Low through channel loss wavelength multiplexer using multiple transmission volume Bragg gratings

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Wavelength multiplexers are crucial for increasing fiber optic communication capacity.
• Volume Bragg gratings offer a compact and efficient method for wavelength selection.
• Minimizing insertion loss and interchannel crosstalk is essential for high-performance multiplexers.

Purpose of the Study:

• To design and demonstrate a novel wavelength multiplexer utilizing multiple volume Bragg gratings.
• To achieve low through-channel loss and high interchannel crosstalk suppression.
• To analyze the impact of beam diameter on device performance.

Main Methods:

• Fabrication of multiple transmission volume Bragg gratings within a single photosensitive glass region.
• Apodization of gratings to control diffraction efficiency and minimize crosstalk.
• Experimental validation of a two-channel multiplexer at 1310 nm and 1550 nm.
• Analysis of angular dispersion effects on device performance.

Main Results:

• Achieved a through-channel loss of less than 0.5 dB.
• Demonstrated excellent agreement (within 0.2 dB) between simulated and experimental peak diffraction efficiency.
• Reduced interchannel crosstalk from 13.5 dB to 41.5 dB using grating apodization.
• Experimental through-channel loss measured at 0.6 dB.

Conclusions:

• The proposed volume Bragg grating multiplexer design is effective for efficient optical signal routing.
• Grating apodization significantly improves crosstalk performance, crucial for dense wavelength-division multiplexing systems.
• The design shows promise for practical applications in optical communication networks.