Wuhan Research Institute of Posts and Telecommunications

Cai Li

Shaohua Yu

Qi Yang

Zhu Yang

A transmitting system, a receiving system, a transmitting method and a receiving method capable of implementing communications with multiple rates are described. The transmitting system comprises: a transmitting-side selection apparatus for selectively inputting input bit data to one of a first constellation mapping modulation apparatus and a second constellation mapping modulation apparatus based on a rate to be transmitted; the first constellation mapping modulation apparatus for performing a first constellation mapping modulation on the signal input thereto based on a selection made by the transmitting-side selection apparatus, so as to obtain a constellation-mapped signal; the second constellation mapping modulation apparatus for performing a second constellation mapping modulation on the signal input thereto based on the selection made by the transmitting-side selection apparatus, so as to obtain a constellation-mapped signal; and an OFDM modulation apparatus for performing an OFDM modulation on the constellation-mapped signal to obtain an OFDM-modulated signal for transmission.

Transmitting system and receiving system, and transmitting method and receiving method

A bias voltage control system and method for an optical IQ modulator are disclosed. The optical IQ modulator includes an I-branch Mach-Zehnder Modulator (MZM) to which an I-branch bias voltage is applied, a Q-branch MZM to which a Q-branch bias voltage is applied, and an optical phase shifter to which an orthogonal bias voltage is applied. The system comprises a photo-detector converting at least a part of an optical signal output by the optical IQ modulator to an electrical signal; an analog-to-digital converter converting the electrical signal to a digital signal; and a digital signal processor superimposing a first dither signal and a second dither signal on the I-branch bias voltage and the Q-branch bias voltage respectively to generate a first order harmonic signal and a second order harmonic signal, and controlling the bias voltages according to powers of a DC component, and the first and second order harmonic signals.

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Wuhan, China

Cai Li