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R u e y - C h i n g Tw u * , H o n g - Ya o H o u , a n d Yi - H u a n L e e
Department of Electro-Optical Engineering, Southern Taiwan University, Tainan 710, Taiwan
E-mail : [email protected]
STUT
In this study, a common-path optical homodyne polarization interferometer is proposed to demonstrate
the dual-wavelength phase measurements performed in a LabVIEW-based instrument. A Zn-indiffused
phase modulator (ZIPM) fabricated in an x-cut/z-propagation lithium niobate (LN) substrate that is used for
phase modulations of both wavelengths. The simultaneous phase measurements can be achieved by
utilizing the parallel processing and multiplexed capability in the LabVIEW platform. The experimental
results show that the simulated phases from the ZIPM can be extracted and real-time display shown on the
designed LabVIEW front panel.
P1, 2  1 / 2  1 / 2 cos(  1, 2 sin( 2ft )  1, 2 (t ))
 I1  J 2 ( ) 

 (t )  tan 
 I 2  J1 ( ) 
simu. (t )  (2  )n r Vdc ( L / G )
3
o 22
1
Fig. 1. The measurement setup.
Fig. 2. The designed LabVIEW front panel with a real-time display on
the measured data. All the analyzed signals and calculated results
including interferometric intensities (P), FFT spectrum, harmonic
intensities (I), ratio of different harmonic intensities, and phase
variations ( ) can be monitored with the flexible design of LabVIEW
front panel.
Fig. 3. Phase variations as a function of time under the
simulated applied voltages: (a) Vdc=2V and (b) Vdc=4V.
The phase curves are repeatable and the biases are
stable for the 632.8nm (1) wavelength. However, the
repeatable phase curves with gradually shifting biases
are observed for the 532nm (2) wavelength due to more
sensitivity photorefractive effect in the LN crystals.
We proposed and demonstrated a novel dual-wavelength phase measurement instrument by employing an
optical homodyne technique. The received signal and data process is performed in the LabVIEW platform.
Future work will demonstrate this instrument for a variety of industrial and scientific applications.
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