Vector coupled-mode analysis of coupling between two identical optical fiber cores

Area of Science:

• Optics and Photonics
• Electromagnetism
• Wave Propagation

Background:

• Coupled-mode theory is essential for analyzing light propagation in multi-core optical fibers.
• Understanding array modes and polarization states is crucial for advanced fiber optic applications.
• Existing theories may have limitations, especially in strongly guiding fiber regimes.

Purpose of the Study:

• To evaluate the accuracy of vector coupled-mode analysis for two single-mode coupled optical fiber cores.
• To compare the performance of conventional coupled-mode theory with a recently formulated new theory.
• To investigate the prediction of array modes across different polarization states and guiding regimes.

Main Methods:

• Application of vector coupled-mode analysis using exact HE(11) modes.
• Examination of strongly guiding and weakly guiding fiber scenarios.
• Consideration of various array modes and their polarization states.

Main Results:

• Full-wave coupled-mode calculations accurately predict array-mode propagation constants beyond the weakly guiding regime.
• Conventional coupled-mode theory, when applied in vectorial form, yields satisfactory results.
• The study validates the applicability of these theoretical frameworks for complex fiber systems.

Conclusions:

• Vector coupled-mode analysis provides reliable predictions for array-mode propagation constants in strongly guiding fibers.
• The vectorial form of conventional coupled-mode theory remains a viable and accurate approach for two-core fiber systems.
• This research enhances the theoretical understanding of light propagation in coupled optical fibers.