Showing papers on "Erbium published in 1992"
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: 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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169 citations
CNET1
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.
135 citations
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.
116 citations
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.
113 citations
01 Feb 1992
TL;DR: The feasibility of using semiconductor laser diodes to pump EDFAs insures that EDFA's are practical devices which will have great impact on optical communications as power boosters, optical repeaters and optical preamplifiers as discussed by the authors.
Abstract: Erbium-doped fiber amplifiers (EDFA’s) operate in the 1.5?m wavelength telecommunications window and have achieved high gain, high output power and near ideal noise performance. The feasibility of using semiconductor laser diodes to pump EDFA’s insures that EDFA’s are practical devices which will have great impact on optical communications as power boosters, optical repeaters and optical preamplifiers.
92 citations
TL;DR: The first fiber laser operating above 3 mu m at room temperature was reported in this paper, where the first Er/sup 3+/-doped ZBLAN fiber pumped at 655 nm showed CW laser operation around 3.5 mu m.
Abstract: The first fibre laser operating above 3 mu m at room temperature is reported. An Er/sup 3+/-doped ZBLAN fibre pumped at 655 nm shows CW laser operation around 3.5 mu m. >
91 citations
24 Jun 1992
TL;DR: In high concentration erbium doped fibers (above 0.1 to 0.2%), randomly distributed ion ions are close enough to quench the 4II3/2 level via cooperative upconversion followed mostly by a non radiative deexcitation or less often (≃10-3) by a 980 nm photon emission.
Abstract: In high concentration erbium doped fibers (above 0.1 to 0.2%), randomly distributed erbium ions are close enough to quench the 4II3/2 level via cooperative upconversion followed mostly by a non radiative deexcitation or less often (≃10-3) by a 980 nm photon emission (Ref. 1).
85 citations
TL;DR: It is shown that switching action takes place at a power of a fraction of 1 mW, which provides a practical means of fabricating an all-optical fiber switch.
Abstract: We report the theoretical and experimental investigation of switching in a nonlinear twin-core erbium-doped fiber coupler. It is shown that switching action takes place at a power of a fraction of 1 mW. Thus it provides a practical means of fabricating an all-optical fiber switch.
72 citations
Patent•
23 Jul 1992TL;DR: In this article, an optical fiber for amplifying or sourcing a light signal in a single transverse mode is presented. But, it requires only conventional and readily available diode-based pump sources, and the amplifier provides power and small signal gains comparable to the best observed.
Abstract: An optical fiber for amplifying or sourcing a light signal in a single transverse mode The fiber comprises a host glass doped with erbium (Er) and a sensitizer such as ytterbium (Yb) or iron (Fe) Preferably the host glass is doped silicic glass (eg, phosphate or borate doped) Electrical energy is provided to diode lasers that pump the Nd laser rod, which in turn pumps the fiber Such a configuration for pumping the fiber provides a high energy transfer from the diodes to the Nd laser rod, which in turn enables high pumping powers to be coupled into the single-mode co-doped fiber Based on the amplification characteristics of the co-doped fiber and the efficient coupling of power from the laser diodes, the amplifier provides power and small signal gains comparable to the best observed, while requiring only conventional and readily available diode-based pump sources
69 citations
TL;DR: Self-induced transparency (SIT) has been observed in an erbium-doped resonant fiber waveguide with stable 2, 4, and multiple soliton pulses that broke up were clearly observed.
Abstract: Self-induced transparency (SIT) has been observed in an erbium-doped resonant fiber waveguide The waveguide had an erbium ion concentration of 8900 ppm, and was cooled to 42 K The pulse source was a 153-\ensuremath{\mu}m mode-locked Er-doped glass laser with a pulse width of 500 ps Stable 2\ensuremath{\pi}, 4\ensuremath{\pi}, and multiple soliton pulses that broke up were clearly observed
TL;DR: In this paper, the upconversion laser action in Er:LiYF4 with excitation at 1.55 μm resulting in cw emission at 0.55μm to a temperature of 95 K was reported.
Abstract: We report trio upconversion laser action in Er:LiYF4 with excitation at 1.55 μm resulting in cw emission at 0.55 μm to a temperature of 95 K and contrast its performance with earlier green erbium upconversion lasers.
TL;DR: In this article, the erbium is incorporated primarily as near spherical micro-precipitates which possess a cubic (rocksalt) structure consistent with their chemical composition being ErAs.
TL;DR: Pulses as short as 765 fs have been generated from an erbium doped, unidirectional, fiber ring laser, mode locked using the effect of intensity dependent polarisation rotation as discussed by the authors.
Abstract: Pulses as short as 765 fs have been generated from an erbium doped, unidirectional, fibre ring laser, mode locked using the effect of intensity dependent polarisation rotation. The output from the laser exhibits all the characteristics of temporal and spectral instability expected from a periodically amplified soliton system when the amplification length is a significant fraction of the soliton period
Patent•
28 Sep 1992TL;DR: In this paper, the authors describe a nini-structure which is generated using a slab-doping technique, with the doped layers being substantially thinner than the undoped layers, and preferably as thin as one atomic plane.
Abstract: A semiconductor film is provided characterized by having high carrier mobility and carrier density. The semiconductor film is doped with the rare-earth element erbium so as to improve its temperature stability. The semiconductor film is thereby particularly suited for use as a magnetic field sensing device, such as a Hall effect sensor or magnetoresistor. The semiconductor film is formed from a narrow-gap Group III-V compound, preferably indium antimonide, which is n-doped with the erbium to provide an electron density sufficient to increase temperature stability. In particular, the semiconductor film is characterized by a nini-structure which is generated using a slab-doping technique. The slab-doping process encompasses the growing of alternating layers of doped and undoped layers of the Group III-V compound, with the doped layers being substantially thinner than the undoped layers, and preferably as thin as one atomic plane. The electron density establishes an average extrinsic electron density within the combined undoped and doped layers of the Group III-V compound. The density of erbium in the doped layers is preferably sufficient to yield an average extrinsic electron density of between about 1×1016 cm-3 and about 1×1018 cm-3, while also achieving a carrier mobility greater than about 30,000 cm-2 /V-s at room temperature.
01 Feb 1992
TL;DR: In this paper, excited state absorption spectra were measured for the 4I11/2? 4F7/2 transition at 980 nm in Er-doped fluoride and fluorophosphate glass, by varying the pump wavelength from a tunable Ti:sapphire laser and monitoring the relative strength of the green upconverted fluorescence.
Abstract: Excited state absorption (ESA) spectra were measured for the 4I11/2? 4F7/2 transition at 980 nm in Er-doped fluoride and fluorophosphate glass, by varying the pump wavelength from a tunable Ti:sapphire laser and monitoring the relative strength of the green upconverted fluorescence. The ESA cross section spectra are the same order of magnitude in strength as the 980 nm ground state absorption, but shifted to shorter wavelength by 4-6 nm. The 980 nm ESA may limit the efficiency of high power erbium-doped fiber amplifiers, and provides a possible pump mechanism for IR upconversion pumped fiber lasers operating in the visible.
TL;DR: In this article, the radiation-induced absorption in erbium-doped optical fibres (EDfs) has been found to be strongly dependent on the fibre core composition, and compositional variations which may increase their radiation hardness have been tentatively identified.
Abstract: The radiation-induced absorption in erbium-doped optical fibres (EDfs) has been found to be strongly dependent on the fibre core composition. Implictions for erbium-doped fibre amplifier (EDFs) performance have been modelled, and compositional variations which may increase their radiation hardness have been tentatively identified.
TL;DR: A diode-pumped, integrated erbium fiber ring laser has been mode-locked at frequencies up to 14 GHz using a high speed lithium niobate amplitude modulator.
Abstract: A diode-pumped, integrated erbium fibre ring laser has been mode-locked at frequencies up to 14 GHz using a high speed lithium niobate amplitude modulator. Pulses of 20–30 ps duration have been generated with mean output powers of 7.5 mW. In addition, the laser could be efficiently tuned over the 1.52–1.57μm wavelength region.
TL;DR: In this article, a novel type of filter based on D fiber with an overlay grating is proposed, and its fabrication and characterisation is described and its use in an erbium doped fiber amplifier to obtain a flatter gain spectrum is discussed.
Abstract: A novel type of filter based on D fibre with an overlay grating is proposed. The fabrication and characterisation of the device are described and its use in an erbium doped fibre amplifier to obtain a flatter gain spectrum is discussed.
24 Jun 1992
TL;DR: In this article, the authors reported the realization of Er-doped silica-based waveguide amplifiers with a 19.4 cm-long waveguide at a concentration of 0.55 wt% with a pump power of 100 mW at a wavelength of 980 nm.
Abstract: We report the realization of Er-doped silica-based waveguide amplifiers. The gain is maximized in a 19.4 cm-long waveguide at a concentration of 0.55 wt% with a pump power of 100 mW at a wavelength of 980 nm. The linear dependence of the gain on the waveguide length is observed. A net gain of 13.7 dB is achieved at a wavelength of 1.535 µm with the Er-doped planar waveguide.
TL;DR: In this paper, the gain degradation of erbium-doped fiber amplifiers (EDFAs) with high Erbium ion (Er/sup 3+/) concentration at 1.48- and 0.98- mu m pump wavelengths is modeled by introducing inhomogeneous cooperative upconversion (IhCU).
Abstract: The gain degradation of erbium-doped fiber amplifiers (EDFAs) with high erbium ion (Er/sup 3+/) concentration at 1.48- and 0.98- mu m pump wavelengths is modeled by introducing inhomogeneous cooperative up-conversion (IhCU). General formulas describing the gain degradation as a function of IhCU rate are obtained by solving rate equations for population probabilities in the relevant Er/sup 3+/ energy levels. The experimental results, such as low gain for high Er/sup 3+/ concentration, and higher saturated gain with counterpropagation than with copropagation pumping, which have not yet been explained theoretically, are qualitatively explained by this model. Good agreement between the measured and calculated gain is obtained. The gain degradation characteristics at 1.48- and 0.98- mu m pump wavelengths are analyzed with this model. The advantage of counterpropagation pumping is determined qualitatively. The noise figure degradation is also evaluated. >
TL;DR: In this paper, the relative merits of exciting Er/sup 3+/ amplifiers at three wavelengths for which high-power laser diodes are available at 800, 980, and 1480 nm were examined.
Abstract: The authors examine relative merits of exciting Er/sup 3+/ amplifiers at the three wavelengths for which high-power laser diodes are available at 800, 980, and 1480 nm Model calculations are confirmed by a detailed experimental comparison of the power requirements for pumping in the 800-nm band and at 980 nm To obtain comparable performance with respect to gain and noise figure, 7-8 dB more power is required when pumping in the 800-nm-band >
Patent•
AT&T1
TL;DR: In this article, a method for forming an active optical device, including the step of depositing an erbium-doped active core by sputtering, is presented. But the active core has an atomic ratio of at least about 0.01, an absolute erbiam concentration of at at least 1.4x10µµ atoms per cubic centimeter, and a radiative lifetime of the lasing level of approximately 7 milliseconds.
Abstract: An active optical device comprises a glass, waveguiding structure (20,30,40,50) disposed on a substantially planar principal surface of a substrate (10). The structure includes a silica-based, erbium-doped active core (40). The active core has an erbium-to-silicon atomic ratio of at least about 0.01, an absolute erbium concentration of at least about 1.4x10²⁰ 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, negative nonlinear absorption was observed in a 16 at. % Er:YAG crystal using a laser diode operating at 787 and 784 nm, which was the center of an absorption peak that is related to the excited state absorption from 4I13/2 to 2H11/2.
Abstract: Negative nonlinear absorption, which causes the transmission to decrease as the laser intensity increases, was observed in a 16 at. % Er:YAG crystal using a laser diode operating at 787 and 784 nm. This effect for 787 nm was strong because 787 nm was the center of an absorption peak that is related to the excited‐state absorption from 4I13/2 to 2H11/2. It is suggested that these phenomena take place because the absorption cross section from 4I13/2 to 2H11/2 is larger than that from 4I15/2 to 4I9/2 using a double‐absorption model.
TL;DR: A series of irradiation tests on erbium fibre amplifiers using fibres with different codopant levels showed the range of gain losses induced and permit some conclusions about the relative roles of the fibre constituents as discussed by the authors.
Abstract: A series of irradiation tests on erbium fibre amplifiers using fibres with different erbium and codopant levels show the range of gain losses induced and permit some conclusions about the relative roles of the fibre constituents.
TL;DR: In this article, the effect of unwanted optical loss varying over 15 dB is automatically offset with an erbium-doped fiber amplifier used in an optical feedback configuration, where the loss compensation is possible for signal wavelengths over a 13 nm range centered at about 1550 nm.
Abstract: The effect of unwanted optical loss varying over 15 dB is automatically offset with an erbium-doped fiber amplifier used in an optical feedback configuration. The loss compensation is possible for signal wavelengths over a 13 nm range centered at about 1550 nm. The system dynamic range for loss fluctuation frequencies is zero to several kilohertz. The proposed loss compensation scheme simultaneously provides an automatic gain control function that stabilizes the gain against slow changes in input signal power or pump power. >
TL;DR: From this it is shown that a relationship between the threshold power and other primary system parameters can be quantitatively specified.
Abstract: Starting from the rate equations describing the interaction between a three-level atom and a two-wavelength field appropriate to the erbium-doped fiber lasers pumped by 980-nm light, we establish an analytical and explicit expression for the threshold pump power of the laser. From this it is then shown that a relationship between the threshold power and other primary system parameters can be quantitatively specified.
TL;DR: In this article, it was shown that the desired depletion of lower laser levels can be achieved in the case of Er3+ and Ho3+ by co-doping with other rare earth elements.
Abstract: Continuous wave (CW) operation of erbium3+ (Er3+)-, holmium3+ (Ho3−)- or thulium3+ (Tm3+)-doped ZBLAN fibre lasers, emitting at 2.7, 2.9 and 2.3 μm, is based on the depletion of their lower laser level by excited state absorption (ESA) of the appropriate selected pump wavelengths. This additional absorption process limits the efficiency of these laser transitions. The problem can be solved by the proper co-doping of the laser active dopants with other rare earth elements. It is shown that the desired depletion of the lower laser levels can be achieved in the case of Er3+ and Ho3+ by co-doping with Pr3+ and Eu3+.
Journal Article•
TL;DR: The comparison of the two types of laser ablations showed larger fragments and fewer types of molecules present after excimer laser treatment than after Er:YAG photoablation.
Abstract: The photoablative products from human cadaver corneas treated with lasers were investigated using gas chromatography and mass spectroscopy. The photoablations were done separately with an excimer laser (193 nm) and with an erbium: yttrium aluminum garnet (Er:YAG) laser (2.94 microns). More than 20 different types of molecules with a molecular weight of 40-400 mass units could be identified, most of which were found to be alkanes. The comparison of the two types of laser ablations showed larger fragments and fewer types of molecules present after excimer laser treatment than after Er:YAG photoablation.