Photonic switching devices based on semiconductor nanostructures (Topical Review) (original) (raw)
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Ultrafast, Energy-Efficient Photonic Switches Based on Semiconductor Nanostructures
Asia Communications and Photonics Conference 2013, 2013
This paper discusses fundamental limits in photonic switching devices taking into account of the material's optical nonlinearity as well as optical field enhancement within the device structures. Quantum dot materials in corporation with optical cavity structures are expected to be a powerful combination for ultrafast, energy-efficient photonic switches. Recent demonstration of fJ/cm 2 class switching in QD-based vertical cavity structure is described.
Quantum dot switches : towards nanoscale power-efficient all-optical signal processing
Chao-Yuan Jin, Mark Hopkinson, Osamu Kojima, Takashi Kita, Kouichi Akahane and Osamu Wada, 2012
Photonic devices employing semiconductor quantum dots (QDs) are anticipated to play an important role within power-efficient optical networks. In this chapter, we consider the prospects for signal processing using all-optical QD switches. Vertical cavity structures have been developed to enhance the light-QD interaction and accordingly the optical nonlinearity of QDs which leads to low energy consumption. Such structures show great potential for the realization of power-efficient, polarization-insensitive and micrometer-size switching devices for future photonic signal processing systems.
Photonic switching in III/V nanostructures
2004
95 List of publications 99 Curriculum Vitae 101 IX X Switching in optical communication 1 Chapter 1 Switching in optical communication " Light brings us the news of the Universe" Sir William Bragg 1.1 Introduction Glass fibers are known from the time of Roman civilization. The history of modern fiber optics communication, however, starts with two Nature papers [1], one by the Dutch scientist Abraham van Heel and the other by Harold Hopkins and Narinder Kapani. In these two papers, optical fiber contains a transparent layer of low refractive index that confines the light and protects the surface of the fiber from contamination. These two properties make the fiber capable for transmitting optical signals with low loss. After the invention of semiconductor lasers, the optical communication field progressed rapidly. In 1961, Bernard et.al [2] predicted laser emission from direct inter-band transitions in InAs like semiconductors. In 1962, Hall et.al observed coherent light emission from a GaAs p-n junction. In 1963 Alferov patented his historic invention of semiconductor heterojunction lasers. He first observed lasing in an AlGaAs-GaAs double heterostructure [3]. In 1970 Kapron [4] demonstrated the first glass optical fiber for the low-loss (20 dB/km) transmission of signals in the 1.5 µm wavelength region. In 1986 Kanamori
Chao-Yuan Jin, Osamu Kojima, Tomoya Inoue, Takashi Kita, Osamu Wada, Fellow, IEEE, Mark Hopkinson, and Kouichi Akahane, 2010
We propose an all-optical switch based on self- assembled InAs/GaAs quantum dots (QDs) within a vertical cavity. Two essential aspects of this novel device have been investigated, which includes the QD/cavity nonlinearity with appropriately designed mirrors and the intersubband carrier dynamics inside QDs. Vertical-reflection-type switches have been fabricated with an asymmetric cavity that consists of 12 periods of GaAs/Al0.8Ga0.2As for the front mirror and 25 periods for the back mirror. All-optical switching via the QD excited states has been achieved with a time constant down to 23 ps, wavelength tunability over 30 nm, and ultralow power consumption less than 1 fJ/µm2. These results demonstrate that QDs within a vertical cavity have great advantages to realize low-power- consumption polarization-insensitive micrometer-sized switching devices for the future optical communication and signal process- ing systems.
All-optical switch using InAs quantum dots in a vertical cavity
C. Y. Jin, O. Kojima, T. Inoue, S. Ohta, T. Kita, O. Wada, M. Hopkinson, and K. Akahane, 2010
We have investigated at the first time an all-optical switch using self-assembled InAs/GaAs quantum dots (QDs) within a vertical cavity structure. The optical nonlinearity of the QD switch has been optimized by an asymmetric cavity to achieve the maximum differential reflectivity. Optical switching via QD excited states exhibits a fast decay with a time constant down to 23 ps and a wavelength tunability over 30 nm. By compared to the theoretical design, the absorption strength of QD layers within the cavity has been determined.
ALL-OPTICAL SWITCHES BASED ON GaAs/AlGaAs QUANTUM DOTS VERTICAL CAVITY
Journal of Nonlinear Optical Physics & Materials, 2011
In this paper, we present an all-optical switch based on self-assembled GaAs/AlAs quantum dots (QDs) within a vertical cavity. Two essential aspects of this novel device have been investigated, which includes the QD/cavity nonlinearity with appropriately designed mirrors and the intersubband carrier dynamics inside QDs. Verticalreflection-type switches have been investigated with an asymmetric cavity that consists of 12 periods of GaAs/Al 0.8 Ga 0.2 As for the front mirror and 25 periods for the back mirror. The thicknesses of the GaAs and AlGaAs layers are chosen to be 89 and 102 nm, respectively. To give a dot-in-a-well (DWELL) structure, 65nm dimension of Si was deposited within an 20nm AlAs QW. All-optical switching via the QD excited states has been achieved with a time constant down to 750 fs, wavelength tunability over 29.5 nm. These results demonstrate that QDs within a vertical cavity have great advantages to realize low-power consumption polarization-insensitive micrometer-sized switching devices for the future optical communication and signal processing systems
Vertical-geometry all-optical switches based on InAs/GaAs quantum dots in a cavity
C. Y. Jin, O. Kojima, T. Kita, O. Wada, M. Hopkinson, and K. Akahane, 2009
Self-assembled InAs/GaAs quantum dots (QDs) incorporated in an asymmetric GaAs/Al0.8Ga0.2As vertical cavity have been employed as an optical nonlinear medium for reflection-type all-optical switches. Switching time down to 23 ps together with wavelength tuning range over 30 nm have been achieved in this structure. An angle-dependent behavior of the switching time has been observed, which suggests there is a coupling mechanism between the ground and excited states in QDs with different sizes.
C. Y. Jin, O. Kojima, T. Inoue, T. Kita, O. Wadaa, M. Hopkinson, and K. Akahane, 2010
An all-optical switching device has been proposed by using self-assembled InAs/GaAs quantum dots (QDs) within a vertical cavity structure for ultrafast optical communications. This device has several desirable properties, such as the ultra-low power consumption, the micrometre size, and the polarization insensitive operation. Due to the threedimensional confined carrier state and the broad size distribution of self-assembled InAs/GaAs QDs, it is crucial to enhance the interaction between QDs and the cavity with appropriately designed 1D periodic structure. Significant QD/cavity nonlinearity is theoretically observed by increasing the GaAs/AlAs pair number of the bottom mirror. By this consideration, we have fabricated vertical-reflection type QD switches with 12 periods of GaAs/Al0.8Ga0.2As for the top mirror and 25 periods for the bottom mirror to give an asymmetric vertical cavity. Optical switching via the QD excited state exhibits a fast switching process with a time constant down to 23 ps, confirming that the fast intersubband relaxation of carriers inside QDs is an effective means to speed up the switching process. A technique by changing the light incident angle realizes wavelength tunability over 30 nm for the QD/cavity switch.
Attojoule all-optical switching with a single quantum dot
2011
We experimentally investigate the dynamic nonlinear response of a single quantum dot (QD) strongly coupled to a photonic crystal cavity-waveguide structure. The temporal response is measured by pump-probe excitation where a control pulse propagating through the waveguide is used to create an optical Stark shift on the QD, resulting in a large modification of the cavity reflectivity. This optically induced cavity reflectivity modification switches the propagation direction of a detuned signal pulse. Using this device we demonstrate all-optical switching with only 14 attojoules of control pulse energy. The response time of the switch is measured to be up to 8.4 GHz , which is primarily limited by the cavity-QD interaction strength.
Optical switching in nonlinear photonic crystals lightly doped with nanostructures
Journal of Physics B: Atomic, Molecular and Optical Physics, 2007
A possible switching mechanism has been investigated for nonlinear photonic crystals doped with an ensemble of non-interacting three-level nanoparticles. In this scheme, an intense pump laser field is used to change the refractive index of the nonlinear photonic crystal while a weaker probe field monitors an absorption transition in the nanoparticles. In the absence of the strong laser field the system transmits the probe field when the resonance energy of the nanoparticles lies near the edge of the photonic band gap due to strong coupling between the photonic crystal and the nanoparticles. However, upon application of an intense pump laser field the system becomes absorbing due to a band edge frequency shift that arises due to a nonlinear Kerr effect which changes the refractive index of the crystal. It is anticipated that the optical switching mechanism described in this work can be used to make new types of photonic devices.