Asymmetric cross-polarization coupling between microresonator whispering-gallery modes

Review of effects involving coresonant whispering-gallery modes of orthogonal polarization

“…Observation of output polarized orthogonally to the input, whose amplitude is proportional to t21, allows us to find the nonreciprocity in CPC, i.e., the ratio of amplitudes b = t21/ t12 being different from unity. 10 Reasonable agreement between experimental and calculated values of b is found and will be discussed in another paper in this session (12447-131).…”

“…[1][2][3][4][5][6] We have studied coupled-mode-induced transparency (CMIT) and Autler-Townes splitting (ATS) with pulse delay, and coupled-mode-induced attenuation (CMIA) with pulse advancement or delay, when there is coupling between two coresonant modes with very different quality factors (Qs) and orthogonal polarizations. [7][8][9][10] These behaviors may be exploited for numerous applications such as signal processing and optical sensing. [11][12][13] In that work, [7][8][9][10] the modes were coupled by cross-polarization coupling (CPC), resulting from the spin-orbit interaction of light in a microresonator's WGMs.…”

“…[7][8][9][10] These behaviors may be exploited for numerous applications such as signal processing and optical sensing. [11][12][13] In that work, [7][8][9][10] the modes were coupled by cross-polarization coupling (CPC), resulting from the spin-orbit interaction of light in a microresonator's WGMs. Without CPC, we have also found behavior qualitatively the same, namely modesuperposition-induced transparency (MSIT) with pulse delay and mode-superposition-induced attenuation (MSIA) with pulse advancement or delay.…”

Nonreciprocal cross-polarization coupling in whispering-gallery microresonators

“…The fact that throughput on mode 2 is observed is evidence for the existence of CPC, and knowing b and Tc allows us to determine both t21 and t12, demonstrating the nonreciprocity of CPC. 16 Tc and b can be calculated for a representative set of mode numbers that give values of Tc and b similar to those determined experimentally. 13 To understand why b  1, i.e., CPC is nonreciprocal, first consider another type of coupling, that between a tapered-fiber mode and a microresonator WGM.…”

“…13 We have previously described a method for experimentally determining the CPC strengths of TE to TM coupling and TM to TE coupling in a hollow bottle resonator (HBR). 16 Here we give an explanation of why the cross-polarization coupling is nonreciprocal.…”