CN112152722A

CN112152722A - Optical module

Info

Publication number: CN112152722A
Application number: CN201910562559.6A
Authority: CN
Inventors: 王力
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2019-06-26
Filing date: 2019-06-26
Publication date: 2020-12-29
Also published as: CN112438027B; WO2020259382A1; CN112438027A

Abstract

The invention provides an optical module, and relates to the technical field of optical fiber communication. In the optical module provided by the embodiment of the invention, the optical receiving chip outputs the first mixed frequency electric signal to the transimpedance amplification chip, the transimpedance amplification chip outputs the second mixed frequency electric signal to the amplitude limiting amplification chip, and the amplitude limiting amplification chip outputs the high-frequency electric signal, so that the high-frequency electric signal is received; the first low-pass filter circuit receives a third mixed frequency electric signal, and the third mixed frequency electric signal is a mirror image signal of the first mixed frequency electric signal; the first low-pass filter circuit outputs a first low-frequency electric signal to the second low-pass filter circuit, and the first low-frequency signal is processed by the second low-pass filter circuit to generate a decision threshold electric signal; the two input ends of the comparison circuit respectively input the second low-frequency electric signal and the judgment threshold electric signal, and the comparison circuit outputs the third low-frequency electric signal to the processor, so that the low-frequency electric signal is received.

Description

Optical module

Technical Field

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

Background

With the development of optical fiber communication technology, in some optical fiber communication fields, it is required to load low-frequency signals on an original high-speed service channel. For example, the FSAN proposes to add an Auxiliary Management and Control Channel (AMCC) in the point-to-point dense wavelength division multiplexing passive optical network, where the transmission rate of the AMCC is generally below 100Kbit/s, that is, the AMCC belongs to a low frequency signal. Therefore, the PTP WDM PON network is required to carry both the original high-speed service signals and the low-frequency signals such as AMCC.

In the PTP WDM PON network, both receiving and transmitting of optical signals are completed by an optical module, however, in the prior art, the optical module can only receive and transmit high-frequency digital service signals, but cannot receive and transmit low-frequency signals.

Therefore, the optical module in the prior art cannot receive a mixed signal simultaneously carrying a high frequency signal and a low frequency signal.

Disclosure of Invention

The embodiment of the invention provides an optical module to receive a high-frequency and low-frequency mixed signal.

In order to achieve the above purpose, the embodiment of the present invention adopts the following technical solutions:

on one hand, the embodiment of the invention provides an optical module, which comprises an optical receiving chip, a transimpedance amplification chip, an amplitude limiting amplification chip, a first low-pass filter circuit, a second low-pass filter circuit, a comparison circuit and a microprocessor; the transimpedance amplification chip is electrically connected with the light receiving chip, the amplitude limiting amplification chip and the first low-pass filter circuit respectively; the optical receiving chip outputs a first mixed frequency electric signal to the transimpedance amplification chip; the transimpedance amplification chip outputs a second mixed frequency electric signal to the amplitude limiting amplification chip; the amplitude limiting amplification chip outputs a high-frequency electric signal; the transimpedance amplification chip outputs a third mixed frequency electric signal to the first low-pass filter circuit; the third mixed frequency electric signal is a mirror image signal of the first mixed frequency electric signal; the second low-pass filter circuit is electrically connected with the first low-pass filter circuit, and the first low-pass filter circuit outputs a first low-frequency electric signal to the second low-pass filter circuit; the first input end of the comparison circuit is electrically connected with the first low-pass filter circuit, the second input end of the comparison circuit is electrically connected with the second low-pass filter circuit, the output end of the comparison circuit is connected with the microprocessor, and the first low-pass filter circuit inputs a second low-frequency electric signal to the comparison circuit; the second low-pass filter circuit inputs a decision threshold electric signal to the comparison circuit; the comparison circuit outputs a third low frequency electrical signal to the microprocessor.

On the other hand, an embodiment of the present invention provides an optical module, including a light receiving chip, a boost mirror circuit, a transimpedance amplification chip, an amplitude limiting amplification chip, a first low-pass filter circuit, a second low-pass filter circuit, a comparison circuit, and a microprocessor; the transimpedance amplification chip is electrically connected with the light receiving chip and the amplitude limiting amplification chip respectively; the optical receiving chip outputs a first mixed frequency electric signal to the transimpedance amplification chip; the transimpedance amplification chip outputs a second mixed frequency electric signal to the amplitude limiting amplification chip, and the amplitude limiting amplification chip outputs a high-frequency electric signal; the boosting mirror circuit is respectively electrically connected with the light receiving chip and the first low-pass filter circuit; the boosting mirror circuit outputs working high voltage to the light receiving chip; the boosting mirror circuit outputs a mirror electric signal of the first mixed frequency electric signal to the first low-pass filter circuit; the second low-pass filter circuit is electrically connected with the first low-pass filter circuit, and the first low-pass filter circuit outputs a first low-frequency electric signal to the second low-pass filter circuit; the first input end of the comparison circuit is electrically connected with the first low-pass filter circuit, the second input end of the comparison circuit is electrically connected with the second low-pass filter circuit, and the output end of the comparison circuit is connected with the microprocessor; the first low-pass filter circuit inputs a second low-frequency electric signal to the comparison circuit; the second low-pass filter circuit inputs a decision threshold electric signal to the comparison circuit; the comparison circuit outputs a third low frequency electrical signal to the microprocessor.

In the optical module provided by the embodiment of the invention, the optical receiving chip outputs the first mixed frequency electric signal to the transimpedance amplification chip, the transimpedance amplification chip outputs the second mixed frequency electric signal to the amplitude limiting amplification chip, and the amplitude limiting amplification chip outputs the high-frequency electric signal, so that the high-frequency electric signal is received; the first low-pass filter circuit receives a third mixed frequency electric signal, and the third mixed frequency electric signal is a mirror image signal of the first mixed frequency electric signal; the first low-pass filter circuit outputs a first low-frequency electric signal to the second low-pass filter circuit, and the first low-frequency signal is processed by the second low-pass filter circuit to generate a decision threshold electric signal; the two input ends of the comparison circuit respectively input the second low-frequency electric signal and the judgment threshold electric signal, and the comparison circuit outputs the third low-frequency electric signal to the processor, so that the low-frequency electric signal is received.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, 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 invention, and it is obvious for those skilled in the art that other drawings can be obtained according to 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 invention;

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

fig. 5 is a schematic diagram of an exploded structure of a receiving end (local) of an optical module according to an embodiment of the present invention;

FIG. 6 is an enlarged view of a portion of the area A in FIG. 5;

FIG. 7 is a partial enlarged view of the area B in FIG. 5;

fig. 8 is another schematic structural diagram of an optical module according to an embodiment of the present invention;

FIG. 9 is a circuit diagram of the optical module shown in FIG. 8;

fig. 10 is a schematic diagram of a related circuit structure of a low-pass amplifying circuit according to an embodiment of the invention;

FIG. 11 is a schematic diagram of voltage signal conversion implemented by the circuit of FIG. 10;

fig. 12 is a schematic structural diagram of a second low-pass filter circuit according to an embodiment of the present invention;

FIG. 13 is a schematic diagram of voltage signal conversion implemented by the circuit of FIG. 12;

FIG. 14 is a schematic diagram of a comparison circuit according to an embodiment of the present invention;

fig. 15 is a schematic diagram of voltage signal conversion of the comparison circuit in fig. 14.

Detailed Description

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

Optical communication enables signals to be transmitted using two different carriers, electrical and optical. Optical signals carrying information are transmitted in the optical waveguide for optical fiber communication, and the information transmission with low cost and low loss can be realized by utilizing the passive transmission characteristic of light in the optical waveguide such as the optical fiber; the information processing devices such as computers use electrical signals, which requires the interconversion between electrical signals and optical signals in the optical fiber communication system.

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

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

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

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

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

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

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

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

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

Fig. 3 is a schematic diagram of an optical module structure according to an embodiment of the present invention, and fig. 4 is an exploded schematic diagram of an optical module structure according to an embodiment of the present invention, as shown in fig. 3 and fig. 4, an optical module 200 according to an embodiment of the present invention includes an upper housing 201, a lower housing 202, an unlocking handle 203, a circuit board 300, a light emission submodule 301, and a light reception submodule 400.

The upper shell 201 and the lower shell 202 form a package cavity with two openings, specifically, two ends of the package cavity are opened (204, 205) in the same direction, or two openings in different directions are opened; one of the openings is an electrical port 204 for inserting into an upper computer such as an optical network unit, the other opening is an optical port 205 for connecting an external optical fiber to an internal optical fiber, and the photoelectric devices such as the circuit board 300, the light emission sub-module 301 and the light reception sub-module 400 are positioned in the packaging cavity.

The upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; the assembly mode that adopts upper casing, lower casing to combine is convenient for install devices such as circuit board in the casing, generally can not make the casing of optical module structure as an organic whole, like this when devices such as assembly circuit board, locating component, heat dissipation and electromagnetic shield structure can't install, also do not do benefit to production automation yet.

The unlocking handle 203 is positioned on the outer wall of the cavity/lower shell 202, and the tail end of the unlocking handle can be pulled to enable the unlocking handle to relatively move on the surface of the outer wall; when the optical module is inserted into the upper computer, the unlocking handle fixes the optical module in the cage of the upper computer, and the clamping relation between the optical module and the upper computer is released by pulling the unlocking handle, so that the optical module can be drawn out from the cage of the upper computer.

The circuit board is arranged in a packaging cavity formed by the upper shell and the shell, and the circuit board is provided with chips, capacitors, resistors and other electric devices. The method comprises the following steps of selecting chips to be set according to the requirements of products, wherein common chips comprise a microprocessor MCU, a clock data recovery chip CDR, a laser driving chip, a transimpedance amplifier TIA chip, an amplitude limiting amplifier LA chip, a power management chip and the like.

The transimpedance amplifier chip is closely associated with the light receiving chip, the short-distance wiring design can ensure good received signal quality, and in one packaging form of the optical module, the transimpedance amplifier chip and the light receiving chip are packaged together in an independent packaging body, such as the same coaxial tube shell TO or the same square cavity; the independent packaging body is independent of the circuit board, and the light receiving chip and the foot-spanning amplifying chip are electrically connected with the circuit board through the independent packaging body; in another package form of the optical module, the light receiving chip and the transimpedance amplifier chip may be disposed on a surface of the circuit board without using a separate package. Of course, the light receiving chip can be packaged independently, and the transimpedance amplification chip is arranged on the circuit board, so that the received signal quality can meet certain relatively low requirements.

The chip on the circuit board can be an all-in-one chip, for example, a laser driving chip and an MCU chip are fused into a chip, and a laser driving chip, a limiting amplification chip and an MCU chip are also fused into a chip, wherein the chip is the integration of the circuit, but the functions of all the circuits do not disappear due to the integration, and only the integration of the circuit forms occurs. Therefore, when the circuit board is provided with three independent chips, namely the MCU, the laser driving chip and the amplitude limiting amplification chip, the scheme is equivalent to that of arranging a single chip with three functions in one on the circuit.

The surface of the end part of the circuit board is provided with a golden finger, the golden finger consists of one pin which is mutually independent, the circuit board is inserted into an electric connector in the cage, and the golden finger is electrically connected with an upper computer.

The circuit board is a carrier of main electric elements of the optical module, the electric elements which are not arranged on the circuit board are finally electrically connected with the circuit board, and the electric connector on the circuit board realizes the electric connection of the optical module and an upper computer thereof. The electrical connector typically used by the optical module is a gold finger.

The optical module further includes a transmitter optical subassembly and a receiver optical subassembly, which may be collectively referred to as an optical subassembly. Fig. 4 is an exploded view of an optical module according to an embodiment of the present invention, and as shown in fig. 4, the optical module according to the embodiment of the present invention includes a tosa 301 and a rosa 400, and the tosa and the rosa are arranged on the surface of a circuit board in a staggered manner, which is beneficial to achieve a better electromagnetic shielding effect.

The tosa 301 is disposed on the surface of the circuit board 300, and in another common packaging method (such as a coaxial TO package), the tosa is packaged independently, physically separated from the circuit board, and electrically connected through a flexible board; the rosa 400 is disposed on the surface of the circuit board 300, and in another common packaging method (such as a coaxial TO package), the rosa is packaged separately and physically separated from the circuit board, and is electrically connected through a flexible board.

The industry provides a mixed frequency optical signal communication demand at present, wherein a path of low frequency signal is superposed on a path of high frequency signal, and two paths of signals with different frequencies are transmitted through light with the same wavelength; for example, on the basis of high-frequency signals of 10Gbps or 25Gbps and the like, a low-frequency signal of 50Kbps is added; high-frequency signals such as 10Gbps or 25Gbps are normal service signals, and the other path of low-frequency signals of 50Kbps are added to perform other functions while normal services are not occupied. For a transmitting end of an optical module, a dual-frequency optical signal needs to be sent out; for a receiving end of an optical module, it is necessary to receive a dual-frequency optical signal, and then demodulate signals of different frequencies in the optical signal respectively, so as to obtain a high-frequency signal and a low-frequency signal respectively.

The receiving end of the optical module comprises an optical receiving chip, a transimpedance amplifier chip TIA, an amplitude limiting amplifier chip LA, a first low-pass filter circuit, a second low-pass filter circuit, a comparison circuit and a microprocessor. The chip is essentially the integration of circuits, the circuits can be integrated into the chip, and part of functions in the chip can also be realized by the circuits on the circuit board. The functions of the chip can be realized by the chip, the circuit or the main chip combined with the peripheral circuit. Different functions can be integrated by the same chip, and the change of the circuit integration form still belongs to the protection scope of the invention.

Specifically, in an embodiment provided by the present invention, the light receiving chip, the amplitude limiting amplifier chip, the first low-pass filter circuit, the second low-pass filter circuit, the comparison circuit, and the microprocessor in the optical module are disposed on the surface of the circuit board, and since the area of the circuit board is limited, the circuits and the microprocessor are disposed on the same side surface of the circuit board according to layout requirements, and may be distributed on different side surfaces of the circuit board.

The electrical signal is processed by adopting the circuit, and because the electrical signal from the light receiving chip or the electrical signal from the mirror image circuit is generally small, an amplifying circuit is usually added in the circuit to improve the signal intensity.

Specifically, according to different packaging forms of the optical module, a light receiving chip of the optical module may be independently disposed in a coaxial package, the amplitude limiting amplification chip is preferably packaged in the coaxial package with the light receiving chip, the low-pass amplification circuit, the second low-pass filter circuit, the comparison circuit and the microprocessor are disposed on the surface of the circuit board, the coaxial package is electrically connected to the circuit board, and the specific electrical connection mode may be a flexible circuit board.

The nature of the chip is the integration of the circuit, and the specific form change of the circuit does not affect the protection scope of the embodiment of the present invention, which is exemplified by a specific product scheme.

Fig. 5 is a schematic diagram of an exploded structure of a receiving end (local) of an optical module according to an embodiment of the present invention. As shown in fig. 5, the optical module provided in the embodiment of the present invention includes a circuit board 300 and an optical receiving end 400. The light receiving end 400 is disposed on the surface of the circuit board 300, the light receiving end 400 includes a light receiving chip 401, an optical waveguide 402, a cover plate 403, a transimpedance amplifier chip 500, and an amplitude limiting amplifier chip 600, and the surface of the circuit board 300 has a gold finger 303.

The light receiving chip, the transimpedance amplification chip and the amplitude limiting amplification chip are respectively arranged on the surface of the circuit board and electrically connected with the circuit board; the cover plate 403 covers the light receiving chip, the transimpedance amplification chip, the amplitude limiting amplification chip, and the optical waveguide on the surface of the circuit board.

Fig. 6 is a partially enlarged view of a region a in fig. 5, where the region a includes an optical waveguide 402, a light receiving chip 401, and a transimpedance amplifier chip 500. As shown in fig. 6, the light receiving chip 401 is disposed on the surface of the circuit board 300, the optical waveguide 402 is located above the light receiving chip 401, the photosensitive surface of the light receiving chip 401 faces the optical waveguide 402, and light carrying mixed frequency signals is transmitted into the light receiving chip 401 through the optical waveguide 402, specifically, the end surface of the optical waveguide 402 is an inclined surface, and the light is reflected at the inclined surface of the optical waveguide 402 and then enters the photosensitive surface of the light receiving chip.

The light receiving chip is a chip used for receiving light signals at the receiving end of the optical module, light carrying a dual-frequency mixed signal is emitted into a photosensitive surface of the light receiving chip, the light receiving chip generates a current signal by utilizing a photoelectric conversion effect, the mixed frequency signal is carried by the current, and a carrier of the signal is changed but information is not changed in the process of converting the light into the current. The signal output by the light receiving chip is usually an analog signal, and the common light receiving chip is a PIN photodiode or a photo avalanche diode APD.

The first mixed frequency electrical signal (specifically, photocurrent) generated by the light receiving chip is transmitted to the transimpedance amplification chip, the photocurrent generated by the light receiving chip includes two parts, namely, a high-frequency signal and a low-frequency signal, and the photocurrent needs to be divided into at least two parts in order to respectively receive the high-frequency signal and the low-frequency signal. Generally, a mirror circuit is adopted to mirror the photocurrent, and the current generated after mirroring can be one path or two or more paths according to the subsequent signal processing requirements.

Specifically, when the light receiving chip adopts a PIN photodiode scheme, the transimpedance amplification chip matched with the PIN photodiode has a current output terminal 501 and optical voltage output terminals (502, 503), and the current output terminal 501 outputs the same current as the light receiving chip for subsequent low-frequency signal reception; the photovoltage output terminals (502, 503) output photovoltage converted from photocurrent.

Specifically, the amplitude limiting amplification chip is provided with a first mirror image circuit, the photocurrent from the light receiving chip is mirrored, and the mirrored current is output through a current output end, so that a third mixed frequency electric signal is output for subsequent low-frequency signal receiving; the photocurrent from the light receiving chip is used for subsequent high-frequency signal reception. The photocurrent from the light receiving chip is the most original current and is preferentially used for demodulation of the high-frequency signal to ensure the quality of service data, but theoretically, since the mirrored current is the same as the photocurrent, the mirrored current may also be used for receiving the high-frequency signal, and the photocurrent may be used for receiving the low-frequency signal. The transimpedance amplification chip may also integrate a conversion circuit to convert a current for low frequency signal reception into a voltage signal.

Specifically, a first mirror circuit in the optical module may mirror two paths of mirror currents, one path is used for demodulating a low-frequency or high-frequency signal, and the other path is used for detecting the received optical power intensity. The received light power strength RSSI detection circuit generally consists of a grounding resistor and a microprocessor, wherein the other path of mirror current is converted into a voltage signal through the grounding resistor and then is input into the microprocessor, and the microprocessor samples the voltage signal to obtain a received light power strength signal.

Specifically, the first mirror image circuit may be disposed in the transimpedance amplifier chip, or may be disposed on the circuit board outside the transimpedance amplifier chip. The mirror current can be directly output by the mirror circuit; or the current output end of the transimpedance amplification chip outputs the current.

The photocurrent signal enters the transimpedance amplification chip and is amplified and converted into a voltage signal, the voltage signal is output from the transimpedance amplification chip, the output of a second mixed frequency electric signal is achieved, the second mixed frequency electric signal is preferably output in a differential voltage signal form, and two output ports (502 and 503) are needed.

Specifically, when the light receiving chip adopts the APD photo avalanche diode scheme, the transimpedance amplification chip matched to the APD photo avalanche diode has a photo voltage output terminal (502, 503), and the photo voltage output terminal (502, 503) outputs a photo voltage converted from a photo current, preferably in a differential form.

Specifically, because the voltage required by the APD avalanche photodiode during operation is higher than the voltage required by the optical module during normal operation, a voltage boost circuit is added in the optical module and is used for providing high operating voltage for the APD; in order to receive photocurrent, a second mirror image circuit is added in the optical module, the booster circuit is connected with the APD through a path in the mirror image circuit, the current in the path is the photocurrent generated by the APD, and the current in the path is used for receiving high-frequency signals subsequently; the second mirror image circuit mirrors the current in the path to obtain a mirror image current of the photocurrent, and the third mixed frequency electric signal is specifically expressed as the mirror image current; the mirror current is used for subsequent reception of low frequency signals. The photocurrent from the light receiving chip is the most original current and is preferentially used for demodulation of the high-frequency signal to ensure the quality of service data, but theoretically, since the mirrored current is the same as the original current, the mirrored current may be used for receiving the high-frequency signal, and the original current may be used for receiving the low-frequency signal. A conversion circuit may also be integrated in the second mirror circuit to convert the current for low frequency signal reception into a voltage signal.

Specifically, a second mirror circuit in the optical module may mirror two paths of mirror currents, where one path is used for demodulating a low-frequency or high-frequency signal, and the other path is used for detecting the received optical power intensity. The received light power strength RSSI detection circuit generally consists of a grounding resistor and a microprocessor, wherein the other path of mirror current is converted into a voltage signal through the grounding resistor and then is input into the microprocessor, and the microprocessor samples the voltage signal to obtain a received light power strength signal.

Specifically, the boost circuit may be disposed in the transimpedance amplifier chip, or on the circuit board, and may be in the form of a chip, or a circuit, or a main chip combined with a peripheral circuit;

specifically, the second mirror image circuit may be disposed in the transimpedance amplifier chip, or on the circuit board, and may be in the form of a chip, or a circuit, or a combination of a main chip and a peripheral circuit.

The photocurrent signal enters the transimpedance amplification chip and is amplified and converted into a voltage signal, the voltage signal is output from the transimpedance amplification chip, the output of a second mixed frequency electric signal is achieved, and the voltage signal is preferably output in a differential mode.

Fig. 7 is a partially enlarged view of the area B in fig. 5. As shown in fig. 7, in the optical module according to the embodiment of the present invention, an amplitude limiting amplifier chip 600 is disposed on the circuit board 300, and the amplitude limiting amplifier chip is connected to the transimpedance amplifier chip and configured to receive an optical voltage signal. The amplitude limiting amplification chip further amplifies the optical voltage signal and limits the optical voltage signal in a set output differential amplitude, and the voltage signal output from the amplitude limiting amplification chip is a high-frequency signal. The limiting amplification chip is provided with input ports (601, 602) for receiving optical voltage signals (optical voltage signals in a differential form) from the transimpedance amplification chip, and is provided with output ports (603, 604) for outputting high-frequency signals. The gold finger on the circuit board 300 has

pins

605, 606, and the high frequency signal is output to the upper computer through the

pins

605, 606. On both sides of the

pins

606, 606 transmitting high frequency signals, there are

ground pins

607, 608 for achieving electrical isolation of the pins transmitting high frequency signals.

And a capacitor is connected between the amplitude limiting amplification chip and the transimpedance amplification chip. Specifically, the transimpedance amplification chip outputs two paths of differential signals, the first capacitor connects one path of the differential signals to a first input end of the amplitude limiting amplification chip, and the second capacitor connects the other path of the differential signals to a second input end of the amplitude limiting amplification chip; the amplitude limiting amplification chip is combined with the first capacitor and the second capacitor, and high-pass filtering is carried out on the voltage signal output by the trans-impedance amplification chip so as to output a high-frequency signal.

In addition, in practical applications, the design of the limiting amplification chip is generally directed to high-frequency electrical signals, because the optical fiber communication service is signal transmission with high speed and ultrahigh speed, the limiting amplification chip cannot simultaneously receive mixed frequency signals with such a large frequency difference, and the limiting amplification chip generally only recognizes a high-frequency part in the electrical signals.

Specifically, the first capacitor, the second capacitor and a pull-up resistor integrated in the amplitude limiting amplification chip form a high-pass filter, and when a voltage signal passes through the first capacitor, the second capacitor and the amplitude limiting amplification chip, a low-frequency signal in the voltage signal is filtered, so that high-pass filtering is realized.

Fig. 8 is another schematic structural diagram of an optical module according to an embodiment of the present invention, and fig. 9 is a circuit connection diagram of the optical module shown in fig. 8. Fig. 5 shows one side surface of the circuit board, and fig. 8 shows the other side surface of the circuit board, and since the space on the surface of the circuit board is limited, the chips on the circuit board are respectively disposed on the upper and lower surfaces of the circuit board. Fig. 8 shows the position of a part of the circuit/chip on the optical module circuit board, which specifically includes a low-pass amplifying circuit 700, a second low-pass filtering circuit 800, a comparing circuit 900 and a microprocessor 304. Electrical connections between the circuits/chips of fig. 8 other than the microprocessor are shown in fig. 9. As shown in fig. 8, the low-pass amplifying circuit 700, the second low-pass filtering circuit 800, the comparing circuit 900 and the microprocessor 304 are disposed on the surface of the circuit board, the low-pass amplifying circuit 700 is connected to the second low-pass filtering circuit 800 and the comparing circuit 900 respectively, the second low-pass filtering circuit is connected to the comparing circuit 900, and the comparing circuit is connected to the microprocessor 304.

The current or voltage for receiving the low-frequency signal is connected into the low-pass amplifying circuit. The low-pass amplifier circuit is exemplified by a main chip combined with a peripheral circuit, and the low-frequency signal is exemplified by a current signal.

The filter circuit generally comprises a reactive element, such as a capacitor C connected in parallel across a load resistor or an inductor L connected in series with the load, and various complex filter circuits comprising capacitors and inductors. Commonly used filter circuits are of two broad classes, passive and active. If the filter circuit element is composed of only passive elements (resistors, capacitors, inductors), the filter circuit element is called a passive filter circuit. The main forms of passive filtering are capacitive filtering, inductive filtering and complex filtering (including inverted-L filtering, LC pi-type filtering, RC pi-type filtering and the like). A filter circuit is called an active filter circuit if it is composed of not only passive elements but also active elements (bipolar type tubes, unipolar type tubes, integrated operational amplifiers). The main form of active filtering is active RC filtering, also called electronic filter.

Fig. 10 is a schematic diagram of a related circuit structure of a low-pass amplifying circuit according to an embodiment of the present invention. As shown in fig. 10, the current for receiving the low frequency signal is connected to one end of the resistor R2, the other end of the resistor R2 is grounded, one end of the ground resistor R2 is further connected to the low pass amplifier circuit, and the current is converted into a voltage by the grounded resistor R2 and then input to the low pass amplifier circuit. The low-pass amplifying circuit comprises an operational amplification main chip 701, peripheral resistors R4 and R5 and a peripheral capacitor C3, wherein the operational amplification main chip is combined with the resistor R4 and the resistor R5 to form a filtering amplifying circuit, specifically, one end of the resistor R4 is grounded, and the other end of the resistor R4 is connected to an input pin IN & lt- & gt of the operational amplification main chip; one end of the resistor R5 is connected with an input pin IN of the operational amplification main chip, and the other end is connected with an output pin OUT of the operational amplification main chip; IN order to adjust the range of the cut-off frequency of the filter amplifying circuit, a capacitor C3 is added, one end of the capacitor C3 is connected to an input pin IN of the operational amplification main chip, and the other end of the capacitor C3 is connected to an output pin OUT of the operational amplification main chip. The operational amplification main chip also comprises a power supply pin V +, a power supply pin V-and an enable pin SD; the power supply pin is used for supplying power to the operational amplification main chip, and the enabling pin is a switch pin of the operational amplification main chip.

The low-pass amplification circuit amplifies the received voltage signal and filters out its high-frequency signal portion, leaving only the amplified low-frequency signal portion.

FIG. 11 is a schematic diagram of voltage signal conversion implemented by the circuit of FIG. 10. As shown in fig. 11, the voltage signal connected to the low-pass amplifying circuit is an analog signal, and includes a dc component a and an ac component b, the dc component has different intensities, including two voltage amplitudes, e and f, when the dc intensity of the voltage signal is large, and the voltage signal is amplified by the low-pass amplifying circuit, the voltage signal will exceed the upper limit of the low-pass amplifying circuit, in order to avoid this, a capacitor C1 is disposed before the voltage signal is output to the low-pass amplifying circuit, the capacitor C1 filters the dc, and only the ac component is retained; in order to obtain a voltage signal with sufficient strength after passing through the low-pass amplifying circuit, a direct-current output power source VREF is connected between the capacitor C1 and the low-pass amplifying circuit, and a uniform direct current is provided for the voltage signal after the direct current is filtered out, so that the voltage amplitude C is obtained. The direct current with non-uniform intensity is filtered by the capacitor C1, and then the direct current with uniform intensity is provided by the power supply VREF, so that a better signal source is provided for the low-pass amplification circuit, and the signal quality after low-pass amplification is ensured.

The signal output by the low-pass amplifying circuit is divided into two identical paths, namely a first low-frequency electric signal and a second low-frequency electric signal, the first low-frequency electric signal enters a second low-pass filter circuit, and the second low-frequency electric signal enters a first input end of a comparison circuit.

Fig. 12 is a schematic structural diagram of a second low-pass filter circuit according to an embodiment of the present invention. As shown in fig. 12, the second low-pass filter circuit includes a peripheral resistor R6 and a peripheral capacitor C5, which form a typical RC filter circuit in electronics, specifically, one end of a resistor R6 is connected to a signal, the other end of the resistor R6 is connected to one end of a capacitor C5, the other end of the capacitor C5 is grounded, and one end of a capacitor C5 outputs the filtered signal. By adjusting the resistance of the resistor R6 and the capacitance of the capacitor C5, the cut-off frequency of the filter circuit can be adjusted, and the filter range of the filter circuit can be controlled. Specifically, the resistor R6 may be replaced by an inductor.

The rear end of the RC type filter circuit can be connected with the operation main chip 801, the resistor R8 and the capacitor C6 to form an isolation circuit with high input resistance and low output resistance, so that influence of loads such as a subsequent comparison circuit on the filter characteristic of the second low-pass filter circuit is avoided.

Fig. 13 is a schematic diagram of voltage signal conversion implemented by the circuit of fig. 12. As shown in fig. 13, the second low-pass filter circuit receives the second output signal from the low-pass amplification circuit. The second output signal is processed by a low-pass filter, and high frequency is further filtered to obtain a decision threshold electrical signal for generating a subsequent digital signal, wherein the decision threshold electrical signal can be a direct current signal. The decision threshold electrical signal is input to a second input terminal of the comparison circuit.

The low-pass amplifying circuit and the second low-pass filtering circuit are both circuits for filtering high-frequency signals, only the high-frequency frequencies set by the low-pass amplifying circuit and the second low-pass filtering circuit are different, and the filtering frequency is set by setting the RC parameters of the resistor and the capacitor in the circuits. Taking the mixing of the 10Gbps high-frequency signal and the 50Kbps low-frequency signal as an example, the low-pass amplifying circuit can filter the 10Gbps high-frequency signal and only reserve the 50Kbps low-frequency signal; compared with the setting parameters of the second low-pass filter circuit, the 50Kbps is still a high-frequency signal, and the second low-pass filter circuit can filter the 50Kbps frequency signal, so that a direct-current signal with lower frequency is obtained.

Fig. 14 is a schematic diagram of a comparison circuit structure according to an embodiment of the present invention. As shown IN fig. 14, the first input terminal IN + of the comparison circuit receives the first signal from the low-pass amplifying circuit, the second input terminal IN-receives the dc signal from the second low-pass filtering circuit, the comparison current compares the signal at the first input terminal with the signal at the second input terminal, and the output terminal OUT outputs the third low-frequency electrical signal. The comparator can also comprise a power supply pin V +, a power supply pin V-and an enable pin SD; the power pin is used for supplying power, and the enabling pin is a switch pin.

Fig. 15 is a schematic diagram of voltage signal conversion of the comparison circuit in fig. 14. As shown in fig. 15, the low frequency signal receiving pin of the microprocessor is used for receiving a low frequency signal of the dual frequency signals, the microprocessor is connected to the output terminal of the comparing circuit, and the third low frequency electrical signal may be a digital signal in order to increase the signal processing speed of the microprocessor.

The received optical power strength detection pin of the microprocessor is used for receiving the optical voltage generated by the mirror image optical current to generate a received optical power strength signal. The received optical power intensity is one of the working indexes of the optical module which is required to be monitored in the industry standard, the optical module is required to be automatically collected and stored, and the received optical power intensity is read from the optical module when the upper computer is required. The received light power intensity is derived from the photocurrent intensity generated by the light receiving chip, and is collected, calculated and stored by a microprocessor MCU of the optical module.

Claims

1. An optical module is characterized by comprising an optical receiving chip, a transimpedance amplification chip, an amplitude limiting amplification chip, a first low-pass filter circuit, a second low-pass filter circuit, a comparison circuit and a microprocessor;

the transimpedance amplification chip is electrically connected with the light receiving chip, the amplitude limiting amplification chip and the first low-pass filter circuit respectively;

the optical receiving chip outputs a first mixed frequency electric signal to the transimpedance amplification chip;

the transimpedance amplification chip outputs a second mixed frequency electric signal to the amplitude limiting amplification chip;

the amplitude limiting amplification chip outputs a high-frequency electric signal;

the transimpedance amplification chip outputs a third mixed frequency electric signal to the first low-pass filter circuit; the third mixed frequency electrical signal is a mirror image signal of the first mixed frequency electrical signal;

the second low-pass filter circuit is electrically connected with the first low-pass filter circuit, and the first low-pass filter circuit outputs a first low-frequency electric signal to the second low-pass filter circuit;

the first input end of the comparison circuit is electrically connected with the first low-pass filter circuit, the second input end of the comparison circuit is electrically connected with the second low-pass filter circuit, the output end of the comparison circuit is connected with the microprocessor,

the first low-pass filter circuit inputs a second low-frequency electric signal to the comparison circuit;

the second low-pass filter circuit inputs a decision threshold electric signal to the comparison circuit;

the comparison circuit outputs a third low frequency electrical signal to the microprocessor.

2. The optical module according to claim 1, further comprising a circuit board, wherein the light receiving chip, the transimpedance amplification chip, the amplitude limiting amplification chip, the first low-pass filter circuit, the second low-pass filter circuit, the comparison circuit, and the microprocessor are respectively disposed on the circuit board.

3. The optical module of claim 1, further comprising a circuit board and a separate package;

the independent packaging body is electrically connected with the circuit board;

the amplitude limiting amplification chip, the first low-pass filter circuit, the second low-pass filter circuit, the comparison circuit and the microprocessor are respectively arranged on the circuit board;

the light receiving chip and the transimpedance amplification chip are respectively arranged in the independent packaging body.

4. The optical module according to claim 1, wherein a capacitor and a dc output power supply are connected between the limiting amplifier chip and the first low pass filter circuit.

5. The optical module of claim 1, wherein an isolation circuit is interposed between the second filter circuit and the comparison circuit.

6. An optical module is characterized by comprising an optical receiving chip, a boost mirror image circuit, a transimpedance amplification chip, an amplitude limiting amplification chip, a first low-pass filter circuit, a second low-pass filter circuit, a comparison circuit and a microprocessor;

the transimpedance amplification chip is electrically connected with the light receiving chip and the amplitude limiting amplification chip respectively;

the transimpedance amplification chip outputs a second mixed frequency electric signal to the amplitude limiting amplification chip, and the amplitude limiting amplification chip outputs a high-frequency electric signal;

the boosting mirror circuit is electrically connected with the light receiving chip and the first low-pass filter circuit respectively; the boosting mirror circuit outputs working high voltage to the light receiving chip; the boosting mirror image circuit outputs a mirror image electric signal of the first mixed frequency electric signal to the first low-pass filter circuit;

the first input end of the comparison circuit is electrically connected with the first low-pass filter circuit, the second input end of the comparison circuit is electrically connected with the second low-pass filter circuit, and the output end of the comparison circuit is connected with the microprocessor; the first low-pass filter circuit inputs a second low-frequency electric signal to the comparison circuit;

7. The optical module according to claim 6, further comprising a circuit board, wherein the light receiving chip, the boost mirror circuit, the transimpedance amplifier chip, the limiting amplifier chip, the first low-pass filter circuit, the second low-pass filter circuit, the comparison circuit, and the microprocessor are respectively disposed on the circuit board.

8. The optical module of claim 6, further comprising a circuit board and a separate package;

the light receiving chip, the boost mirror circuit and the transimpedance amplifier chip are respectively arranged in the independent packaging body.

9. The optical module according to claim 6, wherein a capacitor and a dc output power supply are connected between the boost mirror circuit and the first low pass filter circuit.

10. The optical module of claim 6, wherein an isolation circuit is interposed between the second filter circuit and the comparison circuit.