We demonstrate low-loss Ge-rich Si<sub>0.2</sub>Ge<sub>0.8</sub> waveguid... more We demonstrate low-loss Ge-rich Si<sub>0.2</sub>Ge<sub>0.8</sub> waveguides on Si<sub>1-x</sub>Ge<sub>x</sub> (x from 0 to 0.79) graded substrates operating in the mid-infrared wavelength range at λ=4.6 μm. Propagation losses as low as (1.5±0.5)dB/cm and (2±0.5)dB/cm were measured for the quasi-TE and quasi-TM polarizations, respectively. A total coupling loss (input/output) of only 10 dB was found for waveguide widths larger than 7 μm due to a good fiber-waveguide mode matching. Near-field optical mode profiles measured at the output waveguide facet allowed us to inspect the optical mode and precisely measure the modal effective area of each waveguide providing a good correlation between experiments and simulations. These results put forward the potential of low-index-contrast Si<sub>1-x</sub>Ge<sub>x</sub> waveguides with high Ge concentration as fundamental blocks for mid-infrared photonic integrated circuits.
ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionali... more ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionality. Here, we demonstrate that it is possible to realize low-loss Ge quantum-well photonic interconnects on Si wafers. We show that Ge-rich Si1–xGex virtual substrates can act as a passive, high-quality optical waveguide on which low-temperature, epitaxial growth of Ge quantum-well devices can be realized. As a proof of concept, the photonic integration of a passive Si0.16Ge0.84 waveguide and two Ge/SiGe multi-quantum-well active devices, an optical modulator and a photodetector was realized to form a photonic interconnect using a single epitaxial growth step. This demonstration confirms that Ge quantum-well interconnects are feasible for low-voltage, broadband optical links integrated on Si chips. Our approach can be extended to any kind of Ge-based optoelectronic device working within telecommunication wavelengths as long as a suitable Ge concentration is selected for the Ge-rich virtual substrate.
Silicon-based photonics is now considered as the photonic platform for the next generation of on-... more Silicon-based photonics is now considered as the photonic platform for the next generation of on-chip communications. However, the development of compact and low power consumption optical modulators is still challenging. Here we report a giant electro-optic effect in Ge/SiGe coupled quantum wells. This promising effect is based on an anomalous quantum-confined Stark effect due to the separate confinement of electrons and holes in the Ge/SiGe coupled quantum wells. This phenomenon can be exploited to strongly enhance optical modulator performance with respect to the standard approaches developed so far in silicon photonics. We have measured a refractive index variation up to 2.3 × 10(-3) under a bias voltage of 1.5 V, with an associated modulation efficiency VπLπ of 0.046 V cm. This demonstration paves the way for the development of efficient and high-speed phase modulators based on the Ge/SiGe material system.
ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionali... more ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionality. Here, we demonstrate that it is possible to realize low-loss Ge quantum-well photonic interconnects on Si wafers. We show that Ge-rich Si1–xGex virtual substrates can act as a passive, high-quality optical waveguide on which low-temperature, epitaxial growth of Ge quantum-well devices can be realized. As a proof of concept, the photonic integration of a passive Si0.16Ge0.84 waveguide and two Ge/SiGe multi-quantum-well active devices, an optical modulator and a photodetector was realized to form a photonic interconnect using a single epitaxial growth step. This demonstration confirms that Ge quantum-well interconnects are feasible for low-voltage, broadband optical links integrated on Si chips. Our approach can be extended to any kind of Ge-based optoelectronic device working within telecommunication wavelengths as long as a suitable Ge concentration is selected for the Ge-rich virtual substrate.
TENCON 2006 - 2006 IEEE Region 10 Conference, 2006
ABSTRACT In this paper, the effect of numbers of bands for acoustic feedback cancellation (AFC) i... more ABSTRACT In this paper, the effect of numbers of bands for acoustic feedback cancellation (AFC) in multi-band compression hearing aids is investigated. Significant improvement in the performance of the AFC system is demonstrated via computer simulations based on different hearing loss characteristics. Moreover, the increment of the dynamic range of hearing when employing multi-band compression hearing aids is shown, as compared to that of conventional hearing aids
We demonstrate low-loss Ge-rich Si<sub>0.2</sub>Ge<sub>0.8</sub> waveguid... more We demonstrate low-loss Ge-rich Si<sub>0.2</sub>Ge<sub>0.8</sub> waveguides on Si<sub>1-x</sub>Ge<sub>x</sub> (x from 0 to 0.79) graded substrates operating in the mid-infrared wavelength range at λ=4.6 μm. Propagation losses as low as (1.5±0.5)dB/cm and (2±0.5)dB/cm were measured for the quasi-TE and quasi-TM polarizations, respectively. A total coupling loss (input/output) of only 10 dB was found for waveguide widths larger than 7 μm due to a good fiber-waveguide mode matching. Near-field optical mode profiles measured at the output waveguide facet allowed us to inspect the optical mode and precisely measure the modal effective area of each waveguide providing a good correlation between experiments and simulations. These results put forward the potential of low-index-contrast Si<sub>1-x</sub>Ge<sub>x</sub> waveguides with high Ge concentration as fundamental blocks for mid-infrared photonic integrated circuits.
ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionali... more ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionality. Here, we demonstrate that it is possible to realize low-loss Ge quantum-well photonic interconnects on Si wafers. We show that Ge-rich Si1–xGex virtual substrates can act as a passive, high-quality optical waveguide on which low-temperature, epitaxial growth of Ge quantum-well devices can be realized. As a proof of concept, the photonic integration of a passive Si0.16Ge0.84 waveguide and two Ge/SiGe multi-quantum-well active devices, an optical modulator and a photodetector was realized to form a photonic interconnect using a single epitaxial growth step. This demonstration confirms that Ge quantum-well interconnects are feasible for low-voltage, broadband optical links integrated on Si chips. Our approach can be extended to any kind of Ge-based optoelectronic device working within telecommunication wavelengths as long as a suitable Ge concentration is selected for the Ge-rich virtual substrate.
Silicon-based photonics is now considered as the photonic platform for the next generation of on-... more Silicon-based photonics is now considered as the photonic platform for the next generation of on-chip communications. However, the development of compact and low power consumption optical modulators is still challenging. Here we report a giant electro-optic effect in Ge/SiGe coupled quantum wells. This promising effect is based on an anomalous quantum-confined Stark effect due to the separate confinement of electrons and holes in the Ge/SiGe coupled quantum wells. This phenomenon can be exploited to strongly enhance optical modulator performance with respect to the standard approaches developed so far in silicon photonics. We have measured a refractive index variation up to 2.3 × 10(-3) under a bias voltage of 1.5 V, with an associated modulation efficiency VπLπ of 0.046 V cm. This demonstration paves the way for the development of efficient and high-speed phase modulators based on the Ge/SiGe material system.
ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionali... more ABSTRACT Monolithic integration of optoelectronics with electronics is a much-desired functionality. Here, we demonstrate that it is possible to realize low-loss Ge quantum-well photonic interconnects on Si wafers. We show that Ge-rich Si1–xGex virtual substrates can act as a passive, high-quality optical waveguide on which low-temperature, epitaxial growth of Ge quantum-well devices can be realized. As a proof of concept, the photonic integration of a passive Si0.16Ge0.84 waveguide and two Ge/SiGe multi-quantum-well active devices, an optical modulator and a photodetector was realized to form a photonic interconnect using a single epitaxial growth step. This demonstration confirms that Ge quantum-well interconnects are feasible for low-voltage, broadband optical links integrated on Si chips. Our approach can be extended to any kind of Ge-based optoelectronic device working within telecommunication wavelengths as long as a suitable Ge concentration is selected for the Ge-rich virtual substrate.
TENCON 2006 - 2006 IEEE Region 10 Conference, 2006
ABSTRACT In this paper, the effect of numbers of bands for acoustic feedback cancellation (AFC) i... more ABSTRACT In this paper, the effect of numbers of bands for acoustic feedback cancellation (AFC) in multi-band compression hearing aids is investigated. Significant improvement in the performance of the AFC system is demonstrated via computer simulations based on different hearing loss characteristics. Moreover, the increment of the dynamic range of hearing when employing multi-band compression hearing aids is shown, as compared to that of conventional hearing aids
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Papers by papichaya chaisakul