  Integrated optics has distinct advantages for applications in space because
it integrates many elements onto a monolithic, robust chip. As the development
of different building blocks for integrated optics advances, it is of interest
to answer the important question of their resistance with respect to ionizing
radiation. Here we investigate effects of proton radiation on high-Q silicon
nitride microresonators formed by a waveguide ring. We show that the
irradiation with high-energy protons has no lasting effect on the linear
optical losses of the microresonators.
