Abstract: Devices, systems, and methods for a detection device using optical fiber are described herein. In some examples, one or more embodiments include a detection device comprising a splitter, where the splitter is to be connected to a feed leg of an optical fiber, and the splitter is to split the feed leg of the optical fiber into a destination leg and a detection leg, where the detection leg is oriented in a loop, and an actuation mechanism, where when the actuation mechanism is in an engaged orientation, the actuation mechanism is to cause a microbend in the detection leg, and when the actuation mechanism is in a disengaged orientation, the actuation mechanism is to cause the microbend to be removed from the detection leg.