Low voltage, moderate rejection ratio electro-optic modulator at 2.2μm obtained by proton exchange in lithium niobate

In this paper we present the performances of a modulator, realized by proton exchange, achieving a moderate rejection ratio in the K-band (2.2μm). The device consists on a simple Mach-Zehnder beam combiner, developed by our partners from Photline Technologies®, pushing forward their proton exchange technique in order to achieve single mode optical guiding above 1.9μm in Lithium Niobate X-cut substrates. Applying low modulation voltages (V π =3.4V), and by a Fast Fourier Transform obtain the spectrum of the source with a moderate resolution, due to the reduced length of the active part (32mm). A white light interferometer is also shown, using a band-pass filter, from 1.8 to 2.6μm.