Waveguides multimode

When the gain medium incorporating nanoparticles is deposited onto glass substrates defining a planar asymmetric slab waveguide, multimode laser emission can appear without the need of the presence of any resonant substructure. 

Fig. 2. Waveguide stmcture showiag the total internal reflection of light. The diameter, is 50 p.m for a standard multimode system, 62.5 p.m for a large...

If the core only corresponds to one speckle spot the fibre is monomode. Otherwise the waveguide is multimode. This back to the envelop calculation intuitively shows the origin of the mode number. Note that N is wavelength dependent the larger the wavelength, the lower the number of mode. 

Perhaps the most effective demonstration of the advantages of evanescent wave interrogation is provided by the optical biosensor platform depicted in Figure 5. The platform consists of a multimode slab waveguide on the upper surface of which antibodies have been immobilised. 

The absorption-based platforms described previously employed evanescent wave interrogation of a thin sensing layer coated onto a planar waveguide. A sensitivity enhancement strategy for optical absorption-based sensors based on planar, multimode waveguides was developed recently by us18. The objective was to apply this theory to the development of low-cost, robust and potentially mass-producible sensor platforms and the following section outlines the assumptions and predictions of this theoretical model. 

Skivesen, N. Horvath, R. Pedersen, H. C., Multimode reverse symmetry waveguide sensor for broad range refractometry, Opt. Lett. 2003, 28, 2473 2475... 

Fig. 9.17 Silicon waveguide ring resonators employing (a) a directional coupler (DC), and (b) a multimode interference (MMI) coupler, as viewed from above using a scanning electron micro scope...

An optical MNF is a waveguide that transmits light. Generally, an MNF is a multimode waveguide. In this chapter, we primarily consider single mode MNFs, which support the fundamental mode only. The diameter of a single mode MNF is... 

Fig. 18.14 LC ARROW analysis based on radiation pressure, (a) Time dependent microbead position for extraction of waveguide loss (symbols data, line fit) (b) lateral mode profile determination (bars histogram of measured lateral particle position, line, multimode profile calculated with commercial mode solver...

Multilayer Langmuir-Blodgett films doped with a cyanine dye have been deposited on the surface of a quartz multimode optical fiber and the fluorescence properties investigated. 49 The fluorescence intensity of the films was found to be a periodic function of the number of layers due to the waveguide properties of the films. 

The 2D MMl structures are multimode waveguides in both the transverse directions. The modal interference along the propagation causes self and multiple images in the whole transverse plane. Thus, to have Nx x Ny images we need to have... 

Multimode Fiber—An optical waveguide in which light travels in multiple modes. Typical core/cladding size (measured in micrometers) is 62.5/125. 

In this manner it is possible to construct a very simple refractometer. It should be mentioned that very sensitive devices using the multimode freestanding waveguide can be achieved by monitoring only the intensity of the highest-order mode. Here detection limits down to 3 x 10-5 hve been demonstrated [27]. 

Figure 3.5 Reactor for batchwise organic synthesis. 1. Reaction vessel 2, top flange 3, cold finger 4, pressure meter 5, magnetron 6, forward/reverse power meters 7, magnetron power supply 8, magnetic stirrer 9, computer 10, optic fiber thermometer 11, load matching device 12, waveguide 13, multimodal cavity (applicator). (From Ref. 712, reproduced with permission.)...

Figure 4.15 Illustration of the constructive and destructive interference pattern in a Mach-Zehnder waveguide modulator. Only if the outgoing waveguide is single mode, the resulting antisymmetric mode will be completely radiated into the substrate. A multimode waveguide cannot be used for an efficient Mach-Zehnder modulator...

---