CN113495331A

CN113495331A - Optical module

Info

Publication number: CN113495331A
Application number: CN202010189780.4A
Authority: CN
Inventors: 张强; 赵其圣
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2020-03-18
Filing date: 2020-03-18
Publication date: 2021-10-12

Abstract

The application provides an optical module, which is internally provided with a first laser diode and a second laser diode which are positioned on the same substrate, and an included angle is formed between resonant cavities of the two laser diodes. The first laser diode is driven to emit light by arranging the driving circuit, and the second laser diode is driven to emit light when the first laser diode is controlled to be turned off. The second laser diode and the first laser diode are grown on the same substrate, and when the first laser diode is turned off, the second laser diode can transfer heat generated during the on-state to the first laser diode so as to stabilize the temperature of the first laser diode and reduce the temperature difference caused by the on-state and the off-state of the first laser diode, thereby causing the emission wavelength drift; meanwhile, an included angle is formed between the resonant cavities of the two laser diodes, so that light emitted by the second laser diode can be reduced from entering the coupling lens, and the problem that the turn-off power of the optical module does not reach the standard is avoided.

Description

Optical module

Technical Field

The application relates to the technical field of optical fiber communication, in particular to an optical module.

Background

In the field of optical communications, wavelength division multiplexing is a common bandwidth extension technology in the field of optical communications, and the wavelength division multiplexing technology uses a plurality of lights with different wavelengths to perform data transmission in the same optical fiber, and distinguishes different signal channels according to different optical wavelengths, wherein the ordered data transmission depends on the wavelength stability of optical signals.

In a PON (Passive Optical Network), an Optical Network Unit (ONU) usually performs Optical communication with an Optical Line Terminal (OLT) in a burst light emission manner. Specifically, the optical module in the optical network unit operates in a burst mode, that is, the laser chip in the optical module switches between emitting light and not emitting light. The working mode can cause different temperatures of the laser chip in different states because the laser chip generates heat in the working process. The highest temperature reached by a laser chip when the laser chip works is recorded as Ton; when the laser chip stops working, it does not emit light, so the temperature of the laser chip starts to decrease, and the temperature of the laser chip is recorded as Toff. Generally, a temperature drift coefficient exists between the temperature and the working wavelength of the laser chip, and the coefficient is different from the temperature drift coefficient of different types of laser chips, but is generally between 0.1-0.15 nm/DEG C, namely, the emission wavelength is increased or decreased by one degree per liter, and the emission wavelength can drift by 0.1-0.15 nm. Therefore, each time the laser chip is started to work, the laser chip emits light and generates heat, the temperature of the laser chip is increased from Toff and then is maintained to reach Ton stably, the temperature of the laser chip is changed violently in the process, and the emission wavelength of the laser chip can drift.

As the optical communication bandwidth expands, the wavelengths multiplexed in the optical communication network increase more and more, and the wavelength interval between channels decreases more and more, so that if the temperature difference between Toff and Ton of the laser chip is large to a certain extent, the emission wavelength of the laser chip may drift to an adjacent channel, thereby causing the receiving end to lose the optical signal or receive the wrong optical signal.

Disclosure of Invention

The application provides an optical module to solve the problem that wavelength drift of an optical signal emitted by an existing optical module in a burst mode is serious.

The optical module provided by the embodiment of the application mainly comprises:

a circuit board;

the laser chip is electrically connected with the circuit board and comprises a first laser diode and a second laser diode which are positioned on the same substrate, and a resonant cavity of the second laser diode is arranged in a non-parallel mode with a resonant cavity of the first laser diode;

the driving circuit is arranged on the circuit board, is electrically connected with the first laser diode and the second laser diode respectively through the circuit board and is used for driving the first laser diode to emit light; and the second laser diode is driven to emit light when the first laser diode is controlled to be turned off;

and the coupling lens is arranged on the light emitting side of the first laser diode and used for collimating the light emitted by the first laser diode.

The optical module of the embodiment of the application is internally provided with a first laser diode and a second laser diode which are positioned on the same substrate, and a driving circuit is arranged to be electrically connected with the first laser diode and the second laser diode respectively. The first laser diode is driven to emit light by arranging the driving circuit, and the second laser diode is driven to emit light when the first laser diode is stopped to emit light. Thus, when the first laser diode is turned off, the second laser diode is turned on, and the second laser diode and the first laser diode are grown on one laser chip, at the moment, the second laser diode can transfer heat generated in the turning-on process to the first laser diode so as to stabilize the temperature of the first laser diode and reduce the temperature difference between the turning-on and turning-off of the first laser diode and the emitted emission wavelength drift caused by the temperature difference; meanwhile, an included angle is formed between the resonant cavity of the second laser diode and the resonant cavity of the first laser diode, so that light emitted by the second laser diode can be prevented from entering the coupling lens, and the problem that the turn-off power of the whole optical module does not reach the standard during the turn-off period of the first laser diode is solved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without any inventive exercise.

Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal;

FIG. 2 is a schematic diagram of an optical network unit;

fig. 3 is a schematic structural diagram of an optical module provided in this embodiment;

fig. 4 is an exploded schematic structural diagram of an optical module provided in this embodiment;

fig. 5 is a schematic partial structure diagram of a first optical module provided in this embodiment;

fig. 6 is a schematic structural diagram of a laser chip provided in this embodiment;

fig. 7 is a schematic diagram of a positional relationship between a laser chip and a coupling lens provided in this embodiment;

fig. 8 is a timing diagram of a burst signal provided in this embodiment;

fig. 9 is a schematic partial structure diagram of a second optical module provided in this embodiment;

fig. 10 is a partial structural schematic diagram of a third optical module provided in this embodiment;

fig. 11 is a partial structural schematic diagram of a fourth optical module provided in this embodiment;

fig. 12 is a schematic partial structural diagram of a fifth optical module provided in this embodiment;

fig. 13 is a partial structural schematic diagram of a sixth optical module provided in this embodiment.

Detailed Description

The technical solutions in the embodiments will be described clearly and completely with reference to the drawings in the embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

One of the core elements of fiber optic communications is the conversion of optical to electrical signals. The optical fiber communication uses the optical signal carrying information to transmit in the optical fiber/optical waveguide, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of the light in the optical fiber. The information processing devices such as computers use electrical signals, which require the interconversion between electrical signals and optical signals during the signal transmission process.

The optical module realizes the photoelectric conversion function in the technical field of optical fiber communication, and the interconversion of optical signals and electric signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on a circuit board, main electrical connections comprise power supply, I2C signals, data signal transmission, grounding and the like, the electrical connection mode realized by the golden finger becomes a standard mode of the optical module industry, and on the basis, the circuit board is a necessary technical characteristic in most optical modules.

Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes an optical network unit 100, an optical module 200, an optical fiber 101, and a network cable 103;

one end of the optical fiber is connected with the far-end server, one end of the network cable is connected with the local information processing equipment, and the connection between the local information processing equipment and the far-end server is completed by the connection between the optical fiber and the network cable; and the connection between the optical fiber and the network cable is completed by an optical network unit with an optical module.

An optical port of the optical module 200 is connected with the optical fiber 101 and establishes bidirectional optical signal connection with the optical fiber; the electrical port of the optical module 200 is accessed into the optical network unit 100, and establishes bidirectional electrical signal connection with the optical network unit; the optical module realizes the mutual conversion of optical signals and electric signals, thereby realizing the connection between the optical fiber and the optical network unit; specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input to the optical network unit 100, and the electrical signal from the optical network unit 100 is converted into an optical signal by the optical module and input to the optical fiber. The optical module 200 is a tool for realizing the mutual conversion of the photoelectric signals, and has no function of processing data, and information is not changed in the photoelectric conversion process.

The optical network unit is provided with an optical module interface 102, which is used for accessing an optical module and establishing bidirectional electric signal connection with the optical module; the optical network unit is provided with a network cable interface 104 for accessing a network cable and establishing bidirectional electric signal connection with the network cable; the optical module is connected with the network cable through the optical network unit, specifically, the optical network unit transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network unit is used as an upper computer of the optical module to monitor the work of the optical module.

At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device through the optical fiber, the optical module, the optical network unit and the network cable.

Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network unit is an upper computer of the optical module, provides data signals for the optical module, and receives the data signals from the optical module, and the common upper computer of the optical module also comprises an optical line terminal and the like.

Fig. 2 is a schematic diagram of an optical network unit structure. As shown in fig. 2, the optical network unit 100 includes a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a convex structure such as a fin for increasing a heat radiation area.

The optical module 200 is inserted into an optical network unit, specifically, an electrical port of the optical module is inserted into an electrical connector in the cage 106, and an optical port of the optical module is connected with the optical fiber 101.

The cage 106 is positioned on the circuit board, enclosing the electrical connectors on the circuit board in the cage; the optical module is inserted into the cage, the cage fixes the optical module, and heat generated by the optical module is conducted to the cage through the optical module housing and finally diffused through the heat sink 107 on the cage.

Fig. 3 is a schematic structural diagram of an optical module 200 according to an embodiment of the present disclosure, and fig. 4 is an exploded structural diagram of the optical module 200 according to the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in an embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking handle 203, a circuit board 204, a light emitting module 205, and a light receiving module 206.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body, and specifically, the lower shell comprises a main plate and two side plates which are positioned at two sides of the main plate and are perpendicular to the main plate; the upper shell comprises a cover plate, and the cover plate covers two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned at two sides of the cover plate and are perpendicular to the cover plate, and the two side walls are combined with the two side plates to realize that the upper shell covers the lower shell.

The two openings can be two ends (208, 209) in the same direction, or two openings in different directions; one opening is an electric port 208, and a gold finger of the circuit board extends out of the electric port 208 and is inserted into an upper computer such as an optical network unit; the other opening is an optical port 209 for external optical fiber access to connect the optical transmitting assembly 205 and the optical receiving assembly 206 inside the optical module; optoelectronic devices such as circuit board 204, light emitting assembly 205 and light receiving assembly 206 are located in the package cavity.

The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 204, the light emitting assembly 205, the light receiving assembly 206 and other devices can be conveniently installed in the shell, and the outermost packaging protection shell of the optical module is formed by the upper shell and the lower shell; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the shell of the optical module cannot be made into an integrated structure, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation structure and the electromagnetic shielding structure cannot be installed, and the production automation is not facilitated.

The unlocking handle 203 is located on the outer wall of the wrapping cavity/lower shell 202 and used for realizing the fixed connection between the optical module and the upper computer or releasing the fixed connection between the optical module and the upper computer.

The unlocking handle 203 is provided with a clamping structure matched with the upper computer cage; the tail end of the unlocking handle is pulled to enable the unlocking handle to move relatively on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer through a clamping structure of the unlocking handle; by pulling the unlocking handle, the clamping structure of the unlocking handle moves along with the unlocking handle, so that the connection relation between the clamping structure and the upper computer is changed, the clamping relation between the optical module and the upper computer is relieved, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 204 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as the microprocessor MCU2045, the laser driver chip, the limiting amplifier, the clock data recovery CDR, the power management chip, and the data processing chip DSP).

The circuit board 204 connects the electrical devices in the optical module together according to circuit design through circuit wiring to realize electrical functions such as power supply, electrical signal transmission, grounding and the like.

The circuit board 204 is generally a rigid circuit board, which can also realize a bearing effect due to its relatively hard material, for example, the rigid circuit board can stably bear a chip; the rigid circuit board may also provide a smooth load bearing when the light emitting assembly 205 and the light receiving assembly 206 are located on the circuit board; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/golden finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.

A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver device through the flexible circuit board.

The optical transmitter 205 and the optical receiver 206 are respectively used for transmitting and receiving optical signals. The optical transmit module 206 in this embodiment is a coaxial TO package, physically separated from the circuit board, and electrically connected through a flex board; the light receiving element 206 is also a coaxial TO package, physically separated from the circuit board and electrically connected by a flex board. In another common implementation, may be disposed on a surface of the circuit board 204; in addition, the light emitting module 205 and the light receiving module 206 may be combined together to form an integrated light transmitting and receiving structure.

Further, the gold finger on the surface of the circuit board 204 has I2C pins, and the upper computer and the optical module can transmit information through I2C pins by using an I2C protocol. For signal emission of the optical module, a burst signal from the upper computer enters the laser driving chip Driver through input of a golden finger on the surface of the circuit board 204, and the laser driving chip Driver performs amplitude adjustment on the burst signal and then outputs the burst signal to the light emitting assembly 205 so as to drive a laser chip in the light emitting assembly 205 to emit light with a preset wavelength. However, in the burst mode, the continuous turning on and off of the laser chip in the optical transmitting element 205 may cause the light emitting wavelength to change due to the temperature change of the chip, and as the optical communication bandwidth expands, the multiplexed wavelength in the optical communication network increases, the interval between the wavelengths decreases, and the speed of the optical signal increases, so that the actual wavelength of the light emitted by the laser chip is mixed with the preset communication channel, and the receiving end loses the optical signal or receives the optical signal with an error.

In view of the above problems, the present embodiment designs a new optical module scheme. Fig. 5 is a partial structural schematic diagram of a first optical module provided in this embodiment. In actual products, there are various packaging methods adopted in an optical module, such as TO package, COB package, BOX package, silicon-based optical chip package, and the like, and a specific structure of a specific package is adaptively changed, but the essential principle of the specific package is as shown in fig. 5. The driving circuit 10 is provided in the optical module in the present embodiment, and the laser chip 20 in the light emitting module is additionally provided to include a first laser diode 21 and a second laser diode 22.

Fig. 6 is a schematic structural diagram of a laser chip provided in this embodiment. As shown in fig. 6, two active regions Wa and Wb are simultaneously disposed on a substrate 23 of a laser chip 20, an isolation trench 24 is disposed between the active regions Wa and Wb, and the laser chip is divided into two light emitting units by the isolation trench 24, in which the two independent light emitting units are respectively a first laser diode 21 and a second laser diode 22. In addition, the resonant cavity of the first laser diode 21 and the resonant cavity of the second laser diode 22 are disposed in a non-parallel manner, that is, they have a certain included angle, so in the cross-sectional view of the laser chip in fig. 6, the widths of the active regions of the first laser diode 21 and the second laser diode 22 are different.

The driving circuit 10 is disposed on the circuit board 204 and electrically connected to the anodes of the first laser diode 21 and the second laser diode 22 through traces on the circuit board 204. The cathodes of the first laser diode 21 and the second laser diode 22 are attached to a TEC (thermoelectric cooler) and grounded, but may be directly grounded.

A double-pole double-throw switch is arranged in the driving circuit 10, the double-pole double-throw switch is controlled by burst signals, one end of the double-pole double-throw switch is respectively electrically connected with the anodes of the first laser diode 21 and the second laser diode 22, the other end of the double-pole double-throw switch is respectively movably connected with the contacts A, A ' and B, B ', the contacts a and B ' are grounded, the contacts a ' and B ' are connected with a current source, the contacts a and B can be conducted with the first laser diode 21, and the contacts a ' and B ' can be conducted with the second laser diode 22.

Fig. 8 is a timing diagram of a burst signal provided in this embodiment. As shown in fig. 8, the burst signal is a rectangular wave signal whose voltage varies with time. At time t1, the low level is changed to the high level; at time t2, the high level is changed to the low level; at time t3, change from low to high, and so on. The burst signal is generally generated by an upper computer, and the time for holding the high level or the low level is set by the actual lighting requirement. The present embodiment sets that when the burst signal is at the first level, the driving circuit drives 10 the first laser diode 21 to operate; when the burst signal is at the second level, the first laser diode 21 is stopped to be driven and the second laser diode 22 is driven to be operated. The burst signal is a signal in which a first level and a second level are changed with each other, and is embodied as a signal in which high and low levels are changed. Specifically, when the optical signal needs to be transmitted, a high level signal may be provided to the driving circuit 10; when the optical signal does not need to be transmitted, a low level signal is supplied to the drive circuit 10. Of course, when the optical signal needs to be transmitted, a low level signal may be provided to the driving circuit 10; when the optical signal does not need to be transmitted, a high level signal is supplied to the drive circuit 10.

Based on the timing variation of the burst signal. When the burst signal is at the first level, the enabling double-pole double-throw switch is conducted with B and B', at this time, the anode of the first laser diode 21 is connected with the bias current to emit light, and the anode of the second laser diode 22 is grounded and can not emit light. When the burst signal is at the second level, when the enable double-pole double-throw switch is conducted with a and a', the anode of the first laser diode 21 is grounded, the anode of the second laser diode 22 is connected with a bias current, at this time, the second laser diode 22 can obtain current and normally emit light, and the first laser diode 21 does not emit light because no current is obtained; when the coupling laser emits light, the first laser diode 21 is selected as a working diode, light emitted by the first laser diode 21 is aligned to the coupling lens 30, and then the light emitted by the coupling lens is coupled into the optical fiber, the second laser diode 22 is a heating diode, and an included angle is formed between the resonant cavity of the second laser diode 22 and the resonant cavity of the first laser diode 21, so that the light emitted by the second laser diode 22 can be effectively reduced from being coupled into the optical fiber through the coupling lens 30.

Fig. 7 is a schematic diagram of a positional relationship between the laser chip and the coupling lens provided in this embodiment. As shown in fig. 7, in order to prevent the light emitted from the second laser diode 22 from being coupled into the optical fiber through the coupling lens 30 as much as possible, in the present embodiment, the light emitting point of the first laser diode 21 is located near the focal point F of the coupling lens 30, and the included angle θ between the resonant cavity of the second laser diode 22 and the resonant cavity of the first laser diode 21 is larger than the included angle μ between the central axis of the coupling lens 30 and the maximum angle light, where the maximum incident angle light μ is defined as the light parallel to the connection line between the focal point F of the coupling lens 30 and the edge of the coupling lens 30. In addition, a light absorbing member may be disposed in the light emitting direction of the second laser diode 22TO absorb the light emitted from the second laser diode 22, wherein the light absorbing member may be disposed on the light emitting cavity surface of the second laser diode 22, or attached TO an inner wall for packaging the first laser diode 21 and the second laser diode 22TO tubes, or the like.

In the embodiment, two laser diodes are designed on a chip level, and the two laser diodes have very close thermal efficiency when working by combining the strong consistency of the existing chip manufacturing process, and grow on the same substrate, the heat exchange efficiency of the two laser diodes is very high, and by configuring the driving circuit, only one of the two laser diodes works at the same time no matter the first laser diode 21 works or the second laser diode 22 works, so that the heat change generated by the whole laser chip is very small, the wavelength change is very small, and the harsh wavelength division multiplexing technical requirement can be met. Meanwhile, an included angle is formed between the resonant cavity of the second laser diode 22 and the resonant cavity of the first laser diode 21, so that light emitted by the second laser diode 22 can be prevented from entering the coupling lens, and the problem that the turn-off power of the whole optical module does not reach the standard during the turn-off period of the first laser diode 21 is solved.

Further, the driving circuit 10 in the present embodiment may also adopt other circuit structures, and specific embodiments will be given below.

Fig. 9 is a partial structural schematic diagram of a second optical module provided in this embodiment. As shown in fig. 9, in the optical module provided in this embodiment, the driving circuit 10 includes a first driving circuit 11 and a second driving circuit 12, the first driving circuit 11 is connected to the first laser diode 21, and the second driving circuit 12 is connected to the second laser diode 22, where the first driving circuit 11 is configured to enable the first laser diode 21 to emit light with an operating wavelength when the received burst signal is at a first level value; for stopping the first laser diode 21 from emitting light, i.e. turning it off, when the received burst signal is at the second level value; and a second driving circuit 12 for making the second laser diode 22 emit light when receiving the burst signal at the second level value.

Specifically, the first driving circuit 11 may employ an existing laser driving chip. For example, in one embodiment, the anode of the first laser diode 21 is connected to a current source capable of outputting a predetermined current signal, and the cathode of the first laser diode 21 is connected to the first driving circuit 11. At this time, when the received burst signal is at the first level, the first driving circuit 11 sets the port connected to the first laser diode 21 to the low level, so that a voltage difference exists between both ends of the first laser diode 21, and the first laser diode 21 is turned on to emit light of the operating wavelength. Further, when the received burst signal is at the second level, the first driving circuit 11 puts the port connected to the first laser diode 21 at a high level, for example, puts the port connected to the first laser diode at a voltage having the same value as that of the current source output port, and at this time, there is no voltage difference between the two ends of the first laser diode 21, and the first laser diode 21 is turned off.

Further, the second driving circuit 12 may adopt an existing laser driving chip, or may adopt other circuit structures, and specific embodiments will be given below for describing the circuit structure of the second driving circuit 12 in detail, which will not be described herein again.

Fig. 10 is a partial structural schematic diagram of a third optical module provided in this embodiment. As shown in fig. 10, in the optical module provided in this embodiment based on the second optical module, the second driving circuit 12 includes a first electric switch 121, a first MOS transistor 122, and a first operational amplifier 123.

The input end of the first operational amplifier 123 is connected to the MCU of the optical module, the output end of the first operational amplifier 123 is connected to the gate G of the first MOS transistor 122, the drain D of the first MOS transistor 122 is connected to the cathode of the second laser diode, and the source S of the first MOS transistor 122 is connected to the first end of the first electrical switch 121. The second terminal of the first electrical switch 121 may be connected to ground through a resistor. Meanwhile, the first electric switch 121 is closed when the received burst signal is at the second level value, so as to turn on the second laser diode 22.

In addition, the specific structure of the first operational amplifier 123 can be referred to the description in the prior art, and is not described herein again. Further, the first operational amplifier 123 may be an operational amplifier with a fixed amplification factor or an operational amplifier with an adjustable amplification factor, and when the first operational amplifier 123 is an operational amplifier with an adjustable amplification factor, the amplification factor of the first operational amplifier 123 may be adjusted according to actual needs, for example, the amplification factor of the first operational amplifier 123 is adjusted to 1 to reduce the temperature drift of the first laser diode 21 to the maximum extent.

Further, an input end of the first operational amplifier 123 is connected to an MCU of the optical module, and the MCU is configured to provide an input voltage to the first operational amplifier 123. In particular, the MCU may determine a particular value of the input voltage provided to the first operational amplifier 123 based on feedback data (e.g., the feedback data may include a bias current or a wavelength of light emitted by the first laser diode 21) to control the magnitude of the current flowing through the second laser diode 22. For example, in one embodiment, the specific value of the input voltage provided to the first operational amplifier 123 may be determined according to the current flowing through the first laser diode 21 when the first laser diode 21 emits the optical signal, so as to control the current flowing through the second laser diode 22, thereby reducing the temperature difference from the first laser diode 21 to the turn-on process during the turn-off process to 0. For example, in one embodiment, when the first laser diode 21 is turned on, the current flowing through the first laser diode 21 is i 1. Meanwhile, when the first laser diode 21 is conductive, the second laser diode 22 is nonconductive. At this time, in order to reduce the temperature drift of the first laser diode 21, i12 × r1 × 6.25 × i22 × r2 × 118.75 (where i2 is the current flowing through the second laser diode 22 when the second laser diode 22 is turned on, r1 is the internal resistance of the first laser diode 21, r2 is the internal resistance of the second laser diode 22, 6.25us is the time when the first laser diode 21 is turned on in a burst signal cycle, and 118.75us is the time when the first laser diode 21 is turned off in a burst signal cycle) may be set. Thus, by i1, i2 can be calculated, and further, the specific value of the input voltage provided by the MCU to the first operational amplifier 123 can be determined according to i2 and the current amplification factor of the first operational amplifier 123 (for example, the specific value of the input voltage provided by the MCU to the first operational amplifier 123 is determined to be aV). Thus, when the MCU supplies the input voltage aV to the first operational amplifier 123 and the second laser diode 22 is turned on, the current flowing through the second laser diode 22 is i 2.

In the optical module provided by this embodiment, the second driving circuit is set to be a circuit including the first operational amplifier, the first MOS transistor and the first electric switch, so that when the second laser diode is controlled to be turned on by the MCU, the current flowing through the second laser diode controls the heat emitted by the second laser diode, and further the temperature difference from the first laser diode to the turn-on process in the turn-off process is reduced to 0, so as to reduce the temperature drift of the optical signal emitted by the first laser diode due to the temperature drift of the first laser diode.

Fig. 11 is a partial structural schematic diagram of a fourth optical module provided in this embodiment. As shown in fig. 11, in the optical module provided in this embodiment, the anode of the first laser diode 21 is connected to the current source, and the cathode of the first laser diode 21 is connected to the first driving circuit 11; the anode of the second laser diode 22 is connected with the second driving circuit 12, and the cathode of the second laser diode 22 is grounded; the second driving circuit 12 is configured to output a current to the second laser diode 22 when receiving the burst signal at the second level value, so as to turn on the second laser diode 22.

The anode of the first laser diode 21 may be connected via a resistor to a current source, which may be a 3.3V current source. In addition, the first driving circuit 11 may adopt an existing laser driving chip, and in this case, only one bias current port of the driving chip needs to be connected to the cathode of the first laser diode 21.

In this embodiment, the magnitude of the current output by the second driving circuit 12 may be controlled by a controller in the optical module, where the controller may specifically be an MCU originally integrated in the optical module, and the controller may also be an FPGA or a CPU. For example, in an embodiment, the magnitude of the current output by the second driving circuit 12 may be adjusted according to the current flowing through the first laser diode 21 when the first laser diode 21 emits light, so as to adjust the amount of heat emitted when the second laser diode 22 is turned on, thereby reducing the temperature difference from the turn-off process to the turn-on process of the first laser diode 21 to 0. For a specific implementation principle of adjusting the current output by the second driving circuit 12 according to the current flowing through the first laser diode 21 when the first laser diode 21 is turned on, reference may be made to the description of the foregoing embodiment, and details are not described here.

Fig. 12 is a partial structural schematic diagram of a fifth optical module provided in this embodiment. As shown in fig. 12, in the optical module provided in this embodiment, the second driving circuit 12 includes a second operational amplifier 124, a second MOS transistor 125, and a second electrical switch 126.

The input end of the second operational amplifier 124 is connected to the MCU of the optical module, the output end of the second operational amplifier 124 is connected to the gate G of the second MOS transistor 125, the source S of the second MOS transistor 125 is connected to the current source, the drain D of the second MOS transistor 125 is connected to the first end of the second electrical switch 126, the second end of the second electrical switch 126 is connected to the anode of the second laser diode 22, and the cathode of the second laser diode 22 is grounded.

The second electrical switch 126 is configured to connect the second MOS transistor 125 to the second laser diode 22 when the received burst signal is at the second level value.

In addition, the second operational amplifier 124 may be an operational amplifier with a fixed amplification factor or an operational amplifier with an adjustable amplification factor, and when the second operational amplifier 124 is an operational amplifier with an adjustable amplification factor, the amplification factor of the second operational amplifier 124 may be adjusted according to actual needs, for example, the amplification factor of the second operational amplifier 124 is adjusted to 2 in order to control the heat emitted by the second laser diode 22 when the second laser diode 22 is turned on. Further, an input end of the second operational amplifier 124 is connected to an MCU of the optical module, and the MCU is configured to provide an input voltage to the second operational amplifier 124. Specifically, the MCU may control the current flowing through the second laser diode 22 according to the feedback data (for example, the feedback data may be the bias current or the wavelength of light emitted by the first laser diode 21), so as to reduce the temperature difference from the first laser diode 21 to the on-state during the off-state to 0. To reduce the wavelength shift of the optical signal emitted by the first laser diode 21 due to temperature drift thereof.

Optionally, in one possible implementation of the present application, the second electrical switch 126 is a single-pole single-throw electrical switch; and a second electric switch 126, configured to close when the received burst signal is at the second level value, so that the second MOS transistor 125 outputs a current to the second laser diode 22. Further, in another possible implementation of the present application, the second electrical switch 126 is a switch.

Fig. 13 is a partial structural schematic diagram of a sixth optical module provided in this embodiment. As shown in fig. 13, the second driving circuit 12 further includes a first resistor 127, a third terminal of the second electrical switch 126 is connected to a first terminal of the first resistor 127, and a second terminal of the first resistor 127 is grounded; the second electrical switch 126 is used for connecting the second MOS transistor 125 with the first resistor 127 when the received burst signal is at the first level value.

Specifically, in the optical module provided in this embodiment, the second electrical switch 126 is set as a switch. Thus, when the burst signal is received at the first level, the first terminal of the second electrical switch 126 is connected to the third terminal, and at this time, the second laser diode 22 is not turned on and the first resistor 127 is turned on, and when the burst signal is received at the second level, the first terminal of the second electrical switch 126 is connected to the second terminal, and at this time, the second laser diode 22 is turned on. In the present embodiment, although the first resistor 127 is turned on when the first laser diode 21 is turned on, the first resistor 127 is not thermally coupled to the first laser diode 21. Therefore, the first resistor 127 generates heat when the first laser diode 21 is turned on, but does not transmit the generated heat to the first laser diode 21.

In the optical module provided by this embodiment, the second driving circuit is configured as a circuit including the second operational amplifier, the second MOS transistor and the second electric switch, so that when the second laser diode is turned on, the current flowing through the second laser diode can be controlled by controlling the input voltage or the amplification factor of the second operational amplifier, so as to reduce the temperature drift of the first laser diode to the maximum extent and reduce the wavelength drift of the optical signal emitted by the first laser diode due to the temperature drift of the first laser diode.

It should be noted that the optical module provided in this embodiment is not only applicable to the form in which the optical transmitter module and the optical receiver module are separately packaged, but also applicable to the form in which the optical transmitter module and the optical receiver module are packaged together to form an optical transceiver sub-module, and an optical transceiver chip is mounted on a circuit board, and for any package form, the relevant devices for transmitting optical signals are referred to as optical transmitter modules in this embodiment, and the relevant devices for receiving optical signals are referred to as optical receiver modules in this embodiment. The optical module may be an optical module in an OLT or an ONU, but is not limited thereto.

Finally, it should be noted that: the embodiment is described in a progressive manner, and different parts can be mutually referred; in addition, 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 will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A light module, comprising:

a circuit board;

2. The optical module according to claim 1, wherein a light-absorbing member is provided in a light-emitting direction of the second laser diode.

3. The optical module according to claim 1 or 2, wherein the light exit point of the first laser diode is located near the focal point of the coupling lens;

the included angle between the resonant cavity of the second laser diode and the resonant cavity of the first laser diode is larger than the included angle between the central axis of the coupling lens and the maximum angle ray;

the maximum incidence angle light ray is a light ray parallel to a line connecting the focal point and the edge of the coupling lens.

4. The light module of claim 1, wherein the drive circuit comprises a toggle switch, wherein:

the first end of the change-over switch is connected with a current source, the second end of the change-over switch is connected with the anode of the first laser diode, and the third end of the change-over switch is connected with the anode of the second laser diode;

the change-over switch is used for connecting the current source with the first laser diode when the received burst signal is at a first level value so as to enable the first laser diode to emit light; and the current source is used for connecting the current source with the second laser diode when the received burst signal is at a second level value, so that the first laser diode is turned off and the second laser diode emits light.

5. The light module of claim 1, wherein the drive circuit comprises a first drive circuit and a second drive circuit, wherein:

the first driving circuit is connected with the first laser diode and used for enabling the first laser diode to emit light when the received burst signal is at a first level value; and stopping the first laser diode from emitting light when the received burst signal is at a second level value;

and the second driving circuit is connected with the second laser diode and used for enabling the second laser diode to emit light when the received burst signal is at a second level value.

6. A light module as claimed in claim 5, characterized in that the second drive circuit comprises a first electrical switch, wherein:

the anode of the first laser diode and the anode of the second laser diode are respectively connected with a current source, and the cathode of the first laser diode is connected with the first driving circuit;

the cathode of the second laser diode is connected with the first end of the first electric switch, and the second end of the first electric switch is grounded;

and the first electric switch is closed when the received burst signal is at a second level value, so that the second laser diode emits light.

7. The optical module of claim 6, wherein the second driving circuit further comprises a first operational amplifier and a first MOS transistor, wherein:

the input end of the first operational amplifier is connected with the MCU of the optical module, the output end of the first operational amplifier is connected with the grid electrode of the first MOS tube, the drain electrode of the first MOS tube is connected with the cathode of the second laser diode, and the source electrode of the first MOS tube is connected with the first end of the first electric switch.

8. The optical module according to claim 5, wherein an anode of the second laser diode is connected to the second drive circuit, and a cathode of the second laser diode is grounded;

and the second driving circuit is used for outputting current to the second laser diode when the received burst signal is at a second level value so as to enable the second laser diode to emit light.

9. The optical module of claim 8, wherein the second driving circuit comprises a current source, a second operational amplifier, a second MOS transistor, and a second electrical switch, wherein:

the input end of the second operational amplifier is connected with the MCU of the optical module, the output end of the second operational amplifier is connected with the grid electrode of the second MOS tube, the source electrode of the second MOS tube is connected with the output end of the current source, the drain electrode of the second MOS tube is connected with the first end of the second electric switch, the second end of the second electric switch is connected with the anode of the second laser diode, and the cathode of the second laser diode is grounded;

and the second electric switch is used for connecting the second MOS tube with the second laser diode when the received burst signal is at a second level value.

10. The light module of claim 9, wherein the second electrical switch is a switch, the second drive circuit further comprising a first resistor, wherein:

the third end of the second electric switch is connected with the first end of the first resistor, and the second end of the first resistor is grounded;

and the second electric switch is used for connecting the second MOS tube with the first resistor when the received burst signal is at a first level value.