Patent ID: 7710552

Claim:
Apparatus for extracting light from an optical waveguide ( 12 ) by bending the waveguide to such an extent that a portion of any light propagating in the waveguide leaks therefrom, comprising: (i) a bending unit ( 10 ) for bending a portion of the waveguide in dependence upon a control signal (S) and providing a detection signal (P d ) proportional to light leaked from the waveguide; (ii) and a control unit ( 14 ) for varying the control signal (S) in response to said detection signal (P d ) to cause the bending unit ( 10 ) to progressively decrease the bending radius (R), the control unit computing a rate of change of said detection signal (P d ) with respect to bending radius (R) and causes the bending unit to maintain that bending radius at which the aforesaid rate of change is substantially equal to a predetermined value.