ARROWS IN KTIOPO4

Antiresonant reflecting optical waveguides (ARROW's) have been designe d and fabricated in z-cut KTiOPO4 (KTP) by epsilon-beam direct writing and double Rb <----> K ion exchange. Strong diffusion anisotropy allo ws the realization of ARROW's in this electrooptical crystal, It was f ound, that argon-ion dry etching of the crystal surface prevents the i on exchange process totally, Using this as a new masking technique, an tiresonant reflectors with lateral tolerances of less than 0.1 mu m co uld be realized, Typical quasi-single-mode waveguiding and attenuation of about 1.0 dB/cm were observed at lambda = 860 nm, which are in goo d agreement with our simulations made by the vectorial finite element method and effective index approach.