Open AccessAn optical homodyne technique to measure photorefractive-induced phase drifts in lithium niobate phase modulators
Author(s) -
Ruey-Ching Twu,
Hao-Yang Hong,
Hsuan-Hsien Lee
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.004366
Subject(s) - photorefractive effect , lithium niobate , optics , phase modulation , phase (matter) , materials science , demodulation , interferometry , homodyne detection , fast fourier transform , optoelectronics , phase noise , physics , computer science , telecommunications , channel (broadcasting) , algorithm , quantum mechanics
In this paper, we develop an optical measurement system with capabilities of phase unwrapping, real-time and long-term monitoring for measuring a phase drift caused by photorefractive effects in lithium niobate phase modulators. To extract the phase-drift variations, the measurement setup uses a homodyne interferometer with a phase modulation and a Fast Fourier Transform (FFT) demodulation scheme. The phase-drift characteristics of a traditional Ti-indiffused and a Zn-indiffused phase modulator have been investigated under different applied voltages and throughput powers. These experiments were conducted as a proof-of-concept to demonstrate that the apparatus worked successfully to measure the phase drift of a device in the presence of photorefractive effects. The results indicate that the Zn-indiffused phase modulators have better photorefractive stability than the Ti-indiffused phase modulators.