CN110190904B

CN110190904B - Method and device for realizing optical modulation signal in WDM PON system

Info

Publication number: CN110190904B
Application number: CN201910412500.9A
Authority: CN
Inventors: 刘新峰; 刘建桥; 王志军
Original assignee: Fiberhome Telecommunication Technologies Co Ltd
Current assignee: Fiberhome Telecommunication Technologies Co Ltd
Priority date: 2019-05-17
Filing date: 2019-05-17
Publication date: 2021-03-16
Anticipated expiration: 2039-05-17
Also published as: CN110190904A

Abstract

The invention discloses a method and a device for realizing optical modulation and demodulation signals in a WDM PON system, and relates to the field of optical communication. The method comprises the following steps: carrying out code modulation on the low-speed management data to obtain low-speed management code modulation data; coupling the low-speed management coding modulation data with a current signal to generate a low-speed intensity modulation current signal; the optical amplifier with the low-speed modulation characteristic modulates the intensity of a low-speed intensity modulation current signal onto a high-speed optical channel by using the intensity change of the modulation current to generate an optical modulation and demodulation signal and amplifies a high-speed service data optical signal. The invention can realize the modulation of the low-speed management signal to the high-speed optical channel.

Description

Method and device for realizing optical modulation signal in WDM PON system

Technical Field

The invention relates to the field of optical communication, in particular to a method and a device for realizing optical modulation and demodulation signals in a WDM PON system.

Background

With the development of 5G communication technology, large bandwidth, low delay and the like become important index parameters of 5G communication, and a WDM PON (Wavelength Division Multiplexing PON) system with virtual point-to-point connection has unique advantages in terms of bandwidth and delay, and will be an important solution for 5G fronthaul.

The WDM PON technology is used in a commercial scale, and the key technology lies in the implementation of a colorless ONU (Optical Network Unit), and the colorless ONU needs to solve the functions of wavelength adjustability, channel monitoring, real-time management, and the like. The laser can convert 25G of high-speed service data electrical signals into high-speed service data optical signals, and because the rate of the electrical signals is high, the low-speed management data is not coupled with the high-speed signals to be sent out through the laser, so that the electrical domain of the high-speed signals is not affected. Therefore, an Optical Top Adjustment (Optical Top Adjustment) technology is required to modulate a low-speed management signal onto a high-speed Optical channel, so as to more conveniently monitor the wavelength, the connection state, and the signal quality of each channel in real time, and more conveniently manage and adjust each channel in real time.

In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:

the 25G high-speed service data electrical signal is directly coupled with the low-speed electrical domain signal, and the problems that the integrity of the high-speed signal is difficult to solve, the technical scheme is complex, and high-speed board distribution is needed exist, so that the development period is long, the production test is tedious, the product yield is low, and the cost of the electrical domain direct coupling is very high. How to use a low-cost practical method to implement an optical modulation and demodulation technology to modulate a low-speed management signal onto a high-speed optical channel is an important technical problem to be solved urgently in the field.

Disclosure of Invention

The present invention is directed to overcome the above-mentioned drawbacks of the prior art, and provides a method and an apparatus for implementing an optical modulation signal in a WDM PON system, which can implement modulation of a low-speed management signal onto a high-speed optical channel.

In a first aspect, a method for implementing an optical pilot tone signal in a WDM PON system is provided, which includes the following steps:

carrying out code modulation on the low-speed management data to obtain low-speed management code modulation data;

coupling the low-speed management coding modulation data with a current signal to generate a low-speed intensity modulation current signal;

the optical amplifier with the low-speed modulation characteristic modulates the intensity of a low-speed intensity modulation current signal onto a high-speed optical channel by using the intensity change of modulation current to generate an optical modulation top signal and amplifies the optical modulation top signal and a high-speed service data optical signal.

According to the first aspect, in a first possible implementation manner of the first aspect, the method further includes the following steps:

at a sending end of the ONU, the high-speed service data electrical signal and the threshold current are respectively sent to the laser and the high-speed component, the threshold current provides the working current required by the laser, and the high-speed service data electrical signal is converted into a high-speed service data optical signal by the laser.

According to the first aspect, in a second possible implementation manner of the first aspect, the optical amplifier with the low-speed modulation characteristic is an SOA or an EDFA.

In a third possible implementation manner of the first aspect, the optical amplifier with the low-speed modulation characteristic is integrated with the laser and the high-speed component, or is externally arranged separately.

In a second aspect, an apparatus for implementing an optical pilot signal in a WDM PON system is provided, comprising:

a control management unit to: outputting low-speed management data and a current signal;

a modulation unit to: carrying out code modulation on the low-speed management data to obtain low-speed management code modulation data;

a coupling circuit to: coupling the low-speed management coding modulation data with a current signal to generate a low-speed intensity modulation current signal;

an optical amplifier having a low speed modulation characteristic for: modulating the intensity characteristic of a low-speed intensity modulation current signal to a high-speed optical channel by using the intensity change of modulation current to generate a light modulation and demodulation signal and amplifying a high-speed service data optical signal;

laser and high-speed components: for converting the high speed service data electrical signal into a high speed service data optical signal.

According to the second aspect, in a first possible implementation manner of the second aspect, the control management unit sends the low-speed management data to the modulation unit through the low-speed data interface, and the control management unit further outputs the current signal to the coupling circuit through the DAC converter.

According to the second aspect, in a second possible implementation manner of the second aspect, the optical amplifier with the low-speed modulation characteristic is an SOA or an EDFA.

According to the second aspect, in a third possible implementation manner of the second aspect, the optical amplifier with the low-speed modulation characteristic is integrated with the laser and the high-speed component, or is externally arranged separately.

According to the second aspect, in a fourth possible implementation manner of the second aspect, the modulation unit is specifically configured to: at a transmitting end, low-speed management data is coded, then a digital signal is converted into an analog signal, and the analog signal is output to a coupling circuit through an output pin of a modulation unit.

According to the second aspect, in a fifth possible implementation manner of the second aspect, the coupling circuit includes a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, a transistor T1, a fourth resistor R4, and a second capacitor C2, one end of the first capacitor C1 is connected to the output of the modulation unit, the other end of the first capacitor C1 is connected to one end of the first resistor R1, one end of the second resistor R2, and one end of the third resistor R3, the other end of the first resistor R1 is connected to a power supply, the other end of the second resistor R2 is connected to a ground, the other end of the third resistor R3 is connected to a base of the transistor T1, an emitter of the transistor T1 is connected to a ground, a collector of the transistor T1 is connected to a current source through the fourth resistor R4, and a collector of the transistor T1 is further connected to a second capacitor C2.

Compared with the prior art, the invention has the following advantages:

(1) the optical amplifier with the low-speed modulation characteristic modulates the intensity characteristic of a low-speed intensity modulation current signal onto a high-speed optical channel by using the intensity change of the modulation current to generate an optical modulation top signal and amplifies the optical modulation top signal and the high-speed service data optical signal. The Optical Amplifier with the low-speed modulation characteristic is an SOA (Semiconductor Amplifier) or an EDFA (Erbium-Doped Fiber Amplifier), the SOA or the EDFA has a re-modulation function while amplifying, uplink data can be modulated, low-speed management signals can be modulated onto a high-speed Optical channel, Optical power can be amplified simultaneously, the transmission distance is effectively prolonged, and the problems that high-speed signal integrity is difficult to solve, the technical scheme is complex, high-speed layout is needed and the like due to direct coupling of the low-speed signals and the high-speed signals in an electric domain are solved.

(2) The SOA or EDFA has no selectivity to wavelength, so that the number of users accessing the ONU can be increased.

(3) And the remodulation is carried out on the SOA or the EDFA, and only a small amount of electric devices are added, so that the cost can be effectively reduced.

(4) The optical amplifier with the low-speed modulation characteristic can be integrated with the laser and the high-speed component, can also be externally arranged in a separated mode, and can be flexibly configured and optimized in cost.

Drawings

FIG. 1 is an architecture diagram of a WDM PON system;

fig. 2 is a flowchart of a method for implementing an optical pilot tone signal in a WDM PON system according to an embodiment of the present invention;

fig. 3 is a block diagram of an apparatus for implementing an optical pilot tone in a WDM PON system according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of modulated current signal generation in an embodiment of the present invention;

FIG. 5 is a functional block diagram of low speed management data modulation in an embodiment of the present invention;

fig. 6 is a functional block diagram of a coupling circuit in an embodiment of the invention.

Detailed Description

Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the specific embodiments, it will be understood that they are not intended to limit the invention to the embodiments described. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. It should be noted that the method steps described herein may be implemented by any functional block or functional arrangement, and that any functional block or functional arrangement may be implemented as a physical entity or a logical entity, or a combination of both.

In order that those skilled in the art will better understand the present invention, the following detailed description of the invention is provided in conjunction with the accompanying drawings and the detailed description of the invention.

Note that: the example to be described next is only a specific example, and does not limit the embodiments of the present invention necessarily to the following specific steps, values, conditions, data, orders, and the like. Those skilled in the art can, upon reading this specification, utilize the concepts of the present invention to construct more embodiments than those specifically described herein.

Fig. 1 is a WDM PON system architecture diagram. Referring to fig. 1, the WDM PON system includes an optical Line terminal OLT (optical Line termination), an optical Network unit ONU (optical Network unit), and an optical Distribution Network ODN (optical Distribution Network), where the OLT includes an LD (Laser Diode), a PD (Photo Diode), an AWG (Arrayed Waveguide Grating), and the ODN is an optical Network located between the OLT and the ONU and implementing wavelength allocation from the OLT to the ONU or from the ONU to the OLT. The ODN mainly includes AAWG (thermally insensitive Arrayed Waveguide Grating), which is a wavelength sensitive passive optical device and performs optical wavelength multiplexing and demultiplexing functions. The WDM PON realizes point-to-multipoint connection based on a wavelength division multiplexing mode, the wavelength is used as an identification of the user side ONU, and each user effectively improves the user bandwidth through different independent bandwidths of the wavelength.

In a WDM PON, a colorless ONU is a system key, and the realization of the colorless ONU technology requires that an ONU-side optical module has an adjustable and controllable wavelength, the ONU is convenient to manage, and a management signal is easy to transmit on an optical path.

Referring to fig. 2, an embodiment of the present invention provides a method for implementing an optical modulation and demodulation signal in a WDM PON system, including the following steps:

s1, carrying out coding modulation on the low-speed management data to obtain low-speed management coding modulation data;

s2, coupling the low-speed management coding modulation data with the current signal to generate a low-speed intensity modulation current signal;

and S3, the optical amplifier with the low-speed modulation characteristic modulates the intensity of the low-speed intensity modulation current signal to the high-speed optical channel by using the intensity change of the modulation current, generates an optical pilot tone signal, and amplifies the optical pilot tone signal and the high-speed service data optical signal.

As a preferred embodiment, the above method further comprises the steps of:

at a sending end of the ONU, the high-speed service data electrical signal is coupled with a threshold current and then enters the laser and the high-speed assembly, the threshold current provides a working current required by the laser, and the high-speed service data electrical signal is converted into a high-speed service data optical signal by the laser.

As a preferred embodiment, the above method further comprises the steps of:

the optical amplifier having the low-speed modulation characteristic is an SOA or EDFA.

The SOA or EDFA has the performance of amplification and remodulation, can modulate management data to an optical channel, and simultaneously amplifies the management data, thereby being beneficial to transmission.

In a high-speed WDM PON system, optical signals are often amplified by using an SOA (semiconductor amplifier) or EDFA (erbium-doped fiber amplifier), and the like, and in the embodiment of the invention, on the basis of an SOA or EDFA device, low-speed management data is modulated onto a high-speed optical channel by using the modulation characteristic of the SOA or EDFA to obtain an optical modulation and demodulation signal of the low-speed management data, and then the optical modulation and demodulation signal and the high-speed service data optical signal are amplified by using the amplification function of the SOA or EDFA, so that the transmission distance can be effectively extended and transmitted to an opposite-end OLT device, and monitoring and management of the high-speed optical channel are realized.

The optical amplifier with the low-speed modulation characteristic can be integrated with the laser and the high-speed component, can also be externally arranged in a separated mode, and can be flexibly configured and optimized in cost.

Referring to fig. 3, an embodiment of the present invention further provides an apparatus for implementing an optical modulation signal in a WDM PON system, including:

a control management unit to: outputting low-speed management data and current signals to realize control and management functions;

laser and high-speed components: the optical signal processing device is used for converting the high-speed service data electrical signal into a high-speed service data optical signal;

an optical amplifier having a low speed modulation characteristic for: and modulating the intensity of the low-speed intensity modulation current signal to a high-speed optical channel by using the intensity change of the modulation current to generate an optical modulation top signal and amplify the optical modulation top signal and the high-speed service data optical signal.

As a preferred embodiment, the control management unit sends low-speed management data to the modulation unit through the low-speed data interface, and outputs a current signal to the coupling circuit through the DAC converter.

In a preferred embodiment, the optical amplifier with low-speed modulation characteristic is an SOA or an EDFA.

The SOA or EDFA can directly amplify optical signals in an optical domain without traditional optical-electrical-optical conversion, so that the limitation of optical signal loss on transmission distance is solved, and the cost of system equipment is reduced.

The SOA or EDFA belongs to a current device, has a modulation characteristic, and can be modulated by the intensity change of current.

As a preferred embodiment, the optical amplifier with low-speed modulation characteristic may be integrated with the laser and the high-speed component, or may be separately external, and may be flexibly configured to optimize the cost.

The SOA or EDFA in the embodiment of the invention is used for amplifying the optical signal and modulating the low-speed management data to the high-speed optical channel.

As a preferred embodiment, the modulation unit is specifically configured to: at a sending end, the low-speed management data is coded, then a sending module is used for converting a digital signal into an analog signal, and an output pin of a modulation unit outputs the analog signal to a coupling circuit.

Referring to fig. 3, at a transmitting end of the ONU, the high-speed service data electrical signal is coupled to a threshold current and sent to the laser and the high-speed component, the threshold current provides a working current required by the laser, and the high-speed service data electrical signal is converted into an optical signal by the laser. Because the device for realizing the optical modulation signal in the WDM PON system has no direct relation with the light-emitting wavelength, the embodiment of the invention can be used for scenes with adjustable wavelength and scenes with fixed wavelength.

The power of light emitted by the laser and the high-speed component is relatively low, and in the process of transmitting the light to the OLT through a later optical path, the insertion loss of the wavelength division multiplexing/demultiplexing device exists, so that in order to compensate the insertion loss and prolong the transmission distance, an optical signal emitted by the laser is amplified through an SOA or EDFA.

The system integrates a high-performance control management unit, the control management unit can be an MCU, a DSP, an FPGA and the like, and fig. 4 and 5 are examples when the control management unit is an MCU. The control management unit can output a relatively accurate current signal, simultaneously sends low-speed management data to the modulation unit to generate low-speed management coding modulation data, then the low-speed management coding modulation data is coupled with the current signal to generate a modulation current signal, the modulation current signal is sent to the SOA or EDFA, an optical modulation and demodulation signal with coding characteristics is generated after modulation of the SOA or EDFA, and the optical modulation and demodulation signal and the optical signal of the high-speed service data are amplified and transmitted together.

Fig. 4 shows the modulation process of the low-speed management data electric signal, and the control management unit outputs two signals, one is to send the management data signal through the low-speed data interface, and the other is to output an accurate current signal through the DAC converter. The low-speed management data passes through the modulation unit, the low-speed management coded modulation data is generated through coding, then the low-speed management coded modulation data and the current signal pass through the coupling circuit, and a modulated current signal is generated, wherein the modulated current signal has the characteristic of intensity, and the intensity is consistent with the coding frequency of the low-speed management coded modulation data, so that the coded information can be modulated onto an optical channel of an SOA or an EDFA.

Fig. 5 is a schematic block diagram of low-speed management data modulation, and the modulation unit has small volume and high integration level, and meets the requirement of module miniaturization. The modulation unit includes a modulation and demodulation section having functions of buffering an output and shaping and filtering an input signal. The low-speed management data is a digital signal generated by the control management unit through the low-speed data interface and is sent to the modulation unit, the modulation unit encodes the management data, then the digital signal is converted into an analog signal through the sending module and is output by an output pin of the modulation unit, and then the output analog signal is sent to the coupling circuit. Meanwhile, at the receiving end, the modulation unit filters, shapes and decodes the received management information, and then sends the management data to the control management unit through a low-speed data interface.

Fig. 6 is a functional block diagram of a coupling circuit.

In a preferred embodiment, the coupling circuit includes a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, a transistor T1, a fourth resistor R4, and a second capacitor C2, one end of the first capacitor C1 is connected to the output of the modulation unit, the other end of the first capacitor C1 is connected to one end of the first resistor R1, one end of the second resistor R2, and one end of the third resistor R3, the other end of the first resistor R1 is connected to a power supply, the other end of the second resistor R2 is connected to a ground, the other end of the third resistor R3 is connected to the base of the transistor T1, the emitter of the transistor T1 is connected to a ground, the collector of the transistor T1 is connected to a current source through the fourth resistor R4, and the collector of the transistor T1 is further connected to the second capacitor C36.

Referring to fig. 6, C1 has the function of isolating the direct current and the direct current, so as to allow the encoded signal with frequency characteristic to pass through and isolate the direct current signal, thereby preventing the direct current level signal from affecting the output of the modulation unit.

R1 and R2 are DC offset resistors, and the required DC offset value is set according to the switching level of the triode T1 and the amplitude of the low-speed management code modulation signal.

R3 is a current limiting resistor, R4 is a bias resistor, and after the current source passes through R4, a voltage drop is generated across R4, and the voltage drop can provide a bias voltage for the collector of the transistor T1.

The current source is a direct current signal output by the control management unit.

The C2 is a blocking capacitor, the DC signal is modulated into an AC signal with the same intensity as the triode T1 by the on and off of the triode T1, and a current modulation signal is generated after passing through the C2 and then sent to an SOA or EDFA device.

Based on the same inventive concept, the embodiments of the present application further provide a computer-readable storage medium, on which a computer program is stored, and the computer program, when executed by a processor, implements all or part of the method steps of the above method.

The present invention can implement all or part of the processes of the above methods, and can also be implemented by using a computer program to instruct related hardware, where the computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above method embodiments can be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, recording medium, U-disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), random-Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution media, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, in accordance with legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunications signals.

Based on the same inventive concept, an embodiment of the present application further provides an electronic device, which includes a memory and a processor, where the memory stores a computer program running on the processor, and the processor executes the computer program to implement all or part of the method steps in the method.

The processor may be a Central Processing Unit (CP U), or may be other general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, or the like. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, the processor being the control center of the computer device and the various interfaces and lines connecting the various parts of the overall computer device.

The memory may be used to store computer programs and/or modules, and the processor may implement various functions of the computer device by executing or executing the computer programs and/or modules stored in the memory, as well as by invoking data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (e.g., a sound playing function, an image playing function, etc.); the storage data area may store data (e.g., audio data, video data, etc.) created according to the use of the cellular phone. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Memory Card (SMC), a Secure Digital (SD) Card, a flash memory Card (F lash Card), at least one magnetic disk storage device, a flash memory device, or other volatile solid state storage device.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, server, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), servers and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for realizing optical modulation signals in a WDM PON system is characterized by comprising the following steps:

the optical amplifier with the low-speed modulation characteristic modulates the intensity of a low-speed intensity modulation current signal onto a high-speed optical channel by using the intensity change of modulation current to generate an optical modulation top signal and amplifies the optical modulation top signal and a high-speed service data optical signal;

the optical amplifier with the low-speed modulation characteristic is an SOA or an EDFA;

the optical amplifier with the low-speed modulation characteristic is integrated with the laser and the high-speed component or is externally arranged in a separated mode.

2. The method of claim 1, wherein: further comprising the steps of:

3. An apparatus for implementing an optical pilot signal in a WDM PON system, comprising:

4. The apparatus of claim 3, wherein:

the control management unit sends low-speed management data to the modulation unit through the low-speed data interface, and the control management unit outputs current signals to the coupling circuit through the DAC.

5. The apparatus of claim 3, wherein:

the modulation unit is specifically configured to: at a transmitting end, low-speed management data is coded, then a digital signal is converted into an analog signal, and the analog signal is output to a coupling circuit through an output pin of a modulation unit.

6. The apparatus of claim 3, wherein: the coupling circuit comprises a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, a triode T1, a fourth resistor R4 and a second capacitor C2, wherein one end of the first capacitor C1 is connected with the output of the modulation unit, the other end of the first capacitor C1 is connected with one end of the first resistor R1, one end of the second resistor R2 and one end of the third resistor R3 respectively, the other end of the first resistor R1 is connected with a power supply, the other end of the second resistor R2 is grounded, the other end of the third resistor R3 is connected with the base of the triode T1, the emitter of the triode T1 is grounded, the collector of the triode T1 is connected with a current source through the fourth resistor R4, and the collector of the triode T1 is further connected with a second capacitor C2.