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G. Pakulski

Bio: G. Pakulski is an academic researcher from National Research Council. The author has contributed to research in topics: Laser & Semiconductor laser theory. The author has an hindex of 13, co-authored 38 publications receiving 352 citations.

Papers
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Journal ArticleDOI
TL;DR: An InAs/InP quantum dot (QD) gain material is developed using a double cap growth procedure and GaP sublayer to tune QDs into the L-band and the relationship between pulse duration and 3-dB spectral bandwidth as a function of injection current was investigated.
Abstract: We have developed an InAs/InP quantum dot (QD) gain material using a double cap growth procedure and GaP sublayer to tune QDs into the L-band. By using it, a passive L-band mode-locked laser with pulse duration of 445 fs at the repetition rate of 46 GHz was demonstrated. The 3-dB linewidth of the RF spectrum is less than 100 KHz. The lasing threshold injection current is 24 mA with an external differential quantum efficiency of 22% and an average output power of 27 mW. The relationship between pulse duration and 3-dB spectral bandwidth as a function of injection current was investigated.

66 citations

Journal ArticleDOI
TL;DR: In this article, the tuning behavior of an external cavity laser in Littrow configuration using antireflection/high-reflection coated InAs∕InGaAsP ∕InP quantum dot laser diodes as the amplifying element was studied.
Abstract: We have studied the tuning behavior of an external cavity laser in Littrow configuration using antireflection/high-reflection coated InAs∕InGaAsP∕InP quantum dot laser diodes as the amplifying element. Adding the coatings improves the performance of the setup, and the tunability of the external cavity laser output has been increased up to 166nm. Detailed investigations have revealed that laser diode length and width influence the magnitude of the tuning range. Furthermore, the external differential quantum efficiency is systematically increasing as the external cavity laser wavelength is decreasing. These characteristics are discussed in terms of energy levels available in the inhomogeneous broadening of the self-assembled quantum dots.

54 citations

Journal ArticleDOI
TL;DR: In this paper, a non-degenerate four-wave mixing (FWM) process using CW pump and probe signals around the L-band wavelength range in an InAs/InGaAsP quantum dot semiconductor optical amplifier (QD-SOA) is experimentally demonstrated for the first time.
Abstract: A highly efficient non-degenerate four-wave mixing (FWM) process using CW pump and probe signals around the L-band wavelength range in an InAs/InGaAsP quantum dot semiconductor optical amplifier (QD-SOA) is experimentally demonstrated for the first time. The preliminary experimental results indicate that the FWM efficiency using QD-SOA is independent of the sign of the frequency detuning and decreases by less than 20 dB/decade with frequency detuning increasing.

32 citations

Journal ArticleDOI
TL;DR: In this paper, a 93-channel multiwavelength laser with maximum channel intensity non-uniformity of 3.0 dB over a wavelength range from 1638 to 1646 nm was demonstrated on the basis of a single 4500 mum-long InAs/InGaAsP quantum dot Fabry-Perot cavity chip.
Abstract: A 93-channel multiwavelength laser with maximum channel intensity non-uniformity of 3.0 dB over a wavelength range from 1638 to 1646 nm was demonstrated on the basis of a single 4500 mum-long InAs/InGaAsP quantum dot Fabry-Perot cavity chip. All channels were stable because of inhomogeneous gain broadening due to statistically distributed sizes and geometries of self-assembled quantum dots

24 citations

Journal ArticleDOI
TL;DR: In this article, the optical performance of external-cavity laser based on InAs∕InGaAsP quantum dot laser diodes is investigated and the broad electroluminescence reveals a gain spectrum with full width at half maximum of at least 175nm.
Abstract: The optical performance of external-cavity lasers based on InAs∕InGaAsP quantum dot laser diodes is investigated. The broad electroluminescence reveals a gain spectrum with full width at half maximum of at least 175nm. By fabricating as-cleaved ridge lasers of different length and width, tuning ranges as high as 110nm have been achieved at wavelengths encompassing 1.55μm. The tuning ranges and efficiencies obtained are limited by internal losses and competition between the external-cavity lasing modes and the laser diode natural lasing modes. The laser diode length is found to affect both the wavelength tuning range and the threshold current density, which is consistent with a quantum-dot type density of states.

22 citations


Cited by
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Journal ArticleDOI
TL;DR: Different techniques are proposed to enable the long range interconnection of nano-machines, deployed over distances from a few centimeters up to several meters, according to whether a fixed physical link is required for signal propagation or not, i.e., either wired or wireless communication.

266 citations

Journal ArticleDOI
TL;DR: In this paper, a III/V layer is bonded to a fully processed silicon-on-insulator wafer, and a complete high-speed optical interconnect can be realized on-chip.
Abstract: In this paper, we review the hybrid silicon photonic integration platform and its use for optical links. In this platform, a III/V layer is bonded to a fully processed silicon-on-insulator wafer. By changing the bandgap of the III/V quantum wells (QW), low-threshold-current lasers, high-speed modulators, and photodetectors can be fabricated operating at wavelengths of 1.55 μm. With a QW intermixing technology, these components can be integrated with each other and a complete high-speed optical interconnect can be realized on-chip. The hybrid silicon bonding and process technology are fully compatible with CMOS-processed wafers because high-temperature steps and contamination are avoided. Full wafer bonding is possible, allowing for low-cost and large-volume device fabrication.

219 citations

Journal ArticleDOI
TL;DR: For the first time, femtosecond pulses from a passive single-section InAs/InP quantum-dot (QD) mode-locked laser (MLL) with the active length of 456 microm and ridge width of 2.5 microm are reported.
Abstract: For the first time, we report femtosecond pulses from a passive single-section InAs/InP quantum-dot (QD) mode-locked laser (MLL) with the active length of 456 microm and ridge width of 2.5 microm at the C-band wavelength range. Without any external pulse compression, the transform-limited Gaussian-pulses are generated at the 92 GHz repetition rate with the 312 fs pulse duration, which is the shortest pulse from any directly electric-pumping semiconductor MLLs to our best knowledge. The lasing threshold injection current and external differential quantum efficiency are 17.2 mA and 38%, respectively. We have also investigated the working principles of the proposed QD MLLs.

134 citations

Journal ArticleDOI
TL;DR: Results show with QD excited state and wetting layer serving as dual-reservoir of carriers, as well as the ultra fast carrier relaxation of the QD device, this scheme is suitable for high speed Boolean logic operations.
Abstract: A scheme to realize all-optical Boolean logic functions AND, XOR and NOT using semiconductor optical amplifiers with quantum-dot active layers is studied. nonlinear dynamics including carrier heating and spectral hole-burning are taken into account together with the rate equations scheme. Results show with QD excited state and wetting layer serving as dual-reservoir of carriers, as well as the ultra fast carrier relaxation of the QD device, this scheme is suitable for high speed Boolean logic operations. Logic operation can be carried out up to speed of 250 Gb/s.

102 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of the degree of quantum confinement on the carrier recovery times in semiconductor optical amplifiers (SOAs) was assessed through an experimental comparative study of three amplifiers, one InAs-InGaAsP-In-GaA-InP quantum dot (0-D) and two quantum well (1-D), all of which operate near 1.55mum wavelengths.
Abstract: We assess the influence of the degree of quantum confinement on the carrier recovery times in semiconductor optical amplifiers (SOAs) through an experimental comparative study of three amplifiers, one InAs-InGaAsP-InP quantum dot (0-D), one InAs-InAlGaAs-InP quantum dash (1-D), and one InGaAsP-In-GaAsP-InP quantum well (2-D), all of which operate near 1.55-mum wavelengths. The short-lived (around 1 ps) and long-lived (up to 2 ns) amplitude and phase dynamics of the three devices are characterized via heterodyne pump-probe measurements. The quantum-dot device is found to have the shortest long-lived gain recovery (~80 ps) as well as gain and phase changes indicative of a smaller linewidth enhancement factor, making it the most promising for high-bit-rate applications. The quantum-dot amplifier is also found to have reduced ultrafast transients, due to a lower carrier density in the dots. The quantum-dot gain saturation characteristics and temporal dynamics also provide insight into the nature of the dot energy-level occupancy and the interactions of the dot states with the wetting layer.

98 citations