Showing papers by "Amnon Yariv published in 2005"
TL;DR: In this paper, the authors combine fiber Bragg grating (FBG) technology with a wet chemical etch-erosion procedure and demonstrate two types of refractive index sensors using singlemode optical fibers.
Abstract: We combine fiber Bragg grating (FBG) technology with a wet chemical etch-erosion procedure and demonstrate two types of refractive index sensors using single-mode optical fibers. The first index sensor device is an etch-eroded single FBG with a radius of 3 μm, which is used to measure the indices of four different liquids. The second index sensor device is an etch-eroded fiber Fabry-Perot interferometer (FFPI) with a radius of ~1.5 μm and is used to measure the refractive indices of isopropyl alcohol solutions of different concentrations. Due to its narrower resonance spectral feature, the FFPI sensor has a higher sensitivity than the FBG sensor and can detect an index variation of 1.4 X 10(-5). Since we can measure the reflection signal, these two types of sensors can be fabricated at the end of a fiber and used as point sensors.
644 citations
TL;DR: In this article, the use of coupled resonator optical waveguides (CROWs) as practical elements to slow and store light pulses is discussed, and the development of a simple solid-state-based technology to slow the propagation of light could prove an important step in the realization of the high-bit-rate communication systems of the future.
Abstract: The development of a simple, solid-state-based technology to slow the propagation of light could prove an important step in the realization of the high-bit-rate communication systems of the future. The use of coupled resonator optical waveguides (CROWs) as practical elements to slow and store light pulses is one possibility.
119 citations
TL;DR: An InGaAsP-InP optical switch geometry based on electrical control of waveguide-resonator coupling is demonstrated, which enables a substantial reduction of the switching power, to a value of 26 mW in comparison with 40 mW for a conventional Mach-Zehnder interferometer switch.
Abstract: An InGaAsP-InP optical switch geometry based on electrical control of waveguide-resonator coupling is demonstrated. Thermooptic tuning of a Mach-Zehnder interferometer integrated with a racetrack resonator is shown to result in switching with ON-OFF contrast up to 18.5 dB. The optical characteristics of this unique design enable a substantial reduction of the switching power, to a value of 26 mW in comparison with 40 mW for a conventional Mach-Zehnder interferometer switch. Modulation response measurements reveal a 3 dB bandwidth of 400 kHz and a rise time of 1.8 µs, comparing favorably with current state-of-the-art thermooptic switches.
116 citations
Posted Content•
TL;DR: In this article, a novel class of circular resonators, based on a radial defect surrounded by Bragg reflectors, is studied in detail, and simple rules for the design and analysis of such structures are derived using a transfer matrix formalism.
Abstract: A novel class of circular resonators, based on a radial defect surrounded by Bragg reflectors, is studied in detail. Simple rules for the design and analysis of such structures are derived using a transfer matrix formalism. Unlike conventional ring resonators, annular Bragg resonators (ABR) are not limited by the total internal reflection condition, and can exhibit both large free spectral ranges and low bend losses. The Bragg reflection mechanism enables the confinement of light within a defect consisting of a low refractive index medium (such as air). Strong atom-photon interaction can be achieved in such a structure, making it a promising candidate for sensing and cavity QED applications. For sensing applications, we show that the ABR structure can possess significantly higher sensitivity when compared to a conventional ring resonator sensor. Lasing action and low threshold levels are demonstrated in ABR lasers at telecommunication wavelengths under pulsed optical pumping at room temperatures. The impact of the intensity and dimensions of the pump-spot on the emitted spectrum is studied in detail.
62 citations
TL;DR: In this article, a novel class of circular resonators, based on a radial defect surrounded by Bragg reflectors, is studied in detail, and simple rules for the design and analysis of such structures are derived using a transfer matrix formalism.
Abstract: A novel class of circular resonators, based on a radial defect surrounded by Bragg reflectors, is studied in detail. Simple rules for the design and analysis of such structures are derived using a transfer matrix formalism. Unlike conventional ring resonators, annular Bragg resonators (ABR) are not limited by the total internal reflection condition and can exhibit both large free spectral ranges and low bend losses. The Bragg reflection mechanism enables the confinement of light within a defect consisting of a low refractive index medium (such as air). Strong atom-photon interaction can be achieved in such a structure, making it a promising candidate for sensing and cavity quantum electrodynamics applications. For sensing applications, we show that the ABR structure can possess significantly higher sensitivity when compared to a conventional ring resonator sensor. Lasing action and low threshold levels are demonstrated in ABR lasers at telecommunication wavelengths under pulsed optical pumping at room temperatures. The impact of the intensity and dimensions of the pump spot on the emitted spectrum is studied in detail.
57 citations
TL;DR: In this article, a radial Bragg reflector was used to demonstrate single-mode lasing at telecommunication wavelengths from a circular nanocavity employing a radial BRF.
Abstract: We demonstrate single-mode lasing at telecommunication wavelengths from a circular nanocavity employing a radial Bragg reflector. Ultrasmall modal volumes and submilliwatt pump thresholds level are observed for lasers with InGaAsP quantum well active membrane. The electromagnetic field is shown to be tightly confined within the 300 nm central pillar of the cavity. The quality factors of the resonator modal fields are estimated to be on the order of a few thousands.microcavity lasers; nanotechnology; distributed Bragg reflector lasers; optical pumping; indium compounds; gallium arsenide; gallium compounds; III-V semiconductors; semiconductor epitaxial layers; quantum well lasers; Q-factor; laser modes
56 citations
TL;DR: In this article, a planar integrated optic reflector based on a microring resonator add-drop wavelength-selective filter is presented. But this design is not suitable for planar optical reflectors.
Abstract: We present a novel design for a compact planar integrated optic reflector based on a microring resonator add-drop wavelength-selective filter. Good agreement is found between the theoretical expectation and the measurements of a device fabricated in optical polymer. The measured device exhibits better than 10-dB rejection for wavelengths resonant with the microring.
55 citations
TL;DR: It is proved the existence of azimuthally polarized, spatial, dark soliton solutions of Maxwell's equations, while exact linearly polarized (2 + 1)D solitons do not exist.
Abstract: Spatial Kerr solitons, typically associated with the standard paraxial nonlinear Schr\"odinger equation, are shown to exist to all nonparaxial orders as exact solutions of Maxwell's equations in the presence of the vectorial Kerr effect. More precisely, we prove the existence of azimuthally polarized, spatial, dark soliton solutions of Maxwell's equations, while exact linearly polarized $(2+1)$D solitons do not exist. Our ab initio approach predicts the existence of dark solitons up to an upper value of the maximum field amplitude, corresponding to a minimum soliton width of about one-fourth of the wavelength.
53 citations
TL;DR: In this article, single-mode lasing at telecommunication wavelengths from a circular nanocavity employing a radial Bragg reflector was demonstrated with InGaAsP quantum well active membrane.
Abstract: We demonstrate single-mode lasing at telecommunication wavelengths from a circular nanocavity employing a radial Bragg reflector. Ultra-small modal volume and Sub milliwatt pump threshold level are observed for lasers with InGaAsP quantum well active membrane. The electromagnetic field is shown to be tightly confined within the 300nm central pillar of the cavity. The quality factors of the resonator modal fields are estimated to be on the order of a few thousands.
37 citations
TL;DR: In this article, it was shown that spatial Kerr solitons, usually obtained in the frame of a nonlinear Schrodinger equation valid in the paraxial approximation, can be found in a generalized form as exact solutions of Maxwell's equations.
Abstract: We prove that spatial Kerr solitons, usually obtained in the frame of a nonlinear Schrodinger equation valid in the paraxial approximation, can be found in a generalized form as exact solutions of Maxwell's equations. In particular, they are shown to exist, both in the bright and dark version, as TM, linearly polarized, exactly integrable one-dimensional solitons and to reduce to the standard paraxial form in the limit of small intensities. In the two-dimensional case, they are shown to exist as azimuthally polarized, circularly symmetric dark solitons. Both one- and two-dimensional dark solitons exhibit a characteristic signature in that their asymptotic intensity cannot exceed a threshold value in correspondence of which their width reaches a minimum sub-wavelength value.
37 citations
TL;DR: A microfluidic variable optical attenuator is fabricate and measure, which consists of an optical waveguide integrated with a micro fluidic channel and obtained a maximum attenuation of 28 dB when the fluid refractive index changes from 1.557 to 1.584.
Abstract: We fabricate and measure a microfluidic variable optical attenuator, which consists of an optical waveguide integrated with a microfluidic channel. An opening is introduced in the upper cladding of the waveguide in order to facilitate the alignment and bonding of the microfluidic channel. By using fluids with different refractive indices, the optical output power is gradually attenuated. We obtain a maximum attenuation of 28 dB when the fluid refractive index changes from 1.557 to 1.584.
TL;DR: A methodology for treating the semiconductor laser as a current-controlled oscillator in an optical phase-lock loop is presented and the formalism is applied to phase demodulation of optical beams, reduction of phase noise by self-homodyning, and phase locking of a semiconductor lasers array.
Abstract: A methodology for treating the semiconductor laser as a current-controlled oscillator in an optical phase-lock loop is presented. The formalism is applied to phase demodulation of optical beams, reduction of phase noise by self-homodyning, and phase locking of a semiconductor laser array.
TL;DR: In this article, an all optically tunable wavelength-selective reflector for planar lightwave technology based on coupled microring resonators is presented, which employs the Vernier effect to demonstrate narrow-band reflection and strong side-lobe suppression.
Abstract: We present an all optically tunable wavelength-selective reflector for planar lightwave technology based on coupled microring resonators. By employing the Vernier effect, we demonstrate narrow-band reflection and strong side-lobe suppression in an optical polymer device fabricated by soft lithography. Wide and simple tuning of the reflection peak using an external control beam is demonstrated.
TL;DR: It is shown that the nonlinear equation that describes nonparaxial Kerr propagation, together with the already reported bright-soliton solutions, admits of (1 + 1)D dark-solicon solutions.
Abstract: We show that the nonlinear equation that describes nonparaxial Kerr propagation, together with the already reported bright-soliton solutions, admits of (1 + 1)D dark-soliton solutions. Unlike their paraxial counterparts, dark solitons can be excited only if their asymptotic normalized intensity u²_infinity is below 3/7; their width becomes constant when u²_infinity approaches this value.
TL;DR: The dependence of the resonator characteristics on the reflector design and parameters is studied in detail and high quality factors and small modal volumes are found for a wide variety of design parameters.
Abstract: We study comprehensively using numerical simulations a new class of resonators, based on a circular photonic crystal reflector. The dependence of the resonator characteristics on the reflector design and parameters is studied in detail. The numerical results are compared to analytic results based on coupled mode theory. High quality factors and small modal volumes are found for a wide variety of design parameters.
TL;DR: By combining a solid-state photoreaction model with the modal solutions of an optical waveguide, the authors simulate the refractive index change due to photobleaching of CLD-1 chromophores in an amorphous polycarbonate microring resonator.
Abstract: By combining a solid-state photoreaction model with the modal solutions of an optical waveguide, we simulate the refractive index change due to the photobleaching of CLD-1 chromophores in an amorphous polycarbonate microring resonator. The simulation agrees well with experimental results. The photobleaching quantum efficiency of the CLD-1 chromophores is determined to be 0.65%. The combined modeling of the electromagnetic wave propagation and photoreaction precisely illustrates the spatial and temporal evolution of the optical properties of the polymer material as manifested in the refractive index and their effects on the modal and physical properties of the optical devices.
04 Apr 2005
TL;DR: In this article, the authors investigate theoretically and experimentally the characteristics, performance and possible applications of coupled resonator optical waveguides (CROWs) and derive analytic expressions for the time delay, usable bandwidth and overall losses in CROW delay lines.
Abstract: We investigate theoretically and experimentally the characteristics, performance and possible applications of coupled resonator optical waveguides (CROWs). The ability to engineer the dispersion properties of a CROW and especially the ability to realize ultra-slow group velocities paves the way for various applications such as delay lines, optical memories and all-optical switching. Simple analytic expressions for the time delay, usable bandwidth and overall losses in CROW delay lines are derived and compared to exact numerical simulation. Good quantitative agreement is found between the theoretical transmission function obtained by transfer matrix formalism and the measurement of a CROW interferometer realized in polymer material.
Proceedings Article•
22 May 2005TL;DR: In this paper, an ultra-sensitive sensor realized in high quality circular semiconductor micro-cavities employing radial Bragg reflectors is demonstrated experimentally, achieving a resolution enhancement by a factor of ten compared to conventional ring resonators.
Abstract: We demonstrate an ultra-sensitive sensor realized in high quality circular semiconductor micro-cavities employing radial Bragg reflectors. Resolution enhancement by a factor of ten, compared to conventional ring resonators, is demonstrated experimentally. ©2005 Optical Society of America OCIS codes: 230.5750 Resonators; 280.3420 Laser sensors
TL;DR: In this article, the fabrication and performance evaluation of a number of all-organic and organic-silicon photonic ring micro-resonator devices are presented, including both electrical and thermal tuning of devices.
Abstract: Organic electro-optic materials offer exceptional processability (both from solution and the gas phase) that permit fabrication of flexible and conformal device structures and the integration of organic materials with a wide range of disparate materials. In addition, organic electro-optical materials have fundamental response times that are in the terahertz region, and useable electro-optic coefficients that are approaching 300 pm/V (at telecommunication wavelengths). In addition to fabrication by traditional lithographic methods, multiple devices on a single wafer have been fabricated by soft and nano-imprint lithography. In this presentation, we review the fabrication and performance evaluation of a number of all-organic and organic-silicon photonic ring microresonator devices. Both electrical and thermal tuning of devices, including both single and multiple ring micro-resonators, are demonstrated.
22 May 2005
TL;DR: In this paper, low-threshold lasing at telecommunications wavelengths from high quality circular semiconductor nanoresonators employing radial Bragg reflector singlemode emission and mode switching are observed at room temperature under optical pumping.
Abstract: We demonstrate low-threshold lasing at telecommunications wavelengths from high quality circular semiconductor nanoresonators employing radial Bragg reflector single-mode emission and mode switching are observed at room temperature under optical pumping.
01 Jan 2005
TL;DR: In this paper, a transverse Bragg resonance (TBR) grating was incorporated into a large-area laser to improve the efficiency compared to traditional index-guided laser.
Abstract: By incorporating a transverse Bragg grating into a large-area laser, the optical modes of the laser can be designed to improve the efficiency compared to traditional index-guided lasers. The resulting transverse Bragg resonance (TBR) waveguide can be designed to have a single lateral mode that is distributed throughout the entire width of the laser for efficient, stable, single lateral mode operation even at high powers. In addition, by designing the dispersion of the TBR modes, we can increase the modal gain at the desired lasing frequencies for further efficiency improvements. We have fabricated electrically pumped, semiconductor TBR lasers in the InP/InGaAsP material system to demonstrate the efficiency gains possible by the incorporation of such a transverse Bragg grating.By incorporating a transverse Bragg grating into a large-area laser, the optical modes of the laser can be designed to improve the efficiency compared to traditional index-guided lasers. The resulting transverse Bragg resonance (TBR) waveguide can be designed to have a single lateral mode that is distributed throughout the entire width of the laser for efficient, stable, single lateral mode operation even at high powers. In addition, by designing the dispersion of the TBR modes, we can increase the modal gain at the desired lasing frequencies for further efficiency improvements. We have fabricated electrically pumped, semiconductor TBR lasers in the InP/InGaAsP material system to demonstrate the efficiency gains possible by the incorporation of such a transverse Bragg grating.
27 May 2005
TL;DR: In this paper, the authors fabricate different bandpass filters based on polymeric waveguide gratings by introducing phase shift defects and integrating with a 3 dB MMI coupler.
Abstract: We fabricate different bandpass filters based on polymeric waveguide gratings by introducing phase shift defects and integrating with a 3 dB MMI coupler. We also use thermo-optic effects to dynamically tune the designed filter
TL;DR: Taking a continuous Bragg grating as a starting point, it is shown that the same grating functionalities can also be realized in any planar waveguide by discretizing it into a series of air holes.
Abstract: In this paper we present an efficient method for designing discrete, nearly-uniform Bragg gratings in generic planar waveguides. Various schemes have already been proposed to design continuous Bragg gratings in optical fibers, but a general scheme for creating their discrete counterpart is still lacking. Taking a continuous Bragg grating as our starting point, we show that the same grating functionalities can also be realized in any planar waveguide by discretizing it into a series of air holes. The relationship between the two gratings is established in terms of grating strength and local grating period.
27 May 2005
TL;DR: In this paper, a reconfigurable wavelength-selective reflector for planar lightwave technology based on coupled microring resonators is proposed and demonstrated in an optical polymer device using the Vernier effect.
Abstract: We propose and demonstrate a novel reconfigurable wavelength-selective reflector for planar lightwave technology based on coupled microring resonators. Narrow-band reflection and strong side-lobe suppression are demonstrated in an optical polymer device using the Vernier effect
10 Apr 2005
TL;DR: In this paper, an InGaAsP/InP optical modulator based on electrical control of waveguide-resonator coupling is demonstrated, which has 18.5 dB contrast, switching power of 29 mW, and 1.8 μs rise time.
Abstract: An InGaAsP/InP optical modulator based on electrical control of waveguide-resonator coupling is demonstrated. Thermooptic switching with 18.5 dB contrast, switching power of 29 mW, and 1.8 μs rise time is measured.