Monolithic silicon crystal waveguides for tunable wavelength laser light from stimulated Raman scattering

Stimulated Raman scattering (SRS) captures and amplifies light, a process that can be further enhanced by exploiting silicon photonics. This technology describes a silicon photonic crystal with a lattice of air holes that is configured to receive pump light and to output Stokes light through Raman scattering. Lithographically patterned line defects form a waveguide to facilitate Raman lasing in specially dimensioned lattices, allowing wavelength manipulation beyond material norms. Additionally, using silicon-based materials enables low-cost integration of photonics into complementary metal oxide semiconductor (CMOS) chips, as well as new lasing techniques for high speed optical switching.

Waveguides are mechanically tunable and can function in a wide range of applications

This technology is the first SRS photon generating method that can successfully be integrated into a CMOS chip and used as a single wavelength lasing source. By tuning the periodicity and size of the holes in the silicon crystal, the wavelength of the SRS photons generated can be finely tuned. In addition to functioning as laser sources, the waveguides can be integrated with CMOS to form fast and effective optically switchable logic gates. This enables photonic and electronic integrated circuits to be used in photo-regulated signal processing or computing without the need for additional mechanical parts.

The tunability of the band gap of the waveguides was verified via transmission spectroscopy, while the laser emission was determined through simulations of the pump and emitted electric field.

Lead Inventor:

Chee Wei Wong, Ph.D.

Applications:

• Provides a method for a reliable Raman scattering-based laser
• Tunable laser devices in silicon electronic-photonic integrated circuits
• High speed optical switching
• Lasers with optimized wavelengths for multiple color fluorescence (i.e. FRET, flow cytometry)

Advantages:

• Enables low-loss and low-threshold Raman lasing and amplification in silicon
• Low pump power requirements
• Have great compatibility with silicon based optical systems
• The inherent ease of integration of a silicon photonics platform with complementary-metal-oxide-semiconductor foundries provides improved opportunities to reduce costs
• No additional mechanical parts are required

Patent information:

Patent Issued (US 7,869,470)

Patent Issued (US 8,287,642)

Patent Pending (WO/2007/027982)

Tech Ventures Reference: IR M05-098

Related Publications:

• X. Yang, C.W. Wong. Design of photonic band gap nanocavities for stimulated Raman amplification and lasing in monolithic silicon. Optics Express, Vol. 13, Issue 12, pp. 4723 - 4730.
• J. F. McMillan, X. Yang, N. C. Panoiu, R. M. Osgood, and C. W. Wong. Enhanced stimulated Raman scattering in slow-light photonic crystal waveguides. Optics Letters, Vol. 31, Issue 9, pp. 1235-1237 (2006).