Optical Semiconductor Waveguide Joining Plane Width Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing modulator-integrated semiconductor lasers experience high-order transverse mode scattering due to imperfect interfaces between the gain and light absorbing regions, leading to coupling loss and unreliable optical coupling, as the different materials used for these regions result in uneven refractive indices and widths.
Innovation Solution
An optical semiconductor device is designed with a first waveguide of embedded type, lattice-matched with InP, and a second waveguide of different refractive index, both with specific width regions and a joining plane where the width is equal to or smaller than 1.35 μm, to suppress high-order mode occurrence by controlling the width of the intermediate waveguide portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the waveguide width is increased to reduce coupling loss, then optical coupling reliability improves, but high-order transverse mode scattering occurs due to imperfect interfaces
Solution Approach 1:
The patent applies parameter changes by precisely controlling the waveguide width parameter. The waveguide width is set to 1.35 μm or less at the joining plane, which is a critical parameter change that prevents high-order mode generation while maintaining reliable optical coupling. This specific dimensional parameter resolves the contradiction between coupling reliability and mode scattering.
Solution Approach 2:
The patent implements local quality by creating different width regions within the waveguide structure. The waveguide has a narrower region (1.35 μm or less) at the joining plane where modes are suppressed, and wider regions (1.50 μm or more) in other areas where coupling efficiency is maintained. This spatial variation in width creates local quality differences that resolve the contradiction.
2Adaptability or versatility
If different materials are used for gain and light absorbing regions to optimize performance, then device functionality improves, but interface uniformity deteriorates due to different refractive indices
Solution Approach 1:
The patent applies local quality by creating a specific narrow width region (1.35 μm or less) at the joining plane where different materials with different refractive indices are joined. This localized geometric constraint compensates for the refractive index differences, maintaining interface uniformity in the critical coupling region while allowing material diversity for functional optimization in other regions.
Solution Approach 2:
The patent uses parameter changes by adjusting the waveguide width parameter to 1.35 μm or less at the joining plane. This dimensional parameter change compensates for the optical property differences between materials, maintaining effective interface uniformity for mode suppression while preserving the benefits of using different materials for gain and light absorbing regions.
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 reduces coupling loss and ensures reliable optical coupling by preventing high-order mode development, enhancing the modulation performance and stability of the semiconductor laser.
Implementation Method 1
a first waveguide of embedded type that includes a semiconductor and is lattice-matched with InP, the first waveguide having a region having a first constant width equal to or greater than 1.50 μm and a first region narrower than the region
Data Source
AI summary
An optical semiconductor device in which light having a wavelength of 1.25 μm or greater is waveguided, includes: a first waveguide of embedded type that includes a semiconductor and is lattice-matched with InP, the first waveguide having a region having a first constant width equal to or greater than 1.50 μm and a first region narrower than the region; and a second waveguide of embedded type that includes another semiconductor having a refractive index different from that of the first waveguide, the second waveguide having a region having a second constant width smaller than 1.50 μm and a second region wider than said region. The first waveguide and the second waveguide are joined at an intermediate waveguide portion. The intermediate waveguide portion includes the first region and the second region and a joining plane on which the first region and the second region are joined. The joining plane has a width equal to or smaller than 1.35 μm.