A Segmented Photonic Digital-to-analog Converter with a High Effective Number of Bits

We demonstrate a novel photonic digital-to-analog converter (PDAC) based on a segmented architecture. The segmented PDAC is composed of compounded binary-coded and unary-coded bits, corresponding to a reduced ratio of the most significant bit to the least significant bit compared to a traditional binary PDAC. A proof-of-concept 3-bit segmented PDAC is built, which shows a greatly improved effective number of bits (ENOB) in a test frequency range of 500 MHz. A maximum ENOB of 2.94 is achieved at 400 MHz. In generating a 4-GHz linear frequency-modulated radar waveform, a gain of ~4 dB in the signal-to-noise ratio (SNR) is obtained with the novel segmented PDAC compared to that with a traditional binary PDAC.