Towards power-efficient long-reach underwater wireless optical communication using a multi-pixel photon counter

Area of Science:

• Optical Engineering
• Wireless Communication
• Photonics

Background:

• Underwater wireless optical communication (UWOC) systems face significant distance limitations due to light intensity decay in water.
• Developing long-reach UWOC is crucial for various underwater applications.

Purpose of the Study:

• To propose and experimentally demonstrate a long-reach UWOC system.
• To investigate the use of power-efficient pulse position modulation (PPM) and ultra-sensitive multi-pixel photon counters (MPPC) for enhanced UWOC performance.

Main Methods:

• Implementation of a 46-meter UWOC system.
• Utilizing pulse position modulation (PPM) for data encoding.
• Employing multi-pixel photon counters (MPPC) for signal detection.
• Operating the laser under stimulated and spontaneous states.

Main Results:

• Successful experimental demonstration of a 46-meter UWOC link.
• Obtained clear eye diagrams for ten different PPM signals at Mbps data rates.
• Achieved ultra-low received optical power levels as low as -39.2 dBm (10-MHz 4-PPM, stimulated state) and -62.8 dBm (5-MHz 64-PPM, spontaneous state).

Conclusions:

• The proposed PPM and MPPC-based UWOC system effectively overcomes distance limitations.
• Ultra-low transmitting power is feasible for long-reach underwater optical communication.
• This technology paves the way for advanced underwater networking and sensing.