CN114070411A

CN114070411A - Optical module

Info

Publication number: CN114070411A
Application number: CN202111370807.0A
Authority: CN
Inventors: 王斌; 金虎山
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2022-02-18
Anticipated expiration: 2041-11-18
Also published as: CN114070411B

Abstract

The application discloses optical module includes circuit board and light emission subassembly. The light emitting assembly includes a light emitting region and an electro-absorption modulation region. The circuit board is provided with an MCU, a bias circuit, a power supply circuit and a current detection circuit. And the bias circuit is connected with the luminous zone and used for providing bias current for the luminous zone so as to enable the luminous zone to emit light. And the power supply circuit is connected with the first end of the current detection circuit and used for supplying power to the electro-absorption modulation region. And the second end of the current detection circuit is connected with the first end of the electro-absorption modulation region and is used for detecting the current generated by the electro-absorption modulation region and converting the current into voltage. And the MCU monitors the optical power in real time according to the acquired voltage. In the application, the current detection circuit detects the current generated by the electro-absorption modulation region, so that the optical power monitoring of the light emitted by the light emitting region is realized, the cost can be effectively reduced, the design difficulty and the production process of the TOSA are reduced, and the optical power monitoring precision is met.

Description

Optical module

Technical Field

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

Background

The laser of the optical module comprises a directly modulated laser and an externally modulated laser. Since the directly modulated Laser is not suitable for long-distance and high-speed communication transmission, an externally modulated Laser, such as an Electro-absorption modulated Laser (EML), is generally used in long-distance optical communication transmission or high-speed optical communication transmission.

In the existing Optical module design, an Optical power detection circuit of the EML generally needs to add an MPD (Monitor PD Chip) in a TOSA (Transmitter Optical Subassembly) for sampling a backlight current, then convert the current into a positive voltage through a conversion circuit and supply the positive voltage to an MCU for voltage sampling, and the MCU monitors the Optical power by monitoring the voltage.

By adopting the method of increasing MPD sampling backlight current, for a multi-channel TOSA, each LD laser needs 1 MPD, and the design difficulty of the TOSA is increased; meanwhile, MPD mounting and coupling procedures are required to be added in TOSA production, and excessive or insufficient MPD coupling light can cause the optical power monitoring accuracy to exceed the standard; meanwhile, the distance between EMLs of the multi-channel TOSA is small, optical crosstalk exists in space, light strings of lasers of other channels can induce light currents to MPDs of the current channel, large errors are introduced for monitoring the optical power of the current channel, and therefore monitoring accuracy cannot meet requirements.

Disclosure of Invention

The application provides an optical module, which meets the optical power monitoring precision.

A light module, comprising:

a circuit board;

the light emitting component is connected with the circuit board, comprises a laser diode and an electric absorption modulation area and is used for emitting optical signals;

the circuit board is provided with an MCU, a bias circuit, a power supply circuit and a current detection circuit;

the bias circuit is connected with the luminous zone and used for providing bias current for the luminous zone so as to enable the luminous zone to emit light;

the power supply circuit is connected with the first end of the current detection circuit and used for supplying power to the electro-absorption modulation area;

the second end of the current detection circuit is connected with the first end of the electric absorption modulation region, the third end of the current detection circuit is connected with the MCU, and the current detection circuit is used for detecting current generated by light absorption of the electric absorption modulation region and converting the current into voltage;

and the MCU is used for monitoring the optical power in real time according to the acquired voltage.

Has the advantages that: the application provides an optical module, including the circuit board and the light emission subassembly of being connected with the circuit board. The light emitting component is used for emitting light signals. The light emitting assembly includes a light emitting region and an electro-absorption modulation region. The circuit board is provided with an MCU, a bias circuit, a power supply circuit and a current detection circuit. And the bias circuit is connected with the luminous zone and used for providing bias current for the luminous zone so as to enable the luminous zone to emit light. And the power supply circuit is connected with the first end of the current detection circuit and used for supplying power to the electro-absorption modulation region. Since light of different optical power emitted by the light emitting region generates different currents through the electro-absorption modulation region, the optical power of light emitted by the light emitting element can be monitored by detecting the currents generated by the electro-absorption modulation region. In order to detect the current generated by the electro-absorption modulation region, a current detection circuit is further arranged on the circuit board. And the second end of the current detection circuit is connected with the first end of the electric absorption modulation region and is used for detecting the current generated by the light absorbed by the electric absorption modulation region and converting the current into voltage. And the MCU is used for monitoring the optical power in real time according to the acquired voltage. In the application, the MPD and the voltage conversion circuit thereof are removed, and the light power of the light emitted by the light emitting area can be monitored only by detecting the current generated by the electro-absorption modulation area through the current detection circuit. This effectively reduces the cost; for the multi-channel TOSA, the design difficulty and the production process of the TOSA are reduced; meanwhile, the light emitting area and the electric absorption modulation area are both arranged in the light emitting assembly, so that the problem of optical crosstalk among multiple channels is avoided, and the optical power monitoring precision is met. In the application, the current detection circuit detects the current generated by the electro-absorption modulation region, so that the optical power monitoring of the light emitted by the light emitting region is realized, the cost can be effectively reduced, the design difficulty and the production process of the TOSA are reduced, and the optical power monitoring precision is met.

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 an electrical connection relationship of an optical communication terminal;

fig. 2 is a schematic structural diagram of an optical network terminal;

fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of an exploded structure of an optical module according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a circuit board according to an embodiment of the present disclosure;

fig. 6 is a functional diagram of optical power monitoring provided in an embodiment of the present application;

fig. 7 is a partial circuit diagram of optical power monitoring provided in an embodiment of the present application.

Detailed Description

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

In the optical communication technology, light is used to carry information to be transmitted, and an optical signal carrying the information is transmitted to information processing equipment such as a computer through information transmission equipment such as an optical fiber or an optical waveguide, so that the transmission of the information is completed. Because the optical signal has the passive transmission characteristic when being transmitted through the optical fiber or the optical waveguide, the information transmission with low cost and low loss can be realized. Further, since a signal transmitted by an information transmission device such as an optical fiber or an optical waveguide is an optical signal and a signal that can be recognized and processed by an information processing device such as a computer is an electrical signal, it is necessary to perform interconversion between the electrical signal and the optical signal in order to establish an 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.

The optical module realizes the function of interconversion between the optical signal and the electrical signal in the technical field of optical fiber communication. The optical module comprises an optical port and an electrical port, the optical module realizes optical communication with information transmission equipment such as optical fibers or optical waveguides and the like through the optical port, realizes electrical connection with an optical network terminal (such as an optical modem) through the electrical port, and the electrical connection is mainly used for realizing power supply, I2C signal transmission, data signal transmission, grounding and the like; the optical network terminal transmits the electric signal to the computer and other information processing equipment through a network cable or a wireless fidelity (Wi-Fi).

Fig. 1 is a diagram of optical communication system connections according to some embodiments. As shown in fig. 1, the optical communication system mainly includes a remote server 1000, a local information processing device 2000, an optical network terminal 100, an optical module 200, an optical fiber 101, and a network cable 103;

one end of the optical fiber 101 is connected to the remote server 1000, and the other end is connected to the optical network terminal 100 through the optical module 200. The optical fiber itself can support long-distance signal transmission, for example, signal transmission of several kilometers (6 kilometers to 8 kilometers), on the basis of which if a repeater is used, ultra-long-distance transmission can be theoretically achieved. Therefore, in a typical optical communication system, the distance between the remote server 1000 and the optical network terminal 100 may be several kilometers, tens of kilometers, or hundreds of kilometers.

One end of the network cable 103 is connected to the local information processing device 2000, and the other end is connected to the optical network terminal 100. The local information processing apparatus 2000 may be any one or several of the following apparatuses: router, switch, computer, cell-phone, panel computer, TV set etc..

The physical distance between the remote server 1000 and the optical network terminal 100 is greater than the physical distance between the local information processing apparatus 2000 and the optical network terminal 100. The connection between the local information processing device 2000 and the remote server 1000 is completed by the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is completed by the optical module 200 and the optical network terminal 100.

The optical module 200 includes an optical port and an electrical port. The optical port is configured to connect with the optical fiber 101, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101; the electrical port is configured to be accessed into the optical network terminal 100, so that the optical module 200 establishes a bidirectional electrical signal connection with the optical network terminal 100. The optical module 200 converts an optical signal and an electrical signal to each other, so that a connection is established between the optical fiber 101 and the optical network terminal 100. For example, an optical signal from the optical fiber 101 is converted into an electrical signal by the optical module 200 and then input to the optical network terminal 100, and an electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module 200 and input to the optical fiber 101.

The optical network terminal 100 includes a housing (housing) having a substantially rectangular parallelepiped shape, and an optical module interface 102 and a network cable interface 104 provided on the housing. The optical module interface 102 is configured to access the optical module 200, so that the optical network terminal 100 establishes a bidirectional electrical signal connection with the optical module 200; the network cable interface 104 is configured to access the network cable 103 such that the optical network terminal 100 establishes a bi-directional electrical signal connection with the network cable 103. The optical module 200 is connected to the network cable 103 via the optical network terminal 100. For example, the optical network terminal 100 transmits an electrical signal from the optical module 200 to the network cable 103, and transmits a signal from the network cable 103 to the optical module 200, so that the optical network terminal 100 can monitor the operation of the optical module 200 as an upper computer of the optical module 200. The upper computer of the Optical module 200 may include an Optical Line Terminal (OLT) and the like in addition to the Optical network Terminal 100.

The remote server 1000 establishes a bidirectional signal transmission channel with the local information processing device 2000 through the optical fiber 101, the optical module 200, the optical network terminal 100, and the network cable 103.

Fig. 2 is a structure diagram of an optical network terminal according to some embodiments, and fig. 2 only shows the structure of the optical module 200 of the optical network terminal 100 in order to clearly show the connection relationship between the optical module 200 and the optical network terminal 100. As shown in fig. 2, the optical network terminal 100 further includes a PCB circuit board 105 disposed in the housing, a cage 106 disposed on a surface of the PCB circuit board 105, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access an electrical port of the optical module 200; the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into a cage 106 of the optical network terminal 100, the cage 106 holds the optical module 200, and heat generated by the optical module 200 is conducted to the cage 106 and then diffused by a heat sink 107. After the optical module 200 is inserted into the cage 106, an electrical port of the optical module 200 is connected to an electrical connector inside the cage 106, and thus the optical module 200 establishes a bidirectional electrical signal connection with the optical network terminal 100. Further, the optical port of the optical module 200 is connected to the optical fiber 101, and the optical module 200 establishes bidirectional electrical signal connection with the optical fiber 100.

Fig. 3 is a diagram of an optical module provided according to some embodiments, and fig. 4 is an exploded structural view of an optical module according to some embodiments. As shown in fig. 3 and 4, the optical module 200 includes a housing, a circuit board 300 disposed in the housing, and an optical transceiver;

the shell comprises an upper shell 201 and a lower shell 202, wherein the upper shell 201 is covered on the lower shell 202 to form the shell with two

openings

204 and 205; the outer contour of the housing generally appears square.

In some embodiments, the lower housing 202 includes a bottom plate and two lower side plates disposed at both sides of the bottom plate and perpendicular to the bottom plate; the upper housing 201 includes a cover plate, and two upper side plates disposed on two sides of the cover plate and perpendicular to the cover plate, and is combined with the two side plates by two side walls to cover the upper housing 201 on the lower housing 202.

The direction of the connecting line of the two

openings

204 and 205 may be the same as the length direction of the optical module 200, or may not be the same as the length direction of the optical module 200. For example, the opening 204 is located at an end (left end in fig. 3) of the optical module 200, and the opening 205 is also located at an end (right end in fig. 3) of the optical module 200. Alternatively, the opening 204 is located at an end of the optical module 200, and the opening 205 is located at a side of the optical module 200. Wherein, the opening 204 is an electrical port, and the gold finger of the circuit board 300 extends out of the electrical port 204 and is inserted into an upper computer (such as the optical network terminal 100); the opening 205 is an optical port configured to receive the external optical fiber 101, so that the optical fiber 101 is connected to an optical transceiver inside the optical module 200.

The upper shell 201 and the lower shell 202 are combined in an assembly mode, so that devices such as the circuit board 300 and the optical transceiver can be conveniently installed in the shells, and the upper shell 201 and the lower shell 202 can form packaging protection for the devices. In addition, when the devices such as the circuit board 300 are assembled, the positioning components, the heat dissipation components and the electromagnetic shielding components of the devices are convenient to arrange, and the automatic implementation production is facilitated.

In some embodiments, the upper housing 201 and the lower housing 202 are generally made of metal materials, which is beneficial to achieve electromagnetic shielding and heat dissipation.

In some embodiments, the optical module 200 further includes an unlocking component 203 located on an outer wall of a housing thereof, and the unlocking component 203 is configured to realize a fixed connection between the optical module 200 and an upper computer or release the fixed connection between the optical module 200 and the upper computer.

Illustratively, the unlocking member 203 is located on the outer wall of the two lower side plates 2022 of the lower housing 202, and includes a snap-fit member that mates with a cage of an upper computer (e.g., the cage 106 of the optical network terminal 100). When the optical module 200 is inserted into the cage of the upper computer, the optical module 200 is fixed in the cage of the upper computer by the engaging member of the unlocking member 203; when the unlocking member 203 is pulled, the engaging member of the unlocking member 203 moves along with the unlocking member, and the connection relationship between the engaging member and the upper computer is changed, so that the engagement relationship between the optical module 200 and the upper computer is released, and the optical module 200 can be drawn out from the cage of the upper computer.

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

The circuit board 300 connects the above devices in the optical module 200 together according to circuit design through circuit routing to implement functions of power supply, electrical signal transmission, grounding, and the like.

The circuit board 300 is generally a rigid circuit board, which can also perform a bearing function due to its relatively rigid material, for example, the rigid circuit board can stably bear a chip; the hard circuit board can also be inserted into an electric connector in the cage of the upper computer, and in some embodiments disclosed in the application, 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.

Flexible circuit boards are also used in some optical modules; the flexible circuit board is generally used in combination with the rigid circuit board, and for example, the rigid circuit board may be connected to the optical transceiver device to supplement the rigid circuit board.

The optical transceiver includes an optical transmitter module 400 and an optical receiver module 500.

And a light emitting assembly 400 electrically connected to the circuit board 300. Specifically, the light emitting module 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.

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

An optical transmission assembly 400 for transmitting the optical signal. Specifically, the light emitting assembly 400 includes a light emitting chip in which a light emitting region (LD) and an Electro-absorption modulation region (EA) are disposed. The light emitting region emits light under the bias current. The electric absorption modulation region converts a part of light emitted by the light emitting region into current under the action of the power supply signal, and the other part of light is modulated to obtain an optical signal and emits the optical signal.

And an optical receiving module 500 for optical signals transmitted by the external optical fiber. Specifically, a photodiode is arranged in the light receiving component, receives an optical signal sent by an external optical fiber, and converts the optical signal into an electrical signal.

Fig. 5 is a schematic structural diagram of a circuit board according to an embodiment of the present application. Fig. 6 is a functional diagram of optical power monitoring provided in the embodiment of the present application. Fig. 7 is a partial circuit diagram of optical power monitoring provided in an embodiment of the present application. As shown in fig. 5 to 7, the circuit board 300 is provided with an MCU301, a bias circuit 302, a power supply circuit 303, a current detection circuit 304, a filter circuit 305, and a high-speed modulation drive circuit 306. In particular, the method comprises the following steps of,

the MCU301 is connected to a bias circuit 302, a power supply circuit 303, and a current detection circuit 304. Specifically, a first terminal of the MCU301 is connected to the bias circuit 302, and is configured to control the bias circuit 302 to generate a bias current. And a second end of the MCU301 is connected to the power supply circuit 303, and is configured to control a magnitude of the power supply signal output by the power supply circuit 303. And a third end of the MCU301 is connected with the current detection circuit 304 and is used for monitoring the optical power in real time according to the collected voltage.

And the MCU301 is used for monitoring the optical power in real time according to the acquired voltage. Specifically, when the optical power of the light emitted by the LD changes, the current generated by the electro-absorption modulation region also changes, so that the current detected by the current detection circuit 304 changes, and the voltage output by the current detection circuit 304 and collected by the MCU301 changes. The MCU301 can realize real-time monitoring of the optical power according to the collected voltage.

And a bias circuit 302, having a first terminal connected to the first terminal of the MCU301 and a second terminal connected to the light emitting region, for providing a bias current to the light emitting region to make the light emitting region emit light. Specifically, the bias circuit 302 generates a bias current under the action of the MCU301 and transmits the bias current to the light emitting region. The light emitting region emits light under the bias current.

And a first end of the power supply circuit 303 is connected with a second end of the MCU301, and a second end of the power supply circuit is connected with a first end of the current detection circuit 304, for supplying power to the electro-absorption modulation region. Specifically, the power supply circuit 303 generates a power supply signal under the action of the MCU301, and transmits the power supply signal to the electro-absorption modulation region. The power supply signal is a negative voltage, and the power supply signal is a direct current voltage.

The power supply circuit 303 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a first operational amplifier OPA 1. In particular, the method comprises the following steps of,

a seventh resistor R7 has a first terminal connected to the inverting input terminal of the first operational amplifier OPA1 and a second terminal connected to the output terminal of the first operational amplifier OPA 1.

The eighth resistor R8 has a first terminal connected to ground and a second terminal connected to the positive input terminal of the first operational amplifier OPA 1.

And a first end of the ninth resistor R9 is connected with the MCU, and a second end of the ninth resistor R9 is connected with a first end of the seventh resistor R7. A first end of the ninth resistor R9 is a first end of the power supply circuit 303.

The first operational amplifier OPA1 has a forward input terminal connected to the second terminal of the eighth resistor R8, an inverting input terminal connected to the first terminal of the seventh resistor R7, and an output terminal connected to the second terminal of the seventh resistor R7 and the first terminal of the current detection circuit 305. The output terminal of the first operational amplifier OPA1 is the second terminal of the power supply circuit 303.

The negative power supply terminal of the first operational amplifier OPA1 is connected to the negative power supply terminal of the negative voltage conversion circuit, and the positive power supply terminal of the first operational amplifier OPA1 is grounded. Wherein the negative voltage conversion circuit converts a positive voltage + VCC into a negative voltage-VCC.

Since the second terminal of the ninth resistor R9 and the inverting input terminal of the first operational amplifier OPA1 are both connected to the first terminal of the seventh resistor R7, the second terminal of the ninth resistor R9 is connected to the inverting input terminal of the first operational amplifier OPA 1.

The operating principle of the power supply circuit 303 is: the first end of the MCU generates a positive voltage DAC _ VEA control signal that is converted to a negative voltage VEA after passing through the reverse voltage amplification circuit of the OPA 1. In particular, the method comprises the following steps of,

because the forward input terminal and the reverse input terminal of the first operational amplifier are 'virtual short and virtual broken', the voltages of the forward input terminal and the reverse input terminal of the first operational amplifier are equal, namely: v₁₊＝V_1-(1) (ii) a The currents at the positive input terminal and the negative input terminal of the first operational amplifier are both 0, i.e. I₁₊＝I_1-＝0(2)。

Since the currents of the positive input terminal and the negative input terminal of the first operational amplifier are both 0, the seventh resistor R7 is connected in series with the ninth resistor R9. Since the seventh resistor R7 is connected in series with the ninth resistor R9, the current flowing through the seventh resistor R7 is equal to the current flowing through the ninth resistor R9. Namely: (DAC _ VEA-V)₁-)/R9＝(VEA-V_1-)/R7(3)。

Due to V₁And 0, then VEA-1 DAC _ VEA R7/R9 (4).

The first operational amplifier OPA1 may be configured as an equal-ratio inverting voltage amplifying circuit (i.e., R7 — R9), and VEA — 1 DAC _ VEA (5). The positive voltage DAC _ VEA generated by the MCU is converted into a negative voltage VEA by the inverting action of the first operational amplifier OPA 1.

Since light of different optical power emitted by the light emitting region generates different currents through the electro-absorption modulation region, the optical power of light emitted by the light emitting element can be monitored by detecting the currents generated by the electro-absorption modulation region. In order to detect the current generated by the electro-absorption modulation region, a current detection circuit 304 is provided on the circuit board.

And a second end of the current detection circuit 304 is connected with the first end of the electro-absorption modulation region, and a third end of the current detection circuit is connected with a third end of the MCU301, and is used for detecting current generated by light absorption of the electro-absorption modulation region and converting the current into voltage. The second end of the electro-absorption modulation region is grounded. Specifically, the current detection circuit 304 detects a current generated by light absorbed by the electro-absorption modulation region and converts the current into a voltage.

The current detection circuit 304 includes a first resistor R1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a second operational amplifier OPA 2. In particular, the method comprises the following steps of,

a first resistor R1 has a first terminal connected to the second terminal of the power supply circuit 303 and a second terminal connected to the first terminal of the electro-absorption modulation region. The first end of the first resistor R1 is the first end of the current detection circuit 304, and the second end of the first resistor R1 is the second end of the current detection circuit 304.

The third resistor R3 has a first end connected to ground and a second end connected to the second end of the fourth resistor R4.

The first end of the fourth resistor R4 is connected to the second end of the first resistor R1, and the second end is connected to the second end of the third resistor R3.

A fifth resistor R5 has a first terminal connected to the first terminal of the first resistor R1 and a second terminal connected to the inverting input terminal of the second operational amplifier OPA 2.

Since the second terminal of the power supply circuit 303 and the first terminal of the fifth resistor R5 are both connected to the first terminal of the first resistor R1, the second terminal of the power supply circuit 303 and the first terminal of the fifth resistor R5 are connected.

And a first end of the sixth resistor R6 is connected with a second end of the fifth resistor R5, and a second end of the sixth resistor R6 is connected with the MCU.

Since the inverting input terminal of the second operational amplifier OPA2 and the first terminal of the sixth resistor R6 are both connected to the second terminal of the fifth resistor R5, the first terminal of the sixth resistor R6 is connected to the inverting input terminal of the second operational amplifier OPA 2.

The positive input end of the second operational amplifier OPA2 is connected to the second end of the fourth resistor R4, the negative input end thereof is connected to the second end of the fifth resistor R5, and the output end thereof is connected to the second end of the sixth resistor R6.

Since the output terminals of the MCU and the second operational amplifier OPA2 are both connected to the second terminal of the sixth resistor R6, the output terminals of the MCU and the second operational amplifier OPA2 are connected.

The negative power supply terminal of the second operational amplifier OPA2 is connected to the negative power supply terminal of the negative voltage conversion circuit, and the positive power supply terminal of the second operational amplifier OPA2 is connected to the positive power supply terminal of the negative voltage conversion circuit.

The operating principle of the current detection circuit 304 is as follows: the current of EA is sampled by the first resistor R1, converted into a voltage ADC _ IEA after differential amplification by the second operational amplifier OPA2, and then acquired by the MCU. When the optical power of light emitted by the LD changes, the current generated by light absorbed by the electro-absorption modulation region also changes, and then the current detected by the current detection circuit 304 changes, and the voltage acquired by the MCU301 after conversion by the current detection circuit 304 changes, so that the purpose of monitoring the optical power can be achieved by monitoring the EA current.

Because the forward input end and the reverse input end of the second operational amplifier are 'virtual short and virtual break', the voltages of the forward input end and the reverse input end of the second operational amplifier are equal, namely: v₂₊＝V_2-(6) (ii) a The currents at the positive input terminal and the negative input terminal of the second operational amplifier are both 0, i.e. I₂₊＝I_2-＝0(7)。

Since the currents of the positive input terminal and the negative input terminal of the second operational amplifier are both 0, the third resistor R3 is connected in series with the fourth resistor R4, and the fifth resistor R5 is connected in series with the sixth resistor R6. Since the third resistor R3 is connected in series with the fourth resistor R4 and the fifth resistor R5 is connected in series with the sixth resistor R6, the current flowing through the third resistor R3 is equal to the current flowing through the fourth resistor R4, and the current flowing through the fifth resistor R5 is equal to the current flowing through the sixth resistor R6. Namely: (VEA _ BIAS-V)₂₊)/R4＝V₂₊/R3(8)，(VEA-V_2-)/R5＝(V_2-ADC _ IEA)/R6(9), wherein VEA _ BIAS is the voltage at the second end of the first resistor R1.

When the power supply circuit 303 does not supply power, EA does not start to work and cannot generate current, and there is no current flowing through the first resistor R1, so the voltage at the second end of the second resistor R1 is VEA. When the power supply circuit 303 starts supplying power, EA starts to work, light emitted by the LD irradiates EA, EA generates current, the current generated by EA flows through the first resistor, and the voltage at the second end of the second resistor R1 is VEA _ BIAS.

If the selected resistance relationship is R3/R4 ═ R6/R5, then ADC _ IEA ═ R6/R5 (10).

When R6/R5 is set to 10, ADC _ IEA is set to 10 (VEA _ BIAS-VEA) (11).

Since IEA is the current through EA and is equal to the current through R1, then VEA _ BIAS-VEA is IEA R1 (12).

If R1 ═ 1 ohm, R4 ═ R5 ═ 10K, R6 ═ R3 ═ 100K, then ADC _ IEA ═ 10(13) is provided.

According to the formula (13), when the LD optical power changes, the EA current changes, and the MCU monitors the value of ADC _ IEA to realize real-time monitoring of the EML optical power.

The current detection circuit 304 detects the current generated by the electro-absorption modulation region and converts the current into a voltage, and the MCU collects the voltage to monitor the optical power of the light emitted by the light emitting region. In the application, the MPD and the voltage conversion circuit thereof are removed, and the light power of the light emitted by the light emitting area can be monitored only by detecting the current generated by the electro-absorption modulation area through the current detection circuit. This effectively reduces the cost; for the multi-channel TOSA, the design difficulty and the production process of the TOSA are reduced; meanwhile, the light emitting area and the electric absorption modulation area are both arranged in the light emitting assembly, so that the problem of optical crosstalk among multiple channels is avoided, and the optical power monitoring precision is met.

And a filter circuit 305, having a first terminal connected to the second terminal of the current detection circuit 304, and a second terminal connected to the first terminal of the electro-absorption modulation region for filtering. In particular, the method comprises the following steps of,

the filter circuit 305 includes a second resistor R2, an inductor L1, a first bead B1, and a second bead B2. In particular, the method comprises the following steps of,

the first end of the second resistor R2 is connected to the second end of the first resistor R1 of the current detection circuit 304, and the second end is connected to the second end of the inductor L1. A first terminal of the second resistor R2 is a first terminal of the filter circuit 305.

The inductor L1 has a first terminal connected to the second terminal of the first resistor R1 of the current detection circuit 304, and a second terminal connected to the second terminal of the second resistor R2.

The primary function of inductor L1 is to prevent power supply ripple on VEA _ BIAS from entering EA to affect the laser eye performance, while preventing power supply ripple from entering the high speed modulation driver circuit to affect its operating performance.

Since the first ends of the second resistor R2 and the inductor L1 are both connected to the second end of the first resistor R1 of the current detection circuit 304, and the second end of the second resistor R2 is connected to the second end of the inductor L1, the second resistor R2 and the inductor L1 are connected in parallel.

The resistor R2 is connected in parallel with the inductor L1 to increase the bandwidth of the filter circuit and better prevent power supply ripples.

The first magnetic bead B1 has a first end connected to the second end of the inductor L1, and a second end connected to the first end of the second magnetic bead B2.

And a second magnetic bead B2, the first end of which is connected with the second end of the first magnetic bead B1, and the second end of which is connected with the first end of the electroabsorption modulation region. The second end of the second magnetic bead B2 is the second end of the filter circuit 305.

B1 and B2 are high impedance magnetic beads, which can be selected according to the actual data transmission rate of the optical module. The B1 and B2 form a 2-level magnetic bead network by being connected in series, and the main function of the network is to prevent (some) high-speed data signals loaded on EA from flowing away to the VEA circuit by the high bandwidth and high impedance of the magnetic beads, so that the bandwidth of the high-speed signals is reduced and the optical eye diagram is influenced.

And a high-speed modulation driving circuit 306 connected to the first end of the electro-absorption modulation region for providing a high-speed data signal to the electro-absorption modulation region. The high-speed data signal modulates the light emitted by the LD absorbed by the electro-absorption modulation region to obtain an optical signal.

The circuit board 300 is also provided with a thermoelectric refrigerator control circuit. And the first end of the thermoelectric refrigerator control circuit is connected with the MCU, and the second end of the thermoelectric refrigerator control circuit is connected with the light emission assembly and used for controlling the temperature of the light emission assembly so that the light emission assembly works at a constant temperature.

Because the power supply signal provided by the power supply circuit 303 to the electro-absorption modulation region is a dc voltage, the power supply signal is also a dc voltage when passing through the current detection circuit 304, and is also a dc voltage when passing through the filter circuit 305 and then provided to the electro-absorption modulation region, the high-speed data signal provided by the high-speed modulation drive circuit 306 to the electro-absorption modulation region is an ac voltage, and the dc voltage and the ac voltage do not interfere with each other, the filter circuit 305 and the high-speed modulation drive circuit 306 are both connected to the first end (i.e., the same pin) of the electro-absorption modulation region.

The application provides an optical module, including the circuit board and the light emission subassembly of being connected with the circuit board. The light emitting component is used for emitting light signals. The light emitting assembly includes a light emitting region and an electro-absorption modulation region. The circuit board is provided with an MCU, a bias circuit, a power supply circuit and a current detection circuit. And the bias circuit is connected with the luminous zone and used for providing bias current for the luminous zone so as to enable the luminous zone to emit light. And the power supply circuit is connected with the first end of the current detection circuit and used for supplying power to the electro-absorption modulation region. Since light of different optical power emitted by the light emitting region generates different currents through the electro-absorption modulation region, the optical power of light emitted by the light emitting element can be monitored by detecting the currents generated by the electro-absorption modulation region. In order to detect the current generated by the electro-absorption modulation region, a current detection circuit is further arranged on the circuit board. And the second end of the current detection circuit is connected with the electric absorption modulation region and is used for detecting the current generated by the light absorbed by the electric absorption modulation region and converting the current into voltage. And the MCU is used for monitoring the optical power in real time according to the acquired voltage. In the application, the MPD and the voltage conversion circuit thereof are removed, and the light power of the light emitted by the light emitting area can be monitored only by detecting the current generated by the electro-absorption modulation area through the current detection circuit. This effectively reduces the cost; for the multi-channel TOSA, the design difficulty and the production process of the TOSA are reduced; meanwhile, the light emitting area and the electric absorption modulation area are both arranged in the light emitting assembly, so that the problem of optical crosstalk among multiple channels is avoided, and the optical power monitoring precision is met. In the application, the current detection circuit detects the current generated by the electro-absorption modulation region, so that the optical power monitoring of the light emitted by the light emitting region is realized, the cost can be effectively reduced, the design difficulty and the production process of the TOSA are reduced, and the optical power monitoring precision is met.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; 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;

the light emitting component is connected with the circuit board, comprises a light emitting area and an electric absorption modulation area and is used for emitting optical signals;

the power supply circuit is connected with the first end of the current detection circuit and used for supplying power to the electro-absorption modulation region;

the second end of the current detection circuit is connected with the first end of the electro-absorption modulation region, and the third end of the current detection circuit is connected with the MCU and used for detecting current generated by light absorption of the electro-absorption modulation region and converting the current into voltage;

2. The light module of claim 1, wherein the current detection circuit comprises:

the first end of the first resistor is connected with the second end of the power supply circuit, and the second end of the first resistor is connected with the first end of the electro-absorption modulation region;

a third resistor, the first end of which is grounded;

a first end of the fourth resistor is connected with a second end of the first resistor, and a second end of the fourth resistor is connected with a second end of the third resistor;

a fifth resistor, a first end of which is connected with the first end of the first resistor;

a first end of the sixth resistor is connected with a second end of the fifth resistor, and the second end of the sixth resistor is connected with the MCU;

and a positive input end of the second operational amplifier is connected with the second end of the fourth resistor, a negative input end of the second operational amplifier is connected with the second end of the fifth resistor, and an output end of the second operational amplifier is connected with the second end of the sixth resistor.

3. The optical module according to claim 1, wherein a high-speed modulation driving circuit is further disposed on the circuit board;

the high-speed modulation driving circuit is connected with the first end of the electro-absorption modulation area and used for providing a high-speed data signal for the electro-absorption modulation area, wherein the high-speed data signal is alternating-current voltage and is different from a power supply signal provided by the power supply circuit, and the power supply signal is direct-current voltage.

4. The light module of claim 1, wherein the power supply circuit comprises:

a seventh resistor;

the first end of the eighth resistor is grounded;

a ninth resistor, a first end of which is connected with the MCU, and a second end of which is connected with a first end of the seventh resistor;

and a positive input end of the first operational amplifier is connected with the second end of the eighth resistor, a negative input end of the first operational amplifier is connected with the first end of the seventh resistor, and an output end of the first operational amplifier is connected with the second end of the seventh resistor.

5. The optical module according to claim 1, wherein a filter circuit is further disposed on the circuit board;

and the first end of the filter circuit is connected with the second end of the current detection circuit, and the second end of the filter circuit is connected with the first end of the electro-absorption modulation region and used for filtering.

6. The light module of claim 5, wherein the filter circuit comprises:

a first end of the second resistor is connected with a second end of the first resistor;

the first end of the inductor is connected with the second end of the first resistor, and the second end of the inductor is connected with the second end of the second resistor;

the first end of the first magnetic bead is connected with the second end of the inductor;

and the first end of the second magnetic bead is connected with the second end of the first magnetic bead, and the second end of the second magnetic bead is connected with the first end of the electroabsorption modulation region.

7. The optical module of claim 1, wherein the circuit board further has a thermoelectric cooler control circuit disposed thereon;

and the first end of the thermoelectric refrigerator control circuit is connected with the MCU, and the second end of the thermoelectric refrigerator control circuit is connected with the light emitting assembly.