Showing papers in "IEEE Photonics Technology Letters in 2000"
TL;DR: In this paper, the authors describe the measured group-velocity dispersion characteristics of several air-silica photonic crystal fibers with anomalous group velocity dispersion at visible and near-infrared wavelengths.
Abstract: We describe the measured group-velocity dispersion characteristics of several air-silica photonic crystal fibers with anomalous group-velocity dispersion at visible and near-infrared wavelengths. The values measured over a broad spectral range are compared to those predicted for an isolated strand of silica surrounded by air. We demonstrate a strictly single-mode fiber which has zero dispersion at a wavelength of 700 mm. These fibers are significant for the generation of solitons and supercontinua using ultrashort pulse sources.
683 citations
TL;DR: In this article, a novel wavelength division multiplexing (WDM) source employing an uncooled and unisolated Fabry-Perot semiconductor laser diode (F-P SLD) was proposed.
Abstract: We propose and demonstrate a novel wavelength-division-multiplexing (WDM) source employing an uncooled and unisolated Fabry-Perot semiconductor laser diode (F-P SLD). The output wavelength of F-P SLD is locked to the externally injected narrow-band amplified spontaneous emission (ASE). The measured side-mode suppression ratio of the wavelength-locked F-P SLD is larger than 29 dB, when the extinction ratio of the directly modulated light output is above 13 dB. We achieved error-free transmission of 155-Mb/s data over 120 km of nondispersion-shifted fiber. We also propose a cost-effective WDM passive optical network architecture based on the proposed light sources.
391 citations
TL;DR: In this article, the second-and third-order filter response was experimentally shown in filters constructed using mutually coupled microring resonators, and the effect of varying interesonator coupling on filter passband shape was studied.
Abstract: Second- and third-order filter response is experimentally shown in filters constructed using mutually coupled microring resonators. The higher order filters have passbands with sharper rolloff and flatter tops, and greater out-of-band rejection than previously demonstrated microring filters, which were first order. The effect of varying interesonator coupling on filter passband shape was studied.
382 citations
TL;DR: In this paper, a fiber-optic sensor based on a superstructure fiber Bragg grating (SFBG) for simultaneous strain and temperature measurement is proposed and demonstrated, where the transmission spectrum of the sensor possesses several narrow-band loss peaks situated on the slope of a broadband loss peak.
Abstract: A novel and simple fiber-optic sensor based on a superstructure fiber Bragg grating (SFBG) for simultaneous strain and temperature measurement is proposed and demonstrated. The transmission spectrum of the sensor possesses several narrow-band loss peaks situated on the slope of a broad-band loss peak. By measuring the transmitted intensity and wavelength at one of the loss peaks, strain and temperature can be determined simultaneously. The accuracy of the sensor in measuring strain and temperature is estimated to be /spl plusmn/20 /spl mu//spl epsiv/ in a range from 0 to 1200 /spl mu//spl epsiv/ and /spl plusmn/1.2/spl deg/C from 20/spl deg/C to 120/spl deg/C, respectively.
301 citations
TL;DR: In this paper, a very low continuous-wave threshold current of 1.2 mA with a threshold current density of 28 A/cm/sup 2/ was achieved with p-up mounting at room temperature.
Abstract: Data are presented on low threshold, 1.3-/spl mu/m oxide-confined InGaAs-GaAs quantum dot lasers. A very low continuous-wave threshold current of 1.2 mA with a threshold current density of 28 A/cm/sup 2/ is achieved with p-up mounting at room temperature. For slightly larger devices the continuous-wave threshold current density is as low as 19 A/cm/sup 2/.
295 citations
TL;DR: In this paper, the analytic theory governing the complete scattering response of two-dimensional (2D) microring resonator arrays is developed, the method is applicable to arbitrary interconnections of general four-port, single polarization nodes.
Abstract: The analytic theory governing the complete scattering response of two-dimensional (2-D) microring resonator arrays is developed, The method is applicable to arbitrary interconnections of general four-port, single polarization nodes. An 8/spl times/8 cross-grid array of vertically coupled glass microring resonators is fabricated for test purposes.
259 citations
TL;DR: In this paper, the authors analyzed intrachannel nonlinear effects in high-bit-rate transmission systems based on short optical pulses that are dispersion compensated and showed that the magnitude of nonlinear impairments reduces monotonically with the reduction of pulse width and with the increase of the dispersion coefficient.
Abstract: We analyze intrachannel nonlinear effects in high-bit-rate transmission systems based on short optical pulses that are dispersion compensated. We perform an analytical study of a generic example with two pulses, in which case the nonlinearity shifts the pulses in time and results in the generation of leading and trailing pulse echoes. We show that in all the relevant range of parameters, the magnitude of the nonlinear impairments reduces monotonically with the reduction of pulse width and with the increase of the dispersion coefficient.
259 citations
TL;DR: In this paper, a surface-emitting semiconductor laser has been passively mode-locked in an external cavity incorporating a semiconductor saturable absorber mirror, with a repetition rate variable around 4.4 GHz.
Abstract: A surface-emitting semiconductor laser has been passively mode locked in an external cavity incorporating a semiconductor saturable absorber mirror. The gain medium consists of a stack of 12 InGaAs-GaAs strained quantum wells, grown above a Bragg mirror structure, and pumped optically by a high-brightness diode laser. The mode-locked laser emits pulses of 22-ps full-width at half maximum duration at 1030 nm, with a repetition rate variable around 4.4 GHz.
223 citations
NEC1
TL;DR: In this article, the authors examined the dynamic properties of high-aspect-ratio InAs-quantum-dot (QD) laser at room temperature and found that low chirp in the lasing wavelength under 1-GHz current modulation was found in the quantum dot lasers.
Abstract: We have examined the dynamic properties of high-aspect-ratio InAs-quantum-dot (QD) lasers at room temperature. A novel characteristic of low chirp in the lasing wavelength under 1-GHz current modulation was found in the quantum dot lasers. This is more than one order of magnitude less than the typical chirp (0.2-nm) found in a conventional quantum well laser that we used as a reference. Low chirp was obtained not only in the ground state lasing but in the second level lasing of quantum dots as well.
190 citations
TL;DR: In this article, an effective method of realizing optical bend sensing based on the measurement of bending-curvature encoded resonance mode splitting of long-period fiber grating was proposed.
Abstract: We report an effective new method of realizing optical bend sensing based on the measurement of bending-curvature encoded resonance mode splitting of long-period fiber grating. The bending induced mode splitting exhibits a near-linear response and the bending sensitivity achieved by this method is nearly four times higher than the previously reported wavelength shift detection method. The evolution of the transmission loss under bending appears dependent on the initial mode coupling strength.
181 citations
TL;DR: In this paper, the ultrafast dynamics of gain and refractive index in an electrically pumped InAs-InGaAs quantum-dot (QD) optical amplifier are measured at room temperature using differential transmission with femtosecond time resolution.
Abstract: The ultrafast dynamics of gain and refractive index in an electrically pumped InAs-InGaAs quantum-dot (QD) optical amplifier are measured at room temperature using differential transmission with femtosecond time resolution. Both absorption and gain regions are investigated. While the absorption bleaching recovery occurs on a picosecond time scale, the gain compression recovers with /spl sim/100-fs time constant, making devices based on such dots promising for high-speed optical communications.
TL;DR: The wavelength of InAs quantum dots in an In/sub 0.15/Ga/sub sub 0.85/As quantum-well (DWELL) laser grown on a GaAs substrate has been extended to 1.3-/spl mu/m as discussed by the authors.
Abstract: The wavelength of InAs quantum dots in an In/sub 0.15/Ga/sub 0.85/As quantum-well (DWELL) lasers grown on a GaAs substrate has been extended to 1.3-/spl mu/m. The quantum dot lasing wavelength is sensitive to growth conditions and sample thermal history resulting in blue shifts as much as 73 nm. The room temperature threshold current density is 42.6 A cm/sup -2/ for 7.8-mm cavity length cleaved facet lasers under pulsed operation.
TL;DR: In this article, a return-to-zero data wavelength conversion was demonstrated using cross-phase modulation in an optical fiber with subsequent conversion of phase modulation to amplitude modulation using an optical filter.
Abstract: 40-Gb/s return-to-zero data wavelength conversion is demonstrated using cross-phase modulation in an optical fiber with subsequent conversion of phase modulation to amplitude modulation using an optical filter. The scheme is potentially ultrahigh speed and can be made polarization independent.
TL;DR: In this paper, two experimental realizations of zero-type (notch) filters using GaAs-AlGaAs microring resonators were reported, the first is a ring coupled to one side of a Mach-Zehnder interferometer, the Y-branch of which has an effective splitting angle of 50/spl deg/ with 0.5dB loss.
Abstract: Microresonator filters reported so far have been all-pole-type filters. We report two experimental realizations of zero-type (notch) filters using GaAs-AlGaAs microring resonators. The first is a ring coupled to one side of a Mach-Zehnder interferometer, the Y-branch of which has an effective splitting angle of 50/spl deg/ with 0.5-dB loss. The second is a ring whose loss exactly matches the coupling to the input/output waveguide with an extinction greater than 20 dB.
TL;DR: In this article, an all-active SOA-based Mach-Zehnder device, employed as a wavelength converter, is shown capable of improving the OSNR by more than 20 dB at this bit rate, thereby resulting in penalty reduction.
Abstract: All-optical 2R and 3R regeneration techniques are investigated at 40 Gb/s. It is shown that an all-active SOA-based Mach-Zehnder device, employed as a wavelength converter, is capable of improving the OSNR by more than 20 dB at this bit rate, thereby resulting in penalty reduction. Furthermore, simultaneous all-optical wavelength conversion and demultiplexing from 40 to 10 Gb/s is demonstrated showing that the scheme, which also has a 3R regeneration capability, is feasible in a combined OTDM/WDM network.
TL;DR: In this paper, the effects of imperfect third-order dispersion compensation in high-bit-rate WDM transmission systems employing standard single-mode fiber are investigated. And analytical expressions giving optimum values of dispersion precompensation minimizing the distortion due to the intrachannel nonlinear effects are derived.
Abstract: Intrachannel cross-phase modulation and four-wave mixing in high-bit-rate WDM transmission systems employing standard single-mode fiber are investigated. The effects of imperfect third-order dispersion compensation are included in the study and analytical expressions giving optimum values of dispersion precompensation minimizing the distortion due to the intrachannel nonlinear effects are derived.
TL;DR: In this paper, the authors show that two defect-free optical isolators with two defects possess sufficient freedom to attain high transmission over a large range of rotation angles in very short lengths.
Abstract: Photonic crystals containing defects produce enhanced Faraday rotation but existing designs have low intensity output. We show that designs with two-defects possess sufficient freedom to attain high transmission over a large range of rotation angles in very short lengths. We optimize such systems for 45/spl deg/ rotation in optical isolators.
TL;DR: In this paper, light is coupled from the guided mode along one tapered optical fiber into the whispering gallery modes around the circumference of another by tracking, at different points along it, the wavelengths at which these modes exist.
Abstract: Light is coupled from the guided mode along one tapered optical fiber into the whispering gallery modes around the circumference of another. Small diameter variations in the second fiber are measured by tracking, at different points along it, the wavelengths at which these modes exist. The measurement does not require any optical alignment, and its resolution can be 1 part in 10 000 or better.
TL;DR: In this article, a very low insertion loss silica-based arrayed-waveguide grating (AWG) achieved using a novel structure, which has vertically tapered waveguides between arrays to reduce the slab-to-arrayed waveguide transition loss.
Abstract: We propose and demonstrate a very low insertion loss silica-based arrayed-waveguide grating (AWG) achieved using a novel structure, which has vertically tapered waveguides between arrayed-waveguides to reduce the slab-to-arrayed-waveguide transition loss. A spot-size converter is also incorporated in the AWG to reduce the fiber-to-waveguide coupling loss. The structure can be formed by a process involving the conventional photolithography and reactive ion etching. The structure provided a loss reduction of 1.5 dB. Moreover, we have successfully obtained a minimum insertion loss of 0.75 dB with a crosstalk of -40 dB and polarization-independent operation.
TL;DR: In this article, a 20 Gb/s pseudodata pattern using a semiconductor optical amplifier-based ultrafast nonlinear interferometer (UNI) switch with low pattern dependence and low switching energies is achieved.
Abstract: All-optical Boolean XOR is demonstrated on a 20 Gb/s pseudodata pattern using a semiconductor optical amplifier-based ultrafast nonlinear interferometer (UNI) switch. Bit pattern switching with low-pattern dependence and low switching energies is achieved.
TL;DR: In this paper, a sampled-grating distributed Bragg reflector laser with an integrated semiconductor-optical-amplifier was used to achieve a quasicontinuous tuning range of over 50 nm and peak output powers greater than +8 dBm.
Abstract: High output powers and wide range quasicontinuous tuning have been achieved in a sampled-grating distributed Bragg reflector laser with an integrated semiconductor-optical-amplifier. Using an amplifier with a curved passive output waveguide to suppress back reflection, we have achieved a quasicontinuous tuning range of over 50 nm and peak output powers greater than +8 dBm. Optimizing the device structure and the sampled-grating mirror design has enabled tuning ranges of up to 72 nm in devices without amplifiers.
NEC1
TL;DR: In this article, an eight-channel wavelength-selectable microarray distributed feedback laser diodes (DFB-LD's) with a monolithically integrated 8/spl times/1 multimode-interference (MMI) optical combiner, a semiconductor optical amplifier (SOA), and an electroabsorption (EA) modulator were developed.
Abstract: We developed compact (1.136 mm/sup 2/) eight-channel wavelength-selectable microarray distributed feedback laser diodes (DFB-LD's) with a monolithically integrated 8/spl times/1 multimode-interference (MMI) optical combiner, a semiconductor optical amplifier (SOA), and an electro-absorption (EA) modulator. By using /spl plusmn/10/spl deg/C thermal tuning, an addressable wavelength range of 15.3 nm with uniform device characteristics and 2.5-Gb/s modulation performance were successfully demonstrated.
TL;DR: In this paper, an impactionization-engineered structure for the multiplication region of avalanche photodiodes is presented, which achieves high gain, low dark current, and very low noise.
Abstract: We demonstrate an impact-ionization-engineered structure for the multiplication region of avalanche photodiodes. By enhancing the control of the impact-ionization position, the structure achieved high gain, low dark current, and very low noise.
TL;DR: In this paper, a new scheme for all-optical signal reshaping is proposed and demonstrated, where strongly depleted mixing between a CW pump and a noisy non-return-to-zero (NRZ) signal in a common fiber can provide wavelength-converted signals exhibiting excellent intensity-noise cancellation.
Abstract: A new scheme for all-optical signal reshaping is proposed and demonstrated. The strongly depleted mixing between a CW pump and a noisy nonreturn-to-zero (NRZ) signal in a common fiber can provide wavelength-converted signals exhibiting excellent intensity-noise cancellation. Numerical simulations confirm almost complete suppression of intensity fluctuations, simultaneously occurring at several different wavelengths.
TL;DR: In this paper, a single-section, compact, passive polarization converter has been designed and fabricated on GaAs-AlGaAs, using an optimized waveguide structure with angled-facets to obtain 90/spl deg/-polarization rotation in a single section.
Abstract: A single-section, compact, passive polarization converter has been designed and fabricated on GaAs-AlGaAs. The device uses an optimized waveguide structure with angled-facets to obtain 90/spl deg/-polarization rotation in a single section; this waveguide structure eliminates the need for longitudinal variation and hence avoids any section-to-section coupling losses. A transverse electric (TE) to transverse magnetic (TM) polarization conversion of 96% is achieved for a conversion length of /spl ap/720 /spl mu/m.
NEC1
TL;DR: In this article, a hybrid-integrated symmetric Mach-Zehnder all-optical switch was developed for demultiplexing of 168-Gb/s data pulses at a repetition rate of 10 GHz with this switch.
Abstract: We have developed a hybrid-integrated symmetric Mach-Zehnder all-optical switch and evaluated the demultiplexing of 168-Gb/s data pulses at a repetition rate of 10 GHz with this switch. A compact, stable device was realized by assembling semiconductor optical amplifiers as nonlinear waveguides on a planar lightwave circuit in a self-aligned manner. A 6.0-ps switching window needed for 168-Gb/s demultiplexing was provided by the push-pull operation of the symmetric Mach-Zehnder all-optical switch. Demultiplexed signal light showed a high extinction ratio of better than 18 dB. Error-free demultiplexing with a bit error rate of 10/sup -11/ was achieved.
TL;DR: In this article, a magnetostrictive sensor head with temperature compensation has been developed for measurement of static magnetic fields, which consists on two different alloys with similar thermal expansion coefficient one of which has a giant magnetostriction, the expansion of both materials produced by heat and magnetism is detected by two fiber gratings.
Abstract: A magnetostrictive sensor head with temperature compensation has been developed for measurement of static magnetic fields. The device consists on two different alloys with similar thermal expansion coefficient one of which has a giant magnetostriction, the expansion of both materials produced by heat and magnetism is detected by two fiber gratings. One of the gratings measures the temperature of the sensor and the difference between the wavelengths reflected by the gratings is a measurement of the magnetically induced strain.
TL;DR: In this article, a fiber grating tap was used as a feedback element to control the in-fiber polarimeter and demonstrated the stable, broadband (>70 nm) operation of the fiber polarimeter.
Abstract: We fabricate highly blazed, polarization-sensitive fiber grating taps and show how these may be used in combination with a UV-induced fiber waveplate to form a compact, in-fiber polarimeter. We show how the polarimeter may be employed as a feedback element to control polarization and use the feedback loop to demonstrate the stable, broadband (>70 nm) operation of the fiber polarimeter.
TL;DR: In this paper, the first experimental demonstration of millimeter-wave modulated optical signal generation by an optical injection phase-lock loop was reported, where a 36 GHz signal was generated by combining optical sideband injection locking with optical phase-locked loop techniques for two fiber-coupled DFB lasers.
Abstract: We report the first experimental demonstration of millimeter-wave modulated optical signal generation by an optical injection phase-lock loop. A 36-GHz signal was generated by combining optical sideband injection locking with optical phase-lock loop techniques for two fiber-coupled DFB lasers. Single sideband noise spectral density of -92 dBc/Hz at 10 kHz offset, and phase-error variance lower than 0.005 rad/sup 2/ in a 100 MHz bandwidth were measured. The locking bandwidth exceeded 30 GHz.
TL;DR: In this article, the authors derived efficient modeling equations for the average power analysis of Raman amplifiers (RAs) from the standard propagation equations, and applied these equations to the numerical analysis of practical RA-based systems.
Abstract: For the first time, we derive efficient modeling equations for the average power analysis of Raman amplifiers (RAs) from the standard propagation equations. Applications of these equations to the numerical analysis of practical RA-based systems show a reduction in computation time of over two orders of magnitude compared with the direct integration approach based on ordinary coupled differential equations, while reproducing all the essential system performances precisely. In addition to enhanced computational efficiency, the derived equations also give deeper insights into the detailed dynamics of RAs.