Ultra-selective flexible add and drop multiplexer using rectangular optical filters based on stimulated Brillouin...

Area of Science:

• Optical Engineering
• Telecommunications
• Photonics

Background:

• Flexible optical network architectures are crucial for managing increasing data traffic.
• Reconfigurable optical add-drop multiplexers (ROADMs) are key components for dynamic wavelength routing.
• Existing ROADM technologies face challenges in achieving high spectral selectivity and tunability.

Purpose of the Study:

• To demonstrate an ultra-selective, flexible, and reconfigurable add-drop multiplexer (ROADM) structure.
• To enable efficient separation and aggregation of multi-band orthogonal frequency-division multiplexing (MB-OFDM) signals.
• To achieve fine spectral granularity and utilize narrow guard bands.

Main Methods:

• Utilized rectangular optical filters based on the stimulated Brillouin effect (SBS) in fiber.
• Implemented two electrical feedback pump control approaches for tunable filter bandwidth (100 MHz to 3 GHz).
• Tested the ROADM performance with MB-OFDM signals in Quadrature Phase-Shift Keying (QPSK) and 16-Quadrature Amplitude Modulation (16-QAM) formats.

Main Results:

• Achieved ~2-GHz spectral granularity and a 300-MHz guard band for MB-OFDM signals.
• The SBS-based ROADM exhibited steep filter edges and ~1-dB passband ripple.
• Demonstrated a low insertion loss penalty of ~0.7 dB for QPSK signals and acceptable performance for 16-QAM signals.

Conclusions:

• The proposed SBS-ROADM offers ultra-selectivity and flexibility for optical networks.
• The tunable bandwidth and fine spectral granularity are suitable for advanced MB-OFDM signal processing.
• This technology presents a promising solution for next-generation flexible optical communication systems.