Optical sensor

An optical sensor for determining at least one of a physical parameter and a chemical parameter of a gas sample, comprising:

• at least one optical transmitter;
• at least one optical receiver;
• an evaluation unit arranged downstream of the receiver;
• and
• a gas-sensitive element which is arranged in a beam path between the transmitter and the receiver and is exposable to the gas sample, and which changes at least one of a absorption index and a refractive index for electromagnetic radiation of a specific wavelength in a reversible manner in response to a change in parameters of the gas sample, the gas-sensitive element including an indicator substance in a polymer matrix, the transmitter and the receiver being coupled to the gas-sensitive element via at least one optical waveguide, wherein:
• the optical transmitter, the optical receiver, and the gas-sensitive element are matched to a wavelength range,
• the receiver includes a photodiode,
• the gas-sensitive element includes a gas-sensitive layer that changes at least one of the absorption index and the refractive index for electromagnetic radiation in response to contact with a gas or gas mixture,
• the at least one optical waveguide, at an end thereof facing away from the receiver and the transmitter, is chamfered and provided with the gas-sensitive layer, and
• the end of the at least one optical waveguide facing away from the receiver and the transmitter includes a peak having a peak angle of 90°.