Tunable Wavelength Laser Testing via Etalon FSR Measurement
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Solution Overview
Problem
Existing tunable wavelength laser technologies face errors in light transmission characteristics due to deviations in etalon components or assembly processes, leading to increased temperature control ranges, especially in gridless control scenarios.
Innovation Solution
A method for testing a tunable wavelength laser device that involves measuring the free spectral range interval of the etalon, acquiring driving conditions by tuning the wavelength to target values within this interval, and storing these conditions in memory to suppress errors in light transmission characteristics, thereby reducing the temperature control range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature control range is increased to correct etalon errors, then wavelength accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by measuring and storing the actual free spectral range (FSR) values of the etalon at different temperatures before operation. During operation, the system retrieves pre-stored driving conditions corresponding to the measured FSR, eliminating the need for real-time temperature adjustment and reducing power consumption while maintaining wavelength accuracy.
Solution Approach 2:
The patent changes the parameter storage approach from storing fixed temperature-compensated values to storing driving conditions (current, voltage, or other control parameters) directly associated with measured FSR values. This allows the system to adapt to etalon variations by selecting appropriate driving conditions based on actual measurements, improving wavelength accuracy without requiring broad temperature control ranges.
2Measurement precision
If temperature control range is increased to correct etalon errors, then wavelength accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts the temperature control function from the wavelength control process. Instead of using temperature adjustment as the primary method for wavelength calibration, the system separates temperature control (maintaining stable operation) from wavelength calibration (achieved through FSR measurement and driving condition selection), thereby simplifying the temperature control system while maintaining wavelength accuracy.
Solution Approach 2:
The patent introduces FSR measurement and driving condition lookup tables as intermediaries between the etalon and the wavelength control mechanism. Rather than directly controlling temperature to correct errors, the system measures FSR, retrieves appropriate driving conditions from stored data, and applies these conditions, creating a simplified control pathway that reduces device complexity.
3Adaptability or versatility
If gridless control is implemented for non-ITU-T wavelengths, then wavelength selection flexibility is improved, but temperature control range must be increased
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing driving conditions for multiple wavelength points across the etalon's tuning range, including non-ITU-T grid wavelengths. During gridless control operation, the system measures the current FSR and retrieves the appropriate pre-stored driving condition, enabling flexible wavelength selection without requiring increased temperature control range.
Solution Approach 2:
The patent changes from storing fixed wavelength values to storing driving conditions that correspond to measured FSR values. This allows the system to accurately control wavelengths beyond ITU-T grids by selecting driving conditions based on actual FSR measurements, maintaining temperature control range while improving wavelength selection flexibility.
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 minimizes the temperature control range of the etalon, reducing power consumption and improving the precision of automatic frequency control, while allowing for accurate wavelength selection beyond ITU-T grid wavelengths.
Implementation Method 1
a wavelength sensing unit having an etalon... measuring a free spectral range interval of the etalon
Implementation Method 2
a tunable wavelength laser... acquiring a driving condition by tuning a wavelength to a target value
Data Source
AI summary
A method for testing a tunable wavelength laser device, which can suppress any error of light transmission characteristics of an etalon, and a tunable wavelength laser device are provided. The method for testing a tunable wavelength laser device is a method for testing a tunable wavelength laser device including a tunable wavelength laser and a wavelength sensing unit having an etalon. The testing method includes a first step of measuring a free spectral range interval of the etalon, a second step of acquiring a driving condition by tuning a wavelength to a target value provided between a top and a bottom of the free spectral range interval, and a third step of storing the driving condition in a memory.