Vibration Detection via Optical Phase Recovery in Coherent Transponders
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Solution Overview
Problem
Existing optical communication systems lack an efficient method for vibration detection that does not disrupt data transmission and requires dedicated channels, leading to high overhead costs and noise interference.
Innovation Solution
Implementing a digital coherent transponder with adaptive DSP operations to track optical phase, utilizing ultra-low linewidth lasers and phase-locked loops to extract vibration-induced phase changes from existing optical communication systems, allowing for vibration monitoring as an auxiliary function without dedicated sensing channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated vibration sensing channels are implemented, then vibration detection capability is improved, but system overhead cost and complexity increase
Solution Approach 1:
The patent enables existing optical communication transponders to perform dual functions: data transmission and vibration sensing. By utilizing the optical phase information already tracked during coherent detection for data communication, the system adds vibration sensing capability without requiring dedicated sensing transponders or separate channels, thereby reducing system overhead cost and complexity while maintaining vibration detection capability
Solution Approach 2:
The system uses its own existing resources (optical phase tracking capability in coherent receivers) to provide vibration sensing functionality. The phase information that is already being processed for data demodulation is repurposed for vibration detection, eliminating the need for external or dedicated sensing infrastructure
2Productivity
If conventional external cavity lasers are used, then data transmission is achieved, but laser phase noise increases vibration detection error
Solution Approach 1:
The patent changes the laser parameter by replacing conventional external cavity lasers with ultra-low linewidth lasers. This parameter change reduces the laser phase noise from typical values to ultra-low levels, thereby improving vibration detection accuracy while maintaining data transmission functionality. The ultra-low linewidth laser becomes the new operating parameter that simultaneously satisfies both data communication and precision vibration sensing requirements
3Stability of the object's composition
If wavelength dithering is applied, then channel stability is improved, but vibration sensing accuracy deteriorates due to intentional frequency modulation
Solution Approach 1:
The patent extracts and removes the wavelength dithering function from the system. By eliminating intentional frequency modulation, the system avoids the trade-off between channel stability and vibration sensing accuracy. Channel stability is maintained through other means while vibration sensing accuracy is preserved by not introducing artificial phase variations through dithering
4Ease of manufacture
If existing optical communication infrastructure is utilized, then deployment cost is reduced, but vibration detection functionality must be added without dedicated sensing channels
Solution Approach 1:
The patent makes existing optical communication transponders universal by enabling them to perform both data transmission and vibration sensing functions. This multi-functionality allows the system to utilize existing infrastructure for deployment (reducing cost) while simultaneously providing vibration detection capability (enhancing adaptability), without requiring dedicated sensing channels or separate infrastructure
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 vibration detection and localization with reduced noise interference and low overhead costs, using existing optical communication infrastructure, achieving performance comparable to dedicated vibration sensing systems.
Implementation Method 1
optical phase detected at remote end using a different local oscillator (LO) laser
Implementation Method 2
transponders utilizing coherent detection are widely deployed
Implementation Method 3
ultra-low linewidth lasers
Implementation Method 4
replacing conventional external cavity lasers (ECL) with more stable lasers exhibiting a lower frequency noise
Data Source
AI summary
Aspects of the present disclosure describe systems, methods. and structures for vibration detection using phase recovered from an optical transponder with coherent detection. Advantageously, our systems, methods, and structures leverage contemporary digital coherent receiver architecture in which various adaptive DSP operations performed to recover transmitted data track optical phase. The phase is extracted at low overhead cost, allowing a digital coherent transponder to perform vibration detection/monitoring as an auxiliary function to data transmission. Demonstration of vibration detection and localization based on the extraction of optical phase from payload-carrying telecommunications signal using a coherent receiver in a bidirectional WDM transmission system is shown and described.