Millimeter-wave laser modulation using III-V semiconductor travelling wave electro-optic Mach-Zehnder interferometer structures

It is expected that Wavelength Division Multiplex (WDM) fiber optic communications will be providing the high-speed backbone for the networks of the future. At the transmitter end, external laser modulation remains the approach of choice when high quality performance with reduced chirp is required at extra-high frequencies. Semiconductor based external laser modulators have the advantage of potential integration with the laser on the same substrate. On chip integration resolves the polarization sensitivity problem of the modulator, but is technologically more difficult to implement, often requiring material re-growth or ion-implantation [1] to ensure the transparency of the optical waveguides.