Title :
Coupled-Mode Theory for Cherenkov-Type Guided-Wave Terahertz Generation Via Cascaded Difference Frequency Generation
Author :
Pengxiang Liu ; Degang Xu ; Hong Yu ; Hao Zhang ; Zhongxiao Li ; Kai Zhong ; Yuye Wang ; Jianquan Yao
Author_Institution :
Inst. of Laser & Optoelectron., Tianjin Univ., Tianjin, China
Abstract :
A scheme for monochromatic terahertz (THz) generation via cascading enhanced Cherenkov-type difference frequency generation (DFG) in a sandwich-like waveguide is proposed. The novel scheme has the potential to overcome the quantum-defect limit and to provide an efficient output coupling. This process is elucidated by developing a coupled-mode theory and taking into account the pump depletion, waveguide mode properties, and THz output coupling. The effect of cascading enhancement is analyzed by comparing with non-cascaded DFG situation. It is predicted that THz power can be boosted by nearly 8-fold with a 400 MW/cm2 pump in a 40-mm-long Si-LiNbO3-Si waveguide.
Keywords :
coupled mode analysis; elemental semiconductors; lithium compounds; microwave photonics; optical couplers; optical frequency conversion; optical pumping; optical waveguides; quantum optics; silicon; terahertz wave generation; Cherenkov-type guided-wave terahertz generation; Si-LiNbO3-Si; THz output coupling; cascaded difference frequency generation; coupled-mode theory; monochromatic terahertz generation; pump depletion; quantum-defect limit; sandwich-like waveguide; size 40 mm; waveguide mode properties; Absorption; Couplings; Laser excitation; Mathematical model; Optical frequency conversion; Optical waveguides; Cascaded frequency down-conversion; Cherenkov phase-matching; difference frequency generation; optical waveguide; terahertz generation;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2013.2268876
