Showing papers on "Erbium published in 1991"
TL;DR: Erbium-doped fiber amplifiers are modeled using the propagation and rate equations of a homogeneous two-level laser medium, and numerical methods are used to analyze the effects of optical modes and erbium confinement on amplifier performance.
Abstract: Erbium-doped fiber amplifiers are modeled using the propagation and rate equations of a homogeneous two-level laser medium. Numerical methods are used to analyze the effects of optical modes and erbium confinement on amplifier performance, and to calculate both the gain and amplified spontaneous emission (ASE) spectra. Fibers with confined erbium doping are completely characterized from easily measured parameters: the ratio of the linear ion density to fluorescence lifetime, and the absorption of gain spectra. Analytical techniques then allow accurate evaluation of gain, saturation, and noise in low-gain amplifiers (G >
1,157 citations
TL;DR: In this paper, material-dependent properties influencing the performance of fiber amplifiers are reviewed together with the available data for Er/sup 3+/. The major glass types potentially useful in this application are considered and compared to silica.
Abstract: Material-dependent properties influencing the performance of fiber amplifiers are reviewed together with the available data for Er/sup 3+/. The major glass types potentially useful in this application are considered and compared to silica. The topics addressed include quenching processes and the solubility of rare-earth ions, transition strengths and bandwidths at the 1500-nm gain transition, and the characteristics at the 800-, 980-, and 1480-nm pump bands. Aluminum is shown to be an extremely useful codopant for silica, improving its ability to dissolve rare-earth ions and providing desirable spectroscopic properties for Er/sup 3+/. For some of the attributes considered, other glasses have advantages over Al silica, but only with respect to gain bandwidth and pumping performance at 800 nm is significantly better than expected from other glass compositions. >
871 citations
TL;DR: In this paper, the effect of impurity coimplantation in MeV erbium-implanted silicon is studied and a significant increase in the intensity of the 1.54μm Er3+ emission was observed for different coimplants.
Abstract: The effect of impurity coimplantation in MeV erbium‐implanted silicon is studied. A significant increase in the intensity of the 1.54‐μm Er3+ emission was observed for different coimplants. This study shows that the Er3+ emission is observed if erbium can form an impurity complex in silicon. The influence of these impurities on the Er3+ photoluminescence spectrum is demonstrated. Furthermore we show the first room‐temperature photoluminescence spectrum of erbium in crystalline silicon.
383 citations
TL;DR: In this article, a nonlinear amplifying loop mirror was converted into a laser by feedback of the output to the input through a fiber-pigtailed optical isolator, and the pump powers were low enough that laser diodes could be used for pumping.
Abstract: A nonlinear amplifying loop mirror has been turned into a laser by feedback of the output to the input through a fibre-pigtailed optical isolator. After some optimisation, pulses as short as 314 fs were produced. The pump powers are low enough that laser diodes could be used for pumping.
320 citations
TL;DR: The first integrated optical laser in LiNbO3, doped by an indiffusion of Er3+ prior to channel-guide fabrication by Ti diffusion is reported in this article.
Abstract: The first integrated optical laser in LiNbO3, doped by an indiffusion of Er3+ prior to channel-guide fabrication by Ti diffusion is reported. Pumped by a colour centre laser (λp = 1.477 μm), CW operation at λ = 1.532 μm (Δ~0.3 nm) with a threshold of ~8 mW absorbed power was achieved.
221 citations
TL;DR: In this article, the authors reported the generation of 320fs soliton pulses at 1560nm from an all-fibre, passively mode-locked erbium fiber.
Abstract: The generation of ultrashort 320fs soliton pulses at 1560nm from an all-fibre, passively mode-locked erbium fibre is reported. Repetition rates as high as 10GHz have been observed demonstrating the device's potential as a telecommunication soliton source.
187 citations
TL;DR: In this paper, a self-starting, passively mode-locked erbium fiber laser is proposed based on the reflection properties of a nonlinear amplifying loop mirror and provides a stable source of picosecond pulses.
Abstract: A novel self-starting, passively mode-locked erbium fibre laser is reported The scheme is based on the reflection properties of a nonlinear amplifying loop mirror and provides a stable source of picosecond pulses
178 citations
TL;DR: In this article, an integrated standing-wave, single frequency, erbium fiber laser having a laser linewidth of less than 47 kHz was reported, which incorporated two highly reflective intracore Bragg reflectors which provided both cavity feedback and adequate longitudinal mode discrimination.
Abstract: An integrated standing-wave, single frequency, erbium fiber laser having a laser linewidth of less than 47 kHz is reported. The monolithic fiber laser incorporated two highly reflective intracore Bragg reflectors which provide both cavity feedback and adequate longitudinal mode discrimination. The narrow linewidth single-mode operation and monolithic construction may make this a valuable communications/sensor source. >
152 citations
TL;DR: A detailed study of the electrical and defect properties of ion-implanted erbium in silicon was performed in this paper, where the defect levels were characterized by deep level transient spectroscopy.
Abstract: A detailed study of the electrical and defect properties of ion‐implanted erbium in silicon shows that erbium doping introduces donor states. The concentration of erbium related donors as a function of implant dose saturates at 4×1016 cm−3 at a peak implanted Er‐ion concentration of (4–7)×1017 cm−3. The defect levels related to erbium in silicon are characterized by deep level transient spectroscopy and identified as E(0.09), E(0.06), E(0.14), E(0.18), E(0.27), E(0.31), E(0.32), and E(0.48). The dependence of the photoluminescence on annealing temperature for float zone and for Czochralski‐grown silicon show that oxygen and lattice defects can enhance the luminescence at 1.54 μm from the erbium. Temperature‐dependent capacitance‐voltage profiling shows donor emission steps when the Fermi level crosses EC − ET = 0.06 eV and EC − ET = 0.16 eV.
123 citations
TL;DR: In this paper, loss and gain coefficients were used to evaluate fiber performance in 980-nm or 1480-nm pumped optical amplifiers with germano-silicate core fibers.
Abstract: Erbium-doped fibers are characterized using loss and gain coefficients, and one amplifier saturation parameter. With a large-signal amplifier model that resolves the amplified spontaneous emission spectrum, these easily measured parameters allow the fiber performance in 980-nm or 1480-nm pumped optical amplifiers to be assessed rapidly. In tests at 980-nm pump wavelength, good agreement between the theoretical and experimentally measured gains was obtained with amplifiers having either germano-silicate or germano-alumino-silicate core fibers. >
114 citations
TL;DR: In this paper, the Er-doped silica guided-wave laser operating around 1.6 μm was realized using a low-scattering-loss planar lightwave circuit with an Erdoped Silica core which was fabricated by flame hydrolysis deposition and reactive ion etching techniques on an Si substrate.
Abstract: The Er-doped silica guided-wave laser operating around 1.6 μm was realised using a low-scattering-loss planar lightwave circuit with an Er-doped silica core which was fabricated by flame hydrolysis deposition and reactive ion etching techniques on an Si substrate. CW lasing was achieved successfully with an incident threshold power of 49 mW for pumping at 0.98 μm.
Patent•
31 Jul 1991TL;DR: In this paper, a wavelength demultiplexer was inserted in the Er doped optical fiber to suppress the spontaneous emission of light by spontaneous emission without causing an adverse effect on the amplification performance of the signal light.
Abstract: An optical fiber amplifier in which light generated within an Er doped optical fiber by spontaneous emission is eliminated or suppressed. By inserting a wavelength demultiplexer in the Er doped optical fiber, the light generated within the optical fiber by spontaneous emission can be effectively eliminated. As an alternative, the Er doped optical fiber is arranged in a coil form with a predetermined radius of curvature to thereby effectively eliminate light due to spontaneous emission on the longer wavelength side than the signal light. Further, by doping the center portion of the core of an optical fiber with aluminum and the whole body of the core uniformly with erbium, it is made possible to suppress the generation of light by spontaneous emission without causing an adverse effect on the amplification performance of the signal light.
TL;DR: In this paper, the temperature dependence of the gain in erbium-doped fibers between −20 and +85 degrees C was discussed. But the change in the gain was small when pumped at 0.98 mu m.
Abstract: The temperature dependence of the gain in erbium-doped fibers between -20 and +85 degrees C is discussed. The characteristics of three types of erbium-doped fibers with different erbium concentrations and glass compositions are investigated. The gain decreased with increasing temperature at the rate of -0.07 dB/ degrees C when pumped at 1.48 mu m. The change in the gain was small when pumped at 0.98 mu m. By measuring the change in the absorption and fluorescence spectra with temperature, it is deduced that the change in the gain is mainly due to the change in the saturated population inversion. >
TL;DR: Soliton propagation in a fiber described by the nonlinear Schrödinger equation in the presence of large periodic energy variations is examined and stable propagation can be achieved provided that the soliton period is long compared with the period of energy variation.
Abstract: Soliton propagation in a fiber described by the nonlinear Schrodinger equation in the presence of large periodic energy variations is examined. Stable propagation can be achieved provided that the soliton period is long compared with the period of energy variation and the (associated) average soliton (peak) pulse power equals the fundamental soliton (peak) pulse power. The result is used to interpret recent experiments on mode-locked, high-gain erbium fiber lasers.
TL;DR: In this paper, a feedback-loop scheme based on a simple feedbackloop scheme was proposed to reduce transient gain fluctuations efficiently across the whole amplifier bandwidth using only a low-power optical feedback signal.
Abstract: Dynamic compensation of low-frequency gain fluctuations in saturated erbium-doped fiber amplifiers is demonstrated. This compensation, based on a simple feedback-loop scheme makes it possible to reduce transient gain fluctuations efficiently across the whole amplifier bandwidth using only a low-power optical feedback signal. Such an, automatic gain control technique could be applied to suppress data packet interference due to traffic bursts in multiple-access networks, as well as in the implementation of long-haul fiber systems using erbium fiber amplifiers. >
TL;DR: In this article, an all fiber, diode-pumped, electrically tunable ring laser is reported. Gain is provided by an erbium-doped fiber and tuning by a fibre Fabry-Perot etalon.
Abstract: An all fibre, diode-pumped, electrically tunable ring laser is reported. Gain is provided by an erbium-doped fibre and tuning by a fibre Fabry-Perot etalon. The threshold at l.566 μm is 2.9mW, the slope efficiency is 0.15 and the output power is 4.2 mW with 32 mW of pump power. The output wavelength can be tuned from 1.525 to 1.586 μm with a variation in power of less than 3.5 dB.
TL;DR: In this article, an actively mode-locked erbium-doped ring laser with birefringent polarisation-maintaining fiber was used to produce dual pulses with different peak wavelengths and durations as short as 2ps.
Abstract: Dual pulses each with different peak wavelengths and durations as short as 2ps were concurrently produced with an actively mode-locked erbium-doped fibre ring laser made in part with birefringent polarisation-maintaining fibre. Peak wavelength separations measured in the experiment agreed well with the theoretical values.
TL;DR: In this paper, a mode-locked erbium fiber laser with self-sustaining, picosecond duration pulses which are not at the modulation frequency of 480 MHz have been observed.
Abstract: Novel behaviour from an FM mode-locked erbium fibre laser is reported. Selfsustaining, picosecond duration pulses which are not at the modulation frequency of 480 MHz have been observed. The pulses form complex pulse trains and seem to experience soli ton interactions, causing them to execute complicated motions.
TL;DR: In this paper, the erbium-doped fiber laser cavity configuration was used to produce single-longitudinal mode operation with less than 10 kHz linewidth, which prevents spatial hole burning from occurring.
Abstract: We report a novel erbium-doped fibre laser cavity configuration which produces single-longitudinal-mode operation with less than 10kHz linewidth. The fibre loser operates in a travelling-wave mode which prevents spatial holeburning from occurring. A principal advantage of the configuration is that it allows the precise and stable setting of the lasing wavelength.
TL;DR: It is shown that it is possible to achieve all-optical switching, amplification, and compression of short pulses in a single device.
Abstract: A numerical study of the all-optical switching properties of solitons in an erbium-doped nonlinear fiber coupler is presented. The small gain provided by the erbium both lowers and sharpens the switching threshold, while producing pulse-compression factors of 3 to 9. As a result, we show that it is possible to achieve all-optical switching, amplification, and compression of short pulses in a single device.
TL;DR: Though the basic nature of the erbium magnetic order is not qualitatively altered in either the thin films or superlattices, the conical ferromagnetic phase is suppressed in all of the samples considered and the enhanced critical fields exhibit a systematic dependence on Er-layer thickness.
Abstract: Crystalline erbium thin films and Er/Y superlattices with varying Er-layer thicknesses have been grown by molecular-beam epitaxy. The magnetic and structural properties of these samples have been analyzed by x-ray-scattering, bulk-magnetization, and neutron-diffraction techniques. From a comparison of the data for the two systems, the importance of interfacial strain relative to artificial modulation in shaping the magnetic behavior has been determined. Though the basic nature of the erbium magnetic order is not qualitatively altered in either the thin films or superlattices, the conical ferromagnetic phase is suppressed in all of the samples considered. The enhanced critical fields exhibit a systematic dependence on Er-layer thickness. These effects appear to follow directly from the epitaxial basal-plane strain which is measurable in films over 14 000 \AA{} thick. This strain, along with a ``clamping'' of the Er thermal expansion to the Y lattice, leads to a reduction of the magnitude of the magnetoelastic energy that drives the ferromagnetic transition. The dependence of the magnetoelastic energy on the epitaxial strain is described by a model which accounts for the elastic coupling of the erbium lattice to the yttrium.
TL;DR: In this paper, an erbium doped fiber ring laser with singlemode operation over a continuous wavelength tuning range of 44 nm (1528nm-1572nm) with laser linewidths of less than 10 kHz is reported.
Abstract: An erbium doped fibre ring laser enabling singlemode operation over a continuous wavelength tuning range of 44 nm (1528nm–1572nm) with laser linewidths of less than 10kHz is reported.
TL;DR: In this article, the erbium-doped InP layers were observed to have a 1.54 μm luminescence peak at 1.543 μm, and the fine structure of the peak was also different from that of photoluminescence.
Abstract: The Er‐related 1.54 μm luminescence peak has been observed in erbium‐doped InP layers by impact excitation of Er atoms with energetic carriers accelerated by electric field. Er ions were implanted into n‐type InP and Au/Sn ohmic contacts were formed on top of the surface. The Er‐related sharp peak at 1.543 μm was observed by only applying dc voltages between the electrodes over the temperature range from 77 to 360 K. Neither band‐edge emission nor impurity‐related emission were observed, although they were intense in the photoluminescence spectra of the same sample. The fine structure of the 1.54 μm peak was also different from that of photoluminescence. This 1.54 μm emission was related to erbium atoms excited through collisions with energetic electrons accelerated by the electric field.
TL;DR: In this article, the luminescence properties of semiconducting zinc oxide doped with neodymium, erbium, europium and dysprosium have been investigated.
18 Feb 1991
TL;DR: In this paper, the performance of a multi-kilometer, low-erbium-concentration fiber amplifier made by the modified chemical vapor deposition (MCVD) seed fiber method is discussed.
Abstract: Continued improvements in the performance of a multi-kilometer, low-erbium-concentration fiber amplifier made by the modified chemical vapor deposition (MCVD) seed fiber method are discussed. Transparency for a -20-dBm signal at 1.55 mu m and fiber length of 11.8 km was achieved with 20 mW of 1.48- mu m copropagating pump power. The wavelength dependence of the gain for this signal level is reported, and the distribution in small signal gain along a 22-km length using an optical domain reflectometer (OTDR) was measured. Simulations are presented to show the effect of erbium concentration, input signal level, and pump power required for transparency of a 50-km span. >
TL;DR: A fiber amplifier model is developed which includes a finite lifetime for the pumped level which is solved numerically for a erbiumdoped fiber amplifier pumped at 980 nm.
Abstract: A fiber amplifier model is developed which includes a finite lifetime for the pumped level. Pump excited state absorption (ESA) from the pumped level is also included. The model is solved numerically for a erbiumdoped fiber amplifier pumped at 980 nm. The signal output power at 1.5 microm is found to be limited by the finite lifetime of the (4)I(11/2); ESA of the pump from the (4)I(11/2) further limits the signal output. Lifetimes of the (4)I(11/2) were measured for Er(3+) in a series of oxide and fluoride glasses. Output saturation is most important in the fluoride based glasses, where the (4)I(11/2) lifetime is longest.
TL;DR: In this article, the mode-locked operation of a diode-pumped erbium doped fiber laser is described in which an optically written fibre Bragg reflection grating is used to define the operating wavelength.
Abstract: Mode-locked operation of a diode-pumped erbium doped fibre laser is described in which an optically written fibre Bragg reflection grating is used to define the operating wavelength. Pulses of 35 ps duration have been generated at a repetition rate of 5 GHz with mean (peak) output powers of 5mW(29mW).
Patent•
04 Dec 1991TL;DR: In this paper, an erbium-to-silicon active core with an atomic ratio of at least about 0.01 and an absolute erbiam concentration of 1.4×1020 atoms per cubic centimeter was presented.
Abstract: An active optical device comprises a glass, waveguiding structure disposed on a substantially planar principal surface of a substrate. The structure includes a silica-based, erbium-doped active core. The active core has an erbium-to-silicon atomic ratio of at least about 0.01, an absolute erbium concentration of at least about 1.4×1020 atoms per cubic centimeter, and a radiative lifetime of the erbium lasing level of at least about 7 milliseconds. Also disclosed is a method for forming an active optical device, including the step of depositing an erbium-doped active core by sputtering.
TL;DR: In this article, an economical method for combining erbium-doped fiber (EDF) amplifiers and star couplers is presented, which involves simultaneously pumping EDFs placed at the input or output ports of the coupler with a single laser pump source distributed through coupler itself.
Abstract: An economical method for combining erbium-doped fiber (EDF) amplifiers and star couplers, is presented. It involves simultaneously pumping EDFs placed at the input or output ports of the coupler with a single laser pump source distributed through the coupler itself. In this way, many amplifiers can share the cost of a single pump laser, and the need for individual pump/signal combiners is eliminated. >
NEC1
TL;DR: In this article, an erbium doped fiber (EDF) preamplifier with a 0.98 mu m laser diode was used to achieve an extremely high receiver sensitivity at 10 Gb/s.
Abstract: The authors report the realization of an extremely high receiver sensitivity at 10 Gb/s by using an erbium doped fiber (EDF) preamplifier pumped with a 0.98 mu m laser diode. The obtained EDF input sensitivity is -37.2 dBm (147 photons/bit). In addition, the importance of minimizing reflection from amplifier fiber ends is shown. >