Asymmetric dual-SSB modulation for photonic co-frequency mm-wave signals generation and DSP-free receiver

An asymmetric dual-single-sideband (SSB) modulation scheme for photonic co-frequency millimeter (mm)-wave signals generation and digital signal processing (DSP)-free receiver is experimentally demonstrated for the first time, to the best of our knowledge. To effectively avoid the sideband crosstalk in the traditional symmetric dual-SSB modulation scheme, not only two vector-modulated signals but also two unmodulated sidebands are modulated on the two asymmetric sides of an optical carrier in this scheme. An optical delay line interferometer could easily separate these two asymmetric dual-SSB signals simultaneously in the receiver, and thus the photonic frequency up-conversion is realized. Besides, this scheme is free of dispersion-induced RF power fading thanks to the SSB modulation. By this means, no digital compensation algorithms such as carrier phase recovery, fiber dispersion compensation, and channel equalization are required, contributing to the DSP-free receiver. In our experiment, two 32 GHz 3.2 Gb/s 16-ary quadrature amplitude modulation mm-wave signals are produced using two RF signals with the carrier frequencies of 12 GHz and 20 GHz. The error vector magnitude (EVM) performances of these two mm-wave signals after 25.5 km standard single-mode fiber transmission are better than 3rd Generation Partnership Project requirements without using any digital compensation algorithms.