All-optical modulation with ultrafast recovery at low pump energies in passive InGaAs/InGaAsP multiquantum well waveguides

Tsang, Hon Ki; Snow, Paul; Day, I. E.; White, I.H.; Penty, RV; Grant, R. S.; Su, Zhirui; Kennedy, G. T.; Sibbett, W.

doi:10.1063/1.108655

Cited by 21 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two different regimes can be identified: an initial fast drop in the transmittance caused by non-degenerate TPA, followed by a slower regime where FCA is dominant. We measured the FCA loss at t 0 ¼ 100 ps after the peak of the pulse (where non-degenerate TPA does not contribute), from which the generated carrier density can be obtained as 20,21 Nðt…”

mentioning

confidence: 99%

See 1 more Smart Citation

Optical free-carrier generation in silicon nano-waveguides at 1550 nm

Gil-Molina

Aldaya

Pita

et al. 2018

Applied Physics Letters

View full text Add to dashboard Cite

We report on time-resolved pump and probe characterization of linear and nonlinear optical generation of free carriers in a silicon strip nano-waveguide at the 1550 nm communication band. Analytical expressions were developed to extract the carrier density averaged along the waveguide length from the measured free-carrier absorption for different input pump power levels. This allows us to discriminate the contributions from two-photon absorption (TPA) and single-photon absorption (SPA), obtaining TPA and SPA coefficients of (1.5 6 0.1) cm/GW and (1.9 6 0.1) m À1 , respectively. Our results reveal that the effective TPA within the waveguide is higher than the value reported for bulk silicon. In addition, we find that for the waveguide under test, the carrier generation via SPA plays an important role up to $300 mW, and therefore, it must be taken into account to correctly assess free-carrier effects in silicon photonic devices.

show abstract

mentioning

confidence: 99%

“…Since the measurements are taken at the end of the waveguide, we in fact observe the longitudinally averaged carrier density, N, given by 20,21 NðtÞ…”

mentioning

confidence: 99%

Optical free-carrier generation in silicon nano-waveguides at 1550 nm

Gil-Molina

Aldaya

Pita

et al. 2018

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…Note that the switching response can be further reduced with shortening the pumping pulsewidth. 49 To perform the ultimate test, an ultrafast Er-doped fiber laser with a pulsewidth of 0.83 ps is utilized as the pumping beam (see Figure 7(a)).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…This enables wideband operation over 20 nm for the cross-wavelength inverse modulation after passing through the SiGeC waveguide. Note that the switching response can be further reduced with shortening the pumping pulsewidth . To perform the ultimate test, an ultrafast Er-doped fiber laser with a pulsewidth of 0.83 ps is utilized as the pumping beam (see Figure (a)).…”

Section: Resultsmentioning

confidence: 99%

SiGeC Waveguide for All-Optical Data Switching

et al. 2018

View full text Add to dashboard Cite

The SiGeC waveguide based ultrafast all-optical switching by using the cross-absorption modulation (XAM) effect is demonstrated to perform the wavelength conversion and format inversion of a pulsed return-to-zero on–off keying (PRZ-OOK) data stream. Under the intensively optical data-bit illumination as the pump, the two-photon absorption (TPA) effect is observed to induce free carriers in the SiGeC for absorbing the power of the probe beam. This free-carrier absorption (FCA) procedure inversely modulates the probe beam to cause the XAM switching via the intensively pumping data-bit-induced TPA/FCA process. With employing the Ge content into the SiC matrix, the picosecond free-carrier lifetime of the SiGeC can be obtained by further degrading the injected pumping energy under all-optical switching operation. With reducing the pumping energy from 0.5 nJ to 22 pJ, the effective response time of the all-optical XAM switching successfully shortens from 120 to 2 ps. Experiments declare that even a relatively low pumping energy can result in a sufficiently large XAM to perform the ultrafast all-optical switching in the SiGeC waveguide based all-optical modulator, providing the all-optical data format inversion and broadband wavelength conversion of the PRZ-OOK data stream at 1.2–6.0 Gbit/s.

show abstract

“…in [159]. Thus, it is quite straightforward to obtain an expression for the measured average carrier density 𝑁 ̅ at 𝑡 0 given by [142]:…”

Section: Pump and Probe Experimental Setupmentioning

confidence: 99%

Nonlinear optics in waveguides

Molina¹

View full text Add to dashboard Cite

In this thesis we present studies of nonlinear optics in waveguides, particularly, optical fibers and silicon nano-waveguides.In optical fibers we studied the capabilities of Four-Wave Mixing (FWM) pumped by an incoherent source in the characterization of the zero-dispersion wavelength (ZDW) and highorder dispersion. By means of this FWM-based method we were able to obtain dispersionmaps of a long fiber with a good spatial resolution. Our dispersion-mapping experiments reveal that high-order dispersion presents a higher fluctuation than that of the ZDW. In addition, by improving our experiments we were able to apply our measuring method in a short segment of fiber. This allowed us to study the bending-induced change on dispersion and explain our observations in terms of modifications of the mode confinement and fiber geometry. These studies, not reported before, are fundamental in the development of FWMbased parametric devices and were achieved thanks to an extensive experimental work, numerical modeling of fiber dispersion and nonlinear propagation, and a good understanding of the phase-matching condition of the used FWM process.Given the possibility to characterize dispersion in short fibers, we numerically explored the application of our FWM-based measuring method in silicon nano-waveguides. We obtained promising results, although neglecting single and two-photon absorption and the effects induced by the generated free carriers. Therefore, we found that the understanding freecarriers effects and their dynamics in silicon nano-waveguides is of crucial importance, not only for the application of our method but also for several studies of nonlinear optical propagation phenomena and applications of all-control of light. Initially, by means of timeresolved pump-and-probe experiments we studied optical carrier generation mechanisms and identified, for the first time, the individual contribution of single and two-photon absorption at telecommunications wavelengths. In addition, our experiments also revealed a complex carrier recombination dynamics, which we explained in terms of trap-assisted recombination. This explanation was not given before in the context of optical nano-waveguides, and is founded by the good qualitative agreement obtained between an implemented theoretical model and the observed dynamics. Our main observations are of crucial importance for several studies of linear and nonlinear propagation phenomena and applications in silicon photonics.

show abstract

All-optical modulation with ultrafast recovery at low pump energies in passive InGaAs/InGaAsP multiquantum well waveguides

Cited by 21 publications

References 9 publications

Optical free-carrier generation in silicon nano-waveguides at 1550 nm

Optical free-carrier generation in silicon nano-waveguides at 1550 nm

SiGeC Waveguide for All-Optical Data Switching

Nonlinear optics in waveguides

Contact Info

Product

Resources

About