Dispersion penalty and performance of directly modulated 14pin butterfly packaged External Cavity Laser Diode with 2.5 Gb/s speed and transmission distance of 650km

摘要

Directly modulated External Cavity Laser Diode (ECLD) is an attractive alternative for extended reach source lasers for metro area telecommunications. This paper reports ECLD with transmission rate of 2.5Gbit/s and transmission distance of 650 km packaged in industry standard 14pin butterfly package. High stability package was the key in achieving Telcordia qualification. Combination of narrow linewidth and high bandwidth allows OC-48 transmission for distances comparable with the ones typical for EML. This lasers exhibit +/-30 pm wavelength stability over temperature range of -15 to +75C which makes it suitable for 100 and 50 GHz spacing applications without wavelength locker. ECLD can be operated using standard laser driver. Results using Vitesse 7940 and Analog Devises AD2841 laser driver are presented. Typical extinction ratio obtained with these drivers was 10dB. Peak to peak jitter was <40ps. Dispersion penalty with these drivers transmission was found to be <1.9dB for the 650km of standard SMF-28 fiber (No dispersion compensation). Dispersion penalty vs transmission distance data will be presented. Results of the study of nonlinear effects in multi channels link will be reported. We observed that there was self phase modulation effect leading to reduction in dispersion power penalty. This effect can be to transmit single channel over distances longer then 650km. We showed that there was negligible crosstalk penalty and no FWM penalty. Threshold for stimulated Brillouin scattering was also investigated.