title: On-chip integrated mid-infrared GaAs/AlGaAs Mach-Zehnder interferometer.
abstract: We report the design, fabrication, and first functional verification of mid-infrared (MIR; 3-12 μm) Mach-Zehnder interferometers (MZIs). The developed MIR-MZIs are entirely chip-integrated solid-state devices based on GaAs/AlGaAs technology waveguide fabricated via conventional optical lithography and reactive ion etching (RIE). Thus, fabricated MIR-MZIs were combined with a broadly tunable quantum cascade laser (tQCL) providing a wavelength coverage of 5.78-6.35 μm. MIR-MZIs have been designed with a waveguide width of 5 μm to ensure single mode behavior, avoiding optically undefined interference patterns. Several structures with different opening angles of the Y-junction were fabricated and tested for maximizing IR radiation throughput. This study demonstrates the feasibility of the very first chip-integrated mid-infrared Mach-Zehnder structures via interference patterns produced by minute amounts of water deposited at different positions of the MIR-MZI structure.
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Ulm, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Sieger
authors.forename: Franz
authors.initials: F
authors.lastname: Balluff
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Wang
authors.forename: Seong-Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Lothar
authors.initials: L
authors.lastname: Leidner
authors.forename: Guenter
authors.initials: G
authors.lastname: Gauglitz
authors.forename: Boris
authors.initials: B
authors.lastname: Mizaikoff
mesh_terms: D000535:Aluminum / Q000737:chemistry; D001152:Arsenicals / Q000737:chemistry; D004867:Equipment Design / Q000379:methods*; D005708:Gallium / Q000737:chemistry; D007368:Interferometry / Q000379:methods; D055096:Optical Devices; D013055:Spectrophotometry, Infrared / Q000379:methods
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium; D000535:Aluminum