Laser interferometer with low-frequency phase modulation

1982 ◽  
Vol 12 (7) ◽  
pp. 827-832
Author(s):  
V P Kir'yanov ◽  
V P Koronkevich
Keyword(s):  
Phase Modulation ◽  
Laser Interferometer ◽  
Low Frequency ◽  
Frequency Phase

Mode-locked multi-wavelength fiber ring laser using low frequency phase modulation

2011 ◽  
Author(s):  
Chang Su Jun ◽  
Jae Kwon Ko ◽  
Sang Hwa Yoo ◽  
Byoung Yon Kim
Keyword(s):  
Phase Modulation ◽  
Ring Laser ◽  
Low Frequency ◽  
Fiber Ring Laser ◽  
Fiber Ring ◽  
Multi Wavelength ◽  
Frequency Phase

scholarly journals Interferometers with Internal and External Phase Modulation: Experimental and Analytical Comparison

1995 ◽  
Vol 48 (6) ◽  
pp. 971 ◽  
Author(s):  
Andrew J Stevenson ◽  
Malcolm B Gray ◽  
Charles C Harb ◽  
David E McClelland ◽  
Hans-A Bachor
Keyword(s):  
Shot Noise ◽  
High Frequency ◽  
Phase Modulation ◽  
Low Frequency ◽  
Local Oscillator ◽  
Intensity Noise ◽  
Fringe Contrast ◽  
Limited Region ◽  
External Modulation ◽  
Frequency Phase

Optical intensity noise in a light source easily degrades the sensitivity of a shot-noise-limited interferometer which is directly detecting low frequency phase or displacement variations. In this paper we describe and compare two experimental methods in which we use high frequency optical phase modulation to shift low frequency phase signals in an interferometer to a shot noise limited region of the photocurrent spectrum. This phase modulation is applied either within the interferometer arms-internal modulation-or in a local oscillator beam tapped off the main interferometer and coherently recombined with the interferometer output-external modulation. he photocurrent is mixed electronically with the high frequency modulating waveform to extract the signal information free from laser intensity noise. In our experiments, we have been able to detect interferometrically low frequency signals with true shot-noise-limited sensitivity. We find, theoretically and experimentally, that the interferometric sensitivity achievable in each scheme depends critically on non-ideal factors, such as imperfect interferometric fringe contrast and electronic noise in the detectors or amplifiers. This paper examines the relative merits and operating requirements of both modulation schemes in practical interferometers.

The Influence of Air-Bearing Surface Geometry on the Dynamics of Sliders

1992 ◽  
Vol 114 (1) ◽  
pp. 26-31 ◽  
Author(s):  
M. Suk ◽  
T. Ishii ◽  
D. Bogy
Keyword(s):  
Surface Defect ◽  
Laser Interferometer ◽  
Low Frequency ◽  
Frequency Component ◽  
Flying Height ◽  
Disk Drives ◽  
Bearing Surface ◽  
Surface Geometry ◽  
Spacing Variation ◽  
Slider Motion

We investigate the influence of crown on slider dynamics during the takeoff stages of disk drives using the multi-channel laser interferometer. We show that a two-dimensional analysis of slider dynamics during takeoff/landing cannot explain all the observed phenomena. We also examine the crown effect on slider motion while it is flying on a thin film disk with a crater-like surface defect. Finally, we measure the spacing variation of the slider as a function of disk speed. It is observed that the initial motion of negative crown sliders during takeoff can be quite similar to positive crown sliders, although the process is quite different. Furthermore, the results suggest that the negative crown sliders may lead to more disk wear due to longer sliding distances. We observed that during steady flying conditions the craterlike surface defect on the disk produced significantly larger motions for negative crown sliders than positive crown sliders. Lastly, we found that both the waveform and magnitude of the low frequency component of the spacing fluctuation is independent of the slider flying height.

scholarly journals Auditory Cortex Tracks Both Auditory and Visual Stimulus Dynamics Using Low-Frequency Neuronal Phase Modulation

PLoS Biology ◽  
2010 ◽  
Vol 8 (8) ◽  
pp. e1000445 ◽  
Author(s):  
Huan Luo ◽  
Zuxiang Liu ◽  
David Poeppel
Keyword(s):  
Auditory Cortex ◽  
Visual Stimulus ◽  
Phase Modulation ◽  
Low Frequency

Squeezing-enhanced fiber Mach-Zehnder interferometer for low-frequency phase measurement

2017 ◽  
Vol 110 (2) ◽  
pp. 021106 ◽  
Author(s):  
Fang Liu ◽  
Yaoyao Zhou ◽  
Juan Yu ◽  
Jiale Guo ◽  
Yang Wu ◽  
...  
Keyword(s):  
Phase Measurement ◽  
Low Frequency ◽  
Zehnder Interferometer ◽  
Frequency Phase ◽  
Mach Zehnder Interferometer

Interferometer with two-frequency phase modulation

1994 ◽  
Author(s):  
Ilya S. Etsin ◽  
Michael G. Arkipov ◽  
Alexander G. Seregin
Keyword(s):  
Phase Modulation ◽  
Frequency Phase
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