Optical Module Wavelength Locking Under SOA Heat Drift
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Solution Overview
Problem
In wavelength division multiplexing communication, the lock wavelength drifts due to heat generated by semiconductor optical amplifiers when placed on the same temperature controller as the etalon filter, affecting the accuracy of optical signal transmission.
Innovation Solution
An optical module configuration that includes a laser light source unit, a wavelength filter with a periodic transmission characteristic, a temperature controller, and a control device that adjusts the wavelength of the laser beam and the filter based on the intensity of the laser beam transmitted through the filter, using calibration methods to account for changes in the heat generating body's current value, thereby maintaining wavelength stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the heat generating body (semiconductor optical amplifier) is placed on the same temperature controller as the wavelength filter, then the device complexity is reduced and space is saved, but the wavelength drift occurs due to heat generation affecting the filter's transmission characteristic
Solution Approach 1:
The patent implements a feedback control mechanism where the control device monitors the transmission characteristic of the wavelength filter and dynamically adjusts the target wavelength of the laser beam and/or the target transmission characteristic of the filter based on the heat generating body's current value. This closed-loop feedback system compensates for wavelength drift caused by thermal effects, resolving the contradiction between device integration and wavelength stability.
Solution Approach 2:
The patent changes the operational parameters (target wavelength and/or target transmission characteristic) dynamically based on the heat generating body's current state. By adjusting these parameters in response to thermal conditions, the system maintains accurate wavelength control despite the integrated configuration causing thermal interference.
2Productivity
If the optical power is increased to improve signal transmission, then the communication efficiency is improved, but the wavelength drift increases due to greater heat generation from the semiconductor optical amplifier
Solution Approach 1:
The control device uses feedback control to monitor and adjust the wavelength parameters based on the heat generating body's current value, which correlates with optical power levels. This allows the system to maintain wavelength accuracy across varying power conditions, enabling high communication efficiency without sacrificing wavelength stability.
Solution Approach 2:
The patent makes the wavelength control parameters dynamic rather than static. The target wavelength and/or target transmission characteristic are adjusted in real-time based on the operational state (current value) of the heat generating body, allowing the system to adapt to changing thermal conditions caused by varying optical power requirements.
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
Prevents wavelength drift even when optical power changes, ensuring accurate wavelength control and stable optical signal transmission by dynamically adjusting the target values for the laser beam and wavelength filter based on the heat generating body's current value.
Implementation Method 1
a temperature controller on which the wavelength filter is placed and that adjusting a temperature of the wavelength filter
Implementation Method 2
controlling the transmission characteristic of the wavelength filter based on an intensity of the laser beam transmitted through the wavelength filter
Implementation Method 3
a laser light source unit emitting a laser beam
Implementation Method 4
a wavelength filter having a periodical transmission characteristic with respect to a wavelength of light
Implementation Method 5
a heat generating body placed on the temperature controller
Data Source
AI summary
A method for controlling a wavelength of an optical module, includes: a laser light source unit emitting a laser beam; a wavelength filter having a periodical transmission characteristic with respect to a wavelength of light; a temperature controller on which the wavelength filter is placed and that adjusting a temperature of the wavelength filter; a heat generating body placed on the temperature controller; and a control device controlling the wavelength of the laser beam emitted from the laser light source unit and control the transmission characteristic of the wavelength filter based on an intensity of the laser beam transmitted through the wavelength filter, the method including changing at least one of a target value of the wavelength control of the laser beam and a target value of the control of the wavelength filter based on a current value of the heat generating body.