A continuous-wave Raman silicon laser

• Published in: Nature Vol. 433; no. 7027; pp. 725 - 728
• Main Authors: Liu, Ansheng, Paniccia, Mario, Rong, Haisheng, Jones, Richard, Cohen, Oded, Hak, Dani, Fang, Alexander
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 17.02.2005; Nature Publishing Group
• Subjects: Continuous operation; Exact sciences and technology; Fiber lasers; Fundamental areas of phenomenology (including applications); Laser optical systems: design and operation; Lasers; Nonlinear optics; Optics; Physics; Raman lasers; Silicon; Stimulated raman scattering; cars; CW lasers; Silicon; Semiconductor lasers; Output power; Raman lasers
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature03346

Achieving optical gain and/or lasing in silicon has been one of the most challenging goals in silicon-based photonics because bulk silicon is an indirect bandgap semiconductor and therefore has a very low light emission efficiency. Recently, stimulated Raman scattering has been used to demonstrate light amplification and lasing in silicon. However, because of the nonlinear optical loss associated with two-photon absorption (TPA)-induced free carrier absorption (FCA), until now lasing has been limited to pulsed operation. Here we demonstrate a continuous-wave silicon Raman laser. Specifically, we show that TPA-induced FCA in silicon can be significantly reduced by introducing a reverse-biased p-i-n diode embedded in a silicon waveguide. The laser cavity is formed by coating the facets of the silicon waveguide with multilayer dielectric films. We have demonstrated stable single mode laser output with side-mode suppression of over 55 dB and linewidth of less than 80 MHz. The lasing threshold depends on the p-i-n reverse bias voltage and the laser wavelength can be tuned by adjusting the wavelength of the pump laser. The demonstration of a continuous-wave silicon laser represents a significant milestone for silicon-based optoelectronic devices.