HC suppression double SB modulation w/modulators for LO Abstract
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ALMA Memo # 540
High carrier suppression double sideband modulation with integrated LiNbO3 optical modulators for photonic local oscillators
T. Kawanishi, H. Kiuchi, M. Yamada, T. Sakamoto, M. Tsuchiya, M. Izutsu, and J. Amagai
2005-09-29
We proposed high carrier suppression double sideband modulation using a Mach-Zehnder (MZ) optical modulator with active trimming technique. The modulator has a pair of trimmers in the arms of the MZ structure. The trimmers can compensate amplitude imbalance in the MZ structure due to fabrication error, where the imbalance generates residual carrier in double sideband suppressed carrier (DSB-SC) modulation. We demonstrated high carrier suppression ratio of 50dB in DSB-SC modulation at 10.5GHz, by using an integrated MZ LiNbO3 modulator, where each arm has an intensity trimmer consisting of a sub MZ interferometer. In addition, we also proposed a novel scheme for the fourth order harmonic generation with two MZ modulators. A photonic local signal of 42GHz was generated from a 10.5GHz modulating signal. The upper limit of modulating frequency in the state-of-the-art is about 50GHz, so that we can easily generate 200GHz photonic local signals by using this technique.
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