Abstract

Mid-infrared wideband modulation (3.2–3.7 μm) is achieved in an electro-optic Y-junction using lithium niobate waveguides in TE polarized light. Comparison between external (scanning mirror) and internal (electro-optical) modulation allows studying the chromatic polynomial dependence of the relative phase. Internal modulation consists on a $V_{\mathrm{AC}}$ ramp up to 370 V at 0.25 Hz, applied over 14 mm long electrodes with 14 μm separation. The overall $V_{\pi }{L}_{\pi }$ obtained is 17.5 V·cm, meaning that using a 300 V generator we can actively scan and track the whole L-band (3.4–4.1 μm) wideband fringes. We observe a dramatic reduction of the coherence length under electro-optic modulation, which is attributed to a strong nonlinear dependence of the electro-optic effect on the wavelength upon application of such high voltages. We study the effect of applying a $V_{\mathrm{DC}}$ offset, from $-50\mathrm{V}$ to 200 V (50 V step). We characterize this dispersion and propose an improved dispersion model that is used to show active dispersion compensation in wideband fringe modulation in the mid-infrared. This can be useful for long baseline interferometry or pulse compression applications when light propagates along fibers, in order to compensate for chromatic effects that induce differential dispersion or pulse spreading, respectively.

© 2017 Optical Society of America

Method for in-depth characterization of electro-optic phase modulators

Bassem Arar, Max Schiemangk, Hans Wenzel, Olaf Brox, Andreas Wicht, Achim Peters, and Günther Tränkle
Appl. Opt. 56(4) 1246-1252 (2017)

Mid-infrared integrated waveguide modulators based on silicon-on-lithium-niobate photonics

Jeff Chiles and Sasan Fathpour
Optica 1(5) 350-355 (2014)

Spectrally controlled interferometry

Chase Salsbury and Artur G. Olszak
Appl. Opt. 56(28) 7781-7788 (2017)

Control of residual amplitude modulation in Lithium Niobate phase modulators

John F. Diehl, Christopher E. Sunderman, Joseph M. Singley, Vincent J. Urick, and Keith J. Williams
Opt. Express 25(26) 32985-32994 (2017)

Dispersion analysis and measurement of potassium tantalate niobate crystals by broadband optical interferometers

Jian Ren
Appl. Opt. 56(2) 234-238 (2017)