Optical Data Transmission Links Beat Interference Control
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Solution Overview
Problem
In passive optical networks, optical beat interference occurs due to multiple optical sources transmitting simultaneously, causing signal degradation at the receiver, which is exacerbated by the nonlinearity of photodiodes and requires costly laser regulation or precise temperature control to maintain wavelength gaps, posing a challenge in green technology.
Innovation Solution
A method for concurrently operating multiple optical data transmission links using independent wavelengths, where measuring equipment identifies signal quality degradation and interfering links, and adjusts operation parameters such as transmit power and transfer rate to reduce interference, without shifting wavelengths, thereby adapting to signal quality reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gap between two neighboring wavelengths is kept broad to reduce beat interference, then signal quality is improved, but laser cost increases and energy consumption increases due to precise temperature control requirements
Solution Approach 1:
The patent changes the parameter being controlled from wavelength spacing to transmit power level. Instead of maintaining a fixed wavelength gap, the system dynamically adjusts the transmit power of individual optical sources based on detected interference conditions, thereby eliminating the need for precise temperature control and high energy consumption while maintaining signal quality
Solution Approach 2:
The patent introduces dynamic adjustment of transmit power levels in response to real-time interference detection. The control unit continuously monitors for beat interference and adapts the power levels of affected sources, replacing the static approach of fixed wavelength spacing with a dynamic power control mechanism that responds to actual network conditions
2Reliability
If the gap between two neighboring wavelengths is kept broad to reduce beat interference, then signal quality is improved, but device complexity and cost increase due to costly lasers with precise temperature control
Solution Approach 1:
The patent shifts the control parameter from wavelength (requiring complex temperature control) to transmit power level (controllable via simple electronic adjustment). This parameter change simplifies the laser regulation mechanism while maintaining the ability to manage interference effectively
Solution Approach 2:
The patent enables the use of standard, less expensive laser sources that do not require precise temperature control by implementing software-based power management. The system compensates for the lack of physical precision through intelligent power adjustment, replacing costly precision-controlled hardware with simpler components
3Reliability
If transmit power is reduced to mitigate beat interference, then signal quality is improved, but transfer rate must be reduced to adapt to signal quality reduction
Solution Approach 1:
The patent applies partial power reduction only to the specific optical sources causing interference, rather than reducing power across the entire system. The control unit selectively adjusts power levels of affected sources while maintaining full power for non-interfering sources, thereby mitigating interference locally without unnecessarily reducing overall system productivity
Solution Approach 2:
The patent implements local power adjustment for specific interfering sources rather than global power reduction. Each optical source's power is independently controlled based on its specific interference conditions, allowing the system to maintain high transfer rates for non-interfering channels while only reducing power where necessary to eliminate beat interference
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
This approach effectively mitigates optical beat interference by reducing transmit power and transfer rate, ensuring stable signal reception without the need for costly laser regulation or precise temperature control, thus enhancing the operational efficiency and sustainability of optical data transmission systems.
Implementation Method 1
Photodiodes are producing as electrical output the lowpass filtered square of the incident optical fields
Implementation Method 2
The origin of such interference is the nonlinearity of receiver diodes, normally photo diodes, that result in beat interference between signals with neighboring wavelengths
Data Source
Figure 1
AI summary
The invention relates to a method for concurrently operating several optical data transmission links using different independent optical wavelengths via a common medium with a common receive side, in which on occurrence of symptoms for failures of either of the transmission links it is checked, whether signal quality degradation by interfering optical wavelengths occurs, wherein on occurrence of such symptoms it is checked from which of the other transmission links such interference depends, and wherein with at least one of the interfering transmission links the operation parameters except for the wavelengths are changed such that a reduction of the interference is to be expected, to an optical data transmission system, and to a control unit.