Showing 3 results for parvizi
Dr. Roghaieh Parvizi,
Volume 6, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 6, No 2, Summer-Fall 2012)
Abstract
we investigate the temperature-dependences of the Brillouin frequency shift in three different kind of single-mode fibers using a heterodyne method for sensing temperature. Positive dependences coefficients of 0.77, 0.56 and 1.45MHz/0C are demonstrated for 25 km long single-mode fiber, 10 km long non-zero dispersion shifted fiber and 100 m photonic crystal fiber, respectively. The results indicate that microstructure fibers with a partially Ge-doped small core have great potential for fiber Brillouin distributed sensing.
Dr Roghaieh Parvizi,
Volume 7, Issue 1 (International Journal of Optics and Photonics (IJOP) Vol 7, No 1, Winter-Spring 2013)
Abstract
We have investigated and developed a theoretical approach to explore stimulated Brillouin scattering (SBS) phenomena in single mode fiber. SBS happening threshold power condition has been studied in terms of fiber parameters and input pump power. To assess threshold power precisely, the pump depletion effect and fiber loss has been included by employing 1% criterion. The threshold exponential gain Gth can be anticipated by this simulation which strongly depends on the fiber length Brillouin gain content and effective area. The value of Gth is not a constant as usually assumed in the literature and its value is 4 for the longer lengths and between 10 and 18 is for relatively shorter lengths. This simulation can anticipate the optimum length of fiber against the every launched pump power to generate SBS effect.
Saeed Azad, Roghaieh Parvizi, Ebrahim Sadeghi,
Volume 12, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 12, No 2, Summer-Fall 2018)
Abstract
This work presents ZnO nanorods coated multimode optical fiber sensing behavior in response to ethanol solution. The sensor operates based on modulation of light intensity which arises from manipulation of light interaction with the ambient environment in sensing region. For this purpose, two steps are experimentally applied here; etching and then coating fiber with ZnO nanorods to provide stronger evanescent waves causing an enhanced interaction. Long length of fiber (15 mm) was etched uniformly and then well-ordered ZnO nanorods were grown hydrothermally on the core of optical fiber. Fiber coated with ZnO demonstrated an enhanced sensing performances such that response time decreased to 0.6s, linearity increased to 97% and sensitivity improved. Applicable features of the proposed device such as fast response time and high linearity make it favorable candidate for fiber optic sensing applications.
