Traveling Wave Effects in Microwave Quantum Photonics

Traveling wave effects are increasingly exploited in microwave and terahertz quantum devices to implement novel functionalities and obtain improved performance. A suitable quantum circuit modeling approach is discussed for Josephson and bulk-material kinetic inductance traveling-wave parametric amplifiers enabling broadband, quantum-limited amplification. As another example, a multi-domain simulation approach for novel terahertz quantum cascade laser structures exploiting microwave and optical co-propagation effects is presented.