Two-Color Dual-Beam Backscatter Laser Doppler Velocimeter

Watanabe

2014

SPIE Proceedings

A fiber-optic laser Doppler velocimeter (LDV) combining non-mechanical scanning and multipoint measurement is proposed for two-dimensional velocity distribution measurement on a cross-sectional plane. The LDV consists of a main body including a tunable laser and LiNbO 3 phase-shifter array, and a probe including diffraction gratings. The phaseshifter array is used to generate spatially encoded measurement points aligned in the transverse direction by multichannel optical serrodyne modulation, and these points are axially scanned with wavelength change. Two-dimensional velocitydistribution measurement is demonstrated using a probe setup with an 8-channel beam array.

Section: Introductionmentioning

confidence: 99%

Fiber optic laser Doppler velocimeter with non-mechanical scanning of spatially encoded points for cross-sectional velocity distribution measurement

Watanabe

2014

SPIE Proceedings

“…Velocity distribution has to be measured in many applications, and various techniques for mechanically scanning the measurement position have been reported [1][2][3][4][5][6]. A moving mechanism such as a moving lens [1], moving mirrors [2,3], a rotating diffraction grating [4], a rotating transparent plate [5], or rotating wedge prisms [6] is used in transmitting optics of these scanning LDVs.…”

Section: Introductionmentioning

confidence: 99%

Nonmechanical axial scanning laser Doppler velocimeter with directional discrimination

Hata

2012

Appl. Opt.

An axial scanning laser Doppler velocimeter (LDV) with directional discrimination not requiring any moving mechanism in its probe is proposed. The proposed LDV utilizes frequency shift induced by acousto-optic modulators (AOMs) for discriminating the direction of velocity. The measurement position is axially scanned by changing the wavelength of the light input to the probe. The experimental result reveals that both the axial scan and the directional discrimination can be realized by using the proposed method without any moving element in the probe.

“…Various techniques for mechanically scanning the measurement position, in which a moving mechanism is used in the transmitting optics, have been reported in order to measure the velocity distribution [1][2][3][4][5][6]. For practical applications, an LDV with a compact and easy-tohandle sensor probe is desirable.…”

Section: Introductionmentioning

confidence: 99%

Nonmechanical scanning laser Doppler velocimeter for cross-sectional two-dimensional velocity measurement

Hata

2012

Appl. Opt.

We propose a two-dimensional scanning laser Doppler velocimeter (LDV) that does not require any moving mechanisms in its probe. In the proposed LDV, the measurement position can be scanned in two dimensions on a cross-sectional plane perpendicular to the direction of flow. The combination of the change in wavelength and change in port of the fiber array input to the probe is utilized for the scan. The experimental results using a sensor probe setup indicate that the measurement position can be scanned in two dimensions using the proposed method. The scanning range was estimated to be 39.7 mm in the axial direction over the wavelength range of 1536-1554 nm and 26.1 mm in the transverse direction for the use of 22 ports of the fiber array.