Fiber‐Optic Sensing for Environmental Applications: Where We Have Come From and What Is Possible

The use of fiber‐optic sensors has flourished in many fields over the past 30 years. One particular branch of fiber‐optic sensing, distributed temperature sensing, has become a well‐explored and widely‐accepted tool for a diverse range of environmental applications over the past decade. Peer‐reviewed work on fiber‐optic distributed temperature sensing advanced significantly, moving from innovations in instrumentation, deployment techniques, calibration, and analysis methods to applications. However, exciting advancements in other branches of fiber optics, such as fiber Bragg gratings, optical frequency domain reflectometry, and distributed acoustic sensing, have thus far been underutilized in environmental studies and await exploitation by environmental scientists. These additional techniques offer immense possibilities for novel applications in hydrology, hydrogeology, geophysics, and other environment fields where high‐accuracy, high‐frequency, and/or high spatial resolution measurements are needed. Plain Language Summary Fiber‐optic sensor technology has improved by leaps and bounds since early applications in the 1980s and 1990s and is commonly used in many fields. To date, the use of fiber optics for environmental applications has centered around one branch of the available sensors, distributed temperature sensing. This commentary briefly discusses the development and maturation of that technology, before suggesting several other available fiber‐optic technologies that offer promise for environmental applications. Key Points Environmental applications of fiber‐optic distributed temperature sensing (FO‐DTS) have increased since 2006 Improvements in instrumentation, calibration, field methods, and analysis have slowed as FO‐DTS has matured to become a mainstream tool in environmental applications The time is ripe to test novel fiber‐optic methods that have developed in other industries