Optical millimeter-wave generation with subcarrier variable based on optical phase locking

A novel scheme for the generation of photonic millimeter-wave was proposed, which is applicable to optical/wireless hybrid access network. Based on the characteristic that a wide spectrum signal can be produced by modulating a distributive feedback semiconductor laser, a laser is directly modulated with low-frequency sinusoidal signal. The laser' s spectrum is broadened and then injected into a series of phase-locked semiconductor lasers to make themselves coherent light sources. The light sources are used to load different signals at different wavelengths for transmission. At the receiving end, optical filters with different passband characteristics are used for signal processing, selectively receiving the baseband signal, optical microwave clock signal, and the uplink light sources or up conversion signals modulated with different subcarrier frequency. As verification, the generation and reception of subcarrier-modulated optical signal for 2.5 Gbps baseband signal, 20 GHz and 40 GHz are completed. Due to the limited experimental conditions, only the theoretical verification was conducted. Though, as the system can be integrated with waveguide design, an optical microwave signal with higher carrying frequency can be generated. It is very beneficial to future optical/wireless hybrid access and the system of ultra-dense wavelength division multiplexing.