Laser Side Mode Suppression Ratio Control via Bias and Attenuation
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Solution Overview
Problem
Current laser manufacturing processes face challenges in achieving high Side Mode Suppression Ratio (SMSR) due to strict manufacturing tolerances, leading to low throughput and high non-conformance rates, as not all fabricators can meet these tolerances, resulting in suboptimal spectral quality and increased yield losses.
Innovation Solution
A system comprising a laser, an SMSR sensor, a Variable Optical Attenuator (VOA), and a logic controller that adjusts the laser bias and VOA attenuation levels based on SMSR and average optical power readings to maintain spectral quality and increase SMSR, allowing for wider material flexibility and improved spectral deficiencies correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If stricter manufacturing tolerances are employed during laser fabrication to achieve higher SMSR, then spectral quality is improved, but production throughput decreases and yield losses increase
Solution Approach 1:
The patent applies preliminary action by measuring the SMSR of each laser device during the fabrication process and adjusting the current configuration before the device is completed. This allows manufacturers to compensate for variations in laser characteristics early in the production process, ensuring high SMSR performance without requiring extremely tight manufacturing tolerances, thereby maintaining high production throughput and yield.
2Manufacturing precision
If stricter manufacturing tolerances are employed during laser fabrication to achieve higher SMSR, then spectral quality is improved, but in-field non-conformance rates increase
Solution Approach 1:
The patent implements feedback by measuring the SMSR of each laser device during fabrication and using this measurement to adjust the operating current configuration. This closed-loop approach ensures that each device is optimized to meet the minimum SMSR specification, reducing variability and improving reliability in the field. Devices that would otherwise fail due to manufacturing variations are compensated for through current adjustment, lowering in-field non-conformance rates.
3Manufacturing precision
If stricter manufacturing tolerances are employed during laser fabrication, then SMSR performance is improved, but fabrication flexibility and material choices are reduced
Solution Approach 1:
The patent applies parameter changes by adjusting the operating current of the laser device based on measured SMSR values. This allows manufacturers to use a broader range of materials and fabrication processes with relaxed tolerances, as the final SMSR performance is optimized through electrical parameter adjustment rather than relying solely on precise physical manufacturing parameters. This significantly increases fabrication flexibility and material choices.
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 solution enhances the operational range of lasers with high SMSR, meeting performance specifications while allowing for more flexible fabrication and reducing in-field non-conformance rates, thereby improving the overall efficiency and yield of optical device production.
Implementation Method 1
generating a carrier wave via a laser
Implementation Method 2
measuring a Side Mode Suppression Ratio (SMSR) of the carrier wave
Implementation Method 3
adjusting at least one of a driving voltage or current for the laser and an attenuation level of the carrier wave
Data Source
AI summary
Laser Side Mode Suppression Ratio (SMSR) control is provided via a logic controller configured to measure an SMSR of a carrier wave upstream of a modulator and measure an Average Optical Power (AOP) of the carrier wave downstream of the modulator; transmit a bias voltage based on the SMSR and the AOP to a laser driver for a laser generating the carrier wave; and transmit an attenuation level based on the SMSR and the AOP to a Variable Optical Attenuator (VOA) upstream of the modulator. In various embodiments the attenuation level and bias voltage can rise or fall together, or one may rise and one may fall to ensure the output optical signal meets specified SMSR and AOP values.