In the course of producing waveguides for laser applications, liquid p
hase epitaxy has been used to grow thin films of LiY(1-x-y)Ln(x)Gd(y)F
(4)(Ln = Nd or Er) on LiYF4 substrates. Covered by a LiYF4 cladding la
yer, waveguides of low optical loss( < 0.3 dB/cm) were obtained. The g
rowth rates appear to be determined by surface kinetics rather than by
diffusion in the liquid phase.