Showing papers on "Erbium published in 1993"
Book•
01 Jan 1993
TL;DR: The theory of operation of laser fiber devices and amplifiers has been studied in this paper, where the authors describe the properties of rare earth doped fiber fabrication and its physical properties.
Abstract: Rare earth doped fibre fabrication - techniques and physical properties, Jay R Simpson optical and electronic properties of rare earth ions in glasses, Wiliam J Miniscalco devices and configurations for fibre laser sources and amplifiers, Paul Urquhart theory of operation of laser fibre devices, Michael JF Digonnet Nd3+- and Er3+-doped silica fibre lasers, Michael JF Digonnet and E Snitzer narrow line width and tunable fibre lasers, PR Morkel broadband operation of erbium- and neodymium-doped fibre sources, Paul F Wysocki Q-switched fibre lasers, WL Barnes mode-locked fibre lasers, Mark W Phillips rare earth doped heavy-metal fluoride glass fibres, JS Sanghera and ID Aggarwal erbium-doped fibre amplifiers - basic physics and characteristics, E Desurvire applications of fibre amplifiers to telecommunications systems, Noboru Edagawa
837 citations
CNET1
TL;DR: In this article, it was shown that in low-concentration erbium-doped silicate fibers (below 1000 p.p.m.), a residual absorption at 980 nm cannot be saturated.
Abstract: It is shown that in low-concentration erbium-doped silicate fibers (below 1000 p.p.m.), a residual absorption at 980 nm cannot be saturated. Usual models for upconversion of Er/sup 3+/ cannot match this behavior nor explain a fluorescence lifetime independent of pump power and erbium concentration. A phenomenon, the pair induced quenching (PIQ), that is compatible with the previous experimental results is exhibited. The influence of erbium and aluminum concentration on the ion pair proportion is shown. >
240 citations
TL;DR: In this article, an erbium fiber amplifier with a highly flattened gain spectrum was demonstrated using an all-fibre photosensitive Bragg grating, achieving an ASE spectrum flattened to within ± 0.5 dB over a bandwidth of 35 nm in the 1550 nm window.
Abstract: An erbium fibre amplifier with a highly flattened gain spectrum is demonstrated for the first time using an all fibre photosensitive Bragg grating. An ASE spectrum flattened to within ±0.5 dB over a bandwidth of 35 nm in the 1550 nm window is achieved with a 3 mm long radiation coupling Bragg fibre grating.
155 citations
TL;DR: By using a new simple cavity design, in which both linear and nonlinear polarization evolution are reproducibly controlled, passive mode locking in a Fabry–Perot-type erbium fiber laser is demonstrated.
Abstract: By using a new simple cavity design, in which both linear and nonlinear polarization evolution are reproducibly controlled, we demonstrate passive mode locking in a Fabry–Perot-type erbium fiber laser. The laser generates stable trains of pulses as short as 200 fs with an energy content of 70 pJ at repetition rates as high as 100 MHz.
154 citations
TL;DR: In this paper, the authors report the fabrication of a short, robust, single-mode Er/sup 3+/ fiber-grating laser, which is proven by the successful outcome of a long-term bit-error-rate test at the 10/sup -15/ level in a 5 G/s fiber transmission experiment.
Abstract: In this paper we report the fabrication of a short, robust, single-mode Er/sup 3+/ fiber-grating laser. This laser is proven by the successful outcome of a long-term bit-error-rate test at the 10/sup -15/ level in a 5- G/s fiber transmission experiment. In the process we present a new pumping geometry, the elucidation of one origin of relaxation oscillations that have plagued previous lasers and the demonstration of a simple electronic feedback scheme for suppressing them. This prototype source shows real promise for use in a high-speed communications system. >
148 citations
Patent•
19 May 1993TL;DR: In this paper, a laser is fabricated from an optical transmission medium having a laser cavity with an rare earth (e.g. Erbium) doped portion, and at least one longitudinal mode is suppressed using a plurality of series coupled Fabry-Perot cavities, an optical grating, or a combination thereof.
Abstract: A laser is fabricated from an optical transmission medium having a laser cavity with an rare earth (e.g. Erbium) doped portion. At least one longitudinal mode is suppressed using a plurality of series coupled Fabry-Perot cavities, an optical grating, or a combination thereof. Ring lasers, Sagnac cavity lasers, Fox-Smith cavity lasers, and linear structures are disclosed.
131 citations
TL;DR: A low-threshold, high-conversion-efficiency erbium-doped fiber laser in a 100-parts-in-106 fiber pumped at 1.48 μm is reported, and through modeling it is shown that the cluster content increases with concentration.
Abstract: We report a low-threshold, high-conversion-efficiency erbium-doped fiber laser in a 100-parts-in-106 fiber pumped at 1.48 μm. The threshold and efficiency are found to deteriorate noticeably as the erbium concentration is increased. We propose that this is due mostly to rapid cross relaxation between ion pairs or clusters, and through modeling we show that the cluster content increases with concentration.
128 citations
TL;DR: By writing several loss-inducing photosensitive side-tap Bragg gratings in a short length of optical fibre, the gain variation of ±1.6 dB over a bandwidth of 33 nm in a saturated erbium doped fiber amplifier is reduced to ±0.3 dB as mentioned in this paper.
Abstract: By writing several loss-inducing photosensitive side-tap Bragg gratings in a short length of optical fibre, the gain variation of ±1.6 dB over a bandwidth of 33 nm in a saturated erbium doped fibre amplifier is reduced to ±0.3 dB. It is shown for the first time that these gratings may be written with predictable ease.
112 citations
TL;DR: In this article, an all-polarisation preserving actively modelocked erbium doped fiber ring laser was used to generate optical pulses of less than 6ps duration at repetition rates up to 40GHz.
Abstract: Optical pulses of less than 6ps duration have been generated at repetition rates up to 40GHz using an all-polarisation preserving actively modelocked erbium doped fibre ring laser. The wavelength tuning range was 43 nm at this repetition rate and extended over 52nm (1518–1570nm) at 20GHz. Minimisation of the overall ring dispersion offered wavelength tunability at nearly constant repetition rate throughout the whole tuning range.
110 citations
TL;DR: In this paper, photo-induced Bragg reflectors at 1480 nm are written at both ends of the fiber amplifier and laser oscillation clamps the gain and suppresses low frequency signal or pump induced gain fluctuations.
Abstract: Two photoinduced Bragg reflectors at 1480 nm are written at both ends of the fibre amplifier. Above threshold, laser oscillation clamps the gain and suppresses low frequency signal or pump induced gain fluctuations.
91 citations
TL;DR: In this paper, a method to suppress noise in a high harmonic mode-locked erbium fiber laser is proposed and realised for the first time, dithering the cavity length at a kilohertz rate.
Abstract: A novel method to suppress noise in a high harmonic mode-locked erbium fibre laser is proposed and realised for the first time, dithering the cavity length at a kilohertz rate. This method makes only one supermode in the laser dominant and suppresses the others. A fibre laser so stabilised has enabled 2.5 Gbit/s soliton transmission over 205 km fibre remaining error free for 100 min, and in a recirculating loop achieving a 10/sup -9/ bit error rate at 12000 km, respectively. >
TL;DR: In this paper, an Er-doped waveguide amplifier fabricated by plasma enhanced chemical vapour deposition is described, achieving a maximum net gain of 5 dB and a gain coefficient of 0.67 dB/cm.
Abstract: An Er-doped waveguide amplifier fabricated by plasma enhanced chemical vapour deposition is described. A maximum net gain of 5 dB and a gain coefficient of 0.67 dB/cm are obtained in a 0.48 wt% Er-doped waveguide pumped at 420 mW at a wavelength of 0.98 μm. The 0 dB gain threshold is 23 mW.
TL;DR: Stable and efficient self-mode locking in a Q-switched highly doped erbium fiber laser has been demonstrated and the proposed mechanism of the pulse formation based on self-phase modulation agrees well with the observed pulse characteristics.
Abstract: Stable and efficient self-mode locking in a Q-switched highly doped erbium fiber laser has been demonstrated The proposed mechanism of the pulse formation based on self-phase modulation agrees well with the observed pulse characteristics
TL;DR: 250-fs pulses have been generated directly from a passively mode-locked ytterbium–erbium figure-of-eight laser, made to produce regular pulse bursts at the round-trip frequency, with repetition rates in excess of 300 GHz.
Abstract: 250-fs pulses have been generated directly from a passively mode-locked ytterbium–erbium figure-of-eight laser. In addition to the usual characteristic of one pulse per round trip, the laser could be made to produce regular pulse bursts at the round-trip frequency, with repetition rates in excess of 300 GHz.
TL;DR: Using first-principles calculations, the nature of erbium point defects in crystalline silicon is investigated and the total energy of an erbiam point defect at several high-symmetry sites and with two different oxidation states is computed.
Abstract: The possible technological importance of rare-earth-doped semiconductors has led to great interest in these materials. However, little at the atomic level is hitherto known about such defects in the host lattice. Using first-principles calculations, the nature of erbium point defects in crystalline silicon is investigated. The total energy of an erbium point defect at several high-symmetry sites and with two different oxidation states is computed. Among the configurations studied, the minimum-energy one is ${\mathrm{Er}}^{3+}$ at a tetrahedral interstitial site. The nature of the Er-related defect levels is determined.
TL;DR: Using a polarisation-maintaining erbium-doped fiber near the zero dispersion wavelength and a bulk InGaAsP saturable absorber, the authors in this article passively model a fiber laser to generate nearly transform-limited 320 fs pulses with 40pJ energy.
Abstract: Using a polarisation-maintaining erbium-doped fibre near the zero dispersion wavelength and a bulk InGaAsP saturable absorber, the authors passively modelock a fibre laser to generate nearly transform-limited 320 fs pulses with 40pJ energy. The laser produces a stable state of linear polarisation and the semiconductor, which acts both as a slow and fast saturable absorber, self-starts the laser.
TL;DR: In this paper, a low GVD polarisation sensitive isolator and reducing the fiber length in a nonlinear loop was used to obtain 124 fs pulses at 1-57 μm.
Abstract: Optical pulses as short as 98 fs at 1-57 μm have been successivelly generated for the first time directly from a laser-diode pumped erbium-doped fibre laser with a nonlinear amplifying loop mirror. By using a low GVD polarisation sensitive isolator and reducing the fibre length in a nonlinear loop, 124 fs pulses were obtained. They were further shortened to 98 fs by installing an EDFA as an active pulse compressor and a positive GVD fibre for chirp compensation
TL;DR: In this paper, a 0.98 μm laser-diode-pumped waveguide amplifier was successfully realized by using an Er-doped silica-based planar lightwave circuit.
Abstract: A 0.98 μm laser-diode-pumped waveguide amplifier is successfully realised by using an Er-doped silica-based planar lightwave circuit. The highest signal gain of 9.4 dB is achieved at a signal wavelength of 1.533 μm with a pump power of 99 mW, using a highly efficient erbium-doped waveguide and high power laser diodes.
TL;DR: In this article, a mathematical model of the strong, resonantly enhanced nonlinear phase shift recently reported in Er-doped fibers which relates the phase shift and signal loss to the fiber parameters and the pump and signal wavelengths, is presented.
Abstract: A mathematical model of the strong, resonantly enhanced nonlinear phase shift recently reported in Er-doped fibers which relates the phase shift and signal loss to the fiber parameters and the pump and signal wavelengths, is presented. Predictions are in fair agreement with the phase shift and loss measured in an experimental Er-doped fiber switch based on this effect. A strong, nearly wavelength independent contribution to the nonlinear phase shift is observed in the switch. The model suggests that this effect is due to the same nonlinear effect arising from one or more vacuum ultraviolet (VUV) transitions in Er/sup 3+/. >
TL;DR: In this paper, 100 fs pulses are generated in passively mode-locked erbium fiber with small negative group-velocity dispersion at a pump power significantly higher than the mode-locking threshold.
Abstract: 100 fs pulses are generated in passively mode‐locked erbium fiber lasers with small negative group‐velocity dispersion. The pulses are obtained at a pump power significantly higher than the mode‐locking threshold. An optimization of fiber lengths leads to the elimination of pedestal formation and the generation of stable pulse trains with high contrast ratios.
TL;DR: The incorporation of erbium from a solid source into molecular beam epitaxy (MBE) Si and Si/Ge alloys grown at substrate temperatures of 500 degrees C and 700 degrees C has been studied by photoluminescence, electrical measurements, secondary-ion mass spectrometry (SIMS), Rutherford backscattering (RBS) and transmission electron microscopy (TEM) as mentioned in this paper.
Abstract: The incorporation of erbium from a solid source into molecular beam epitaxy (MBE) Si and Si/Ge alloys grown at substrate temperatures of 500 degrees C and 700 degrees C has been studied by photoluminescence, electrical measurements, secondary-ion mass spectrometry (SIMS), Rutherford backscattering (RBS) and transmission electron microscopy (TEM). Erbium concentrations between 1018 and 1022 cm-3 were obtained but the maximum photoluminescence intensity was from samples with an erbium concentration of 2*1018 cm-3. Above this concentration the onset of erbium precipitation could just be observed by TEM. The authors found no shallow donors or acceptors attributable to erbium but they observed a high concentration of deep acceptors with an activation energy of 360 meV; these may be due to impurities in the erbium source rather than being directly related to the rare earth. Implantation with oxygen is found to enhance the Er3+-related photoluminescence signal when measured at temperatures greater than 77 K but to have little effect on the low-temperature luminescence. A detailed study of the temperature dependence of the luminescence reveals tree quenching mechanisms with average activation energies of approximately 5, 20 and 130 meV. The authors attribute the first two to de-excitation effects in the matrix, and the last to processes competing with the internal 4f transition.
TL;DR: Passive Q switching of an Er:phosphate glass laser using Er:Ca5(PO4)3F (Er:FAP) as a saturable absorber intracavity (IC) load is described in this article.
Abstract: Passive Q switching of an Er:phosphate glass laser using Er:Ca5(PO4)3F (Er:FAP) as a saturable absorber intracavity (IC) load is described for the first time. Q‐switched output was obtained consisting of a 6‐mJ single pulse of 83 ns full width at half maximum, with a 20% efficiency relative to the corresponding free‐running output in the absence of the IC Er:FAP load.
TL;DR: In this article, four independently modulated 10 GHz erbium fiber ring laser channels were transmitted over 205 km with a penalty of less than 1.5 dB, and the experiment was performed entirely with commercial components and semiconductor laser diodes.
Abstract: Four independently modulated 10 Gbit/s channels were transmitted over 205 km with a penalty of less than 1.5 dB. The pulse source comprised a stabilised 10 GHz erbium fibre ring laser, multiplexed to 40 Gbit/s in a single polarisation by four independent lithium niobate modulators. Following transmission the requirement to kick start the demodulator is avoided using a 40 GHz electronic clock recovery circuit with a 10 GHz output. The experiment is performed entirely with commercial components and semiconductor laser diodes.
TL;DR: A green, Er3+ doped fluorozirconate fiber laser, pumped with a commercial 801 nm laser diode, was presented in this article, achieving a green output power of 1mW for 20mW of launched pump power and 3mw for 40mw of pump power.
Abstract: A green, Er3+ doped fluorozirconate fibre laser, pumped with a commercial 801 nm laser diode is presented. Green output powers of 1mW for 20mW of launched pump power and 3mW for 40mW of pump have been achieved.
TL;DR: In this article, a comprehensive model of erbium-doped integrated optical waveguide amplifiers that include high concentration dissipative ion-ion interactions is presented, based on actual waveguide parameters.
Abstract: A comprehensive model is presented of erbium-doped integrated optical waveguide amplifiers that include high concentration dissipative ion-ion interactions. Calculations based on actual waveguide parameters closely reproduce measured gains for different pump powers and different erbium concentrations up to 60*10/sup 24/m/sup -3/. The quenching concentration for erbium-doped phosphate glass is found to be 20-30*10/sup 24/m/sup -3/.
TL;DR: In this article, the effects of potential loss mechanisms on the performance of erbium-doped resonant fiber lasers and superfluorescent fiber sources were explored via computer simulations, and the rate equations for paired ions were used to understand their saturation behavior and their effect on the slope and threshold of fiber sources.
Abstract: To explain the sub-optimal performance of erbium-doped resonant fiber lasers and superfluorescent fiber sources observed experimentally, the effects of potential loss mechanisms are explored via computer simulations. Pump excited-state absorption (ESA) at 980 nm and 1.48 micrometers , and signal ESA are unable to explain the dependence of the observed effects on concentration. Cooperative upconversion among uniformly distributed erbium ions fails to explain the observed reduction in source slope efficiency with increasing concentration. On the other hand, rapid cross-relaxation between paired ions, which might form in high concentration fibers, can produce the observed dependences. Rate equations for paired ions are used to understand their saturation behavior and their effect on the slope and threshold of fiber sources. Methods to assess the fraction of paired ions are discussed. Measurements suggest that about 18% of the ions in an aluminum co-doped silica fiber with 5 X 10 19 Er 3+ /cm 3 are paired. The effects of paired ions on the gain of Er-doped fiber amplifiers are also briefly discussed.
TL;DR: In this paper, a femtosecond erbium-doped fiber laser with nonlinear polarisation rotation is presented, in which a polariser is installed at a point-symmetric position against a polarisation-sensitive optical isolator in the ring laser cavity.
Abstract: A new type of femtosecond erbium-doped fibre laser with nonlinear polarisation rotation is presented, in which a polariser is installed at a point-symmetric position against a polarisation-sensitive optical isolator in the ring laser cavity This technique enables us to remove the continuum (DC component) in the oscillation waveform completely and to obtain a stable pulse train as short as 136–145 fs with a 56 MHz repetition rate
TL;DR: Combining a gain-switched semiconductor laser, an erbium-doped fiber amplifier, and two cascaded fibers for compression, optical pulse trains of 0.63 ps FWHM in autocorrelation trace, with certain suppression of wing structures, were successfully generated as discussed by the authors.
Abstract: Combining a gain-switched semiconductor laser, an erbium-doped fiber amplifier, and two cascaded fibers for compression, optical pulse trains of 0.63 ps FWHM in autocorrelation trace, with certain suppression of wing structures, were successfully generated. Evaluated energy in each pulse was >or=17 pJ. A computer simulation of the soliton-effect compression of gain-switched pulses containing substantial chirps was performed. Optimization of the pulse train by simply controlling the DC bias current on the master distributed-feedback (DFB) laser was clarified. >
TL;DR: Using a semiconductor saturable absorber, an erbium-doped fiber laser has been passively mode locked to yield pulses of 840 fs with pulse energies of 0.85 nJ.
Abstract: Using a semiconductor saturable absorber, an erbium‐doped fiber laser has been passively mode locked to yield pulses of 840 fs with pulse energies of 0.85 nJ. Stable mode locking at the fundamental roundtrip frequency and also at the second and third harmonic has been achieved.
Patent•
19 Nov 1993
TL;DR: In this article, an optical amplifier with an erbium doped core surrounded by cladding, a pump for pumping the fiber with pump light at a pump wavelength coupled to the fiber, input means for inputting a signal to be amplified to the amplifier and output means for outputting an amplified signal from the amplifier.
Abstract: An optical amplifier which includes an optical fiber having an erbium doped core surrounded by cladding, a pump for pumping the fiber with pump light at a pump wavelength coupled to the fiber, input means for inputting a signal to be amplified to the amplifier and output means for outputting an amplified signal from the amplifier. The fiber has a NA higher than 0.2. The difference in the coefficient of thermal expansion of the core adjacent the core/cladding interface and the coefficient of thermal expansion of the cladding at at least one radius less than 2 μm from said interface is lower than a predetermined value, corresponding to a ratio of erbium loss to background loss, at said pump wavelength, and greater than a minimum ratio of about 20 when erbium loss is 0.15 dB/m and about 120 when erbium loss is 3.5 dB/m.