The linewidth broadening of Distributed FeedBack (DFB) semiconductor lasers under direct modulation become more and more serious with the increase of modulating data rate. So it is important to investigate externally modulated transmitter module whose dynamic linewidth is the same as its static linewidth. The integrated module including DFB-LD and LN modulator reported here has a 3dB-bandwidth of 3.8 GHz , 4V drive voltage, and operating wavelength at I 548nm, its linewidth is about I 00MHZ measured by Gated Delay Seti Homodyne (GOSH) and 0-81 94-2292-4/96/$6.00 SPIE Vol. 2891 / 183 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx