Optical coupling between two nanobelts

Stimulus-Responsive Light Coupling and Modulation with Nanofiber Waveguide Junctions

“…At both wavelengths, the coupling efficiency is weakly dependent on gap separations <10 nm but there is a pronounced drop in light transfer from 10 to 50 nm similarly to other coupled optical systems such as belt WGs and microresonators. 25,34 The coupling of 450 nm light shows a decay of 1.6−1.8%/nm (ca. 0.10 dB/nm) that translates to a lower limit of 2 nm for the distance sensitivity of the device.…”

“…It is anticipated that the coupling between high-index contrast WGs would be strongly dependent on the separation between WGs, leading to significant optical modulation in the WG outputs when the WGs move apart by only a few nanometers. , To better understand light propagation and the decay of the optical field residing near the surface of dielectric WGs, we have fabricated nanofiber junctions and studied the power transfer occurring between coupled WGs as a function of coupling angle, gap separation, guided wavelength, and chemical stimulus. The approach involves cross-coupling nanofiber WGs with shallow coupling angles of ∼30° to produce small overlapping areas of <0.07 μm 2 .…”