Tunable wavelength filter through bending control asymmetric single-mode grating fiber.

Area of Science:

• Optoelectronics
• Fiber Optics
• Materials Science

Background:

• Tunable wavelength filters are crucial components in optical communication and sensing systems.
• Existing filters often face limitations in tunability, stability, or fabrication complexity.
• Grating-based fiber filters offer a promising platform for developing compact and efficient optical devices.

Purpose of the Study:

• To propose and demonstrate a novel tunable wavelength filter.
• To investigate the relationship between fiber curvature and filter performance.
• To achieve wavelength tunability without compromising spectral characteristics.

Main Methods:

• Fabrication of an asymmetric single-mode grating fiber using anisotropic CF4 plasma etching.
• Characterization of the filter's spectral response under varying degrees of fiber bending.
• Analysis of reflection wavelength shift, rejection ratio, and spectral width.

Main Results:

• The proposed filter exhibits a linear shift in reflection wavelength with applied fiber curvature.
• A center wavelength shift of 3.5 nm was achieved at 1550 nm.
• Spectral rejection and half-power width remained largely constant across the observed wavelength shift.

Conclusions:

• An asymmetric grating fiber provides a viable method for creating tunable wavelength filters.
• Fiber bending offers a simple and effective mechanism for tuning the filter's central wavelength.
• The demonstrated filter maintains stable spectral properties, making it suitable for practical applications.