CMOS-compatible multiple-wavelength oscillator for on-chip optical interconnects

Silicon photonics enables the fabrication of on-chip, ultrahigh-bandwidth optical networks that are critical for the future of microelectronics(1-3). Several optical components necessary for implementing a wavelength division multiplexing network have been demonstrated in silicon. However, a fully integrated multiple-wavelength source capable of driving such a network has not yet been realized. Optical amplification, a necessary component for lasing, has been achieved on-chip through stimulated Raman scattering(4,5), parametric mixing(6) and by silicon nanocrystals(7) or nanopatterned silicon(8). Losses in most of these structures have prevented oscillation. Raman oscillators have been demonstrated(9-11), but with a narrow gain bandwidth that is insufficient for wavelength division multiplexing. Here, we demonstrate the first monolithically integrated CMOS-compatible source by creating an optical parametric oscillator formed by a silicon nitride ring resonator on silicon. The device can generate more than 100 new wavelengths with operating powers below 50 mW. This source can form the backbone of a high-bandwidth optical network on a microelectronic chip.