Adaptive Profile Poling of Nanophotonic Lithium Niobate Waveguides for High Overall Nonlinear Efficiency

Case ID:

Innovators at the University of Arizona have overcome the non-uniformity issue of thin-film Lithium Niobate. Adaptive profile poling is promising to realize high nonlinear efficiency with strong material second-order nonlinearity. Nonlinear efficiency can actually increase quadratically with length using this method.

It was shown that the optical momentum mismatch caused by the thickness variation of thin-film Lithium Niobate wafers limits the overall nonlinear efficiency. In contrast to standard periodic poling where the domain inversion period is fixed, a near-ideal sinc function second-harmonic spectrum can be recovered.

Lithium Niobate is inert and difficult to etch. For decades, waveguides have used ion diffusion or proton exchange which suffer small index contrast and bulky, non-scalable, and expensive devices which require a large driving voltage. Furthermore, uncertainties in the ion implantation depth and chemical-mechanical polishing rate cause thickness variations of the device layer.

This non-uniformity has prevented the repeatable demonstration of high-performance nonlinear devices, as well as the large-scale photonic circuits based on thin-film Lithium Niobate. By implementing adaptive profile poling of nanophotonic Lithium Niobate waveguides, the innovators offer the potential for high overall nonlinear efficiency and future chip-scale integration of classical and quantum photonic systems.


  • Electro-optic modulation
  • High nonlinear efficiency
  • Tailored waveguide functionality
  • Near-ideal sinc function second-harmonic spectral recovery
  • Chip-scale integration of classical and quantum photonic systems


  • Possess higher nonlinear coefficients and is more transparent over a wide spectral window than competing AlN, GaAs, and GaP materials. 
  • Outperforms competing periodically poled waveguides which achieved ultrahigh normalized efficiency 20 times higher than state-of the-art diffused waveguides in 2018
Patent Information:
Contact For More Information:
Richard Weite
Senior Licensing Manager, College of Optical Sciences
The University of Arizona
Lead Inventor(s):
Linran Fan
Pao-Kang Chen