As the detector is placed just in the evanescent field of the waveguide, the detector can only absorb a fraction of light intensity. This is very well desired as it allows the creation of a stationary wave within the waveguide, which requires that the reflected light intensity is comparable ...
A hollow waveguide (HWG) may generally be described as a light pipe made from dielectric materials or metals with a coaxial hollow core enabling radiation propagation by reflection at the inside wall24. If gaseous samples are injected into the hollow core, the HWG may simultaneously act as a m...
In the T-shape structures, the propagating light impinges on the i-region orthogonally from the Si waveguide, in this case the detector width is independent of the waveguide width. If we make the detector wider, we may expect that more light will be absorbed, so that we should see an inc...