Optical polarization

About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.

Orbital Angular Momentum Waves: Generation, Detection, and Emerging Applications

Abstract: Orbital angular momentum (OAM) has aroused a widespread interest in many fields, especially in telecommunications due to its potential for unleashing new capacity in the severely congested spectrum of commercial communication systems. Beams carrying OAM have a helical phase front and a field strength with a singularity along the axial center, which can be used for information transmission, imaging and particle manipulation. The number of orthogonal OAM modes in a single beam is theoretically infinite and each mode is an element of a complete orthogonal basis that can be employed for multiplexing different signals, thus greatly improving the spectrum efficiency. In this paper, we comprehensively summarize and compare the methods for generation and detection of optical OAM, radio OAM and acoustic OAM. Then, we represent the applications and technical challenges of OAM in communications, including free-space optical communications, optical fiber communications, radio communications and acoustic communications. To complete our survey, we also discuss the state of art of particle manipulation and target imaging with OAM beams.

Spontaneous Emission and Characteristics of Staggered InGaN Quantum-Well Light-Emitting Diodes

Abstract: A novel gain media based on staggered InGaN quantum wells (QWs) grown by metal-organic chemical vapor deposition was demonstrated as improved active region for visible light emitters. Fermi's golden rule indicates that InGaN QW with step-function like In content in the well leads to significantly improved radiative recombination rate and optical gain due to increased electron-hole wavefunction overlap, in comparison to that of conventional InGaN QW. Spontaneous emission spectra of both conventional and staggered InGaN QW were calculated based on energy dispersion and transition matrix element obtained by 6-band k middotp formalism for wurtzite semiconductor, taking into account valence-band-states mixing, strain effects, and polarization-induced electric fields. The calculated spectra for the staggered InGaN QW showed enhancement of radiative recombination rate, which is in good agreement with photoluminescence and cathodoluminescence measurements at emission wavelength regime of 425 and 500 nm. Experimental results of light-emitting diode (LED) structures utilizing staggered InGaN QW also show significant improvement in output power. Staggered InGaN QW allows polarization engineering leading to improved luminescence intensity and LED output power as a result of enhanced radiative recombination rate.

Polarization beam splitter using a binary blazed grating coupler.

Abstract: A novel polarization beam splitter using a two-layer grating coupler is proposed and demonstrated. It can directly couple the normally incident light from fiber into two separate waveguides according to their polarization states while splitting them. It realizes high coupling efficiency and a good extinction ratio by using binary blazed grating couplers. The coupling length is less than 14 microm. The extinction ratio is better than 20 dB for both polarizations over a 40 nm wavelength range, and the coupling efficiencies for the two layers are 58% and 50%.

1-Tb/s per channel coherent optical OFDM transmission with subwavelength bandwidth access

Abstract: 1-Tb/s per channel coherent optical OFDM transmission over 600-km SSMF fiber is demonstrated assisted with a recirculating frequency shifter. Record spectral efficiency and transmission reach is achieved at 1-Tb/s channel rate without Raman amplification.