Multibeam visar using image coupling from one optical fiber bundle to another through the visar interferometer

• Main Author: BARKER; LYNN M
• Format: Patent
• Language: English
• Published: 09.02.1999
• Edition: 6
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION,OR SHOCK; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; TESTING

A multi-beam Velocity Interferometer System for Any Reflector (VISAR) which can measure velocity histories at multiple locations simultaneously. A VISAR's interferometer accepts laser signal light which has been reflected from a specimen surface, and produces light fringes in proportion to the reflecting surface velocity by virtue of the Doppler shift in wavelength. The invention uses a reflected-light fiber optic bundle to supply the signal light for the VISAR. The bundle has multiple optical fibers, each carrying light reflected from a separate measurement location. The light emerging from the reflected-light fiber bundle is transformed into a beam by a collimator. The beam travels through the conventional VISAR interferometer, emerging usually in two or four exit beams. Imaging optics in the exit beams, together with the collimator, create real images of the end of the reflected-light fiber bundle. The light reflected from the different locations of measurement is not segregated while traversing the interferometer. However, in the exit beam images, the light from each individual reflected-light optical fiber is resegregated, and forms the separate images of the ends of the individual fibers. This allows the separated signals from each location of measurement to be recaptured and sent to assigned light detectors for sensing, recording, and later data reduction to velocities vs. time. The multi-beam VISAR preserves the high-quality optical fringes, accuracy, and ease-of-use features of many former VISARs, and is capable of economically measuring at least tens of locations simultaneously.