Thin film lithium niobate photonic digital-to-analog converter with frequency-interleaving structure

Integrated photonic digital-to-analog converters (PDACs) offer improved stability with a more compact size compared to conventional discrete-device-based PDACs. However, the nonlinearity of modulators and the square-law detection characteristics of photodetectors limit the spurious level of coherent integrated PDACs. Here, we propose and demonstrate a novel, to the best of our knowledge, thin film lithium niobate (TFLN) PDAC with frequency-interleaving structure (TFLN-FI-PDAC). By using the TFLN platform, which has better electro-optical modulation linearity, single-tone and four-tone signal generation with spurious-free dynamic range (SFDR) >47 dB were generated in the experiment. Furthermore, a linear frequency-modulated (LFM) signal with a bandwidth of 4 GHz was generated, and the calculated signal to clutter ratio (SCR) is more than 50 dB.