CN-122027015-A - Optical module integrating OTDR and delay self-adaptive compensation function and working method thereof

CN122027015ACN 122027015 ACN122027015 ACN 122027015ACN-122027015-A

Abstract

The invention discloses an optical module integrating OTDR and delay self-adaptive compensation functions and a working method thereof, which realize closed loop integration of link diagnosis and performance optimization, wherein the link state sensing capability of optical time domain reflection and the measurement and compensation capability of transmission delay are deeply combined into a single optical module, so that the module can not only locate optical fiber faults, but also directly optimize own transmission performance by utilizing diagnosis information to form an intelligent closed loop of perception-decision-execution. The system realizes nanosecond real-time delay compensation at the source of a physical layer, and performs rapid and self-adaptive digital domain delay adjustment on a service data stream by integrating a signal processing and FPGA unit in an optical module directly based on the physical length of an optical fiber measured by OTDR or the delay change monitored in real time. The compensation point is sunk to the link closest to the physical link, so that the real-time performance and the precision of compensation are remarkably improved, and the harsh requirements of scenes such as high-precision time synchronization and the like are met.

Inventors

YANG MENGJUAN
Du Xuebo
XIAO TAO
LI JING
WANG KE
Ma Hangyi
WANG YUANPING
PENG BO
REN WENPING
ZHOU ZHENGDUAN

Assignees

上海宽域工业网络设备有限公司

Dates

Publication Date: 20260512
Application Date: 20260320

Claims (8)

1. The optical module integrating the OTDR and the delay self-adaptive compensation function is characterized by comprising an optical transmitting assembly, a miniature OTDR detection unit, an optical receiving assembly and an integrated signal processing and FPGA unit; the light emitting assembly comprises a laser driver and a first laser, and is used for emitting high-speed service light signals in a normal service mode; The miniature OTDR detection unit is in optical path coupling with the optical emission component through an internal optical splitter, and comprises a pulse generation circuit and a driving and light source module, wherein the driving and light source module comprises a second laser which can emit light with different wavelengths from that of service light, and the second laser is driven by the pulse generation circuit to emit low-power test light pulses; The service optical signal and the test optical pulse are both injected into an optical fiber link connected with an optical module through an optical splitter; the optical receiving assembly comprises a photoelectric detector and a transimpedance amplifier, and is used for receiving a business optical signal from an optical fiber link and converting the business optical signal into an electric signal; the integrated signal processing and FPGA unit comprises three functional sub-modules, wherein the three functional sub-modules are respectively a reflected signal analysis module, a delay measurement module and a self-adaptive compensation module; The input end of the reflected signal analysis module is connected with a high-speed analog-to-digital converter ADC, the high-speed analog-to-digital converter ADC is used for specially sampling a back scattered light signal which is generated by Rayleigh scattering and Fresnel reflection in an optical fiber and returns along an original path, the returned back scattered light signal is guided to an OTDR (optical time domain reflectometer) receiving photoelectric detector through the same optical divider to carry out photoelectric conversion, the specific working principle of the reflected signal analysis module is that an FPGA (field programmable gate array) records the accurate transmitting time t0 of a test light pulse, digital average and logarithmic conversion processing is carried out on the reflected signal obtained by sampling the ADC to form an event curve, and the reflected peak on the event curve is detected and the arrival time t1 is recorded according to the formula Wherein c is the speed of light in vacuum, n is the refractive index of the optical fiber, the position of a fault point is accurately calculated, and the total physical length L of the optical fiber link is obtained at the same time; The delay measurement module directly receives the total length L of the optical fiber link output by the reflected signal analysis module, and fixes the delay according to a formula Calculating the theoretical transmission delay of the optical fiber link; the self-adaptive compensation module receives delay data from the delay measurement module, the core of the self-adaptive compensation module is a digital delay line which is realized by FPGA logic and has dynamically configurable depth, for a sending path, the FPGA firstly writes the service data into a first-in first-out buffer area before sending the service data to a laser driver, and a delay control state machine precisely controls a reading clock or an enabling signal of the buffer area according to compensation requirements so as to realize pre-delay of a transmitting signal, and for a receiving path, the FPGA processes the service data sampled from a post-stage ADC of a transimpedance amplifier by a similar digital delay line so as to realize receiving calibration.
2. The optical module integrating OTDR and delay self-adaptive compensation function of claim 1, wherein the delay measurement module is further capable of measuring an end-to-end actual total transmission delay T_total by analyzing timestamp information carried in a service signal and comparing the timestamp information with a local clock.
3. The optical module integrating OTDR and delay self-adaptive compensation function according to claim 1, wherein the compensation accuracy in the self-adaptive compensation module is guaranteed by a system clock period of up to hundreds of picoseconds of an FPGA and a fine-tuning digital delay unit based on a phase interpolator.
4. The optical module integrating OTDR and delay adaptive compensation function of claim 1, wherein the first laser is a direct modulation laser or an electroabsorption modulation laser.
5. The optical module integrating OTDR and delay adaptive compensation function of claim 1, wherein the second laser is an edge-emitting laser or a vertical cavity surface emitting laser.
6. The optical module integrating OTDR and delay self-adaptive compensation function of claim 1 further comprising a management interface, wherein the management interface is a standard I2C or MDIO interface and is used for communicating with a host device, reporting an OTDR diagnosis result, a current delay value and a compensation state, and receiving a configuration instruction.
7. A method for operating an optical module integrating OTDR and delay adaptive compensation functions according to any one of claims 1-6, characterized by the specific steps of: step S1, periodic link diagnosis and measurement; The FPGA controls the miniature OTDR detection unit to emit a series of test light pulses, and simultaneously starts the reflected signal analysis module to perform high-speed sampling and data processing; s2, calculating the length of the optical fiber and fault location; The reflected signal analysis module completes event curve analysis, accurately calculates the total physical length L of the optical fiber link, and identifies and locates break points, positions and losses of connector events, and generates structural diagnosis data; s3, calculating transmission delay; The delay measurement module calculates theoretical optical fiber delay T_fiber based on the length L obtained in the step S2 and a preset optical fiber refractive index n; step S4, real-time self-adaptive compensation; The self-adaptive compensation module converts the delay value obtained in the step S3 into a specific digital delay line control parameter, and the FPGA dynamically adjusts the depth of the digital delay line in the sending and/or receiving direction on a service data flow path immediately to finish real-time compensation of transmission delay; step S5, data reporting and state synchronization; The optical module reports the diagnosis result of the step S2 and the delay measured value of the step S3 to the host network management system through the management interface, and the whole measurement-compensation process can run periodically under the condition that the service is not interrupted, thereby realizing closed-loop self-adaptive control.
8. The method of claim 7, wherein in step S3 of calculating the transmission delay, the delay measuring module monitors the service channel at the same time and calculates the actual dynamic delay through the timestamp protocol.

Description

Optical module integrating OTDR and delay self-adaptive compensation function and working method thereof Technical Field The invention relates to the technical field of optical fiber communication, in particular to an optical module with optical fiber link diagnosis, fault location and transmission delay dynamic compensation capability and a working method thereof. Background Optical fiber communication is used as a foundation of modern information society, and the physical state and transmission performance of a link directly determine the stability and reliability of a communication system. Optical Time Domain Reflectometry (OTDR) technology is a core means of diagnosing fiber link failures (e.g., breaks, bends) and monitoring losses. Traditionally, OTDR is used as an independent handheld instrument, and cannot realize online and real-time link monitoring, so that operation and maintenance efficiency is low. For this reason, the industry proposes solutions for integrating OTDR functions inside an optical module to achieve online intelligent operation and maintenance of an optical fiber link. For example, huacheng technology limited discloses an optical module, a control unit of which can be switched between an OTDR mode and a service mode, and an OTDR signal returned by an optical fiber is received and analyzed by a first optical receiving unit for optical signal transmission analysis. The optical science and technology corporation discloses a DWDM ROF module with OTDR function, which integrates an FPGA (field programmable gate array) for generating OTDR pulse electric signals and analyzing and processing reflected signals. In addition, qingdao Xinghuang photoelectric technology Inc., solar light Ai Rui photoelectric technology Inc. also discloses various optical module designs integrating OTDR functions. The problems of miniaturized integration and on-line monitoring of the OTDR function are effectively solved in the prior art, but the function positioning is still limited to link fault diagnosis and state monitoring. On the other hand, in application scenarios where high precision time synchronization, 5G forwarding, industrial control, etc. are extremely sensitive to transmission delay, the fixed transmission delay introduced by the optical fiber link and its environmental fluctuations become key factors affecting the system performance. There are various schemes for measuring and compensating the transmission delay of optical fibers in the prior art. For example, the Zhongxing communication stock limited company discloses an automatic compensation method for the asymmetric time delay of optical fibers for medium-length transmission, and the Fujian Beijing-ao communication technology limited company discloses a time delay compensation method for an optical fiber transmission system, and signal synchronization is realized by calculating and compensating the total time delay values of different optical remote unit paths. In the field of higher precision fiber time transfer, the prior art generally combines FPGAs with phase-locked loop (PLL) phase shifters to achieve large-scale, high-resolution delay control. However, these delay compensation techniques exist mostly as independent system level schemes or devices, where the measurement means (e.g. based on a time stamp protocol) and the compensation execution units (e.g. upper switching devices or dedicated synchronization devices) are separate from the optical modules as physical layer transceivers. In summary, the prior art mainly has the following problems and disadvantages: (1) The function is split and a closed loop cannot be formed, namely the existing optical module integrated with the OTDR function is only used for outputting diagnosis information such as link loss, event point position and the like, and the optical module belongs to sensing only and not executing. The method can not further convert the key information of the physical length of the optical fiber link accurately measured by the OTDR into the optical fiber transmission delay parameter and is used for driving real-time performance compensation. (2) The delay compensation scheme is independent of the optical module, the closed loop path for measurement, calculation and compensation is long, signals are required to be processed through multi-stage equipment, real-time and self-adaptive compensation in nanosecond or picosecond level cannot be realized, and the harsh requirements of ultra-low delay application scenes are difficult to meet. (3) The system is complex, the integration level is low, and the link diagnosis (OTDR) and the performance optimization (delay compensation) are respectively realized by different devices, so that the complexity, the cost and the power consumption of the system are increased, and the miniaturization and the deployment convenience of the devices are not facilitated. Therefore, a highly integrated solution is needed in the art, which can deeply integrate