CN114650096A - Optical path self-adaptive dispersion compensation method, optical module and wavelength division multiplexing system - Google Patents
Optical path self-adaptive dispersion compensation method, optical module and wavelength division multiplexing system Download PDFInfo
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Abstract
The disclosure relates to an optical path adaptive dispersion compensation method, an optical module and a wavelength division multiplexing system. The optical path adaptive dispersion compensation method comprises the following steps: in a non-coherent wavelength division multiplexing system, a fiber Bragg grating is introduced into an optical module to perform optical path dispersion compensation. The optical module receiving end is integrated with the fiber Bragg grating to realize dispersion compensation of a transmission optical path system for the first time, an optical signal cannot be attenuated after passing through the grating, and extra power budget does not need to be considered when an optical interface index of the optical module is formulated.
Description
Technical Field
The present disclosure relates to the field of optical communications, and in particular, to an optical path adaptive dispersion compensation method, an optical module, and a wavelength division multiplexing system.
Background
In optical fiber communication systems, the dispersion problem is one of the main factors limiting the transmission distance, which can lead to signal pulse broadening, inter-symbol interference and increased error rate. The related technology WDM (coherent Wavelength Division Multiplexing) technology is not the second choice of the long-distance Wavelength Division system at present, and a system with a single wave of 100G or more can perform Chromatic Dispersion (CD) and PMD (Polarization Mode Dispersion) compensation through a DSP (Digital Signal Process) inside an optical module, thereby improving the transmission capability of the system.
WDM technology has a tendency like metro edge nodes sinking due to the proliferation of 5G and data center traffic. Optical modules in coherent WDM systems are costly, making incoherent WDM an alternative. While the incoherent scheme uses a direct modulation direct detection (IM-DD) optical module, and cannot perform electric domain dispersion compensation. Even when operating in the low dispersion O-band, the accumulated dispersion will incur a relatively high dispersion penalty after long-range transmission (e.g., 80km), limiting the system's level of further transmission.
Disclosure of Invention
The inventor discovers through research that: the related art commonly uses DCF (Dispersion Compensating Fiber) to compensate optical path Dispersion, which is also the most common Dispersion compensation scheme. But because of the extra loss associated with using a length of fiber, it is necessary to increase the power budget or add optical amplifiers to the system to compensate for attenuation.
In view of at least one of the above technical problems, the present disclosure provides an optical path adaptive dispersion compensation method, an optical module, and a wavelength division multiplexing system, which implement optical path dispersion compensation by using and integrating a Fiber Bragg Grating (FBG) inside the optical module.
According to an aspect of the present disclosure, there is provided an optical path adaptive dispersion compensation method, including:
in a non-coherent wavelength division multiplexing system, a fiber Bragg grating is introduced into an optical module to perform optical path dispersion compensation.
In some embodiments of the present disclosure, the performing optical path dispersion compensation includes:
through grating reflection and reflection time delay of optical signals with different wavelengths, chromatic dispersion generated after the optical signals are transmitted through the transmission optical fiber is compensated.
In some embodiments of the present disclosure, the introducing a fiber bragg grating in an optical module for optical path dispersion compensation includes:
obtaining the chromatic dispersion of an optical signal after the optical signal is transmitted by a transmission optical fiber;
determining a dispersion compensation value according to the chromatic dispersion;
the adjustment of the dispersion compensation value is achieved by changing the grating period or the refractive index.
In some embodiments of the present disclosure, the obtaining chromatic dispersion of the optical signal after being transmitted through the transmission fiber comprises:
acquiring the optical fiber length of a transmission optical fiber through which an optical signal passes;
and determining the accumulated dispersion value of the optical signal after transmission through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
In some embodiments of the present disclosure, the optical fiber length of the transmission optical fiber through which the optical signal is acquired includes:
and the optical fiber length of the transmission optical fiber is measured by the optical time domain reflectometer module arranged in the optical module.
In some embodiments of the present disclosure, the optical fiber length of the transmission optical fiber through which the optical signal is acquired includes:
receiving an optical signal sent by an opposite-end optical module, carrying out top-modulated signal analysis through a top-modulated signal demodulation device, and obtaining the sending optical power and the central wavelength of the opposite-end optical module, wherein the opposite-end optical module converts digital diagnosis monitoring information of the sending optical power and the central wavelength into a top-modulated signal which is superposed in a main service signal;
determining an optical signal attenuation value according to the transmitting optical power and the central wavelength of the opposite-end optical module and the digital diagnosis monitoring information of the receiving optical power of the local-end optical module;
and determining the optical fiber length of the transmission optical fiber through which the optical signal passes according to the attenuation coefficient and the optical signal attenuation value.
In some embodiments of the present disclosure, the adjusting the dispersion compensation value by changing the grating period or the refractive index comprises:
and the dispersion compensation value is adjusted by changing the stress or temperature parameter of the grating.
In some embodiments of the present disclosure, the introducing a fiber bragg grating in an optical module for optical path dispersion compensation further includes:
and under the condition that the application scene of the optical module is changed, recalculating the accumulated dispersion, and adjusting the stress or temperature parameter of the grating in real time to realize the adjustment of the dispersion compensation value.
According to another aspect of the present disclosure, there is provided a light module including:
and the FBG dispersion compensation unit is arranged in the optical module and is used for performing optical path dispersion compensation in the incoherent wavelength division multiplexing system.
In some embodiments of the present disclosure, the FBG dispersion compensation unit is configured to compensate chromatic dispersion generated after the optical signal is transmitted through the transmission fiber through grating reflection and reflection time delay of optical signals with different wavelengths.
In some embodiments of the present disclosure, the light module further comprises:
the chromatic dispersion measuring and calculating unit is used for obtaining the chromatic dispersion of the optical signal after the optical signal is transmitted by the transmission optical fiber;
the FBG dispersion compensation unit is used for determining a dispersion compensation value according to the chromatic dispersion; the adjustment of the dispersion compensation value is achieved by changing the grating period or the refractive index.
In some embodiments of the present disclosure, a chromatic dispersion estimation unit for obtaining a fiber length of a transmission fiber through which an optical signal passes; and determining the accumulated dispersion value of the optical signal after transmission through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
In some embodiments of the present disclosure, the chromatic dispersion measurement unit is configured to measure the optical fiber length of the transmission optical fiber through an optical time domain reflectometer module built in the optical module.
In some embodiments of the present disclosure, the light module further comprises:
the system comprises a top-tone signal analysis unit, a top-tone signal analysis unit and a main service signal analysis unit, wherein the top-tone signal analysis unit is used for receiving an optical signal sent by an opposite-end optical module, performing top-tone signal analysis through a top-tone signal demodulation device and obtaining the sending optical power and the central wavelength of the opposite-end optical module, and the opposite-end optical module converts the digital diagnosis monitoring information of the sending optical power and the central wavelength into a top-tone signal which is superposed in the main service signal;
the chromatic dispersion measuring and calculating unit is used for determining an optical signal attenuation value according to the digital diagnosis monitoring information of the transmitting optical power and the central wavelength of the opposite-end optical module and the receiving optical power of the local-end optical module; and determining the optical fiber length of the transmission optical fiber through which the optical signal passes according to the attenuation coefficient and the optical signal attenuation value.
In some embodiments of the present disclosure, the FBG dispersion compensation unit is configured to adjust the dispersion compensation value by changing a stress or temperature parameter of the grating.
In some embodiments of the present disclosure, the chromatic dispersion measurement and calculation unit is configured to recalculate the accumulated dispersion when the application scene of the optical module changes;
the FBG dispersion compensation unit is used for adjusting a dispersion compensation value in real time according to the recalculated accumulated dispersion; and adjusting the stress or temperature parameter of the grating in real time to realize the adjustment of the dispersion compensation value.
According to another aspect of the present disclosure, there is provided a wavelength division multiplexing system including the optical module according to any one of the embodiments described above.
The method and the device have the advantages that the FBG is integrated at the receiving end of the optical module for the first time to realize dispersion compensation of a transmission optical path system, the optical signal cannot be attenuated after passing through the grating, and extra power budget is not required to be considered when an optical interface index of the optical module is formulated.
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In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic diagram of some embodiments of the optical path adaptive dispersion compensation method according to the disclosure.
Figure 2 is a schematic diagram of the principle of chirped grating dispersion compensation in some embodiments of the present disclosure.
Fig. 3 is a schematic diagram of other embodiments of the optical path adaptive dispersion compensation method according to the disclosure.
Fig. 4 is a schematic diagram of some embodiments of an optical module of the present disclosure.
Fig. 5 is a schematic diagram of some embodiments of the disclosed wdm system.
FIG. 6 is a schematic diagram of other embodiments of an optical module of the present disclosure.
Fig. 7 is a schematic diagram of chromatic dispersion obtained by OTDR in some embodiments of the present disclosure.
Fig. 8 is a schematic diagram of chromatic dispersion obtained by a method of optical module tuning in some embodiments of the present disclosure.
Fig. 9 is a schematic diagram of still other embodiments of optical modules of the present disclosure.
Detailed Description
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 of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. 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.
The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
Fig. 1 is a schematic diagram of some embodiments of the optical path adaptive dispersion compensation method according to the disclosure. Preferably, the present embodiment can be performed by the optical module of the present disclosure. As shown in fig. 1, the optical path adaptive dispersion compensation method may include a step 10, in which:
and step 10, introducing fiber Bragg gratings into an optical module to perform optical path dispersion compensation in the incoherent wavelength division multiplexing system.
In some embodiments of the present disclosure, the Fiber Bragg Grating may be a CFBG (Chirped Fiber Bragg Grating).
In some embodiments of the present disclosure, the fiber bragg grating may be a chirped grating with a non-uniform period distribution.
In some embodiments of the present disclosure, the step of performing optical path dispersion compensation may include: through grating reflection and reflection time delay of optical signals with different wavelengths, chromatic dispersion generated after the optical signals are transmitted through the transmission optical fiber is compensated.
In some embodiments of the present disclosure, the transmission fiber may be a common single mode fiber.
In some embodiments of the present disclosure, in a WDM system, optical modules with different wavelengths need to consider grating bandwidth and period when selecting a grating, ensuring that the bragg condition is met to generate strong reflection at a specific wavelength.
According to the embodiment of the disclosure, through grating reflection and reflection time delay of optical signals with different wavelengths, the dispersion problem caused by transmission of signal light through a common single-mode optical fiber is compensated, and an original signal is recovered.
The dispersion compensation scheme implemented by the embodiment of the disclosure based on the optical module respectively compensates each channel of the WDM system without considering dispersion conditions of other channels in the system, and is more suitable for the characteristic of flexible networking of the current optical transmission network.
The fiber bragg grating disclosed by the embodiment of the disclosure has the advantages of small volume, low insertion loss, good compatibility with optical fibers, small nonlinear influence and easiness in integration with an optical module.
Figure 2 is a schematic diagram of the principle of chirped grating dispersion compensation in some embodiments of the present disclosure. As shown in fig. 2, for an optical signal with an arbitrary wavelength, the transmission speed of the short wavelength (blue shift) component is fast, and the transmission speed of the long wavelength (red shift) component is slow, so that the optical signal is broadened after being transmitted through the optical fiber. Therefore, the grating with the period varying along the axial direction is selected, and when the bragg condition is met, optical signals with different wavelength components enter the grating and are reflected at different positions. If the end with the large grating period is placed in front, the red shift component is reflected when the red shift component reaches the Bragg condition; the end with small grating period is placed at the back, so that the blue shift component is reflected at the back end of the grating, and the expanded signal can be restored.
Fig. 3 is a schematic diagram of other embodiments of the optical path adaptive dispersion compensation method according to the disclosure. Preferably, the present embodiment can be performed by the optical module of the present disclosure. As shown in fig. 3, the optical path adaptive dispersion compensation method may include at least one of steps 11 to 14, wherein:
and step 11, in the incoherent wavelength division multiplexing system, obtaining the chromatic dispersion of the optical signal after being transmitted by the transmission optical fiber.
In some embodiments of the present disclosure, step 11 may include at least one of steps 111-112, wherein:
step 111, obtaining the optical fiber length of the transmission optical fiber through which the optical signal passes.
In some embodiments of the present disclosure, step 111 may comprise: and the optical fiber length of the transmission optical fiber is measured by the optical time domain reflectometer module arranged in the optical module.
In other embodiments of the present disclosure, step 111 may include at least one of steps 1111-1113, wherein:
and 1111, receiving an optical signal sent by the opposite-end optical module, performing a tuning signal analysis through the tuning signal demodulation device, and obtaining a sending optical power and a center wavelength of the opposite-end optical module, wherein the opposite-end optical module converts digital diagnosis monitoring information of the sending optical power and the center wavelength into a tuning signal and superimposes the tuning signal on the main service signal.
Step 1112, determining an optical signal attenuation value according to the transmitting optical power and the center wavelength of the peer optical module and the digital diagnostic monitoring information of the receiving optical power of the home optical module.
And 1113, determining the optical fiber length of the transmission optical fiber through which the optical signal passes according to the attenuation coefficient and the optical signal attenuation value.
And step 112, determining an accumulated dispersion value of the optical signal after being transmitted through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
And step 12, determining a dispersion compensation value according to the chromatic dispersion.
In some embodiments of the present disclosure, the FBG dispersion compensation value DFBGIt may be preconfigured according to equation (1):
Ds(λ)*L＝-α*DFBG(λ) (1)
d in formula (1)s(lambda) is the dispersion coefficient of wavelength lambda in common single mode fiber, L is the fiber length, and the grating length is negligible relative to the fiber length. Considering zero dispersion easily makes the optical signal satisfy the phase matching condition, thereby generating the nonlinear effect. If the transmission performance is degraded due to the non-linearity problem, the dispersion compensation value DFBG can be adjusted to perform over-compensation or under-compensation, and the conversion factor alpha is not equal to 1.
In some embodiments of the present disclosure, the setting of the dispersion compensation value needs to be considered in combination with multiple parameters such as transmission distance of the optical module, operating wavelength, and the like, so as to evaluate the accumulated dispersion value generated after transmission through the common single-mode optical fiber. The embodiments of the present disclosure provide a method for dynamically adjusting a chromatic dispersion compensation value, in which a reflection wavelength is related to a grating period and an effective refractive index of a grating region, the reflection wavelength is adjusted by applying stress or changing temperature to a grating, and a relationship between chromatic dispersion compensation and actually generated chromatic dispersion is established.
In some embodiments of the present disclosure, the chromatic dispersion of a common single-mode optical fiber is calculated by real-time measurement or out-of-band modulation (e.g., tuning) of an optical module.
And step 13, adjusting the dispersion compensation value by changing the grating period or the refractive index.
In some embodiments of the present disclosure, step 13 may comprise: and the dispersion compensation value is adjusted by changing the stress or temperature parameter of the grating.
And 14, under the condition that the application scene of the optical module is changed, recalculating the accumulated dispersion, and adjusting the stress or temperature parameter of the grating in real time to realize the adjustment of the dispersion compensation value.
The above embodiment of the present disclosure provides for integrating FBGs at the receiving end of the optical module to implement dispersion compensation of the transmission optical path system for the first time. The FBG of the embodiment of the disclosure has the advantages of small volume, low insertion loss, good compatibility with optical fibers, small nonlinear influence, easy integration with optical modules and high cost performance.
Different from the DCF scheme, the optical signal in the embodiment of the disclosure hardly generates attenuation after passing through the grating, and an additional power budget does not need to be considered when an optical interface index of the optical module is formulated. The dispersion compensation scheme implemented by the above embodiments of the present disclosure based on the optical module respectively compensates for each wavelength, which can avoid changing the configuration of the entire wavelength division system and reduce the influence on other channels in the wavelength division system.
Fig. 4 is a schematic diagram of some embodiments of an optical module of the present disclosure. As shown in fig. 4, the optical module of the present disclosure may include an FBG dispersion compensation unit 41 disposed inside the optical module, wherein:
and an FBG dispersion compensation unit 41 for performing optical path dispersion compensation in the incoherent wavelength division multiplexing system.
In some embodiments of the present disclosure, the FBG dispersion compensation unit is configured to compensate chromatic dispersion generated after the optical signal is transmitted through the transmission fiber through grating reflection and reflection time delay of optical signals with different wavelengths.
In some embodiments of the present disclosure, as shown in fig. 4, service signal light with a certain wavelength is transmitted through an optical fiber with a certain length to generate chromatic dispersion, and enters an FBG chromatic dispersion compensation unit inside an optical module, wavelength components meeting a bragg condition are strongly reflected in sequence, and a small amount of remaining light is not processed as transmitted light. The FBG dispersion compensation unit is a fiber grating with a period changing, so that the expanded service signal is adjusted and recovered. The recovered service signal sequentially passes through core photoelectric devices such as a light signal receiving detection unit (PIN/APD), a TIA (Trans-Impedance Amplifier), a LA (Linear Amplifier) and the like, and is finally converted into a complete electric signal to be output, wherein the PIN is a photodiode, and the APD is an Avalanche Photon Diode.
Fig. 5 is a schematic diagram of some embodiments of the disclosed wdm system. As shown in fig. 5, the wavelength division multiplexing system of the present disclosure may include a first optical module 51 and a second optical module 52, wherein the first optical module 51 and the second optical module 52 are connected by an optical fiber, and the first optical module 51 and the second optical module 52 are opposite optical modules.
In some embodiments of the present disclosure, the disclosed wavelength division multiplexing system may be a non-coherent wavelength division multiplexing system.
The wavelength division multiplexing system can realize optical path self-adaptive dispersion compensation based on the optical module.
In some embodiments of the present disclosure, the first and second light modules 51 and 52 may be single channel IM-DD light modules.
In some embodiments of the present disclosure, the first and second optical modules 51 and 52 each include a transmitting side structure and a receiving side structure.
In some embodiments of the present disclosure, the first optical module 51 and the second optical module 52 may be implemented as the optical module described in any of the above embodiments (for example, the embodiment of fig. 4).
In some embodiments of the present disclosure, the single channel optical module (e.g., first optical module 51) using IM-DD technology has only one laser on the transmit side, which is modulated to produce an output optical signal with a unique center wavelength. The output optical signal is transmitted in the optical fiber, and due to different propagation speeds of different frequency components, the optical signal pulse is broadened, and chromatic dispersion is formed, so that the transmission performance is affected.
In some embodiments of the present disclosure, the laser of the first optical module 51 is modulated to generate an output optical signal with a unique center wavelength. The output optical signal is transmitted in an 80km optical fiber, and due to different propagation speeds of different frequency components, the optical signal pulse is broadened, and chromatic dispersion is generated. The receiving end of the second optical module 52 integrates a chromatic dispersion measuring and calculating unit, and performs dispersion calculation on the optical signal transmitted by the common single-mode optical fiber. The length of the optical fiber is obtained first, and then the accumulated dispersion value of the optical signal under the wavelength is calculated by combining the dispersion coefficient and the dispersion slope.
FIG. 6 is a schematic diagram of other embodiments of an optical module of the present disclosure. The optical module as shown in fig. 5 (e.g. the second optical module 52 of the embodiment of fig. 5) may include a chromatic dispersion evaluating unit 42 and an FBG dispersion compensating unit 41, wherein:
in some embodiments of the present disclosure, the optical module as shown in fig. 6 may be a single channel optical module using IM-DD technology.
The chromatic dispersion measuring and calculating unit 42 is configured to obtain the chromatic dispersion of the optical signal after being transmitted through the transmission fiber.
In some embodiments of the present disclosure, the chromatic dispersion estimation unit 42 may be configured to obtain a fiber length of a transmission fiber through which the optical signal passes; and determining the accumulated dispersion value of the optical signal after transmission through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
In some embodiments of the present disclosure, the chromatic dispersion measuring unit 42 may be configured to perform dispersion calculation on the optical signal transmitted through the common single-mode fiber, that is, obtain the length of the optical fiber first, and then calculate the cumulative dispersion value of the optical signal at the wavelength by combining the dispersion coefficient and the dispersion slope.
An FBG dispersion compensation unit 41 for determining a dispersion compensation value according to the chromatic dispersion; the adjustment of the dispersion compensation value is achieved by changing the grating period or the refractive index.
In some embodiments of the present disclosure, the FBG dispersion compensation unit 41 may be configured to compensate for dispersion generated in the system by a chirped FBG integrated inside an optical module (e.g., the second optical module 52 of the embodiment of fig. 5); selecting a proper dispersion compensation value according to the calculated accumulated dispersion; and then the desired dispersion compensation value is adjusted by changing the stress or temperature parameter of the grating.
In some embodiments of the present disclosure, when the application scene of the optical module changes, for example, the transmission distance changes, the chromatic dispersion measuring and calculating unit 42 at the receiving end of the optical module recalculates the accumulated dispersion, and the FBG dispersion compensating unit 41 adjusts the relevant parameters in real time, so as to meet the requirement of the system dispersion compensation.
In some embodiments of the present disclosure, the chromatic dispersion estimation unit 42 may be configured to calculate the chromatic dispersion of the common single-mode fiber by real-time measurement or by out-of-band modulation (e.g., tuning) of the optical module.
The following describes two ways of obtaining the chromatic dispersion of a common single-mode fiber by using the chromatic dispersion measuring and calculating unit through specific embodiments.
Mode one, real-time measurement
In some embodiments of the present disclosure, the chromatic dispersion measurement unit 42 may be configured to measure the length of the transmission fiber through an OTDR (Optical Time-Domain Reflectometer) module built in the Optical module.
Fig. 7 is a schematic diagram of chromatic dispersion obtained by OTDR in some embodiments of the present disclosure. Fig. 7 also shows a schematic structural diagram of the transmitting side of the optical module of the present disclosure.
As shown in fig. 7, the OTDR module built in the optical module measures the length of the optical fiber, and further calculates the dispersion after transmission through the optical fiber. As shown in fig. 7, an OTDR functional module is integrated on the transmission side of the optical module, and is coupled to the main service optical signal through a multiplexer/demultiplexer. The method can detect the length of the optical fiber transmitted by the optical module, calculate the accumulated dispersion transmitted by the optical fiber according to the central wavelength of the optical module, and report the result through an Inter-Integrated Circuit (IIC) interface.
Mode two, optical module out-of-band top-adjusting mode calculation
Fig. 8 is a schematic diagram of chromatic dispersion obtained by a method of optical module tuning in some embodiments of the present disclosure. Fig. 8 is a schematic diagram of additional embodiments of the disclosed wdm system. The embodiment of fig. 8 uses optical module peaking techniques for dispersion estimation. In the embodiment of fig. 8, a low-frequency small-amplitude signal is superimposed on a high-speed service signal, so as to transmit some OAM (Operation Administration Maintenance) information of the optical module. As shown in fig. 8, the transmission optical power DDM (Digital Diagnostic Monitoring) information and the center wavelength of the optical module 2 are converted into a set-top signal and superimposed on the main traffic signal. The optical module 1 receives the optical information or analyzes the modulated signal through the modulated signal demodulation device, thereby obtaining the transmitting optical power and the central wavelength of the optical module 2. The optical module MCU (Microcontroller Unit, microcontrol Unit) obtains the optical signal attenuation according to the information and the received optical power DDM of the optical module 1. Under the condition of known attenuation coefficient, the length of the optical fiber can be calculated, and then the accumulated dispersion after the optical fiber is transmitted through the section of the optical fiber is calculated according to the method of the mode one. Compared with the first mode, the second mode does not need to introduce an additional light source and a detection device, and the cost is low.
Fig. 9 is a schematic diagram of still other embodiments of optical modules of the present disclosure. The optical module shown in fig. 9 (for example, the second optical module 52 in the embodiment of fig. 5 or the optical module 1 in the embodiment of fig. 8) may include a tuning signal analyzing unit 43, a chromatic dispersion measuring unit 42, and an FBG dispersion compensating unit 41, where:
a top-tone signal analyzing unit 43, configured to receive an optical signal sent by an opposite-end optical module, perform top-tone signal analysis through a top-tone signal demodulating apparatus, and obtain a sending optical power and a center wavelength of the opposite-end optical module, where the opposite-end optical module converts digital diagnosis monitoring information of the sending optical power and the center wavelength into a top-tone signal, and superimposes the top-tone signal in the main service signal;
the chromatic dispersion measuring and calculating unit 42 is configured to determine an optical signal attenuation value according to digital diagnosis monitoring information of the transmission optical power and the center wavelength of the opposite-end optical module and the reception optical power of the local-end optical module; determining the optical fiber length of the transmission optical fiber through which the optical signal passes according to the attenuation coefficient and the optical signal attenuation value; and determining the accumulated dispersion value of the optical signal after transmission through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
An FBG dispersion compensation unit 41 for determining a dispersion compensation value according to the chromatic dispersion; the adjustment of the dispersion compensation value is achieved by changing the grating period or the refractive index.
In the incoherent WDM system, the chirped fiber bragg grating is introduced into the optical module to implement the dispersion compensation function.
The above embodiments of the present disclosure establish a relationship between a dispersion compensation value and actually generated chromatic dispersion, and adopt a mechanism for adaptively adjusting the dispersion compensation value. That is, the chromatic dispersion of the transmission fiber is obtained by calculation or measurement, the dispersion compensation value to be adjusted is found, and then the adjustment of the dispersion compensation value is realized by changing the grating period or the refractive index.
The above embodiments of the present disclosure use a Fiber Bragg Grating (FBG) and integrate the FBG inside an optical module to implement optical path dispersion compensation. According to the embodiment of the disclosure, through grating reflection and reflection time delay of optical signals with different wavelengths, the dispersion problem caused by transmission of signal light through a common single-mode optical fiber is compensated, and an original signal is recovered. The optical module of the embodiment of the disclosure can adjust the dispersion compensation value in real time by measuring and calculating the accumulated dispersion so as to meet the requirements of different transmission distance scenes.
The embodiment of the disclosure realizes low-cost adaptive dispersion compensation through the optical module without replacing the existing network equipment.
The grating dispersion compensation method provided by the embodiment of the disclosure is realized based on the existing optical devices (such as gratings and OTDRs) and technical schemes (such as top-tuning), and the industrial chain support is good. The chirped grating has the advantages of small volume, low insertion loss, good compatibility with optical fibers, small nonlinear influence, easy integration with an optical module and high cost performance. The embodiment of the disclosure is introduced into the optical module in an integrated manner, and only a certain cost of the optical module is increased, so that the existing network equipment can be used.
The above-described tuning signal parsing unit 43 and chromatic dispersion estimation unit 42 may be implemented as a general purpose processor, a Programmable Logic Controller (PLC), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof, for performing the functions described herein.
Thus far, the present disclosure has been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware to implement the above embodiments, where the program may be stored in a non-transitory computer readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic or optical disk, and the like.
The description of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.
Claims (17)
1. An optical path adaptive dispersion compensation method, comprising:
in a non-coherent wavelength division multiplexing system, a fiber Bragg grating is introduced into an optical module to perform optical path dispersion compensation.
2. The optical path adaptive dispersion compensation method according to claim 1, wherein the performing optical path dispersion compensation comprises:
through grating reflection and reflection time delay of optical signals with different wavelengths, chromatic dispersion generated after the optical signals are transmitted through the transmission optical fiber is compensated.
3. The optical path adaptive dispersion compensation method according to claim 1 or 2, wherein the introducing a fiber bragg grating in the optical module for optical path dispersion compensation comprises:
obtaining the chromatic dispersion of an optical signal after the optical signal is transmitted by a transmission optical fiber;
determining a dispersion compensation value according to the chromatic dispersion;
the adjustment of the dispersion compensation value is achieved by changing the grating period or the refractive index.
4. The method according to claim 3, wherein the obtaining chromatic dispersion of the optical signal after being transmitted through the transmission fiber comprises:
acquiring the optical fiber length of a transmission optical fiber through which an optical signal passes;
and determining the accumulated dispersion value of the optical signal after transmission through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
5. The optical path adaptive dispersion compensation method according to claim 4, wherein the optical fiber length of the transmission fiber through which the obtained optical signal passes includes:
and the optical fiber length of the transmission optical fiber is measured by the optical time domain reflectometer module arranged in the optical module.
6. The optical path adaptive dispersion compensation method according to claim 4, wherein the optical fiber length of the transmission fiber through which the obtained optical signal passes includes:
receiving an optical signal sent by an opposite-end optical module, carrying out top-modulated signal analysis through a top-modulated signal demodulation device, and obtaining the sending optical power and the central wavelength of the opposite-end optical module, wherein the opposite-end optical module converts digital diagnosis monitoring information of the sending optical power and the central wavelength into a top-modulated signal and superposes the top-modulated signal in a main service signal;
determining an optical signal attenuation value according to the transmitting optical power and the central wavelength of the opposite-end optical module and the digital diagnosis monitoring information of the receiving optical power of the local-end optical module;
and determining the optical fiber length of the transmission optical fiber through which the optical signal passes according to the attenuation coefficient and the optical signal attenuation value.
7. The optical path adaptive dispersion compensation method according to claim 3, wherein the adjusting the dispersion compensation value by changing the grating period or the refractive index comprises:
and the dispersion compensation value is adjusted by changing the stress or temperature parameter of the grating.
8. The method according to claim 3, wherein the introducing a fiber bragg grating into the optical module for optical path dispersion compensation further comprises:
and under the condition that the application scene of the optical module is changed, recalculating the accumulated dispersion, and adjusting the stress or temperature parameter of the grating in real time to realize the adjustment of the dispersion compensation value.
9. A light module, comprising:
and the FBG dispersion compensation unit is arranged in the optical module and is used for performing optical path dispersion compensation in the incoherent wavelength division multiplexing system.
10. The light module of claim 9,
and the FBG dispersion compensation unit is used for compensating the chromatic dispersion generated after the optical signals are transmitted by the transmission optical fiber through grating reflection and the reflection time delay of the optical signals with different wavelengths.
11. The light module according to claim 9 or 10, further comprising:
the chromatic dispersion measuring and calculating unit is used for acquiring the chromatic dispersion of the optical signal after the optical signal is transmitted by the transmission optical fiber;
the FBG dispersion compensation unit is used for determining a dispersion compensation value according to the chromatic dispersion; the adjustment of the dispersion compensation value is achieved by changing the grating period or the refractive index.
12. The light module of claim 11,
the chromatic dispersion measuring and calculating unit is used for acquiring the optical fiber length of a transmission optical fiber through which an optical signal passes; and determining the accumulated dispersion value of the optical signal after transmission through the section of transmission optical fiber according to the optical fiber length, the central wavelength of the optical module, the dispersion coefficient and the dispersion slope.
13. The light module of claim 12,
and the chromatic dispersion measuring and calculating unit is used for measuring the optical fiber length of the transmission optical fiber through an optical time domain reflectometer module arranged in the optical module.
14. The light module of claim 12, further comprising:
the system comprises a top-tone signal analysis unit, a top-tone signal analysis unit and a main service signal analysis unit, wherein the top-tone signal analysis unit is used for receiving an optical signal sent by an opposite-end optical module, performing top-tone signal analysis through a top-tone signal demodulation device and obtaining the sending optical power and the central wavelength of the opposite-end optical module, and the opposite-end optical module converts the digital diagnosis monitoring information of the sending optical power and the central wavelength into a top-tone signal which is superposed in the main service signal;
the chromatic dispersion measuring and calculating unit is used for determining an optical signal attenuation value according to the digital diagnosis monitoring information of the transmitting optical power and the central wavelength of the opposite-end optical module and the receiving optical power of the local-end optical module; and determining the optical fiber length of the transmission optical fiber through which the optical signal passes according to the attenuation coefficient and the optical signal attenuation value.
15. The light module of claim 11,
and the FBG dispersion compensation unit is used for realizing the adjustment of the dispersion compensation value by changing the grating stress or temperature parameter.
16. The light module of claim 11,
the chromatic dispersion measuring and calculating unit is used for recalculating the accumulated dispersion under the condition that the application scene of the optical module is changed;
the FBG dispersion compensation unit is used for adjusting a dispersion compensation value in real time according to the recalculated accumulated dispersion; and adjusting the stress or temperature parameter of the grating in real time to realize the adjustment of the dispersion compensation value.
17. A wavelength division multiplexing system comprising an optical module according to any of claims 9-16.
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