Techniques for fabricating Bragg reflectors on Si0(2)-Si(3)N(4)-Si0(2) rib waveguides on Si.

Bragg reflector fabrication techniques on Si0(2)-Si(3)N(4)-Si0(2) rib waveguides on Si are developed and optimized. Wafer preparation, holographic exposure, and pattern transfer techniques necessary to obtain uniform low-loss gratings have been developed. Phase drifts due to the effect of air density fluctuations during holographic exposure of the amplitude division interference type were studied and removed. These improvements enabled high quality Bragg reflectors over 5 cm (2 in.) in diameter to be reproducibly fabricated.