A scheme to generate tunable dual-wavelength picosecond pulses by harmonic and rational-harmonic mode locking of a 1.5-µm Fabry–Perot grating-lens external-cavity laser has been proposed and experimentally demonstrated. The external cavity consists of a weak Fabry–Perot filter, a diffraction grating, a converging lens, and a totally reflecting mirror. Active mode locking has been achieved simultaneously at two different wavelengths in the semiconductor laser over a range of 65 nm. Dual-wavelength pulses with a spectral separation of 0.9 nm, a side-mode suppression ratio greater than 24 dB, and a pulse width of ∼30 ps have been generated. The relative intensity variation between the two lasing wavelengths is smaller than 1.2 dB, without any observable mode hopping. Frequency multiplication of the dual-wavelength pulse train with rational-harmonic mode locking has also been demonstrated. With a 2.5-GHz modulation frequency applied to the semiconductor laser, the pulse repetition rate was multiplied to 5.0 GHz. A total of 10.0 GHz ( wavelength channels) optical pulses was obtained. To the authors’ knowledge, this is the first report of multiple-wavelength rational-harmonic mode locking of a semiconductor laser.
© 1999 Optical Society of AmericaFull Article | PDF Article
P. J. Delfyett, G. A. Alphonse, J. C. Connolly, C.-H. Lee, L. T. Florez, N. G. Stoffel, T. J. Gmitter, and N. C. Andreadakis
Opt. Lett. 15(23) 1371-1373 (1990)
Alan Mar, Rong-Ting Huang, David Wolf, Dennis Derickson, Roger Helkey, and John Bowers
Opt. Lett. 17(12) 868-870 (1992)
Shin Arahira, Saeko Oshiba, Yasuhiro Matsui, Tatsuo Kunii, and Yoh Ogawa
Opt. Lett. 19(11) 834-836 (1994)