Digital-filter-aided crosstalk-mitigation for a high spatial resolution AWGR-based 2D IR beam-steered indoor optical...

Area of Science:

• Optical Wireless Communication (OWC)
• Infrared Beam-Steering Technology
• Digital Signal Processing

Background:

• Increasing demand for wireless connectivity drives innovation in OWC.
• Existing AWGR-based 2D infrared OWC systems face trade-offs between spatial resolution and channel capacity.
• Imperfect AWGR filtering causes inter-channel crosstalk, limiting system performance.

Purpose of the Study:

• To propose a filter-aided crosstalk mitigation scheme for AWGR-based 2D infrared beam-steered OWC systems.
• To eliminate the trade-off between spatial resolution and channel capacity.
• To enable denser AWGR grid configurations and reduce system complexity.

Main Methods:

• Employing digital Nyquist filters to shape the transmitted signal for narrow spectral occupancy.
• Utilizing a filter-aided crosstalk mitigation scheme.
• Leveraging mature Digital Signal Processing (DSP) techniques without additional optical components.

Main Results:

• Successfully avoided inter-channel crosstalk from imperfect AWGR filtering.
• Enabled denser AWGR grid configurations and reduced AWGR bandwidth requirements.
• Demonstrated 20-Gbit/s OWC capacity using PAM4 format over a 1.1-m free-space link.
• Showcased insensitivity to wavelength misalignment, relaxing laser design constraints.

Conclusions:

• The proposed filter-aided crosstalk mitigation scheme is feasible and effective for AWGR-based 2D infrared OWC systems.
• The method enhances channel capacity and spatial resolution without additional optical components.
• Potential for 40 Gbit/s capacity per beam by combining with polarization orthogonality.