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Performance of a dual-mode-single-mode waveguide coupler as a modal filter
Applied Optics
|August 25, 2010
Summary
This study examines dual-mode waveguide couplers as filters. Their performance critically depends on the input
Area of Science:
- Optical Engineering
- Waveguide Technology
- Photonics
Background:
- Evanescent field couplers are key components in integrated optics.
- Modal filters are essential for controlling light propagation in waveguides.
- Dual-mode waveguides support multiple light modes simultaneously.
Purpose of the Study:
- To analyze the coupling characteristics of a dual-mode-single-mode evanescent field coupler.
- To evaluate its performance as a first-higher-order-mode filter.
- To understand the influence of input mode properties on filter performance.
Main Methods:
- Theoretical analysis of coupling mechanisms in evanescent field couplers.
- Numerical simulation of light propagation in dual-mode waveguides.
- Characterization of filter performance based on mode power and phase.
Main Results:
- Coupling characteristics were successfully obtained for the dual-mode-single-mode evanescent field coupler.
- Filter performance is critically dependent on the relative powers and phases of the input modes.
- High fractional power in the fundamental mode leads to phase-dependent filtering, compromising accurate higher-mode power measurement.
Conclusions:
- The studied evanescent field coupler can function as a modal filter.
- Accurate modal filtering requires careful control over the input conditions of the dual-mode waveguide.
- Phase sensitivity at high fundamental mode power limits its utility as a direct measure of higher-order modes.
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