Temperature-Switched EA Modulators for Stable Laser Wavelengths
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Solution Overview
Problem
Existing semiconductor laser devices face challenges in maintaining a stable balance between optical output and extinction ratio due to temperature-dependent fluctuations in oscillation wavelength and absorption peak wavelength, leading to potential failures in meeting strict wavelength standards.
Innovation Solution
An optical semiconductor device is designed with multiple EA modulators having different absorption peak wavelengths, a temperature detector, and a selection control circuitry that switches EA modulators based on temperature, reducing the range of oscillation wavelength fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single DFB laser and EA modulator combination is used, then the device structure is simple, but the oscillation wavelength fluctuates widely with temperature changes
Solution Approach 1:
The patent divides the EA modulator into multiple units (first EA modulator and second EA modulator) with different absorption peak wavelengths. Each EA modulator unit is paired with the single DFB laser to form separate laser units. This segmentation allows the system to maintain a simple overall structure while achieving stable oscillation wavelength through selective activation of appropriate laser units based on temperature conditions.
2Stability of the object's composition
If multiple DFB lasers with different oscillation wavelengths are used to follow temperature changes, then the oscillation wavelength stability is improved, but the wavelength range becomes too wide for strict wavelength standards
Solution Approach 1:
The patent applies local quality by designing EA modulators with specific absorption peak wavelengths that correspond to different temperature ranges. The first EA modulator has an absorption peak wavelength suited for lower temperatures, while the second EA modulator has an absorption peak wavelength suited for higher temperatures. This allows each laser unit to maintain optimal performance in its designated temperature range, ensuring the oscillation wavelength stays within strict standards while still adapting to temperature changes.
3Manufacturing precision
If the EA modulator absorption peak wavelength is matched to the DFB laser oscillation wavelength at a specific temperature, then the detuning amount is optimized for that temperature, but performance degrades when temperature fluctuates
Solution Approach 1:
The patent implements dynamics by making the system adaptable to temperature changes through multiple laser units with different characteristics. The selection control circuitry dynamically selects which laser unit to activate based on the detected temperature. This dynamic adaptation ensures that the detuning amount remains optimized across varying temperature conditions, maintaining performance consistency and reliability while preserving the precision achieved during manufacturing for specific temperature points.
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 configuration effectively minimizes the range of oscillation wavelength changes, ensuring stable performance across a wide temperature range and meeting strict wavelength standards, particularly suitable for outdoor use.
Implementation Method 1
a temperature detector configured to detect a temperature of the laser or the plurality of EA modulators
Implementation Method 2
a plurality of EA modulators to which an output of the laser is connected on an input side and which have absorption peak wavelengths different from each other
Data Source
AI summary
An optical semiconductor device according to the present disclosure includes at least one laser, a plurality of EA modulators to which an output of the laser is connected on an input side and which have absorption peak wavelengths different from each other, a multiplexer to which outputs of the plurality of EA modulators are connected on an input side and to which a waveguide is connected on an output side, a temperature detector configured to detect a temperature of the laser or the plurality of EA modulators and a selection control circuitry configured to switch an EA modulator to operate among the plurality of EA modulators in accordance with a detected temperature of the temperature detector.