A Broadband Linearized Coherent Analog Fiber-Optic Link Employing Dual Parallel Mach-Zehnder Modulators

A composite optical transmitter based on dual parallel Mach-Zehnder modulators is proposed to linearize double-sideband suppressed-carrier coherent analog fiber-optic links. The optimization condition for achieving the best spurious-free dynamic range (SFDR) is discussed, with a simple and exact expression for the maximized SFDR being derived. Unlike other existing linearization schemes, the proposed technique has the advantages of broadband operation and shot-noise-limited signal-to-noise ratio at the same time. For a lossless link employing a transmitter laser with moderate optical power of 100 mW, a broadband SFDR as high as 144 dB . Hz(4/5) is theoretically predicted.