Patent Publication Number: US-2022216670-A1

Title: Optical module and temperature control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of International Application No. PCT/CN2021/101605 filed on Jun. 22, 2021, which claims priority to Chinese Patent Application No. 202011141727.3 filed on Oct. 22, 2020, Chinese Patent Application No. 202011164206.X filed on Oct. 27, 2020. The entirety of each is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of optical communication technologies, and in particular, to an optical module and a temperature control method thereof. 
     BACKGROUND 
     In the development process of high-speed optical communication products, with the improvement of signal transmission rate, people are having higher requirements for cost reduction. In traditional optical communication products, the light-emitting device usually adopts a hermetically sealed cover to encapsulate various optoelectronic devices, so as to prevent moisture from entering the inside of the cover and ensure that the entire light-emitting device can operate normally in high temperature and high humidity environments. However, the hermetically sealed cover is very expensive and cannot meet people&#39;s increasingly higher requirements for cost reduction. Therefore, the non-hermetic sealing method has become the main development direction to replace the hermetic sealing method due to its lower cost and more flexible design. 
     SUMMARY 
     In one aspect, an optical module is provided. The optical module includes a shell, a circuit board, a light-emitting device, a sensor assembly, and a processor. The circuit board is disposed in the shell. The light-emitting device is disposed in the shell, and includes a non-hermetically sealed cover, a laser chip and a thermo electric cooler. The laser chip is disposed in the cover and on the thermo electric cooler, and is configured to emit an optical signal. The thermo electric cooler is disposed in the cover, and is configured to adjust a temperature of the heat exchange surface of the thermo electric cooler connected to the laser chip. The sensor assembly is disposed on the circuit board, and is configured to detect ambient data inside the optical module, the ambient data including at least ambient humidity. The processor is disposed on the circuit board, and is configured to receive the ambient data detected by and sent from the sensor assembly, and control the thermo electric cooler to adjust the temperature of the heat exchange surface of the thermo electric cooler to a target temperature according to the ambient data. 
     In another aspect, a temperature control method of an optical module is provided. The method includes: obtaining, by a sensor assembly, ambient data inside the optical module, and sending, by the sensor assembly, the obtained ambient data to a processor, the ambient data including at least ambient humidity; and receiving, by the processor, the ambient data obtained by the sensor assembly, and controlling, by the processor, the thermo electric cooler to adjust a temperature of a heat exchange surface of a thermo electric cooler to a target temperature according to the ambient data. 
     In yet another aspect, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium has stored thereon computer program instructions that, when run on a processor, cause the processor to execute the above temperature control method of the optical module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe technical solutions in the present disclosure more clearly, accompanying drawings to be used in some embodiments of the present disclosure will be introduced briefly below. However, the accompanying drawings to be described below are merely accompanying drawings of some embodiments of the present disclosure, and a person of ordinary skill in the art may obtain other drawings according to these drawings. In addition, the accompanying drawings to be described below may be regarded as schematic diagrams, and are not limitations on an actual size of a product, an actual process of a method and an actual timing of a signal involved in the embodiments of the present disclosure. 
         FIG. 1  is a connection diagram of an optical communication system, in accordance with some embodiments; 
         FIG. 2  is a structural diagram of an optical network terminal, in accordance with some embodiments; 
         FIG. 3  is a structural diagram of an optical module, in accordance with some embodiments; 
         FIG. 4  is an exploded structural diagram of an optical module, in accordance with some embodiments; 
         FIG. 5A  is a structural diagram of an optical module with an upper shell, a lower shell, and an unlocking component removed, in accordance with some embodiments; 
         FIG. 5B  is a diagram of an internal structure of a light-emitting device, in accordance with some embodiments; 
         FIG. 6  is a structural diagram of a sensor assembly, in accordance with some embodiments; 
         FIG. 7  is a diagram showing an electrical connection between a sensor assembly and a microcontroller unit (MCU), in accordance with some embodiments; 
         FIG. 8  is a diagram showing a relationship between ambient humidity and dew-point temperature of an optical module under different ambient temperatures, in accordance with some embodiments; 
         FIG. 9  is a flow diagram of a temperature control method of an optical module, in accordance with some embodiments; and 
         FIG. 10  is a flow diagram of another temperature control method of an optical module, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Technical solutions in some embodiments of the present disclosure will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are merely some but not all embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure shall be included in the protection scope of the present disclosure. 
     Unless the context requires otherwise, throughout the description and the claims, the term “comprise” and other forms thereof such as the third-person singular form “comprises” and the present participle form “comprising” are construed as an open and inclusive meaning, i.e., “including, but not limited to”. In the description of the specification, the terms such as “one embodiment”, “some embodiments”, “exemplary embodiments”, “example”, “specific example” or “some examples” are intended to indicate that specific features, structures, materials, or characteristics related to the embodiment(s) or example(s) are included in at least one embodiment or example of the present disclosure. Schematic representations of the above terms do not necessarily refer to the same embodiment(s) or example(s). In addition, the specific features, structures, materials, or characteristics may be included in any one or more embodiments or examples in any suitable manner. 
     Hereinafter, the terms “first” and “second” are used for descriptive purposes only, and are not to be construed as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. Thus, features defined with “first” and “second” may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, “a plurality of/the plurality of” means two or more unless otherwise specified. 
     In the description of some embodiments, the terms “coupled”, “connected” and derivatives thereof may be used. For example, the term “connected” may be used when describing some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. For another example, the term “coupled” may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact. However, the term “coupled” or “communicatively coupled” may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content herein. 
     The phrase “At least one of A, B, and C” has the same meaning as the phrase “at least one of A, B, or C”, and both include the following combinations of A, B, and C: only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and a combination of A, B and C. 
     The phrase “A and/or B” includes the following three combinations: only A, only B, and a combination of A and B. 
     As used herein, depending on the context, the term “if” is optionally construed as “when” or “in a case where” or “in response to determining” or “in response to detecting”. Similarly, depending on the context, the phrase “if it is determined . . . ” or “if [the stated condition or event] is detected” is optionally construed as “when determining . . . ” or “in response to determining . . . ” or “in a case where [the stated condition or event] is detected” or “in response to detecting [the stated condition or event]”. 
     The phrase “applicable to” or “configured to” as used herein indicates an open and inclusive expression, which does not exclude devices that are applicable to or configured to perform additional tasks or steps. 
     In addition, the phrase “based on” as used herein indicates openness and inclusiveness, since processes, steps, calculations or other actions “based on” one or more of the stated conditions or values may be based on additional conditions or exceed the stated values in practice. 
     As used herein, the term “about”, “substantially” or “approximately” includes a stated value and an average value within an acceptable range of deviation of a particular value. The acceptable range of deviation is determined by a person of ordinary skill in the art in consideration of the measurement in question and errors associated with the measurement of a particular quantity (i.e., limitations of a measurement system). 
     In optical communication technology, an optical signal is used to carry information to be transmitted, and the optical signal carrying the information is transmitted to an information processing device such as a computer through an information transmission device such as an optical fiber or an optical waveguide, so as to achieve information transmission. Due to the passive transmission characteristic of the optical signal when being transmitted through the optical fiber or the optical waveguide, low-cost and low-loss information transmission may be achieved. In addition, since a signal transmitted by the information transmission device such as the optical fiber or the optical waveguide is the an optical signal, and a signal that may be recognized and processed by the information processing device such as a computer is an electrical signal, in order to establish information connection between the information transmission device such as the optical fiber or the optical waveguide and the information processing device such as the computer, there is a need to achieve interconversion between the electrical signal and the optical signal. Common information processing devices include a router, a switch, and an electronic computer. 
     In the field of optical fiber communication technology, an optical module may achieve interconversion between the optical signal and the electrical signal. The optical module includes an optical port and an electrical port. The optical module achieves optical communication with the information transmission device such as the optical fiber or the optical waveguide through the optical port, and the optical module achieves electrical connection with an optical network terminal (e.g., an optical modem) through the electrical port. The electrical connection is mainly to implement power supply, Inter-Integrated circuit (I2C) signal transmission, data signal transmission, and grounding functions. The optical network terminal transmits the electrical signal to the information processing device such as a computer through a network cable or wireless fidelity (\Ni-Fi). 
       FIG. 1  is a connection diagram of an optical communication system, in accordance with some embodiments. As shown in  FIG. 1 , the optical communication system includes a remote server  1000 , a local information processing device  2000 , an optical network terminal  100 , an optical module  200 , an optical fiber  101  and a network cable  103 . 
     An end of the optical fiber  101  is connected to the remote server  1000 , and another end thereof is connected to the optical network terminal  100  through the optical module  200 . The optical fiber itself supports long-distance signal transmission, for example, signal transmission over several kilometers (6 kilometers to 8 kilometers). On this basis, if repeaters are used, theoretically, it may be possible to achieve infinite-distance transmission. Therefore, in a typical optical communication system, a distance between the remote server  1000  and the optical network terminal  100  may typically reach several kilometers, dozens of kilometers, or hundreds of kilometers. 
     An end of the network cable  103  is connected to the local information processing device  2000 , and another end thereof is connected to the optical network terminal  100 . The local information processing device  2000  includes one or more of a router, a switch, a computer, a mobile phone, a tablet computer or a television. 
     A physical distance between the remote server  1000  and the optical network terminal  100  is greater than a physical distance between the local information processing device  2000  and the optical network terminal  100 . Connection between the local information processing device  2000  and the remote server  1000  is achieved by the optical fiber  101  and the network cable  103 , and connection between the optical fiber  101  and the network cable  103  is achieved by the optical module  200  and the optical network terminal  100 . 
     The optical network terminal  100  includes a housing in a substantially cuboid shape, and an optical module interface  102  and a network cable interface  104  that are disposed on the housing. The optical module interface  102  is configured for connecting the optical module  200 , so that a bidirectional electrical signal connection is established between the optical network terminal  100  and the optical module  200 . The network cable interface  104  is configured for connecting the network cable  103 , so that a bidirectional electrical signal connection is established between the optical network terminal  100  and the network cable  103 . Connection between the optical module  200  and the network cable  103  is established through the optical network terminal  100 . For example, the optical network terminal  100  transmits an electrical signal from the optical module  200  to the network cable  103 , and transmits an electrical signal from the network cable  103  to the optical module  200 . Therefore, the optical network terminal  100 , as a master monitor of the optical module  200 , may monitor operation of the optical module  200 . In addition to the optical network terminal  100 , the master monitors of the optical module  200  may further include an optical line terminal (OLT). 
     The optical module  200  includes an electrical port and an optical port. The optical port is configured for connecting the optical fiber  101 , so that a bidirectional optical signal connection between the optical module  200  and the optical fiber  101  is established; and the electrical port is configured for connecting the optical network terminal  100 , so that a bidirectional electrical signal connection is established between the optical module  200  and the optical network terminal  100 . The optical module  200  may achieve interconversion between the optical signal and the electrical signal, so that a connection is established between the optical fiber  101  and the optical network terminal  100 . For example, an optical signal from the optical fiber  101  is converted into an electrical signal by the optical module  200 , and then the electrical signal is input into the optical network terminal  100 ; an electrical signal from the optical network terminal  100  is converted into an optical signal by the optical module  200 , and then the optical signal is input into the optical fiber  101 . Since the optical module  200  is a tool for achieving interconversion between the optical signal and the electrical signal, and doesn&#39;t have a data processing function, the information does not change in the above photoelectric conversion process. 
     A bidirectional signal transmission channel has been established between the remote server  1000  and the local information processing device  200  through the optical fiber  101 , the optical module  200 , the optical network terminal  100  and the network cable  103 . 
       FIG. 2  is a structural diagram of an optical network terminal, in accordance with some embodiments. In order to clearly show a connection relationship between the optical module  200  and the optical network terminal  100 ,  FIG. 2  only shows a structure of the optical network terminal  100  that is related to the optical module  200 . As shown in  FIG. 2 , the optical network terminal  100  further includes a circuit board  105  disposed in the housing, a cage  106  disposed on a surface of the circuit board, a heat sink  107  disposed on the cage  106 , and an electrical connector disposed inside the cage  106 . The electrical connector is configured for connecting the electrical port of the optical module  200 . The heat sink  107  has protruding portions such as fins for increasing a heat dissipation area. 
     The optical module  200  is inserted into the cage  106  of the optical network terminal  100 , and is fixed by the cage  106 . Heat generated by the optical module  200  is conducted to the cage  106  and is then dissipated through the heat sink  107 . After the optical module  200  is inserted into the cage  106 , the electrical port of the optical module  200  is connected to the electrical connector in the cage  106 , so that a bidirectional electrical signal connection is established between the optical module  200  and the optical network terminal  100 . In addition, the optical port of the optical module  200  is connected to the optical fiber  101 , so that a bidirectional optical signal connection is established between the optical module  200  and the optical fiber  101 . 
       FIG. 3  is a structural diagram of an optical module, in accordance with some embodiments, and  FIG. 4  is an exploded structural diagram of an optical module, in accordance with some embodiments. As shown in  FIGS. 3 and 4 , the optical module  200  includes a shell, a circuit board  300  disposed inside the shell, a light-emitting device  400  and a light-receiving device  500 . 
     The shell includes an upper shell  201  and a lower shell  202 . The upper shell  201  covers the lower shell  202  to form the shell having two openings; and an outer contour of the shell is generally in a cuboid shape. 
     In some embodiments, the lower shell  202  includes a bottom plate  2021  and two lower side plates  2022  that are located on two sides of the bottom plate  2021  and disposed perpendicular to the bottom plate  2021 ; the upper shell  201  includes a cover plate  2011 , and the cover plate  2011  covers the two lower side plates  2022  of the lower shell  202  to form the shell. 
     In some embodiments, the lower shell  202  includes a bottom plate  2021  and two lower side plates  2022  that are located on two sides of the bottom plate  2021  and disposed perpendicular to the bottom plate  2021 ; the upper shell  201  includes a cover plate  2011  and two upper side plates that are located on two sides of the cover plate  2011  and disposed perpendicular to the cover plate  2011 . The two upper side plates are combined with the two lower side plates  2022  respectively, so that the upper shell  201  covers the lower shell  202 . 
     A direction in which a connection line between the two openings  204  and  205  extends may be the same as a longitudinal direction of the optical module  200 , or may not be the same as the longitudinal direction of the optical module  200 . For example, the opening  204  is located at an end (a left end in  FIG. 3 ) of the optical module  200 , and the opening  205  is also located at an end (a right end in  FIG. 3 ) of the optical module  200 . Alternatively, the opening  204  is located at an end of the optical module  200 , and the opening  205  is located at a side of the optical module  200 . The opening  204  is the electrical port, and a connecting finger  301  of the circuit board  300  extends out from the electrical port  204 , and is inserted into the master monitor (e.g., the optical network terminal  100 ). The opening  205  is the optical port, and is configured for connecting the external optical fiber  101 , so that the optical fiber  101  is connected to the light-emitting device  400  and the light-receiving device  500  in the optical module  200 . 
     By adopting an assembly mode of combining the upper shell  201  and the lower shell  202 , it may be easier to install the circuit board  300 , the light-emitting device  400 , the light-receiving device  500  and other optical devices into the shell, and the upper shell  201  and the lower shell  202  may provide sealing and protection for these devices. In addition, when the circuit board  300 , the light-emitting device  400 , the light-receiving device  500  and other devices are assembled, it may be easier to arrange the positioning elements, heat dissipation elements, and electromagnetic shielding elements of these devices, which facilitates automated production. 
     In some embodiments, the upper shell  201  and the lower shell  202  are made of a metallic material, which helps achieve electromagnetic shielding and heat dissipation. 
     In some embodiments, the optical module  200  further includes an unlocking component  203  located outside the shell. The unlocking component  203  is configured to implement a fixed connection between the optical module  200  and the master monitor, or to release the fixed connection between the optical module  200  and the master monitor. 
     For example, the unlocking component  203  is located outside the two lower side plates  2022  of the lower shell  202 , and has an engagement element that is matched with the cage  106  of the master monitor. When the optical module  200  is inserted into the cage  106 , the optical module  200  is fixed in the cage  106  through the engagement element of the unlocking component  203 . When the unlocking component  203  is pulled, the engagement element of the unlocking component  203  moves along with the unlocking component  203 , and then a connection relationship between the engagement element and the master monitor is changed to release the engagement between the optical module  200  and the master monitor, so that the optical module  200  may be pulled out of the cage  106 . 
     The circuit board  300  includes circuit traces, electronic elements, chips, etc. Through the circuit traces, the electronic elements and the chips are connected together according to circuit design, so as to implement power supply, electrical signal transmission, and grounding functions. The electronic elements may include, for example, a capacitor, a resistor, a triode, and a metal-oxide-semiconductor field-effect transistor (MOSFET). The chips may include, for example, a microcontroller unit (MCU), a laser driving chip, a limiting amplifier, a clock and data recovery (CDR) chip, a power management chip or a digital signal processing (DSP) chip. 
     The circuit board  300  is generally a rigid circuit board. Since it is made of a relatively hard material, the rigid circuit board may also have a support function. For example, the rigid circuit board may stably support the electronic elements and the chips, and may also be inserted into the electrical connector in the cage  106  of the master monitor. 
     The circuit board  300  further includes a connecting finger  301  formed on an end surface thereof, and the connecting finger  301  is composed of a plurality of independent pins. The circuit board  300  is inserted into the cage  106 , and is conductively connected to the electrical connector in the cage  106  through the connecting finger  301 . The connecting finger  301  may be disposed on only one surface (e.g., an upper surface shown in  FIG. 4 ) of the circuit board  300 , or may be disposed on both the upper and lower surfaces of the circuit board  300  to adapt to an occasion where a large number of pins are needed. The connecting finger  301  is configured to establish an electrical connection with the master monitor to implement power supply, grounding, I2C signal transmission, and data signal transmission functions. 
     Of course, flexible circuit boards are also used in some optical modules. A flexible circuit board is generally used in conjunction with a rigid circuit board as a supplement for the rigid circuit board. 
     For a high-speed optical module, such as a 400G SR4 (maximum transmission distance: 500 meters) optical module, a 400G LR4 (maximum transmission distance: 10 kilometers) optical module, a 400G ER4 (maximum transmission distance: 40 kilometers) optical module, and other optical modules, as the signal transmission rate increases, people are having higher requirements for cost reduction. Traditional light-emitting device usually adopts a hermetically sealed cover to ensure the air tightness of the light-emitting device, so that the entire light-emitting device can operate normally in high temperature and high humidity environments. 
     The 400G SR4 optical module, 400G LR4 optical module and 400G ER4 optical module refer to optical modules that adopt 4 optical signal transmission channels with a transmission rate of 106 Gbit/s on the optical port side, and 8 electrical signal transmission channels with a transmission rate of 53 Gbit/s on the electrical port side, so as to realize a signal transmission rate of 400 Gbit/s. SR, LR and ER are used to classify the optical modules with a transmission rate of 400 Gbit/s according to the signal transmission distance. SR is short for “short range”, LR is short for “long range” and ER is short for “extended range”. 
     However, the hermetically sealed cover is very expensive and cannot meet people&#39;s increasingly stringent requirements for cost reduction. Therefore, the non-hermetic sealing method has become the main development direction to replace the hermetic sealing method due to its lower cost and more flexible design. 
     The light-emitting device  400  includes a non-hermetically sealed cover. For example, the flexible circuit board is inserted into the cover. An end of the flexible circuit board is electrically connected to a laser chip and other optical devices, and another end thereof is electrically connected to the circuit board  300 . Since the cover has an opening that allows the flexible circuit board to pass through, the cover of the light-emitting device  400  becomes a cover that is not hermetically sealed. Or, the circuit board  300  is directly inserted into the cover, and the laser chip and other optical devices are disposed on the circuit board  300 . Since the cover has an opening that allows the circuit board  300  to pass through, the cover of the light-emitting device  400  becomes a cover that is not hermetically sealed. 
     However, in the non-hermetically sealed structure of the light-emitting device  400 , especially in a case where there is a thermo electric cooler (TEC), the laser chip and other optical devices are disposed on a heat exchange surface of the TEC. The TEC cools or heats the laser chip and other optical devices through the heat exchange surface, so as to decrease or increase the temperature of the laser chip and other optical devices, and ensure the normal operation of the laser chip and other optical devices. When the heat exchange surface of the TEC cools the laser chip and other optical devices, the heat exchange surface of the TEC usually has a low fixed temperature. In high temperature and high humidity environments, there is a slight air leakage in the cover due to the non-hermetically sealed structure of the light-emitting device  400 . After a certain period of time, when the temperature of the heat exchange surface of the TEC drops below a dew point of the moisture inside the cover of the light-emitting device  400 , the surfaces of key optical devices on the TEC will be covered with dew. As a result, the output power of the light-emitting device will decrease, and the light-emitting device may not even operate normally. 
     In order to solve the above problems, some embodiments of the present disclosure provide an optical module, which can monitor humidity data inside the optical module in real time, and adjust the cooling or heating temperature of the TEC correspondingly according to the humidity data. As a result, the key optical devices (e.g., a laser chip) in the light-emitting device  400  may operate at a temperature above the dew point inside the cover of the light-emitting device  400 ; therefore, it may be possible to prevent condensation on the surfaces of the key optical devices, and ensure that the entire optical module operates normally. 
       FIG. 5A  is a structural diagram of an optical module with an upper shell  201 , a lower shell  202 , and an unlocking component  203  removed, in accordance with some embodiments. As shown in  FIG. 5A , the optical module  200  further includes a microcontroller unit (MCU)  310 , a power management chip  320 , a sensor assembly  330 , and a driving chip  340  of the TEC. The MCU  310 , the power management chip  320  and the sensor assembly  330  are all disposed on the circuit board  300 . The MCU  310  and the sensor assembly  330  are both electrically connected to the power management chip  320 . The power management chip  320  is connected to the master monitor to adjust a voltage provided by the master monitor, so as to supply power to the MCU  310  and the sensor assembly  330 . 
     The sensor assembly  330  is configured to detect ambient data inside the optical module  200 . A communication signal interface of the sensor assembly  330  is connected to a communication signal interface of the MCU  310 . The MCU  310  is configured to receive the ambient data detected by the sensor assembly  330 , and control a cooling temperature or heating temperature of the TEC  401  (as shown in  FIG. 5B ) according to the ambient data, so that the cooling temperature or heating temperature of the TEC  401  may allow the key optical devices disposed on the TEC  401  to operate at an temperature above the dew point inside the cover, so as to prevent condensation on the surfaces of the key optical devices and ensure normal operation of the entire optical module. 
       FIG. 5B  is a diagram of an internal structure of the light-emitting device  400 , in accordance with some embodiments; and the cover of the light-emitting device  400  is omitted in  FIG. 5B . As shown in  FIG. 5B , the light-emitting device  400  includes a TEC  401 , a laser chip  402 , a focusing lens  403 , an optical fiber adapter  404  and an internal optical fiber  405  that are located inside the cover. 
     The TEC  401  is disposed inside the cover, and is a main device for adjusting temperature in the optical module. A plurality of (four, to form four optical signal transmission channels) laser chips  402  are disposed on a surface of the TECs  401 . The TECs  401  are configured to adjust a temperature of the heat exchange surfaces thereof connected to the laser chips  402 ; for example, the TECs  401  are configured to conduct the heat generated by the plurality of laser chips  402  to the cover, so that the heat is conducted to the outside of the optical module  200  through the cover; for another example, the TECs  401  are configured to maintain the temperature of the heat exchange surfaces thereof so as to avoid condensation. The plurality of laser chips  402  are configured to emit optical signals. A plurality of focusing lenses  403  are in one-to-one correspondence with the plurality of laser chips  402 , and are configured to converge light emitted by corresponding laser chips  402 , so that the light is subsequently coupled with the internal optical fibers  405  in the optical fiber adapters  404 . The internal optical fibers  405  are connected to an external optical fiber that is connected to the optical port  205  of the optical module  200 , so as to realize transmission of optical signals to the outside of the optical module  200 . 
       FIG. 6  is a structural diagram of a sensor assembly, in accordance with some embodiments. Referring to  FIG. 6 , in some embodiments, in a case where the sensor assembly  330  is configured to obtain the ambient humidity and ambient temperature inside the optical module  200  in real time, the sensor assembly  330  includes at least a humidity sensor  331  and a temperature sensor  332 . The humidity sensor  331  is configured to obtain ambient humidity data inside the optical module  200  in real time; and the temperature sensor  332  is configured to obtain ambient temperature data inside the optical module  200  in real time. The ambient data detected by the sensor assembly  330  includes ambient humidity and ambient temperature inside the optical module  200 . For example, the ambient humidity is relative humidity. The MCU  310  generates a control signal according to the obtained ambient humidity and ambient temperature, and transmits the control signal to the driving chip  340  of the TEC. The driving chip  340  of the TEC drivers the TEC  401  to decrease or increase the temperature of the heat exchange surface of the TEC, so as to adjust the temperature of the laser chip  402  and other optical devices on the heat exchange surface of the TEC, and avoid condensation on the laser chip and other optical devices. 
     In some embodiments, in a case where the sensor assembly  330  is configured to only detect the ambient humidity inside the optical module  200 , the sensor assembly  330  includes at least a humidity sensor  331 , but does not include a temperature sensor. The ambient data detected by the sensor assembly  330  includes the ambient humidity inside the optical module  200 . In this case, the MCU  310  includes a temperature sensor, and the MCU  310  is able to detect the ambient temperature inside the optical module  200  in real time. The sensor assembly  330  transmits the detected ambient data to the MCU  310 , and the MCU  310  generates a control signal according to the ambient temperature detected by itself and the obtained ambient humidity, and transmits the control signal to the driving chip  340  of the TEC. The driving chip  340  of the TEC drives the TEC to decrease or increase the temperature of the heat exchange surface of the TEC, so as to adjust the temperature of the laser chip and other optical devices on the heat exchange surface of the TEC, and avoid condensation on the laser chip and other optical devices. 
     In some embodiments, in a case where neither the sensor assembly  330  nor the MCU  310  includes a temperature sensor, the optical module  200  may include an additional temperature sensor. The MCU  310 , the sensor assembly  330  and the additional temperature sensor are all disposed on the circuit board  300 . The additional temperature sensor is electrically connected to the power management chip  320 ; and the power management chip  320  supplies power to the additional temperature sensor, so that the additional temperature sensor detects the temperature inside the optical module  200  in real time. The additional temperature sensor is further communicatively connected to the MCU  310 , so as to transmit the detected ambient temperature data to the MCU  310 . 
     In some embodiments, as shown in  FIG. 6 , in a case where the sensor assembly  330  includes the humidity sensor  331  and the temperature sensor  332 , the humidity sensor  331  and the temperature sensor  332  transmit the ambient humidity and ambient temperature obtained in real time to the MCU  310  through an I2C interface  335  of the sensor assembly  330 ; the MCU  310  generates a control signal after processing the received ambient humidity and ambient temperature, and the control signal controls the cooling or heating temperature of the heat exchange surface of the TEC. 
     Since the cover of the light-emitting device  400  is a non-hermetically sealed cover, the air inside the optical module  200  is connected to the air inside the light emitting device  400 . Therefore, the ambient humidity data and the ambient temperature data detected by the humidity sensor  331  and the temperature sensor  332  are the ambient humidity data and the ambient temperature data inside the light-emitting device  400 . 
     In some embodiments, the driving chip  340  of the TEC is disposed on the circuit board  300 , and the MCU  310  and the TEC  401  which is in the light-emitting device  400  are both electrically connected to the driving chip  340  of the TEC. The MCU  310  transmits the control signal to the driving chip  340  of the TEC, and the driving chip  340  of the TEC drives the TEC  401  to adjust the cooling or heating temperature according to the control signal, so as to adjust the operation temperature of the laser chip  402  on the TEC  401  and other optical devices. 
     In some embodiments, the driving chip of the TEC is integrated in the MCU  310 , and the TEC  401  in the light-emitting device  400  is electrically connected to the driving chip of the TEC in the MCU  310 . 
     It will be noted that, the optical module  200  is not limited to using the MCU  310  as a processor. In some embodiments, the processor includes a central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), and may be configured to execute corresponding operations described in the processor when the processor executes the program stored in the non-transitory computer readable medium coupled to the processor. The non-transitory computer-readable storage media may include a magnetic storage device (e.g., a hard disk, floppy disk or magnetic tape), a smart card, or a flash memory device (e.g., an erasable programmable read-only memory (EPROM)), card, stick, or keyboard driver). 
       FIG. 6  is a structural diagram of a sensor assembly  330 , in accordance with some embodiments. As shown in  FIG. 6 , the sensor assembly  330  includes a humidity sensor  331 , a temperature sensor  332 , an analog-to-digital converter  333 , an internal processor  334  and an I2C interface  335 . An output end of the humidity sensor  331  and an output end of the temperature sensor  332  are both connected to an input end of the analog-to-digital converter  333 ; an output end of the analog-to-digital converter  333  is connected to an input end of the internal processor  334 ; an output end of the internal processor  334  is connected to an end of the I2C interface; the I2C interface is connected to a communication signal interface of the MCU  310  through an I2C line (e.g., a serial clock (SCL) line, or a serial data (SDA) line). 
     The ambient humidity data and the ambient temperature data detected by the humidity sensor  331  and the temperature sensor  332  are converted into digital signals by the analog-to-digital converter  333 ; after the digital signals are transmitted to the internal processor  334 , the internal processor  334  converts the digital signals into protocol signals complying with the I2C transmission protocol, and the protocol signals are transmitted to the MCU  310  through the I2C line. 
     In some embodiments, the sensor assembly  330  further includes an internal memory  336 . An input end of the internal memory  336  is connected to the output end of the internal processor  334 , and is configured to store the ambient humidity and the ambient temperature processed by the internal memory  334  and relevant data information required for detecting the ambient humidity and the ambient temperature, so as to facilitate subsequent checks. 
     Herein, the processor included in the sensor assembly  330  is referred to as an internal processor, and the memory included in the sensor assembly  330  is referred to as an internal memory. In some embodiments, the internal processor  334  includes a microprocessor, an application specific integrated circuit (ASIC), etc. In some embodiments, the internal memory includes a smart card, or a flash memory device (e.g., erasable programmable read-only memory (EPROM), a card, a stick, or a keyboard driver), etc. 
       FIG. 7  is a diagram showing an electrical connection between the sensor assembly  330  and the MCU  310 , in accordance with some embodiments. As shown in  FIG. 7 , the sensor assembly  330  includes a first solder joint  51 , a second solder joint S 2 , a third solder joint S 3  and a fourth solder joint S 4 . The first solder joint  51  is electrically connected to the power management chip  320  through a wire bonding process; the second solder joint S 2  is connected to a ground wire through a wire bonding process; the third solder joint S 3  connects the SCL line to the I2C interface in the sensor assembly  330  through a wire bonding process, and the I2C interface in the sensor assembly  330  is connected to the communication signal interface of the MCU  310  through the SCL line; the fourth solder joint S 4  connects the SDA line to the I2C interface in the sensor assembly  330  through a wire bonding process, and the I2C interface in the sensor assembly  330  is connected to the communication signal interface of the MCU  310  through the SDA line. 
     After the sensor assembly  330  is fixed on the circuit board  300 , an end of the bonding wire is soldered to the first solder joint S 1 , and another end of the bonding wire is connected to the power management chip  320 , so as to realize an electrical connection between the sensor assembly  330  and the power management chip  320 ; an end of another bonding wire is soldered to the second solder joint S 2 , and another end of the another bonding wire is connected to the ground wire, so as to realize an electrical connection between the sensor assembly  330  and the ground wire; an end of the SCL line is soldered to the third solder joint S 3 , and another end of the SCL line is connected to the communication signal interface of the MCU  310 ; an end of the SDA line is soldered to the fourth solder joint S 4 , and another end of the SDA line is connected to the communication signal interface of the MCU  310 , so as to realize an electrical connection between the sensor assembly  330  and the MCU  310 . 
     In order to facilitate the connection between the sensor assembly  330  and the MCU  310  through the I2C interface, the MCU  310  further includes an I2C interface, and the I2C interface of the sensor assembly  330  is connected to the I2C interface of the MCU  310  through the SCL line and the SDA line. The MCU  310  includes a fifth solder joint S 5  and a sixth solder joint S 6 . The fifth solder joint S 5  connects the SCL line to the I2C interface of the MCU  310  through a wire bonding process, and the sixth solder joint S 6  connects the SDA line to the I2C interface of the MCU  310  through a wire bonding process. When the I2C interface of the sensor assembly  330  is connected to I2C interface of the MCU  310 , an end of the SCL line is soldered to the third solder joint S 3  of the sensor assembly  330 , and another end of the SCL line is soldered to the fifth solder joint S 5  of the MCU  310 ; an end of the SDA line is soldered to the fourth solder joint S 4  of the sensor assembly  330 , and another end of the SDA line is soldered to the sixth solder joint S 6  of the MCU  310 , so as to realize the connection between the I2C interface of the sensor assembly  330  and the I2C interface of the MCU  310 . 
     The MCU  310  further includes a seventh solder joint S 7  and an eighth solder joint S 8 . The seventh solder joint S 7  is electrically connected to the power management chip  320  through a wire bonding process, and the eighth solder joint S 8  is connected to the ground wire through a wire bonding process. 
     In some embodiments, the I2C interface of the sensor assembly  330  adopts an open drain mechanism. The SCL line and the SDA line can only output a signal of low level, but cannot actively output a signal of high level. Therefore, a low level output from the I2C interface of the sensor assembly  330  can only be pulled up to a high level by a pull-up resistor, so as to match the logic level of the MCU  310 . In a case where the I2C interface of the sensor assembly  330  is connected to the I2C interface of the MCU  310  through the SCL line and the SDA line, the optical module  200  further includes a first pull-up resistor R 1  and a second pull-up resistor R 2  that are disposed on the I2C bus. The first pull-up resistor R 1  is connected to the SCL line, the second pull-up resistor R 2  is connected to the SDA line, and the first pull-up resistor R 1  and the second pull-up resistor R 2  are arranged in parallel. An end of the first pull-up resistor R 1  is connected to the power management chip  320 , and another end thereof is connected to the SCL line. An end of the second pull-up resistor R 2  is connected to the power management chip  320 , and another end thereof is connected to the SDA line. 
     In some embodiments, the sensor assembly  330  is disposed at a position, away from the light-emitting device  400 , of the circuit board  300 , and is electrically connected to the MCU  310 , the power management chip  320  and the ground wire. The sensor assembly  330  is configured to detect the ambient humidity and the ambient temperature inside the optical module  200  in real time, and transmit the ambient humidity and the ambient temperature to the MCU  310  through the I2C interface. The MCU  310  controls and adjusts the cooling or heating temperature of the TEC  401  in the light-emitting device  400  according to the ambient humidity and ambient temperature, so as to avoid condensation on the surfaces of key optical devices on the TEC  401 . 
     When the optical module operates in an environment of a relatively low humidity, for example, in an air-conditioned data center, the moisture content in the air is low (e.g., the relative humidity is less than or equal to 30%), then in a wide temperature range, such as 25° C. to 35° C., condensation will not occur on the heat exchange surface of the TEC. However, when the optical module operates in some extreme conditions, for example, when the optical module is tested in high temperature and high humidity conditions (e.g., the ambient temperature is greater than 35° C., such as 40° C., 50° C., 60° C., 70° C. or 80° C.; and the relative humidity of the air is greater than or equal to 85%, such as 85%, 90%, 95% or 100%), moisture will enter the non-hermetically sealed cover of the light-emitting device  400 . After a period of time, the relative humidity inside the non-hermetically sealed cover of the light-emitting device  400  will increase significantly and even approach the relative humidity outside the non-hermetically sealed cover of the light-emitting device  400 . If the temperature of the heat exchange surface of the TEC is low, for example, is less than or equal to 50° C., then condensation will occur on both the surface of the TEC and the optical devices installed on the surface, which will block the optical path and affect the normal operation of the optical module. 
     In a case where the effect of the ambient humidity on the temperature of the heat exchange surface of the TEC is not considered when the MCU  310  generates the control signal, the MCU  310  may generate the control signal only according to the ambient temperature in which the laser chip and other optical devices, disposed on the heat exchange surface of the TEC, operate, so as to cool or heat the laser chip and other optical devices. 
     However, if only the ambient temperature in which the laser chip and other optical devices operate is considered, the temperature on the heat exchange surface of the TEC may be lower than the dew point temperature inside the cover of the light-emitting device  400 , which may easily cause condensation on the laser chip and other optical devices. In a case where the effect of the ambient humidity on the temperature of the heat exchange surface of the TEC is considered when the MCU  310  generates the control signal, the MCU  310  may generate the control signal according to both the ambient temperature and the ambient humidity in which the laser chip and other optical devices, disposed on the heat exchange surface of the TEC, operate. As a result, the temperature on the heat exchange surface of the TEC is higher than the dew point temperature corresponding to the ambient temperature and the ambient humidity in which the laser chip and other optical devices, disposed on the heat exchange surface of the TEC, operate, thereby avoiding condensation on the laser chip and other optical devices. 
     In some embodiments, the sensor assembly  330  is configured to obtain the ambient data inside the optical module and send the obtained ambient data to the MCU  310 , the ambient data including the ambient temperature and the ambient humidity. 
     In the non-hermetic sealing method of the light-emitting device  400 , the environment inside the light-emitting device  400  is communicated with the environment inside the optical module. Therefore, the environment inside the optical module may be considered to be equivalent to the environment inside the light-emitting device  400  when obtaining the ambient temperature data and the ambient humidity data. Therefore, the ambient data inside the optical module obtained by the sensor assembly  330  is the ambient data inside the light-emitting device  400 . 
     Since the humidity and temperature changes in real time, the ambient humidity data and the ambient temperature data are also obtained in real time. For example, the ambient data may be obtained periodically at fixed intervals. For example, the sensor assembly  330  obtains the ambient data at intervals of 1 second. 
     The humidity sensor  331  in the sensor assembly  330  is configured to detect the ambient humidity and obtain the ambient humidity data, and send the obtained ambient humidity data to the analog-to-digital converter  333 . The temperature sensor  332  in the sensor assembly  330  is configured to detect the ambient temperature and obtain the ambient temperature data, and send the obtained ambient temperature data to the analog-to-digital converter  333 . The analog-to-digital converter  333  is configured to receive the ambient humidity data and the ambient temperature data, and convert the ambient humidity data and ambient temperature data into digital signals (i.e., ambient humidity and ambient temperature). The analog-to-digital converter  333  is further configured to send the digital signals to the internal processor  334 . The internal processor  334  is configured to convert the digital signals into protocol signals complying with the I2C transmission protocol, and transmit the protocol signals to the MCU  310  through the I2C line. 
     In some embodiments, the sensor assembly  330  is configured to obtain the ambient humidity data but not the ambient temperature data. The ambient temperature data is obtained by the MCU  310  itself. 
     The MCU  310  is further configured to determine the dew point temperature corresponding to the ambient data according to the received ambient data. 
     The MCU  310  is further configured to, after receiving the ambient data sent by the sensor assembly  330 , calculate the dew point temperature corresponding to the ambient data according to the following formula: 
     
       
         
           
             
               
                 
                   
                     1 
                     
                       T 
                       d 
                     
                   
                   = 
                   
                     
                       1 
                       T 
                     
                     - 
                     
                       
                         
                           L 
                           ⁢ 
                           
                             n 
                             ⁡ 
                             
                               ( 
                               
                                 R 
                                 ⁢ 
                                 H 
                               
                               ) 
                             
                           
                         
                         
                           
                             L 
                             / 
                             R 
                           
                           ⁢ 
                           v 
                         
                       
                       . 
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     In the above formula, T is the ambient temperature received by the MCU  310  and is measured on a Kelvin scale (K), and RH is the ambient humidity received by the MCU  310 . For example, the ambient humidity is relative humidity. Ln is the natural logarithm. Td is the dew point temperature when the ambient temperature is T and the ambient humidity is RH, and is measured on the Kelvin scale (K), and L divided by RV is 5423K (L/RV=5423K). 
     The MCU  310  is further configured to calculate the dew point temperature corresponding to the ambient humidity and the ambient temperature through other formulas according to the received ambient humidity and ambient temperature, which is not limited in the present disclosure. Any formula for calculating the dew point temperature by using the ambient temperature and ambient humidity inside the optical module falls within the protection scope of the present disclosure. 
     In some embodiments, the MCU  310  is further configured to obtain the dew point temperature corresponding to the received ambient humidity and ambient temperature in a manner of looking up the dew point temperature in a table. In this manner, the MCU  310  is configured to look up the corresponding dew point temperature in a table by using the ambient humidity and the ambient temperature inside the optical module collected in real time as an index. 
     For example,  FIG. 8  is a diagram showing a relationship between ambient humidity and dew-point temperature of an optical module under different ambient temperatures, in accordance with some embodiments. For example, in a case where the ambient temperature and the ambient humidity obtained by the MCU  310  are 70° C. and 85%, respectively, the corresponding dew point temperature is 67° C.; in a case where the ambient humidity and the ambient humidity obtained by the MCU  310  are 70° C. and 70%, respectively, the corresponding dew point temperature is 63° C. Under the same ambient temperature, the higher the ambient humidity, the higher the corresponding dew point temperature. 
     The MCU  310  is further configured to compare a difference between the received ambient temperature and the calculated dew point temperature with a buffer temperature, and determine whether the difference between the received ambient temperature and the calculated dew point temperature is greater than the buffer temperature. 
     If the difference (T-Td) between the received ambient temperature T and the calculated dew point temperature Td is less than or equal to the buffer temperature Tb, condensation is easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC. In this case, the MCU  310  is configured to control the TEC to adjust the temperature of the heat exchange surface thereof. 
     If the difference (T-Td) between the received ambient temperature T and the calculated dew point temperature Td is greater than the buffer temperature Tb, condensation is not easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC. In this case, the MCU  310  is configured to continue to compare the difference between the received ambient temperature and the calculated dew point temperature with the buffer temperature. 
     For example, the buffer temperature Tb is greater than or equal to 0° C. and less than or equal to 8° C. For example, the buffer temperature is 8° C., 7° C., 6° C., 5° C., 4° C., 3° C., 2° C., 1° C. or 0° C. 
     When the received ambient temperature T and the calculated dew point temperature Td are both measured on a Kelvin scale (K), and the buffer temperature Tb is measured on a Celsius scale (° C.), the buffer temperature Tb can be converted into a Kelvin temperature according to the relationship between the Kelvin scale and the Celsius scale. 
     In a case where the buffer temperature Tb is 0° C., it will not be determined whether the difference (T-Td) between the received ambient temperature T and the calculated dew point temperature Td is greater than the buffer temperature Tb; instead, it will be determined whether the ambient temperature T is greater than the calculated dew point temperature Td. In this case, if the ambient temperature T is equal to the dew point temperature Td, the MCU  310  will not control the TEC to adjust the temperature of the heat exchange surface thereof. This will increase the possibility of condensation on the optical devices on the heat exchange surface of the TEC. However, the present disclosure does not intend to abandon the technical solution that the buffer temperature Tb is 0° C. 
     In a case where the buffer temperature Tb is greater than 0° C., if the ambient temperature T is greater than the dew point temperature Td, the MCU  310  will control the TEC to adjust the temperature of the heat exchange surface thereof. Thus, it may be possible to avoid a situation in which the MCU  310  only controls the TEC to adjust the temperature of the heat exchange surface thereof when the ambient temperature T is equal to the dew point temperature Td, and thus avoid increasing the possibility of condensation on the optical devices on the heat exchange surface of the TEC. 
     It will be noted that, when it is determined whether condensation is easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC, the current temperature of the heat exchange surface of the TEC may be used to replace the ambient temperature received by the MCU  310 . Therefore, in some embodiments, the MCU  310  is further configured to compare a difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature with the buffer temperature, and determine whether the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is greater than the buffer temperature. 
     It will be noted that, the current temperature of the heat exchange surface of the TEC is a target temperature of the heat exchange surface of the TEC indicated by the control signal sent by the MCU  310  to the driving chip  340  of the TEC. 
     If the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is less than or equal to the buffer temperature, condensation is easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC. In this case, the MCU  310  is configured to control the TEC to adjust the temperature of the heat exchange surface thereof. 
     If the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is greater than the buffer temperature, condensation is not easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC. In this case, the MCU  310  is configured to continue to compare the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature with the buffer temperature. 
     It will be noted that, when the MCU  310  compares the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature with the buffer temperature for the first time, since it is impossible to obtain the target temperature of the heat exchange surface of the TEC indicated by the control signal sent by the MCU  310  to the driving chip  340  of the TEC, the ambient temperature detected by the temperature sensor  332  may be used as the current temperature of the heat exchange surface of the TEC. 
     After determining that the difference between the received ambient temperature (or the current temperature of the heat exchange surface of the TEC) and the calculated dew point temperature is less than or equal to the buffer temperature, the MCU  310  is further configured to generate a control signal, and send the generated control signal to the driving chip  340  of the TEC, the control signal indicating the target temperature of the heat exchange surface of the TEC. 
     In some embodiments, the MCU  310  is further configured to determine a compensation temperature according to the received ambient temperature and the calculated dew point temperature. The target temperature of the heat exchange surface of the TEC indicated by the control signal is a sum of the calculated dew point temperature and the compensation temperature. 
     For example, the compensation temperature is in a range of 1° C. to 8° C. For example, the compensation temperature is 8° C., 7° C., 6° C., 5° C., 4° C., 3° C., 2° C. or 1° C. 
     When the received ambient temperature T and the calculated dew point temperature Td are both measured on a Kelvin scale (K), and the compensation temperature is measured on a Celsius scale (° C.), the compensation temperature can be converted into a Kelvin temperature according to the relationship between the Kelvin scale and the Celsius scale. 
     It will be noted that, by setting the compensation temperature to be in a range of 1° C. to 8° C., it may be possible to avoid a situation in which the MCU  310  needs to regenerate the control signal and control the driving chip  340  of the TEC to adjust the temperature of the heat exchange surface of the TEC (which increases the workload of the optical module) every time the ambient temperature inside the optical module changes slightly (e.g., the temperature increases or decreases by 1° C. to 3° C.) when the compensation temperature is too low (e.g., the compensation temperature is less than 1° C.); it may also be possible to avoid a situation in which the adjusted temperature of the heat exchange surface of the TEC becomes too high and affects the operating performance of the laser chip and other optical devices on the heat exchange surface of the TEC when the compensation temperature is too high (e.g., the compensation temperature is greater than 9° C.). 
     In some embodiments, the MCU  310  is further configured to receive a plurality of ambient temperatures (e.g., 2, 3 or 4 ambient temperatures), and arrange the plurality of ambient temperatures according to an order of acquisition time, so as to determine whether the current ambient temperature is in an upward trend or a downward trend. In a case where the arranged plurality of ambient temperatures are getting higher, the MCU  310  is configured to determine that the current ambient temperature is in an upward trend; in a case where the arranged plurality of ambient temperatures are getting lower, the MCU  310  is configured to determine that the current ambient temperature is in a downward trend. 
     When the MCU  310  determines that the current ambient temperature is in an upward trend, the MCU  310  is further configured to determine the compensation temperature to be a value in a range of 1° C. to 4° C.; when the MCU  310  determines that the current ambient temperature is in a downward trend, the MCU  310  is further configured to determine the compensation temperature to be a value in a range of 5° C. to 8° C. 
     In some embodiments, when the current temperature of the heat exchange surface of the TEC is used to replace the ambient temperature received by the MCU  310 , the MCU  310  is further configured to determine the compensation temperature according to the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature, and the target temperature of the heat exchange surface of the TEC indicated by the control signal is a sum of the calculated dew point temperature and the compensation temperature. 
     For example, the compensation temperature is in a range of 1° C. to 8° C. For example, the compensation temperature is 8° C., 7° C., 6° C., 5° C., 4° C., 3° C., 2° C. or 1° C. 
     The practice that the MCU  310  is configured to determine the compensation temperature according to the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is similar to the practice that the MCU  310  is configured to determine the compensation temperature according to the received ambient temperature and the calculated dew point temperature, and details will not be repeated here. 
     The driving chip  340  of the TEC is configured to adjust the temperature of the heat exchange surface of the TEC to the target temperature of the heat exchange surface of the TEC according to the received control signal. 
     The target temperature of the heat exchange surface of the TEC is the sum of the calculated dew point temperature and the compensation temperature. As such, there is an appropriate difference between the current temperature of the heat exchange surface of the TEC and the dew point temperature, which avoids condensation on the optical devices on the heat exchange surface of the TEC. 
     The optical module provided by some embodiments of the present disclosure may be able to keep the temperature of the heat exchange surface of the TEC above the dew point temperature, and avoid condensation on the optical devices on the heat exchange surface of the TEC and the surface thereof. In this way, it may be possible to guarantee the performance of the optical module, improve the reliability and stability of the optical module, and ensure that the optical module can operate normally in extreme conditions. 
       FIG. 9  is a flow diagram of a temperature control method of an optical module, in accordance with some embodiments. Some embodiments of the present disclosure further provide a temperature control method of an optical module, and the optical module may be the optical module as described above. As shown in  FIG. 9 , the temperature control method of the optical module includes steps  01  to  05  (S 01  to S 05 ). 
     In S 01 , the sensor assembly  330  obtains the ambient data inside the optical module, and sends the obtained ambient data to the MCU  310 . The ambient data includes the ambient temperature and ambient humidity. 
     In the non-hermetic sealing method of the light-emitting device  400 , the environment inside the light-emitting device  400  is communicated with the environment inside the optical module. Therefore, the environment inside the optical module may be considered to be equivalent to the environment inside the light-emitting device  400  when obtaining the ambient temperature and ambient humidity. Therefore, the ambient data inside the optical module obtained by the sensor assembly  330  is the ambient data inside the light-emitting device  400 . 
     Since the humidity and temperature changes in real time, the ambient humidity data and the ambient temperature data are also obtained in real time. For example, the ambient data may be obtained periodically at fixed intervals. For example, the sensor assembly  330  obtains the ambient data at intervals of 1 second. 
     The humidity sensor  331  detects the ambient humidity and obtains the ambient humidity data, and sends the obtained ambient humidity data to the analog-to-digital converter  333 . The temperature sensor  332  detects the ambient temperature and obtains the ambient temperature data, and sends the obtained ambient temperature data to the analog-to-digital converter  333 . The analog-to-digital converter  333  receives the ambient humidity data and ambient temperature data, and converts the ambient humidity data and ambient temperature data into the ambient humidity and ambient temperature. Next, the analog-to-digital converter  333  sends the ambient humidity and ambient temperature to the internal processor  334 , and the internal processor  334  converts the ambient humidity and ambient temperature into protocol signals complying with the I2C transmission protocol, and transmits the protocol signals to the MCU  310  through the I2C line. 
     In some embodiments, the sensor assembly  330  only obtains the ambient humidity data inside the optical module, but not the ambient temperature data. The ambient temperature data is obtained by the MCU  310  itself. 
     In S 02 , the MCU  310  determines the dew point temperature corresponding to the ambient data according to the received ambient data. 
     The MCU  310  receives the ambient humidity and ambient temperature, and calculates the dew point temperature corresponding to the ambient humidity and ambient temperature according to the following formula: 
     
       
         
           
             
               
                 
                   
                     
                       1 
                       
                         T 
                         d 
                       
                     
                     = 
                     
                       
                         1 
                         T 
                       
                       - 
                       
                         
                           L 
                           ⁢ 
                           
                             n 
                             ⁡ 
                             
                               ( 
                               
                                 R 
                                 ⁢ 
                                 H 
                               
                               ) 
                             
                           
                         
                         
                           
                             L 
                             / 
                             R 
                           
                           ⁢ 
                           v 
                         
                       
                     
                   
                   . 
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     In the above formula, T is the ambient temperature received by the MCU  310  and is measured on a Kelvin scale (K), and RH is the ambient humidity received by the MCU  310 . For example, the ambient humidity is relative humidity. Ln is the natural logarithm. Td is the dew point temperature when the ambient temperature is T and the ambient humidity is RH, and is measured on the Kelvin scale (K), and L divided by RV is 5423K (L/RV=5423K). 
     According to the ambient humidity and ambient temperature received by the MCU  310 , there may be various formulas according to which the dew point temperature corresponding to the ambient humidity and ambient temperature is calculated, which is not limited in the present disclosure. Any formula for calculating the dew point temperature by using the ambient temperature and ambient humidity inside the optical module falls within the protection scope of the present disclosure. 
     In some embodiments, the MCU  310  may also adopt a manner of looking up the dew point temperature in a table. In this manner, the MCU  310  looks up the dew point temperature corresponding to the received ambient humidity and ambient temperature in a table by using the received ambient humidity and ambient temperature as an index. 
     In S 03 , the MCU  310  compares the difference between the received ambient temperature and the calculated dew point temperature with the buffer temperature, and determines whether the difference between the received ambient temperature and the calculated dew point temperature is greater than the buffer temperature. 
     If the difference (T−Td) between the received ambient temperature T and the calculated dew point temperature Td is less than or equal to the buffer temperature Tb, condensation is easy to occur on the surfaces of the optical devices on the heat exchange surface, and S 04  is performed. 
     If the difference (T−Td) between the received ambient temperature T and the calculated dew point temperature Td is greater than the buffer temperature Tb, condensation is not easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC, and the process returns to S 01 . 
     For example, the buffer temperature Tb is greater than or equal to 0° C. and less than or equal to 8° C. For example, the buffer temperature is 8° C., 7° C., 6° C., 5° C., 4° C., 3° C., 2° C., 1° C. or 0° C. 
     In a case where the buffer temperature Tb is 0° C., it will not be determined whether the difference between the received ambient temperature T and the calculated dew point temperature Td is greater than the buffer temperature Tb; instead, it will be determined whether the ambient temperature T is greater than the calculated dew point temperature Td. In this case, if the ambient temperature T is equal to the dew point temperature Td, the MCU  310  will not control the TEC to adjust the temperature of the heat exchange surface of the TEC. This will increase the possibility of condensation on the optical devices on the heat exchange surface of the TEC. However, the present disclosure does not intend to abandon the technical solution that the buffer temperature Tb is 0° C. 
     In a case where the buffer temperature Tb is greater than 0° C., if the ambient temperature T is greater than the dew point temperature Td, the MCU  310  will control the TEC to adjust the temperature of the heat exchange surface thereof. Thus, it may be possible to avoid a situation in which the MCU  310  only controls the TEC to adjust the temperature of the heat exchange surface thereof when the ambient temperature T is equal to the dew point temperature Td, and thus avoid increasing the possibility of condensation on the optical devices on the heat exchange surface of the TEC. 
     In S 04 , the MCU  310  generates a control signal, and sends the generated control signal to the driving chip  340  of the TEC. The control signal indicates the target temperature of the heat exchange surface of the TEC. 
     After determining that the difference between the received ambient temperature and the calculated dew point temperature is less than or equal to the buffer temperature, the MCU  310  generates the compensation temperature according to the received ambient temperature and the calculated dew point temperature. The target temperature of the heat exchange surface of the TEC indicated by the control signal is a sum of the calculated dew point temperature and the compensation temperature. 
     For example, the compensation temperature is 1° C. to 8° C. For example, the compensation temperature is 8° C., 7° C., 6° C., 5° C., 4° C., 3° C., 2° C. or 1° C. 
     It will be noted that, by setting the compensation temperature to be in a range of 1° C. to 8° C., it may be possible to avoid a situation in which the MCU  310  needs to regenerate the control signal and control the driving chip  340  of the TEC to adjust the temperature of the heat exchange surface of the TEC (which increases the workload of the optical module) every time the ambient temperature inside the optical module changes slightly (e.g., the temperature increases or decreases by 1° C. to 3° C.) when the compensation temperature is too low (e.g., the compensation temperature is less than 1° C.); it may also be possible to avoid a situation in which the adjusted temperature of the heat exchange surface of the TEC becomes too high and affects the operating performance of the laser chip and other optical devices on the heat exchange surface of the TEC when the compensation temperature is too high (e.g., the compensation temperature is greater than 9° C.). 
     In some embodiments, the MCU  310  receives a plurality of ambient temperatures (e.g., 2, 3 or 4 ambient temperatures), and arrange the plurality of ambient temperatures according to the order of acquisition time, so as to determine whether the current ambient temperature is in an upward trend or a downward trend. In a case where the arranged ambient temperatures are getting higher, the MCU  310  determines that the current ambient temperature is in an upward trend; in a case where the arranged ambient temperatures are getting lower, the MCU  310  determines that the current ambient temperature is in a downward trend. 
     When it is determined that the current ambient temperature is in an upward trend, the MCU  310  determines the compensation temperature to be a value in the range of 1° C. to 4° C.; when it is determined that the current ambient temperature is in a downward trend, the MCU  310  determines the compensation temperature to be a value in the range of 5° C. to 8° C. 
     In S 05 , the driving chip  340  of the TEC adjusts the temperature of the heat exchange surface of the TEC to the target temperature of the heat exchange surface of the TEC according to the received control signal. 
     The target temperature of the heat exchange surface of the TEC is the sum of the calculated dew point temperature and the compensation temperature. As such, there is an appropriate difference between the current temperature of the heat exchange surface of the TEC and the dew point temperature, which avoids condensation on the optical devices on the heat exchange surface of the TEC. 
       FIG. 10  is a flow diagram of another temperature control method of an optical module, in accordance with some embodiments. Some embodiments of the present disclosure further provide another temperature control method of an optical module, and the optical module may be the optical module as described above. As shown in  FIG. 10 , the temperature control method of the optical module includes steps S 01 ′ to S 05 ′. 
     In S 01 ′, the sensor assembly  330  obtains the ambient data inside the optical module, and sends the obtained ambient data to the MCU  310 . The ambient data includes the ambient temperature and ambient humidity. 
     In S 02 ′, the MCU  310  determines the dew point temperature corresponding to the ambient data according to the received ambient data. 
     In S 03 ′, the MCU  310  compares the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature with the buffer temperature, and determines whether the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is greater than the buffer temperature. 
     It will be noted that, the current temperature of the heat exchange surface of the TEC is the target temperature of the heat exchange surface of the TEC indicated by the control signal sent by the MCU  310  to the driving chip  340  of the TEC. 
     If the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is less than or equal to the buffer temperature, condensation is easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC, and S 04 ′ is performed. If the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is greater than the buffer temperature, condensation is not easy to occur on the surfaces of the optical devices on the heat exchange surface of the TEC, and the process returns to S 01 ′. 
     It will be noted that, when the MCU  310  compares the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature with the buffer temperature for the first time, since it is impossible to obtain the target temperature of the heat exchange surface of the TEC indicated by the control signal sent by the MCU  310  to the driving chip  340  of the TEC, the ambient temperature detected by the temperature sensor  332  may be used as the current temperature of the heat exchange surface of the TEC. 
     In S 04 ′, the MCU  310  generates a control signal, and sends the generated control signal to the driving chip  340  of the TEC. The control signal indicates the target temperature of the heat exchange surface of the TEC. 
     After determining that the difference between the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is less than or equal to the buffer temperature, the MCU  310  determines the compensation temperature according to the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature. The target temperature of the heat exchange surface of the TEC indicated by the control signal is the sum of the calculated dew point temperature and the compensation temperature. 
     For example, the compensation temperature is in a range of 1° C. to 8° C. For example, the compensation temperature is 8° C., 7° C., 6° C., 5° C., 4° C., 3° C., 2° C. or 1° C. 
     The practice that the MCU  310  determines the compensation temperature according to the current temperature of the heat exchange surface of the TEC and the calculated dew point temperature is similar to the practice that the MCU  310  determines the compensation temperature according to the received ambient temperature and the calculated dew point temperature, and details will not be repeated here. 
     In S 05 ′, the driving chip  340  of the TEC adjusts the temperature of the heat exchange surface of the TEC to the target temperature of the heat exchange surface of the TEC according to the received control signal. 
     The beneficial effects of the temperature control method of the optical module provided by some embodiments of the present disclosure are the same as the beneficial effects of the optical module as described above, and details will not be repeated here. 
     Some embodiments of the present disclosure provide a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium has stored thereon computer program instructions that, when run on a processor (e.g., the MCU  310 ), cause the processor to perform the temperature control method as described above. 
     For example, the non-transitory computer-readable storage medium may include, but is not limited to: a magnetic storage device (e.g., a hard disk, a floppy disk, or a magnetic tape), an optical disk (e.g., a compact disk (CD)), a digital versatile disk (DVD), a smart card and a flash memory device (e.g., an erasable programmable read-only memory (EPROM), a card, a stick or a key drive). The various computer-readable storage media described in the embodiments of the present disclosure may represent one or more devices and/or other machine-readable storage media for storing information. The term “machine-readable storage medium” may include, but is not limited to, wireless channels and various kinds of other media capable of storing, containing, and/or carrying instruction(s) and/or data. 
     The design concepts of the present disclosure are not limited to being applied to a high-speed optical communication module circuit, but can also be applied to other types of optical modules, as well as other products and fields that need to avoid condensation problems. 
     Finally, it will be noted that, the above embodiments are only used to illustrate the technical solutions of the present disclosure, but not to limit the same. Although the present disclosure are described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that the technical solutions described in the foregoing embodiments may still be modified, or some of the technical features may be equivalently replaced, and these modifications or replacements do not deviate essences of corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure. 
     The foregoing descriptions are merely specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art could conceive of changes or replacements within the technical scope of the present disclosure, which shall all be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.