Patent ID: 8655117

Claim:
An optical fiber sensor, comprising: a lead-in optical fiber having an end surface at a forward end; a first optical element having a body with an outer dimension, Do, a front end surface coupled to the lead-in optical fiber, a pedestal including a retracted surface that is spaced from the front end surface, the retracted surface at least partially defining an optical cavity, a gutter surrounding the pedestal, the gutter having a gutter depth defining an active region of length, L, wherein L is defined by a forward end of the lead-in optical fiber and a bottom of the gutter, the first optical element further exhibiting L/Do≧0.5 wherein the gutter includes an inner gutter wall and an outer gutter wall, such that the inner gutter wall and the outer gutter wall are tapered relative to an optical element longitudinal axis so as to define a generally conical-shape to the pedestal.