Gain enhancement in L-band loop EDFA through C-band signal injection

2005 ◽  
Vol 17 (7) ◽  
pp. 1402-1404 ◽  
Author(s):  
A. Altuncu ◽  
A. Basgumus
Keyword(s):  
Gain Enhancement ◽  
Signal Injection ◽  
L Band ◽  
Band Signal

Long-wavelength EDFA gain enhancement through 1550 nm band signal injection

2000 ◽  
Vol 176 (1-3) ◽  
pp. 125-129 ◽  
Author(s):  
M.A Mahdi ◽  
F.R Mahamd Adikan ◽  
P Poopalan ◽  
S Selvakennedy ◽  
W.Y Chan ◽  
...  
Keyword(s):  
Long Wavelength ◽  
Gain Enhancement ◽  
Signal Injection ◽  
Band Signal

scholarly journals Simultaneous observations of ESF irregularities over Indian region using radar and GPS

2008 ◽  
Vol 26 (11) ◽  
pp. 3197-3213 ◽  
Author(s):  
S. Sripathi ◽  
S. Bose ◽  
A. K. Patra ◽  
T. K. Pant ◽  
B. Kakad ◽  
...  
Keyword(s):  
Spectral Width ◽  
Indian Region ◽  
Activity Period ◽  
Small Scale ◽  
Electron Content ◽  
Total Electron ◽  
Radar Echoes ◽  
Mst Radar ◽  
L Band ◽  
Band Signal

Abstract. In this paper, we present simultaneous observations of temporal and spatial variability of total electron content (TEC) and GPS amplitude scintillations on L1 frequency (1.575 GHz) during the time of equatorial spread F (ESF) while the MST radar (53 MHz) located at Gadanki (13.5° N, 79.2° E, Dip latitude 6.3° N), a low latitude station, made simultaneous observations. In particular, the latitudinal and longitudinal extent of TEC and L-band scintillations was studied in the Indian region for different types of ESF structures observed using the MST radar during the low solar activity period of 2004 and 2005. Simultaneous radar and GPS observations during severe ESF events in the pre-midnight hour reveal that significant GPS L band scintillations, depletions in TEC, and the double derivative of the TEC index (DROTI), which is a measure of fluctuations in TEC, obtained at low latitudes coincide with the appearance of radar echoes at Gadanki. As expected, when the irregularities reach higher altitudes as seen in the radar map during pre-midnight periods, strong scintillations on an L-band signal are observed at higher latitudes. Conversely, when radar echoes are confined to only lower altitudes, weak scintillations are found and their latitudinal extent is small. During magnetically quiet periods, we have recorded plume type radar echoes during a post-midnight period that is devoid of L-band scintillations. Using spectral slopes and cross-correlation index of the VHF scintillation observations, we suggest that these irregularities could be "dead" or "fossil" bubbles which are just drifting in from west. This scenario is consistent with the observations where suppression of pre-reversal enhancement (PRE) in the eastward electric field is indicated by ionosonde observations of the height of equatorial F layer and also occurrence of low spectral width in the radar observations relative to pre-midnight period. However, absence of L-band scintillations during post-midnight event, when radar observed plume like structures and scintillations were recorded on VHF band, raises questions about the process of evolution of the irregularities. A possible explanation is that whereas small scale (~3 m) irregularities are generated through secondary waves that grow on the walls of km scale size irregularities, in this case evolution of the Rayleigh-Taylor instability itself did not extend to irregularities of scale sizes of a few hundred meters that produce scintillation on a L-band signal.

Gain and Noise Figure Performances of L–Band EDFA with an Injection of C–Band ASE

2012 ◽  
Author(s):  
Sulaiman Wadi Harun ◽  
T. Subramaniam ◽  
Nizam Tamchek ◽  
Harith Ahmad
Keyword(s):  
Spontaneous Emission ◽  
Noise Figure ◽  
Amplified Spontaneous Emission ◽  
Fiber Amplifier ◽  
Optical Amplifier ◽  
Injection Technique ◽  
Erbium Doped Fiber Amplifier ◽  
Gain Enhancement ◽  
Gain Clamping ◽  
L Band

Kesan suntikan pancaran spontan terkuat (ASE) jalur–C terhadap prestasi jalur–L penguat gentian terdop–erbium (EDFA) ditunjukkan. Sebuah pekeliling dan parutan gentian Bragg lebar jalur luas digunakan untuk menyalurkan ASE jalur–C ke dalam sistem penguat. Dengan penyuntikan sejumlah kecil ASE (20 dB pelemahan dan lebih), gandaan isyarat kecil ditingkatkan tanpa peningkatan nilai hingar berbanding penguat tanpa suntikan ASE. Peningkatan gandaan maksimum adalah sebanyak 3.5 dB dan dicapai semasa pelemahan 20 dB untuk isyarat 1580 nm. Walau bagaimanapun, jika penguat disuntik dengan jumlah ASE yang besar (VOA=0 dB), gandaan penguat didapati mendatar pada 15.2 dB dari –40 hingga –10 dBm dengan variasi gandaan kurang daripada 0.3 dB. Kuasa tepu juga bertambah dari –8 dBm (semasa tiada ASE) kepada 2 dBm (VOA=0 dB) dengan sedikit peningkatan nilai hingar. Keputusan ini menunjukkan bahawa teknik menyuntik ASE boleh digunakan sama ada untuk meningkatkan gandaan atau untuk menetapkan nilai gandaan dalam EDFA jalur–L. Kata kunci: Penetapan gandaan, penguat optik, EDFA jalur-L, penambahan gandaan, pancaran spontan terkuat The effect of injecting conventional band amplified spontaneous emission (C–band ASE) on the performance of long wavelength band erbium–doped fiber amplifier (L–band EDFA) is demonstrated. A circulator and a broadband fiber Bragg grating (FBG) were used to route a C–band ASE into amplifier system. Injection of a small amount of ASE (attenuation of 20 dB and above) improves the small signal gain with a negligible noise figure penalty compared to that of an amplifier without the ASE injection. A maximum gain improvement of 3.5 dB is obtained at an attenuation of 20 dB for signal wavelength of 1580 nm. At very large amount of ASE injection (VOA=0 dB), the gain of the amplifier is clamped at 15.2 dB from –40 to –10 dBm with a gain variation of less than 0.3 dB. The saturation power is also increased from –8 dBm (for without ASE injection) to 2 dBm (VOA=0 dB) with a slight noise figure penalty. These results show that the ASE injection technique can be used either for gain improvement or gain clamping in L–band EDFA. Keywords: Gain clamping, optical amplifier, L-band EDFA, gain enhancement, amplified spontaneous emission

Soil moisture estimation over cereals fields using l-band alos2 data (merguellil case – KAIROUAN)

2021 ◽  
Author(s):  
Emna Ayari ◽  
Zeineb Kassouk ◽  
Zohra Lili Chabaane ◽  
Safa Bousbih ◽  
Mehrez Zribi
Keyword(s):  
Soil Moisture ◽  
Cloud Model ◽  
Radar Data ◽  
Radar Signal ◽  
Biophysical Parameters ◽  
Vegetation Development ◽  
L Band ◽  
Cereal Fields ◽  
Bare Soils ◽  
Band Signal

<p>Soil moisture is a key component for water resources management especially for irrigation needs estimation. We analyze in the present study, the potential of L-band data, acquired by (Advanced Land Observing Satellite-2) ALOS-2, to retrieve soil moisture over bare soils and cereal fields located in semi-arid area in the Kairouan plain.</p><p>In this context, we evaluate radar signal sensitivity to roughness, soil moisture and vegetation biophysical parameters. Based on multi-incidence radar data (28°, 32.5° and 36°), high correlations characterize relationships between backscattering coefficients in dual-polarization (HH and HV) and root mean square of heights (Hrms) and Zs, parameters, Sensitivity of radar data to soil moisture was discussed for three classes of NDVI (less than 0.25 for bare soils and dispersed vegetation, between 0.25 and 0.5 for medium vegetation and greater than 0.5 for dense cereals). With vegetation development, where NDVI values are higher than 0.25, SAR signal remains sensitive to soil moisture in HH pol. This sensitivity to moisture disappears, in HV pol for dense vegetation. For covered fields, L-band signal is very sensitive to Vegetation Water Content (VWC), with R² values ranging between 0.76 and 0.61 in HH and HV polarization respectively.</p><p>Simulating signal behavior is carried out through various models over bare soils and covered cereal fields. Over bare soils, proposed empirical expressions, modified versions of Integral Equation Model (IEM-B) and Dubois models (Dubois-B) are evaluated, generally for HH and HV polarizations. Best consistency is observed between real data and IEM-B backscattering simulations in HH polarization. More discrepancies between real and modelled data are observed in HV polarization.</p><p>Furthermore, to simulate L-band signal behavior over covered fields, the inversion of Water Cloud Model (WCM) coupled to different bare soil models is realized through direct equations and Look-up tables. Two options of WCM, are tested (with and without soil-vegetation interaction scattering term). For the first option, results highlight the good performance of IEM-B coupled to WCM in HH polarization with RMSE value between estimated and in situ moisture measurements equal to 4.87 vol.%. By adding soil – cereal interaction term in the second option of WCM, results reveal a stable accuracy in HH polarization and an important improvement of soil moisture estimations in HV polarization, with RMSE values are ranging between 6 and 7 vol.%.</p>

High-Throughput and Long-distance Transmission with >120nm S-, C- and L-band signal in a 125m 4-Core Fiber

2021 ◽  
pp. 1-1
Author(s):  
Ben Puttnam ◽  
Ruben S Luis ◽  
Georg Rademacher ◽  
Yoshinari Awaji ◽  
Hideaki Furukawa
Keyword(s):  
High Throughput ◽  
Long Distance ◽  
Long Distance Transmission ◽  
Core Fiber ◽  
L Band ◽  
Band Signal

A field experiment on microwave forest radiometry: L-band signal behaviour for varying conditions of surface wetness

2007 ◽  
Vol 109 (1) ◽  
pp. 10-19 ◽  
Author(s):  
J.P. Grant ◽  
J.-P. Wigneron ◽  
A.A. Van de Griend ◽  
A. Kruszewski ◽  
S. Schmidl Søbjærg ◽  
...  
Keyword(s):  
Field Experiment ◽  
Surface Wetness ◽  
L Band ◽  
Band Signal
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