Patent ID: 8908281

Claim:
An optical splitting device comprising: a substrate, wherein an anti-reflective coating is disposed on an upper surface of the substrate and a filter membrane is disposed at a lower surface of the substrate, wherein the substrate has an at least approximately constant thickness that separates the anti-reflective coating and the filter membrane, and wherein the anti-reflective coating and the filter membrane are parallel; and a light redirecting portion disposed opposite to the filter membrane, wherein the anti-reflective coating is disposed between the light redirecting portion and the substrate, and wherein the light redirecting portion is spaced apart from the anti-reflective coating by a distance, wherein the filter membrane is configured such that when an optical signal is incident to the filter membrane at a first specified angle, a light wave of a first wavelength in the optical signal penetrates the filter membrane such that the light wave of the first wavelength is separated from the optical signal, and a light wave other than the light wave of the first wavelength is reflected by the filter membrane to the light redirecting portion, wherein the light redirecting portion is configured to enable the light wave reflected to the light redirecting portion to be incident to the filter membrane at a second specified angle, wherein the filter membrane is configured such that when a light wave of a second wavelength in the optical signal penetrates the filter membrane, the light wave of the second wavelength is separated from the optical signal, wherein the second specified angle is different from the first specified angle, wherein the filter membrane is configured such that when the first specified angle is an incident angle at which the optical signal is incident to the filter membrane, the filter membrane allows the penetration of the light wave of the first wavelength, and wherein the filter membrane is configured such that when the second specified angle is an incident angle at which the optical signal is incident to the filter membrane, the filter membrane allows the penetration of the light wave of the second wavelength.