An optical sensing apparatus for measuring changes in pressure or force, the optical sensing apparatus comprising: first and second optical fibre portions (200, 202, 602, 604) with Bragg gratings, a sensing region for exposing both the first and second optical fibre portions (200, 202, 602, 604) with the Bragg gratings to changes in the pressure or force and in temperature; and a holder for holding the first and second optical fibre portions (200, 202, 602, 604) in the sensing region; wherein, within the sensing region, the first and second optical fibre portions (200, 202, 602, 604) are arranged relative to each other such that the change in the force or pressure results in an increase in the optical property of one of the first and second optical fibre portions (200, 202, 602, 604) and a decrease in the optical property in the other one of the first and second optical fibre portions (200, 202, 602, 604); and wherein the apparatus is also arranged for measuring a change in temperature in a manner such that the change in temperature causes either an increase of the optical property of both optical fibre portions (200, 202, 602, 604) or a decrease of the optical property of both optical fibre portions(200, 202, 602, 604). first and second optical fibre portions (200, 202, 602, 604) with Bragg gratings, a sensing region for exposing both the first and second optical fibre portions (200, 202, 602, 604) with the Bragg gratings to changes in the pressure or force and in temperature; and a holder for holding the first and second optical fibre portions (200, 202, 602, 604) in the sensing region; wherein, within the sensing region, the first and second optical fibre portions (200, 202, 602, 604) are arranged relative to each other such that the change in the force or pressure results in an increase in the optical property of one of the first and second optical fibre portions (200, 202, 602, 604) and a decrease in the optical property in the other one of the first and second optical fibre portions (200, 202, 602, 604); and wherein the apparatus is also arranged for measuring a change in temperature in a manner such that the change in temperature causes either an increase of the optical property of both optical fibre portions (200, 202, 602, 604) or a decrease of the optical property of both optical fibre portions(200, 202, 602, 604). a sensing region for exposing both the first and second optical fibre portions (200, 202, 602, 604) with the Bragg gratings to changes in the pressure or force and in temperature; and a holder for holding the first and second optical fibre portions (200, 202, 602, 604) in the sensing region; wherein, within the sensing region, the first and second optical fibre portions (200, 202, 602, 604) are arranged relative to each other such that the change in the force or pressure results in an increase in the optical property of one of the first and second optical fibre portions (200, 202, 602, 604) and a decrease in the optical property in the other one of the first and second optical fibre portions (200, 202, 602, 604); and wherein the apparatus is also arranged for measuring a change in temperature in a manner such that the change in temperature causes either an increase of the optical property of both optical fibre portions (200, 202, 602, 604) or a decrease of the optical property of both optical fibre portions(200, 202, 602, 604).