Semiconductor Optical Device Mesa Structure for Wavelength-Dependent Loss Control
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Solution Overview
Problem
Semiconductor optical devices with small transverse mode diameters face challenges in optical coupling with external components due to high optical loss, and existing technologies struggle to adjust loss characteristics across a wide range of wavelengths in wavelength multiplex transmission systems.
Innovation Solution
A method for manufacturing semiconductor optical devices involves forming stacked semiconductor layers with specific mesa structures and etching techniques to create regions with varying optical absorption coefficients, allowing for adjustable wavelength-dependent optical loss, including the use of insulating films and selective etching to optimize light transition between upper and lower mesas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an optical waveguide with small transverse mode diameter is used, then transmission capacity is improved, but optical loss in coupling with external components increases
Solution Approach 1:
The patent introduces an intermediate structure (the mesa region with specific layer configuration) between the waveguide and external optical components. This intermediate structure acts as a mediator that gradually transitions the optical mode from the small diameter waveguide to the larger diameter external component, reducing optical loss through adiabatic coupling while maintaining the high transmission capacity of the small-mode waveguide.
Solution Approach 2:
The patent changes the physical parameters of the optical waveguide by creating a mesa structure with specific layer thicknesses and material compositions. By adjusting the dimensions and properties of the mesa region, the optical mode parameters are modified to achieve optimal coupling characteristics, transforming the rigid waveguide parameters into adjustable parameters that optimize both transmission capacity and coupling efficiency.
2Ease of manufacture
If conventional optical waveguides are used, then manufacturing is simple, but loss characteristics cannot be adjusted across wide wavelength ranges
Solution Approach 1:
The patent applies local quality by creating a mesa structure with spatially varying layer compositions and thicknesses. Different regions of the waveguide have different optical properties - the mesa region has specific layer configurations that provide wavelength-dependent loss characteristics, while other regions maintain standard waveguide properties. This allows the device to be manufactured using conventional processes while achieving wavelength-selective performance through localized structural variations.
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 reduces optical loss and allows for precise adjustment of loss characteristics across multiple wavelengths, enhancing the transmission capacity and efficiency of semiconductor optical devices in wavelength multiplex systems.
Implementation Method 1
In optical waveguides including a stacked semiconductor layer structure, the transverse mode diameter for guided light is as small as, for example, 1 μm or less
Implementation Method 2
forming stacked semiconductor layers with specific mesa structures and etching techniques to create regions with varying optical absorption coefficients, allowing for adjustable wavelength-dependent optical loss
Data Source
AI summary
A method for manufacturing a semiconductor optical device includes the steps of growing a stacked layer including lower and upper core layers, a first upper region including a non-doped layer, a second upper region including a p-type layer, and a cap layer; forming an upper mesa by etching the stacked layer; selectively etching the cap layer in the upper mesa on the first and second regions; forming a mask on the upper mesa in the second and third regions; and etching the upper mesa using the mask so as to form first to fourth mesa portions. The first and fourth mesa portions are formed by etching the first and second upper regions, and the second upper region and the cap layer, respectively. The second and third mesa portions are formed by etching the first and second upper regions, and the second upper region and the cap layer, respectively.