Generation of coherent multicarrier signals by gain switching of discrete mode lasers

P. M. Anandarajah, R. Maher, Y. Q. Xu, S. Latkowski, J. O'Carroll, S. G. Murdoch, R. Phelan, J. O'Gorman, L. P. Barry

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113 Citations (Scopus)


The authors demonstrate the generation of a highly coherent multicarrier signal that consists of eight clearly resolved 10.7-GHz coherent sidebands generated within 3 dB of the spectral envelope peak and with an extinction ratio in excess of 45 dB by gain switching a discrete mode (DM) laser. The generated spectral comb displays a corresponding picosecond pulse train at a repetition rate of 10.7 GHz with a pulse duration of 24 ps and a temporal jitter of ∼450 fs. The optical spectra and associated pulses of the gain-switched DM laser are subsequently compared with a gain-switched distributed feedback (DFB) laser that generates a spectrum with no discernible sidebands and corresponding pulses with ∼3 ps of temporal jitter. By means of external injection, the temporal jitter of the gain-switched DFB laser is then reduced to < 1 ps, resulting in visible tones on the output spectrum. Finally, a nonlinear scheme is employed and initially tailored to compress the optical pulses, after which, the setup is slightly altered to expand the original frequency comb from the gain-switched DM laser.

Original languageEnglish
Article number5686909
Pages (from-to)112-122
Number of pages11
JournalIEEE Photonics Journal
Issue number1
Publication statusPublished - 9 Feb 2011
Externally publishedYes


  • Frequency combs
  • injection locked lasers
  • optical communications
  • pulse compression


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