Optical bench on substrate and method of making the same

1. An optical bench comprising:

a substrate having a trench therein;

a light emitting device within the trench;

a light receiving device optically connected to the light emitting device;

at least one active circuit electrically connected to the light emitting device;

a waveguide in the trench, wherein the waveguide is optically between the light emitting device and the light receiving device; and

an optically transparent material between the light emitting device and the waveguide, the optically transparent material forming an interface with the light emitting device.

2. The optical bench of claim 1 , wherein the light receiving device is outside the trench.

3. The optical bench of claim 1 , wherein the at least one active circuit is outside the trench.

4. The optical bench of claim 1 , wherein the optically transparent material comprises spin-on glass, an organic material or a polymer material.

5. The optical bench of claim 1 , wherein the at least one active circuit is electrically connected to the light emitting device by a redistribution layer (RDL).

6. The optical bench of claim 1 , wherein the at least one active circuit is a plurality of active circuits.

7. The optical bench of claim 6 , further comprising a control system configured to selectively connect each active circuit of the plurality of active circuits to the light emitting device.

8. The optical bench of claim 1 , further comprising a reflector layer on a sloped side of the trench, wherein the light receiving device is positioned to receive light via the reflector layer.

9. The optical bench of claim 8 , wherein the optically transparent material forms an interface with the reflector layer.

10. The optical bench of claim 1 , wherein a side of the trench between the light emitting device and the at least one active circuit is substantially perpendicular to a top surface of the substrate.

11. An optical bench comprising:

a substrate having a trench therein;

a light emitting device on the substrate;

an electrically active light receiving device on the substrate, wherein the electrically active light receiving device is optically connected to the light emitting device, and one of the light emitting device or the electrically active light receiving device is in the trench;

a reflector layer over a sloped side of the trench, wherein the reflector layer is optically between the electrically active light receiving device and the light emitting device;

a waveguide in the trench, wherein the waveguide is optically between the light emitting device and the electrically active light receiving device; and

an optically transparent material against the light emitting device and the waveguide.

12. The optical bench of claim 11 , wherein the light receiving device is in the trench.

13. The optical bench of claim 11 , wherein the optically transparent material comprises a spin-on glass, an organic material or a polymer material.

14. The optical bench of claim 11 , further comprising an active circuit electrically connected to the light emitting device by a redistribution layer (RDL).

15. The optical bench of claim 11 , wherein the optically transparent material is in direct contact with the reflector layer.

16. The optical bench of claim 11 , wherein the reflector layer is between a bottom surface of the waveguide and the substrate.

17. The optical bench of claim 11 , further comprising an active circuit electrically connected to the electrically active light receiving device.

18. A method of making an optical bench, the method comprising:

forming a trench in a substrate;

mounting a light emitting device or a light receiving device in the trench, wherein the light emitting device is optically connected to the light receiving device;

mounting a waveguide in the trench; and

forming an optically transparent material between the light emitting device and the waveguide, the optically transparent material having an interface with the light emitting device and with the waveguide on a surface of the substrate.

19. The method of claim 18 , wherein mounting the light emitting device or the light receiving device in the trench comprises mounting both the light emitting device and the light receiving device in the trench.

20. The method of claim 18 , wherein forming the trench comprises forming the trench having a sloped side, and the method further comprises:

forming a reflector layer over the sloped side, wherein the reflector layer is optically between the light emitting device and the light receiving device.