CMW-UWB and MMW-UWB signal generator based on single-sideband optical up-conversion technique

A novel centimeter-wave (CMW) and millimeter-wave (MMW) ultra-wideband (UWB) signal generator based on optical up-conversion technique is presented. A dual-parallel Mach–Zehnder modulator is employed to modulate the electrical baseband UWB signal to an optical carrier and eliminate the local oscillator component. Meanwhile, a Mach–Zehnder modulator and an optical bandpass filter produce a carrier-suppressed single sideband (CS-SSB) signal. Then, the UWB modulated optical signal is combined with the CS-SSB signal for photonic frequency up-conversion. Subsequently, the combined optical signal is injected into a balanced photodetector that is used for both heterodyne detection and low-frequency components suppression. A theoretical simulation and a proof-of-concept experiment are carried out to verify the feasibility of the proposed scheme. Eventually, a CMW-UWB signal is generated having a spectral power efficiency (SPE) of 54.25% and a 10-dB bandwidth of 5.89 GHz. An MMW-UWB signal is generated having an SPE of 54.12% and a 10-dB bandwidth of 5.67 GHz. Compared with other methods, the proposed generator can generate high-order CMW-UWB signal in a simpler structure since the up-conversion technique is employed. And the SSB up-conversion technique used in this generator overcomes the instability problem existing in the uncorrelated heterodyne method. The generated UWB signals both fulfil the requirements specified by the Federal Communications Commission.