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The relation between solar activity indices and earth atmosphere is studied in this current investigation using correlation as well as periodic analysis. The solar flare index and solar irradiance signal of India over different latitude values are considered in this study as solar activity indices and Earth atmospheric parameter respectively. To evaluate their relationship, last 33 years (1986 – 2018) of data is considered which covers solar cycle 22, 23 and almost the complete solar cycle 24. The solar irradiance of India over different considered geographical location has a positive correlation during solar cycle 23 and a negative correlation during solar cycle 24 with solar flare index. It has also been observed that the maximum correlation is exist between 5° - 10° latitude and 30° - 35° latitude data and the correlation has an increasing trend with higher latitude. The periodicity analysis of solar irradiance signal exhibits a similar type of inherent period with solar flare index as well as other activity indices. It can be suggested that the effect of the solar flare index is exists on the solar irradiance signal of India over different considered geographical location according to the current statistical investigation during solar cycle 22 – 24.

The data of soft x-ray solar flare activity for the interval 2008 to 2019 which covers the ascending, maximum, descending & part of minimum period of solar cycle 24 has been used for investigating the behavior of North-South (N-S) and East-West (E-W) asymmetries. Our statistical analysis revealed that the N-S asymmetry is a real phenomenon and that the solar cycle 24 shows southern predominance which is similar to the past solar cycle 21, 22 and 23. Hence a long-term periodic behavior could be inferred. The E-W asymmetry for the considered is found to be slight western dominated but the associated probability values indicates a statistically insignificant result.

In the present work, we have considered the daily signal of Solar Radio flux of 2800 Hz recorded daily by radio telescopes near Ottawa (operated during 14th February, 1947–31st May, 1991) and Penticton, British Columbia, Dominion Radio Astrophysical Observatory (operating since 1st June, 1991) during the period from 29th October, 1972 to 28th February, 2013. We have applied FIR nonlinear phase filter on the present discrete signal to denoise it. The memory of this denoising signal has been analyzed and it indicates short memory trend (anti-persistent) hidden in this spectrum. Then we have examined whether the signal possesses stationary properties. On the basis of autocorrelation analysis, quasi or partly stationary nature of the spectrum has been revealed.

I discuss our work to optimize of the properties of highly nonlinear Ge x As y Se 1-x-y chalcogenide glasses for all-optical signal processing.

Chalcogenide glasses, which contain the chalcogen elements S, Se and Te covalently bonded with network forming elements such as Ge, As, Sb, etc, possess a higher third order (Kerr) optical nonlinearity at telecommunications wavelengths than any other known glass. Their high linear index and low optical absorption also makes it practical to use them to fabricate nanowire waveguides. In particular the third order nonlinear response of these materials displays a pure refractive nonlinearity with negligible two-photon absorption and a complete absence of free carrier effects. As a result we have been able to demonstrate all optical signal processing of telecommunications signals at speeds up to 640Gb/s [1] and RF spectral analysis with ≈3THz bandwidth [2] using waveguides made from As 2 S 3 chalcogenide glass with nonlinear parameters up to ≈10,000W−1km−1. However, in order to reduce power requirements higher values of the nonlinear parameter are desirable. Here we describe our first results using a new waveguide material: Ge 11 As 22 Se 67 whose nonlinearity is about 4 times larger than As 2 S 3 [3] and which has allowed us to achieve nonlinear parameters in air-clad rib waveguides in excess of 26000W−1km−1. Rib waveguides were fabricated by dry etching 340nm deep into 680nm thick glass films deposited by thermal evaporation onto an oxidized silicon wafer. Waveguides 3µm and 4µm wide were used in these experiments and these had nonlinear parameters (γ=2πn 2 /A eff γ) of 33000W−1km−1 and 26000W−1km−1 respectively - record values for a glass waveguide. This enhanced nonlinear response along with dispersion control leads to strong effects such as supercontinuum generation (Fig. 1(a)) and broad-band four wave mixing with large gain (Fig. 1(b)) using pulses with peak powers of 10–30W. The nonlinear response is also sufficient to allow nonlinear processing using CW powers in the 100mW range. This talk will describe the properties of Ge 11 As 22 Se 67 waveguides and their nonlinear properties at telecommunications wavelengths.

Chalcogenide glasses are an important class or amorphous materials with applications that include phase-change optical memories, solar cells, and optical waveguides. Particularly interesting for optical applications is their good transparency in the mid-infrared combined with their high linear and nonlinear refractive indices. This last property has motivated interest in the use of chalcogenide waveguides for all-optical processing of high-speed telecommunications signals [1].

This research focuses on several aspects of chalcogenide all-optical processors. This study has chosen glasses in the Ge-As-Se system with the aim of optimising glass composition to obtain low loss, high nonlinearity and glass stability, whilst complementary efforts are focussed on the production, optimisation and application of chalcogenide waveguide devices to all-optical of high-speed telecommunication signals. Devices have been characterised in realistic telecommunications conditions with the eventual aim being to validate performance at rates up to 640 Gb/s.

GexAsySe100-x-y glasses with 0les xles40 and 12lesyles40 have been characterized for properties of bulk material as well as thermally deposited films. The effect of phase separation on film properties is studied.

The optical and structural properties of Ge-As-Se glasses have been studied using Raman, UV-Vis-IR, Z-scan and DSC techniques, and the effect of composition on structural transition, optical band gap and nonlinearity is described.

Chalcogenide glasses, which contain S, Se or Te atoms combined with network forming elements such as Ge, As, Sb have the largest third order optical nonlinearity of any inorganic glass. As a result they are attractive candidates for fibre and waveguide devices for all-optical signal processing in the telecommunications bands. In this talk I will review our recent progress in all-optical devices such as regenerators, wavelength converters and other devices in chalcogenide glasses.

Optical properties of chalcogenide glasses, GexAsySe100-x-y (33les x les39 and 12les y les16) were studied by using Raman, UV-vis-IR and PDS spectroscopic techniques, and the relationships between structure, composition and optical property were discussed.