“…Besides, in the directly coupled devices, the propagating modes can be made to be drastically different, so that a high birefringence, and thus, a further reduced device length are obtained. There are recent advances in hybrid plasmon‐based polarization rotators , however, the device that offers an ultrashort device length at a reasonably low insertion loss is still out of reach. The best device so far achieved rotation at a device length of 3.2 μm and an insertion loss of ∼1.38 dB .…”