Showing papers in "Electronics Letters in 1992"
TL;DR: In this paper, the periodic amplification of solitons is shown to develop an instability, which is represented by the appearance of a series of discrete sidebands in the soliton power spectrum, which follow an inverse square root dependence on the amplification period.
Abstract: The periodic amplification of solitons is shown to develop an instability. This becomes evident through the appearance of a series of discrete sidebands in the soliton power spectrum. These sidebands do not exhibit the power tuning characteristic of the modulational instability, but instead follow an inverse square root dependence on the amplification period.<
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674 citations
TL;DR: In this paper, an unbalanced-interferometer wavelength discriminator was used for the detection of dynamic strain induced wavelength shifts in fiber Bragg grating sensors, which is capable of sub-nanostrain resolution (0.6 ne/√(Hz) at 500 Hz).
Abstract: A technique for the detection of dynamic strain induced wavelength shifts in fibre Bragg grating sensors is reported that is based on an unbalanced-interferometer wavelength discriminator, which is capable of subnanostrain resolution (0.6 ne/√(Hz) at 500 Hz) sensing.
510 citations
TL;DR: In this article, a novel method for the optical generation and distribution of millimetre waves is described, which is demonstrated at 36 GHz and an electrical linewidth limited by the resolution bandwidth of the spectrum analyser is achieved.
Abstract: A novel method for the optical generation and distribution of millimetre waves is described. The method is demonstrated at 36 GHz and an electrical linewidth limited by the resolution bandwidth of the spectrum analyser is achieved. No broadening of the electrical linewidth could be observed after propagation through 8 km of standard fibre.
492 citations
TL;DR: In this paper, nonlinear birefringence effects in a fiber ring laser cavity have been exploited to produce selfstarting, passive mode-locking to give 1.5 ps soliton pulses.
Abstract: Nonlinear birefringence effects in a fibre ring laser cavity have been exploited to produce selfstarting, passive mode-locking to give 1.5 ps soliton pulses.
451 citations
TL;DR: In this paper, nonlinear polarisation rotation has been used to additive pulse mode-lock (APM) a single loop erbium fiber ring laser, which is fully self-starting without triggering and has been made to produce single pulses of 452 fs duration per round trip time.
Abstract: Nonlinear polarisation rotation has been used to additive pulse mode-lock (APM) a single loop erbium fibre ring laser. The system is fully self-starting without triggering and has been made to produce single pulses of 452 fs duration per round trip time.
375 citations
TL;DR: In this article, a novel high speed CMOS integrated current comparator structure is presented which uses a source-follower input stage and a CMOS inverter as a positive feedback.
Abstract: A novel high speed CMOS integrated current comparator structure is presented which uses a source-follower input stage and a CMOS inverter as a positive feedback. It exhibits short propagation delay and occupies a small chip area.
330 citations
TL;DR: In this paper, the results on the thermo-optical induced modulation in a silicon etalon at 1.5 µm were reported. But the results were limited to the case where the etalon was used to measure the temperature of the silicon at this wavelength.
Abstract: Experimental results on thermo-optical induced modulation in a silicon etalon at 1.5/m are reported. The measurements have also allowed an accurate determination of the thermooptic effect in silicon at this wavelength.
274 citations
TL;DR: In this paper, the first observation of discrete jumps in the power output of an all-fibre passively mode-locked laser was reported and the discontinuities were associated with quantisation of the energy of the pulses circulating within the laser cavity.
Abstract: For the first time the observation of discrete jumps in the power output of an all-fibre passively mode-locked laser is reported. The discontinuities are associated with quantisation of the energy of the pulses circulating within the laser cavity.
243 citations
TL;DR: The first single-wavelength pumped, CW, room-temperature, blue upconversion laser was reported in this paper, which used Tm/sup 3+/ as the active ion in a fluorozirconate glass fibre.
Abstract: The authors report what they believe to be the first single-wavelength pumped, CW, room-temperature, blue upconversion laser. This 480 nm laser uses Tm/sup 3+/ as the active ion in a fluorozirconate glass fibre. Up to 60 mW of output power has been observed with a slope efficiency of 18% with respect to coupled pump power.<
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197 citations
TL;DR: The first experimental demonstration of a heterodyne optical phase-lock loop (OPLL) using semiconductor lasers without external cavities or other linewidth narrowing methods was reported in this article.
Abstract: The first experimental demonstration is reported of a heterodyne optical phase-lock loop (OPLL) using semiconductor lasers without external cavities or other linewidth narrowing methods. For a total loop propagation delay of 3 ns and a loop filter bandwidth of 700 MHz, a phase error variance of 1.02 rad2 was achieved in 500 MHz measurement bandwidth.
183 citations
TL;DR: Very short erbium-fibre laser with holographically written gratings in the core was reported in this article, achieving an output power of 181 mu W from a 2 cm long diode-pumped laser.
Abstract: Very short erbium-fibre lasers with holographically written gratings in the erbium-doped fibre core are reported. An output power of 181 mu W was obtained from a 2cm long diode-pumped laser. A 1 cm long diode pumped laser had an output power of 57 mu W. As would be expected for such short cavity lengths, these lasers are robustly singlemode.<
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TL;DR: The techniques of genetic algorithms are proposed as an alternative means of tuning digital PID controllers for complex multivariable plants with highly interactive dynamics.
Abstract: The techniques of genetic algorithms are proposed as an alternative means of tuning digital PID controllers. This use of genetic algorithms is particularly attractive because the same basic approach can always be readily used, even in the case of digital PID controllers for complex multivariable plants with highly interactive dynamics.
TL;DR: The continuous wave operation of an ZnSe/ZnMgSSe laser diode was achieved for the first time at 77K as mentioned in this paper, where the threshold current density was 225A/cm2.
Abstract: The continuous wave operation of an ZnSe/ZnMgSSe laser diode was achieved for the first time at 77K. Blue stimulated emission was observed at a wavelength of 447nm and the threshold current density was 225A/cm2.
TL;DR: In this paper, the power and RMS amplitude spectra of phase noise in optical fibres due to thermodynamic temperature fluctuations, including the effects of finite fibre outside diameter and retardation, were analyzed.
Abstract: Theoretical results are presented for the power and RMS amplitude spectra of phase noise in optical fibres due to thermodynamic temperature fluctuations, including the effects of finite fibre outside diameter and retardation. For a fibre optic Mach–Zehnder interferometer with 20m of 125μm diameter fibre in each arm, the (0–25) kHz phase noise is (5.1–1.3) × 10−7rad RMS/√(Hz) at 1300nm.
TL;DR: In this article, a whispering-gallery mode microdisc laser with singlemode operation and submilliamp threshold current at room temperature was demonstrated, and it was shown that the single-mode operation can achieve sub-milliamps threshold current.
Abstract: Electrically pumped whispering-gallery mode microdisc lasers with singlemode operation and submilliamp threshold current at room temperature are demonstrated.
TL;DR: A novel neural network that processes input vectors and attractors fully in complex space using complex weights is proposed and can be applied for ill-posed problems concerning realistic physical fields and continuous motion controls.
Abstract: A novel neural network that processes input vectors and attractors fully in complex space using complex weights is proposed. Real and imaginary data are treated consistently with an equivalent significance in nondegenerate complex space. This network can be applied for ill-posed problems concerning realistic physical fields and continuous motion controls. The dynamics are presented and demonstrated.
TL;DR: In this paper, a broadband (>50 nm) wavelength shifter capable of switching multigigabit data between optical frequencies in the 1.5 μm region is presented, based on gain saturation in a semiconductor optical amplifier.
Abstract: A broadband (>50 nm) wavelength shifter capable of switching multigigabit data between optical frequencies in the 1.5 μm region is presented. The device, based on gain saturation in a semiconductor optical amplifier, is tunable, has gain, and is nearly polarisation insensitive. Data degradation after wavelength shifting is negligible.
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TL;DR: In this paper, an erbium doped fluorozirconate fiber pumped at 0.97μm was used to achieve green power and slope efficiency against launched pump power of 15% at room temperature.
Abstract: 50mW of green power and slope efficiency against launched pump power of 15% have been obtained at room temperature in an erbium doped fluorozirconate fibre pumped at 0.97μm. Lasing tunability domain, pump wavelength tunability and the role of colasing at 1.55μm are described.
TL;DR: In this paper, a multiquantum-well distributed-feedback (DFB) laser array with a star coupler and optical amplifiers on the same chip is reported.
Abstract: The monolithic integration of a multiwavelength multiquantum-well distributed-feedback (DFB) laser array with a star coupler and optical amplifiers on the same chip is reported. As many as 18 individual wavelengths from a given output of the star coupler are launched into a lensed single-mode fibre.
TL;DR: In this paper, a microlenses have been fabricated directly on the ends of optical fibres which demonstrate 90% (-0.45 dB) coupling efficiencies to semiconductor lasers.
Abstract: Microlenses have been fabricated directly on the ends of optical fibres which demonstrate 90% (-0.45 dB) coupling efficiencies to semiconductor lasers. The lenses are made by laser micromachining a spinning fibre in a microlathe arrangement. Theoretically, it is possible to collect nearly 100% of the laser radiation with the aspheric lens design presented. >
TL;DR: In this article, a monolithic integrated 4×4 semiconductor laser amplifier gate switch arrays comprising 24 integrated laser amplifiers have been fabricated and evaluated and the net positive optical gain between fibres, high extinction ratio, and low crosstalk is reported.
Abstract: Monolithically integrated 4×4 semiconductor laser amplifier gate switch arrays comprising 24 integrated laser amplifiers have been fabricated and evaluated. Net positive optical gain between fibres, high extinction ratio, and low crosstalk are reported.
TL;DR: In this article, an optical data stream is used to mode-lock a fiber laser at (or an integer multiple of) the line rate, where a length of data transmission fibre is shared with the fiber laser and mode locking occurs through the process of cross-phase modulation.
Abstract: A novel all-optical clock recovery scheme in which an optical data stream is used to mode-lock a fibre laser at (or an integer multiple of) the line rate is experimentally demonstrated. A length of data transmission fibre is shared with the fibre laser and mode locking occurs through the process of crossphase modulation.
TL;DR: In this paper, the stability conditions for soliton generation in fiber lasers were determined and it was found that soliton interaction forces are reduced by bandwidth limited gain and fast saturable absorption.
Abstract: The stability conditions for soliton generation in fibre lasers are determined, and it is found that soliton interaction forces are reduced by bandwidth limited gain and fast saturable absorption.
TL;DR: In this article, the authors describe the design of a versatile analogue building block, termed an operational transresistance amplifer (OTRA), which has two low-input-impedance terminals and one low-output-IMpedance terminal.
Abstract: The Letter describes the design of a versatile analogue building block, termed an operational transresistance amplifer (OTRA). An operational transresistance amplifier has two low-input-impedance terminals and one low-output-impedance terminal. It is found to have a constant bandwidth indpendent of the gain in most closed-loop configurations. Simulation results are presented to demonstrate the constant-bandwidth performance. As an application example this amplifier is used to implement a MOSFET-C differentiator, of which analysis and simulation results are also presented.
TL;DR: In this paper, a stabilisation scheme for a mode-locked erbium fiber laser which relies on locking the pulse phase with that of the drive source is reported. And the first bit error rate (BER) measurement on such a laser has been demonstrated.
Abstract: A stabilisation scheme for a mode-locked erbium fibre laser which relies on locking the pulse phase with that of the drive source is reported. Using this scheme, the first bit-error-rate (BER) measurement on such a laser has been demonstrated. Stable error free operation at 2Gbit/s and a received power of 26dBm has been observed over a period of >0.5h showing the potential suitability of the laser as a transmission source.
TL;DR: In this article, a scanning force microscope probe for measuring ultrafast voltage signals is demonstrated, based on mixing due to the square-law force interaction present between the microscope tip and sample.
Abstract: A scanning force microscope probe for measuring ultrafast voltage signals is demonstrated. The new technique is based on mixing due to the square-law force interaction present between the microscope tip and sample. Correlation of 100 ps pulses and mixing up to 20 GHz have been achieved.
TL;DR: In this paper, the realisation of Er-doped glass planar waveguide amplifiers is reported, achieving a net gain of 13.7 dB for a silica-based waveguide at a wavelength of 1.535 μm with a 0dB gain pump threshold of 25 mW.
Abstract: The realisation of Er-doped glass planar waveguide amplifiers is reported. A net gain of 13.7 dB is achieved for a silica-based waveguide at a wavelength of 1.535 μm with a 0dB gain pump threshold of 25 mW.
TL;DR: By transmitting trains of 213 bit pseudorandom words in a recirculating loop, the authors demonstrated error-free (measured BER ≥ 10−10) soliton transmission at 5 Gbit/s, single channel, and at 10 Gbits/s in a two channel WDM, over paths as great as 15 400 km and 11 250 km, respectively.
Abstract: By transmitting trains of 213 bit pseudorandom words in a recirculating loop, we demonstrate ‘error-free’ (measured BER ≥10−10) soliton transmission at 5 Gbit/s, single channel, and at 10 Gbit/s in a two channel WDM, over paths as great as 15 400 km and 11 250 km, respectively.
TL;DR: In this article, a novel method of using two pump wavelengths to achieve high gains and enhanced noise performance in the 1.6 μm Er3+ doped fiber amplifier is demonstrated.
Abstract: A novel method of using two pump wavelengths to achieve high gains and enhanced noise performance in the 1.6 μm Er3+ doped fibre amplifier is demonstrated. By launching 82 mW of power at 1.48 μm and up to 1 mW at 1.555 μm, a maximum gain of 31 dB is achieved at 1.57 μm with gains in excess of 24 dB available between 1.57 and 1.605 μm. The noise figure is maintained below 5dB over this bandwidth, close to the theoretical minimum for a 1.48 μm pumped amplifier.
TL;DR: A 5 V half-wave voltage (V/sub pi /) electro-optic Ti:LiNbO/sub 3/ intensity modulator with a -7.5 dB (electrical) optical response at 40 GHz is demonstrated at 1.3 mu m as mentioned in this paper.
Abstract: A 5 V half-wave voltage (V/sub pi /) electro-optic Ti:LiNbO/sub 3/ intensity modulator with a -7.5 dB (electrical) optical response at 40 GHz is demonstrated at 1.3 mu m. A thick electrode structure is used in conjunction with a thin substrate to achieve a near optical-microwave phase match and a broadband electrical response. >