Garnet films of composition (Gd, Bi)3(Fe, Ga)5O12 are grown by liquid-phase epitaxy on (111) oriented substrates of gadolinium gallium garnet. The films are close to compensation. Using laser annealing straight vertical compensation walls (CW) are generated. Monomode rib waveguides are fabricated by ion beam etching so that a CW is located close to a rib center. The CW induces a nonreciprocal phase shift of the TE0 mode. The dependence of this phase shift on the position of the CW within the rib is calculated. Experimentally a phase shift of 0.7 cm-1 at 1.3 μm wavelength is observed. The deviation from the theoretical value is discussed. Such waveguides are essential to realize polarization-independent optical isolators.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)