Single-mode and multimode all-fiber directional couplers for WDM

Area of Science:

• Optoelectronics
• Fiber Optics
• Telecommunications

Background:

• Wavelength Division Multiplexing (WDM) is crucial for increasing fiber optic communication capacity.
• Existing WDM technologies often involve complex optical components like lenses.
• There is a need for compact, efficient WDM devices with minimal optical losses and polarization effects.

Purpose of the Study:

• To describe the theory, production, and properties of novel WDM devices based on beam splitting.
• To investigate the performance characteristics of these WDM devices for both single-mode and multimode fiber applications.
• To analyze the impact of various parameters on WDM coupler performance, including fiber type, light source, and channel configuration.

Main Methods:

• Development of WDM modules utilizing an edge interference filter on an oblique polished fiber end face.
• Design considerations for both single-mode and multimode fiber compatibility, including core diameter requirements for single-mode coupling.
• Characterization of device performance based on fiber type, light sources (laser diodes, LEDs), channel separation, and transmission/reflection modes.

Main Results:

• The developed WDM devices are lensless and exhibit minimal polarizing effects.
• Insertion losses range from 0.7 to 2 dB.
• Far-end crosstalk attenuation is between 11 and 22 dB, while near-end crosstalk attenuation exceeds 40 dB.

Conclusions:

• The beam splitting principle enables the creation of efficient, lensless WDM devices.
• These devices demonstrate competitive performance metrics, including low insertion loss and high crosstalk attenuation.
• The characterized properties provide valuable data for the design and implementation of WDM systems in optical networks.