Optical Amplifier Output Power Decrease Detection Method
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Solution Overview
Problem
Existing methods fail to effectively determine a decrease in optical output power of optical fiber lasers during both continuous-wave oscillation and modulation operations, particularly due to limitations in detecting deterioration in non-fixed optical outputs and requiring multiple imaging means for high-density packaging.
Innovation Solution
A method that calculates the ratio of time-averaged optical output power to an expectation value, using a modified expectation value for modulation operations, and varies thresholds based on detected current, allowing for determination of optical output power decrease in optical fiber laser systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed set point method is used to detect optical output power decrease, then the detection is simple, but it cannot be applied to modulation operations where optical output is not fixed
Solution Approach 1:
The patent transforms the fixed set point method into a dynamic expectation value calculation method. Instead of comparing actual output to a fixed set point, the system calculates an expectation value based on the integrated pumping light output over time. This dynamic approach allows the detection method to adapt to both continuous-wave and modulation operations, resolving the contradiction between simplicity and versatility.
2Reliability
If imaging means are used to detect laser beam leakage, then failure detection is possible, but multiple imaging means are required for high-density packaging and space is needed around the device
Solution Approach 1:
The patent extracts the detection function from external imaging means and integrates it into the existing control system. By using the existing optical detectors and control electronics already present in the optical fiber laser apparatus, the system can detect output power decreases without adding separate imaging devices. This eliminates the need for multiple imaging means and reduces spatial requirements, resolving the contradiction between reliability and device complexity.
3Reliability
If optical output power is monitored continuously, then deterioration can be detected early, but the measurement system becomes more complex
Solution Approach 1:
The patent implements a self-service detection mechanism where the system uses its own existing components for monitoring. The control system utilizes the existing optical detectors and pumping light control infrastructure to calculate the expectation value and detect output power decreases. This self-service approach enables continuous monitoring without requiring additional complex measurement equipment, resolving the contradiction between reliability and device complexity.
Data Source
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AI summary
A current Ii supplied to a pumping light source 20 is detected and time-averaged with a predetermined time constant to calculate a time-averaged current Iav. An optical output power Pi outputted from an amplifying optical fiber 12 is detected and time-averaged with the predetermined time constant to calculate a time-averaged optical output power Pav. A reference optical output power Pr and a reference current Ir supplied to the pumping light source 20 when the reference optical output power Pr is outputted from an optical fiber laser apparatus 1 are used to calculate an optical output power expectation value Pex = Iav × Pr / Ir. The time-averaged optical output power Pav and the optical output power expectation value Pex are compared with each other to determine a decrease of an optical output power of the optical amplifier apparatus 1 based on the comparison result.