Ruey-Ching Twu

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Developments and applications of a dual-channel phase measurement system are being proposed and experimentally studied by utilizing an optical homodyne technique. In this measurement system, the phase modulation was adopted by using a near-stable Zn-indiffused lithium niobate phase modulator. The proposed method was successfully applied on the simultaneous(More)
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(More)
In this paper we have successfully demonstrated a z-propagating Zn-indiffused lithium niobate electro-optic modulator used for optical heterodyne interferometry. Compared to a commercial buck-type electro-optic modulator, the proposed waveguide-type modulator has a lower driving voltage and smaller phase variation while measuring visible wavelengths of 532(More)
A novel Zn-indiffused mode converter has been proposed and experimentally studied in an x-cut/z-propagation lithium niobate at a wavelength of 0.632 mum for the first time. The optimized phase-matching and mode-conversion voltages for maximum conversion are 12 V and -?5 V, respectively. The results show that the proposed mode converter can operate with a(More)
In this paper, an optical angle sensor with a birefringent transducer for measuring angular displacement based on a heterodyne interferometry is proposed. The achievable repeatability and linearity provide sufficient evidence for the practical use. As a result, a resolution of 5.8 ˆ 10 ́6 with a dynamic range of 5 ̋ has been achieved by utilizing a KTP(More)
An optical phase interrogation is proposed to study reflection-induced linear polarization rotation in a common-path homodyne interferometer. This optical methodology can also be applied to the measurement of the refractive index variation of a liquid solution. The performance of the refractive index sensing structure is discussed theoretically, and the(More)
We have fabricated and tested, to the best of our knowledge, the first fluidic birefringent sensor (FBS) for the concentration measurements of chemical solutions in a homodyne interferometer. The performance of KTP (potassium titanyl phosphate)-based FBS has been experimentally evaluated for successful concentration measurements in salt and hydrochloric(More)
Novel reflection-type homodyne chiral polarimetry is proposed for measuring the refractive index variations of a transparent plate under thermal impact. The experimental results show it is a simple and useful method for providing accurate measurements of refractive index variations. The measurement can reach a resolution of 7×10<sup>-5</sup>.
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