An optical sensor module is disclosed. The optical sensor module can include a housing comprising an air cavity. An optical emitter die can be disposed in the air cavity of the housing. A top surface of the optical emitter die can face a first side of the housing, the optical emitter die configured to emit light towards the first side of the housing. An optical sensor die can be disposed in the air cavity of the housing adjacent the optical emitter die. The optical sensor die can be spaced from the optical emitter die by a lateral distance. A top surface of the optical sensor die can face the first side of the housing. There may be no septum between the optical sensor die and the optical emitter die that optically separates the optical sensor die and the optical emitter die.