Sagnac loop mirror based laser cavity on silicon photonics platform
View Patent ↗We have demonstrated a novel Sagnac loop and micro-ring based laser cavity which is simple and reliable, with accurately controlled reflectivity and negligible excess loss. The resonant wavelength of a 2 μm radius micro-ring is shown to be lithographically controlled to a standard deviation of 3.6 nm. Both C- and O-Band lasers based on Sagnac loop mirror and micro-ring cavity have been demonstrated. The lasers are shown to be able to be modulated at 40 Gb/s.
1. An optical cavity, comprising:
a single optical port configured to provide an optical output beam;
a first mirror element comprising a submicron silicon waveguide, said first mirror element having a first transmittance and a first reflectivity, said first mirror element forming a first optical reflector situated at a first end of the optical cavity, said first mirror element in optical communication with said single optical port;
a second mirror element having a second transmittance and a second reflectivity, said second mirror element forming a second optical reflector situated at a second end of the optical cavity;
at least one of said first mirror element and said second mirror element is a Sagnac loop mirror; and
situated in serial optical communication between said first mirror element and said second mirror element:
a filter element configured to pass an optical beam having a selected optical wavelength therethrough; and
a gain cavity configured to contain therein an optical gain medium.
2. The optical cavity of claim 1 , wherein said first mirror element is a broadband reflector.
3. The optical cavity of claim 1 , wherein said first mirror element has a reflectivity that increases as the selected wavelength is increased.
4. The optical cavity of claim 1 , wherein said first mirror element has a variable reflectivity.
5. The optical cavity of claim 1 , wherein said filter element is a micro-ring based filter.
6. The optical cavity of claim 1 , wherein said filter element is a tunable filter.
7. The optical cavity of claim 1 , wherein said filter element is a thermally tunable filter.
8. The optical cavity of claim 1 , wherein said filter element has multiple pass bands.
9. The optical cavity of claim 1 , wherein said second mirror has a reflectivity defined by a facet.
10. The optical cavity of claim 1 , wherein said selected optical wavelength is a wavelength situated within a wavelength range used in telecommunication.
11. The optical cavity of claim 10 , wherein said selected optical wavelength is a wavelength situated within the O-Band.
12. The optical cavity of claim 10 , wherein said selected optical wavelength is a wavelength situated within the C-Band.
13. The optical cavity of claim 10 , wherein said selected optical wavelength is a wavelength situated within a band selected from the e-Band, the S-Band, the L-Band and the U-Band.
14. The optical cavity of claim 1 , wherein at least one of said first mirror element and said second mirror element is disposed on a silicon substrate, and said gain cavity contains an optical gain medium comprising a III/V semiconductor compound.
15. The optical cavity of claim 14 , wherein said optical gain medium is optically coupled to said optical cavity via at least one of a butt-coupler, a taper, an inverse taper, a lens, and a lens array.
16. The optical cavity of claim 1 , wherein said optical cavity is configured to be operated without cooling.
17. The optical cavity of claim 1 , wherein said optical cavity is configured to be operated without hermetic sealing.
18. The optical cavity of claim 1 , wherein said facet comprises an optical coating.
19. The optical cavity of claim 1 , wherein said optical output beam comprises a single optical wavelength of interest.
20. The optical cavity of claim 1 , wherein said optical output beam comprises a plurality of optical wavelengths of interest.
21. The optical cavity of claim 1 , wherein said optical output beam comprises a narrow linewidth optical output beam.