Exploit the reflected Kerr channel in a fabricated device

Determine whether the reflected Kerr channel of the integrated Si3N4/GdFeCo waveguide can be isolated, referenced, and exploited for magneto-optic readout in a fabricated device despite its large geometry-induced polarization pedestal.

Background

The reflected channel carries a Kerr rotation substantially larger than the transmitted Faraday rotation and therefore offers the stronger predicted magnetic signal. At the same time, the reflected polarization is dominated by a large, magnetization-independent pedestal caused by the dielectric discontinuity. Numerical coherent subtraction removes this pedestal, but the paper leaves unresolved whether an experimental device can perform the corresponding isolation and referencing reliably.

References

Whether the reflected channel can be exploited in a fabricated device is therefore an open experimental question rather than a settled limitation, and given the factor of six it offers over the transmitted channel, together with the quarter of the probe energy it already carries, it is a question worth answering.

— Self-consistent modelling of all-optical switching and magneto-optic readout in an integrated Si$_3$N$_4$/GdFeCo waveguide  (2608.22969 - Mulyana et al., 24 Aug 2026) in Section 4, subsection “Readout-suppression hierarchy”