Optical ring resonators

Optical ring resonators consist of a waveguide in a closed loop coupled to one or more input/output (or bus) waveguides. When light of the appropriate wavelength is coupled to the loop by the input waveguide, it builds up in intensity over multiple round-trips due to constructive interference. It can then be picked up by a detector waveguide. Since only some wavelengths resonate within the loop, it functions as a filter. Recently, two sets of coupled waveguides have been used to form an add/drop optical filter.^[1] The add/drop optical filter is then used to analyze vector solitons, which can be either right-handed or left-handed circularly polarized, thus forming two distinct optoelectronic (soliton) spin states.^[2]

Research

Numerous groups do related research in optical computing, filters, and photonic logic based on ring resonators, most prominently at Cornell University, University of Maryland, College Park, University of Southern California, Politecnico di Milano, King Mongkut's Institute of Technology Ladkrabang and the Hertz Institute (German only).

Applications

Researchers at Cornell University have been successful in using a micrometer scale ring resonator for switching light on and off at Gigahertz repetition rates.^[3] Other applications such as all optical switching, electro-optical switching, wavelength conversion, reconfigurable optical delay lines^[4] and filtering have been demonstrated using ring resonators.^{[citation needed]} They are especially useful for exotic nonlinear optics experiments, and may eventually lead to photonic logic. At least one company sells filters based on optical ring resonators.^{[citation needed]}

See also

• Resonator
• Ring laser
• Figure-8 laser
• Semiconductor ring laser
• Ring laser gyroscope
• Filter (optics)
• Optical switch

References

1. ^ Phongsanam, P.; Teeka, C.; Mitatha, S.; Yupapin, P. P. (2011). "Simultaneous All-Optical Logic AND and OR Gates based on Photonic Circuits". Optics and Photonics Letters 4 (1): 17–24. doi:10.1142/S1793528811000147. 
2. ^ Mitatha, S.; Glomeglom, S.; Teeka, C.; Ali, J.; Yupapin, P. P. (2011). "Soliton Spin and Wave-Particle Duality". Optics and Photonics Letters 4 (2): 1–11. doi:10.1142/S1793528811000202. 
3. ^ Nature May 2005
4. ^ http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-16-12-8395