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1
Content available Modelling of vertical-cavity surface-emitting laser beam collimation using a nanostructured gradient index microlens
Nowosielski J M, Waddie A. J., Taghizadeh M. R., Buczynski R.
Optica Applicata
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2013
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Vol. 43, nr 4
761--772
EN
In this paper we show that the recently developed nanostructured gradient index (nGRIN) rod microlens can be utilised for the collimation of the beam generated by a vertical-cavity surface-emitting laser (VCSEL). The modelling of the nanostructured lens structure is performed using the finite difference time domain (FDTD) method with realistic nGRIN parameters and a Gaussian model of the light source. The large refractive index gradient of the nanostructured microlens allows the final microlens thickness to be only 70 μm with a diameter of 10 μm. Successful collimation of a single-mode VCSEL beam with a waist half-width of 1.53 μm is presented with a reduction in divergence half-angle from 10.1° to 3.3°. We show that the linear polarisation of the incident beam is preserved as well as presenting the tolerance of this type of lens to variations in overall thickness.
2
Content available remote Use of computer algebra system for recalculation of the fifth-order aberrations of GRIN media.
Magiera L.
Optica Applicata
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2001
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Vol. 31, nr 3
545-551
EN
The methodology of calculation of the fifth-order aberrations of gradient-index (GRIN) media by application of computer symbolic calculations (computer algebra) is presented. The software package applied was REDUCE. The results obtained enabled us to correct the results known from the literature. The designed computer program has also been added. A special computer program has also been designed.
3
Content available remote 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.
4
Content available remote Design considerations for GaAs/(AlGa)As SCH and GRIN-SCH quantum-well laser structures. II. The results
Czyszanowski T., Wasiak M., Nakwaski W.
Optica Applicata
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2001
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Vol. 31, nr 2
325-336
EN
A detailed optical model of complex multi-layered structures of the separate-confinement-heterostructure (SCH) lasers as well as graded-index (GRIN) SCH lasers presented in the first part of the paper is used to discuss some of the possible modifications of their structure to reduce room-temperature thresholds. Recommended design parameters have been found for each structure. Surprisingly, performance of relatively simple SCH lasers is found to be at least comparable with that of much more complex GRIN-SCH lasers.
5
Content available remote 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
|
2001
|
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.
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