VCSEL on silicon integrated circuit
View Patent ↗Vertical Cavity Surface Emitting Laser (VCSEL) on silicon substrate. One embodiment described herein includes an apparatus with functionality for communicating optical signals on a silicon integrated circuit chip. The apparatus includes a silicon based integrated circuit chip die. An optical waveguide is formed at the silicon based integrated circuit chip die. A vertical cavity surface emitting laser (VCSEL) is mechanically coupled to the silicon base integrated circuit chip die and optically coupled to the optical waveguide.
1. A method of testing an optical communication system, wherein the optical communication system comprises a VCSEL coupled mechanically to a silicon substrate, and coupled optically to an optical waveguide at the silicon substrate, the method comprising:
applying a signal to the VCSEL to cause the VCSEL to lase into the optical waveguide, wherein the VCSEL is fabricated such that emissions from a first surface of the VCSEL are related to emissions from a second surface of the VCSEL;
measuring the emissions from the first surface of the VCSEL;
measuring an electrical signal caused by an emission from the second surface of the VCSEL;
comparing the emissions from the first surface of the VCSEL to the electrical signal caused by the emission from the second surface of the VCSEL; and
determining from the comparison if the optical communication system is functioning properly.
2. The method of claim 1 , wherein the method is performed on individual die at a wafer scale, such that testing is performed prior to cleaving the individual die.
3. The method of claim 1 , wherein measuring an electrical signal caused by an emission from the second surface of the VCSEL is performed using a photodiode optically coupled to the optical waveguide at the silicon substrate, and wherein the photodiode is implemented as part of a receiver circuit for receiving optical communication signals.
4. The method of claim 1 , wherein measuring an electrical signal caused by an emission from the second surface of the VCSEL is performed using a photodiode optically coupled to the optical waveguide at the silicon substrate, and wherein the photodiode is implemented as part of a testing circuit.
5. The method of claim 1 , wherein applying a signal to the VCSEL comprises modulating the VCSEL.
6. The method of claim 1 , wherein the VCSEL is mechanically coupled to the silicon substrate using VCSEL flip-chip bonding to silicon using self aligning contacts.
7. The method of claim 1 , wherein the VCSEL is mechanically coupled to the silicon substrate using fiducial marks on the VCSEL and on the silicon substrate for aligning the VCSEL to the silicon substrate.
8. The method of claim 1 , wherein the VCSEL is fabricated using GaAs.
9. The method of claim 1 , wherein the VCSEL is a long wavelength VCSEL.
10. The method of claim 1 , wherein coupling optics are coupled to the optical waveguide.
11. The method of claim 1 , wherein the optical waveguide comprises a SiO2 structure.
12. The method of claim 1 , wherein a lens is coupled to the VCSEL.
13. The method of claim 1 , wherein a lens is coupled to the optical waveguide.
14. The method of claim 1 , wherein optical sensing circuitry is fabricated on the silicon substrate and is optically coupled to the optical waveguide.
15. The method of claim 1 , wherein the VCSEL is configured to couple to an external optical waveguide in addition to the optical waveguide formed at the silicon substrate.
16. The method of claim 1 , wherein an optical coupler is coupled to VCSEL so as to allow different chips or different systems to be interconnected optically.