Wireless optical power transfer system by spatial wavelength division and distributed laser cavity resonance

Area of Science:

• Optoelectronics
• Wireless Power Transfer
• Laser Physics

Background:

• Wireless optical power transfer (WOPT) systems are crucial for powering devices without physical connections.
• Existing WOPT systems face challenges in efficiency, alignment, and safety over wide areas.
• Laser cavity resonance offers potential for enhanced power transfer but requires robust implementation.

Purpose of the Study:

• To propose and demonstrate a novel wireless optical power transfer (WOPT) system.
• To utilize diverging angular dispersion and spatially distributed laser cavity resonance for efficient power delivery.
• To ensure system safety through an automatic mechanism that halts operation when the line of sight is broken.

Main Methods:

• A transmitter uses a diffraction grating to spatially disperse broadband light from a semiconductor optical amplifier.
• Receiving units with retroreflecting beam splitters establish multiple resonant cavities by reflecting light back to the transmitter.
• An automatic safety mechanism is implemented to cease cavity resonance if the transmitter-receiver line of sight is interrupted.

Main Results:

• A single-channel WOPT system achieved a resonating average power of 17.2 mW, with 1.7 mW delivered to photodetectors over 1 meter.
• The system operated with a narrow channel linewidth of 0.035 nm.
• A proof-of-principle experiment successfully powered seven receiver units simultaneously.

Conclusions:

• The proposed WOPT system demonstrates a viable method for safe and efficient wireless power delivery.
• Retroreflectors facilitate user-friendly alignment and power tapping from the resonant cavity.
• Further optimization of retroreflector design and field-of-view can pave the way for commercial applications.