Optical sensor arrangement for an optical measurement of biological parameters, in particular for an optical heart rate measurement comprises a light emitting device and a light detector. A substrate comprises a first main surface onto which the light emitting device and the light detector are mounted. A package encloses the light emitting device, the light detector and the substrate and comprises a second main surface facing the first main surface. Furthermore, the package comprises an optical light barrier designed to block light to be emitted by the light emitting device from directly reaching the light detector. A light guiding element connected to the second main surface and designed for coupling light to be emitted by the light emitting device into and/or out of a human skin tissue. Finally, a watch, in particular a wrist watch, comprises the optical sensor arrangement.
