Polarizing function element, optical isolator, laser diode module and method of producing polarizing function element

• US 20030007251A1
• Filed: 05/20/2002
• Published: 01/09/2003
• Est. Priority Date: 09/20/2000
• Status: Active Grant

• Current Assignee: Namiki Seimitsu Houseki Kabushiki Kaisha
• Original Assignee: Namiki Seimitsu Houseki Kabushiki Kaisha
• Inventors: Sato, Toshimichi, Kasai, Yoshihito, Shiroki, Kenichi, Imaizumi, Nobuo
• Granted Patent: US 7,002,742 B2
• Time in Patent Office: Days
• US Class Current: 359/584
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 5/204 in which spectral selection is performed by means of a conductive grid or array, e.g. frequency selective surfaces for use with wavelengths longer than the infrared light H01Q15/0006
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: Y10S 359/90 Methods

Abstract

This invention has the polarizing function of polarizing an input beam and a non-reflecting function of suppressing reflection of the input beam, wherein at least one side of a light-transmissive substrate 1 has a polarizing portion 4 with a striped structure formed by multiple alternating light-transmissive dielectric layers 2a, 2b . . . and metallic film layers 3a, 3b . . . . Its characteristics are improved if the metallic film layers are very thin and flat, with a target thickness in the range from 5 to 20 nm and variation of film thickness within the range of ±10%.

Claims

1. A polarization function element that has the polarizing function of polarizing an input beam and a non-reflecting function of suppressing reflection of the input beam, in which at least one side of a light-transmissive substrate has a polarizing portion with a striped structure formed by multiple alternating light-transmissive dielectric layers and metallic film layers.

2. A polarizing function element as described in claim 1 above, in which the metallic film layers are very thin and flat, having a target film thickness within the range from 5 to 20 nm and variation of film thickness within the range of ±

10%.

3. A polarizing function element as described in claim 1 or 2 above, in which one or more stacked portions is formed by stacking on the polarizing portion with light-transmissive dielectric layers.

4. A polarizing function element as described in claims 1 through 3 above, in which a Faraday rotator is used as the light-transmissive substrate.

5. An optical isolator that incorporates a polarizing function element as described in claim 4 above.

6. A laser diode module in which is mounted an optical isolator as described in claim 5 above.

7. A method of manufacturing a polarizing function element, in which there is a light-transmissive substrate, and after a base layer is formed on the substrate for the formation of a light-transmissive dielectric layer, multiple parallel parts of a base lattice are formed of a dielectric layer separated by a given interval, a metallic film layer is formed by vapor deposition at an angle on both sides of the base lattice, the residual intervals within the metal plated base lattice is filled with dielectric material, yielding a polarizing portion with a striped structure of dielectric layers and metallic film layers integrated with the substrate.

8. A method of manufacturing a polarizing function element as described in claim 7 above, in which the metallic film layer is deposited on both sides of the base lattice at angles that are different on each side of the base lattice.

9. A method of manufacturing a polarizing function element as described in claim 7 or 8 above, in which a polarizing portion with a striped structure of dielectric layers and metallic film layers, which are very thin and flat having a target film thickness within the range from 5 to 20 nm and variation of film thickness within the range of ±

10%, integrated with the substrate.