Wavelength chirp in a high- kappa L quarter-wave-shifted DFB laser: characterization and influence on system performance

Time-resolved and time-averaged chirp measurements of a quarter-wave shifted 1.53- mu m DFB laser with a high-coupling coefficient are presented, showing a slow-steady shift towards shorter wavelengths lasting 1.5 ns after the laser is turned on. A simple method of screening for this phenomenon is presented. Transmission on a regular single-mode fiber reveals the effect of pattern-dependent pulse compression causing severe performance degradation in a long-haul NRZ (nonreturn-to-zero) system, but improving that of an RZ system.<
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