• All-optical modulator is capable of terahertz speeds

    Researchers at the California Institute of Technology (CalTech; Pasadena, CA) have demonstrated intensity modulation of light with light, based on the all-optical Kerr effect in a planar, hybrid silicon-on-insulator/polymer, all-optical device.
    Nov. 1, 2006

    Researchers at the California Institute of Technology (CalTech; Pasadena, CA) have demonstrated intensity modulation of light with light, based on the all-optical Kerr effect in a planar, hybrid silicon-on-insulator/polymer, all-optical device. The group directly measured time-domain intensity modulation at 10 GHz and showed through spectral measurements that intensity modulation at frequencies in excess of 1 THz could be obtained. Integrating the optical polymer through evanescent coupling to the silicon waveguide increased the effective nonlinearity of the waveguide, allowing operation at continuous-wave power levels compatible with telecommunications requirements.

    The device was based on a Mach-Zehnder geometry, in which the source waveguide was split into two arms. A gate signal was introduced into one of the arms and induced a phase shift in the source signal via the nonlinear Kerr effect. Intensity modulation was accomplished through interference between the phase-shifted source signal and the optical signal traveling along the reference arm of the Mach-Zehnder interferometer. The interferometer was unbalanced to allow the intrinsic phase shift to be controlled by tuning the source wavelength, an ability that made the Mach-Zehnder easier to characterize. Contact Michael Hochberg at [email protected].

    Sign up for Laser Focus World Newsletters
    Get the latest news and updates.

    Voice Your Opinion!

    To join the conversation, and become an exclusive member of Laser Focus World, create an account today!