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Showing papers in "Optics Express in 2004"


Journal ArticleDOI
TL;DR: The transfer of information encoded as orbital angular momentum states of a light beam is demonstrated, which is resistant to eavesdropping and gives an experimental insight into the effects of aperturing and misalignment of the beam on the OAM measurement and demonstrates the uncertainty relationship for OAM.
Abstract: We demonstrate the transfer of information encoded as orbital angular momentum (OAM) states of a light beam. The transmitter and receiver units are based on spatial light modulators, which prepare or measure a laser beam in one of eight pure OAM states. We show that the information encoded in this way is resistant to eavesdropping in the sense that any attempt to sample the beam away from its axis will be subject to an angular restriction and a lateral offset, both of which result in inherent uncertainty in the measurement. This gives an experimental insight into the effects of aperturing and misalignment of the beam on the OAMmeasurement and demonstrates the uncertainty relationship for OAM.

2,230 citations


Journal ArticleDOI
TL;DR: High-resolution spectral domain OCT is shown to provide a ~100x increase in imaging speed when compared to ultrahigh-resolution time domain OCT, and a general technique for automatic numerical dispersion compensation is presented, which is applicable to spectral domain as well as swept source embodiments of Fourier domain OCT.
Abstract: Ultrahigh-resolution optical coherence tomography uses broadband light sources to achieve axial image resolutions on the few micron scale. Fourier domain detection methods enable more than an order of magnitude increase in imaging speed and sensitivity, thus overcoming the sensitivity limitations inherent in ultrahigh-resolution OCT using standard time domain detection. Fourier domain methods also provide direct access to the spectrum of the optical signal. This enables automatic numerical dispersion compensation, a key factor in achieving ultrahigh image resolutions. We present ultrahigh-resolution, high-speed Fourier domain OCT imaging with an axial resolution of 2.1 µm in tissue and 16,000 axial scans per second at 1024 pixels per axial scan. Ultrahigh-resolution spectral domain OCT is shown to provide a ~100x increase in imaging speed when compared to ultrahigh-resolution time domain OCT. In vivo imaging of the human retina is demonstrated. We also present a general technique for automatic numerical dispersion compensation, which is applicable to spectral domain as well as swept source embodiments of Fourier domain OCT.

1,168 citations


Journal ArticleDOI
Yurii A. Vlasov1, Sharee J. McNab1
TL;DR: The fabrication and accurate measurement of propagation and bending losses in single-mode silicon waveguides with submicron dimensions fabricated on silicon-on-insulator wafers with record low numbers can be used as a benchmark for further development of silicon microphotonic components and circuits.
Abstract: We report the fabrication and accurate measurement of propagation and bending losses in single-mode silicon waveguides with submicron dimensions fabricated on silicon-on-insulator wafers. Owing to the small sidewall surface roughness achieved by processing on a standard 200mm CMOS fabrication line, minimal propagation losses of 3.6+/-0.1dB/cm for the TE polarization were measured at the telecommunications wavelength of 1.5microm. Losses per 90 masculine bend are measured to be 0.086+/-0.005dB for a bending radius of 1microm and as low as 0.013+/-0.005dB for a bend radius of 2microm. These record low numbers can be used as a benchmark for further development of silicon microphotonic components and circuits.

999 citations


Journal ArticleDOI
TL;DR: A highly-efficient cladding-pumped ytterbium-doped fiber laser generating 1.36 kW of continuous-wave output power at 1.1 mum with 83% slope efficiency and near diffraction-limited beam quality is demonstrated.
Abstract: We have demonstrated a highly-efficient cladding-pumped ytterbium-doped fiber laser generating 1.36 kW of continuous-wave output power at 1.1 µm with 83% slope efficiency and near diffraction-limited beam quality. The laser was end-pumped through both fiber ends and showed no evidence of roll-over even at the highest output power, which was limited only by available pump power.

887 citations


Journal ArticleDOI
TL;DR: The demonstration of the first silicon Raman laser using a silicon waveguide as the gain medium and has a clear threshold at 9 W peak pump pulse power and a slope efficiency of 8.5%.
Abstract: We report the demonstration of the first silicon Raman laser. Experimentally, pulsed Raman laser emission at 1675 nm with 25 MHz repetition rate is demonstrated using a silicon waveguide as the gain medium. The laser has a clear threshold at 9 W peak pump pulse power and a slope efficiency of 8.5%.

823 citations


Journal ArticleDOI
Qiwen Zhan1
TL;DR: Numerical studies show that optical tweezers using radial polarization can stably trap metallic particles in 3-dimension due to the spatial separation of the gradient force and scattering/absorption forces.
Abstract: Metallic particles are generally considered difficult to trap due to strong scattering and absorption forces. In this paper, numerical studies show that optical tweezers using radial polarization can stably trap metallic particles in 3-dimension. The extremely strong axial component of a highly focused radially polarized beam provides a large gradient force. Meanwhile, this strong axial field component does not contribute to the Poynting vector along the optical axis. Consequently, it does not create axial scattering/absorption forces. Owing to the spatial separation of the gradient force and scattering/absorption forces, a stable 3-D optical trap for metallic particles can be formed.

747 citations


Journal ArticleDOI
TL;DR: Not involving evanescent fields and not requiring mechanical scanning, photonic nanojets may provide a new means to detect and image nanoparticles of size well below the diffraction limit and yield a potential novel ultramicroscopy technique using visible light for detecting proteins, viral particles, and even single molecules.
Abstract: We report what we believe to be the first evidence of localized nanoscale photonic jets generated at the shadow-side surfaces of micronscale, circular dielectric cylinders illuminated by a plane wave These photonic nanojets have waists smaller than the diffraction limit and propagate over several optical wavelengths without significant diffraction We have found that such nanojets can enhance the backscattering of visible light by nanometer-scale dielectric particles located within the nanojets by several orders of magnitude Not involving evanescent fields and not requiring mechanical scanning, photonic nanojets may provide a new means to detect and image nanoparticles of size well below the diffraction limit This could yield a potential novel ultramicroscopy technique using visible light for detecting proteins, viral particles, and even single molecules; and monitoring molecular synthesis and aggregation processes of importance in many areas of biology, chemistry, material sciences, and tissue engineering

733 citations


Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate a self-stable equilibrium solution for a pump-microcavity system, where intensity and wavelength perturbations cause a small thermal resonant-drift that is enough to compensate for the perturbation.
Abstract: As stability and continuous operation are important for almost any use of a microcavity, we demonstrate here experimentally and theoretically a self-stable equilibrium solution for a pump-microcavity system. In this stable equilibrium, intensity- and wavelength-perturbations cause a small thermal resonant-drift that is enough to compensate for the perturbation (noises); consequently the cavity stays warm and loaded as perturbations are self compensated. We also compare here, our theoretical prediction for the thermal line broadening (and for the wavelength hysteretic response) to experimental results.

694 citations


Journal ArticleDOI
TL;DR: 3-dimensional data sets were collected in 11 and 13 seconds for the macula and optic nerve head respectively and are presented to demonstrate the potential clinical applications of SD-OCT in ophthalmology.
Abstract: An ultra-high-speed spectral-domain optical coherence tomography system (SD-OCT) was developed for imaging the human retina and optic nerve in vivo at a sustained depth profile (A-line) acquisition speed of 29 kHz. The axial resolution was 6 µm in tissue and the system had shot-noise-limited performance with a maximum sensitivity of 98.4 dB. 3-dimensional data sets were collected in 11 and 13 seconds for the macula and optic nerve head respectively and are presented to demonstrate the potential clinical applications of SD-OCT in ophthalmology. Additionally, a 3-D volume of the optic nerve head was constructed from the acquired data and the retinal vascular network was visualized.

687 citations


Journal ArticleDOI
TL;DR: Air-clad subwavelength-diameter wires have interesting properties such as tight-confinement ability, enhanced evanescent fields and large waveguide dispersions that are very promising for developing future microphotonic devices with subwa wavelength-width structures.
Abstract: Single-mode optical wave guiding properties of silica and silicon subwavelength-diameter wires are studied with exact solutions of Maxwell's equations. Single mode conditions, modal fields, power distribution, group velocities and waveguide dispersions are studied. It shows that air-clad subwavelength-diameter wires have interesting properties such as tight-confinement ability, enhanced evanescent fields and large waveguide dispersions that are very promising for developing future microphotonic devices with subwavelength-width structures.

682 citations


Journal ArticleDOI
TL;DR: It is shown that very-long ultra-low-loss tapers can in fact be produced using a conventional fiber taper rig incorporating a simple burner configuration, and the optical losses achieved are one order of magnitude lower than losses previously reported in the literature for tapers of a similar size.
Abstract: Optical fiber tapers with a waist size larger than 1microm are commonplace in telecommunications and sensor applications. However the fabrication of low-loss optical fiber tapers with subwavelength diameters was previously thought to be impractical due to difficulties associated with control of the surface roughness and diameter uniformity. In this paper we show that very-long ultra-low-loss tapers can in fact be produced using a conventional fiber taper rig incorporating a simple burner configuration. For single-mode operation, the optical losses we achieve at 1.55microm are one order of magnitude lower than losses previously reported in the literature for tapers of a similar size. SEM images confirm excellent taper uniformity. We believe that these low-loss structures should pave the way to a whole range of fiber nanodevices.

Journal ArticleDOI
TL;DR: With this new system, two layers at the location of the retinal pigmented epithelium seem to be present, as well as small features in the inner and outer plexiform layers, which are believed to be small blood vessels.
Abstract: We present the first ultrahigh-resolution optical coherence tomography (OCT) structural intensity images and movies of the human retina in vivo at 29.3 frames per second with 500 A-lines per frame. Data was acquired at a continuous rate of 29,300 spectra per second with a 98% duty cycle. Two consecutive spectra were coherently summed to improve sensitivity, resulting in an effective rate of 14,600 A-lines per second at an effective integration time of 68 micros. The turn-key source was a combination of two super luminescent diodes with a combined spectral width of more than 150 nm providing 4.5 mW of power. The spectrometer of the spectraldomain OCT (SD-OCT) setup was centered around 885 nm with a bandwidth of 145 nm. The effective bandwidth in the eye was limited to approximately 100 nm due to increased absorption of wavelengths above 920 nm in the vitreous. Comparing the performance of our ultrahighresolution SD-OCT system with a conventional high-resolution time domain OCT system, the A-line rate of the spectral-domain OCT system was 59 times higher at a 5.4 dB lower sensitivity. With use of a software based dispersion compensation scheme, coherence length broadening due to dispersion mismatch between sample and reference arms was minimized. The coherence length measured from a mirror in air was equal to 4.0 microm (n= 1). The coherence length determined from the specular reflection of the foveal umbo in vivo in a healthy human eye was equal to 3.5 microm (n = 1.38). With this new system, two layers at the location of the retinal pigmented epithelium seem to be present, as well as small features in the inner and outer plexiform layers, which are believed to be small blood vessels. ?2004 Optical Society of America.

Journal ArticleDOI
TL;DR: In this paper, the transmission is modulated not by coupling to surface plasmon resonance, but by interference of diffracted evanescent waves generated by subwavelength features at the surface.
Abstract: Transmission enhancements of order 1000 have been reported for subwavelength hole arrays in metal films and attributed to surface plasmon (SP) resonance. We show that the properly normalized enhancement factor is consistently less than 7, and that similar enhancements occur in nonmetallic systems that do not support SPs. We present a new model in which the transmission is modulated not by coupling to SPs but by interference of diffracted evanescent waves generated by subwavelength features at the surface, leading to transmission suppression as well as enhancement. This mechanism accounts for the salient optical properties of subwavelength apertures surrounded by periodic surface corrugations.

Journal ArticleDOI
TL;DR: Visualization of intra-retinal layers, especially the inner and outer segment of the photoreceptor layer, obtained by FDOCT was comparable to that, accomplished by ultrahigh resolution time domain OCT, despite an at least 40 times higher data acquisition speed of FD OCT.
Abstract: We present, for the first time, in vivo ultrahigh resolution (~2.5 μm in tissue), high speed (10000 A-scans/second equivalent acquisition rate sustained over 160 A-scans) retinal imaging obtained with Fourier domain (FD) OCT employing a commercially available, compact (500×260mm), broad bandwidth (120 nm at full-width-at-half-maximum centered at 800 nm) Titanium:sapphire laser (Femtosource Integral OCT, Femtolasers Produktions GmbH). Resolution and sampling requirements, dispersion compensation as well as dynamic range for ultrahigh resolution FD OCT are carefully analyzed. In vivo OCT sensitivity performance achieved by ultrahigh resolution FD OCT was similar to that of ultrahigh resolution time domain OCT, although employing only 2–3 times less optical power (~300 μW). Visualization of intra-retinal layers, especially the inner and outer segment of the photoreceptor layer, obtained by FDOCT was comparable to that, accomplished by ultrahigh resolution time domain OCT, despite an at least 40 times higher data acquisition speed of FD OCT.

Journal ArticleDOI
TL;DR: Photonic crystal fibres exhibiting endlessly single-mode operation and dispersion zero in the range 1040 to 1100 nm are demonstrated.
Abstract: Photonic crystal fibres exhibiting endlessly single-mode operation and dispersion zero in the range 1040 to 1100 nm are demonstrated. A sub-ns pump source at 1064 nm generates a parametric output at 732 nm with an efficiency of 35%, or parametric gain of 55 dB at 1315 nm. A broad, flat supercontinuum extending from 500 nm to beyond 1750 nm is also demonstrated using the same pump source.

Journal ArticleDOI
TL;DR: Submicron-diameter tapered fibres and photonic crystal fibre cores, both of which are silica-air waveguides with low dispersion at 532 nm, were made using a conventional tapering process to generate a single-mode supercontinuum broad enough to fill the visible spectrum without spreading far beyond it.
Abstract: Submicron-diameter tapered fibres and photonic crystal fibre cores, both of which are silica-air waveguides with low dispersion at 532 nm, were made using a conventional tapering process. In just cm of either waveguide, ns pulses from a low-power 532-nm microchip laser generated a single-mode supercontinuum broad enough to fill the visible spectrum without spreading far beyond it.

Journal ArticleDOI
TL;DR: Experimental results of 3D image sensing and volume pixel reconstruction are presented to test and verify the performance of the algorithm and the imaging system.
Abstract: We propose a three-dimensional (3D) imaging technique that can sense a 3D scene and computationally reconstruct it as a 3D volumetric image. Sensing of the 3D scene is carried out by obtaining elemental images optically using a pickup microlens array and a detector array. Reconstruction of volume pixels of the scene is accomplished by computationally simulating optical reconstruction according to ray optics. The entire pixels of the recorded elemental images contribute to volumetric reconstruction of the 3D scene. Image display planes at arbitrary distances from the display microlens array are computed and reconstructed by back propagating the elemental images through a computer synthesized pinhole array based on ray optics. We present experimental results of 3D image sensing and volume pixel reconstruction to test and verify the performance of the algorithm and the imaging system. The volume pixel values can be used for 3D image surface reconstruction.

Journal ArticleDOI
TL;DR: The design, fabrication, and measurement of photonic-band-gap waveguides, resonators and their coupled elements in two-dimensional photonic crystal (PhC) slabs have been investigated and a large group delay is observed by time-domain measurement.
Abstract: The design, fabrication, and measurement of photonic-band-gap (PBG) waveguides, resonators and their coupled elements in two-dimensional photonic crystal (PhC) slabs have been investigated. We have studied various loss mechanisms in PBG waveguides and have achieved a very low propagation loss (~1 dB/mm). For these waveguides, we have observed a large group delay (>100 ps) by time-domain measurement. As regards PBG resonators, we realize very high-Q and small volume resonators in PhC slabs by appropriate design. Finally, we demonstrate various forms of coupled elements of waveguides and resonators: 2-port resonant-tunneling transmission devices, 4-port channel-drop devices using the slow light mode, and 3-port channel-drop devices using the resonant-tunneling process.

Journal ArticleDOI
TL;DR: A volume sampling method to generate three-dimensional patterns is proposed and a systematic SEM-based analysis of the microstructure gives new insights toward a better understanding of the femtosecond laser interaction with fused silica glass.
Abstract: We present novel results obtained in the fabrication of high-aspect ratio micro-fluidic microstructures chemically etched from fused silica substrates locally exposed to femtosecond laser radiation. A volume sampling method to generate three-dimensional patterns is proposed and a systematic SEM-based analysis of the microstructure is presented. The results obtained gives new insights toward a better understanding of the femtosecond laser interaction with fused silica glass (a-SiO2).

Journal ArticleDOI
TL;DR: Results of theoretical and experimental investigations of artifacts that can arise in spectral-domain optical coherence tomography (SD-OCT) and optical frequency domain imaging (OFDI) as a result of sample or probe beam motion are described.
Abstract: We describe results of theoretical and experimental investigations of artifacts that can arise in spectral-domain optical coherence tomography (SD-OCT) and optical frequency domain imaging (OFDI) as a result of sample or probe beam motion. While SD-OCT and OFDI are based on similar spectral interferometric principles, the specifics of motion effects are quite different because of distinct signal acquisition methods. These results provide an understanding of motion artifacts such as signal fading, spatial distortion and blurring, and emphasize the need for fast image acquisition in biomedical applications.

Journal ArticleDOI
TL;DR: An analytical expression for pulse propagation through a semi-infinite CROW in the case of weak coupling is obtained which fully accounts for the nonlinear dispersive characteristics.
Abstract: We use the coupling matrix formalism to investigate continuous-wave and pulse propagation through microring coupled-resonator optical waveguides (CROWs). The dispersion relation agrees with that derived using the tight-binding model in the limit of weak inter-resonator coupling. We obtain an analytical expression for pulse propagation through a semi-infinite CROW in the case of weak coupling which fully accounts for the nonlinear dispersive characteristics. We also show that intensity of a pulse in a CROW is enhanced by a factor inversely proportional to the inter-resonator coupling. In finite CROWs, anomalous dispersions allows for a pulse to propagate with a negative group velocity such that the output pulse appears to emerge before the input as in “superluminal” propagation. The matrix formalism is a powerful approach for microring CROWs since it can be applied to structures and geometries for which analyses with the commonly used tight-binding approach are not applicable.

Journal ArticleDOI
TL;DR: It is shown that the presence of the gain medium can compensate for the absorption losses in the metal and suggest that lossless gainassisted surface plasmon polariton propagation can be achieved in practice.
Abstract: The propagation of surface plasmon polaritons on metallic waveguides adjacent to a gain medium is considered. It is shown that the presence of the gain medium can compensate for the absorption losses in the metal. The conditions for existence of a surface plasmon polariton and its lossless propagation and wavefront behavior are derived analytically for a single infinite metal-gain boundary. In addition, the cases of thin slab and stripe geometries are also investigated using finite element simulations. The effect of a finite gain layer and its distance from the SPP waveguide is also investigated. The calculated gain requirements suggest that lossless gainassisted surface plasmon polariton propagation can be achieved in practice.

Journal ArticleDOI
TL;DR: An air-clad large-core single-transverse-mode ytterbium-doped photonic crystal fiber with a mode-field-diameter of 35 microm allowing for the frequency up-conversion of these pulses using narrow-bandwidth phase matched nonlinear crystals.
Abstract: We report on an air-clad large-core single-transverse-mode ytterbium-doped photonic crystal fiber with a mode-field-diameter of 35 µm, corresponding to a mode-field-area of ~1000 µm2. In a first experiment this fiber is used to amplify 10-ps pulses to a peak power of 60 kW without significant spectral broadening due to self-phase modulation allowing for the frequency up-conversion of these pulses using narrow-bandwidth phase-matched nonlinear crystals.

Journal ArticleDOI
TL;DR: It is demonstrated that arrays of optical vortices created with the holographic optical tweezer technique can assemble colloidal spheres into dynamically reconfigurable microoptomechanical pumps assembled by optical gradient forces and actuated by photon orbital angular momentum.
Abstract: Beams of light with helical wavefronts can be focused into ring-like optical traps known as optical vortices. The orbital angular momentum carried by photons in helical modes can be transferred to trapped mesoscopic objects and thereby coupled to a surrounding fluid. We demonstrate that arrays of optical vortices created with the holographic optical tweezer technique can assemble colloidal spheres into dynamically reconfigurable microoptomechanical pumps assembled by optical gradient forces and actuated by photon orbital angular momentum.

Journal ArticleDOI
TL;DR: A novel technique using an acousto-optic frequency shifter in optical frequency domain imaging (OFDI) eliminates the ambiguity between positive and negative differential delays, effectively doubling the interferometric ranging depth while avoiding image cross-talk.
Abstract: A novel technique using an acousto-optic frequency shifter in optical frequency domain imaging (OFDI) is presented. The frequency shift eliminates the ambiguity between positive and negative differential delays, effectively doubling the interferometric ranging depth while avoiding image cross-talk. A signal processing algorithm is demonstrated to accommodate nonlinearity in the tuning slope of the wavelength-swept OFDI laser source.

Journal ArticleDOI
TL;DR: In this article, a single-layer subwavelength periodic waveguide films with binary profiles are applied to design numerous passive guided-mode resonance elements and it is shown that the profile's Fourier harmonic content, along with the absolute value of the grating modulation strength, affects the resonance linewidth and their relative locations.
Abstract: Single-layer subwavelength periodic waveguide films with binary profiles are applied to design numerous passive guided-mode resonance elements. It is shown that the grating profile critically influences the spectral characteristics of such devices. In particular, the symmetry of the profile controls the resonance spectral density. Symmetric profiles generate a single resonance on either side of the second stopband whereas two resonances arise, one on each side of the band, for asymmetric structures. Moreover, the profile's Fourier harmonic content, along with the absolute value of the grating modulation strength, affects the resonance linewidths and their relative locations. Computed Brillouin diagrams are presented to illustrate many key properties of the resonant leaky-mode spectra in relation to modulation strength and profile symmetry at the second stopband. Associated mode plots elucidate the spatial distribution of the leaky-mode field amplitude at resonance and show that, for small modulation, the mode shape may be simple whereas at higher modulation, the shape appears as a complex mixture of modes. By computing device spectra as function of the modulation strength, the buildup of the final spectral properties is illustrated and the contributions of the various leaky modes clarified. The results presented include wavelength and angular spectra for several example devices including narrow linewidth bandpass filters with extended low sidebands for TE and TM polarization, wideband reflectors for TE and TM polarization, polarizer, polarization-independent element, and a wideband antireflector, all with only a single binary layer with one-dimensional periodicity. These results demonstrate new dimensions in optical device design and may provide complementary capability with the field of thin-film optics.

Journal ArticleDOI
TL;DR: The supercontinuum generation in a highly nonlinear photonic crystal fiber with two closely lying zero dispersion wavelengths is demonstrated, which has high spectral density and is extremely independent of the input pulse over a wide range of input pulse parameters.
Abstract: We demonstrate supercontinuum generation in a highly nonlinear photonic crystal fiber with two closely lying zero dispersion wavelengths. The special dispersion of the fiber has a profound influence on the supercontinuum which is generated through self-phase modulation and phasematched four-wave mixing and not soliton fission as in the initial photonic crystal fibers. The supercontinuum has high spectral density and is extremely independent of the input pulse over a wide range of input pulse parameters. Simulations show that the supercontinuum can be compressed to ultrashort pulses.

Journal ArticleDOI
TL;DR: Woodpile photonic crystal structures fabricated in organic-inorganic hybrid polymers (Ormocers) and investigation of their optical properties are reported.
Abstract: Two-photon polymerization (2PP) is a powerful technique for the fabrication of 3D micro- and submicro-structures. By applying laser powers that are only slightly above the polymerization threshold, 3D structuring of photosensitive materials with a resolution down to 100 nm can be realized. Here we report on woodpile photonic crystal structures fabricated in organic-inorganic hybrid polymers (Ormocers) and investigation of their optical properties. The fabricated crystals possess a photonic band gap in the near infrared spectral region. The polymeric woodpile structures can be used as templates for the fabrication of highly refractive TiO2 replicas. First results in this direction are presented.

Journal ArticleDOI
TL;DR: An all-optical modulator is demonstrated, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal.
Abstract: Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate an all-optical modulator, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. We demonstrate a modulation frequency of 2kHz for a moderate pump power of 2–3mW and describe two pump pulse regimes in which there is an order of magnitude difference between the decay times.

Journal ArticleDOI
TL;DR: Exceptional transmission through a photonic crystal waveguide Z-bend is obtained using this inverse design strategy and a large low loss bandwidth of more than 200 nm for the bandgap polarization is experimentally confirmed.
Abstract: Topology optimization is used to design a planar photonic crystal waveguide component resulting in significantly enhanced functionality. Exceptional transmission through a photonic crystal waveguide Z-bend is obtained using this inverse design strategy. The design has been realized in a silicon-on-insulator based photonic crystal waveguide. A large low loss bandwidth of more than 200 nm for the TE polarization is experimentally confirmed.