Tunable Microwave Photonic Filter Based on LNOI Polarization Beam Splitter and Waveguide Grating

Advances in lithium niobate photonics: development status and perspectives

“…In addition, mode-related devices, 131,244,250,251,255,261,262,267 TO-based devices, [85][86][87] Bragg grating filters, 253,256,257,264 optical true delay lines, 263 and optical phased arrays 260 have also been demonstrated in the LN platform. Most of them rely on the large refractive index contrast available in TFLN.…”

Lithium Niobate on Insulator: An Emerging Platform for Integrated Quantum Photonics

“…This enables to use the polarization degree of freedom for quantumoptical functionalities. Spatial routing of photons based on their polarization was demonstrated using a specifically designed directional coupler, [136] which can operate over a large spectral range using an adapted design. [137] Finally, waveguides in LNOI can also be designed to show no modal birefringence, [138] thus leading to degenerate propagation constants for both polarization modes.…”

“…[157] Such delays can be dynamically controlled with high speed using electro-optical switches [157] or electro-optically induced gratings, that reflect photons at different positions in the waveguide. [136] A much more compact scheme for photon storage has also been realized on the LNOI platform based on two coupled microring resonators and application of the electro-optic effect. [167] The coupled system of resonators has a dark and bright mode, where an incoming optical pulse from a coupled ridge waveguide can couple to the bright mode.…”

“…For separation of signal and idler photons of different wavelength or polarization, directional couplers made of two coupled waveguides can be used, which have already been designed and implemented on the LNOI platform, [136,214] with 10 s of micrometers in coupling length and sub-micron gap separation. Directional couplers can in principle be made to not have any inherent excess losses, if no sharp bends or strong tapers are introduced, and the total loss is determined by the propagation loss of the waveguides that constitute the coupler.…”

“…[ 157 ] Such delays can be dynamically controlled with high speed using electro‐optical switches [ 157 ] or electro‐optically induced gratings, that reflect photons at different positions in the waveguide. [ 136 ]…”