Generation and optimization of optical single-sideband signal using multi-harmonic phase modulation

• Proposed a novel phase modulation method for optical single-sideband signal generation. • Proposed an intelligence optimization algorithm based on the Mountain Gazelle Optimizer for our modulation system. • OSSB signal with approximately 80% energy efficiency was achieved experimentally. Optical single sideband (OSSB) signals are widely used in optical communication systems owing to their effective anti-dispersion capability and high spectral efficiency. To address the challenge of high efficiency generation of OSSB signals, we propose a method based on multi-harmonic phase modulation (MHPM) with the mountain gazelle optimizer (MGO). By constructing a multi-objective optimization model, synergistic optimization of modulation depth, phase, and harmonic order was achieved, followed by simulation and experimental investigation. Simulation results indicate that at the 10th harmonic order, the energy efficiency (EF) of the OSSB signal, defined as the ratio of target sideband optical power to total output optical power, including the carrier, reached 88.04 %. This corresponds to an improvement of more than 38 % over the traditional optical double sideband (ODSB) scheme and yielding a high carrier suppression ratio (CSR) of 23.69 dB and sideband suppression ratio (SSR) of 18.53 dB. In the experimental stage, a narrow-linewidth fiber laser and an electro-optic phase modulator were employed to perform 10th-harmonic phase modulation, yielding an OSSB signal with an EF of approximately 80 %. The experimental results showed good agreement with the simulations, confirming that the intelligent algorithm can effectively address the multi-objective optimization challenges introduced by MHPM. This work provides a novel approach for complex multi-parameter coupling optimization in phase modulation systems and offers new insights for efficiently handling related problems in the fields of optical fiber communications and microwave photonics.