Automatic testing methods, systems, equipment, and products for current linewidth in narrow-linewidth lasers.

By adjusting the current with a preset step size and analyzing the frequency noise spectrum in a narrow-linewidth laser, and using an automatic inflection point identification algorithm to determine the optimal operating current, the problem of low measurement accuracy in traditional methods is solved, achieving high-precision and high-efficiency linewidth measurement.

CN121521422BActive Publication Date: 2026-06-30XUNSU XINYUAN TECHNOLOGY (SUZHOU) CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
XUNSU XINYUAN TECHNOLOGY (SUZHOU) CO LTD
Filing Date
2025-11-13
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

Traditional methods for measuring the linewidth of narrow-linewidth lasers suffer from low measurement accuracy, especially in sub-kHz and sub-hertz measurements. Long fiber delay introduces environmental noise, while short fiber delay causes weak signals to be submerged by system noise, resulting in distorted measurement results.

Method used

The laser injection current is adjusted by a preset step size, and frequency noise spectrum data is collected by a laser noise analyzer. The evolution characteristics of the frequency noise spectrum are analyzed by an automatic inflection point identification algorithm to determine the integral linewidth of the laser under the optimal operating current. The delay of long and short optical fibers is avoided by current scanning, thereby improving measurement accuracy and efficiency.

Benefits of technology

It achieves high-precision linewidth measurement of narrow-linewidth lasers, avoiding environmental noise introduced by long fiber delay and signal submersion caused by short fiber delay, thus improving measurement sensitivity and efficiency.

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Abstract

This invention discloses an automatic testing method, system, device, and product for the current linewidth of a narrow-linewidth laser. The invention acquires frequency noise spectrum data of the laser at different injection currents using a current scanning method with a preset step size, and calculates the linewidth of the laser at different injection currents based on this data. Finally, based on the integrated linewidth at different injection currents and using an automatic inflection point identification algorithm, the evolution characteristics of the laser's frequency noise spectrum under different injection currents are analyzed, thereby determining the integrated linewidth of the laser at its optimal operating current. Therefore, this invention provides a new linewidth measurement technology. Compared to traditional delay heterodyne methods and improved zero-beat schemes, it eliminates the need for long / short laser delays, thus avoiding the environmental noise introduced by long fiber delays and the problem of weak signals being submerged by system noise due to short fiber delays, thereby improving measurement accuracy.
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