Photonic Sources for Compact CW-THz Systems

This paper presents two photonic integrated circuit based continuous wave terahertz systems. The first system integrates multiple distributed feedback lasers, optical amplifiers, and phase shifters on a single indium phosphide chip, achieving a tunable beat frequency ranging from 200 GHz to 1.2 THz. The second system employs a Y-branch DFB laser that generates dual optical modes within a single cavity, providing a stable 1 THz beat frequency with high-speed tunability and potentially low phase noise. Both systems demonstrate significant potential for scalable and high-precision CW-THz applications, such as non-destructive testing and imaging. Experimental results showcase the effectiveness of these systems in achieving accurate thickness measurements and high scan rates.