Print ISSN: 1812-125X

Online ISSN: 2664-2530

Main Subjects : Optical fibers and communications


Influence of mode confinement factor on the modulation properties of the Vertical Cavity Surface Emitting VCSEL laser

Afrah Meshal Kareem; Younis Thanoon Qurot

Journal of Education and Science, 2021, Volume 30, Issue 5, Pages 77-85
DOI: 10.33899/edusj.2021.130566.1169

Vertical cavity surface emitting laser VCSEL is currently the main solution for many technological aspects, ultrafast optical interconnecting, Gigabit Ethernet, etc. In this paper we present the simulation results by using Optiwave™ software version 7, of the effects of optical mode confinement factor on the modulation properties)which inspected by eye diagram of the received signals)of the vertical cavity surface emitting laser VCSEL, with the range (8-20)Gbps of pseudo random bit sequence PRBS. The quality of the VCSEL modulation have been inspected by time domain signals, spectrums and eye diagram. Simulation results appeared an improvement in the characteristics of received bit sequences of (8, 10, 12.5, 16 and 20)Gbps bit rates, represented by the rising the value of quality factor QF (1.77 to 4.81) versus increasing the value of optical mode confinement factor Γ(0.2 to 0.5) respectively, and a decreasing in jitter time of superimposed traces of eye pattern and well opining eye pattern. And in the corresponding, the bit error rates BERs of the received signals have been decreased, with rising the value of mode confinement factor Γ of the laser at constant modulation index and constant temperature of the laser. Also, the VCSEL’s modulation response differences with different bitrates, causes different values of QF and BER for individual value of mode confinement factor Γ.

The influence of relative refractive index and core diameter on properties of single-mode optical fiber.

sama mumtaz aldabagh; Manaf Saeed

Journal of Education and Science, 2020, Volume 29, Issue 4, Pages 124-139
DOI: 10.33899/edusj.2020.126908.1063

A study of the influence of the parameters design, such as the refractive index of the core, the cladding and the radius of the core on propagation constant (β) of single-mode optical fiber in optical communication region (1.2-1.6) m have been investigated. Material, waveguide, and profile dispersions are analyzed and investigated. Three models of optical fibers with different relative refractive indices () (0.004, 0.007, 0.01) at a wavelength equal 1.55 m, and three models of core radius (3,4,5) m is taken in the count. Numerical simulations and modeling are arranged depending on weakly guiding approximation for solving homogeneous wave equation derived from Maxwell’s equations. Our modeling solved by the aid of MATLAB software. Material and profile dispersion have no significant change for various relative refractive index, while waveguide dispersion is affected by the change of relative refractive index. the waveguide dispersion increased by increasing core diameter and the profile dispersion decreased as the core diameter increased. There is no effect on martial dispersion by increasing the core diameter.