dorsal/arxiv
View SchemaMeasurements of the instantaneous velocity difference and local velocity with a fiber-optic coupler
| Authors | S. H. Yao, V. K. Horváth, P. Tong, B. J. Ackerson, W. I. Goldburg |
|---|---|
| Categories | |
| ArXiv ID | physics/0010021 |
| URL | https://arxiv.org/abs/physics/0010021 |
| DOI | 10.1364/JOSAA.18.000696 |
Abstract
New optical arrangements with two single-mode input fibers and a fiber-optic coupler are devised to measure the instantaneous velocity difference and local velocity. The fibers and the coupler are polarization-preserving to guarantee a high signal-to-noise ratio. When the two input fibers are used to collect the scattered light with the same momentum transfer vector but from two spatially separated regions in a flow, the obtained signals interfere when combined via the fiber-optic coupler. The resultant light received by a photomultiplier tube contains a cross-beat frequency proportional to the velocity difference between the two measuring points. If the two input fibers are used to collect the scattered light from a common scattering region but with two different momentum transfer vectors, the resultant light then contains a self-beat frequency proportional to the local velocity at the measuring point. The experiment shows that both the cross-beat and self-beat signals are large and the standard laser Doppler signal processor can be used to measure the velocity difference and local velocity in real time. The new technique will have various applications in the general area of fluid dynamics.
{
"annotation_id": "5a959462-fc06-4a9b-8b91-b78e5448fb70",
"date_created": "2026-03-02T18:00:32.601000Z",
"date_modified": "2026-03-02T18:00:32.601000Z",
"file_hash": "95bfc4e51ea66e361edc8d5f29739383f9af0713a134d46fddf302f83b2f068e",
"private": false,
"record": {
"abstract": "New optical arrangements with two single-mode input fibers and a fiber-optic\ncoupler are devised to measure the instantaneous velocity difference and local\nvelocity. The fibers and the coupler are polarization-preserving to guarantee a\nhigh signal-to-noise ratio. When the two input fibers are used to collect the\nscattered light with the same momentum transfer vector but from two spatially\nseparated regions in a flow, the obtained signals interfere when combined via\nthe fiber-optic coupler. The resultant light received by a photomultiplier tube\ncontains a cross-beat frequency proportional to the velocity difference between\nthe two measuring points. If the two input fibers are used to collect the\nscattered light from a common scattering region but with two different momentum\ntransfer vectors, the resultant light then contains a self-beat frequency\nproportional to the local velocity at the measuring point. The experiment shows\nthat both the cross-beat and self-beat signals are large and the standard laser\nDoppler signal processor can be used to measure the velocity difference and\nlocal velocity in real time. The new technique will have various applications\nin the general area of fluid dynamics.",
"arxiv_id": "physics/0010021",
"authors": [
"S. H. Yao",
"V. K. Horv\u00e1th",
"P. Tong",
"B. J. Ackerson",
"W. I. Goldburg"
],
"categories": [
"physics.flu-dyn",
"astro-ph",
"cond-mat.soft",
"physics.ins-det",
"physics.optics"
],
"doi": "10.1364/JOSAA.18.000696",
"title": "Measurements of the instantaneous velocity difference and local velocity with a fiber-optic coupler",
"url": "https://arxiv.org/abs/physics/0010021"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "cd024f24-d16a-4657-9f50-3ae2467adf1d",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}