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Integrated III-V Photonic Crystal--Si waveguide platform with tailored optomechanical coupling.

Tsvirkun V, Surrente A, Raineri F, Beaudoin G, Raj R, Sagnes I, Robert-Philip I, Braive R - Sci Rep (2015)

Bottom Line: Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects.To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory.This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Photonique et Nanostructures LPN-CNRS UPR-20, Route de Nozay, 91460 Marcoussis, France.

ABSTRACT
Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects. To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory. Here, we propose a novel approach to heterogeneously integrate arrays of two-dimensional photonic crystal defect cavities on top of silicon-on-insulator waveguides. The optomechanical response of these devices is investigated and evidences an optomechanical coupling involving both dispersive and dissipative mechanisms. By controlling the optical coupling between the waveguide and the photonic crystal, we were able to vary and understand the relative strength of these couplings. This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications.

No MeSH data available.


Related in: MedlinePlus

Optomechanical response for a fixed wwg.Power spectral density SP(Ω, Δ/κ) for modes (a) M1 and (b) M2, measured for wwg = 400 nm. The Lorentzian fit of the cavity mode resonance is displayed in dashed line for reference. Power spectral density at mechanical resonance SP(Ωm, Δ/κ) (open circles) as a function of the normalised detuning Δ/κ for modes (c) M1 and (d) M2 and for the same wwg. The solid lines represent the fit to the theoretical model. Contributions to transmission spectrum noise plotted in arbitrary units (blue: dispersive coupling; orange: intrinsic dissipative coupling; yellow: external dissipative coupling) for (e) M1 and (f) M2 versus Δ/κ. The inferred optomechanical coupling rates are indicated.
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f2: Optomechanical response for a fixed wwg.Power spectral density SP(Ω, Δ/κ) for modes (a) M1 and (b) M2, measured for wwg = 400 nm. The Lorentzian fit of the cavity mode resonance is displayed in dashed line for reference. Power spectral density at mechanical resonance SP(Ωm, Δ/κ) (open circles) as a function of the normalised detuning Δ/κ for modes (c) M1 and (d) M2 and for the same wwg. The solid lines represent the fit to the theoretical model. Contributions to transmission spectrum noise plotted in arbitrary units (blue: dispersive coupling; orange: intrinsic dissipative coupling; yellow: external dissipative coupling) for (e) M1 and (f) M2 versus Δ/κ. The inferred optomechanical coupling rates are indicated.

Mentions: To gain an insight into the dependence of such coupling mechanisms on the geometric features of the access waveguides, we performed a detailed analysis of the evolution of SP(Ωm, Δ/κ), measured as a function of the normalised laser detuning Δ/κ, on all the waveguide widths wwg present on our sample (all the other geometric parameters of the optomechanical resonators were kept constant). In the case of a purely dispersive coupling, SP(Ωm, Δ/κ) should be proportional to (∂T/∂Δ)2, yielding a symmetric curve with respect to Δ/κ = 0 with a mechanical amplitude at the optical resonance wavelength. Conversely, in the case of a purely dissipative coupling, the optomechanical amplitude is expected to exhibit its maximum around zero detuning. In Fig. 2(a,b), we show SP(Ω, Δ/κ) for the two lowest-frequency mechanical modes, which we refer to as M1 and M2 [see Fig. 1(d)], for wwg = 400 nm. For both modes, the mechanical frequency shifts as a result of the optical spring effect. However, unlike systems in which the optomechanical interaction is generated by intracavity fields, for which the optical spring effect vanishes at zero detuning7, our device shows the largest mechanical frequency shift around the PhC resonance, suggesting a significant dissipative coupling38. This is confirmed by the strong asymmetry of SP(Ωm, Δ/κ) with respect to a zero-laser detuning – evaluated at the mechanical resonances Ωm – for M1 and M249, as illustrated in Fig. 2(c,d), respectively. By fitting the experimental data to Eq. (1), we could extract the optomechanical coupling coefficients for M1 and M2 (see Methods for more details on the fitting procedure).


Integrated III-V Photonic Crystal--Si waveguide platform with tailored optomechanical coupling.

Tsvirkun V, Surrente A, Raineri F, Beaudoin G, Raj R, Sagnes I, Robert-Philip I, Braive R - Sci Rep (2015)

Optomechanical response for a fixed wwg.Power spectral density SP(Ω, Δ/κ) for modes (a) M1 and (b) M2, measured for wwg = 400 nm. The Lorentzian fit of the cavity mode resonance is displayed in dashed line for reference. Power spectral density at mechanical resonance SP(Ωm, Δ/κ) (open circles) as a function of the normalised detuning Δ/κ for modes (c) M1 and (d) M2 and for the same wwg. The solid lines represent the fit to the theoretical model. Contributions to transmission spectrum noise plotted in arbitrary units (blue: dispersive coupling; orange: intrinsic dissipative coupling; yellow: external dissipative coupling) for (e) M1 and (f) M2 versus Δ/κ. The inferred optomechanical coupling rates are indicated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644963&req=5

f2: Optomechanical response for a fixed wwg.Power spectral density SP(Ω, Δ/κ) for modes (a) M1 and (b) M2, measured for wwg = 400 nm. The Lorentzian fit of the cavity mode resonance is displayed in dashed line for reference. Power spectral density at mechanical resonance SP(Ωm, Δ/κ) (open circles) as a function of the normalised detuning Δ/κ for modes (c) M1 and (d) M2 and for the same wwg. The solid lines represent the fit to the theoretical model. Contributions to transmission spectrum noise plotted in arbitrary units (blue: dispersive coupling; orange: intrinsic dissipative coupling; yellow: external dissipative coupling) for (e) M1 and (f) M2 versus Δ/κ. The inferred optomechanical coupling rates are indicated.
Mentions: To gain an insight into the dependence of such coupling mechanisms on the geometric features of the access waveguides, we performed a detailed analysis of the evolution of SP(Ωm, Δ/κ), measured as a function of the normalised laser detuning Δ/κ, on all the waveguide widths wwg present on our sample (all the other geometric parameters of the optomechanical resonators were kept constant). In the case of a purely dispersive coupling, SP(Ωm, Δ/κ) should be proportional to (∂T/∂Δ)2, yielding a symmetric curve with respect to Δ/κ = 0 with a mechanical amplitude at the optical resonance wavelength. Conversely, in the case of a purely dissipative coupling, the optomechanical amplitude is expected to exhibit its maximum around zero detuning. In Fig. 2(a,b), we show SP(Ω, Δ/κ) for the two lowest-frequency mechanical modes, which we refer to as M1 and M2 [see Fig. 1(d)], for wwg = 400 nm. For both modes, the mechanical frequency shifts as a result of the optical spring effect. However, unlike systems in which the optomechanical interaction is generated by intracavity fields, for which the optical spring effect vanishes at zero detuning7, our device shows the largest mechanical frequency shift around the PhC resonance, suggesting a significant dissipative coupling38. This is confirmed by the strong asymmetry of SP(Ωm, Δ/κ) with respect to a zero-laser detuning – evaluated at the mechanical resonances Ωm – for M1 and M249, as illustrated in Fig. 2(c,d), respectively. By fitting the experimental data to Eq. (1), we could extract the optomechanical coupling coefficients for M1 and M2 (see Methods for more details on the fitting procedure).

Bottom Line: Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects.To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory.This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Photonique et Nanostructures LPN-CNRS UPR-20, Route de Nozay, 91460 Marcoussis, France.

ABSTRACT
Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects. To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory. Here, we propose a novel approach to heterogeneously integrate arrays of two-dimensional photonic crystal defect cavities on top of silicon-on-insulator waveguides. The optomechanical response of these devices is investigated and evidences an optomechanical coupling involving both dispersive and dissipative mechanisms. By controlling the optical coupling between the waveguide and the photonic crystal, we were able to vary and understand the relative strength of these couplings. This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications.

No MeSH data available.


Related in: MedlinePlus