Patent ID: 6424454
Filing Date: 2002-07-23
Classification: G02B,G02F

Abstract:
An apparatus for optical frequency conversion using a specially cut uncoated birefringent crystal with a primary optical (X-axis) wherein a first input wavelength and a second input wavelength polarized along the Z axis combine within said birefringent crystal by the sum-frequency process to generate a third, shorter wavelength polarized along the Y, said apparatus comprised of:a first input coupler prism 1 having an input face normal to the propagation direction of said input wavelengths with anti-reflection coatings matched to said input wavelengths and an output Brewster-cut face such that said input wavelengths are completely transmitted through said input coupler prism; a specially cut birefringent crystal 4 having a Brewster-cut input end adjacent to said first input coupler prism, a first output end having a Brewster-cut face such that said input wavelengths pass through and out of said birefringent crystal while said third wavelength is partially reflected to a third Brewster-cut face configured to transmit said third wavelength out of said birefringent crystal; a first output coupler prism 2 adjacent to said first output end of said birefringent crystal and having an input Brewster-cut face configured to transmit said input wavelengths and to reflect said third wavelength and coated with anti-reflection coatings matched to said input wavelengths and a high-reflection coating matched to said third wavelength and, further, having an output face normal to said input wavelengths with anti-reflection coatings matched to said input wavelengths; a second output coupler prism 3 adjacent to a second output end of said birefringent crystal and having an input Brewster-cut face configured to transmit said third wavelength and having an output face normal to said third wavelength with an anti-reflection coating matched to said third wavelength, thereby facilitating the transmission of said third wavelength out of said birefringent crystal.