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Injection locking of mid‐infrared quantum cascade laser at 14 GHz, by direct microwave modulation
Author(s) -
StJean Margaux Renaudat,
Amanti Maria Ines,
Bernard Alice,
Calvar Ariane,
Bismuto Alfredo,
Gini Emilio,
Beck Mattias,
Faist Jerome,
Liu H. C.,
Sirtori Carlo
Publication year - 2014
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.201300189
Subject(s) - quantum cascade laser , laser , optoelectronics , semiconductor laser theory , microwave , cascade , injection locking , frequency modulation , materials science , modulation (music) , optics , quantum dot laser , semiconductor , physics , radio frequency , telecommunications , computer science , chemistry , chromatography , quantum mechanics , acoustics
Compact laser sources operating in mid infrared spectral region with stable emission are important for applications in spectroscopy and wireless communication. Quantum cascade lasers (QCL) are unique semiconductor sources covering mid infrared frequency range. Based on intersubband transitions, the carrier lifetime of these sources is in the ps range. For this reason their frequency response to direct modulation is expected to overcome the limits of standard semiconductor lasers. In this work injection locking of the roundtrip frequency of a QCL emitting at 9 μm is reported. Inter modes laser frequency separation is stabilized and controlled by an external microwave source. Designing an optical waveguide embedded in a microstrip line a flat frequency response to direct modulation up to 14 GHz is presented. Injection locking over MHz frequency range at 13.7 GHz is demonstrated. Numerical solutions of injection locking theory are discussed and presented as tool to describe experimental results.