor is electrically connected with the input end of the EML driver, the output end of the EML driver is electrically connected with the EML laser, the optical fiber is used for controlling the EML laser to output an optical signal with modulation and transmitting the optical signal to be butted with the second optical connector; the microcontroller is electrically connected with the golden finger; the PCB board part has buried the radiating block underground, makes the direct dress of pasting of heating element on the radiating block, and the heat conductivity of radiating block is higher than the heat conductivity of PCB panel, and the heat conducts away through the radiating block, shells inner wall is equipped with the heat dissipation boss, PCB board and heat dissipation boss contact use the heat conduction material to fill between heat dissipation boss and the PCB board.

2. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: the heat dissipation block is a copper block.

3. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: and the heat conduction material filled between the heat dissipation boss and the PCB is silicone grease heat conduction gel.

4. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: the detector comprises a PD chip and a TIA chip, the TIA chip is electrically connected with the microcontroller, the PD chip and the TIA chip are adhered to the PCB by conductive silver adhesive, the output end of the PD chip is connected with the input end of the TIA chip by a gold thread bonding technology, and the output end of the TIA chip is electrically connected with the input end of the receiving side of the DSP processor.

5. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: the optical connector is an LC adapter.

6. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: the DSP processor is integrated with the receiving and sending functions and is internally embedded with an EML driver.

7. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: and the microcontroller is packaged by WLCSP.

8. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: the EML laser was loaded onto a SiN substrate and electrically connected to the EML driver using gold wire bonding techniques.

9. The optical module with a single channel transmission rate of 100Gbps according to claim 1, wherein: the EML laser does not contain the TEC; the EML laser is internally provided with a photoelectric monitoring diode which is used for monitoring the optical power of the EML laser, and the EML laser changes the bias current of the laser according to the optical power-bias current curve under different temperature conditions and stabilizes the output optical power.