Optical Waveguide Ridge Structure for Light Confinement
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Solution Overview
Problem
Optical waveguide devices with ridge portions suffer from light leakage and increased propagation loss due to tipping at the edges, which is exacerbated by the depth and width of the grooves and protuberances, making it difficult to confine light effectively.
Innovation Solution
The optical waveguide device features a ferroelectric layer with a ridge portion and protuberances or step portions, where the inner and outer grooves are strategically designed with specific depth and width parameters to minimize light leakage and reduce propagation loss, with the ridge portion width between 6.6 μm and 8.5 μm, and the distance between protuberances or step portions optimized to enhance light confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the groove is made deeper to strengthen the confinement of light, then the light confinement is improved, but tipping occurs at the edges of the ridge portion resulting in increased propagation loss
Solution Approach 1:
The invention optimizes specific parameters including the groove depth (0.5-2.0 μm), ridge portion width (3.0-6.5 μm), and protuberance dimensions to achieve the optimal balance between light confinement and prevention of tipping-induced propagation loss
Solution Approach 2:
The invention introduces protuberances with specific dimensions on both sides of the ridge portion to locally modify the structure, providing enhanced light confinement at the edges while preventing tipping through the carefully designed geometry of the protuberances
2Reliability
If the width of the ridge portion is reduced to decrease mode size, then the light confinement is improved, but the density of light increases making the influences of tipping considerable
Solution Approach 1:
The invention determines the optimal ridge portion width range (3.0-6.5 μm) that balances mode size reduction for light confinement with maintaining sufficient width to reduce light density and minimize tipping influences
Solution Approach 2:
The protuberances act as intermediary structures that provide local support and optical confinement at the ridge edges, enabling the use of narrower ridge portions without suffering from tipping-induced propagation loss
3Productivity
If deeper grooves are formed to strengthen lateral confinement of light, then the propagation efficiency is improved, but the tipping at edges increases during processing
Solution Approach 1:
The invention specifies optimal groove depth parameters (0.5-2.0 μm) that provide sufficient lateral confinement for high propagation efficiency while remaining shallow enough to prevent tipping during the groove formation process
Solution Approach 2:
The protuberances are formed beforehand on both sides of the ridge portion to provide structural support and prevent tipping during subsequent groove formation and processing steps
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 significantly reduces light leakage and propagation loss by optimizing the mode size and confinement within the ridge portion, preventing the cut-off state and scattering that occurs with smaller widths and deeper grooves, thereby improving overall propagation efficiency.
Implementation Method 1
A layer 3, made of MgO-doped lithium niobate for example and a supporting body 1 are adhered through an adhesive layer 2. A pair of elongate grooves 6, parallel with each other, are formed in the layer 3, so that the grooves 6 form a ridge portion 5. The ridge portion 5 and grooves 6 together form an optical waveguide structure 4, so that the ridge portion 5 functions as a three-dimensional or channel type optical waveguide.
Implementation Method 2
so-called ridge shaped optical waveguides can improve the confinement of light to provide a high efficiency of controlling light
Implementation Method 3
Non-linear optical crystals, such as lithium niobate or lithium tantalite single crystal, have a high second-order non-linear optical constant. It is thus possible to realize a quasi-phase matched (QPM) type second harmonic generation (SHG) device, by providing a periodic polarization domain inversion structure in the crystal.
Implementation Method 4
realize a quasi-phase matched (QPM) type second harmonic generation (SHG) device, by providing a periodic polarization domain inversion structure in the crystal
Data Source
AI summary
An optical waveguide device includes a ferroelectric layer having a thickness of 4 μm-7 μm; a supporting body; and an adhesive layer adhering a bottom face of the ferroelectric layer and supporting body. The ferroelectric layer includes a ridge comprising a channel optical waveguide, first and second protuberances on opposite sides of the ridge, inner grooves between the ridge and protuberances, respectively, and outer grooves outside of the protuberances, respectively. The outer groove is deeper than the inner groove. The ridge portion has a width of 6.6 μm-8.5 μm, a distance of an outer edge of the first protuberance and an outer edge of the second protuberance is 8.6 μm-20 μm, the inner groove has a depth of 2.0 μm-2.9 μm, and the outer groove has a depth of 2.5 μm-3.5 μm.