Low complexity QPSK/8QAM millimeter-wave signal generation at D-band without phase pre-coding

摘要

In this paper, we propose a D-band quadrature-phase-shift-keying (QPSK) and 8-quadrature-amplitude-modulation (8QAM) millimeter-wave (mm-wave) signal generation based on frequency quintupling by only using a phase modulator (PM). The radio frequency (RF) at 25 GHz is used to drive PM. -3rd sideband and 2nd sideband of PM output is selected to generate 125 GHz mm-wave. We apply star-QPSK constellation distribution which is suitable for frequency quintupling mm-wave generation without pre-coding. For 8QAM, the distribution of constellation can be divided into QPSK set and star-QPSK set. Two sets of constellations will be rotated after photo detector (PD) according to the positive or negative of Bessel function, respectively, so as to realize 8QAM frequency quintupling photonic mm-wave generation without phase pre-coding. Moreover, there is no redundant operation in the generation, transmitting and receiving of mm-wave. The simulation results show that the bit-error-rate (BER) of 2Gbaud QPSK and 8QAM signals are lower than 3.8 x10(-3) in 15-km and 10-km optical fiber transmission, respectively. Compared with previous mm-wave generation schemes without phase pre-coding, the complexity of the proposed scheme is the lowest.