Chirp Multiplication by Four Wave Mixing for Wideband Swept-Frequency Sources for High Resolution Imaging

• Published in: Journal of lightwave technology Vol. 28; no. 14; pp. 2077 - 2083
• Main Authors: Satyan, Naresh, Rakuljic, George, Yariv, Amnon
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.07.2010; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bandwidth; Chirp; Dispersions; Fiber nonlinear optics; Four-wave mixing; Frequency; Frequency conversion; High speed; High speed optical techniques; High-resolution imaging; Imaging; laser radar; Nonlinear optics; Nonlinearity; optical imaging; Optical mixing; Wideband
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2010.2051659

We present an analysis and demonstration of the doubling of the chirp rate and total chirp bandwidth of a frequency chirped optical signal by the process of four-wave mixing in a non-linear optical medium. The effects of chromatic dispersion and input power on the maximum achievable output bandwidth are analyzed, and a dispersion compensation technique for phase matching is described. The doubling of an input linear frequency sweep of 100 GHz/1 ms in a highly nonlinear optical fiber is experimentally demonstrated. Further, it is proposed that a cascaded implementation of the four-wave mixing process leads to a geometric increase in the bandwidth of the frequency chirp. With an electronically tuned chirped laser at the input stage, this process can be used to generate extremely wideband swept frequency sources with no moving parts, for applications in high-speed and high-resolution optical imaging and spectroscopy.