An optical homodyne technique to measure photorefractive-induced phase drifts in lithium niobate phase modulators.
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.
Department of Electro-Optical Engineering, Southern Taiwan University1, Nan-Tai St., Yung-Kang City, Tainan 710, Taiwan, ROC. rctwu@mail.stut.edu.tw
Ruey-Ching
RC
Twu
Hao-Yang
HY
Hong
Hsuan-Hsien
HH
Lee
D000465:Algorithms; D016477:Artifacts; D019544:Equipment Failure Analysis / Q000379:methods*; D005583:Fourier Analysis; D007368:Interferometry / Q000379:methods*; D009556:Niobium / Q000737:chemistry*; D055095:Optics and Photonics / Q000295:instrumentation*; D010087:Oxides / Q000737:chemistry*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods*
D010087:Oxides; D009556:Niobium; C091692:lithium niobate