  We produced optical waveguides in the 167Er3+ :7LiYF4 crystal with diameters
ranging from 30 to 100 mkm by using the depressed-cladding approach with
femtosecond laser. These waveguides were studied (both inside and outside) by
stationary and coherent spectroscopy on the 809 nm optical transitions between
the hyperfine sublevels of 4I15/2 and 4I9/2 multiplets of 167Er3+ ions. It was
found that the spectra of 167Er3+ were slightly broadened and shifted inside
the waveguides compared to the bulk crystal spectra. We managed to observe a
two-pulse photon echo on this transition and determined phase relaxation times
for each of waveguides. The experimental results show that the created crystal
waveguides doped by rare-earth ions can be used in optical quantum memory and
integrated quantum schemes.
