PURPOSE: To obtain a wavelength multiple holography recorder which is made short in coherence length, allows the utilization of a wavelength variable LD of small output at a light source and is small in size and easy to handle by using optical systems of a symmetrical type and approximating the optical path difference between signal light and reference light to zero. ;CONSTITUTION: A laser beam 2 from the wavelength variable LD 1 is subjected to directional adjustment by mirrors 3, 5 and after the beam diameter is adjusted by a beam expander 4, this laser beam is spectrally split to the reference light 7 and the signal light 8. The reference light 7 and the signal light 8 are passed respectively through shutters 9, 10 and are projected by mirrors 11, 12 to a photorefractive crystal 16, by which interference fringes are formed. The optical systems are symmetrically arranged in such a manner that the optical path quantities of the reference light 7 and the signal light 8 are decreased. The reference light 7 forms interference fringes of a high contrast with the signal light by an ND filter 13 and a beam expander 14. The multiple recording is executed by changing the wavelength of the LD 1 and changing the modulation patterns of the signal light 8.;COPYRIGHT: (C)1996,JPO
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