Patent ID: 9671559
Date: 2017-06-06
CPC Classifications: G02B,H04B

Claim:
1. An optical apparatus comprising: a first directional coupler having a first waveguide and a second waveguide; a second directional coupler having a third waveguide and a fourth waveguide such that the third waveguide is optically connected with the second waveguide of the first directional coupler; a photodiode optically connected with an end of the third waveguide of the second directional coupler; wherein the first directional coupler is configured to, in response to receiving an input signal having a first polarization and a second polarization, output onto the second waveguide a first optical mode having the first polarization and the second polarization; wherein the second directional coupler is configured to output a second optical mode having a majority of the first polarization onto the third waveguide; and wherein the third waveguide and the fourth waveguide are not optically coupled to the first waveguide.