Laser speckle reduction by multimode optical fiber bundle with combined temporal, spatial, and angular diversity.

We report significant speckle reduction in a laser illumination system using a vibrating multimode optical fiber bundle. The optical fiber bundle was illuminated by two independent lasers simultaneously. The beams from both lasers were first expanded and collimated and were further divided into multiple beams to illuminate the fiber optic bundle with normal and oblique incidence. Static diffusers were also placed at the input and output faces of the fiber bundle, thus introducing the spatial as well as angular diversity of illumination. Experiments were carried out both in free space and in imaging geometry configuration. Standard deviation, speckle contrast and signal-to-noise ratio of the images were computed, and the results were compared with those of white light illumination. Speckle contrast close to that of white light was obtained using a vibrating fiber bundle with combined temporal, spatial, and angular diversities of the illumination.

[1]  Benedetto Daino,et al.  Speckle and Modal Noise in Optical Fibres Theory and Experiment , 1980 .

[2]  Reduction of speckle by a moving aperture - first order statistics , 1975 .

[3]  Yongmin Jung,et al.  Acousto-optic control of speckle contrast in multimode fibers with a cylindrical piezoelectric transducer oscillating in the radial direction. , 2009, Optics express.

[4]  J. Parry,et al.  Speckle contrast reduction in a large-core fiber delivering Q-switched pulses for fluid flow measurements. , 2006, Applied optics.

[5]  Yongmin Jung,et al.  Speckle Reduction in Near-field Image of Multimode Fiber with a Piezoelectric Transducer , 2008 .

[6]  Jahja I. Trisnadi.  Hadamard speckle contrast reduction. , 2004, Optics letters.

[7]  Victor Yurlov,et al.  Speckle suppression in scanning laser displays: aberration and defocusing of the projection system. , 2009, Applied optics.

[8]  S Kawata,et al.  Speckle-free image in a laser-diode microscope by using the optical feedback effect. , 1993, Optics letters.

[9]  Victor Yurlov,et al.  Speckle suppression in scanning laser display. , 2008, Applied optics.

[10]  Benedetto Daino,et al.  Analysis and measurement of modal noise in an optical fibre , 1979 .

[11]  Tatsuo Uchida,et al.  Speckle reduction mechanism in laser rear projection displays using a small moving diffuser. , 2010, Journal of the Optical Society of America. A, Optics, image science, and vision.

[12]  Toshimitsu Asakura,et al.  Mechanism of speckle reduction in laser-microscope images using a rotating optical fiber , 1985 .

[13]  Lingli Wang,et al.  Speckle reduction in laser projections with ultrasonic waves , 2000 .

[14]  T. Asakura,et al.  Speckle reduction in coherent information processing , 1996, Proc. IEEE.

[15]  Shigeo Kubota,et al.  Very efficient speckle contrast reduction realized by moving diffuser device. , 2010, Applied optics.

[16]  Peter L. Fuhr,et al.  Mode coupling and phase modulation in vibrating waveguides , 1992 .

[17]  Yoshihiro Ohtsuka,et al.  Laser speckle reduction by ultrasonic modulation , 1978 .

[18]  Y. Imai,et al.  Optical coherence modulation by ultrasonic waves. 2: Application to speckle reduction. , 1980, Applied optics.

[19]  Polarization modulation of light in an optical waveguide under lateral compression , 2006 .

[20]  Denis Joyeux,et al.  Speckle Removal by a Slowly Moving Diffuser Associated with a Motionless Diffuser , 1971 .

[21]  Yasuo Kitaoka,et al.  A practical laser projector with new illumination optics for reduction of speckle noise , 2004 .

[22]  Fringe contrast improvement in speckle photography by means of speckle reduction using vibrating optical fiber , 1986 .

[23]  B. Dingel.  Speckle Reduction with Virtual Incoherent Laser Illumination Using a Modified Fiver Array , 1993 .

[24]  J. Goodman.  Some fundamental properties of speckle , 1976 .

[25]  J. Goodman,et al.  Speckle-free rear-projection screen using two close screens in slow relative motion , 1976 .

[26]  J W Goodman,et al.  Analysis and measurement of the modal-noise probability distribution for a step-index optical fiber. , 1980, Optics letters.

[27]  F. D. de Mul,et al.  Suppression of dynamic laser speckle signals in multimode fibers of various lengths. , 2004, Applied optics.

[28]  Guangmin Ouyang,et al.  Laser speckle reduction due to spatial and angular diversity introduced by fast scanning micromirror. , 2010, Applied optics.

[29]  Zhaomin Tong,et al.  Speckle reduction in line-scan laser projectors using binary phase codes. , 2010, Optics letters.

[30]  T. Tschudi,et al.  Speckle reduction in laser projection systems by diffractive optical elements. , 1998, Applied optics.

[31]  Anatoliy Lapchuk,et al.  Speckle suppression in laser display using several partially coherent beams. , 2009, Optics express.

[32]  Toshimitsu Asakura,et al.  Reduction of coherent noise using various artificial incoherent sources , 1985 .