Silicon photonics based fiber coupler
A silicon-based edge coupler for coupling a fiber with a waveguide includes a cantilever member being partially suspended with its anchored end coupled to a silicon photonics die in a first part of a silicon substrate and a free end terminated near an edge region separating a second part of the silicon substrate from the first part. The edge coupler further includes a mechanical stopper formed at the edge region with a gap distance ahead of the free end of the cantilever member. Additionally, a V-groove is formed in the second part of the silicon substrate characterized by a top opening and a bottom plane symmetrically connected by two sloped side walls along a fixed Si-crystallography angle. The V-groove is configured to support a fiber with an end facet being pushed against the mechanical stopper and a core center being aligned with the free end of the cantilever member.
1. A silicon photonics module comprising:
a silicon photonics die disposed on a substrate, the silicon photonics die comprising a waveguide; and
an optical coupler disposed along an edge of the silicon photonics die, the optical coupler extending from the edge of the silicon photonics die inwards towards the waveguide disposed in the silicon photonics die, the optical coupler narrowing in size from the edge of the silicon photonics die towards the waveguide,
wherein the optical coupler comprises a cantilever structure suspended in a channel formed in the silicon photonics die, the cantilever structure having a free end adjacent to the edge of the silicon photonics die and an anchored end disposed adjacent to the waveguide.
2. The silicon photonics module of claim 1 wherein the optical coupler is configured to couple the waveguide to an optical fiber that is mountable adjacent to the edge of the silicon photonics die.
3. The silicon photonics module of claim 2 wherein the waveguide has a smaller diameter than the optical fiber, and wherein the optical coupler narrows in size from the optical fiber to the waveguide to couple the optical fiber to the waveguide.
4. The silicon photonics module of claim 1 wherein the cantilever structure is tapered with the free end being wider than the anchored end.
5. The silicon photonics module of claim 1 wherein the cantilever structure is linked to the channel by a plurality of micro bridges disposed on either sides of the cantilever structure between the cantilever structure and the channel.
6. The silicon photonics module of claim 1 further comprising a stopper disposed at the edge of the silicon photonics die wherein the free end of the cantilever structure is recessed inwardly from the edge of the silicon photonics die to provide a gap between the stopper and the stopper and the free end of the cantilever structure to prevent damage from the optical fiber to the cantilever structure.
7. The silicon photonics module of claim 1 further comprising a groove disposed in the substrate to support the optical fiber, the groove being adjacent to edge of the silicon photonics and opposite to the free end of the cantilever structure.
8. The silicon photonics module of claim 7 wherein the groove is configured to align a center of the optical fiber to a center of the free end of the cantilever structure.
9. The silicon photonics module of claim 7 wherein the groove is configured to align centers of the optical fiber, the free and anchored ends of the cantilever structure, and the waveguide.
10. The silicon photonics module of claim 7 wherein the groove is V-shaped.
11. The silicon photonics module of claim 7 further comprising a cover disposed over the optical fiber and a bonding material disposed in the groove to secure the optical fiber in the groove.