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Polarization properties of nematic liquid crystal cell with tapered optical fiber

Marć Paweł, Stasiewicz K., Korec J., Jaroszewicz L. R., Kula P.

Opto-Electronics Review

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2019

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Vol. 27, No. 4

321--328

EN

In the paper, an extended analysis of the polarization properties of a liquid crystal cell with a biconically tapered single-mode telecommunication optical fiber was presented. These properties are a result of a sample geometry and used LC materials. They were analyzed by using two theoretical models based on the matrix decomposition methods, i.e., polar and singular-value one. By measuring Mueller matrices, information about losses, depolarization, dichroism and birefringence was obtained. In the experiment two types of tested samples filled with well-known 6CHBT and E7 liquid crystals were prepared and all optical parameters were shown as the voltage dependence. The tested samples have dichroic properties and for both models calculated PDL is similar and it increases from 2.6 to 6.6 dB for E7 and from 0.4 to 2.7 dB for 6CHBT with voltage changes within the range of 40 – 190 V. Optical losses simultaneously decrease from 30 dB to 27 dB and from 36 dB to 28 dB, respectively. The birefringence properties cannot be directly comparable due to differences between both applied models but voltage fluctuations of these parameters are not significant. These results confirm expected dichroic properties of designed device and complete knowledge about its working principles. Moreover, presented analysis validates usefulness of the singular-value decomposition model applied to dichroic optical fiber elements.

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Operation of arsenide diode lasers at elevated temperatures

Czyszanowski T.

Optica Applicata

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2001

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Vol. 31, nr 2

301-311

EN

Some design modification and optimisation of the GaAs/(AlGa)As separate-confinement-heterostructure (SCH) as well as the graded-index separate-confinement-heterostructure (GRIN-SCH) semiconductor lasers are discussed to reduce their threshold concentrations at elevated temperatures. A detailed optical model of arsenide lasers is used to compare an impact of some structural details on lasing thresholds at various temperatures. In the analysis, both optical gain and losses are modelled rigorously. It has been demonstrated that operation of the arsenide lasers considered is not changing dramatically at elevated temperatures not exceeding 400 K.

3

Design considerations for GaAs/(AlGa)As SCH and GRIN-SCH quantum-well laser structures. I. The model

Czyszanowski T., Wasiak M., Nakwaski W.

Optica Applicata

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2001

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Vol. 31, nr 2

313-323

EN

Some design modifications and optimization of the GaAs/(AlGa)As separate-confinement-heterostructure (SCH) as well as graded-index separate-confinement-heterostructure (GRIN-SCH) semiconductor lasers to reduce their room-temperature (RT) thresholds are discussed. To this end, a detailed optical model of arsenide diode lasers is developed and used to compare the impact of some structure details on RT lasing thresholds. In the model presented in the first part of the paper, both optical gain and losses are modeled rigorously. Optical fields within complex multi-layered structures of the SCH lasers are found using the downhill method. Threshold carrier concentrations are determined from the general balance of radiation gain and losses. As a result of the simulation, recommended basic design parameters for the above structures are deduced in the second part of the paper.