Terahertz filter and demultiplexer with photonic crystal waveguide

View Online Nano-Micro Conf., 2017, 1, 01008 | 1 Published by Nature Research Society http://nrs.org Terahertz filter and demultiplexer with photonic crystal waveguide HongJun Liu,* Zhaolu Wang, Nan Huang, Jing Han State Key Laboratory of Transient Optics and Photonics Technology, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Science, No.17 Xinxi Road,New Industrial Park, Xi'an Hi-Tech Industrial Development Zone, Xi'an, Shaanxi, China Corresponding Author. Email: [email protected] Received: 15 May 2017, Accepted: 09 June 2017, Published Online: 05 October 2017 Citation Information: HongJun Liu, Zhaolu Wang, Nan Huang, Jing Han. Nano-Micro Conference, 2017, 1, 01008 doi: 10.11605/cp.nmc2017.01008 AbstractTerahertz (THz) wave is finding growing applications in various important fields such as space science, commu-nications, and security screening [1]. Besides sources and detectors, development of THz technologies also requiresdevices to guide and manipulate THz waves. The demand for high performance quasi optic components such asfrequency filters, demultiplexer, attenuators, splitters, and polarizers is increasing [2]. We theoretically propose andinvestigate a magnetically tunable narrow-band terahertz filter and a multi-channel THz wavelength division demul-tiplexer based on photonic crystal waveguide. The optical properties of the filter have been analyzed in detail. It isfound that a single resonant peak with the central frequency of ~1 THz is existed in the transmission spectrum, whichhas a narrow full width at half maximum of <2 GHz. Moreover, under the control of an external magnetic field,transmission frequency and width of passband are adjustable, which reveals that the 2-D silicon photonic crystalwaveguide with point and line defects can serve as a continuously tunable bandpass filter at the terahertz waveband.THz division demultiplexer consists of an input waveguide that perpendicularly coupled with a series of defects cav-ities, each of which captures the resonance frequency from the input waveguide. Coupled-mode theory and finite el-ement method are used to analyze the transmission properties of the structure. It is found that the transmission wave-length centered around 1 THz can be adjusted by changing the geometrical parameters of defects cavities, whichequals to THz waves generated by optical methods such as difference frequency generation and optical rectification.Terahertz (THz) wave is finding growing applications in various important fields such as space science, commu-nications, and security screening [1]. Besides sources and detectors, development of THz technologies also requiresdevices to guide and manipulate THz waves. The demand for high performance quasi optic components such asfrequency filters, demultiplexer, attenuators, splitters, and polarizers is increasing [2]. We theoretically propose andinvestigate a magnetically tunable narrow-band terahertz filter and a multi-channel THz wavelength division demul-tiplexer based on photonic crystal waveguide. The optical properties of the filter have been analyzed in detail. It isfound that a single resonant peak with the central frequency of ~1 THz is existed in the transmission spectrum, whichhas a narrow full width at half maximum of <2 GHz. Moreover, under the control of an external magnetic field,transmission frequency and width of passband are adjustable, which reveals that the 2-D silicon photonic crystalwaveguide with point and line defects can serve as a continuously tunable bandpass filter at the terahertz waveband.THz division demultiplexer consists of an input waveguide that perpendicularly coupled with a series of defects cav-ities, each of which captures the resonance frequency from the input waveguide. Coupled-mode theory and finite el-ement method are used to analyze the transmission properties of the structure. It is found that the transmission wave-length centered around 1 THz can be adjusted by changing the geometrical parameters of defects cavities, whichequals to THz waves generated by optical methods such as difference frequency generation and optical rectification. References[1] L. Ho; M. Pepper; P. Taday, Terahertz spectroscopy: Signaturesand fingerprints. Nature Photonics. 2(9), 541 (2008). doi:10.1038/nphoton.2008.174[2] H. Bin; W. Qi Jie; Z. Ying, Broadly tunable one-way terahertzplasmonic waveguide based on nonreciprocal surface magnetoplasmons. Optics Letters. 37(11), 1895-1897 (2012). doi:10.1364/OL.37.001895