  Integrated polarimetric receivers have the potential to define a new
generation of lightweight, high-performance instrumentation for remote sensing.
To date, on-chip polarization-selective devices such as polarizing
beam-splitters have yet to even approach the necessary performance, due to
fundamental design limitations. Here, we propose, simulate and experimentally
demonstrate a method for realizing spatially-mapped birefringence onto
integrated photonic circuits, deemed topographically anisotropic photonics.
With this robust and widely tolerant approach, devices can be constructed with
strongly polarization-dependent modal properties and minimal wavelength
dependence. An integrated polarizing beam-splitter (PBS) is realized with
unprecedented performance: a record 0.52 octaves of fractional bandwidth (116
THz), maximum insertion loss of 1.4 +/- 0.8 dB, and a minimum extinction ratio
of 16 +/- 3 dB, pushing it into the realm of wideband spectroscopy and imaging
applications. Additionally, novel photonic structures such as
polarization-selective beam-taps and polarization-selective microring
resonators are demonstrated, enabling new on-chip polarimetric receiver
architectures.
