Showing papers on "Fiber laser published in 1986"
TL;DR: The frequency-doubled light generated in the glass fibers was sufficient to pump a commercial Rh6G dye laser with ~19% efficiency at 570 nm.
Abstract: Efficient frequency doubling of a cw Q-switched and mode-locked Nd:YAG laser has been observed in commercial single-mode optical glass fibers. Pulses of duration ~55 psec and intensities as high as ~0.55 kW were produced at 0.53 μm. The maximum peak power-conversion efficiency measured was ~3%. The frequency-doubled light generated in the glass fibers was sufficient to pump a commercial Rh6G dye laser with ~19% efficiency at 570 nm.
560 citations
TL;DR: In this article, the small-signal modulation characteristics of a number of different laser structures are compared with emphasis on the laser response to 8 Gbit/s modulation, and the considerations used to achieve a record 26.5 GHz bandwidth in a 1.3 μm InGaAsP laser at -60°C are described.
Abstract: Recently, the bandwidths of semiconductor lasers, detectors, and optical transmission systems have been dramatically increased. The considerations used to achieve a record 26.5 GHz bandwidth in a 1.3 μm InGaAsP laser at -60°C are described here. The small-signal modulation characteristics of a number of different laser structures are compared. Several large-signal modulation experiments are described with emphasis on the laser response to 8 Gbit/s modulation.
200 citations
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01 Jan 1986
TL;DR: In this paper, the authors describe the characteristics of X-ray and free-electron laser systems, including beam characteristics, beam characteristics and efficiency, operating requirments, reliability and maintenance, safety considerations, applications and commercial availability.
Abstract: Basic physics and optics, internal workings, beam characteristics and efficiency, operating requirments, reliability and maintenance, safety considerations, applications and commercial availability, X-ray lasers, free-electron lasers, advanced semiconductor lasers and fiber lasers.
158 citations
TL;DR: In this paper, low-loss fibers containing rare-earths have been produced with high absorption levels in the visible and near infrared regions, which makes the fibers attractive for use in long distributed sensors, as well as low-threshold fiber lasers.
Abstract: Low-loss fibers containing rare-earths have been produced with high absorption levels in the visible and near infrared regions. Although containing relatively large quantities of rare-earth impurity dopants, the fibers possess low-loss windows where the attenuation is similar to that observed in undoped fibers. This attribute makes the fibers attractive for use in long distributed sensors, as well as low-threshold fiber lasers. Fiber characteristics relevant to these two applications are uniformity of dopant incorporation, absorption and fluorescence spectra, and fluorescence lifetime. These measurements are presented, together with their respective temperature dependences. The fiber fabrication method is described and results given for Nd3+-, Er3+-, and Tb3+-doped fibers.
154 citations
TL;DR: Tunable CW lasing was achieved for the first time in an Er3+-doped fiber laser, which has an overall tuning range of 25 nm in the region of \lambda = 1.54 /mu m as mentioned in this paper.
Abstract: Tunable laser action has been obtained in Nd3+- and Er3+-doped single-mode fiber lasers. In the case of the Nd3+-doped fiber, an extensive tuning range of 80 nm has been achieved. Tunable CW lasing also has been observed for the first time in an Er3+-doped fiber laser, which has an overall tuning range of 25 nm in the region of \lambda = 1.54 /mu m.
139 citations
TL;DR: In this paper, a theoretical analysis of superfluorescence in short active fiber devices for fiber system applications requiring broad-band light sources was performed using a mode overlap approach, and simple expressions for the threshold and energy conversion efficiency of this new class of devices were derived.
Abstract: We report a theoretical analysis of superfluorescence in short active fiber devices for fiber system applications requiring broad-band light sources. Using a mode overlap approach, we derive simple expressions for the threshold and energy conversion efficiency of this new class of devices, and study the effect of the fiber V -number and internal loss on their overall performance. We show that near single-mode Nd:YAG single crystal fibers pumped near 810 nm, possibly with a high-power laser diode, are anticipated to exhibit thresholds on the order of a few milliwatts, conversion efficiencies in excess 35 percent, and power-independent bandwidths of several nanometers.
67 citations
TL;DR: A tunable Nd(3+)-doped monomode-fiber laser has been constructed that operates continuously at room temperature and output powers were achieved for the two ranges from pumping by a dye laser operating at 590 nm.
Abstract: A tunable Nd(3+)-doped monomode-fiber laser has been constructed that operates continuously at room temperature. The tuning range covered is 0.900-0.945 and 1.070-1.135 microm. Output powers of 3 mW for 53 mW of absorbed pump and 2 mW for 35 mW of absorbed pump, respectively, were achieved for the two ranges from pumping by a dye laser operating at 590 nm.
62 citations
TL;DR: In this paper, an intracavity acousto-optic modulator was used to switch pulses of 200 ns duration and 8.8 W peak power at a repetition rate of 100 Hz.
Abstract: Q-switched operation of a neodymium-doped monomode fibre laser at 1.08 μm has been demonstrated. An intracavity acousto-optic modulator was used to switch pulses of 200 ns duration and 8.8 W peak power at a repetition rate of 100 Hz.
57 citations
TL;DR: Several low crosstalk 4 × 4 crossbar optical switch arrays have been fabricated for use at λ = 1.3 \mu m as mentioned in this paper, each array consists of 16 independently functioning directional coupler switches and the average insertion loss is 5.2 dB.
Abstract: Several low crosstalk 4 × 4 crossbar optical switch arrays have been fabricated for use at \lambda = 1.3 \mu m. Each array consists of 16 independently functioning directional coupler switches. We describe the typical device performance characteristics. The average insertion loss is 5.2 dB. Crosstalk levels routinely measured < -35 dB. The voltage required to operate the device is ≈ 13 V. The inputs to one of the device arrays were permanently attached to four laser transmitters using lensed polarization maintaining fiber at the laser end and an array of polarization maintaining fibers at the device end.
56 citations
Patent•
27 May 1986
TL;DR: In this article, the authors describe a catheter consisting of a single optical fiber or a plurality of optical fibers arranged to give overlapping output patterns for large area coverage, where the output energy is applied to a silica-based optical fiber.
Abstract: Laser energy produced by a laser operating in the mid-infrared region (approximately 2 micrometers) is delivered by an optical fiber in a catheter to a surgical site for biological tissue removal and repair. Disclosed laser sources which have an output wavelength in this region include: Holmium-doped Yttrium Aluminum Garnet (Ho:YAG) ,Holmium-doped Yttrium Lithium Fluoride (Ho:YLF) , Erbium-doped YAG, Erbium-doped YLF and Thulium-doped YAG. For tissue removal, the lasers are operated with relatively long pulses at energy levels of approximately 1 joule per pulse. For tissue repair, the lasers are operated in a continuous wave mode at low power. Laser output energy is applied to a silica-based optical fiber which has been specially purified to reduce the hydroxyl-ion concentration to a low level. The catheter may be comprised of a single optical fiber or a plurality of optical fibers arranged to give overlapping output patterns for large area coverage.
53 citations
TL;DR: Simple conical microlenses are fabricated on the end of a vapor-axial-deposition single-mode fiber to increase the coupling efficiency between the laser diode and the single- mode fiber.
Abstract: Simple conical microlenses are fabricated on the end of a vapor-axial-deposition single-mode fiber to increase the coupling efficiency between the laser diode and the single-mode fiber. The lowest coupling loss, 3 dB, has been achieved by using a 1.3-μm InGaAsP buried-heterostructure laser diode and a single-mode fiber. Experimental results on coupling efficiency and the loss penalty due to lateral misalignment are also reported. This conical lens is easy to manufacture and reproduce.
TL;DR: In this article, the development of CW 1.06-and 1.32-μm fiber lasers made of short sections of Nd:YAG single crystal fibers optically end-pumped either with an Argon-ion laser (α = 0.5145\mu m) or a single laser diode (α ≤ 0.817 µm).
Abstract: We report the development of CW 1.06- and 1.32-μm fiber lasers made of short sections of Nd:YAG single crystal fibers optically end-pumped either with an Argon-ion laser ( \lambda = 0.5145\mu m) or a single laser diode ( \lambda = 0.817\mu m). High conversion efficiencies, a few milliwatt thresholds and 10-20 mW output powers are reported, as well as a good coupling efficiency to a standard single-mode fiber. Loss mechanisms and means of reduction are also investigated for a variety of fiber lasers in either guided or unguided configurations.
05 Aug 1986
TL;DR: A low threshold for ablation and clean cuts with no charring compare favorably with excimer laser studies of tissue ablation.
Abstract: A solid state Er:YAG laser operating at 2.94μm, which is at the absorption peak of biological tissue, was used to ablate calcified and uncalcified atherosclerotic plaque in human arteries. The experiments were done in vitro. The laser radiation was passed through a flexible zirconium fluoride glass fiber, with virtually no loss, onto human aortas in saline solution. A low threshold for ablation and clean cuts with no charring compare favorably with excimer laser studies of tissue ablation.
TL;DR: In this article, a neodymium-doped monomode fiber laser operating at 1.08 µm has been actively mode-locked using intracavity acousto-optic loss modulation.
Abstract: A neodymium-doped monomode fibre laser operating at 1.08 µm has been actively mode-locked using intracavity acousto-optic loss modulation. The mode-locked laser output consisted of a train of pulses of less than 1 ns FWHM with an energy of ~17 pJ at a repetition rate of 41.45 MHz. When the laser was simultaneously Q-switched the peak power of the mode-locked pulses inside the 690 ns-wide envelope was enhanced by more than three orders of magnitude.
TL;DR: In this paper, an Nd3+doped silica single-mode fiber laser with a GaAlAs laser diode was reported to achieve a CW output power in excess of 1 mW at 1.088 µm with a slope efficiency of 33%.
Abstract: We report the efficient operation an Nd3+-doped silica single-mode fibre laser pumped by a GaAlAs laser diode. A CW output power in excess of 1 mW at 1.088 µm has been obtained with a slope efficiency of 33%. Q-switched operation of this device is also reported.
TL;DR: In this paper, a monomode silica fiber doped with Nd has been used for the first demonstration of cw laser action on the 4F3/2 to 4I9/2 transition of Nd in a glass host.
24 Feb 1986
TL;DR: By virtue of their broad fluorescence linewidth, rare-earth-doped singlemode fiber lasers could allow the construction of tunable sources and broadband optical amplifiers for wavelength division multiplexing long-distance optical communications systems as mentioned in this paper.
Abstract: By virtue of their broad fluorescence linewidth, rare-earth-doped single-mode fiber lasers could allow the construction of tunable sources and broadband optical amplifiers for wavelength division multiplexing long-distance optical communications systems. Similarly, doped-fiber amplifiers could also provide a means of overcoming soliton propagation losses.
TL;DR: In this article, the fabrication and operation of an Nd3+-doped silica single-mode fiber laser using a distributed fiber grating as the feedback element is reported, with a threshold of less than 2mW, a slope efficiency of 19% and an output bandwidth at the lasing wavelength of 1.084µm of 16GHz, significantly narrower than the conventional cavity design.
Abstract: The fabrication and operation of an Nd3+-doped silica single-mode fibre laser using a distributed fibre grating as the feedback element is reported. The laser had a threshold of less than 2mW, a slope efficiency of 19% and an output bandwidth at the lasing wavelength of 1.084µm of 16GHz, significantly narrower than the conventional cavity design.
TL;DR: In this paper, the first semiconductor-optical fiber ring laser is presented, which uses an InGaAsP traveling wave optical amplifier as the gain medium and a 1m length of highly birefringent fiber as the feedback loop.
Abstract: We demonstrate the first semiconductor‐optical fiber ring laser. The laser uses an InGaAsP traveling wave optical amplifier as the gain medium and a 1‐m length of highly birefringent fiber as the feedback loop. Output coupling is provided by a fiber directional coupler. The highly birefringent fiber is used as an intracavity wavelength filter, enabling single‐frequency oscillation with a narrow linewidth at a wavelength near 1.55 μm.
TL;DR: In this article, the authors present a theory of the soliton laser which examines how an external optical fiber enables a laser to produce shorter pulses than it could produce alone, and show how the lower limit to the mode-locked pulse width can arise.
Abstract: We present a theory of the soliton laser which examines how an external optical fiber enables a laser to produce shorter pulses than it could produce alone. We begin by discussing a phenomenological laser model which shows how the lower limit to the mode-locked pulse width can arise. This model is coupled to an external optical fiber cavity, into which a part of the output beam is launched. The returning pulse from the fiber cavity is then mixed with a circulating pulse in the laser at the output mirror. We have found stable solutions which are nearly periodic in the external cavity. We also find more than one solution for a given set of model parameters, depending on the initial conditions. The radiation (non-soliton) part of the propagation in the optical fiber cannot be ignored. It acts as a buffer between the tendency of the fiber to produce solitons, and the fact that a pure soliton is not an exact fixed point of the laser model.
TL;DR: In this paper, the effects of Rayleigh backscatter feedback from single-mode fibers on the spectral behavior of 1.5μm InGaAsP DFB lasers were measured.
Abstract: The effects of Rayleigh backscatter feedback from single-mode fibers on the spectral behavior of 1.5μm InGaAsP DFB lasers were measured. Rayleigh backscattering narrows the laser linewidth and induces frequency hops. The probability distribution for finding the laser at a particular frequency is reasonably approximated by a Gaussian distribution which has a width proportional to the laser-fiber coupling efficiency. Laser frequency excursions up to 1 GHz were observed and larger shifts are predicted to occur for stronger laser-fiber coupling. The experimental results agree well With a theory based on the Van der Pol oscillator model.
TL;DR: In this paper, single and multi-mode pumped stimulated Brillouin scattering fiber laser was experimentally investigated and it was found that both are spontaneously mode-locked and can be obtained with pulses as short as 4 ns.
03 Jan 1986
TL;DR: In this paper, a sensor system where a number of Fabry-Perot interferometer sensors are placed in series on a single-mode fiber is discussed, where each sensor is resonant within a unique bandpass of optical wavelengths and transmits with small attenuation at all other wavelengths.
Abstract: A sensor system where a number of Fabry-Perot interferometer sensors are placed in series on a single-mode fiber is discussed. Each Fabry-Perot sensor is resonant within a unique bandpass of optical wavelengths and transmits with small attenuation at all other wavelengths. Fiber Fabry-Perot interferometers with narrow-band resonances are formed by placing a matched pair of bandpass reflectors on the fiber. The sensor system has three major subsystems: a swept frequency laser, frequency selective Fabry-Perot sensors, and demodulation hardware. A grating formed by holographic process is placed in the evanescent field to produce a frequency selective reflector. Individual sensors are polled by a frequency swept laser. As the laser wavelength is scanned over the resonance bandpass of the first sensor, Fabry-Perot fringes from the first sensor are read out. As the laser continues to sweep its optical frequency, the first sensor's gratings no longer act as reflectors; the sensor becomes transparent to the optical probe. After a sufficient optical wavelength guard band, the resonance band of the second sensor is reached and fringes from the second sensor are read out. Fabry-Perot phase and fringe order information are recovered by a combination of optical and electronic signal processing. The optical processor is a second Fabry-Perot interferometer which is used as an analyzer to aid recovery of the phase information.
03 Jan 1986
TL;DR: Optical frequency domain reflectometry (OFDR) shows promise as a diagnostic tool for high resolution ranging in fiber optic networks/integrated optic devices, and for high-resolution distributed fiber optic sensing as discussed by the authors.
Abstract: Optical frequency domain reflectometry (OFDR) shows promise as a diagnostic tool for high resolution ranging in fiber optic networks/integrated optic devices, and for high resolution distributed fiber optic sensing. Chirped semiconductor lasers may be employed to obtain submillimeter spatial resolutions. This paper discusses applications, some signal processing aspects of this technology, the potential, and actual performance of some experimental laboratory OFDR systems.
TL;DR: In this paper, a spatial coherence analysis of light propagation in optical fibers illuminated with a laser source is presented, where modulus and phase of the complex degree of spatial coherent across the end cross section are measured by means of Michelson-type wavefront-reversing interferometry.
Abstract: A spatial coherence analysis of light propagation in optical fibers illuminated with a laser source is presented. Modulus and phase of the complex degree of spatial coherence across the end cross section are measured by means of Michelson-type wave-front-reversing interferometry. Interference fringe patterns of a laser beam emerging from the output end of optical fibers are also photographed. Comparison of the measurement with theory enables us to characterize the modal content in a quasi-single-mode fiber.
24 Feb 1986
TL;DR: In this article, the authors proposed distributed feedback (DFB) and cleaved-coupled-cavity (C3) schemes for single-longitudinal mode control.
Abstract: Within the last decade, very significant advances have been made in semiconductor lasers. These advances were direct results of the various specific requirements demanded by optical fiber communications on semiconductor lasers as the light source. In the 1970s, research and development have been concentrated in laser stripe geometries for achieving stable transverse fundamentalmode operation required for efficient and stable coupling into then multimode optical fibers. In the early 1980s, with the advent of low-loss singlemode fiber at 1.57 μm, it became obvious that development of a single-frequency semiconductor laser operating at 1.57 μm would be very important in very high-data-rate long-distance transmission. This fueled the research and development of semiconductor laser schemes for single-longitudinalmode control. Two schemes of major interest are distributed feedback (DFB) and cleaved-coupled-cavity (C3 ). While the wavelength of a DFB laser is fixed at the time of manufacturing by the grating period, that of a C3 laser is electrically tunable. While the side-mode suppression, linewidth, and threshold of a DFB laser depend on the relative position of the end facet with respect to the grating period, those of a C3 laser depend on the gap separation between the two coupled cavities. While the DFB scheme is incorporateable only to certain stripe-geometry laser structures and is technologically feasible for lasers beyond certain lasing wavelengths (due to difficulties in fabricating very short grating periods), the C3 scheme is applicable to all laser structures and wavelengths. Thus the choice depends on the specific applications in mind. Although these lasers were called single-frequency sources, they fell very short of their given name for three major yet unresolved problems.
TL;DR: In this article, a 5μm band CO laser beam through As2S3 glass core Teflon fluorinated ethylene propylene clad fibers is described, where the maximum transmitted power is as high as 62 W with a 700μm core diameter fiber, corresponding to a power intensity of 16 kW/cm2 at the fiber output end.
Abstract: Optical power transmission of 5‐μm band CO laser beam through As2S3 glass core Teflon fluorinated ethylene propylene clad fibers is described. The maximum transmitted power is as high as 62 W with a 700‐μm core diameter fiber, which corresponds to a power intensity of 16 kW/cm2 at the fiber output end. The influence of fiber bending on the transmission characteristics is also reported.
14 Feb 1986
TL;DR: In this article, a comprehensive review of the lens options available to the designer, for coupling semi-conductor lasers to single mode fiber, is given, including microlenses formed directly on tapered fibers, and designs based on one, or more discrete lenses.
Abstract: A comprehensive review is given, of the lens options available to the designer, for coupling semi-conductor lasers to single mode fiber. Various arrangements are considered, including microlenses formed directly on tapered fibers, and designs based on one, or more discrete lenses. The optical and mechanical advantages of the different approaches are compared. The highest coupling efficiencies are shown to be obtained, when high index materials are used in the first lens. A new design, based on a Si lens, in a confocal arrangement, is presented. A coupling efficiency of 70% is reported. Different means of bonding the critical alignments, including cementing, soldering, and laser welding are discussed.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: Plano–convex gradient-index lens coupling a laser diode to single-mode fiber was designed and fabricated by the ion exchange technique and a low coupling loss was achieved.
Abstract: Plano–convex gradient-index lens coupling a laser diode to single-mode fiber was designed and fabricated by the ion exchange technique. A low coupling loss (2 dB) was achieved.