Showing papers on "Fiber laser published in 1977"
TL;DR: Subnanosecond pulses in the 1120-1550-nm region are generated by multiple-order stimulated Raman scattering in a small core single-mode silica fiber pumped by a Q-switched and mode-locked Nd:YAG laser.
Abstract: Subnanosecond pulses in the 1120-1550-nm region are generated by multiple-order stimulated Raman scattering in a small core single-mode silica fiber pumped by a Q-switched and mode-locked Nd:YAG laser at 1064 nm. These near ir pulses are injected into various km long test fibers, and relative time delay changes between different wavelengths are used to determine dispersion in a region where fiber material dispersion is small. Zero material dispersion has been observed in germanium and boron-doped single-mode and multimode est fibers.
194 citations
Patent•
08 Nov 1977TL;DR: In this paper, a laser-to-fiber coupler is constructed by an optical waveguide arranged between a semiconductor laser and a transmitting optical fiber through which an optical beam emanating from the laser is transmitted in order to reduce the amount of a reflection beam from the optical fiber, which is injected into the active layer of the laser.
Abstract: A laser-to-fiber coupler is constructed by an optical waveguide arranged between a semiconductor laser and a transmitting optical fiber through which an optical beam emanating from the laser is transmitted in order to reduce the amount of a reflection beam from the optical fiber, which is injected into the active layer of the semiconductor laser. The waveguide is made by an optical fiber of which at least one of core radius or numerical aperture (N.A.) is smaller than those of the transmitting optical fiber.
71 citations
Journal Article•
32 citations
TL;DR: Good reproducibility of the low loss splice was achieved by contacting the fibers tightly before fusing them together, and ninety percent of twenty-one splices had losses less than 0.12 dB with a minimum loss of 0.02 dB.
Abstract: Low loss splicing of silica fibers by means of a 5-W CO2 laser has been demonstrated. Step-index fibers with a core diameter of 56 μm and an outer diameter of 154 μm were fused together. The chopped laser beam, effectively 2.3 W and about 1.0 mm in beam-spot diameter, was moved across the fiber ends at a speed of 10 μm/sec. Ninety percent of twenty-one splices had losses less than 0.12 dB with a minimum loss of 0.02 dB. Good reproducibility of the low loss splice was achieved by contacting the fibers tightly before fusing them together.
27 citations
TL;DR: In this article, the authors used a combination of a low-loss single-mode fiber and a well designed AlGaAs laser to achieve a repeater spacing at 800 Mbits/s.
Abstract: It has been confirmed by a preliminary transmission experiment that a repeater spacing at 800 Mbits/s can be lengthened up to 7.3 km, by using a combination of a low-loss single-mode fiber and a well designed AlGaAs laser. The laser is modulated by a signal current superimposed on a dc bias current above the threshold. This modulation scheme avoids the spectrum broadening of the laser at the cost of extinction ratio degradation. A discrepancy of about 13 dB exists between the measured and the calculated error-rate performance curves. The major part of the discrepancy, 10 dB, is due to the extinction ratio degradation.
25 citations
TL;DR: In this article, the characteristics of both semiconductor lasers, made of GaAs and related compounds, emitting at 0.85 μm or 1.05 μm and high neodymium-content lasers are discussed.
Abstract: Both low attenuation silica optical fibers with peak transmission in the wavelength regions of 0.85 μm, and 1.05 μm, and improved lasers at both wavelengths are now available. In this review paper, the principal components for emission, modulation and detection are described. The characteristics of both semiconductor lasers, made of GaAs and related compounds, emitting at 0.85 μm or 1.05 μm and high neodymium-content lasers are discussed. For modulation, current modulation of GaAs lasers and external electro-optic modulation are considered. Concerning detection, the realisation of Si photodetectors suitable at 0.85 μm and the new photodetectors at 1.05 μm from Ga1−x
In
x
As are reviewed.
15 citations
TL;DR: In this article, the authors established a criterion for the maximum amount of power that can be launched into an optical fiber relative to a front-emitting diode of given active layer (junction) thickness.
Abstract: We establish a criterion for the maximum amount of power that can be launched into an optical fiber relative to a front-emitting diode of given active layer (junction) thickness. According to this criterion it should be possible to obtain 7.5 times the amount of power from a light-emitting diode (LED) of optimum design relative to a front-emitting LED whose active layer of equal intrinsic brightness is 2.5 μm thick. We also discuss the performance of edge-emitting diodes and find that the LED's of our examples are capable of providing approximately 50 percent of the power expected from the ultimate diode configuration.
15 citations
TL;DR: The frequency spectrum of a continuous wave fiber-optic Raman laser is measured and observed to consist of several discrete lines covering a 3-nm spectral range, and degradation of the fiber has been reduced in the later devices.
Abstract: The frequency spectrum of a continuous wave fiber-optic Raman laser is measured and observed to consist of several discrete lines covering a 3-nm spectral range. The output of the laser also contains damped transients which are attributed to strong pump-depletion effects in the fiber. Previously observed degradation of the fiber has been reduced in the later devices.
10 citations
Patent•
11 Aug 1977
TL;DR: In this paper, a CO2 laser of a low output (0, 1 - 5W) was used as a heat source to cut an optical fiber at right angles by using CO 2 laser.
Abstract: PURPOSE:To cut an optical fiber at right angles by using CO2 laser of a low output (0,1 - 5W) as a heat source.
8 citations
TL;DR: In this paper, the laser oscillation of a GaAs-AlGaAs DH-structure laser with a bent guide was reported, and it was concluded that this mode selectivity was due to the multicavity effect.
Abstract: The laser oscillation of GaAs-AlGaAs DH-structure laser with a bent guide was reported. The threshold current density J th was about 3-15 kA/cm2, and the longitudinal mode was single up to 1.7 times J th . From the simulation experiments, it was concluded that this mode selectivity was due to the multicavity effect.
7 citations
TL;DR: In this paper, a radiation-hardened fiber-optic signal transmission system has been built that has a bandwidth of over 400 MHz with linear response, and an amplitude-modulated CW laser diode is used in the transmitter.
Abstract: A radiation-hardened fiber-optic signal transmission system has been built that has a bandwidth of over 400 MHz with linear response. An amplitude-modulated CW laser diode is used in the transmitter. Automatic bias compensation is applied to the laser in lieu of the typical temperature control. The system has provision to remotely select (via a fiber-optic control link) the attenuation between the signal input and the transmitter. A self-contained system-calibration pulse is also remotely triggerable. The transmitter has a volume of about 75 in3, including the battery power supply. The rise time of the system is 1.2 ns and the dynamic range is 35 dB. The transmitter and fiber-optic portions of the system are hardened to withstand a photon irradiation of more than 5 × 105 rad(Si)/s from a Febetron 705.
Patent•
02 Sep 1977
TL;DR: In this paper, the optical fiber's element group compound eyes form was used to convert the incoherent light of secondary dimensional image's each part into the coherent light with excellent quality.
Abstract: PURPOSE:To convert the incoherent light of secondary dimensional image's each part into the coherent light with excellent quality, by means of arraying optical fiber's element group compound eyes form.
TL;DR: Efficient methods to eliminate the speckle effect and to generate multicolor laser light are described.
Abstract: Multiwavelength lasers are used to compensate for color distortion in transmission of light through plastic optical fibers. Efficient methods to eliminate the speckle effect and to generate multicolor laser light are described.
01 Sep 1977
TL;DR: In this article, a rotating mirror with sectors of varying reflectivity is used in a mixed-ion argon-krypton laser to synthesize multicolor laser light, which is obtained by means of time multiplexing of oscillations at various wavelengths.
Abstract: Efficient generation of synthesized multicolor laser light, which ordinarily is limited by the competition between lasing lines, is obtained by means of time multiplexing of oscillations at various wavelengths. Experimental results are described wherein a rotating mirror with sectors of varying reflectivity is used in a mixed-ion argon-krypton laser.
01 Jan 1977
TL;DR: In this paper, a reliability investigation of double heterostructure (Al,Ga) as injection lasers intended for fiber optical communications is reviewed and the extrapolations are shown to be consistent with an extrapolation energy of ∼ 0.7 eV.
Abstract: Reliability investigations of double heterostructure (Al,Ga)As injection lasers intended for fiber optical communications are reviewed. Accelerated aging is discussed and the extrapolations are shown to be consistent with an extrapolation energy of ∼0.7 eV. The importance of dark line defects, uniform degradation, and gradual mirror damage for long-lived lasers is assessed. The feasibility of room temperature mean-time-to-failure in excess of one million hours is demonstrated and remaining problems described.
TL;DR: In this article, it was shown that a laser beam retains its spatial coherence during passage through a single-mode fiber waveguide 150 m long, and two types of laser interferometer utilizing such a waveguide were described.
Abstract: Experimental evidence is given that a laser beam retains its spatial coherence during passage through a single-mode fiber waveguide 150 m long. A description is given of two types of laser interferometer utilizing such a waveguide.
22 Feb 1977
TL;DR: In this paper, the authors present reliability studies of the "standard" CW AlGaAs lasers emitting at ~ 0.85 μm and advances in the technology of devices emitting in the 1 μm spectral region.
Abstract: Major areas of current research and development of laser diodes for fiber communications includes reliability studies of the "standard" CW AlGaAs lasers emitting at ~ 0.85 μm and advances in the technology of devices emitting in the 1 μm spectral region. Other areas of continuing research involve the control of lateral modes and the elimination of nonlinearities (kinks) in the power emission vs. current curves.
Patent•
02 Sep 1977
TL;DR: In this article, the authors proposed to realize the solution of problems such as binarization, miniturization, by controlling the laser output by radiating pumping laser light on fiber laser plate which makes numerous edge plane excitation fiber lasers into a bundle.
Abstract: PURPOSE:To realize the solution of problems such as binarization, miniturization, by controlling the laser output by means of radiating pumping laser light on fiber laser plate which makes numerous edge plane excitation fiber lasers into a bundle.