We report the first long-haul DWDM transmission using three chirp-managed lasers spaced 50-GHz apart in SSMF at 10-Gb/s. Transmission penalties less than 0.7dB over a dispersion-managed 1980-km link was measured with performance comparable to NRZ-OOK. OCIS Codes: (060.2360) Fiber optics links and subsystems; (060.4080) Modulation; (060.4510) Optical communications
IntroductionRecently, the chirp-managed laser (CML) source, was demonstrated [1, 2] as an alternate transmitter technology in a small form factor that has large dispersion tolerance and was also shown to benefit from receive-side electronic signal processing. Several single channel transmission results were reported, demonstrating the versatility of the device, including the generation of return-to-zero (RZ) alternate-mark inversion (AMI) format and it's application in a ultra-long haul transmission over 9280 km [3]. The device was primarily introduced to address the metropolitan area network applications, where reach is limited, channel spacing not very stringent, but dispersion tolerance is important. Our past measurements indicate that the CML source, with it's narrow spectral extent, could be beneficial in dense wavelength multiplexed (DWDM) networks that span large distances. We had demonstrated transmission over 1200 km of non-zero-dispersion shifted fiber (NZDSF) of a single CML source in a DWDM environment [4] without any optical dispersion compensation. In this report, we demonstrate 3-channel DWDM transmission over 24 spans (1980 km) of standard single mode fiber (SSMF), using three CML sources spaced 50-GHz apart. This is the first report of the use of the CML source in a long-haul dispersion managed DWDM transmission link at 10-Gb/s. We also compare the performance of the CML with that of the traditional chirp-free non-return-to-zero (NRZ) on-off keyed (OOK) format in the same transmission link and demonstrate comparable performance.