Title :
Nonlinearity of Semiconductor Mach-Zehnder Modulator for Flat Optical Frequency Comb
Author :
Yokota, Nobuhide ; Miki, Takahiro ; Abe, Koichiro ; Yasaka, Hiroshi
Author_Institution :
Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan
Abstract :
Optical frequency combs (OFCs) generated by an InP-based semiconductor Mach-Zehnder modulator (MZM) are numerically investigated. Nonlinear phase modulation induced by drive voltages applied to the MZM prove to be useful in obtaining a flat OFC. The experimentally measured intensity deviations of OFCs reported previously are quantitatively reproduced using a numerical model considering nonlinear change of refractive index and optical absorption induced by the drive voltages applied to the MZM. It is found that such nonlinearities generate a flat nine-channel (9-ch) OFC with an intensity deviation of <;1 dB when a moderate RF drive voltage of <;5 V is used. This flat 9-ch OFC is sustained regardless of the ratio of RF drive voltages of two arms in the MZM. Conversion efficiency is reasonably high (27%), but it is decreased by optical absorption and extinction losses in the MZM.
Keywords :
III-V semiconductors; indium compounds; light absorption; optical frequency combs; optical losses; optical modulation; phase modulation; refractive index; InP; InP-based semiconductor Mach-Zehnder modulator; RF drive voltage; conversion efficiency; extinction losses; flat optical frequency comb generation; intensity deviations; nonlinear phase modulation; numerical model; optical absorption; refractive index; Fiber nonlinear optics; Optical fibers; Optical modulation; Optical refraction; Optical variables control; Mach-Zehnder modulator; nonlinear phase modulation; optical frequency comb; sideband generation;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2015.2457429
