Penalty-free propagation over 600 km of non-dispersion-shifted fiber at 2.5 Gb/s using a directly laser modulated transmitter

Summary form only given. Long-haul DWDM systems require compact, low-chirp, transmitters with stabilized frequency. External modulation transmitters are expensive and require additional optics for wavelength stabilization. Directly modulated external-cavity fiber-grating lasers have frequency stability, but are limited to a penalty free propagation distance of /spl sim/117 km in non-dispersion-shifted (NDS) fiber at 2.5 Gb/s. We use a fiber-grating high-pass filter after a DFB laser transmitter and demonstrate propagation over 600 km of NDS fiber at 2.5 Gb/s with <1 GHz wavelength stability. To the best of our knowledge, this is the longest propagation distance at 2.5 Gb/s in NDS fiber using direct modulation.