Showing papers on "Erbium published in 1997"
TL;DR: The role of implantation defects, the effect of annealing, concentration dependent effects, and optical activation are discussed and compared for different Er-doped thin film photonic materials.
Abstract: Erbium doped materials are of great interest in thin film integrated optoelectronic technology, due to their Er3+ intra-4f emission at 1.54 μm, a standard telecommunication wavelength. Er-doped dielectric thin films can be used to fabricate planar optical amplifiers or lasers that can be integrated with other devices on the same chip. Semiconductors, such as silicon, can also be doped with erbium. In this case the Er may be excited through optically or electrically generated charge carriers. Er-doped Si light-emitting diodes may find applications in Si-based optoelectronic circuits. In this article, the synthesis, characterization, and application of several different Er-doped thin film photonic materials is described. It focuses on oxide glasses (pure SiO2, phosphosilicate, borosilicate, and soda-lime glasses), ceramic thin films (Al2O3, Y2O3, LiNbO3), and amorphous and crystalline silicon, all doped with Er by ion implantation. MeV ion implantation is a technique that is ideally suited to dope these materials with Er as the ion range corresponds to the typical micron dimensions of these optical materials. The role of implantation defects, the effect of annealing, concentration dependent effects, and optical activation are discussed and compared for the various materials.
1,089 citations
TL;DR: Erbium-doped multicomponent phosphate glass waveguides were deposited by rf sputtering techniques in this paper, and a net optical gain of 4.1 dB at 1.535 μm was achieved.
Abstract: Erbium-doped multicomponent phosphate glass waveguides were deposited by rf sputtering techniques. The Er concentration was 5.3×1020 cm−3. By pumping the waveguide at 980 nm with a power of ∼21 mW, a net optical gain of 4.1 dB at 1.535 μm was achieved. This high gain per unit length at low pump power could be achieved because the Er–Er cooperative upconversion interactions in this heavily Er-doped phosphate glass are very weak [the upconversion coefficient is (2.0±0.5)×10−18 cm3/s], presumably due to the homogeneous distribution of Er in the glass and due to the high optical mode confinement in the waveguide which leads to high pump power density at low pump power.
296 citations
TL;DR: Er3+-doped tellurite singlemode fiber is fabricated and signal amplification and laser oscillation are demonstrated for the first time in this article, where a small signal gain of 16 dB at 1560 nm is obtained for a pump power of 130 mW at 978 nm.
Abstract: Er3+-doped tellurite singlemode fibre is fabricated and signal amplification and laser oscillation are demonstrated for the first time. A small-signal gain of 16 dB at 1560 nm is obtained for a pump power of 130 mW at 978 nm. A laser oscillation is observed with a threshold pump power of 120 mW at 978 nm and a slope efficiency of 0.65% using this fibre.
294 citations
TL;DR: In this article, a silica-based erbium doped fiber amplifier (EDFA) with a flat gain bandwidth exceeding 40 nm is described, and the dual-stage EDFA includes a precisely designed inter-stage long-period fiber grating filter with more than 14dB peak attenuation.
Abstract: Broad-bandwidth amplification is essential for the construction of high-capacity multichannel communication systems. We describe a silica-based erbium doped fiber amplifier (EDFA) with a flat gain bandwidth exceeding 40 nm. The dual-stage EDFA includes a precisely designed inter-stage long-period fiber grating filter with more than 14-dB peak attenuation. By careful choice of the filter spectrum and fiber lengths, this EDFA is flat to within 1 dB over 40 nm while producing a noise figure below 4.0 dB and nearly +15-dBm output power.
248 citations
TL;DR: In this paper, the authors studied the dependence of erbium-doped fiber amplifier performance on the ion concentration and found that the quantum efficiency of the amplifier is strongly dependent on ion concentration, signal wavelength, and the relative propagation direction of the pump and signal beams.
Abstract: The dependence of erbium-doped fiber amplifier (EDFA) performance on the erbium ion concentration is studied experimentally and theoretically. The quantum efficiency of the amplifier is found to he strongly dependent on the erbium ion concentration, the signal wavelength, and the relative propagation direction of the pump and signal beams. This dependence is fully explained by the presence of an upconversion mechanism between ions residing in pairs or larger clusters and suggests that other sources of amplifier performance degradation (back-ground loss, excited state absorption, homogenous upconversion) are negligible. The experimental data show that in the present EDFA designs with over 80% quantum/conversion efficiency, the aluminum co-doped fibers with erbium ion concentration less than 20/spl times/10/sup 24/ m/sup -3/ (900 molar ppm Er/sup 3+/) are most suitable.
213 citations
TL;DR: In this article, a near-infrared luminescent ytterbium (III), neodymium(III) and erbium-III chelates containing organic chromophores derived from fluorescein and eosin have been synthesized and studied spectroscopically.
193 citations
21 Jul 1997
TL;DR: Traveling-wave amplification of alambda = 1.53 microm signal with +22-dB gain is achieved at 295 K in an Er(3+)-doped single-mode fiber using a lambda = 514.5 nm pump source.
Abstract: Traveling-wave amplification of a lambda = 1.53 microm signal with +22-dB gain is achieved at 295 K in an Er(3+)-doped single-mode fiber using a lambda = 514.5 nm pump source. The optimum fiber length for maximum gain is determined experimentally. A limit in signal-to-noise ratio that is due to concurrent amplification of spontaneous emission is observed. By cooling the fiber to 77 K, the amplifier gain is increased to +29 dB as a result of depopulation of the lower laser level.
171 citations
TL;DR: In this article, a two-band erbium-doped silica fiber amplifier with a record optical bandwidth of 80 nm is presented, where the two bands share a common first gain section and have distinct second gain sections.
Abstract: The authors demonstrate a two band architecture for an ultrawideband erbium-doped silica fibre amplifier with a record optical bandwidth of 80 nm. To obtain a low noise figure and high output power, the two bands share a common first gain section and have distinct second gain sections.
152 citations
TL;DR: In this paper, the authors report the successful system demonstration of a four-wavelength integrated-optics amplifying combiner, which consists of an all-connectorized 4/spl times/1 glass splitter followed by a 4.5 cm-long Er/Yb-doped waveguide amplifier.
Abstract: We report the successful system demonstration of a four-wavelength integrated-optics amplifying combiner. The arrangement consists of an all-connectorized 4/spl times/1 glass splitter followed by a 4.5-cm-long Er/Yb-doped waveguide amplifier. When injecting 120 mW of 975-nm laser diode pump, we record, in the amplifying section, 11.6 dB of net gain in the single pass configuration and 23 dB in the double pass as well as a noise figure of 4.5 dB. These results show the potentiality of ion-exchange technology for the fabrication of lossless telecommunication devices.
122 citations
TL;DR: In this article, a short cavity erbium/ytterbium fiber laser with a saturable Bragg reflector is presented, which produces sub-500-fs pulses at fundamental cavity repetition rates as high as 300 MHz.
Abstract: We present short cavity erbium/ytterbium fiber lasers that are passively mode-locked with a saturable Bragg reflector. The lasers produce sub-500-fs pulses at fundamental cavity repetition rates as high as 300 MHz. Stable passive harmonic operation increases the repetition rate to 2.0 GHz. The mode-locking mechanism in both the normal and anomalous group velocity dispersion regimes is investigated using complete analytical and numerical models and direct comparison with the experimental results. A simple technique for accurately measuring the total cavity dispersion is presented.
120 citations
TL;DR: In this article, two schemes for wavelength conversion based on the cascading of two successive second order processes in a quasi-phase-matched lithium niobate channel waveguide were investigated.
Abstract: We investigate two schemes for wavelength conversion based on the cascading of two successive second order processes in a quasi-phase-matched lithium niobate channel waveguide. Efficient conversion over the full erbium amplifier bandwidth is possible with a single multi-hundred milliwatt pump laser operating around 1.55 μm.
TL;DR: The infrared emission spectroscopy of erbium doped glasses and fibres shows the potential of this glass host for rare-earth doped, mid-infrared fibre lasers, for gas sensing, atmospheric transmission, and medical applications.
Abstract: Gallium lanthanum sulphide based glasses are proposed as high quality hosts for rare-earth doped, mid-infrared fibre lasers, that would offer compact and rugged sources for gas sensing, atmospheric transmission, and medical applications. The infrared emission spectroscopy of erbium doped glasses and fibres shows the potential of this glass host for the above applications. Mid-infrared transitions at 2.0, 2.75, 3.6, and 4.5μm have been detected and characterized.
Patent•
08 Sep 1997TL;DR: In this paper, an electronic sweep waveform is used to frequency modulate the acoustic signal produced by the acousto-optic modulator, which provides a broader spectral width, on the order of 19 nm.
Abstract: A laser source comprises an optical fiber doped with a homogeneously broadened lasing medium, preferably with Erbium, pumped by a laser pump source and an intracavity acousto-optic modulator. When the acousto-optic modulator is driven by a variable frequency source, the Erbium fluorescence line emitted by the Erbium-doped optical fiber can be electronically tuned. In another embodiment, an electronic sweep waveform is used to frequency modulate the acoustic signal produced by the acousto-optic modulator. Without the low-rate frequency modulation, Erbium in a silica optical fiber is a mostly homogeneously broadened gain medium with a narrow laser linewidth. When measured on a long time scale, low-rate frequency modulation provides a broader spectral width, on the order of 19 nm, which makes such a source an ideal source for certain optical applications such as fiber optic gyroscopes.
TL;DR: In this article, a pigtailed erbium-ytterbium codoped planar glass waveguide amplifier module with a single 980-nm diode pump is presented.
Abstract: We report the full characterization of a pigtailed erbium-ytterbium codoped planar glass waveguide amplifier module. With a single 980-nm diode pump, this ion-exchanged 4.5-cm-long device delivers a signal gain of 16.5 dB, a noise figure of 5 dB, and a saturated output power of 12.5 dBm. To verify its practicality and stability, we tested this module as a power booster in a 10 Gb/s transmission system experiment at the 1534 nm wavelength, and demonstrated the successful bit-error-rate (BER<10/sup -12/) transmission over 72.5 km of dispersion shifted fiber.
TL;DR: In this paper, an ideal phase-locked-loop (PLL) operation of a 10 GHz erbium doped fiber laser has been achieved by using a voltage controlled regenerative modelocking technique.
Abstract: Ideal phase-locked-loop (PLL) operation of a 10 GHz erbium doped fibre laser has been achieved for the first time by using a voltage controlled regenerative modelocking technique. The repetition rate of the regeneratively modelocked fibre laser in a free running condition can be continuously varied by changing the voltage supplied to the PZT to change the fibre cavity length. PLL operation is achieved by feeding back a phase sensitive error signal to the PZT. This signal is obtained by mixing a laser clock signal with a synthesizer signal. The external signal tracking range is 40 kHz.
TL;DR: In this article, the effects of cavity components and operating parameters on laser stability and output pulse characteristics were analyzed for a harmonically modelocked erbium fiber ring laser stabilized by an intracavity bit-rate etalon.
Abstract: We present both experimental and theoretical investigations of the operation of a harmonically modelocked erbium fiber ring laser stabilized by an intracavity bit-rate etalon. Our model analyzes the effects of cavity components and operating parameters on laser stability and output pulse characteristics. The model predicts the output pulsewidth variation with laser cavity parameters such as cavity length, dispersion, and finesse of intracavity Fabry-Perot etalons. If the laser cavity length is not optimized, a maximum 50% increase in pulsewidth can occur at 5 Gb/s pulse rate. A repetition rate etalon with a finesse of 50 is sufficient to provide a side-mode suppression ratio of over 50 dB in the laser output. We also discuss how detuning from the optimal modulation frequency increases the excess noise that affects the laser stability. The theory predicts a maximum detuning range of /spl plusmn/100 kHz, which agrees with the experimental observations. These theoretical results can guide the design of similar lasers over a wide range of operating parameters.
Patent•
03 Oct 1997
TL;DR: In this article, an optical fiber amplifier is constituted by serially connecting a second optical fiber 2 on the light emitting end side of a first optical fiber 1 formed by an erbium (Er) doped optical fiber.
Abstract: PROBLEM TO BE SOLVED: To provide an optical fiber amplifier small in wavelength dispersion in a wavelength band being used SOLUTION: The optical fiber amplifier is constituted by serially connecting a second optical fiber 2 on the light emitting end side of a first optical fiber 1 formed by an erbium (Er) doped optical fiber and connecting an excitation light source laser diode LD6 to the emitting end side of a second optical fiber 2 through a connecting optical fiber 3 and a wavelengthdivisionmultiplex(WDM) coupler 5 The fiber 2 is formed out of an optical fiber in which the code of the wavelength dispersion in the wavelength band being used by an optical fiber amplifier differs from the code of the wavelength dispersion of the fiber 1 in the same wavelength band Thus, the wavelength dispersion of the fiber 1 is canceled by the wavelength dispersion of the fiber 2 Note that a ratio L2 /L1 , where L1 and L2 are the lengths of the fibers 1 and 2, is approximately set equal to a ratio D1a /D2a where D1a and D2a are the absolute values of the wavelength dispersion values of the fibers 1 and 2, respectively
TL;DR: Erbium LIII-edge x-ray absorption fine structure (XAFS) and 4I13/2 excited state lifetime measurements were performed on aluminosilicate, fluorosilicates, and phosphate glasses with varying erbium concentration as discussed by the authors.
Abstract: Erbium LIII-edge x-ray absorption fine structure (XAFS) and 4I13/2 excited state lifetime measurements were performed on aluminosilicate, fluorosilicate, and phosphate glasses with varying erbium concentration. The local erbium environment is shown to be unique in each host. In the aluminosilicate, erbium is found to have 6.4 nearest oxygen neighbors at a distance of 2.22 A and with a Debye–Waller factor of 0.031 A2. Erbium in the fluorosilicate glass was found to be more highly coordinated with 7.5 nearest neighbor anions. Erbium in the phosphate glass is found to have a smaller disorder factor of 0.021 A2 when compared with the silicate glasses. No variation of the environment (3 shells) is observed with changes in rare earth concentration, while the excited state lifetime varies from 1.0 to 9.8 ms in the aluminosilicates, suggesting the absence of erbium clustering at XAFS detectable distances.
TL;DR: In this article, a high power Q-switched erbium doped fiber laser is demonstrated using a novel, large mode area, single transverse mode fibre. But the results represent the highest peak powers obtained from an actively Q-Switched erbiium doping fiber laser.
Abstract: A high power Q-switched erbium doped fibre laser is demonstrated using a novel, large mode area, single transverse mode fibre. Peak powers in excess of 4 kW, and pulsewidths of 10 ns are reported at a repetition rate of 500 Hz. These results represent the highest peak powers obtained from an actively Q-switched erbium doped fibre laser.
TL;DR: In this article, the photoluminescence of hydrogenated amorphous silicon with small amounts of erbium (Er/Si concentration ∼5 at. %) was prepared by radio frequency sputtering from a Si target partially covered by tiny metallic Er chunks.
Abstract: Hydrogenated amorphous silicon with small amounts of erbium (Er/Si concentration ∼5 at. %) was prepared by radio frequency sputtering from a Si target partially covered by tiny metallic Er chunks. Four sets of samples were studied: nonintentionally contaminated hydrogenated and nonhydrogenated amorphous silicon-erbium (a-SiEr:H and a-SiEr); nitrogen doped a-SiEr(N):H and oxygen contaminated a-SiEr(O):H. Samples from the first two sets present only faint 1.54 μm photoluminescence characteristic from Er3+ ions even at 77 K. Samples from the other sets show this luminescence at 77 K as deposited, without any further annealing step. Thermal annealing up to 500 °C increases the photoluminescence intensity, and room temperature emissions become strong enough to be easily detected. These results indicate that in an amorphous silicon environment the chemical neighborhood of the Er3+ ions is crucial for efficient 1.54 μm emission. Raman scattering from both as-deposited and annealed samples showed that network dis...
TL;DR: The McCumber theory was used to derive the emission cross section spectrum from the absorption results, which was then compared with the Er(3+) photoluminescence spectrum to predict the optical gain performance of an Er-doped Al(2)O(3) optical amplifier that operates around 1.5 mum.
Abstract: Al(2)O(3) slab waveguide films were doped with erbium using ion implantation to a peak concentration of 1.5 at. %. Prism coupling measurements show absorption caused by (4)I (15/2) ?(4)I (13/2) intra-4f transitions in Er(3+) with a maximum at 1.530 mum of 8 dB/cm. The Er(3+) absorption cross section is determined as a function of wavelength. We used the McCumber theory to derive the emission cross section spectrum from the absorption results, which we then compared with the Er(3+) photoluminescence spectrum. The peak absorption and emission cross sections are found to be 6 x 10(-21) cm(-2). The results are used to predict the optical gain performance of an Er-doped Al(2)O(3) optical amplifier that operates around 1.5 mum.
TL;DR: In this paper, a rate-equation analysis of the erbium 3/spl mu/m ZBLAN fiber laser is performed, which considers ground-state bleaching, excited-state absorption (ESA), interionic processes, lifetime quenching by co-doping, and stimulated emission at 2.7 /spl µ/m and 850 mn.
Abstract: A rate-equation analysis of the erbium 3-/spl mu/m ZBLAN fiber laser is performed. The computer calculation includes the longitudinal spatial resolution of the host material. It considers ground-state bleaching, excited-state absorption (ESA), interionic processes, lifetime quenching by co-doping, and stimulated emission at 2.7 /spl mu/m and 850 mn. State-of-the-art technology including double-clad diode pumping is assumed in the calculation. Pump ESA is identified as the major problem of this laser. With high Er/sup 3+/ concentration, suitable Pr/sup 3+/ co-doping, and low pump density, ESA is avoided and a diode-pumped erbium 3-/spl mu/m ZBLAN laser is predicted which is capable of emitting a transversely single-mode output power of 1.0 W when pumped with 7-W incident power at 800 nm. The corresponding output intensity which is relevant for surgical applications will be in the range of 1.8 MW/cm/sup 2/. Compared to Ti:sapphire-pumped cascade-lasing regimes, the proposed approach represents a strong decrease of the requirements on mirror coatings, cavity alignment, and especially pump intensity. Of the possible drawbacks investigated in the simulation, only insufficient lifetime quenching is found to have a significant influence on laser performance.
TL;DR: In this article, a thin Er2O3 layer grown on a Si surface by vapor doping of Er exhibits intense photoluminescence in the green and red regions excited by laser beams in the 800 nm and 450-490 nm ranges.
Abstract: A thin Er2O3 layer grown on a Si surface by vapor doping of Er exhibits intense photoluminescence in the green and red regions excited by laser beams in the 800 nm and 450–490 nm ranges. These intense light emissions take place via resonant two or one step photoexcitations of the 4f levels in Er3+ ions. Our sample fabrication procedure is integrated circuit compatible and produces Er2O3 layers of excellent homogeneity and quality as demonstrated in the optical measurements.
TL;DR: In low temperature studies of ultrapure erbium (and dysprosium) as discussed by the authors, the authors have discovered unusual thermal effects at the first order magnetic transformation, including superheating (i.e., the metal is colder after heat has been added to it than before the heat pulse).
Abstract: In low temperature studies of ultrapure erbium (and dysprosium) we have discovered unusual thermal effects at the first order magnetic transformation of erbium ({congruent} 19K). These include (1)superheating (i.e., {ital the metal is colder after heat has been added to it than before the heat pulse }), (2)supercooling, and (3)the existence of metastable intermediate phases during this phase transformation in erbium (four on heating and two on cooling). In comparison, dysprosium exhibits both superheating and supercooling, but no intermediate metastable phases are observed. Furthermore, none of these effects are observed in less pure metals. {copyright} {ital 1997} {ital The American Physical Society}
TL;DR: In this article, lifetime characteristics of fluorescence, over the wavelength region ∼1.5 μm from pumped Er-doped fibers of various activator concentrations, at temperatures up to ∼950 ˚C, have been carried out and a significant variation of the fluorescence lifetimes with temperature was seen.
Abstract: An investigation of lifetime characteristics of fluorescence, over the wavelength region ∼1.5 μm from pumped Er-doped fibers of various activator concentrations, at temperatures up to ∼950 °C, has been carried out and a significant variation of fluorescence lifetimes with temperature was seen. The results have an impact upon the use of laser or stimulated emission processes at much higher temperatures and for lifetime-based, fiber-optic temperature sensors, showing a very favorable characteristic for such latter applications.
TL;DR: In this article, a defect-related Auger excitation mechanism for electronic excitation of erbium ions in the amorphous matrix is proposed, which is based on defect-sensitive Auger activation.
Abstract: We have observed strong room-temperature electroluminescence at 1.54 μm induced by erbium ions in amorphous hydrogenated silicon (a-Si:H). The device consisted of an Al/a-Si:H(Er)/n-c-Si/Al structure. A mechanism for electronic excitation of the erbium ions in the amorphous matrix is proposed that is based on defect-related Auger excitation.
TL;DR: In this article, the authors demonstrated the 1.5 μm electroluminescence from implanted Er ions inside the SiO2 insulator of a silicon metal-oxide-semiconductor structure under forward bias.
Abstract: We have demonstrated the 1.5 μm electroluminescence from implanted Er ions inside the SiO2 insulator of a silicon metal-oxide-semiconductor structure under forward bias. The Er ions are excited by the direct impact from electrons tunneling through the oxide at electric fields larger than 6 MV/cm. Under these conditions, we measured an excitation cross-section of 6±2×10−15 cm2 and a lifetime of the excited 4I13/2 level of 1.5 ms.
TL;DR: In this paper, stable simultaneous lasing of up to 29 wavelengths in miniature 1-and 2-mm-long Er/sup 3+/:Yb/sup-3+/ fiber Fabry-Perot lasers is demonstrated.
Abstract: We demonstrate stable simultaneous lasing of up to 29 wavelengths in miniature 1- and 2-mm-long Er/sup 3+/:Yb/sup 3+/ fiber Fabry-Perot lasers. The wavelengths are separated by 0.8 (100 GHz) and 0.4 nm (50 GHz), respectively, corresponding to the free spectral range of the laser cavity. The number of lasing wavelengths and the power stability of the individual modes are greatly enhanced by cooling the laser in liquid nitrogen (77 K). The polarization modes and linewidth of each wavelength are measured with high resolution by heterodyning with a local oscillator. The homogeneous linewidth of the Er/sup 3+/:Yb/sup 3+/ fiber at 77 K is determined to be /spl sim/0.5 nm, from spectral-hole-burning measurements, which accounts for the generation of a stable multiwavelength lasing comb with wavelength separations of 0.4 nm.
TL;DR: The electroluminescence behavior of erbium-oxygen-doped silicon light emitting diodes grown by molecular beam epitaxy was studied for a fixed oxygen-to-erbium concentration ratio of about six as discussed by the authors.
Abstract: The electroluminescence behavior of erbium-oxygen-doped silicon light emitting diodes grown by molecular beam epitaxy was studied for a fixed oxygen to erbium concentration ratio of about six. The diodes were operated in reverse bias. An increase of the erbium and oxygen content leads to a stronger erbium intensity at 5 K up to an erbium concentration of 1.5×1020 cm−3, an enhanced decrease of the erbium intensity with higher temperatures, and a shift of the temperature quenching onset to lower temperatures. The strongest erbium electroluminescence emission in reverse bias in this set of samples was obtained from annealed Si:Er-diodes doped with concentrations of 5×1019, or 1.5×1020 cm−3 erbium and 3×1020 or 3×1021 cm−3 oxygen, respectively. Electroluminescence emission due to erbium was detected up to 440 K.
TL;DR: In this paper, a new approach to produce structured optical materials is described, which relies on the capability of growing eutectic crystals of wide optical band gap materials by directional solidification procedures.
Abstract: A new approach to produce structured optical materials is described. The method relies on the capability of growing eutectic crystals of wide optical band gap materials by directional solidification procedures. The laser float zone technique was used to produce ordered arrays of alternate lamellae with thickness of the order of microns of erbium doped CaZrO3 and calcia stabilized zirconia single crystals. The later, having a higher refractive index, exhibited planar waveguiding effects as it has been proved experimentally. The possibility of producing waveguides from eutectic crystals promises the fabrication of hundreds of planar waveguides integrated into a crystal grown at a speed of several tenths of cm/h.