Ridge Waveguide Semiconductor Laser for Fast Wavelength Sweep
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Solution Overview
Problem
In gas measurement systems, performing wavelength sweep by changing the temperature of the heat sink is difficult and time-consuming, making high-speed measurement in a wide wavelength range challenging.
Innovation Solution
A semiconductor laser with a ridge waveguide structure and a heater arranged near the ridge portion, allowing for localized temperature control of the active layer to rapidly change the oscillation wavelength, reducing dependence on the heat capacities of the heat sink and Peltier element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the temperature of the heat sink is changed to perform wavelength sweep, then the oscillation wavelength can be changed, but the measurement speed becomes slow due to large heat capacity
Solution Approach 1:
The heater is positioned adjacent to the ridge portion and active layer to provide localized heating only where needed, rather than heating the entire heat sink. This localized approach reduces the thermal mass that needs to be heated, enabling faster wavelength sweep while maintaining precise temperature control of the laser cavity.
Solution Approach 2:
The heating function is separated from the heat sink structure by introducing an independent heater element. This allows the heater to be optimized for rapid heating without being constrained by the heat sink's large heat capacity, enabling independent control of the active layer temperature for fast wavelength tuning.
2Reliability
If a heat sink and Peltier element are used for temperature control, then temperature stabilization is achieved, but the device complexity and heat capacity increase
Solution Approach 1:
Temperature control is applied locally only to the ridge portion containing the active layer, rather than controlling the entire device temperature. This localized approach maintains wavelength stability while eliminating the need for large heat sink structures and complex Peltier element assemblies.
Solution Approach 2:
The temperature control function is extracted from the heat sink structure and implemented through a separate, miniaturized heater element. This separation allows the heat sink to be simplified or eliminated while maintaining temperature control capability through the dedicated heater.
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
Enables high-speed wavelength sweep and measurement across a wide range, allowing for rapid stabilization of the laser temperature and improved sensitivity in gas measurement.
Implementation Method 1
a heater arranged near the ridge portion
Implementation Method 2
an active layer, and a second cladding layer sequentially provided on a substrate
Implementation Method 3
a ridge portion arranged in a waveguide direction in the second cladding layer
Data Source
AI summary
A semiconductor laser of the present invention includes a first cladding layer, an active layer, and a second cladding layer sequentially provided on a substrate, includes a ridge portion arranged in a waveguide direction in the second cladding layer and a heater arranged near the ridge portion, and has an oscillation wavelength of 1.6 μm to 2.4 μm. Furthermore, a first guide layer and a second guide layer are provided between the first cladding layer and the active layer and between the active layer and the second cladding layer, respectively, a diffraction grating is provided at a boundary between the first cladding layer and the first guide layer or a boundary between the second cladding layer and the second guide layer, and an insulating film is provided on a surface of the second guide layer excluding the ridge portion, and the heater is arranged on the insulating film.