Optical coupling devices

An optical multiplexing/demultiplexing device comprising:

• first and second graded index of refraction lenses each having opposing end surfaces with one end surface of each lens being in a spaced relationship;
• first and second filter elements disposed in the space between the lenses with their optical axes disposed at an angle with an absolute value in the range 170.degree.-179.5.degree., each of said elements being adapted to reflect incident light having a different predetermined wavelength and transmit the major portion of all other incident light;
• a curable adhesive disposed between the filter elements to maintain said angle;
• at least three optical transmission elements coupled to the surface of the first lens opposite to the filter elements, one of said transmission elements being adapted to transmit light having at least three wavelengths and the other two transmission elements each being adapted to transmit light of a different one of the wavelengths;
• and
• at least one optical transmission element coupled to the surface of the second lens opposite to the filter elements and adapted to transmit light of the third wavelength.

An optical four-port coupling device comprising:

• first and second graded index of refraction lenses each having opposing end surfaces with one end surface of each lens being in a spaced relationship;
• first and second partially reflecting elements disposed in the space between the lenses with their optical axes disposed at an angle with an absolute value in the range 170.degree.-179.5.degree.;
• a curable adhesive disposed between the reflecting elements to maintain said angle;
• first and second optical transmission elements coupled to the surface of the first lens opposite to the reflecting elements with the second transmission element being adapted to receive light from the first transmission element which is reflected from the first reflecting element;
• and
• third and fourth optical transmission elements coupled to the surface of the second lens opposite to the reflecting elements, with the third transmission element being adapted to receive light from the fourth transmission element which is reflected from the second filter element and also to receive light from the first transmission element which is transmitted through the two reflecting elements, the second transmission element being optically isolated from light from the fourth transmission element which is transmitted through the two reflecting elements.

A method of fabricating an optical device for diverting light from one transmission element to another comprising the steps of:

• positioning a pair of at least partially reflecting elements between first and second focusing elements, each having opposing end surfaces, by means of a curable adhesive;
• positioning a plurality of light transmission elements at the surfaces of the focusing elements opposite to the reflecting elements;
• adjusting the angle between the optical axes of the reflecting elements and positioning the transmission elements in order to maximize coupling between the transmission elements;
• and allowing the adhesive to cure in order to fix the angle between the reflecting elements.