OPTICAL DEVICE COMPRISING AT LEAST ONE WAVELENGTH CONVERTER, LIGHTING MODULE AND LIGHTING DEVICE FOR VEHICLE COMPRISING SUCH AN OPTICAL DEVICE

Optical device comprising: - a wavelength conversion optical element (21), formed of a first optical medium having a first refractive index, the conversion element being configured to receive an incident light beam (1) on a first (23) of its faces and to convert the incident light beam into a converted light beam; - a reflecting optical element (22), disposed on a second (24) of the faces of the converter, the second face being opposite to the first face, the reflecting element being configured to reflect the converted light beam; - a primary optical element (3), formed of a second optical medium having a second refractive index substantially identical to the first refractive index, the primary element having a first (33) of its faces disposed in proximity to the first face of the conversion element (21), the primary element (3) being configured to receive the incident light beam (1) and transmit it to the converter (21), the primary element (3) having a second (34) of its faces forming the exit face of the primary element for the converted light beam, the exit face of the primary element being configured to minimize parasitic reflections of the converted light beam on itself.