Redfern Integrated Optics (RIO) OptaSense, Inc. is an American company located in Santa Clara, California.

RIO develops and manufactures optical light sources and subsystems based on its proprietary planar external cavity laser technology (PLANEX™)
PLANEX™ laser technology provides laser sources with unique cost advantages for applications in energy technology, safety technology, infrastructure, measurement technology, and other applications.
The product spectrum includes very narrow-banded single frequency lasers at 1550 nm, as well as laser diode modules and light sources at a low cost with very low noise, unparalleled wavelength stability, compact design at low power consumption, and long lifetime.

RIO provides light sources for use in remote sensing systems, distributed fiber-optic temperature or stress sensors, the fiber-optic detection of sonic or seismic waves, high-resolution spectroscopy, or for LIDAR systems and other fiber-optic precision measurement technology.