Semiconductor Optical Amplifier Expanded Width for Gain Stability
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Solution Overview
Problem
Conventional integrated semiconductor laser elements experience increased deviation in output intensity with respect to wavelength when achieving higher-power output, particularly at high temperatures, which affects their performance in DWDM optical communication systems.
Innovation Solution
The integrated semiconductor laser element incorporates semiconductor lasers with active layers and a semiconductor optical amplifier, where the active layers have the same thickness and composition, and the amplifier includes an expanded width portion to match the gain peak wavelength, suppressing band filling phenomena and maintaining gain peak alignment even at high power and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output power of the integrated semiconductor laser element is increased to support higher data rates and compensate for modulator loss, then the transmission bandwidth and data rate are improved, but the wavelength dependency of the output intensity increases, causing deviation in output intensity across different wavelengths
Solution Approach 1:
The patent changes the physical parameters of the semiconductor optical amplifier by forming an expanded width portion to increase the active layer width. This parameter change increases the modal gain and adjusts the gain peak wavelength, thereby compensating for the wavelength-dependent intensity deviation that occurs at high output powers, while maintaining stable operation across the wavelength band.
2Use of energy by stationary object
If the operating temperature is increased to reduce cooling power consumption, then the power consumption is reduced, but the gain peak wavelength of the semiconductor optical amplifier shifts due to band filling phenomenon, increasing wavelength dependency
Solution Approach 1:
The patent performs preliminary action by pre-designing the expanded width portion in the semiconductor optical amplifier before operation. This structural preparation compensates in advance for the band filling phenomenon that occurs at high temperatures, allowing the gain peak wavelength to remain stable even when operating without active cooling, thus reducing power consumption while maintaining wavelength stability.
3Reliability
If the active layer width is increased to increase modal gain and suppress band filling phenomenon, then the gain peak wavelength stability is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by forming the expanded width portion only in specific regions of the semiconductor optical amplifier where it is most needed to suppress band filling phenomenon. The active layer width is locally increased in the expanded width portion while maintaining the original width in other portions, thereby achieving gain stability without unnecessarily increasing overall device complexity.
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 achieves high-power output with reduced wavelength-dependent intensity deviation, enabling stable operation in high-temperature conditions and supporting data rates of 100 Gbps in DWDM optical communication systems.
Implementation Method 1
a semiconductor optical amplifier that amplifies output light from the optical coupler
Implementation Method 2
the semiconductor optical amplifier includes an equal width portion formed on a side of the optical coupler to guide the output light in a single mode
Data Source
AI summary
An integrated semiconductor laser element includes: semiconductor lasers that oscillate at different oscillation wavelengths from one another, each laser oscillating in a single mode; an optical coupler; and a semiconductor optical amplifier. At least one of active layers of the semiconductor lasers and an active layer of the semiconductor optical amplifier have a same thickness and a same composition that is set to have a gain peak wavelength near a center of a wavelength band formed by the oscillation wavelengths. The semiconductor optical amplifier includes: an equal width portion formed on a side of the optical coupler to guide light in a single mode; and an expanded width portion formed on a light output side. The width of the expanded width portion is set according to a total thickness of well layers of the active layer of the semiconductor optical amplifier.