Co-integration of two DFB lasers on glass for millimeter-wave generation

In this work, we propose the realization of two single mode distributed feedback (DFB) lasers emitting at 1.5μm with ultra-narrow linewidths, co-integrated on a co-doped Erbium Ytterbium IOG1 1 glass substrate. The beating note of these two lasers on a fast photodiode is used to generate mm-wave signals. Each laser is composed of a waveguide fabricated by ion exchange with a Bragg grating etched on the top. In order to set a precise value of the mm-wave frequency, the emission wavelength of both DFB lasers must be accurately fixed. This is achieved by controlling the laser’s waveguide design. The beating produced between these lasers generates mm-wave signals from GHz to THz. The co-integration helps to enhance the beating quality by reducing fluctuations between the two lasers. Lasers are first studied independently: their optical power, linewidth and relative intensity noise are characterized. Finally, the beating signal quality is estimated through the characterization of the produced electrical spectrum.