Optical Transceiver Idle Signal Modulation for Unused Path Detection
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Solution Overview
Problem
Existing optical fiber identification techniques are limited in long-distance communication due to the need for two separate transmitters and the inability to use relay amplifiers, resulting in high costs and short-distance limitations, and struggle to accurately detect unused paths in redundant optical transmission systems.
Innovation Solution
An optical transmission system that uses a control modulation unit to modulate an optical signal with an idle signal at a fixed period, allowing detection of unused paths through a pulsed OAM signal, utilizing a single wavelength and enabling the use of relay amplifiers for long-distance communication without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If identification light with different wavelength is transmitted to detect unused path, then unused path detection is enabled, but relay amplifiers cannot be used and communication distance is limited
Solution Approach 1:
The optical transmitter is designed to perform multiple functions: it transmits both actual data signals and identification light for unused path detection using the same device. The identification light is transmitted only when the optical signal is idle, allowing the same hardware to serve both communication and detection purposes without requiring separate dedicated transmitters for each function.
Solution Approach 2:
The identification light is transmitted periodically at fixed intervals when the optical signal is idle, rather than continuously. This periodic transmission allows the system to detect unused paths while minimizing interference with actual data transmission and enabling relay amplifiers to function properly during active communication periods.
2Measurement precision
If two separate transmitters are used for optical signal and identification light, then unused path detection is enabled, but device complexity and cost increase
Solution Approach 1:
The optical transmitter is designed to perform multiple functions: it transmits both actual data signals and identification light for unused path detection using the same device. The identification light is transmitted only when the optical signal is idle, allowing the same hardware to serve both communication and detection purposes without requiring separate dedicated transmitters for each function.
Solution Approach 2:
The functions of transmitting actual data and detecting unused paths are merged into a single optical transmitter device. By combining these functions, the system reduces hardware complexity and cost while maintaining the capability to accurately detect unused paths through intelligent control of when identification light is transmitted.
3Reliability
If OAM signal transmission continues on unused path, then path monitoring is maintained, but operator error in connector handling increases risk
Solution Approach 1:
The system performs preliminary detection of unused paths by transmitting identification light before any physical connector operations are performed. This allows the system to identify which paths are actually unused and potentially mark or alert operators about these paths, reducing the risk of accidentally disconnecting active connections during maintenance operations.
Solution Approach 2:
The system provides feedback about the status of each optical path (used or unused) based on detection results. This feedback mechanism helps operators make informed decisions during connector handling, reducing the risk of errors by clearly indicating which paths are safe to disconnect and which are actively in use.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable detection of unused paths in long-distance redundant networks at a lower cost by using a single wavelength and existing optical transceivers with FPGA-based control modulation, reducing the need for additional devices and maintaining signal integrity.
Implementation Method 1
a control signal for modulating, at a fixed modulation period, an optical signal on which an idle signal with empty data is superimposed
Implementation Method 2
the identification light is detected by detecting leakage light generated due to the bending, using the optical fiber identifier
Data Source
AI summary
A function of detecting an unused path through which actual data is not transmitted in a long-distance redundant network is realized at low cost. In an optical transmission system 20, each of the optical transceivers 21a and 21b that are connected to each other by an optical fiber cable 22 and disposed separately includes a protocol IC unit 35. The protocol IC unit 35 transmits an idle signal A1 with empty data using an optical signal P1 to an unused path of the optical fiber cable 22. At the time of this transmission, the protocol IC unit 35 outputs, to the transmission unit 33, a control signal C1 for performing, at a fixed modulation period, ON/OFF modulation on the optical signal P1 on which the idle signal A1 is superimposed. Also, the protocol IC unit 35 transmits an OAM signal O1 at an OAM period that is a period different from a modulation period, and performs control to turn ON the control signal C1 at the time of this transmission. The protocol IC unit 35 performs control to set the QAM period T2 as a period longer than or equal to a plurality of modulation periods T1. The transmission unit 33 is configured to perform ON/OFF modulation on the optical signal P1 using the control signal C1, and transmits the modulated optical signal P1.