Title :
Interferometric conversion of laser chirp to IM: effect of the interferometer free spectral range on the output nonlinear distortion
Author_Institution :
Lab. RESO, Ecole Nat. d´´Ingenieurs, Brest, France
Abstract :
The two-tone modulation behavior of a semiconductor laser followed by a Mach-Zehnder interferometer is theoretically analyzed under the small-signal assumption. Illustrations are given of the signal at the Mach-Zehnder output, showing the influence of the interferometer free spectral range on the second-order harmonic (2HD) as well as the third-order intermodulation distortion (IMD). The direct intensity modulation (IM) distortions are also reported together with those of frequency modulation (FM) to facilitate direct comparison. The results show that a Mach-Zehnder with low free spectral range is required to achieve low FM distortion levels over those of the direct IM.
Keywords :
Mach-Zehnder interferometers; chirp modulation; electro-optical modulation; frequency modulation; intermodulation distortion; optical communication equipment; optical noise; semiconductor lasers; IM; Mach-Zehnder interferometer; Mach-Zehnder output; direct IM; direct intensity modulation distortions; frequency modulation; interferometer free spectral range; interferometric conversion; laser chirp; low FM distortion levels; low free spectral range; optical communications; output nonlinear distortion; second-order harmonic; semiconductor laser; small-signal assumption; third-order intermodulation distortion; two-tone modulation behavior; Chirp; Frequency modulation; High speed optical techniques; Nonlinear optics; Optical distortion; Optical interferometry; Optical mixing; Optical modulation; Optical receivers; Optical transmitters;
Journal_Title :
Photonics Technology Letters, IEEE
