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Recent advances in mode converters for a mode division multiplex transmission system

Memon A. K., Chen K. X.

Opto-Electronics Review

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2021

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Vol. 29, No. 1

13--32

EN

Adopting mode division multiplex (MDM) technology as the next frontier for optical fiber communication and on-chip optical interconnection systems is becoming very promising because of those remarkable experimental results based on MDM technology to enhance capacity of optical transmission and, hence, making MDM technology an attractive research field. Consequently, in recent years the large number of new optical devices used to control modes, for example, mode converters, mode filters, mode (de)multiplexers, and mode-selective switches, have been developed for MDM applications. This paper presents a review on the recent advances on mode converters, a key component usually used to convert a fundamental mode into a selected high-order mode, and vice versa, at the transmitting and receiving ends in the MDM transmission system. This review focuses on the mode converters based on planar light wave circuit (PLC) technology and various PLC-based mode converters applied to the above two systems and realized with different materials, structures, and technologies. The basic principles and performances of these mode converters are summarized.

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Planarne sprzęgacze siatkowe do zastosowań w spektroskopii pola zanikającego

Karasiński P.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 6

94-96

PL

Praca dotyczy zastosowania wejściowego sprzęgacza siatkowego w spektroskopii pola zanikającego. Sprzęgacz siatkowy o okresie Λ = 1000 nm był wytworzony na światłowodzie planarnym SiO₂:TiO₂ z zastosowaniem metody zol-żel i odciskania wzoru siatki. Praca przedstawia wyniki analizy teoretycznej struktury sensorowej i wyniki badań eksperymentalnych wytworzonych sprzęgaczy siatkowych.

EN

The work involves the applications of input grating coupler in evanescent field spectroscopy. Surface relief grating with period Λ = 1000nm on planar SiO₂:TiO₂ waveguides were fabricated by combination of a dip-coating method (sol-gel) with an embossing technique. The work presents the results of theoretical analysis of the sensor structure and the results of experimental research on the produced grating couplers.

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Photonic crystals: a novel class of functional materials

Modinos A., Stefanou N.

Materials Science Poland

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2005

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Vol. 23, No. 4

877--881

EN

Photonic crystals are inhomogeneous materials whose dielectric properties vary periodically in space on a macroscopic scale. These materials have novel and interesting properties concerning both basic physics and technological applications. After a brief description of the main properties of photonic crystals, we present some specific applications related to wave guiding and Anderson localization of light due to stacking faults in these crystals.

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Upconversion of He-Ne Laser Light in Xanthene Dye-Doped Polymer Waveguides

Samoc A., Samoc M., Luther-Davies B.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 2-3

345-358

EN

We report on generation of yellow light emission (peak intensity at 577 nm) from a low power red He-Ne laser beam (1mW, 632.8 nm) propagating in dye-doped planar polymer waveguides. Upconversion of He-Ne light (higher energy photons created by lower energy photons) was observed in planar slab waveguides made of poly(N-vinylpyrrolidone) (PVP) doped with Phloxine B. The films viewed from the side show a characteristic streak of yellow light. Monitoring it with a CCD camera we find that logarithm of intensity decays linearly with propagation distance, the slope giving the total loss factor. The loss factor at 632.8 nm depended linearly on the dye concentration providing the decadic absorption coefficient of 54 cm-1 for neat Phloxine B. The upconverted yellow luminescence can be regarded as a convenient indicator of waveguide losses. Monitoring fluorescence instead of the scattered guided light provides much more noise-free waveguide loss data. We measured spectral and temporal response of the upconverted fluorescence as well as the dependence of luminescence on the intensity of the He-Ne beam to learn about the nature of the observed emission. The spectra excited with He-Ne laser as well as with 488 nm from cw Ar ion laser were similar. The lifetime of the luminescence in films of Phloxine B and Ethyl Eosin in PVP was of the order of 1 ms. The intensity of upconverted emission was found to vary linearly with the input intensity.We postulate that the mechanism of upconversion in the materials involves the first triplet state of the dye and generation of delayed fluorescence by these states.