All-optical modulation-transparent wavelength multicasting in a highly nonlinear fiber Sagnac loop mirror

Area of Science:

• Optical Communications
• Nonlinear Optics
• Fiber Optics

Background:

• Wavelength multicasting is crucial for increasing optical network capacity.
• Four-wave mixing (FWM) in highly nonlinear fibers (HNLF) is a key enabling technology.
• Existing FWM schemes can suffer from signal degradation when channels overlap with idlers.

Purpose of the Study:

• To demonstrate an all-optical wavelength multicasting scheme using a Sagnac loop mirror.
• To improve signal quality and reduce power penalties in multicasting.
• To assess the performance with different numbers of pump lasers and modulation formats.

Main Methods:

• Utilizing four-wave mixing (FWM) within a highly nonlinear fiber (HNLF) Sagnac loop mirror.
• Employing two and three pump lasers to generate six and ten 10-Gb/s multicast channels, respectively.
• Testing the scheme with both on-off shift keying (OOK) and differential phase-shift keying (DPSK) signals.

Main Results:

• Successful demonstration of all-optical wavelength multicasting with clear eye diagrams, even with overlapping pump-idler wavelengths.
• Generation of six and ten 10-Gb/s ITU-grid compliant multicast channels.
• Achieved a maximum power penalty of less than 3.5 dB for all multicast channels.
• Observed up to 1.2 dB power penalty improvement compared to a non-loop configuration.

Conclusions:

• The HNLF Sagnac loop mirror configuration offers a robust solution for all-optical wavelength multicasting.
• This scheme effectively mitigates signal degradation issues present in non-loop FWM systems.
• The demonstrated technique supports high-speed, high-density optical signal distribution for future networks.