Building tiny, high-quality lasers in the green and yellow wavelength ranges of the visible spectrum has been a long-standing challenge. But researchers have discovered that by tweaking existing optical technology, they can fill the so-called “green gap” to benefit applications including quantum computing and underwater communications.
An optical fiber-based measurement system that uses fiber Bragg grating sensors is now helping engineers to keep railways on track. The new system can continuously monitor a railway’s catenary structure and pantograph—the components that, when combined, power trains.
An evolving national security risk to communications and navigation has motivated scientists to develop a chipscale photonic modulator that can control light on a silicon photonic microchip. This ultraprecise quantum inertial measurement unit could be an alternative to GPS when satellites are hampered in some way, and potentially be used in LiDAR and quantum computing.
