Optical Comb Sources for High Dynamic-Range Single-Span Long-Haul Analog Optical Links

We present a new technique for achieving high spurious-free dynamic range in long-haul analog optical links. Our technique utilizes an optical comb as the optical carrier in an externally intensity-modulated direct-detection link architecture. By distributing the optical carrier power over the comb (in contrast to concentrating it in a single continuous-wave laser, as in a conventional link), this technique circumvents the optical power limitations imposed by stimulated Brillouin scattering allowing a substantial increase in optical launch power. Increased launch power translates directly to decreased optical amplification requirements at the link terminus and results in a significantly lower noise floor than may be achieved in a conventional link architecture. To our knowledge, the dynamic range of SFDR=105.5 dB (1-Hz bandwidth, L=50 km link) is the highest reported to date for a single-span long-haul analog optical link.