Open AccessModulation-format-free and automatic bias control for optical IQ modulators based on dither-correlation detection
Author(s) -
Xiaolei Li,
Lei Deng,
Xiaoman Chen,
Mengfan Cheng,
Songnian Fu,
Ming Tang,
Deming Liu
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.009333
Subject(s) - dither , phase shift keying , computer science , modulation (music) , signal (programming language) , demodulation , optics , phase modulation , transmission (telecommunications) , electronic engineering , physics , telecommunications , bit error rate , phase noise , engineering , bandwidth (computing) , channel (broadcasting) , acoustics , programming language
A novel automatic bias control (ABC) method for optical in-phase and quadrature (IQ) modulator is proposed and experimentally demonstrated. In the proposed method, two different low frequency sine wave dither signals are generated and added on to the I/Q bias signal respectively. Instead of power monitoring of the harmonics of the dither signal, dither-correlation detection is proposed and used to adjust the bias voltages of the optical IQ modulator. By this way, not only frequency spectral analysis isn't required but also the directional bias adjustment could be realized, resulting in the decrease of algorithm complexity and the growth of convergence rate of ABC algorithm. The results show that the sensitivity of the proposed ABC method outperforms that of the traditional dither frequency monitoring method. Moreover, the proposed ABC method is proved to be modulation-format-free, and the transmission penalty caused by this method for both 10 Gb/s optical QPSK and 17.9 Gb/s optical 16QAM-OFDM signal transmission are negligible in our experiment.