We show that the rate at which light tunnels between neighboring multimode waveguides can be drastically increased or reduced by the presence of small longitudinal periodic modulations of the waveguide properties that stimulate resonant conversion between the eigenmodes of each waveguide. Such a conversion, available only in multimode guiding structures, leads to periodic power transfer into hi...

We propose a multimode retina integrating image sensing, normalization, smoothing, differentiation and visual feature extraction by incorporating: 1) a histogram equalization function onto the sensor focal plane, which normalizes the image signal at the same dynamic range under different illumination conditions and results a constant signal amplitude facilitating the post processing; 2) a capac...

We report on an ultralow-threshold Raman laser based on a CaF2 whispering-gallery-mode resonator. The laser is demonstrated to have a conversion efficiency above 60%. The observed low lasing threshold is made possible by the ultrahigh optical quality factor of the cavity, which is on the order of Q=1010. The laser is fibercompatible and is fabricated with a very simple technique. We also demons...

The article presents a fiber-optic sensor based on singlemode-multimode-singlemode (SMS) structure for simultaneous measurement of strain and curvature. It is shown that the demodulation curvature can be realized using Fourier analysis recorded interference oscillations. Keywords: optical fiber sensors, intermode interference, single mode-multimode-single mode, stretching, bending.

We report on the first (to our knowledge) experimental observation of higher-order modes guided by soliton-induced waveguides in nematic liquid crystals. We find that the nematicon waveguides operate in a bounded power region specific to each guided mode. Below this region, the guided beams diffract; above this region, the mode mixing and coupling give rise to an unstable output.

The combined capabilities of both a nonplanar design and nonconventional carrier injection mechanisms are subject to recent scientific investigations to overcome the limitations of silicon metal oxide semiconductor field effect transistors. In this Letter, we present a multimode field effect transistors device using silicon nanowires that feature an axial n-type/intrinsic doping junction. A het...

In this paper the coherent states and q-symmetric states for gl q (n)-covariant multimode oscillator system are investigated.

Ah.WoCl-A m u l t i o d e fih+matched arrayed waveguide grating-based demultiplexer has befn demonstrated. In thb design. multimode waveguides have been used 85 m y clements. The device, which can he used in short-dbtance communications, has been realized using low-cos1 polymer planar waveguide technology. Three wavclenglh ehanncls were SUCC~S. fully separsled. The average fiber-to-fiber inserl...

A novel scheme to achieve mode-locking of a multimode laser is demonstrated. Traditional methods to produce ultrashort laser pulses are based on modulating the cavity gain or losses at the cavity roundtrip frequency, favoring the pulsed emission. Here, we rather directly act on the phases of the modes, resulting in constructive interference for the appropriated phase relationship. This was perf...

We describe novel fiber Raman lasers pumped directly by spectrally combined high power multimode laser diodes at ∼975 nm and emitting at ∼1019 nm. With a commercial multimode graded-index fiber, we reached 20 W of laser output power with a record slope efficiency of 80%. With an in-house double-clad fiber, the beam quality improved to M = 1.9, albeit with lower output power and slope efficiency...