We used ultrafast laser inscription to fabricate three-dimensional integrated optical transitions that efficiently couple light from a multimode waveguide to a two-dimensional array of single mode waveguides and back. Although the entire device has an average insertion loss of 5.7 dB at 1539 nm, only ≈0.7 dB is due to mode coupling losses. Based on an analysis which is presented in the paper, w...

A refractive index (RI) sensor based on a novel fiber structure that consists of a single-mode-multimode-single-mode (SMS) fiber structure followed by a fiber Bragg grating was demonstrated. The multimode fiber in the SMS structure excites cladding modes within output single-mode fiber (SMF) and recouple the reflected cladding Bragg wavelength to the input SMF core. By measuring the relative Br...

A vast majority of the installed fiber connections in the enterprise data centers consists of veryshort-reach legacy fiber cable connections, with 62.5 μm fiber core diameter. This multimode fiber, originally installed for Fiber Optic Distributed Data Interface (FDDI) applications, is capable of handling 1-2 Gb/s. It becomes a problem at 10 Gb/s, where differential mode dispersion leads into di...

Deploying a PON using multimode fiber in the access network is viewed as a costeffective solution. However, a multimode fiber link exhibits a time-dispersive nature. To cope with this problem, an OFDM transmission method is used. In this work, a comparison study on several duplexing methods for this system was performed to decide upon the recommended method for the system. The choices that were...

The self-imaging property of a homogeneous multi-moded planar optical waveguide has been applied in the design optical couplers based on multimode Interference (MMI). Based on this design, the optical wavelength and dimensions tolerance for MMI-3dB couplers are investigated analytically. They are shown to be inversely proportional to the multimode section width. Among Symmetrical, paired, and g...

We study the mechanical properties of a broad class of multimode and polarization light patterns, resulting from the interference and superposition of waves in helical modes. General local and global properties of energy and angular momentum (AM) are identified, in order to define the conditions to optimize the AM with increasing beam complexity. We show the possibility to engineer independentl...

Multimode fibers (MMFs) offer a cost-effective connection solution for small and medium length networks. However, data rates through multimode fibers are traditionally limited by modal dispersion. Signal processing and Multiple-Input MultipleOutput (MIMO) have been shown to be effective at combating these limitations, but device design for the specific purpose of MIMO in MMFs is still an open i...

We review some recent experiments based upon multimode two-photon interference of photon pairs created by spontaneous parametric downconversion. The new element provided by these experiments is the inclusion of the transverse spatial profiles of the pump, signal and idler fields. We discuss multimode Hong-Ou-Mandel interference, and show that the transverse profile of the pump beam can be manip...

In this paper, we propose a limited feedback transmission based on precoding mechanism for multiple-input multiple-output (MIMO) systems, referred as to supermode transmission. With a fixed data-rate, it allows different degree-of-freedom (DoF) depending on the current channel state information (CSI) and different transmission scheme with the same DoF. Through numerical examples, we show that t...

We have developed a multimode dermoscope (SkinSpectTM) capable of illuminating human skin samples in-vivo with spectrally-programmable linearly-polarized light at 33 wavelengths between 468nm and 857 nm. Diffusely reflected photons are separated into collinear and cross-polarized image paths and images captured for each illumination wavelength. In vivo human skin nevi (N = 20) were evaluated wi...