Reflectometry by means of optical-coherence modulation

Hotate, Kazuo; Kamatani, O.

doi:10.1049/el:19891009

Cited by 42 publications

(26 citation statements)

References 4 publications

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“…The laser output frequency was sinusoidally modulated by direct modulation of the driving current [11,12,13,14,15,16,17,18,19,20]. The modulation frequency f m was swept from 5.52 MHz to 11.05 MHz with a repetition rate of 10 Hz.…”

Section: Methodsmentioning

confidence: 99%

“…One promising technique for mitigating these problems is optical correlation (or coherence)-domain reflectometry (OCDR) [11,12,13,14,15,16,17,18,19,20] using synthesized optical coherence function (SOCF) [18], which operates based on optical correlation control through modulated optical frequency of the laser output. Two methods have been reported to implement the frequency modulation: sinusoidal modulation [13,14,15] and stepwise modulation [16,17,18]. The latter includes the use of an optical frequency comb [19,20], which improves the measurement stability.…”

Section: Introductionmentioning

confidence: 99%

“…In a standard OCDR-SOCF system [13,14,15,16,17,18,19,20], the Fresnel spectrum is shifted by several tens of megahertz by optical heterodyne detection using an acousto-optic modulator (AOM) to avoid the overlap of low-frequency noise of the electrical devices. To perform electrical signal processing in the frequency range near direct current (DC), and thus to reduce the cost of the relevant devices, we have recently succeeded in excluding the optical heterodyne detection (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Simplified optical correlation-domain reflectometry using polymer fiber

Hayashi

Shizuka

Minakawa

et al. 2015

IEICE Electron. Express

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We develop a simplified configuration of optical correlation-(or coherence-) domain reflectometry (OCDR) using a polymer optical fiber (POF). The conventional reference light path is removed by using as reference light the Fresnel-reflected light caused at the interface between a silica single-mode fiber and the POF. We demonstrate its basic operation and investigate the dependences of the spatial resolution and signal-to-noise ratio (SNR) on the sweep time of the laser modulation frequency. The optimal sweep time is found to be 30 ms (corresponding to a repetition rate of 33 Hz), at which both the resolution and SNR are maintained at high values.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simplified optical correlation-domain reflectometry using polymer fiber

Hayashi

Shizuka

Minakawa

et al. 2015

IEICE Electron. Express

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“…In 1977, he became an Associate Professor at Yamagata University and was promoted to Professor in 1988. During 1989, he was an invited Professor at Munich University and an exchange Professor at the University of California, Berkeley, during [1989][1990]. He has been involved in research on laser oscillations, optical nonlinear effects, laser-radar, laser organic applications, optical waveguide memories, and phase conjugate optics.…”

Section: Discussionmentioning

confidence: 99%

Reproduction of optical reflection‐intensity‐distribution using multimode laser coherence

Tanno¹,

Ichimura²

1994

Electron Comm Jpn Pt II

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A new reflectometry method is proposed which enables measurements of light‐reflection‐distributions with spatial resolutions below tens of micrometers. the method can be applied to the detection of the damaged point of optical fibers, optical integrated circuits (ICs), reproduction of optical waveguide three‐dimensional memories, etc. By consideration of the coherency of a multimode laser, it becomes possible to construct the reflectometer without the need for frequency scanning of the optical source and movable parts. The interference light from the Michelson interferometer or from the interfaces of the multilayer object are analyzed (by the spectrometer) and square detected to obtain the interferospectrum of the interference light. Using the property that the interferospectrum is the duplicate of the reflection distribution, the Fourier inverse transform of the reflection distribution is carried out and the “spatialgram” is reproduced. the spatial resolution is determined by the inverse of the spectrumwidth of all modes. Therefore, even if a common multimode laser diode, available on the market with all‐mode spectrum‐width of 10 nm is used, the high resolution of about 34 μm can easily be achieved. Numerical results of the theoretical analysis of reflections, in the frequency domain, also are presented.

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“…We have shown that an optical coherence function can be synthesized in an interferometer by using direct frequency modulation characteristics of laser diodes (LDs) [10]. Additionally, we have also found that phase modulation in one arm of an interferometer allows the synthesis of arbitrary shapes of the optical coherence function [11].…”

Section: Synthesis Of Optical Coherence Functionmentioning

confidence: 99%

Coherent Photonic Sensing

Hotate

1999

Sensors Update

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Reflectometry by means of optical-coherence modulation

Cited by 42 publications

References 4 publications

Simplified optical correlation-domain reflectometry using polymer fiber

Simplified optical correlation-domain reflectometry using polymer fiber

Reproduction of optical reflection‐intensity‐distribution using multimode laser coherence

Coherent Photonic Sensing

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