Tunable Laser Wavelength Switching via Etalon Preheating
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Solution Overview
Problem
Current tunable wavelength lasers experience prolonged downtime during wavelength switching, affecting user convenience and bandwidth efficiency in optical communications.
Innovation Solution
Incorporating a temperature control device and a wavelength detecting section with an etalon, the method suppresses light output, controls the etalon temperature to reach a target range for wavelength switching, and cancels suppression once the etalon temperature is within an allowable range, allowing for earlier restart of optical output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the etalon temperature is controlled to reach the target temperature before restarting light output, then the wavelength switching accuracy is improved, but the switching time is prolonged
Solution Approach 1:
The system performs preliminary temperature adjustment of the etalon to a preheat temperature (close to but not exactly the target temperature) before light output is suppressed. This preliminary action allows the etalon to be nearly ready for the target wavelength, reducing the waiting time after suppression while maintaining sufficient wavelength accuracy.
Solution Approach 2:
Instead of waiting for complete temperature stabilization at the target temperature before restarting light output, the system restarts output when the temperature reaches a sufficient threshold (preheat temperature). This partial completion of the temperature adjustment process is sufficient for practical wavelength accuracy while significantly reducing switching time.
2Reliability
If the light output is suppressed during wavelength switching, then the wavelength switching safety is improved, but the bandwidth utilization is reduced
Solution Approach 1:
The system performs preliminary temperature adjustment of the etalon to a preheat temperature before suppressing light output. This means that when light output is restarted after suppression, the etalon is already close to the target temperature, allowing faster resumption of bandwidth utilization while maintaining switching safety through the suppression period.
3Measurement precision
If the etalon temperature control is performed to reach exact target temperature, then the wavelength precision is improved, but the switching speed is reduced
Solution Approach 1:
The system determines that partial temperature adjustment to a preheat temperature (rather than complete adjustment to the exact target temperature) is sufficient for achieving the required wavelength precision in practical applications. This partial action significantly reduces switching speed penalties while maintaining adequate wavelength precision for optical communication purposes.
Solution Approach 2:
By performing preliminary temperature adjustment to a preheat temperature that is close to the target temperature, the system minimizes the remaining temperature adjustment needed after light output restarts. This preliminary action achieves most of the wavelength precision requirement before suppression ends, balancing precision and speed.
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 significantly reduces the time from initiating wavelength switching to restarting optical output, enhancing user convenience and bandwidth utilization by streamlining the wavelength switching process.
Implementation Method 1
a wavelength detecting section including an etalon, the temperature control device controls a temperature of the etalon, the wavelength detecting section identifies the output of the tunable wavelength laser by a ratio of intensity of light input to the etalon against intensity of light output from the etalon
Implementation Method 2
a temperature control device controls a temperature of the etalon... starting control of the temperature control device such that the temperature of the etalon becomes close to a second etalon temperature corresponding to the second wavelength
Data Source
AI summary
A method for switching a wavelength of a tunable wavelength laser, which is provided with a temperature control device for an etalon and a wavelength detecting section for identifying a wavelength of the laser by a front/back ratio of the etalon, the wavelength of the laser being set in a target wavelength on the basis of a detection result of the wavelength detecting section, and the method comprises: driving the laser at a first wavelength; suppressing output of light of the laser in response to a command indicating an optical output at a second wavelength; starting control of the temperature control device towards a second etalon temperature corresponding to the second wavelength; and before the etalon reaches the second etalon temperature, detecting that the etalon reaches a temperature range corresponding to an allowable wavelength range corresponding to the second wavelength, and cancelling the suppression of light in response thereto.