No abstract

A waveguide optical isolator based on nonreciprocal interference is demonstrated. Ridge waveguides are fabricated in a Mach–Zehnder configuration on a single film of bismuth-, lutetium-, neodymium-iron garnet. With this design, no polarizers are required to achieve extinction in the backward propagation direction. This isolator exhibits a 19 dB extinction ratio at λ=1.54 μm. A flat wavelength dependence, to within 2 dB, has been observed in the range between 1.49 and 1.57 μm.

We demonstrate the integration of a single-crystal magneto-optical film onto thin silicon-on-insulator (SOI) waveguides by use of direct wafer bonding. Simulations show that the high confinement and asymmetric structure of SOI allows an enhancement of approximately 3x over the nonreciprocal phase shift achieved in previous designs; this value is confirmed by our measurements. Our structure will allow compact magneto-optical nonreciprocal devices, such as isolators, integrated on a silicon waveguiding platform.

An observation of self-focusing of dipolar spin waves in garnet film media is reported. In particular, we show that the quasistationary diffraction of a finite-aperture spin-wave beam in a focusing medium leads to the concentration of the wave power in one focal point rather than along a certain line ͑channel͒. The obtained results demonstrate the wide applicability of nonlinear spin-wave media to study nonlinear wave phenomena using an advanced combined microwave-Brillouin-light-scattering technique for a two-dimensional mapping of the spin-wave amplitudes.

No abstract

No abstract

Garnet films of composition Lu3−xBixFe5−yGayO12 are grown by liquid-phase epitaxy on [111]-oriented substrates of gadolinium gallium garnet. Faraday rotation and saturation magnetization are measured as a function of substitution levels, which range up to x=1.4 and y=1.8, respectively. Nonreciprocal propagation of the TM0 is studied at a wavelength of 1.3 μm. It is shown that the difference between forward and backward propagation constants can be optimized using double layers with opposite sign of the Faraday rotation. Agreement between experiments and calculations is excellent.

We report on measurements of the twodimensional intensity distribution of linear and non-linear spin wave excitations in a LuBiFeO film. The spin wave intensity was detected with a high-resolution Brillouin light scattering spectroscopy setup. The observed snake-like structure of the spin wave intensity distribution is understood as a mode beating between modes with different lateral spin wave intensity distri-butions. The theoretical treatment of the linear regime is performed analytically, whereas the propagation of non-linear spin waves is simulated by a numerical solution of a non-linear Schrödinger equation with suitable boundary conditions. Index Terms-Brillouin light scattering spectroscopy, micro-waves, non-linear spin-wave excitation