Highly unbalanced GaAlAs–GaAs integrated Mach–Zehnder interferometer for coherence modulation at 1.3 μm
Résumé
A novel integrated III–V semiconductor waveguide modulator specially designed to generate an optical delay of 100 μm is presented. This is achieved by simultaneous propagation of the TE fundamental mode in both of the arms of a highly unbalanced Mach–Zehnder interferometer with a 29 μm length difference between both arms. In order to minimize the losses in this complex curved structure, trenches were etched on the outsides of curved sections. The modulator has a contrast of 34%, a switching voltage of 6 V with a 10 mm long electrode and is suitable for the transmission and multiplexing of signals by coherence modulation of light in an optical fiber network powered by a short coherence source, such as a 1.3 μm superluminescent diode.