MICRO-FILTER STRUCTURES FOR WAVELENGTH DIVISION MULTIPLEXING IN POLYMER WAVEGUIDES

• US 20170269305A1
• Filed: 06/06/2017
• Published: 09/21/2017
• Est. Priority Date: 11/17/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hroux, Jean Benoit
• Granted Patent: US 10,168,482 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2006/12109 Filter
• CPC Class Codes: G02B 2006/12114 Prism
• CPC Class Codes: G02B 2006/12121 Laser
• CPC Class Codes: G02B 2006/12135 Temperature control
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/1221 made from organic materials
• CPC Class Codes: G02B 6/29364 Cascading by a light guide path between filters or filtering operations, e.g. fibre interconnected single filter modules
• CPC Class Codes: G02B 6/29368 Light guide comprising the filter, e.g. filter deposited on a fibre end G02B6/29359 takes precedence

Abstract

A wavelength division multiplexing filter and methods of forming the same include an optical dielectric filter having multiple dielectric layers. The optical dielectric filter has a high reflectivity at a first wavelength and a high transmissivity at one or more additional wavelengths. The dielectric layers include a structure of layers following the pattern L-[M/2-H-M/2]N-L, where L layers include a first dielectric material, H layers include a second dielectric material, M/2 layers have a mixture of the first and second dielectric material and have a thickness half that needed to provide reflectivity at the first wavelength, and N is a number of repetitions for the structure in brackets.

Claims

1. A wavelength division multiplexing filter, comprising:

an optical dielectric filter comprising a plurality of dielectric layers, said optical dielectric filter having a high reflectivity at a first wavelength and a high transmissivity at one or more additional wavelengths, wherein the plurality of dielectric layers comprise a structure of layers following the pattern L-[M/2-H-M/2]N-L, where L layers comprise a first dielectric material, H layers comprise a second dielectric material, M/2 layers comprise a mixture of the first and second dielectric material and have a thickness half that needed to provide reflectivity at the first wavelength, and N is a number of repetitions for the structure in brackets.

2. The filter of claim 1, further comprising a waveguide, wherein the optical dielectric filter is disposed in a transmission path of the waveguide.

3. The filter of claim 2, wherein the optical dielectric filter is disposed in a triangular groove of the waveguide and wherein there is no air gap in the transmission path.

4. The filter of claim 2, wherein the optical dielectric filter is disposed in a rectangular groove in the waveguide and wherein there is an air gap in the transmission path.

5. The filter of claim 2, wherein the waveguide is a polymer waveguide.

6. The filter of claim 1, wherein the optical dielectric filter is a Bragg mirror comprising either silicon dioxide and titanium dioxide or gallium arsenide and aluminum arsenide.

7. A wavelength division multiplexing system, comprising:

one or more waveguides, each comprising one or more wavelength-filtering prisms disposed in a transmission path of the respective waveguide, each wavelength-filtering prism comprising;

a Bragg mirror comprising a plurality of dielectric layers, each Bragg mirror having a high reflectivity at a respective first wavelength and a high transmissivity at one or more additional wavelengths, wherein the plurality of dielectric layers comprise a structure of layers following the pattern L-[M/2-H-M/2]N-L, where L layers comprise a first dielectric material, H layers comprise a second dielectric material, M/2 layers comprise a mixture of the first and second dielectric material and have a thickness half that needed to provide reflectivity at the first wavelength, and N is a number of repetitions for the structure in brackets.

8. The system of claim 7, wherein the one or more Bragg mirrors are disposed in respective triangular grooves of the waveguide and wherein there is no air gap in the transmission path.

9. The system of claim 7, wherein the one or more Bragg mirrors are disposed in respective rectangular grooves in the waveguide and wherein there is an air gap in the transmission path.

10. The system of claim 7, wherein the Bragg mirror comprises either silicon dioxide and titanium dioxide or gallium arsenide and aluminum arsenide.

11. The system of claim 7, further comprising a laser disposed over each Bragg mirror, configured to emit light at the respective first wavelength, wherein the respective Bragg mirror redirects the light at the respective first wavelength into the transmission path of the waveguide.

12. The system of claim 7, further comprising a photo-detector disposed over each Bragg mirror, configured to detect light at the respective first wavelength, wherein the respective Bragg mirror extracts the respective first wavelength from the transmission path and redirects said respective first wavelength to the photo-detector.

13. The system of claim 7, wherein the one or more waveguides further comprise a metal mirror disposed in the transmission path of the respective waveguide.

14. The system of claim 7, wherein the waveguide is a polymer waveguide.

15. A method for forming a wavelength division multiplexing filter, comprising:

depositing a plurality of dielectric layers on a substrate to form an optical dielectric filter having a high reflectivity at a first wavelength and a high transmissivity at one or more additional wavelengths, wherein the plurality of dielectric layers comprise a structure of layers following the pattern L-[M/2-H-M/2]N-L, where L layers comprise a first dielectric material, H layers comprise a second dielectric material, M/2 layers comprise a mixture of the first and second dielectric material and have a thickness half that needed to provide reflectivity at the first wavelength, and N is a number of repetitions for the structure in brackets;

cutting the substrate and the dielectric filter into a prism; and

placing the prism into a transmission path of a waveguide.

16. The method of claim 15, wherein there is no air gap in the transmission path.

17. The method of claim 15, cutting the substrate and the dielectric filter into a prism comprises cutting through a non-filtered side of the substrate with a 45-degree angle dicing saw or laser ablation.