Fig. 1. (a) Schematic of the proposed silicon integrated magneto-optical phased array. (b) Sketch of the phase element array in the device. (c) Cross sectional structure of Si waveguides. (d) Cross sectional structure of MO/Si waveguides. (e) Simulated transmission power of a proposed optical circulator. (f) Simulated transmission power of the proposed magneto-optical phased array.

Fig. 2. (a) Simplified schematic diagram of the proposed device. (b) Forward and backward theoretical transmission phase gradients of the proposed optical circulator using the focusing structure. (c) Forward transmission focusing efficiency changing with the number of the arrayed waveguides when the length of the output slab Si waveguide f2 takes different values.

Fig. 3. (a) Isolation ratio and (c) insertion loss of the designed magneto-optical phased array under different distances D between the backward output ports and different numbers of arrayed waveguides when the length of the input slab Si waveguide f1=200μm. (b) Isolation ratio and (d) insertion loss of the designed magneto-optical phased array under different lengths of the input slab Si waveguide f1 and numbers of arrayed waveguides when the distance between the backward output ports D=6μm.

Fig. 4. (a) Illustration of three-port optical circulation function based on the nonreciprocal optical focusing. (b) Theoretical transmission spectra of the three-port optical circulator. (c) Illustration of four-port nonreciprocal optical transmission. (d) Theoretical transmission spectra of the four-port nonreciprocal optical device. (e) The corresponding forward and backward theoretical transmission phase gradients of the proposed four-port device.

Fig. 5. (a) Illustration of nonreciprocal optical transmission in a 5×5 silicon integrated magneto-optical phased array. (b) Forward and backward theoretical transmission phase gradients of the proposed 5×5 magneto-optical phased array. (c) Theoretical transmission spectra of the magneto-optical phased array when the forward light was incident from I₃. (d) Theoretical transmission spectra of the magneto-optical phased array when the backward light was incident from O₃.

Fig. 6. (a) Optical microscope image of the fabricated three-port optical circulator. The inset is the scanning electron microscope (SEM) image of the cross-sectional structure of the MO/Si waveguide. (b) Experimentally measured transmission spectra of the three-port optical circulator. (c) Optical microscope image of the fabricated four-port nonreciprocal optical device. (d) Experimentally measured transmission spectra of the four-port nonreciprocal optical device.

Fig. 7. (a) Optical microscope image of the fabricated 5×5 magneto-optical phased array. (b) Experimentally measured transmission spectra of the 5×5 magneto-optical phased array when the forward light was incident from I₃. (c) Experimentally measured transmission spectra of the 5×5 magneto-optical phased array when the backward light was incident from O₃.