Improving the dynamic range of a coherent AM analog optical link using a cascaded linearized modulator

An AM coherent analog optical link is experimentally demonstrated to achieve the highest spurious-free dynamic range reported to date for a coherent system by employing a linearized cascaded electro-optic modulator. The link gives a spurious-free dynamic range of 115 dB/spl middot/Hz/sup 2/3/, with a 34-dB reduction in third-order intermodulation distortion over conventional Mach-Zehnder modulators. With the linearized modulator, our experimental results are just 3 to 6 dB away from the fundamental limit of this link; the remaining penalty is mainly due to RF components.<
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