1
David J DiGiovanni, Clinton R Giles: Multi-stage optical fiber amplifier. AT&T Bell Laboratories, Eli Weiss, September 24, 1991: US05050949 (122 worldwide citation)

In this invention there is disclosed a multi-stage optical fiber amplifier for providing a new functon, that of gain equalization. The disclosed multi-stage optical fiber amplifier comprises at least two stages of amplification where each stage comprises an amplifying fiber having a different gain s ...


2
David J DiGiovanni, Victor Mizrahi, John L Zyskind: Article comprising an optical fiber laser. AT&T Bell Laboratories, M I Finston, August 17, 1993: US05237576 (83 worldwide citation)

An article, such as an optical communication system, which includes a laser formed in an optical waveguide or optical fiber having a rare-earth-doped core or core portion. In one embodiment, the optical resonant cavity of the laser is at least partially defined by a distributed Bragg reflector forme ...


3
David J DiGiovanni, Clinton R Giles: Multi-stage optical amplifier. AT&T Bell Laboratories, Eli Weiss, May 19, 1992: US05115338 (77 worldwide citation)

This invention relates to an Erbium-doped fiber amplifier having multiple stages of amplification for providing enhanced performance. More specifically, optical means is located intermediate first and second stages of doped optical amplifying fibers adapted to receive a pump signal at a pump wavelen ...


4
David J DiGiovanni, Joseph D Evankow, Jonathan A Nagel, Richard G Smart, James W Sulhoff, John L Zyskind: High power, high gain, low noise, two-stage optical amplifier. AT&T, Mark K Young, July 4, 1995: US05430572 (76 worldwide citation)

High output power, high gain, and low noise are achieved in a two-stage optical amplifier, suitable for use as a repeater for a long haul lightwave communication system, in accordance with the principles of the invention, by employing a first amplifying stage having a signal gain sufficiently small ...


5
David J DiGiovanni, Clinton R Giles, Stuart A Kramer, Gerald Nykolak, Herman M Presby, Jay R Simpson: High gain multi-mode optical amplifier. AT&T Bell Laboratories, Charles E Graves, February 16, 1993: US05187759 (55 worldwide citation)

Indiscriminately exciting the modes of a multi-mode optical fiber amplifier is avoided by an optical fiber amplifier design in which the excitation of pump modes in the core of a multi-mode fiber is controlled by controlling the pump light launching. The pump light is directed substantially along th ...


6
David J DiGiovanni, Kenneth L Walker: System comprising Er-doped optical fiber. AT&T Bell Laboratories, E E Pacher, October 22, 1991: US05058976 (39 worldwide citation)

The inventive optical fiber communication system comprises Si-based amplifier fiber whose core comprises Ge, Al, and Er. The amplifier fiber has an effective index difference (.DELTA.n) greater than 0.03, an effective core diameter a less than 3.5 .mu.m, a maximum Al concentration in the core of at ...


7
David J DiGiovanni, Jonathan A Nagel, Richard G Smart, James W Sulhoff, John L Zyskind: Method of mitigating gain peaking using a chain of fiber amplifiers. AT&T, April 11, 1995: US05406404 (35 worldwide citation)

The present invention relates to a method of mitigating gain peaking in a chain of fiber amplifiers by pumping the amplifiers at a predetermined wavelength to produce gain over a specified wavelength range.


8
David J DiGiovanni, Siddharth Ramachandran: Large mode area fibers using higher order modes. Furakawa Electric North America, January 30, 2007: US07171074 (34 worldwide citation)

The specification describes an optical fiber device wherein a LOM is converted to an HOM prior to entering the gain section. The gain section is a few mode fiber that supports the HOM. The output from the gain section, i.e. the HOM, may be utilized as is, or converted back to the LOM. With suitable ...


9
David J DiGiovanni, Kenneth L Walker: Single mode optical transmission fiber, and method of making the fiber. Lucent Technologies, Oleg E Alber, Eugen E Pacher, January 21, 1997: US05596668 (32 worldwide citation)

We have discovered that hydrogen-related loss in silica-based single mode transmission optical fiber can be reduced or eliminated by use of a substrate tube that contains hydrogen getter sites. Exemplarily, substrate tubes according to the invention are doped with Ge or P.


10
David J DiGiovanni, John B MacChesney: Sol-gel doping of optical fiber preform. AT&T Bell Laboratories, M I Finston, E E Pacher, June 23, 1992: US05123940 (30 worldwide citation)

The method includes collapsing a silica-based glass tube to make a preform and drawing fiber from the preform. Prior to collapsing the tube, one or more glass layers are formed on the inner surface of the tube by dip-coating the surface with a sol comprising a metal alkoxide dissolved in an alcoholi ...