We present experimental results for combined mode-multiplexed and wavelength multiplexed transmission over conventional graded-index multimode fibers. We use mode-selective photonic lanterns as mode couplers to precisely excite a subset of the modes of the multimode fiber and additionally to compensate for the differential group delay between the excited modes. Spatial mode filters are added to...

Genetic algorithm is adopted in this paper as a technique for searching suitable subcarriers in subcarrier multiplexing (SCM) on multimode fiber (MF). Six suitable subcarriers, which are not located at any nulls in the frequency response of multimode fiber are determined. It is shown that these six subcarriers are at the peak of the passbands of the multimode fiber. These subcarriers are then u...

It is shown that it is possible to couple a laser beam and its frequency-doubled daughter into a multimode optical fiber through the four-wave mixing nonlinear process and generate a new wavelength. The frequency-doubled daughter can be generated in an external crystal with a large second order nonlinearity. It is argued that while this possibility is within the design parameter range of conven...

An optimal design method for a low broadband silica-on-silicon Y branc is considered. A multimode waveguide section, which was used earlier to reduce the excess loss, is designed optimally when the light distribution at the end of the multimode waveguide section is matched to the profile of the symmetric supermode for the structure of the two branching waveguides. An optimization method that co...

We demonstrate the feasibility of the process for fabricating a single-mode waveguide and a large-core multimode waveguide aligned vertically on the same substrate. Using this process, we propose and demonstrate a filter that drops optical signal propagating in a single-mode waveguide to a multimode waveguide in the specific wavelength interval by a long-period grating. We use perfluorocyclobut...

Abstract Speckle metrology is a powerful tool in the measurement of wavelength and spectra. Recently, speckle produced by multiple reflections inside an integrating sphere has been proposed showed high performance. However, to our knowledge, complete characterisation sensitivity that geometry not performed date. In this work, we derive general model predicting variation pattern as result generi...

The purpose of this paper is to present a fiberoptic vibration sensor based on the monitoring of the mode distribution in a multimode optical fiber. Detection of vibrations and their parameters is possible through observation of the output speckle pattern from the multimode optical fiber. A working experimental model has been built in which all used components are widely available and cheap: a ...

Multimode laser operation is usually characterized by high output power, yet its beam quality is inferior to that of a laser with single TEM00 mode operation. Here we present an efficient approach for improving the beam quality of multimode laser resonators. The approach is based on splitting the intra-cavity multimode beam into an array of smaller beams, each with a high quality beam distribut...

We experimentally demonstrate that Kerr spatial self-cleaning of a pulsed beam can be obtained in an amplifying multimode optical fiber. An input peak power of 500 W only was sufficient to produce a quasi-single-mode emission from the double-clad ytterbium doped multimode fiber (YMMF) with non-parabolic refractive index profile. We compare the self-cleaning behavior observed in the same fiber w...

We investigate the point spread function of a multimode fiber. The distortion of the focal spot created on the fiber output facet is studied for a variety of the parameters. We develop a theoretical model of wavefront shaping through a multimode fiber and use it to confirm our experimental results and analyze the nature of the focal distortions. We show that aberration-free imaging with a large...