A Fiber-optic mm-wave Radio Using Overdriven Mach-Zehnder Interferometric Modulator

In this paper, a new scheme for fiber-optic mm-wave radio has been theoretically proposed using a overdriven Mach-Zehnder interferometric modulator. Using a fundamental microwave modulating signal and providing a proper dc bias to the overdriven Mach-Zehnder interferometric modulator placed at the central station, mm-wave intensity modulation of the optical carrier can be generated at the harmonic frequencies of the fundamental microwave drive. Each mm-wave will carry the same baseband frequency modulation present in the microwave modulating signal. The desired mm-wave at the output of the photodiode (PD) in the base station can be filtered and amplified by an injection-locked tunable mm-wave Gunn oscillator and then radiated over a cell. Different mm-wave frequencies are used in each base station, thereby reducing the scope of interference between adjacent cells. Typical value of calculated CNR at the output of the PD is 32 dB for modulator input optical power of 1 mW.