A pressure sensor (10 for medical applications comprises a silica optical fiber extrinsic Fabry-Perot interferometric (EFPI) pressure sensor (2) and an in-fiber Bragg grating (FBG, 3). The cavity of the EFPI pressure sensor (2) is formed by the end face of the FBG (3), a glass capillary (5) and a glass diaphragm (6). The glass diaphragm (6) is secured in place by a fusion splice (7) and the glass capillary (5) by a fusion splice (8). As illustrated, incident light is directed into the FBG 3 and there are reflections in the EFPI pressure sensor (2). Applied pressure causes a deflection of the glass diaphragm (6) and hence modulation of the EFPI sensor (2) cavity. The FBG (3) is used as a reference sensor to eliminate temperature cross-sensitivity of the EFPI pressure sensor (2). The EFPI cavity was fabricated using a 200 μm silica glass fiber, a 133/220 μm (inner/outer diameter) silica glass capillary and a standard telecommunication FBG. Initially, the end faces of the 200 μm silica glass fiber and the silica glass capillary were polished and both planar surfaces were spliced together using a fusion splicer. Then the silica glass capillary was cleaved 5 mm away form the capillary/200 μm fiber splice. After that, the FBG (3) was inserted into the silica glass capillary (5) and both elements were bonded together using the fusion splicer again.