FIELD: physics.
SUBSTANCE: in compliance with first version, this device comprises fibre with core size at some section thereof is varied along there along so that optical radiation emission is decreased in fibre section with increased core area. Decrease in radiation intensity beyond a definite level allows cancellation of optical radiation propagation. In compliance with second version, this device comprises fibre with core including an elongated cavity. The latter causes additional heat losses of optical radiation plasma. Cooling of said plasma to definite level cancels the optical radiation propagation.
EFFECT: higher reliability, lower losses.
22 cl, 11 dwg
