Photonics is the technology of generating, controlling, and detecting light waves and particles of light (photons). Essential on its own, the technology takes on exciting new applications when connected to the Internet of Things.
Controlling Light for Greater Efficiency
LEDs become part of the Internet of Things when connected to the internet. For the consumer, this might mean lights in a home are set to turn on and off at specific times. For a smart city, it might mean traffic lights that change to ease congestion or divert traffic around an accident or construction. Light control allows for greater efficiency and cost savings.
Connecting Light for High Speed Internet
Li-Fi, or light fidelity, is a form of wireless communication that uses light rather than radio waves. Li-Fi signals are sent by changing the brightness of light flowing through LED bulbs at high speeds. It’s faster than Wi-Fi and provides higher bandwidth. Li-Fi is ideal for use in hospitals, airplanes and other areas sensitive to electromagnetic interference. Li-Fi can also reach areas Wi-Fi can’t, such as underwater.
Detecting Light for Environment & Infrastructure
LiDAR (Light Detection and Ranging) uses lasers to measure elevation and is commonly employed by drones for environmental surveying, such as sea floor elevation. Light is projected toward the ground and how long it takes to return determines distance. Researchers recently used photonic sensors to collect temperature data and perform area mapping of a St. Louis city park.
Distributed Fiber Optic Sensing (DFOS) uses similar principles to LiDAR. The Canarsie Tunnel in New York is 95 years old and sees large amounts of traffic. Instead of closing down the Canarsie Tunnel long-term for extensive repair, fiber optic sensors were installed to monitor the tunnel walls. Light is beamed from a fiber optic cable, which bounces off the tunnel wall and back to the sensor. Discrepancies in the light frequency can indicate a fault in the wall and allow for less disruptive, targeted repairs. NASA is developing a similar system called Fiber Optic Sensing System (FOSS) to detect strain and temperature in aircraft and rocket structures.
Detecting Light for Safe Distancing & Healthcare
For autonomous vehicles, LiDAR is used at 360 degrees to detect obstacles, such as other cars, potholes, debris and pedestrians. Reflected light is converted into a 3D image that is analyzed by a computer that can send signals to slow or stop the vehicle when necessary.
In the wake of COVID-19, LiDAR is being used to monitor social distancing practices in airports. Reflected light is used to measure crowd density, and sensors can alert airport staff if an area is too heavily populated. Staff are also using the technology to identify where social distancing measures are and aren’t being maintained so they can adjust their mitigation strategies accordingly.