LiNbO3 Electro-optic Modulator Research Articles

Minimizing dc drift in LiNbO3 waveguide devices

Improved stability against electrical dc bias drift has been demonstrated in LiNbO3 electro-optic modulators by replacing the commonly used SiO2 buffer layer with indium tin oxide (ITO), a transparent conductor. The long term drift of the modulators having an ITO buffer layer with a sheet resistivity of ∼20 Ω/⧠ is less than 0.3% in 8 h. The mechanism of the dc drift phenomenon is discussed using an electrical equivalent circuit model of the modulator.

LiNbO3 electro-optic light modulator performing 100% intensity modulation at 550 MHz

An electro-optic light modulator using a LiNbO3 crystal of large cross section (1.5 × 1.5 mm2) is described. The LiNbO3 crystal is placed in a 3λM/4 coaxial cavity and may be biased by a dc voltage. 100% intensity modulation at a frequency νM=550 MHz is achieved by maintaining the good optical quality of the modulator. The simple arrangement permits the modulation of light of large spectral width without requiring temperature control.

LiNbO3 electro-optic modulator and switch

We demonstrate an experimental electro-optical modulator/switch based on the principle of coupled guided waves with adjustable coupling gap and interaction length. The maximum extinction ratio observed was −20 dB.

A 964-GHz TRAVELING-WAVE ELECTRO-OPTIC LIGHT MODULATOR

A 0.633-μ m laser has been modulated at 964 GHz (311 μ m) and 891 GHz (337 μ m) by a novel phase-matched LiNbO3 electro-optic modulator driven by an HCN laser. The performance of the modulator agrees with calculations based on the radio-frequency electro-optic coefficient. Similar experiments with a CdS modulator were unsuccessful presumably because of the generation of photocarriers.