Dynamic indoor free-space optical communication enabled by beam steering and beam shaping.

Area of Science:

• Optical Communications
• Wireless Networking
• Signal Processing

Background:

• Indoor free-space optical communication (FSO) offers high bandwidth but faces challenges with coverage and signal strength.
• Existing FSO systems often struggle with a trade-off between the area they can cover and the power received by the device.
• Advanced beam control is needed to enhance the practicality and performance of indoor FSO links.

Purpose of the Study:

• To develop a dynamic indoor FSO system with enhanced beam control capabilities.
• To address the areal coverage versus received power trade-off in indoor FSO communication.
• To demonstrate accurate and rapid target acquisition for mobile receivers in FSO systems.

Main Methods:

• Implemented a line-of-sight optical link with advanced beam steering and shaping.
• Utilized a passive target acquisition scheme with a ring-shaped retroreflector at the receiver.
• Employed an efficient beam scanning algorithm for precise transmitter-receiver alignment.
• Tested data transmission at 1 Gbit/s using an 850 nm laser diode with 2 mW output power.

Main Results:

• Achieved millimeter-scale accuracy in locating the receiver over 3m distance.
• Demonstrated a wide field of view: ±11.25° vertical and ±18.75° horizontal.
• Completed receiver acquisition within 1.162±0.005 seconds, irrespective of receiver position.
• Successfully transmitted data at 1 Gbit/s with bit error rates below 4×10⁻⁷.

Conclusions:

• The developed dynamic indoor FSO system effectively overcomes coverage limitations.
• The passive target acquisition and advanced beam control enable robust and efficient optical links.
• This technology paves the way for high-speed, low-power indoor wireless communication.