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Paul Seidler - One of the best experts on this subject based on the ideXlab platform.
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nanoscopic charge fluctuations in a Gallium Phosphide waveguide measured by single molecules
2021Co-Authors: A B Shkarin, Simon Honl, Paul Seidler, Dominik Rattenbacher, Jan Renger, Tobias Utikal, Stephan Gotzinger, Vahid SandoghdarAbstract:We present efficient evanescent coupling of single organic molecules to a Gallium Phosphide (GaP) subwavelength waveguide (nanoguide) decorated with microelectrodes. By monitoring their Stark shifts, we reveal that the coupled molecules experience fluctuating electric fields. We analyze the spectral dynamics of different molecules over a large range of optical powers in the nanoguide to show that these fluctuations are light-induced and local. A simple model is developed to explain our observations based on the optical activation of charges at an estimated mean density of $2.5\ifmmode\times\else\texttimes\fi{}{10}^{22}\text{ }\text{ }{\mathrm{m}}^{\ensuremath{-}3}$ in the GaP nanostructure. Our work showcases the potential of organic molecules as nanoscopic sensors of the electric charge as well as the use of GaP nanostructures for integrated quantum photonics.
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optomechanics with one dimensional Gallium Phosphide photonic crystal cavities
2019Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Dalziel J Wilson, Lukas Czornomaz, Paul SeidlerAbstract:Gallium Phosphide offers an attractive combination of a high refractive index (n>3 for vacuum wavelengths up to 4 μm) and a wide electronic bandgap (2.26 eV), enabling optical cavities with small mode volumes and low two-photon absorption at telecommunication wavelengths. Heating due to strongly confined light fields is therefore greatly reduced. Here, we investigate the benefits of these properties for cavity optomechanics. Utilizing a recently developed fabrication scheme based on direct wafer bonding, we realize integrated one-dimensional photonic crystal cavities made of Gallium Phosphide with optical quality factors as high as 1.1×105. We optimize their design to couple the optical eigenmode at ∼200 THz via radiation pressure to a co-localized mechanical mode with a frequency of 3 GHz, yielding sideband-resolved devices. The high vacuum optomechanical coupling rate (g0=2π×400 kHz) permits amplification of the mechanical mode into the so-called mechanical lasing regime with input power as low as ∼20 μW. The observation of mechanical lasing implies a multiphoton cooperativity of C>1, an important threshold for the realization of quantum state transfer protocols. Because of the reduced thermo-optic resonance shift, optomechanically induced transparency can be detected at room temperature even in non-sideband-resolved devices in addition to the normally observed optomechanically induced absorption. Considering that GaP is also piezoelectric, these results establish GaP as an attractive material for future electro–opto-mechanical systems.
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optomechanics with one dimensional Gallium Phosphide photonic crystal cavities
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Dalziel J Wilson, Lukas Czornomaz, Paul SeidlerAbstract:Gallium Phosphide offers an attractive combination of a high refractive index ($n>3$ for vacuum wavelengths up to 4 {\mu}m) and a wide electronic bandgap (2.26 eV), enabling optical cavities with small mode volumes and low two-photon absorption at telecommunication wavelengths. Heating due to strongly confined light fields is therefore greatly reduced. Here, we investigate the benefits of these properties for cavity optomechanics. Utilizing a recently developed fabrication scheme based on direct wafer bonding, we realize integrated one-dimensional photonic crystal cavities made of Gallium Phosphide with optical quality factors as high as $1.1\times10^5$. We optimize their design to couple the optical eigenmode at $\approx 200$ THz via radiation pressure to a co-localized mechanical mode with a frequency of 3 GHz, yielding sideband-resolved devices. The high vacuum optomechanical coupling rate ($g_0=2\pi\times 400$ kHz) permits amplification of the mechanical mode into the so-called mechanical lasing regime with input power as low as $\approx 20$ {\mu}W. The observation of mechanical lasing implies a multiphoton cooperativity of $C>1$, an important threshold for the realization of quantum state transfer protocols. Because of the reduced thermo-optic resonance shift, optomechanically induced transparency can be detected at room temperature in addition to the normally observed optomechanically induced absorption.
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integrated Gallium Phosphide nonlinear photonics
2018Co-Authors: Dalziel J Wilson, Katharina Schneider, Simon Hoenl, Miles Anderson, Tobias J Kippenberg, Paul SeidlerAbstract:Gallium Phosphide (GaP) is an indirect bandgap semiconductor used widely in solid-state lighting. Despite numerous intriguing optical properties---including large $\chi^{(2)}$ and $\chi^{(3)}$ coefficients, a high refractive index ($>3$), and transparency from visible to long-infrared wavelengths ($0.55-11\,\mu$m)---its application as an integrated photonics material has been little studied. Here we introduce GaP-on-insulator as a platform for nonlinear photonics, exploiting a direct wafer bonding approach to realize integrated waveguides with 1.2 dB/cm loss in the telecommunications C-band (on par with Si-on-insulator). High quality $(Q> 10^5)$, grating-coupled ring resonators are fabricated and studied. Employing a modulation transfer approach, we obtain a direct experimental estimate of the nonlinear index of GaP at telecommunication wavelengths: $n_2=1.2(5)\times 10^{-17}\,\text{m}^2/\text{W}$. We also observe Kerr frequency comb generation in resonators with engineered dispersion. Parametric threshold powers as low as 3 mW are realized, followed by broadband ($>100$ nm) frequency combs with sub-THz spacing, frequency-doubled combs and, in a separate device, efficient Raman lasing. These results signal the emergence of GaP-on-insulator as a novel platform for integrated nonlinear photonics.
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Gallium Phosphide on silicon dioxide photonic devices
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Pol Welter, Herwig Hahn, Lukas Czornomaz, Paul SeidlerAbstract:The development of integrated photonic circuits utilizing Gallium Phosphide requires a robust, scalable process for fabrication of GaP-on-insulator devices. Here, we present the first GaP photonic devices on SiO2. The process exploits direct wafer bonding of a GaP/Al x Ga1- x P/GaP heterostructure onto a SiO2-on-Si wafer followed by the removal of the GaP substrate and the Al x Ga1- x P stop layer. Photonic devices such as grating couplers, waveguides, and ring resonators are patterned by inductively coupled-plasma reactive-ion etching in the top GaP device layer. The peak coupling efficiency of the fabricated grating couplers is as high as −4.8 dB. Optical quality factors of 20 000 as well as second- and third-harmonic generation are observed with the ring resonators. Because the large bandgap of GaP provides for low two-photon absorption at telecommunication wavelengths, the high-yield fabrication of GaP-on-insulator photonic devices enabled by this work is especially interesting for applications in nanophotonics, where high quality factors or low mode volumes can produce high electric field intensities. The large bandgap also enables integrated photonic devices operating at visible wavelengths.
Katharina Schneider - One of the best experts on this subject based on the ideXlab platform.
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optomechanics with one dimensional Gallium Phosphide photonic crystal cavities
2019Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Dalziel J Wilson, Lukas Czornomaz, Paul SeidlerAbstract:Gallium Phosphide offers an attractive combination of a high refractive index (n>3 for vacuum wavelengths up to 4 μm) and a wide electronic bandgap (2.26 eV), enabling optical cavities with small mode volumes and low two-photon absorption at telecommunication wavelengths. Heating due to strongly confined light fields is therefore greatly reduced. Here, we investigate the benefits of these properties for cavity optomechanics. Utilizing a recently developed fabrication scheme based on direct wafer bonding, we realize integrated one-dimensional photonic crystal cavities made of Gallium Phosphide with optical quality factors as high as 1.1×105. We optimize their design to couple the optical eigenmode at ∼200 THz via radiation pressure to a co-localized mechanical mode with a frequency of 3 GHz, yielding sideband-resolved devices. The high vacuum optomechanical coupling rate (g0=2π×400 kHz) permits amplification of the mechanical mode into the so-called mechanical lasing regime with input power as low as ∼20 μW. The observation of mechanical lasing implies a multiphoton cooperativity of C>1, an important threshold for the realization of quantum state transfer protocols. Because of the reduced thermo-optic resonance shift, optomechanically induced transparency can be detected at room temperature even in non-sideband-resolved devices in addition to the normally observed optomechanically induced absorption. Considering that GaP is also piezoelectric, these results establish GaP as an attractive material for future electro–opto-mechanical systems.
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optomechanics with one dimensional Gallium Phosphide photonic crystal cavities
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Dalziel J Wilson, Lukas Czornomaz, Paul SeidlerAbstract:Gallium Phosphide offers an attractive combination of a high refractive index ($n>3$ for vacuum wavelengths up to 4 {\mu}m) and a wide electronic bandgap (2.26 eV), enabling optical cavities with small mode volumes and low two-photon absorption at telecommunication wavelengths. Heating due to strongly confined light fields is therefore greatly reduced. Here, we investigate the benefits of these properties for cavity optomechanics. Utilizing a recently developed fabrication scheme based on direct wafer bonding, we realize integrated one-dimensional photonic crystal cavities made of Gallium Phosphide with optical quality factors as high as $1.1\times10^5$. We optimize their design to couple the optical eigenmode at $\approx 200$ THz via radiation pressure to a co-localized mechanical mode with a frequency of 3 GHz, yielding sideband-resolved devices. The high vacuum optomechanical coupling rate ($g_0=2\pi\times 400$ kHz) permits amplification of the mechanical mode into the so-called mechanical lasing regime with input power as low as $\approx 20$ {\mu}W. The observation of mechanical lasing implies a multiphoton cooperativity of $C>1$, an important threshold for the realization of quantum state transfer protocols. Because of the reduced thermo-optic resonance shift, optomechanically induced transparency can be detected at room temperature in addition to the normally observed optomechanically induced absorption.
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integrated Gallium Phosphide nonlinear photonics
2018Co-Authors: Dalziel J Wilson, Katharina Schneider, Simon Hoenl, Miles Anderson, Tobias J Kippenberg, Paul SeidlerAbstract:Gallium Phosphide (GaP) is an indirect bandgap semiconductor used widely in solid-state lighting. Despite numerous intriguing optical properties---including large $\chi^{(2)}$ and $\chi^{(3)}$ coefficients, a high refractive index ($>3$), and transparency from visible to long-infrared wavelengths ($0.55-11\,\mu$m)---its application as an integrated photonics material has been little studied. Here we introduce GaP-on-insulator as a platform for nonlinear photonics, exploiting a direct wafer bonding approach to realize integrated waveguides with 1.2 dB/cm loss in the telecommunications C-band (on par with Si-on-insulator). High quality $(Q> 10^5)$, grating-coupled ring resonators are fabricated and studied. Employing a modulation transfer approach, we obtain a direct experimental estimate of the nonlinear index of GaP at telecommunication wavelengths: $n_2=1.2(5)\times 10^{-17}\,\text{m}^2/\text{W}$. We also observe Kerr frequency comb generation in resonators with engineered dispersion. Parametric threshold powers as low as 3 mW are realized, followed by broadband ($>100$ nm) frequency combs with sub-THz spacing, frequency-doubled combs and, in a separate device, efficient Raman lasing. These results signal the emergence of GaP-on-insulator as a novel platform for integrated nonlinear photonics.
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Gallium Phosphide on silicon dioxide photonic devices
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Pol Welter, Herwig Hahn, Lukas Czornomaz, Paul SeidlerAbstract:The development of integrated photonic circuits utilizing Gallium Phosphide requires a robust, scalable process for fabrication of GaP-on-insulator devices. Here, we present the first GaP photonic devices on SiO2. The process exploits direct wafer bonding of a GaP/Al x Ga1- x P/GaP heterostructure onto a SiO2-on-Si wafer followed by the removal of the GaP substrate and the Al x Ga1- x P stop layer. Photonic devices such as grating couplers, waveguides, and ring resonators are patterned by inductively coupled-plasma reactive-ion etching in the top GaP device layer. The peak coupling efficiency of the fabricated grating couplers is as high as −4.8 dB. Optical quality factors of 20 000 as well as second- and third-harmonic generation are observed with the ring resonators. Because the large bandgap of GaP provides for low two-photon absorption at telecommunication wavelengths, the high-yield fabrication of GaP-on-insulator photonic devices enabled by this work is especially interesting for applications in nanophotonics, where high quality factors or low mode volumes can produce high electric field intensities. The large bandgap also enables integrated photonic devices operating at visible wavelengths.
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Gallium Phosphide microresonator frequency combs conference presentation
2018Co-Authors: Simon Honl, Katharina Schneider, Dalziel J Wilson, Miles Anderson, Tobias J Kippenberg, Paul SeidlerAbstract:Gallium Phosphide (GaP) is an attractive material for non-linear optics because of its broad transparency window (λ_vac > 548 nm) and large Kerr coefficient (n_2 ~ 6 × 10^-18 m^2/W). Though well-established in the semiconductor industry as a substrate for visible LEDs, its use in integrated photonics remains limited due to fabrication challenges. Recently we have developed a method to integrate high quality, epitaxially-grown GaP onto silica (SiO2) based on direct wafer bonding to an oxidized silicon carrier wafer. Here we exploit this platform to realize unprecedentedly low loss (Q > 3 × 10^5) GaP-on-SiO2 waveguide resonators which have been dispersion-engineered to support Kerr frequency comb generation in the C-band. Single-mode, grating-coupled ring resonators with radii from 10 – 100 μm are investigated. The threshold for parametric conversion is observed at input powers as little as 10 mW, followed by 0.1 – 1 THz frequency comb generation over a range exceeding 400 nm, in addition to strong second- and third-harmonic generation. Building on this advance, we discuss the prospects for low-noise, sub-mW-threshold soliton frequency combs with center frequencies tunable from the mid-IR to the near-IR. Applications of such devices range from precision molecular spectroscopy to ultrafast pulse generation to massively parallel coherent optical communication.
Peter G Schunemann - One of the best experts on this subject based on the ideXlab platform.
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femtosecond optical parametric oscillator continuously tunable across 3 6 8 μm based on orientation patterned Gallium Phosphide
2019Co-Authors: Callum F Odonnell, Peter G Schunemann, Chaitanya S Kumar, M EbrahimzadehAbstract:We report a synchronously-pumped femtosecond optical parametric oscillator (OPO) based on orientation-patterned Gallium Phosphide (OP-GaP), providing continuously tunable mid-infrared (mid-IR) idler radiation across 3570–7892 nm (2801–1267 cm−1), by exploiting pump wavelength tuning. We generate up to 54 mW of output average power at 80 MHz, and quantum conversion efficiencies up to 28.9% are achieved by use of synchronized pump retroreflection. With the inclusion of intracavity dispersion compensation in an OP-GaP OPO, near-transform-limited signal pulse durations of 112 fs at 1288 nm are measured, and peak powers up to 3 kW in the mid-IR are inferred. Finally, evidence of three-photon absorption is observed and characterized near the pump wavelength.
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Long-wave infrared generation from femtosecond and picosecond optical parametric oscillators based on orientation-patterned Gallium Phosphide
2018Co-Authors: Luke Maidment, Peter G Schunemann, Oguzhan Kara, Jonathon Piper, Kenneth Mcewan, Derryck T. ReidAbstract:Optical parametric oscillators synchronously pumped with 1-µm femtosecond and picosecond lasers are used to generate long-wave mid-infrared radiation using the nonlinear material orientation-patterned Gallium Phosphide. The output spectra from the femtosecond OPO are measured, demonstrating tuning based on grating period and temperature from 5.5 to 13.0 µm. The picosecond OPO produces 137 mW at 7.87 µm, representing the first picosecond-pumped OPO using orientation Gallium Phosphide.
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multimilliwatt tunable continuous wave mid infrared generation across 4 6 4 7 μm based on orientation patterned Gallium Phosphide
2018Co-Authors: Kavita Devi, Peter G Schunemann, A Padhye, M EbrahimzadehAbstract:We report the generation of tunable continuous-wave (cw) mid-infrared (mid-IR) radiation across 4608-4694 nm using the new nonlinear material, orientation-patterned Gallium Phosphide (OP-GaP). By exploiting difference-frequency mixing between a cw Tm-fiber laser and a home-built cw optical parametric oscillator in a 40-mm-long crystal, we have generated up to 43 mW of cw output power, with >30 mW across >95% of the mid-IR tuning range. The output at 4608 nm exhibits high beam quality with a passive power stability of 2.5% rms over 1.5 min. The temperature acceptance bandwidth of the OP-GaP crystal has been measured and compared with theory. The performance of the mid-IR source at high pump powers and polarization-dependent transmission in OP-GaP has been investigated.
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difference frequency generation in the mid infrared with orientation patterned Gallium Phosphide crystals
2016Co-Authors: G Insero, Peter G Schunemann, Cecilia Clivati, D Dambrosio, Paolo De Natale, Gabriele Santambrogio, J J Zondy, S BorriAbstract:We report on the generation of coherent mid-infrared radiation around 5.85 μm by difference frequency generation (DFG) of a continuous-wave Nd:YAG laser at 1064 nm and a diode laser at 1301 nm in an orientation-patterned Gallium Phosphide (OP-GaP) crystal. We provide the first characterization of the linear, thermo-optic, and nonlinear properties of OP-GaP in a DFG configuration. Moreover, by comparing the experimental efficiency to Gaussian beam DFG theory, we derive an effective nonlinear coefficient d=17(3) pm/V for first-order quasi-phase-matched OP-GaP. The temperature and signal wavelength tuning curves are in qualitative agreement with theoretical modeling.
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molecular fingerprint region spectroscopy from 5 to 12 μm using an orientation patterned Gallium Phosphide optical parametric oscillator
2016Co-Authors: Luke Maidment, Peter G Schunemann, D T ReidAbstract:We report a femtosecond optical parametric oscillator (OPO) based on the new semiconductor gain material orientation-patterned Gallium Phosphide (OP-GaP), which enables the production of high-repetition-rate femtosecond pulses spanning 5–12 μm with average powers in the few to tens of milliwatts range. This is the first example of a broadband OPO operating across the molecular fingerprint region, and we demonstrate its potential by conducting broadband Fourier-transform spectroscopy using water vapor and a polystyrene reference standard.
Jelena Vuckovic - One of the best experts on this subject based on the ideXlab platform.
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second harmonic generation in Gallium Phosphide photonic crystal nanocavities with ultralow cw pump power
2010Co-Authors: Kelley Rivoire, Fariba Hatami, Ziliang Lin, Ted W Masselink, Jelena VuckovicAbstract:Using photonic crystal nanocavities fabricated in the semiconductor Gallium Phosphide, we demonstrate second harmonic generation with input continuous wave powers of nanowatts (at 1550 nm).
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second harmonic generation in Gallium Phosphide photonic crystal nanocavities with ultralow continuous wave pump power
2009Co-Authors: Kelley Rivoire, Fariba Hatami, Ziliang Lin, Ted W Masselink, Jelena VuckovicAbstract:We demonstrate second harmonic generation in photonic crystal nanocavities fabricated in the semiconductor Gallium Phosphide. We observe second harmonic radiation at 750 nm with input powers of only nanowatts coupled to the cavity and conversion efficiency $P_{\rm out}/P_{\rm in, coupled}^2 = 430%/{\rm W}$. The large electronic band gap of GaP minimizes absorption loss, allowing efficient conversion. Our results are promising for integrated, low-power light sources and on-chip reduction of input power in other nonlinear processes.
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Gallium Phosphide photonic crystal nanocavities in the visible
2008Co-Authors: Kelley Rivoire, Andrei Faraon, Jelena VuckovicAbstract:Photonic crystal nanocavities at visible wavelengths are fabricated in a high refractive index Gallium Phosphide membrane. The cavities show resonances at wavelengths as low as 645 nm at room temperature, with quality factors 500-1700.
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Gallium Phosphide photonic crystal nanocavities in the visible
2008Co-Authors: Kelley Rivoire, Andrei Faraon, Jelena VuckovicAbstract:Photonic crystal nanocavities at visible wavelengths are fabricated in a high refractive index (n>3.2) Gallium Phosphide membrane. The cavities are probed via a cross-polarized reflectivity measurement and show resonances at wavelengths as low as 645 nm at room temperature, with quality factors between 500 and 1700 for modes with volumes 0.7(λ/n)3. These structures could be employed for submicron scale optoelectronic devices in the visible, and for coupling to emitters with resonances in the visible such as nitrogen vacancy centers, and biomolecules and organic molecules.
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Gallium Phosphide photonic crystal nanocavities in the visible
2008Co-Authors: Kelley Rivoire, Andrei Faraon, Jelena VuckovicAbstract:Photonic crystal nanocavities at visible wavelengths are fabricated in a high refractive index (n>3.2) Gallium Phosphide membrane. The cavities are probed via a cross-polarized reflectivity measurement and show resonances at wavelengths as low as 645 nm at room temperature, with quality factors between 500 and 1700 for modes with volumes 0.7(lambda/n)^3. These structures could be employed for submicron scale optoelectronic devices in the visible, and for coupling to novel emitters with resonances in the visible such as nitrogen vacancy centers, and bio- and organic molecules.
Yannick Baumgartner - One of the best experts on this subject based on the ideXlab platform.
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optomechanics with one dimensional Gallium Phosphide photonic crystal cavities
2019Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Dalziel J Wilson, Lukas Czornomaz, Paul SeidlerAbstract:Gallium Phosphide offers an attractive combination of a high refractive index (n>3 for vacuum wavelengths up to 4 μm) and a wide electronic bandgap (2.26 eV), enabling optical cavities with small mode volumes and low two-photon absorption at telecommunication wavelengths. Heating due to strongly confined light fields is therefore greatly reduced. Here, we investigate the benefits of these properties for cavity optomechanics. Utilizing a recently developed fabrication scheme based on direct wafer bonding, we realize integrated one-dimensional photonic crystal cavities made of Gallium Phosphide with optical quality factors as high as 1.1×105. We optimize their design to couple the optical eigenmode at ∼200 THz via radiation pressure to a co-localized mechanical mode with a frequency of 3 GHz, yielding sideband-resolved devices. The high vacuum optomechanical coupling rate (g0=2π×400 kHz) permits amplification of the mechanical mode into the so-called mechanical lasing regime with input power as low as ∼20 μW. The observation of mechanical lasing implies a multiphoton cooperativity of C>1, an important threshold for the realization of quantum state transfer protocols. Because of the reduced thermo-optic resonance shift, optomechanically induced transparency can be detected at room temperature even in non-sideband-resolved devices in addition to the normally observed optomechanically induced absorption. Considering that GaP is also piezoelectric, these results establish GaP as an attractive material for future electro–opto-mechanical systems.
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optomechanics with one dimensional Gallium Phosphide photonic crystal cavities
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Dalziel J Wilson, Lukas Czornomaz, Paul SeidlerAbstract:Gallium Phosphide offers an attractive combination of a high refractive index ($n>3$ for vacuum wavelengths up to 4 {\mu}m) and a wide electronic bandgap (2.26 eV), enabling optical cavities with small mode volumes and low two-photon absorption at telecommunication wavelengths. Heating due to strongly confined light fields is therefore greatly reduced. Here, we investigate the benefits of these properties for cavity optomechanics. Utilizing a recently developed fabrication scheme based on direct wafer bonding, we realize integrated one-dimensional photonic crystal cavities made of Gallium Phosphide with optical quality factors as high as $1.1\times10^5$. We optimize their design to couple the optical eigenmode at $\approx 200$ THz via radiation pressure to a co-localized mechanical mode with a frequency of 3 GHz, yielding sideband-resolved devices. The high vacuum optomechanical coupling rate ($g_0=2\pi\times 400$ kHz) permits amplification of the mechanical mode into the so-called mechanical lasing regime with input power as low as $\approx 20$ {\mu}W. The observation of mechanical lasing implies a multiphoton cooperativity of $C>1$, an important threshold for the realization of quantum state transfer protocols. Because of the reduced thermo-optic resonance shift, optomechanically induced transparency can be detected at room temperature in addition to the normally observed optomechanically induced absorption.
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Gallium Phosphide on silicon dioxide photonic devices
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Pol Welter, Herwig Hahn, Lukas Czornomaz, Paul SeidlerAbstract:The development of integrated photonic circuits utilizing Gallium Phosphide requires a robust, scalable process for fabrication of GaP-on-insulator devices. Here, we present the first GaP photonic devices on SiO2. The process exploits direct wafer bonding of a GaP/Al x Ga1- x P/GaP heterostructure onto a SiO2-on-Si wafer followed by the removal of the GaP substrate and the Al x Ga1- x P stop layer. Photonic devices such as grating couplers, waveguides, and ring resonators are patterned by inductively coupled-plasma reactive-ion etching in the top GaP device layer. The peak coupling efficiency of the fabricated grating couplers is as high as −4.8 dB. Optical quality factors of 20 000 as well as second- and third-harmonic generation are observed with the ring resonators. Because the large bandgap of GaP provides for low two-photon absorption at telecommunication wavelengths, the high-yield fabrication of GaP-on-insulator photonic devices enabled by this work is especially interesting for applications in nanophotonics, where high quality factors or low mode volumes can produce high electric field intensities. The large bandgap also enables integrated photonic devices operating at visible wavelengths.
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Gallium Phosphide on silicon dioxide photonic devices
2018Co-Authors: Katharina Schneider, Yannick Baumgartner, Pol Welter, Herwig Hahn, Lukas Czornomaz, Paul SeidlerAbstract:The development of integrated photonic circuits utilizing Gallium Phosphide requires a robust, scalable process for fabrication of GaP-on-insulator devices. Here we present the first GaP photonic devices on SiO$_2$. The process exploits direct wafer bonding of a GaP/Al$_x$Ga$_{1-x}$P/GaP heterostructure onto a SiO$_2$-on-Si wafer followed by removal of the GaP substrate and the Al$_x$Ga$_{1-x}$P stop layer. Photonic devices such as grating couplers, waveguides, and ring resonators are patterned by inductively coupled-plasma reactive-ion etching in the top GaP device layer. The peak coupling efficiency of the fabricated grating couplers is as high as 4.8 dB. Optical quality factors of 17000 as well as second- and third-harmonic generation are observed with the ring resonators. Because the large bandgap of GaP provides for low two-photon absorption at telecommunication wavelengths, the high-yield fabrication of GaP-on-insulator photonic devices enabled by this work is especially interesting for applications in nanophotonics, where high quality factors or low mode volumes can produce high electric field intensities. The large bandgap also enables integrated photonic devices operating at visible wavelengths.
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Optomechanics with one-dimensional Gallium Phosphide photonic crystal cavities
2017Co-Authors: Katharina Schneider, Yannick Baumgartner, Simon Honl, Pol Welter, Herwig Hahn, Lukas Czornomaz, Paul SeidlerAbstract:We present the first investigation of optomechanics in an integrated one-dimensional Gallium Phosphide (GaP) photonic crystal cavity. The devices are fabricated with a newly developed process flow for integration of GaP devices on silicon dioxide (SiO2) involving direct wafer bonding of an epitaxial GaP/AlxGa1-xP/GaP heterostructure onto an oxidized silicon wafer. Device designs are transferred into the top GaP layer by inductively-coupled-plasma reactive ion etching and made freestanding by removal of the underlying SiO2. Finite-element simulations of the photonic crystal cavities predict optical quality factors greater than 106 at a design wavelength of 1550 nm and optomechanical coupling rates as high as 900 kHz for the mechanical breathing mode localized in the center of the photonic crystal cavity. The first fabricated devices exhibit optical quality factors as high as 6.5 × 104, and the mechanical breathing mode is found to have a vacuum coupling rate of 200 kHz at a frequency of 2.59 GHz. These results, combined with low two-photon absorption at telecommunication wavelengths and piezoelectric behavior, make GaP a promising material for the development of future nanophotonic devices in which optical and mechanical modes as well as high-frequency electrical signals interact.
