Showing papers in "Electronics Letters in 1986"
TL;DR: In this paper, a model for polarisation dispersion in single-mode fibres of arbitrary length and configuration is proposed based on the existence of principal states of polarisation, i.e., two orthogonal input states of polarity whose corresponding output states exhibit zero dispersion.
Abstract: We describe a model for polarisation dispersion in single-mode fibres of arbitrary length and configuration that is based on the existence of principal states of polarisation. These are two orthogonal input states of polarisation whose corresponding output states exhibit zero dispersion in their state of polarisation to first order.
584 citations
TL;DR: In this paper, it is shown that by using a strained-layer superlattice to form the active region of a quantum-well laser, the threshold current can be reduced and Auger recombination and inter-valence band absorption can be effectively eliminated.
Abstract: It is shown that by using a strained-layer superlattice to form the active region of a quantum-well laser the threshold current can be reduced and Auger recombination and inter-valence band absorption can be effectively eliminated. The band-structure requirements are discussed generally and might be achieved by alternative methods.
527 citations
TL;DR: In this article, a single-mode Q-switched Q-mode fiber laser source is described, which is tunable over 25 nm in the wavelength region of 1.55 μm and produces in excess of 2 W peak power in a Qswitched mode.
Abstract: A new single-mode fibre laser source is described. The laser is tunable over 25 nm in the wavelength region of 1.55 μm and produces in excess of 2 W peak power in a Q-switched mode.
214 citations
TL;DR: In this article, the reduction of excess loss in practical single-mode fiber tapers requires the local taper angle to be smaller than an intuitive value, and the qualitative criterion is quantified for various taper shapes.
Abstract: The reduction of excess loss in practical single-mode fibre tapers requires the local taper angle to be smaller than an intuitive value. This qualitative criterion is quantified for various taper shapes. For a given taper length, loss is minimal for shapes which are similar to the shape obtained by assuming the intuitive value of angle everywhere along the taper.
193 citations
TL;DR: In this article, a multiquantum barrier (MQB) was proposed and the reflectivity of an electron from the MQB is given theoretically and it is shown that the effective potential barrier of MQB can be higher than that of a classical bulk barrier.
Abstract: In the letter we propose a new multi-quantum structure, namely a multiquantum barrier (MQB). The reflectivity of an electron from the MQB is given theoretically and it is shown that the effective potential barrier of MQB can be higher than that of a classical bulk barrier.
166 citations
TL;DR: In this paper, the transistors determining the transconductance do not carry bias current, operate with large gate-source voltage, and are signal-driven in such a way that their nonlinearities are eliminated.
Abstract: MOS transconductors are discussed in which the transistors determining the transconductance do not carry bias current, operate with large gate-source voltage, and are signal-driven in such a way that their nonlinearities are eliminated. An integrator implemented using one of the proposed circuits exhibited measured total harmonic distortion of less than 0.1% for differential input signals of 2.5 V p-p, and less than 1% for 5 V p-p.
158 citations
TL;DR: In this paper, spontaneous backward Brillouin scattering is demonstrated to be a sensitive probe of fibre characteristics using a heterodyne detection technique and relative differences in GeO2 concentration from fibre to fibre as small as 0.01% can be detected.
Abstract: Spontaneous backward Brillouin scattering is demonstrated to be a sensitive probe of fibre characteristics using a heterodyne detection technique. Relative differences in GeO2 concentration from fibre to fibre as small as 0.01% can be detected.
154 citations
TL;DR: In this paper, the induced amplitude modulation of sinusoidally phase-modulated CW 1.5?m laser light propagating in a single-mode fiber was measured.
Abstract: We have measured the induced amplitude modulation of sinusoidally phase-modulated CW 1.5 ?m laser light propagating in a single-mode fibre. Amplitude modulation approaching 100% was observed for light phase-modulated at 4 GHz and transmitted through 50 km of fibre. PM-AM conversion produces a power penalty in coherent transmission systems.
120 citations
TL;DR: In this article, a universal second-order active filter network employing CCII-type current conveyors is reported, which offers wide bandwidth, high input impedance and independent control of?0, Q and voltage gain with separate grounded resistors.
Abstract: A universal second-order active filter network employing CCII-type current conveyors is reported. The circuit offers wide bandwidth, high input impedance and independent control of ?0, Q and voltage gain with separate grounded resistors. The circuit also uses grounded capacitors and is therefore ideal for integration.
109 citations
TL;DR: In this article, a strictly nonlocking 8×8 integrated optics switch matrix in Ti: LiNbO3 was presented, which consisted of 64 directional couplers on one chip.
Abstract: We report on a strictly nonlocking 8×8 integrated optics switch matrix in Ti: LiNbO3. The matrix comprises 64 directional couplers on one chip. Insertion losses less than 7 dB have been measured. The extinction ratio has an average value of 30.5 dB for the directional couplers.
107 citations
IBM1
TL;DR: AlGaAs ridge single-quantum-well graded-index separate confinement heterostructure (SQW GRIN-SCH) with typical threshold currents of 9 mA and differential quantum efficiencies between 80% and 85% for 0.4 mm-long cavities have been fabricated with molecular beam epitaxy.
Abstract: AlGaAs ridge single-quantum-well graded-index separate confinement heterostructure (SQW GRIN-SCH) lasers with typical threshold currents of 9 mA and differential quantum efficiencies between 80% and 85% for 0.4 mm-long cavities have been fabricated with molecular beam epitaxy. Continuous-wave light output increases linearly with the drive current up to approximately 15 times the threshold current. The lasers fail catastrophically at power levels between 65 mW/facet and 85 mW/facet, corresponding to power densities between 2.6 MW/cm2 and 3.4 MW/cm2.
CNET1
TL;DR: In this paper, a 1.26 μm optical amplifier with a facet modal reflectivity below 0.0001 has been used in a 58 mm-long grating external cavity.
Abstract: A 1.26 μm optical amplifier with a facet modal reflectivity below 0.0001 has been used in a 58 mm-long grating external cavity. The lasing wavelength has been continuously tuned without mode hopping over a range of 15 nm by combined translation-rotation of the diffraction grating. A linewidth of 20 kHz has been derived from heterodyne beat frequency measurements between two tunable external-cavity lasers.
TL;DR: In this paper, temperature distribution with an Nd3+-doped multimode optical fiber was measured to an accuracy of 2°C over the range -50°C to +100°C.
Abstract: We report the measurement of temperature distribution with an Nd3+-doped multimode optical fibre. By exploiting the temperature-sensitive absorption bands of the doped-glass core, temperature was measured to an accuracy of 2°C over the range -50°C to +100°C. A spatial resolution of 15m over a fibre length of 140m was obtained.
TL;DR: In this paper, a new switched-capacitor integrator with low sensitivity to finite amplifier gain is described, requiring very little extra chip area as compared to the uncompensated integrator.
Abstract: A new switched-capacitor integrator with low sensitivity to finite amplifier gain is described. The circuit is simple, requiring very little extra chip area as compared to the uncompensated integrator. It is compared with previously proposed finite gain compensated switched-capacitor integrators.
TL;DR: In this article, a low-loss high-silica single-mode channel optical waveguides of 0.1 dB/cm have been fabricated on crystal silicon substrates with fibre coupling losses of less than 0.05 dB by flame hydrolysis deposition and reactive ion etching.
Abstract: Low-loss high-silica single-mode channel optical waveguides of 0.1 dB/cm have been fabricated on crystal silicon substrates with fibre coupling losses of less than 0.05 dB by flame hydrolysis deposition and reactive ion etching. Directional couplers have also been fabricated with excess loss of 0.5 dB by this waveguide fabrication technique.
TL;DR: In this article, the second harmonic generation has been observed from Langmuir-Blodgett multilayer arrays containing two active components, and preliminary results indicate a significant enhancement of the second-order polarisability for this type of supermolecular array.
Abstract: Second harmonic generation has been observed from Langmuir-Blodgett multilayer arrays containing two active components. Both materials were based on long chain donor-acceptor dye compounds, but were designed with the donor-acceptor groups in opposite senses with respect to the hydrocarbon chain. Preliminary results indicate a significant enhancement of the second-order polarisability for this type of supermolecular array.
TL;DR: In this paper, a 1.5?m range multi-electrode distributed feedback laser was tuned electrically, maintaining a stable single-mode oscillation without mode jumping.
Abstract: Broad wavelength tuning under single-mode oscillation is achieved for a 1.5 ?m range multi-electrode distributed feedback laser. The lasing wavelength can be tuned electrically, maintaining a stable single-mode oscillation without mode jumping. The tuning has reached over 20 ? under a noticeable condition of constant power (5mW), with a sufficient side-mode suppression ratio over 30 dB.
TL;DR: In this article, a novel homodyne detection technique which avoids optoelectronic phase locking by using stimulated Brillouin gain to selectively amplify the signal carrier is described, which avoids optical phase locking.
Abstract: A novel homodyne detection technique which avoids optoelectronic phase-locking by using stimulated Brillouin gain to selectively amplify the signal carrier is described.
TL;DR: In this article, the fabrication and characterisation of efficient, narrowband fiber-optic filters using surface-relief gratings etched into monomode fiber are described, with a device with 92% reflectivity and 1·8 nm bandwidth at 1·3 μm wavelength using a first-order Bragg grating with a high-index overlayer.
Abstract: The fabrication and characterisation of efficient, narrowband fibre-optic filters utilising surface-relief gratings etched into monomode fibre are described. A device with 92% reflectivity and 1·8 nm bandwidth at 1·3 μm wavelength using a first-order Bragg grating with a high-index overlayer is reported.
TL;DR: In this article, an InGaAsP waveguide PIN photodetector was proposed for light absorption perpendicular to current collection, a feature that results in high-speed, high-efficiency and relatively bias-insensitive operation.
Abstract: We describe an InGaAsP waveguide PIN photodetector that (unlike conventional PINs) provides for light absorption perpendicular to current collection, a feature that results in high-speed, high-efficiency and relatively bias-insensitive operation. Our uncoated, packaged device has displayed impulse response of 40 ps (Tektronix S-4 sampling head) and efficiency of 25% at zero bias.
TL;DR: In this paper, the authors evaluated the relationship between the cooling capability and the channel width with a constant pressure drop for micro-grooved cooling fins, and found that there are optimal channel widths which give rise to the maximum allowable power density.
Abstract: We have evaluated the relationship between the cooling capability and the channel width with a constant pressure drop for microgrooved cooling fins, and found that there are optimal channel widths which give rise to the maximum allowable power density. There are also optimal microgrooved cooling fin structures in which enlarged channel widths are sufficient to cool high-power-consumption wafer-scale integrated chips with a pressure drop of only 200 kg/m2.
TL;DR: In this paper, a beam expander is constructed from a singlemode optical fiber which has been overjacketed in a capillary of lower refractive index and then tapered.
Abstract: A simple practical and controllable beam expander can be constructed from a single-mode optical fibre which has been overjacketed in a capillary of lower refractive index and then tapered. The properties of such an expanded beam in a gap device are also investigated.
TL;DR: In this article, the design and implementation of a continuous-time lowpass filter with voltage-controlled cutoff frequency and passband ripple is presented. The circuit uses a linearised CMOS transconductor as a basic integrating building block and employs a voltage controlled phase adjustment scheme in the integrator to compensate for excess phase in the transconductance at high frequencies.
Abstract: The design and implementation of a continuous-time lowpass filter with voltage-controlled cutoff frequency and passband ripple is presented The circuit uses a linearised CMOS transconductor as a basic integrating building block A voltage-controlled phase-adjusting scheme is employed in the integrator to compensate for excess phase in the transconductance at high frequencies The fabricated filter is capable of realising cutoff frequencies as high as 2 MHz and handles single-ended input signals up to 4 V p-p with less than 1% distortion
TL;DR: A relationship between the discrete cosine transform (DCT) and the discrete Hartleytransform (DHT) is derived and it leads to a new fast and numerically stable algorithm for the DCT.
Abstract: A relationship between the discrete cosine transform (DCT) and the discrete Hartley transform (DHT) is derived. It leads to a new fast and numerically stable algorithm for the DCT.
TL;DR: The presence of a floating substrate in SOI transistors gives rise to a decrease of threshold voltage when drain voltage is increased as discussed by the authors, which brings about a dramatic decrease of the so-called "kink effect".
Abstract: The presence of a floating substrate in SOI transistors gives rise to a decrease of threshold voltage when drain voltage is increased. When the devices are made in a very thin silicon film, the latter is completely depleted when the device is in the 'on' state, and no part of the film can act as a floating substrate. This brings about a dramatic decrease of the so-called 'kink effect'.
TL;DR: In this paper, a balanced dual-detector receiver which requires low localoscillator power has been designed and fabricated for optical heterodyne detection at 1·5?m wavelength and Gbit/s rates.
Abstract: A balanced dual-detector receiver which requires low local-oscillator power has been designed and fabricated for optical heterodyne detection at 1·5 ?m wavelength and Gbit/s rates. The receiver consists of two InGaAs PIN photodiodes connected with opposite polarities to a high-impedance GaAs FET amplifier. Frequency response, noise suppression and noise spectrum measurements are reported.
TL;DR: In this paper, 30 ps pulses from a diode laser have been used to perform noncontact electric field measurements using a versatile ''finger probe? electro-optic sampling technique''.
Abstract: 30 ps pulses from a diode laser have been used to perform noncontact electric field measurements using a versatile `finger probe? electro-optic sampling technique.
TL;DR: In this article, a model for floating gate faults in MOS integrated circuits is introduced, and it is experimentally demonstrated that these models are mask-topology-dependent and the logic state of the gate can be stuck-at, undefined or influenced.
Abstract: Models for floating gate faults in MOS integrated circuits are introduced. It is experimentally demonstrated that these models are mask-topology-dependent. The logic state of the gate can be stuck-at, undefined or influenced. In the case of an influenced gate a ‘pseudo-MOS transistor’ is defined.
TL;DR: In this article, a simple architecture for bidirectional optical fiber transmission using an MQW device as both modulator and photodetector was proposed, which achieved transmission of 50 Mbit/s and 600 M bit/s in both directions over one 3.34 km-long single-mode fiber at 860 nm wavelength.
Abstract: We demonstrate a simple architecture for bidirectional optical fibre transmission which uses an MQW device as both modulator and photodetector. We achieved transmission of 50 Mbit/s and 600 Mbit/s in both directions over one 3.34 km-long single-mode fibre at 860 nm wavelength. Coherent Rayleigh interference was found to be a limiting factor in single-source bidirectional systems.
TL;DR: In this article, the first successful monolithic integration of InGaAsP/InP distributed feedback (DFB) lasers and MQW optical modulators using LPE (liquid phase epitaxy)/MBE (modlecular beam epitaxy) hybrid growth was reported.
Abstract: The first successful monolithic integration of InGaAsP/InP distributed feedback (DFB) lasers and InGaAs/InAlAs multiple quantum well (MQW) optical modulators using LPE (liquid phase epitaxy)/MBE (modlecular beam epitaxy) hybrid growth reported. A 14% light output modulation is observed in this integrated device.