Optical bistability on a silicon chip.
TL;DR: It is shown that the optical bistability allows all-optical functionalities, such as switching and memory with microsecond time response and a modulation depth of 10 dB, driven by pump power as low as 45 microW.
Abstract: We demonstrate, for the first time to our knowledge, optical bistability on a highly integrated silicon device, using a 5-microm-radius ring resonator. The strong light-confinement nature of the resonator induces nonlinear optical response with low pump power. We show that the optical bistability allows all-optical functionalities, such as switching and memory with microsecond time response and a modulation depth of 10 dB, driven by pump power as low as 45 microW. Silicon optical bistability relies on a fast thermal nonlinear optical effect presenting a 500-kHz modulation bandwidth.
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TL;DR: An overview of the current state-of-the-art in silicon nanophotonic ring resonators is presented in this paper, where the basic theory of ring resonance is discussed and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes.
Abstract: An overview is presented of the current state-of-the-art in silicon nanophotonic ring resonators. Basic theory of ring resonators is discussed, and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes. Theory is compared to quantitative measurements. Finally, several of the more promising applications of silicon ring resonators are discussed: filters and optical delay lines, label-free biosensors, and active rings for efficient modulators and even light sources.
1,989 citations
TL;DR: The device, which uses two silicon rings 5 micrometers in radius, is passive yet maintains optical nonreciprocity for a broad range of input power levels, and it performs equally well even if the backward input power is higher than the forward input.
Abstract: A passive optical diode effect would be useful for on-chip optical information processing but has been difficult to achieve Using a method based on optical nonlinearity, we demonstrate a forward-backward transmission ratio of up to 28 decibels within telecommunication wavelengths Our device, which uses two silicon rings 5 micrometers in radius, is passive yet maintains optical nonreciprocity for a broad range of input power levels, and it performs equally well even if the backward input power is higher than the forward input The silicon optical diode is ultracompact and is compatible with current complementary metal-oxide semiconductor processing
671 citations
06 May 2012
TL;DR: In this article, the authors demonstrate the exceptionally high third-order nonlinearity of integrated mono-layer graphene-silicon hybrid optoelectronics, enabling ultralow power resonant optical bistability, self-induced regenerative oscillations, and coherent four-wave mixing, all at few femtojoule cavity recirculating energies.
Abstract: We demonstrate the exceptionally-high third-order nonlinearity of integrated mono-layer graphene-silicon hybrid optoelectronics, enabling ultralow power resonant optical bistability, self-induced regenerative oscillations, and coherent four-wave mixing, all at few femto-joule cavity recirculating energies.
571 citations
TL;DR: This work reports the direct detection and exploitation of transverse optical forces in an integrated silicon photonic circuit through an embedded nanomechanical resonator, which enables all-optical operation of nanitechanical systems on a CMOS (complementary metal-oxide-semiconductor)-compatible platform, with substantial bandwidth and design flexibility compared to conventional electrical-based schemes.
Abstract: The force exerted by photons is of fundamental importance in light-matter interactions. For example, in free space, optical tweezers have been widely used to manipulate atoms and microscale dielectric particles. This optical force is expected to be greatly enhanced in integrated photonic circuits in which light is highly concentrated at the nanoscale. Harnessing the optical force on a semiconductor chip will allow solid state devices, such as electromechanical systems, to operate under new physical principles. Indeed, recent experiments have elucidated the radiation forces of light in high-finesse optical microcavities, but the large footprint of these devices ultimately prevents scaling down to nanoscale dimensions. Recent theoretical work has predicted that a transverse optical force can be generated and used directly for electromechanical actuation without the need for a high-finesse cavity. However, on-chip exploitation of this force has been a significant challenge, primarily owing to the lack of efficient nanoscale mechanical transducers in the photonics domain. Here we report the direct detection and exploitation of transverse optical forces in an integrated silicon photonic circuit through an embedded nanomechanical resonator. The nanomechanical device, a free-standing waveguide, is driven by the optical force and read out through evanescent coupling of the guided light to the dielectric substrate. This new optical force enables all-optical operation of nanomechanical systems on a CMOS (complementary metal-oxide-semiconductor)-compatible platform, with substantial bandwidth and design flexibility compared to conventional electrical-based schemes.
557 citations
TL;DR: Measurements indicate that optical loss in these high-Q microresonators is limited not by surface roughness, but rather by surface state absorption and bulk free-carrier absorption.
Abstract: Using a combination of resist reflow to form a highly circular etch mask pattern and a low-damage plasma dry etch, high-quality-factor silicon optical microdisk resonators are fabricated out of silicon-on-insulator (SOI) wafers. Quality factors as high as Q = 5×10^6 are measured in these microresonators, corresponding to a propagation loss coefficient as small as α ~ 0.1 dB/cm. The different optical loss mechanisms are identified through a study of the total optical loss, mode coupling, and thermally-induced optical bistability as a function of microdisk radius (5-30 µm). These measurements indicate that optical loss in these high-Q microresonators is limited not by surface roughness, but rather by surface state absorption and bulk free-carrier absorption.
524 citations
References
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TL;DR: An approach based on a metal–oxide–semiconductor (MOS) capacitor structure embedded in a silicon waveguide that can produce high-speed optical phase modulation is described and an all-silicon optical modulator with a modulation bandwidth exceeding 1 GHz is demonstrated.
Abstract: Silicon has long been the optimal material for electronics, but it is only relatively recently that it has been considered as a material option for photonics1. One of the key limitations for using silicon as a photonic material has been the relatively low speed of silicon optical modulators compared to those fabricated from III–V semiconductor compounds2,3,4,5,6 and/or electro-optic materials such as lithium niobate7,8,9. To date, the fastest silicon-waveguide-based optical modulator that has been demonstrated experimentally has a modulation frequency of only ∼20 MHz (refs 10, 11), although it has been predicted theoretically that a ∼1-GHz modulation frequency might be achievable in some device structures12,13. Here we describe an approach based on a metal–oxide–semiconductor (MOS) capacitor structure embedded in a silicon waveguide that can produce high-speed optical phase modulation: we demonstrate an all-silicon optical modulator with a modulation bandwidth exceeding 1 GHz. As this technology is compatible with conventional complementary MOS (CMOS) processing, monolithic integration of the silicon modulator with advanced electronics on a single silicon substrate becomes possible.
1,612 citations
1,361 citations
"Optical bistability on a silicon ch..." refers background or methods in this paper
...The resonance shift strongly depends on the circulating optical power inside the ring, which in turn strongly depends on the wavelength detuning between the optical source and the shifted resonance; the combined effect of these interrelated mechanisms leads to the bistability curve.(5) Figure 3 shows the measured clockwise hysteresis loop, which evidences a strong optical bistability effect(5); the insets show where the pump wavelength is located relative to the resonance for three distinct positions in the hysteresis loop....
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...The most direct application of optical bistability is in all-optical memory.(5) To demonstrate this functionality, we show in Fig....
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...Optical bistability can be employed to allow all-optical functionalities, such as logic functions, modulation, switching, and memory(5); it has been achieved in compound semiconductor materials with strong nonlinear optical properties.(5) – 7 One can achieve optical bistability on Si by exploiting its thermal nonlinear optical effect,(5) because of its large thermo-optic coefficient ≠n ≠T 1....
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...8); however, it has been demonstrated only in large structures with high pump powers.(5) Here we demonstrate optical bistability on a compact micrometer-size Si integrated structure using input optical powers around 1 mW....
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TL;DR: It is shown that the micrometer-long silicon-on-insulator-based nanotaper coupler is able to efficiently convert both the mode field profile and the effective index, with a total length as short as 40 microm, during compact mode conversion between a fiber and a submicrometer waveguide.
Abstract: We propose and demonstrate an efficient coupler for compact mode conversion between a fiber and a submicrometer waveguide. The coupler is composed of high-index-contrast materials and is based on a short taper with a nanometer-sized tip. We show that the micrometer-long silicon-on-insulator-based nanotaper coupler is able to efficiently convert both the mode field profile and the effective index, with a total length as short as 40 microm. We measure an enhancement of the coupling efficiency between an optical fiber and a waveguide by 1 order of magnitude due to the coupler.
994 citations
TL;DR: In this article, the two-photon absorption coefficient and Kerr coefficient of bulk crystalline silicon are determined near the telecommunication wavelengths of 1.3 and 1.55 μm using femtosecond pulses and a balanced Z-scan technique.
Abstract: The two-photon absorption coefficient and Kerr coefficient of bulk crystalline silicon are determined near the telecommunication wavelengths of 1.3 and 1.55 μm using femtosecond pulses and a balanced Z-scan technique. A phase shift sensitivity of the order of 1 mrad is achieved, enabling the accurate measurement of third-order nonlinear coefficients at fluences smaller than 100 μJ/cm2. From the two-photon absorption coefficient (β∼0.8 cm/GW) and the Kerr coefficient (n2∼4×10−14 cm2/W) at a wavelength λ=1.54 μm, a value F∼0.35 for the nonlinear figure of merit for all-optical switching is determined.
666 citations