On-chip nonlinear optical physical unclonable function based on a thin-film lithium niobate array

We propose and simulate an optical physical unclonable function (PUF) scheme that exploits nonlinear modulation in an integrated thin-film lithium niobate (TFLN) scattering array. The device consists of a silica grating structure, which randomly scatters components of different wavelengths, and a random lithium niobate array, which induces mutual temporal modulation among the input signals. First, simulations examine the wavelength-dependent scattering and the resulting nonlinear effects, confirming the theoretical basis for temporal encryption via mutual modulation in the lithium niobate pattern. Next, simulations verify the PUF's unpredictability, reproducibility, and unclonability. By varying the challenge wavelength and its coding format, we further demonstrate a strategy for expanding the challenge-response pair (CRP) space, which is calculated to be approximately one million. Subsequently, an identity authentication scheme is proposed, and its security under link attacks is analyzed. This work lays the foundation for the design and implementation of TFLN PUF and provides a new security authentication solution for IoT devices.