Erbium Doped Fiber Lasers for Long Distance Communication Using Network of Fiber Optics
Thalangunam Krishnaswamy Subramaniam
Issue:
Volume 3, Issue 3, June 2015
Pages:
34-37
Received:
21 July 2015
Accepted:
28 July 2015
Published:
11 August 2015
Abstract: A fiber doped with erbium laser is used in long distance communication over networks of fiber optics. Especially, in under water communication links where optical signals can be amplified by joining erbium-doped fiber at appropriate locations in the network of the fiber. Thus, a signal, when optically transmitted will get amplified and this will be useful when the signal travels between continents. There is no need for converting an optical signal into an electrical signal, amplified and then reintroduced into the fiber for transmission. The latest research trend is to produce ultra-short pulse widths of the order of 100fs and with a pulse repetition rate of the order of 10GHz. Here I have used an Er3+ doped silica fiber for optical pumping λ=0.98µm or λ=1.48µm wavelength using radiation from a diode laser [Fig. 1]. A coupler was used to select the wavelength, which permits this light to reach the optical fiber transmission system, without disturbing the signal. The optical fiber is spliced into the transmission lines, which acts as an optical isolator. This fiber is constantly pumped by the diode laser. When the pulses pass through the system, they get amplified, while the pump light is reduced.
Abstract: A fiber doped with erbium laser is used in long distance communication over networks of fiber optics. Especially, in under water communication links where optical signals can be amplified by joining erbium-doped fiber at appropriate locations in the network of the fiber. Thus, a signal, when optically transmitted will get amplified and this will be...
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LED Light Spectrum Affects the Photosynthetic Performance of Houttuynia Cordata Seedlings
Zhaoqing Wang,
Jingyun Tian,
Bo Yu,
Liyan Yang,
Yi Sun
Issue:
Volume 3, Issue 3, June 2015
Pages:
38-42
Received:
21 July 2015
Accepted:
28 July 2015
Published:
11 August 2015
Abstract: We investigated the effects of light-emitting diodes (LED) with various light spectrum (white, red, yellow, green and blue) on photosynthesis of Houttuynia cordata seedlings. The seedlings were either cultivated under florescent lamp or under various LED lights. The leaves were collected and chlorophyll fluorescence parameters, the contents of chlorophyll, soluble sugar and relative water were measured, chloroplasts were observed as well. The results showed chlorophyll fluorescence parameters as Fv/Fm, qP and qY values were the highest under blue LED light and the values were the lowest under green LED light. Red LED light resulted in the enhanced chlorophyll content compared with the other LED lights, and the chl a/chl b ratio did not change significantly among LED treatments. The soluble sugar content was not significantly different among the treatments. The red LED increased relative water content and the green LED decreased the water content. Observation of chloroplasts in the leaves of Houttuynia cordata seedlings showed chloroplast number and distribution were altered by various light spectrum where chloroplasts were smaller under blue LED, and appeared to be more scattered under red LED. Our results indicated that photosynthesis of Houttuynia cordata seedlings respond differently to various light spectrum emitted by florescent lamp and LED
Abstract: We investigated the effects of light-emitting diodes (LED) with various light spectrum (white, red, yellow, green and blue) on photosynthesis of Houttuynia cordata seedlings. The seedlings were either cultivated under florescent lamp or under various LED lights. The leaves were collected and chlorophyll fluorescence parameters, the contents of chlo...
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