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A cascaded silicon Raman laser


One of the major advantages of Raman lasers is their ability to generate coherent light in wavelength regions that are not easily accessible with other conventional types of lasers1. Recently, efficient Raman lasing in silicon in the near-infrared region has been demonstrated2,3,4, showing great potential for realizing low-cost, compact, room-temperature lasers in the mid-infrared region5,6,7. Such lasers are highly desirable for many applications, ranging from trace-gas sensing, environmental monitoring and biomedical analysis, to industrial process control, and free-space communications8,9. Here we report the first experimental demonstration of cascaded Raman lasing in silicon, opening the path to extending the lasing wavelength from the near- to mid-infrared region. Using a 1,550-nm pump source, we achieve stable, continuous-wave, second-order cascaded lasing at 1,848 nm with an output power exceeding 5 mW. The laser operates in single mode, and the laser linewidth is measured to be <2.5 MHz.

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Figure 1: The cascaded silicon Raman laser.
Figure 2: Schematic set-up of the cascaded silicon Raman laser experiment.
Figure 3: The first- and second-order silicon Raman laser output power as a function of the waveguide coupled input pump power.
Figure 4: Cascaded silicon Raman laser output spectrum.
Figure 5: Methane and water vapour absorption spectra measured with the cascaded silicon Raman laser.


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We thank Y.-H. Kuo for contributions in ring resonator development; A. Alduino, D. Tran, J.C. Jimenez, N. Izhaky, N. Ziharev and J. Ngo for assistance in device fabrication and sample preparation; W.B. Chapman for helpful suggestions regarding molecular spectroscopy; and R. Jones, A. Liu, J. Doylend, G.T. Reed and J.E. Bowers for technical discussions.

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Correspondence to Haisheng Rong.

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Rong, H., Xu, S., Cohen, O. et al. A cascaded silicon Raman laser. Nature Photon 2, 170–174 (2008).

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