An ultra-broadband and fabrication-tolerant silicon polarization rotator splitter is proposed in this Letter.Benefitting from the broadband and low-loss characteristics of the bi-level taper and counter-tapered coupler,the designed device has a simulated insertion loss and crosstalk of less than 0.2 and -15 dB in the waveband from 1290 to 1610 nm. These characteristics make it valuable in applications with large bandwidth requirements, such as full-grid Coarse wavelength division multiplexer(CWDM) and diplexer/triplexer fiber-to-the-home systems.The fabrication tolerance of the design is also analyzed, showing that the device performance is quite stable with normal manufacturing errors in silicon photonics foundries.
We report a polarization dependent reflection phenomenon beyond the normal incidence with a subwavelength nanorod chain.Light waves of the transverse electric mode will be totally reflected while those of the transverse magnetic mode will transmit through.The total reflection or transmission phenomenon can be seen as a constructive or destructive interference of the incident field with the transverse mode field of the chain.With the low-loss feature and the ultra-compact characteristic,this structure may find applications in photonic circuits.
Based on a modified retrieving method, we demonstrate that hyperbolic metamaterials(HMs) have considerable robustness against disorders, even when the disorder strength is quite large. Our retrieval method is more precise when retrieving the parameters for anisotropic metamaterials. We also show that the light's negative refraction of an HM is nearly unaffected when relatively large disorders exist. These results help us to understand the HMs and they have a direct significance for experiments.
