SECOND HARMONIC WAVE GENERATING ELEMENT AND ITS PRODUCTION

• Main Authors: NITANDA FUMIO, FURUKAWA YASUNORI, SATO MASAZUMI, MAKIO SATOSHI, ITOU AKITOMO, ITO KOHEI, KAWAMOTO KAZUTAMI
• Format: Patent
• Language: English
• Published: 06.05.1994
• Edition: 5
• Subjects: BASIC ELECTRIC ELEMENTS; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DEVICES USING STIMULATED EMISSION; ELECTRICITY; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PURPOSE:To provide polarity inversion gratings of an ideal rectangular shape and to generate SHG light with high efficiency by periodically arranging the polarity inversion regions extended from seed regions of polarization. CONSTITUTION:An LiTaO3 or LiNbO3 substrate 11 is used and proton exchange layer of grating patterns, i.e., seed regions of polarization, are first formed on the surface of this substrate 11 and are subjected to a heat treatment within 10 minute holding time at >=200 deg.C after pattern formation. The polarity inversion regions 12 are formed downward from the proton exchange regions by executing the heat treatment at >=50 deg.C/min temp. gradient up to the heat treatment temp. and >=50 deg.C/min temp. falling rate from the heat treatment temp. so that the front ends of these regions are sharpened and that the depth/width ratio of the formed polarity inversion gratings exceeds 1. As a result, the high-efficiency SHG element is obtd.