CN212649470U - Optical module - Google Patents

Abstract

An optical module includes a circuit board. The circuit board is provided with a laser driving chip, a laser chip, a first switch, a second switch and a third switch. And the first end and the second end of the laser driving chip are respectively connected with the first ends of the first switch and the second switch. The second end of the first switch is connected with the power supply, and the third end of the first switch is connected with the golden finger; the second end of the second switch is connected with the second end of the laser chip, and the third end of the second switch is connected with the golden finger; and the second end of the third switch is electrically connected with the second end of the laser chip, and the third end of the third switch is connected with the golden finger. The burst control signal sent by the upper computer controls the burst opening or burst closing of the first switch, the second switch and the third switch, the burst opening or burst closing of the first switch, the second switch and the third switch controls the modulation current flowing through the first switch and the second switch to be burst opened or closed, and also controls the bias current flowing through the third switch to be burst opened or closed, so that the burst opening or burst closing of the light emitting device is controlled, and the optical power loss is reduced.

Description

Optical module

Technical Field

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

Background

In a PON (Passive optical network) system, a TDMA (Time division multiple access) technology is used to transmit an uplink signal of an ONU (optical network unit) optical module, and therefore, an optical transmitter of the ONU optical module needs to implement burst transmission or burst shutdown. However, the conventional laser driving chip in the light emitting device is in a continuous mode, so that the light emitting device cannot realize burst emission or burst turn-off.

In order to realize burst emission or burst turn-off of the light emitting device, a bias circuit is generally provided outside the light emitting device. The bias circuit provides bias current for the laser in the light emitting device to realize burst on or burst off of the laser, namely burst emission or burst off of the light emitting device.

When burst emission or burst cut-off of the light emitting device is performed, the burst cut-off or burst cut-on bias circuit is used for realizing the burst cut-off or burst cut-on bias circuit. However, since the conventional laser driving chip is always in a working state, the driving current generated by the laser driving chip is always loaded on the laser, which results in a partial optical power loss.

SUMMERY OF THE UTILITY MODEL

The application provides an optical module, which reduces optical power loss.

A light module, comprising:

a circuit board is provided with a plurality of circuit boards,

a light emitting device including a laser chip for emitting a light signal;

the first end of the laser chip is electrically connected with a power supply and is used for controlling the emitted optical signal according to the bias current and the modulation current;

the circuit board is provided with a laser driving chip, a first switch, a second switch and a third switch;

the first end of the laser driving chip is electrically connected with the first end of the first switch, the second end of the laser driving chip is electrically connected with the first end of the second switch, and the third end of the laser driving chip is grounded and used for controlling bias current and modulation current flowing through the laser chip;

the second end of the first switch is electrically connected with the power supply, and the third end of the first switch is electrically connected with the golden finger and is used for controlling the burst opening or the burst closing of the modulation current flowing through the first switch according to the burst control signal;

the second end of the second switch is electrically connected with the second end of the laser chip, and the third end of the second switch is electrically connected with the golden finger and is used for controlling the burst on or burst off of the modulation current flowing through the second switch according to the burst control signal;

and the second end of the third switch is electrically connected with the second end of the laser chip, and the third end of the third switch is electrically connected with the golden finger and is used for controlling the burst opening or the burst closing of the bias current flowing through the third switch according to the burst control signal.

Has the advantages that: the application provides a light module, which comprises a circuit board and a light emitting device for emitting light signals. The circuit board is provided with a laser driving chip, a first switch, a second switch and a third switch. The light emitting device includes a laser chip. The laser chip is used for controlling the emitted light signal according to the bias current and the modulation current. And the first end of the laser driving chip is electrically connected with the first end of the first switch, the second end of the laser driving chip is electrically connected with the first end of the second switch, and the third end of the laser driving chip is grounded and used for controlling the bias current and the modulation current flowing through the laser chip. The second end of the first switch is electrically connected with the power supply, and the third end of the first switch is electrically connected with the golden finger and is used for controlling the burst opening or the burst closing of the modulation current flowing through the first switch according to the burst control signal; the second end of the second switch is electrically connected with the second end of the laser chip, and the third end of the second switch is electrically connected with the golden finger and is used for controlling the burst on or burst off of the modulation current flowing through the second switch according to the burst control signal; and the second end of the third switch is electrically connected with the second end of the laser chip, and the third end of the third switch is electrically connected with the golden finger and is used for controlling the burst opening or burst closing of the bias current flowing through the third switch according to the burst control signal. The laser driving chip controls bias current and modulation current flowing through the laser chip according to signals sent by the upper computer, and the bias current and the modulation current drive the laser chip to send light signals. At this time, the emission of the optical signal is continuous. The burst control signal sent by the upper computer controls the burst opening or burst closing of the first switch, the second switch and the third switch, the burst opening or burst closing of the first switch, the second switch and the third switch controls the modulation current flowing through the first switch and the second switch to be burst opened or closed, and also controls the bias current flowing through the third switch to be burst opened or closed, so that the burst opening or burst closing of the light emitting device is controlled, and the optical power loss is reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

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 according to an embodiment of the present disclosure;

fig. 4 is an exploded schematic view of an optical module structure according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of an optical module provided in the embodiment of the present application with an upper case and a lower case removed;

fig. 6 is a circuit diagram for implementing burst on or burst off according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, 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 application.

One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer, it is necessary to perform interconversion between the electric signal and the optical signal.

The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical 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 an internal circuit board of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, grounding and the like; the optical module realizes optical connection with external optical fibers through an optical interface, the external optical fibers are connected in various ways, and various optical fiber connector types are derived; the method is characterized in that the electric connection is realized by using a golden finger at an electric interface, which becomes the mainstream connection mode of the optical module industry, and on the basis, the definition of pins on the golden finger forms various industry protocols/specifications; the optical connection mode realized by adopting the optical interface and the optical fiber connector becomes the mainstream connection mode of the optical module industry, on the basis, the optical fiber connector also forms various industry standards, such as an LC interface, an SC interface, an MPO interface and the like, the optical interface of the optical module also makes adaptive structural design aiming at the optical fiber connector, and the optical fiber adapters arranged at the optical interface are various.

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 the interconnection among the optical network terminal 100, the optical module 200, the optical fiber 101 and the network cable 103;

one end of the optical fiber 101 is connected with a far-end server, one end of the network cable 103 is connected with 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 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is made by the optical network terminal 100 having the optical module 200.

An optical interface of the optical module 200 is externally accessed to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; the electrical interface of the optical module 200 is externally connected to the optical network terminal 100, and establishes a bidirectional electrical signal connection with the optical network terminal 100; bidirectional interconversion of optical signals and electric signals is realized inside the optical module, so that information connection is established between the optical fiber and the optical network terminal; specifically, the optical signal from the optical fiber 101 is converted into an electrical signal by the optical module and then input to the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input to the optical fiber 101.

The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal has a network cable interface 104, which is used for accessing the network cable 103 and establishing a bidirectional electrical signal connection (generally, an electrical signal of an ethernet protocol, which is different from an electrical signal used by an optical module in protocol/type) with the network cable 103; the optical module 200 is connected to the network cable 103 through the optical network terminal 100, specifically, the optical network terminal 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 terminal serves as an upper computer of the optical module to monitor the operation of the optical module. The optical network terminal 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 a bidirectional signal transmission channel is established between the remote server and the local information processing equipment through the optical fiber, the optical module, the optical network terminal and a network cable.

Common local information processing apparatuses include routers, home switches, electronic computers, and the like; common optical network terminals include an optical network unit ONU, an optical line terminal OLT, a data center server, a data center switch, and the like.

Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 has a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electrical connector is arranged in the cage 106 and used for accessing an electrical interface (such as a gold finger) of the optical module; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into an optical network terminal, the electrical interface of the optical module is inserted into the electrical connector inside the cage 106, and the optical interface of the optical module is connected to the optical fiber 101.

The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, held by the cage, and the heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage.

Fig. 3 is a schematic view of an optical module according to an embodiment of the present disclosure, and fig. 4 is a schematic view of an exploded structure of an optical module according to an embodiment of the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in the embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, a light emitting device 400, and a light receiving device 500;

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 may be two ends (204, 205) in the same direction, or two openings in different directions; one of the openings is an electrical interface 204, and a gold finger of the circuit board extends out of the electrical interface 204 and is inserted into an upper computer such as an optical network terminal; the other opening is an optical interface 205 for external optical fiber access to connect the light emitting device 400 and the light receiving device 500 inside the optical module; the photoelectric devices such as the circuit board 300, the light emitting device 400, and the light receiving device 500 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 300, the light emitting device 400, the light receiving device 500 and other devices can be conveniently installed in the shells, 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 housing of the optical module is not made into an integrated component, and the integrated housing is not beneficial to the assembly of devices in the housing.

The unlocking component 203 is located on the outer wall of the wrapping cavity/lower shell 202, and is 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 component 203 is provided with a clamping component matched with the upper computer cage; the end of the unlocking component can be pulled to enable the unlocking component 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 by a clamping component of the unlocking component; by pulling the unlocking component, the clamping component of the unlocking component moves along with the unlocking component, so that the connection relation between the clamping component and the upper computer is changed, the clamping relation between the optical module and the upper computer is released, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 300 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a laser driver chip, a limiting amplifier chip, a clock data recovery CDR, a power management chip, and a data processing chip DSP).

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

The circuit board is generally a hard circuit board, and the hard circuit board can also realize a bearing effect due to the relatively hard material of the hard circuit board, for example, the hard circuit board can stably bear a chip; when the optical transceiver is positioned on the circuit board, the rigid circuit board can also provide stable bearing; 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.

And a light emitting device 400 electrically connected to the circuit board 300 for emitting a light signal. Specifically, the light emitting device 400 may be disposed on a surface of the circuit board 300, or may be electrically connected to the circuit board 300 through a flexible board.

And a light receiving device 500 electrically connected to the circuit board 300 for receiving the optical signal output by the external optical fiber. Specifically, the light receiving device 500 may be disposed on a surface of the circuit board 300, or may be electrically connected to the circuit board 300 through a flexible board.

Although both the light emitting device 400 and the light receiving device 500 may be disposed on the surface of the circuit board 300, and may be electrically connected to the circuit board 300 through a flexible board, in the embodiment of the present application, the light emitting device 400 and the light receiving device 500 are electrically connected to the circuit board 300 through a flexible board.

Fig. 5 is a schematic structural diagram of an optical module provided in the embodiment of the present application with an upper case and a lower case removed. Fig. 6 is a circuit diagram for implementing burst on or burst off according to an embodiment of the present disclosure. As shown in fig. 5 and 6, a light emitting device 400 provided in an embodiment of the present application includes a laser chip 401, and a circuit board 300 on which a laser driving chip 301, a first switch 302, a second switch 303, and a third switch 304 are disposed.

And a laser chip 401 disposed in the light emitting device 400, a first end of which is electrically connected to a power supply for controlling an emitted light signal according to the bias current and the modulation current. Since the first end of the laser chip 401 is electrically connected to the power supply, and the second end of the laser chip 401 is finally grounded, it can be known from the voltage drop that the laser chip 401 is turned on and current flows through the laser chip 401. The current flowing through the laser chip 401 includes a bias current and a modulation current. The bias current and the modulation current act on the laser chip 401 together, so that the laser chip 401 can work normally to emit optical signals. Wherein the bias current is constant, it causes the laser chip 401 to always operate in a linear region above the threshold current. The threshold current is the minimum current at which the laser chip 401 emits the optical signal. The modulation current is constantly changing, which changes with the change in the input voltage waveform. When the modulation current is small, the current flowing through the laser chip 401 is small; when the modulation current is large, the current flowing through the laser chip 401 is large.

The laser driving chip 301 is located on the surface of the circuit board, and is electrically connected with the electrical connector/gold finger of the circuit board directly or indirectly so as to receive an upper computer signal transmitted through the electrical connector/gold finger, and convert the signal from the upper computer into an electrical signal for driving the laser chip 401, wherein the electrical signal is generally embodied in a current form, and the laser chip 401 emits light under the driving of the current.

The laser driver chip 301 is generally electrically connected to the circuit board by wire bonding. The lead wire adopted by the routing process can be made of a material with better conductivity, such as: aluminum wire, copper wire, gold wire, etc. In the embodiment, the gold wire is used as the lead wire, so that the conductivity is better, the accuracy of signal transmission can be improved, and signal distortion is avoided. Specifically, the surface of the circuit board is provided with metal traces and metal pads, the metal traces can be used for transmitting electrical signals/high-speed electrical signals, and the metal pads are used for setting grounding.

In a specific embodiment, a large-area metal layer is arranged on the surface of the circuit board, the metal layer is communicated with a stratum in an intermediate layer of the circuit board through a via hole, and the via hole is positioned below the metal layer; the laser driving chip 301 is disposed on the metal layer.

The first end of the laser driving chip 301 is electrically connected to the first end of the first switch 302, the second end of the laser driving chip is electrically connected to the first end of the second switch 303, and the third end of the laser driving chip is grounded, so as to control the bias current and the modulation current flowing through the laser chip 401. The first terminal of the laser driving chip 301 is OUT^-The second terminal of the laser driving chip 301 is OUT⁺. When the laser driver chip 301 is not turned on, the bias current flowing through the laser chip 401 is not changed, and the modulation current flowing through the laser driver chip 401 is 0, so that the current flowing through the laser chip 401 is small. When the laser driving chip 301 is turned on, current flows through the laserThe bias current of the optical chip 401 is not changed, and the modulation current flowing through the laser driver chip 401 is increased, so that the current flowing through the laser chip 401 is large.

The laser driver chip 301 includes a second transistor 3011 and a third transistor 3012. The second transistor 3011 and the third transistor 3012 are arranged in mirror symmetry. Specifically, the collector of the second triode 3011 is electrically connected to a power supply, the base is electrically connected to the gold finger, and the emitter is electrically connected to the third triode 3012. And a collector of the third triode 3012 is electrically connected to the laser chip 401, a base of the third triode is electrically connected to the gold finger, and an emitter of the third triode 3011 is electrically connected to an emitter of the second triode 3011.

Because the bases of the second triode 3011 and the third triode 3012 are electrically connected to the upper computer through the gold finger, the second triode 3011 and the third triode 3012 both receive the DATA signal sent by the upper computer. The second triode 3011 and the third triode 3012 both control the conduction of the second triode 3011 and the third triode 3012 according to the DATA signal sent by the upper computer. Specifically, when the DATA signal is small, the second transistor 3011 and the third transistor 3012 cannot be turned on; when the DATA signal is large, the second transistor 3011 and the third transistor 3012 are turned on. When the third transistor 3012 is turned on, the laser chip 401 and the third transistor 3012 are connected, and the modulation current flowing through the laser chip 401 is large. When the third transistor 3012 cannot be turned on, the laser chip 401 and the third transistor 3012 cannot be connected, and the modulation current flowing through the laser chip 401 is 0.

Since the current flowing through the laser chip 401 includes a modulation current and a bias current, the bias current is a constant value, and when the modulation current is 0, the current flowing through the laser chip 401 is small; when the modulation current is large, the current flowing through the laser chip 401 is large.

The second end of the first switch 302 is electrically connected to the power supply, and the third end is electrically connected to the gold finger, for controlling the burst on or burst off of the modulation current flowing through the first switch 302 according to the burst control signal. The burst control signal is sent by the upper computer and transmitted to the third terminal of the first switch 302 through the gold finger. When the burst control signal is small (i.e., low level), the first switch 302 is not turned on, and the power supply, the first switch 302 and the second transistor 3011 of the laser driver chip 301 are not turned on, thereby controlling the modulation current flowing through the first switch 302 to be burst-off. When the burst control signal is at a high level, the first switch 302 is turned on, and the power supply, the first switch 302 and the second transistor 3011 of the laser driver chip 301 are connected to control the burst on of the modulation current flowing through the first switch 302.

A second end of the second switch 303 is electrically connected to the second end of the laser chip 401, and a third end of the second switch 303 is electrically connected to the gold finger, and is configured to control the burst on or burst off of the modulation current flowing through the second switch 303 according to the burst control signal. The burst control signal is sent by the upper computer and transmitted to the third terminal of the second switch 303 through the gold finger. When the burst control signal is at a low level, the second switch 303 is not turned on, the laser chip 401, the second switch 303 and the third transistor 3012 of the laser driving chip 301 are not turned on, and the modulation current flowing through the second switch 303 is controlled to be turned off in a burst mode. When the burst control signal is at a high level, the second switch 303 is turned on, and then the laser chip 401, the second switch 303 and the third triode 3012 of the laser driving chip 301 are connected to control the modulation current flowing through the second switch 303 to be burst on.

And a second end of the third switch 304 is electrically connected to the second end of the laser chip 401, and a third end of the third switch is electrically connected to the gold finger, and is used for controlling the burst on or burst off of the bias current flowing through the third switch 304 according to the burst control signal. The burst control signal is sent by the upper computer and transmitted to the third terminal of the third switch 304 through the gold finger. When the burst control signal is at a low level, the third switch 304 is turned off, the laser chip 401 and the third switch 304 are not turned on, and the bias current flowing through the third switch 304 is controlled to be turned off in a burst manner. When the burst control signal is at a high level, the third switch 304 is turned on, the laser chip 401 and the third switch 304 are connected, and the bias current flowing through the third switch 304 is controlled to be burst-turned on.

The first switch 302, the second switch 303, and the third switch 304 each include a first resistor 3021, a second resistor 3022, and a first transistor 3023. In particular, the method comprises the following steps of,

the first resistor 3021 has a first terminal serving as a third terminal of the first switch 302, the second switch 303, or the third switch 304, and a second terminal electrically connected to the base of the first transistor 3023, so as to prevent the base of the first transistor 3023 from being damaged due to excess current caused by a large burst control signal.

A second resistor 3022, having a first end electrically connected to the base of the first transistor 3023 and a second end electrically connected to the emitter of the first transistor 3023, is used to ensure that the first transistor 3023 is in an off state (i.e., cannot be turned on) when there is no burst control signal.

The first transistor 3023 has a collector as a first terminal of the first switch 302, the second switch 303, or the third switch 304, and an emitter as a second terminal of the first switch 302, the second switch 303, or the third switch 304. The base of the first triode 3023 receives a burst control signal sent by the host computer, and controls the conduction of the collector and the emitter of the first triode 3023 according to the burst control signal. Specifically, when the burst control signal is at a low level, the collector and the emitter of the first transistor 3023 cannot be turned on, and the first switch 302 is turned off. Similarly, the second switch 303 and the third switch 304 are turned off. When the burst control signal is at a high level, the collector and emitter of the first transistor 3023 are turned on, and the first switch 302 is turned on. Similarly, the second switch 303 and the third switch 304 are turned on.

Since the burst-on or burst-off time required in the relevant protocol standard of the optical module is within 128ns, the burst-on or burst-off time of the first switch 302, the second switch 303, and the third switch 304 is within 128 ns. Since the first switch 302 and the second switch 303 are used for transmitting high-speed signals, the first switch 302 and the second switch 303 both use high-speed switches with corresponding bandwidths. And the third switch 304 is only used for transmitting a dc signal, the third switch 304 can be a high speed switch or a normal switch.

As shown in fig. 6, the circuit board is further provided with a first matching circuit 305, a second matching circuit 306, a third matching circuit 307, and a compensation circuit 308.

A first terminal of the first matching circuit 305 is electrically connected to the power supply, and a second terminal thereof is electrically connected to the second terminal of the first switch 302. The first matching circuit 305 is a third resistor. And a third resistor, a first end of which is electrically connected to the power supply and a second end of which is electrically connected to the second end (collector) of the first switch 302, for compensating the impedance matching between the laser chip 401 and the laser driver chip 301.

A first end of the second matching circuit 306 is electrically connected to the second end of the laser chip 401, and a second end thereof is electrically connected to the second end of the second switch 303. The second matching circuit 306 is a fourth resistor. And a fourth resistor, a first end of which is electrically connected to the second end of the laser chip 401, and a second end of which is electrically connected to the second end (collector) of the second switch 303, for compensating impedance matching between the laser chip 401 and the laser driver chip 301.

A first terminal of the third matching circuit 307 is electrically connected to the second terminal of the laser chip 401, and a second terminal thereof is electrically connected to the second terminal of the third switch 304. The third matching circuit 307 is an inductor. And an inductor, a first end of which is electrically connected to the second end of the laser chip 401, and a second end of which is electrically connected to the second end (collector) of the third switch 304, for compensating impedance matching between the laser chip 401 and the laser driver chip 301.

The compensation circuit 308 includes a fifth resistor 3081 and a capacitor 3082, a first end of which is electrically connected to the second end of the laser chip 401, and a second end of which is grounded. Specifically, the fifth resistor 3081 has a first end electrically connected to the second end of the laser chip 401, and a second end electrically connected to the first end of the capacitor 3082. Capacitor 3082, the second terminal is grounded. The compensation circuit 308 formed by the fifth resistor 3081 and the capacitor 3082 is used for compensating the parasitic inductance of the lead wires of the laser chip 401 packaged in the light emitting device 400, so as to reduce overshoot and ringing caused by the parasitic inductance.

The application provides a light module, which comprises a circuit board and a light emitting device for emitting light signals. The circuit board is provided with a laser driving chip, a first switch, a second switch and a third switch. The light emitting device includes a laser chip. The laser chip is used for controlling the emitted light signal according to the bias current and the modulation current. And the first end of the laser driving chip is electrically connected with the first end of the first switch, the second end of the laser driving chip is electrically connected with the first end of the second switch, and the third end of the laser driving chip is grounded and used for controlling the bias current and the modulation current flowing through the laser chip. The second end of the first switch is electrically connected with the power supply, and the third end of the first switch is electrically connected with the golden finger and is used for controlling the burst opening or the burst closing of the modulation current flowing through the first switch according to the burst control signal; the second end of the second switch is electrically connected with the second end of the laser chip, and the third end of the second switch is electrically connected with the golden finger and is used for controlling the burst on or burst off of the modulation current flowing through the second switch according to the burst control signal; and the second end of the third switch is electrically connected with the second end of the laser chip, and the third end of the third switch is electrically connected with the golden finger and is used for controlling the burst opening or burst closing of the bias current flowing through the third switch according to the burst control signal. The laser driving chip controls bias current and modulation current flowing through the laser chip according to signals sent by the upper computer, and the bias current and the modulation current drive the laser chip to send light signals. At this time, the emission of the optical signal is continuous. The burst control signal sent by the upper computer controls the burst opening or burst closing of the first switch, the second switch and the third switch, the burst opening or burst closing of the first switch, the second switch and the third switch controls the modulation current flowing through the first switch and the second switch to be burst opened or closed, and also controls the bias current flowing through the third switch to be burst opened or closed, so that the burst opening or burst closing of the light emitting device is controlled, and the optical power loss is reduced.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should 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 in the embodiments of the present application.

Claims (8)

1. A light module, comprising:

a circuit board is provided with a plurality of circuit boards,

a light emitting device including a laser chip for emitting a light signal;

the first end of the laser chip is electrically connected with a power supply and is used for controlling an emitted optical signal according to the bias current and the modulation current;

the circuit board is provided with a laser driving chip, a first switch, a second switch and a third switch;

the first end of the laser driving chip is electrically connected with the first end of the first switch, the second end of the laser driving chip is electrically connected with the first end of the second switch, and the third end of the laser driving chip is grounded and used for controlling the bias current and the modulation current flowing through the laser chip;

the second end of the first switch is electrically connected with a power supply, and the third end of the first switch is electrically connected with the golden finger and is used for controlling the modulation current flowing through the first switch to be switched on or switched off in a burst mode according to a burst control signal;

the second end of the second switch is electrically connected with the second end of the laser chip, and the third end of the second switch is electrically connected with the golden finger and is used for controlling the modulation current flowing through the second switch to be switched on or switched off in a burst mode according to a burst control signal;

and the second end of the third switch is electrically connected with the second end of the laser chip, and the third end of the third switch is electrically connected with the golden finger and is used for controlling the bias current flowing through the third switch to be suddenly turned on or suddenly turned off according to a sudden control signal.

2. The optical module of claim 1, wherein the first switch, the second switch, and the third switch each comprise a first resistor, a second resistor, and a first transistor;

the first end of the first resistor is used as the third end of the first switch, the second switch or the third switch, and the second end of the first resistor is electrically connected with the base electrode of the first triode;

the first end of the second resistor is electrically connected with the base electrode of the triode, and the second end of the second resistor is electrically connected with the emitting electrode of the first triode;

the collector of the first triode is used as the first end of the first switch, the second switch or the third switch, and the emitter of the first triode is used as the second end of the first switch, the second switch or the third switch.

3. The light module of claim 2, wherein the burst on or burst off time of the first switch, the second switch, and the third switch are all within 128 ns.

4. The optical module according to claim 1, wherein a first matching circuit, a second matching circuit and a third matching circuit are further disposed on the circuit board;

the first end of the first matching circuit is electrically connected with the power supply, and the second end of the first matching circuit is electrically connected with the second end of the first switch;

the first end of the second matching circuit is electrically connected with the second end of the laser chip, and the second end of the second matching circuit is electrically connected with the second end of the second switch;

and the first end of the third matching circuit is electrically connected with the second end of the laser chip, and the second end of the third matching circuit is electrically connected with the second end of the third switch.

5. The optical module of claim 4, wherein the first matching circuit is a third resistor, the second matching circuit is a fourth resistor, and the third matching circuit is an inductor.

6. The optical module of claim 1, wherein a compensation circuit is further disposed on the circuit board;

and the first end of the compensation circuit is electrically connected with the second end of the laser chip, and the second end of the compensation circuit is grounded.

7. The light module of claim 6, wherein the compensation circuit comprises a fifth resistor and a capacitor;

the first end of the fifth resistor is electrically connected with the second end of the laser chip, and the second end of the fifth resistor is electrically connected with the first end of the capacitor;

and the second end of the capacitor is grounded.

8. The optical module according to claim 1, wherein the laser driving chip comprises a second transistor and a third transistor;

the collector of the second triode is electrically connected with the power supply, the base of the second triode is electrically connected with the golden finger, and the emitter of the second triode is electrically connected with the third triode;

and the collector of the third triode is electrically connected with the laser chip, the base of the third triode is electrically connected with the golden finger, and the emitter of the third triode is electrically connected with the emitter of the second triode.

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