Patent ID: 8253945

Claim:
A method of fabricating an optical sensor comprising the steps of: providing a body; forming an enclosed cavity in the body such that the cavity is closed at a first end by a membrane and at a second end by a wall, wherein said wall and said membrane are included in said body, the cavity being defined by an inner surface of the membrane forming a first surface reflective to incident light and an inner surface of the wall forming a second surface reflective to incident light, the first and second surfaces defining a Fabry-Perot cavity; and securing an optical fibre to the body at an outer surface of the wall, said optical fibre being spaced from said enclosed cavity, and arranging said optical fibre to optically couple incident light output from the optical fibre, through the wall, to the Fabry-Perot cavity and to receive reflections from the first and second surfaces of the cavity, wherein said optical fibre does not contact the inner surface of the wall, and wherein the core of the optical fibre is formed of sapphire, and wherein the body is made entirely of sapphire.