{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T17:52:47Z","timestamp":1778694767661,"version":"3.51.4"},"reference-count":24,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2011,1,25]],"date-time":"2011-01-25T00:00:00Z","timestamp":1295913600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A theoretical study of RF-photonic channelizers using four architectures formed by active integrated filters with tunable gains is presented. The integrated filters are enabled by two- and four-port nano-photonic couplers (NPCs). Lossless and three individual manufacturing cases with high transmission, high reflection, and symmetric couplers are assumed in the work. NPCs behavior is dependent upon the phenomenon of frustrated total internal reflection. Experimentally, photonic channelizers are fabricated in one single semiconductor chip on multi-quantum well epitaxial InP wafers using conventional microelectronics processing techniques. A state space modeling approach is used to derive the transfer functions and analyze the stability of these filters. The ability of adapting using the gains is demonstrated. Our simulation results indicate that the characteristic bandpass and notch filter responses of each structure are the basis of channelizer architectures, and optical gain may be used to adjust filter parameters to obtain a desired frequency magnitude response, especially in the range of 1\u20135 GHz for the chip with a coupler separation of ~9 mm. Preliminarily, the measurement of spectral response shows enhancement of quality factor by using higher optical gains. The present compact active filters on an InP-based integrated photonic circuit hold the potential for a variety of channelizer applications. Compared to a pure RF channelizer, photonic channelizers may perform both channelization and down-conversion in an optical domain.<\/jats:p>","DOI":"10.3390\/s110201297","type":"journal-article","created":{"date-parts":[[2011,1,25]],"date-time":"2011-01-25T11:57:50Z","timestamp":1295956670000},"page":"1297-1320","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Active Integrated Filters for RF-Photonic Channelizers"],"prefix":"10.3390","volume":"11","author":[{"given":"Amr","family":"El Nagdi","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ke","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"suffix":"Jr.","given":"Tim P.","family":"LaFave","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Louis R.","family":"Hunt","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Viswanath","family":"Ramakrishna","sequence":"additional","affiliation":[{"name":"Department of Mathematical Sciences, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mieczyslaw","family":"Dabkowski","sequence":"additional","affiliation":[{"name":"Department of Mathematical Sciences, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Duncan L.","family":"MacFarlane","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marc P.","family":"Christensen","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Southern Methodist University, P.O. Box 750338, Dallas, TX 75275, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2011,1,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4628","DOI":"10.1109\/JLT.2006.885787","article-title":"Microwave photonics","volume":"24","author":"Seeds","year":"2006","journal-title":"J. Lightwave Technol"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1109\/JLT.2008.2009551","article-title":"Microwave photonics","volume":"7","author":"Yao","year":"2009","journal-title":"J. Lightwave Technol"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1996","DOI":"10.1109\/22.954820","article-title":"Characterization of a coherent optical RF channelizer based on a diffraction grating","volume":"49","author":"Wang","year":"2001","journal-title":"IEEE T. Microw. Theory"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3019","DOI":"10.1109\/JLT.2010.2072952","article-title":"Silicon RF-Photonic Filter and Down-Converter","volume":"28","author":"Tu","year":"2010","journal-title":"J. Lightwave Technol"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Pruessner, M.W., Stievater, T.H., Rabinovich, W.S., Devgan, P.S., and Urick, V.J. (2009, January 31). Silicon-on-Insulator Integrated Waveguide Filters for Photonic Channelizer Applications. Baltimore, MD, USA.","DOI":"10.1364\/CLEO.2009.JWA39"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"868","DOI":"10.1109\/TMTT.2005.863052","article-title":"A microwave channelizer and spectroscope based on an integrated optical Bragg-grating Fabry-Perot and integrated hybrid Fresnel lens system","volume":"54","author":"Winnall","year":"2006","journal-title":"IEEE T. Microw. Theory"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1109\/75.482003","article-title":"Microwave optical filters using in-fiber Bragg grating arrays","volume":"6","author":"Hunter","year":"1996","journal-title":"IEEE Microw. Guided W"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Tu, K.Y., Chen, Y.K., Leven, A., Rasras, M.S., Gill, D.M., Patel, S.S., White, A.E., Carothers, D., Pomerene, A., Grove, M.J., Sparacin, D.K., Michel, J., Beals, M., and Kimerling, L.C. (2006, January 9). Analog RF Performance of a CMOS Optical Filter. Ottawa, ON, Canada.","DOI":"10.1109\/GROUP4.2006.1708211"},{"key":"ref_9","unstructured":"Goutzoulis, A.P. (2008). Integrated Optical Channelizer, U.S. Patent 7421168B1,."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1720","DOI":"10.1109\/LPT.2006.879943","article-title":"Active integrated photonic true time delay device","volume":"18","author":"Tong","year":"2006","journal-title":"IEEE Photon. Technol. Lett"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1145","DOI":"10.1109\/LPT.2007.901435","article-title":"Slow light in a semiconductor waveguide for true-time delay applications in microwave photonics","volume":"19","author":"Ohman","year":"2007","journal-title":"IEEE Photon. Technol. Lett"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"16712","DOI":"10.1364\/OE.15.016712","article-title":"Compact 90\u00b0 trench-based splitter for silicon-on-insulator rib waveguides","volume":"15","author":"Qian","year":"2007","journal-title":"Opt. Express"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"5682","DOI":"10.1364\/AO.47.005682","article-title":"Integrated photonic coupler based on frustrated total internal reflection","volume":"47","author":"Huntoon","year":"2008","journal-title":"Appl. Opt"},{"key":"ref_14","first-page":"896","article-title":"HBr-based inductively coupled plasma etching of high aspect ratio nanoscale trenches in GaInAsP\/InP","volume":"26","author":"Zhou","year":"2008","journal-title":"J. Vac. Sci. Technol. B"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"6124","DOI":"10.1364\/AO.43.006124","article-title":"Extended lattice filters enabled by four-directional couplers","volume":"43","author":"MacFarlane","year":"2004","journal-title":"Appl. Opt"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1109\/PROC.1984.12948","article-title":"Fiber optic lattice signal processing","volume":"72","author":"Moslehi","year":"1984","journal-title":"Proc. IEEE"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1109\/50.285330","article-title":"Lightwave lattice filters for optically multiplexed communication systems","volume":"12","author":"Dowling","year":"1994","journal-title":"J. Lightwave Technol"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1364\/JOSAA.11.000236","article-title":"Z-domain techniques in the analysis of Fabry\u2013P\u00e9rot etalons and multilayer structures","volume":"11","author":"MacFarlane","year":"1994","journal-title":"J. Opt. Soc. Am. A"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1007\/s11837-009-0082-y","article-title":"Initial surface reactions of atomic layer deposition","volume":"61","author":"Kim","year":"2009","journal-title":"J. Miner. Met. Mater. Soc"},{"key":"ref_20","unstructured":"Chen, C.T. (1999). Linear System Theory and Design, Oxford University Press. [3rd ed]."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"A1","DOI":"10.1364\/JOSAA.26.0000A1","article-title":"Extended active tunable optical lattice filters enabled by four-dimensional couplers: systems modeling","volume":"26","author":"Hunt","year":"2009","journal-title":"J. Opt. Soc. Am. A"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"895","DOI":"10.1364\/JOSAA.27.000895","article-title":"Extended active optical lattice filters: filter synthesis","volume":"27","author":"Dabkowski","year":"2010","journal-title":"J. Opt. Soc. Am. A"},{"key":"ref_23","unstructured":"Tong, J. (2003). University of Texas at Dallas. Ph.D. Dissertation,."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1109\/22.618455","article-title":"Photonic signal processing of microwave signals using an active-fiber Bragg-grating-pair structure","volume":"45","author":"Hunter","year":"1997","journal-title":"IEEE T. Microw. Theory"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/11\/2\/1297\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:55:03Z","timestamp":1760219703000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/11\/2\/1297"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2011,1,25]]},"references-count":24,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2011,2]]}},"alternative-id":["s110201297"],"URL":"https:\/\/doi.org\/10.3390\/s110201297","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2011,1,25]]}}}