Dr. J.G. Simmons

Professor Emeritus
Department of Engineering Physics

McMaster University
1280 Main Street West, Hamilton
Ontario, Canada L8S 4L7

email:  simmonsj@mcmaster.ca
fax: (905) 527-8409

B.Sc., Ph.D. (London)

Research Interests

InP/InGaAsP Strain-Layer Quantum-Well Lasers

The effect of the quantum well properties on the performance of strain layers quantum well lasers are being investigated. These include the strain, number and well width and barrier heights of the quantum wells. The primary objective of this work is to improve the high-frequency high-power and high temperature performance of the lasers. Secondary objectives are to investigate the effects of strain on such parameters as Auger recombination and internal optical absorption, in order to gain some insight into the mechanisms by which the application of strain changes the temperature characteristics of quantum well lasers. Our investigations to date have resulted in significant improvements in device performance. These improvements include; a substantial reduction in the temperature sensitivity of laser threshold current; a reduction in laser threshold current; a substantial increase in the laser output power; an increase in the maximum operating temperature; a reduction in laser line width (important for long haul communications); a reduction in internal losses and an increased reliability for the strained quantum well lasers over unstrained lasers. This work is being done in collaboration with Nortel Technologies , formerly BNR.

Novel Optoelectronic Devices (J.G. Simmons & D.A. Thompson)

In the inversion channel technology (ICT), the growth of the semiconducting layers and the fabrication of both electronic and optoelectronic devices are highly compatible, which is conducive to integrating the two sets of devices, normally a difficult task in compound semiconducting materials. In our studies of ICT we have been concerned with two types of devices, namely the digital optoelectronic switch (DOES) and the heterojunction field effect transistor (HFET) in the AlGaAs/GaAs, InP/InGaAsP, and InGaP-InGaAs systems. The InP/InGaAsP and InGaP-InGaAs DOES devices were first fabricated at McMaster.

Split-electrode lasers are also being studied. These devices exhibit pronounced hysteresis in their optical output characteristics, and also manifest spontaneous high frequency optical oscillations in the hysterisis region. These devices have applications in marshalling and polling of optical signals in fibre-to-home optical communications. This work is being done in collaboration with Nortel Technologies, formerly BNR.

The Quantum Wire Laser (QWRL) (J.G. Simmons and D.A. Thompson)

This work represents the next logical progression in quantum confined laser structures. The QWRL has potential advantages such as a lower threshold current, a smaller temperature dependence, a higher gain, and a wider bandwidth than conventional lasers. We have already grown molecular beam epitaxial layers over nonplanar substrates to provide the two-dimensional quantum confinement required for a quantum wire. The effects of temperature on the deposition of InP over the patterned substrates, and the effects of compressive and tensile strain in the growth of InGaAs/InP superlattices into the V-grooves have been investigated. During the subsequent months, we will collaborate with NORTEL in performing low temperature spatially and spectrally resolved luminescence studies (catholuminescence and photoluminescence), in order to prove the existence of one-dimensional energy subbands, which is the characteristic signature of a quantum wire.

Ion Mixing and Implant Isolation in InP Based Materials (J.G. Simmons and D.A. Thompson)

We are using ion implantation to promote ion mixing of the barrier and quantum well regions. This mixing causes an averaging of the energy gaps of the barrier and quantum well regions, so the energy gap of the disordered material is greater than that of the lower energy gap (the quantum well region). These studies are aimed at improving the efficiency of quantum well semiconductor lasers for use in optical fibre communication systems: to increase the bandgap of the waveguide material with respect to adjacent (integrated) laser so that the light from the laser is transparent to the waveguide in the integrated studies; to improve optical confinement in waveguide and laser structures; monolithically integrate lasers and waveguides. This work is being carried out in collaboration with Nortel Technologies.

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Publications

Kelvin Prosyk, John G. Simmons and J.D. Evans, "A Systematic Empirical Study of the Effect of Well Number and Length on the Temperature Sensitivity of the Threshold Current in InGaAsP-InP MQW Lasers", IEEE J. of Quant. Electron., 34, 535-539 (1998).

G.J. Letal, J.G. Simmons, J.D. Evans and G.P. Li, "Determination of Active-Region Leakage Currents in Ridge-Waveguide Strained-Layer Quantum-Well Lasers by Varying the Ridge Width"IEEE J. of Quant. Electron., 34, 512-517 (1998). 

J. Wang, B.J. Robinson, D.A. Thompson and J.G. Simmons, "The morphology of InP/InGaAs grown by molecular beam epitaxy onto V-grooved InP substrates", J. Cryst. Growth, 173, 301-314 (1997).

J.Z. Wan, J.G. Simmons and D.A. Thompson, "Bandgap modification in Ne+-implanted In1 xGaxAsm P1-y and InAsyP1-y quantum well structures", J. Appl. Phys., 81, 765-770 (1997).

S. Nagy, B.J. Robinson, D.A. Thompson, J.G. Simmons and R.C. Blanchett, "Growth of InGaAs/InP structures by gas source molecular beam epitaxy on SiO₂-patterned substrates for optoelectronic applications", J. Cryst. Growth, 177, 1-5 (1997).

K. Prosyk, J.G. Simmons and J.D. Evans, "Well number, length and temperature dependence of the efficiency and loss in InGaAsP-InP compressively strained MQW ridge waveguide lasers at 1.3 µm", IEE Journal of Quantum Electr., 33, 1360-68 (1997).

Refereed Letters

Huang, R., J.G. Simmons, P.E. Jessop and J. Evans, "Thermal behavior of tensile-strain InGaAsP-InP lasers with varying ridgewidth", Photonic Technology Letts 9, 889-891 (1997).

Huang, R., J.G. Simmons, P.E. Jessop and J. Evans, "A relationship for temperature dependence of threshold current for 1.3-Im compressively strained-layer multiple-quantum-well lasers", PTL 892-894-897 (1997).

N. Cao, B.B. Elenkrig, J.G. Simmons and D.A. Thompson, "Bandgap blue-shift by impurity-free vacancy diffusion in 1.5 Im strained InGaAsP/InP MQW laser structure", Appl. Phys. Letts, 70, 3419-3421 (1997).

M.A. Matin, K.C. Song, B.J. Robinson, J.G. Simmons and D.A. Thompson, "High responsivity InGaAs/InP-based MSM photodetector operating at 1.3 Im wavelength", Microwave and Optical Technology Letters, 12, 310-313 (1996).