Isolate a single fiber, bend it slightly beyond its bend radius, measure the light that escapes. This will appear as a slight reduction in signal strength, but

Isolate a single fiber, bend it slightly beyond its bend radius, measure the light that escapes. This will appear as a slight reduction in signal strength, but won't be conclusively identifiable as a tap. https://www.thefoa.org/tech/ref/appln/tap-fiber.html https://www.thefoa.org/tech/ref/appln/tap-fiber.html