Measurement method of a half-wavelength voltage for Mach-Zehnder optical modulators in wireless communication and broadcasting systems

2009 ◽  
Keyword(s):  
Wireless Communication ◽  
Measurement Method ◽  
Optical Modulators ◽  
Half Wavelength

scholarly journals Optical Acceleration Measurement Method with Large Non-ambiguity Range and High Resolution via Synthetic Wavelength and Single Wavelength Superheterodyne Interferometry

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3417 ◽  
Author(s):  
Qianbo Lu ◽  
Dexin Pan ◽  
Jian Bai ◽  
Kaiwei Wang
Keyword(s):  
High Resolution ◽  
Measurement Method ◽  
Phase Measurement ◽  
Optical Modulators ◽  
Acceleration Measurement ◽  
Real Time Measurement ◽  
Narrow Bandwidth ◽  
Measurement Resolution ◽  
Good Agreement ◽  
Optical Acceleration

Interferometric optomechanical accelerometers provide superior resolution, but the application is limited due to the non-ambiguity range that is always less than half of the wavelength, which corresponds to the order of mg. This paper proposes a novel acceleration measurement method based on synthetic wavelength and single wavelength superheterodyne interferometry to address this issue. Two acousto-optical modulators and several polarizers are introduced to the two-wavelength interferometry to create four beams with different frequencies and polarization states, and two ultra-narrow bandwidth filters are used to realize the single wavelength measurement simultaneously. This technique offers the possibility to expand the non-ambiguity range without compromising the high resolution. Also, the superheterodyne phase measurement and the corresponding processing algorithm are given to enable real-time measurement. A prototype is built and the preliminary experimental results are compared with the simulation results, showing good agreement. The results prove an estimated acceleration measurement resolution of around 10 μg and a non-ambiguity range of larger than 200 mg, which is more than 100 times that of the single wavelength-based optical accelerometer.

New polarized-light microscope for fast and orientation independent measurement of birefringent fine structure

1993 ◽  
Vol 51 ◽  
pp. 82-83
Author(s):  
Rudolf Oldenbourg
Keyword(s):  
Light Microscope ◽  
Polarized Light ◽  
Video Camera ◽  
Limited Range ◽  
Image Point ◽  
Computer Assisted ◽  
Optical Modulators ◽  
Anisotropic Structures ◽  
Long Time ◽  
Computer Assisted Image

The polarized light microscope has the unique potential to measure submicroscopic molecular arrangements dynamically and non-destructively in living cells and other specimens. With the traditional pol-scope, however, single images display only those anisotropic structures that have a limited range of orientations with respect to the polarization axes of the microscope. Furthermore, rapid measurements are restricted to a single image point or single area that exhibits uniform birefringence or other form of optical anisotropy, while measurements comparing several image points take an inordinately long time.We are developing a new kind of polarized light microscope which combines speed and high resolution in its measurement of the specimen anisotropy, irrespective of its orientation. The design of the new pol-scope is based on the traditional polarized light microscope with two essential modifications: circular polarizers replace linear polarizers and two electro-optical modulators replace the traditional compensator. A video camera and computer assisted image analysis provide measurements of specimen anisotropy in rapid succession for all points of the image comprising the field of view.

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