Showing papers by "Amnon Yariv published in 1999"
TL;DR: A laser cavity formed from a single defect in a two-dimensional photonic crystal is demonstrated and pulsed lasing action has been observed at a wavelength of 1.5 micrometers from optically pumped devices with a substrate temperature of 143 kelvin.
Abstract: A laser cavity formed from a single defect in a two-dimensional photonic crystal is demonstrated. The optical microcavity consists of a half wavelength–thick waveguide for vertical confinement and a two-dimensional photonic crystal mirror for lateral localization. A defect in the photonic crystal is introduced to trap photons inside a volume of 2.5 cubic half-wavelengths, approximately 0.03 cubic micrometers. The laser is fabricated in the indium gallium arsenic phosphide material system, and optical gain is provided by strained quantum wells designed for a peak emission wavelength of 1.55 micrometers at room temperature. Pulsed lasing action has been observed at a wavelength of 1.5 micrometers from optically pumped devices with a substrate temperature of 143 kelvin.
2,310 citations
TL;DR: The relations for the dispersion and the group velocity of the photonic band of the CROW's are obtained and it is found that they are solely characterized by coupling factor k(1) .
Abstract: We propose a new type of optical waveguide that consists of a sequence of coupled high- Q resonators. Unlike other types of optical waveguide, waveguiding in the coupled-resonator optical waveguide (CROW) is achieved through weak coupling between otherwise localized high- Q optical cavities. Employing a formalism similar to the tight-binding method in solid-state physics, we obtain the relations for the dispersion and the group velocity of the photonic band of the CROW's and find that they are solely characterized by coupling factor k 1 . We also demonstrate the possibility of highly efficient nonlinear optical frequency conversion and perfect transmission through bends in CROW's.
1,671 citations
26 Jul 1999
TL;DR: In this paper, a new type of optical microcavity using 2D photonic crystals embedded in a half-wavelength thick waveguide was proposed, which enables one to tailor the device for vertical emission or coupling into an in-plane waveguide.
Abstract: We form a new type of optical microcavity using 2D photonic crystals embedded in a half wavelength thick waveguide Modes localized to a single defect in the photonic crystal can be theoretically shown to have small mode volumes The flexibility in design of the photonic crystal enables one to tailor the device for vertical emission or for coupling into an in-plane waveguide The added versatility in being able to etch the laser cavity may also help develop low threshold laser sources in material systems in which high index contrast epitaxial mirrors do not exist
206 citations
TL;DR: In this paper, a general numerical method to calculate the spontaneous emission lifetime in an arbitrary microcavity, using a finite-difference time-domain algorithm, was developed, which is limited only by numerical error and finite reflection at the absorbing boundaries.
Abstract: We developed a general numerical method to calculate the spontaneous emission lifetime in an arbitrary microcavity, using a finite-difference time-domain algorithm. For structures with rotational symmetry we also developed a more efficient but less general algorithm. To simulate an open radiation problem, we use absorbing boundaries to truncate the computational domain. The accuracy of this method is limited only by numerical error and finite reflection at the absorbing boundaries. We compare our result with cases that can be solved analytically and find excellent agreement. Finally, we apply the method to calculate the spontaneous emission lifetime in a slab waveguide and in a dielectric microdisk, respectively.
133 citations
TL;DR: In this article, the authors presented a general method for the /spl beta/ factor calculation in optical microcavities based on the classical model for atomic transitions in a semiconductor active medium, which is used to evolve the electromagnetic fields of the system and calculate the total radiated energy, as well as the energy radiated into the mode of interest.
Abstract: We present a general method for the /spl beta/ factor calculation in optical microcavities. The analysis is based on the classical model for atomic transitions in a semiconductor active medium. The finite-difference time-domain method is used to evolve the electromagnetic fields of the system and calculate the total radiated energy, as well as the energy radiated into the mode of interest. We analyze the microdisk laser and compare our result with the previous theoretical and experimental analyses. We also calculate the /spl beta/ factor of the microcavity based on a two-dimensional (2-D) photonic crystal in an optically thin dielectric slab. From the /spl beta/ calculations, we are able to estimate the coupling to radiation modes in both the microdisk and the 2-D photonic crystal cavity, thereby showing the effectiveness of the photonic crystal in suppressing in-plane radiation modes.
96 citations
TL;DR: In this paper, the authors demonstrate theoretically that stimulated Brillouin scattering (SBS) can induce a phase shift of the optical carrier relative to its sidebands due to the waveguiding effect of optical fiber on the acoustic wave, which results in an increase in the relative intensity noise and degradation of the modulation response of directly modulated lasers after propagation in an optical fiber.
Abstract: Here we demonstrate theoretically that stimulated Brillouin scattering (SBS) can induce a phase shift of the optical carrier relative to its sidebands due to the waveguiding effect of the optical fiber on the acoustic wave. This causes conversion of frequency modulation to intensity modulation, which results in an increase in the relative intensity noise and degradation of the modulation response of directly modulated lasers after propagation in an optical fiber, in agreement with our experimental observations. Suppression of SBS can be achieved at low frequencies and high modulation powers due to the laser adiabatic chirp.
87 citations
TL;DR: In this article, a new expansion for the Jones matrix of a transmission medium is used to describe high-order polarisation dispersion, and a new expression for pulse deformation is derived and confirmed by simulation.
Abstract: A new expansion for the Jones matrix of a transmission medium is used to describe high-order polarisation dispersion. Each term in the expansion is characterised by a pair of principal states and the corresponding dispersion parameters. With these descriptors, a new expression for pulse deformation is derived and confirmed by simulation.
83 citations
Patent•
07 Dec 1999TL;DR: In this paper, a whispering gallery mode device is proposed for optical wave power control, where the power of a chosen resonant wavelength is coupled into the resonator, where it circulates with very low loss, and returns energy to the propagation element, and the propagated power can be varied between substantially full and substantially zero amplitudes.
Abstract: An optical wave power control device and method enables signal control, such as modulation and switching, to be effected within an uninterrupted propagation element, e.g. an optical fiber or planar waveguide. The propagation element is configured such that a portion of its wave guided power encompasses the exterior surface of the element, intercepting the periphery of an adjacent high Q volumetric resonator. Power of a chosen resonant wavelength is coupled into the resonator, where it circulates with very low loss in accordance with the principles of a whispering gallery mode device, and returns energy to the propagation element. By introducing loss within the resonator, the propagated power can be varied between substantially full and substantially zero amplitudes. Loss factors can be maintained such that the resonator is overcoupled, i.e. parasitic losses are less than coupling losses, and a critical coupling condition exists in which a small swing in the control effect causes a disproportionate change in the optical output signal.
53 citations
TL;DR: In this article, a two-dimensional photonic crystal defined hexagonal disk laser which relies on Bragg reflection rather than the total internal reflection as in traditional microdisk lasers is described.
Abstract: A two-dimensional photonic crystal defined hexagonal disk laser which relies on Bragg reflection rather than the total internal reflection as in traditional microdisk lasers is described. The devices are fabricated using a selective etch to form free standing membranes suspended in air. Room temperature lasing at 1650nm for a 150nm thick, ~15μm wide cavity fabricated in InP/GaAsP is demonstrated with pulsed optical pumping.
39 citations
TL;DR: In this paper, an active, photonic band gap-based microcavity emitter in the near infrared was demonstrated, and the spontaneous emission power and spectrum from a micro cavity formed using a two-dimensional photonic gap structure in a half wavelength thick slab waveguide was measured.
Abstract: An active, photonic band gap-based microcavity emitter in the near infrared is demonstrated. We present direct measurement of the spontaneous emission power and spectrum from a microcavity formed using a two-dimensional photonic band gap structure in a half wavelength thick slab waveguide. The appearance of cavity resonance peaks in the spectrum correspond to the photonic band gap energy. For detuned band gaps, no resonances are observed. For devices with correctly tuned band gaps, a two-time enhancement of the extraction efficiency was demonstrated compared to detuned band gaps and unpatterned material.
39 citations
TL;DR: In this article, an analysis of multimode waveguides where several modes are coupled via quasiperiodic perturbations is presented, and the supermodes (or eigenmodes) of the structure are derived and orthonormality considerations are discussed.
Abstract: An analysis of multimode waveguides where several modes are coupled via quasiperiodic perturbations is presented. The supermodes (or eigenmodes) of the structure are derived and orthonormality considerations are discussed. In addition, a new type of mode converter between copropagating modes is proposed, where mode conversion is mediated by a backward propagating mode. Adiabatic and nonadiabatic coupling coefficients are considered and the supermode formalism is used to conveniently describe the mode of operation of the device.
14 Jun 1999
TL;DR: The Vertical Cavity Surface Emitting Laser (VCSEL) as mentioned in this paper was the first device to shrink the optical mode to sizes on the order of the wavelength of light, and was used for spontaneous emission control.
Abstract: With the maturation of crystal growth along with the nanofabrication of semiconductors there has been strong interest in creating optical microcavities for spontaneous emission control. The Vertical Cavity Surface Emitting Laser (VCSEL) was the first device to shrink the optical mode to sizes on the order of the wavelength of light[l].
TL;DR: In this paper, the polarisation dependence of photowritten gratings in ion-exchanged glass channel waveguides is measured and discussed, and it is shown that these gratings have a rejection dip of almost 20 dB.
Abstract: Gratings are photowritten in ion-exchanged glass channel waveguides. The transmission of these waveguides shows a rejection dip of almost 20 dB. The polarisation dependence of these waveguide gratings is measured and discussed.
TL;DR: In this article, a holographic characterization technique is developed in accordance with a general photopolymerization model, which allows detailed quantification of the chemical parameters, including their variation from the Trommsdorff effect.
Abstract: A holographic characterization technique is developed in accordance with a general photopolymerization model The technique allows detailed quantification of the chemical parameters, including their variation from the Trommsdorff effect The holographic procedure is especially suited for studying the diffusion of the chemical reactants
Patent•
04 Jun 1999TL;DR: In this article, the mediating region of an optical waveguide has at least two coupling regions (i.e., coupling region (i) couples an output mode and mediating mode, and second region (ii) couples mediating and an input mode that copropagates with the output mode).
Abstract: Optical waveguide devices (100) based on optical coupling of different modes (110, 130) by using a mediating mode (120). Such waveguide devices (100) generally have at least to coupling regions (104, 106). The first coupling region (104) couples an output mode and the mediating mode, and the second one (106) couples the mediating mode and an input mode that copropagates with the output mode. Under proper conditions, the energy in the input mode can be completely transferred to the output mode, without energy loss to the mediating mode (120).
TL;DR: In this article, the power dependence of the linewidth enhancement factor is shown to explain the saturation of the laser linwidth at high optical powers, and the influence of the intraband damping mechanisms, the DFB structure and the carrier transport and carrier capture into the QWs on the laser chirp.
Abstract: Measurements of relative intensity noise and modulation response, before and after propagation in optical fiber, of the output field of multiquantum-well distributed-feedback (MQW-DFB) lasers are used to determine the influence of the intraband damping mechanisms, the DFB structure and the carrier transport and carrier capture into the QWs on the laser chirp. The power dependence of the linewidth enhancement factor is shown to explain the saturation of the laser linewidth at high optical powers.
TL;DR: In this article, a three-dimensional index variation grating in bulk BGG31 glass written using neither hydrogen loading nor germanium doping is demonstrated, which is useful for fabricating ion-exchanged waveguides, and its photosensitivity to ultraviolet radiation at 248nm has not been previously explored.
Abstract: A three-dimensional index variation grating in bulk BGG31 glass written using neither hydrogen loading nor germanium doping is demonstrated. This material is useful for fabricating ion-exchanged waveguides, and its photosensitivity to ultraviolet (UV) radiation at 248nm has not been previously explored. Intensity measurements of the Bragg diffracted spots indicated a maximum index variation (Delta n) of similar to 4 x 10(-5).
TL;DR: In this paper, the authors considered the self-consistent pulses which can propagate in a periodic fiber with alternating linear (β2≠0, n2=0) and nonlinear (β 2 = 0, n 2 ≥ 0) sections.
Abstract: We consider the self-consistent pulses which can propagate in a periodic fiber with alternating linear (β2≠0, n2=0) and nonlinear (β2=0, n2≠0) sections. The repeating breathing eigen pulse of the wave guide is derived.
08 Nov 1999
TL;DR: In this paper, a microcavity laser using two-dimensional photonic crystals embedded in a half wavelength thick waveguide was constructed, and the defect laser cavities were formed in the InGaAsP material system in order to reduce the nonradiative surface recombination rate.
Abstract: We form a microcavity laser using two-dimensional photonic crystals embedded in a half wavelength thick waveguide. Modes localized to a single defect in the photonic crystal can be theoretically shown to have mode volumes as small 2(/spl lambda//2n)/sup 3/ and near unity spontaneous emission coupling factors. The flexibility in design of the photonic crystal enables one to tailor the device for vertical emission or for coupling into an in-plane waveguide. These type of devices may be useful for high density, low threshold optical sources in compact optical systems. The added versatility in being able to etch the laser cavity may also help develop low threshold laser sources in material systems in which high index contrast epitaxial mirrors do not exist. The defect laser cavities were formed in the InGaAsP material system in order to reduce the non-radiative surface recombination rate. The active region consists of four quantum wells (QW) designed for 1.55 /spl mu/m peak emission at room temperature.
28 May 1999
TL;DR: In this paper, optically pumped two-dimensional photonic crystal defect InGaAsP MQW lasers at 1.5 /spl mu/m were demonstrated in microcavities as small as 2(/spl lambda//2n)/sup 3.
Abstract: We have demonstrated optically pumped two-dimensional photonic crystal defect InGaAsP MQW lasers at 1.5 /spl mu/m. Pulsed lasing action at 143 K has been obtained in microcavities as small as 2(/spl lambda//2n)/sup 3/.
26 Jul 1999
TL;DR: In this article, the specific source laser characteristics which determine the excess link noise are discussed as well as how they can be accurately measured, and the authors discuss how to determine this excess noise and how to accurately measure it.
Abstract: With the recent advent of erbium-doped fiber amplifiers, CATV networks are now utilizing 1550 nm technologies to achieve high fidelity transmission over long fiber links. Although the lower fiber attenuation at 1550 nm serves to improve the network's power budget, the non-zero dispersion frequently necessitates the use of external modulation to avoid dispersion induced distortions. Fiber dispersion, when combined with certain laser characteristics, can also lead to excess link noise. In this paper, we discuss the specific source laser characteristics which determine this excess noise as well as how they can be accurately measured.
01 Jan 1999
TL;DR: In this article, an analysis of multimode waveguides where several modes are coupled via quasiperiodic perturbations is presented, and the supermodes (or eigenmodes) of the structure are derived and orthonormality considerations are discussed.
Abstract: An analysis of multimode waveguides where several modes are coupled via quasiperiodic perturbations is presented. The supermodes (or eigenmodes) of the structure are derived and orthonormality considerations are discussed. In addition, a new type of mode converter between copropagating modes is proposed, where mode conversion is mediated by a backward- propagating mode. Adiabatic and nonadiabatic coupling coeffi- cients are considered and the supermode formalism is used to conveniently describe the mode of operation of the device.
23 Sep 1999
TL;DR: The performance of a lightwave communication system is often affected by the laser's relative intensity noise (RIN), which can be a critical factor in determining the system signal-to-noise ratio.
Abstract: The performance of a lightwave communication system is often affected by the laser’s relative intensity noise (RIN), which can be a critical factor in determining the system signal-to-noise ratio.
24 May 1999
TL;DR: In this article, the quantum noise limits of a semiconductor laser with dispersive loss were examined theoretically and experimentally, and they demonstrated almost 6 orders of magnitude reduction in the linewidth to a 44 Hz level, and 1.9 dB amplitude noise squeezing below the standard quantum noise limit.
Abstract: The quantum noise limits of a semiconductor laser with dispersive loss are examined theoretically and experimentally. Using optical feedback from Cs vapor as a dispersive loss element we demonstrate almost 6 orders of magnitude reduction in the linewidth, to a 44 Hz level, and 1.9 dB amplitude noise squeezing below the standard quantum noise limit.
28 May 1999
TL;DR: In this article, the spectral density of intensity variations after propagation in a fiber exhibiting only lowest-order group velocity dispersion has an exact solution in terms of the 4th order correlation function of the input field envelope.
Abstract: Summary form only given. The conversion of laser phase noise to intensity noise by the effect of group velocity dispersion (GVD) in a single-mode optical fiber is well-known. In fiber links such as analog "supertrunk" CATV links and digital dispersion supported transmission (DST) links which span moderate to long distances at 1.55 /spl mu/m, this effect leads to requirements for narrow source laser linewidths. Previous authors have addressed this problem theoretically using a variety of approximate methods which are generally sufficient for consideration of the above applications. None of these models, however, can account conceptually for the large phase variations which inevitably result from phase diffusion, i.e. the "random walk" of the laser phase. Thus for large linewidths or long fiber lengths they eventually will fail. We have found that the spectral density of intensity variations after propagation in a fiber exhibiting only lowest-order group velocity dispersion has an exact solution in terms of the 4th order correlation function of the input field envelope.
23 Sep 1999
TL;DR: The development of fiber Bragg gratings has enabled fabrication of a variety of different Bragg grating devices that were not possible previously, such as dispersion compensators and band-rejection filters.
Abstract: The development of fiber Bragg gratings has enabled fabrication of a variety of different Bragg grating devices that were not possible previously, such as dispersion compensators and band-rejection filters.