Аннотация:The measurement results of output optical power (Pt) of double-heterojunction laser (DHL) based on the Ga- As and fiber optic Bragg grating are presented before and after the influence of protons (p+) with an energy of 21 MeV and fluence level of 5·10^14 p+/cm 2 . The Pt degradation at 850 nm wavelength is no more than 15%. The Pt degradation occurs due to the secondary particles produced by proton braking in a heterolaser enclosure and determined by the Ga-As radiation hardness.