Novel all-optical 10 μm waveguide modulator based on intersubband absorption in GaAs/AlGaAs quantum wells

Julien, F. H.; Vagos, P.; Lourtioz, J.‐M.; Yang, Darang; Planel, R.

doi:10.1063/1.105925

Cited by 22 publications

(7 citation statements)

References 8 publications

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“…The P Z field is given by (17) and exhibits a phase difference n/2 relative to e ( z , t). Notice that the ESW strains of adjacent layers are always opposite in sign, acording to (12). Thus, for e1e2 > 0 the PZ fields are in opposite directions, and for ele2 < 0 the field are in the same direction.…”

Section: (13)mentioning

confidence: 97%

Multilayer Systems Driven by Elastic Standing Waves

Wen

Anastassakis

1996

Phys. Stat. Sol. (a)

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An elastic standing wave propagating in a cubic piezoelectric multilayer structure, parallel to or at an angle with the direction of growth, induces a standing wave of strains, which results in a standing wave of piezoelectric fields. The thickness of each layer is chosen equal to half the wavelength in that layer. This choice corresponds to an even-order zone-center folded acoustic mode with zero minigap. The field will produce an ac voltage signal across the system at the frequency of the wave.We have found that in well-known systems grown along [111] with a thickness of 2 pm per period, the amplitude of the signal induced by a longitudinal standing wave can be of the order of a few volts, for an energy-flux density of 0.1 W/cm2. As an ultrasonic receiver, this system is expected to have higher sensitivity than general transducers. Infrared light modulators operating in the range of GHz are also discussed as a possible application of the same system.

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Section: (13)mentioning

confidence: 97%

Multilayer Systems Driven by Elastic Standing Waves

Wen

Anastassakis

1996

Phys. Stat. Sol. (a)

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“…By substituting Eq. (2) and (3) and relation (4) 5.3 pjm, leading to an improvement of almost 2 orders of magnitude over non-phase-matched bulk. To prevent saturation of the transitions, we must limit the incident optical intensity to (C5/2) 2 times the ISBT saturation intensity, 7 but practically it will be limited by surface phenomena' 0 to _10 MW/cm 2 .…”

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confidence: 99%

“…We examine the contribution of this technique to the conversion efficiency of mid-IR radiation in GaAs phase matched by GaAs/AlGaAs n-doped quantum wells. Both the ideal case of a bulk material embedded with quantum wells and the case that is more practical as a result of growth limitations of the TM mode in a narrow dielectric waveguide 5 are considered.…”

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confidence: 99%

“…The applicability of such a technique is limited by its high sensitivity to well parameters and by the saturation of near-resonant ISBT's, 7 l 5 but the phase mismatch that may be caused by the ISBT's dispersion must be considered in any attempt to increase significantly the resonantly enhanced conversion efficiencies.' 4 ,' 5 Only on-resonant, or equally detuned, transitions of equal strength will not include such a phase mismatch.…”

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confidence: 99%

“…Unfortunately current technology limits the growth of high-quality epitaxial layers to -10 lOm, making waveguiding necessary for longer interaction distances. 5 The refractive-index contribution of ISBT's located in the core of a dielectric waveguide must be tailored to equalize the phase velocities of the first-and second-harmonic modes. Using a numerical solution 1 2 of the TM modes in arbitrarily shaped dielectric waveguides, we find that phase matching should be obtainable by use of ISBT's, provided that sufficient confinement is achieved.…”

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Intersubband-transition-induced phase matching

1994

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We suggest the use of the refractive-index changes associated with the intersubband transitions in quantum wells for phase matching in nonlinear materials.An improvement in the conversion efficiency of mid-IR secondharmonic generation by almost 2 orders of magnitude over non-phase-matched bulk GaAs is predicted. We also show that the linear phase contributions of intersubband transitions used for resonant enhancement of secondharmonic generation must be considered, as they could limit the conversion efficiency by increasing the phase mismatch on one hand or offset the bulk's dispersion and lead to phase matching on the other.The second-harmonic generation (SHG) efficiencies of nonlinear materials are often limited by their coherence lengths, 1 and schemes for phase matching or quasi-phase matching 2 need to be employed for reasonable conversion efficiencies to be achieved.Recently it was demonstrated that the refractive index of bulk material may be selectively altered by the large refractive-index contributions associated with the intersubband transitions (ISBT's) in quantum wells. 3 ' 4 In this Letter we suggest the use of these tailorable refractive-index contributions to offset the bulk's dispersion and obtain a phase-matched material at a selected wavelength. The phase matching obtained in this manner is intrinsic and requires no external process such as quasi-phase matching or angle tuning. We examine the contribution of this technique to the conversion efficiency of mid-IR radiation in GaAs phase matched by GaAs/AlGaAs n-doped quantum wells. Both the ideal case of a bulk material embedded with quantum wells and the case that is more practical as a result of growth limitations of the TM mode in a narrow dielectric waveguide 5 are considered. We consider ISBT index contributions originating either from symmetric (two-level) wells, designed for phase matching only, or from asymmetric (threelevel) quantum wells, designed both for resonant enhancement of the SHG and for phase matching. First we examine the former, in which the source of the SHG nonlinearity is the bulk material. Introduction into bulk material of a transition whose real part of the optical susceptibility will offset the bulk's dispersion will lead to phase matching. Doped quantum wells are optimal for this purpose, because the ISBT's constitute a two-level system with a designable energy-level separation and large optical dipole elements. In the following treatment we shall limit ourselves to electron ISBT's in quantum wells, but the treatment is valid for any two-level system that may be distributed uniformly (on a wavelength scale) in a dispersive host material.The ISBT's offsetting the bulk's dispersion are unavoidably 6 accompanied by loss; hence a solution of the SHG propagation equations that takes the absorption into account 7 is necessary. Maxwell's equations for a field of w and 2w frequency components (E,, and E 2 w, respectively) reduce with the slowly varying amplitude approximation 8 towhere n,,, and n 2 a,, are the first-and sec...

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Nitride intersubband devices: prospects and recent developments

Julien

Tchernycheva

Nevou

et al. 2007

Physica Status Solidi (a)

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This paper reports on GaN/AlN light‐emitting devices relying on intersubband transitions. All samples have been grown by molecular beam epitaxy. We first present a systematic investigation of single or coupled GaN/AlN quantum wells grown by MBE. We then present the recent observation of strong ISB resonant enhancement of the second‐harmonic generation of 1μm radiation. We finally report on the first observation of ISB luminescence in GaN QWs, which opens new prospects for the realization of nitride unipolar lasers based on current injection or optical pumping. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Novel all-optical 10 μm waveguide modulator based on intersubband absorption in GaAs/AlGaAs quantum wells

Cited by 22 publications

References 8 publications

Multilayer Systems Driven by Elastic Standing Waves

Multilayer Systems Driven by Elastic Standing Waves

Intersubband-transition-induced phase matching

Nitride intersubband devices: prospects and recent developments

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