Optical spectra and the system performance of 1.55micron DFB lasers.

Static and dynamic optical spectra of 1.55micron DCPBH-DFB lasers are analyzed. These lasers were packaged in hermetic TECPACs and directly modulated with 1206A and 1210A transmitter circuitry. We have found that their static spectra observed under cw operation have fine structure induced by optical feedback from the far end of the package fiber pigtail. The dynamic spectra taken under pulsed modulation differ significantly from the static spectra in two ways. The dynamic spectra are narrower than the structured static spectra when a fixed data pattern is applied to the lasers and broader when a random data pattern is used.