1
Andrew R Chraplyvy, Jonathan A Nagel, Robert W Tkach: Optical transmission system equalizer. AT&T Bell Laboratories, E Weiss, July 6, 1993: US05225922 (134 worldwide citation)

Increasing the capacity of an existing lightwave transmission system can be accomplished by either increasing the bit rate or adding wavelength-multiplexed channels. Recent advances in erbium-doped fiber amplifier technology make the wavelength division multiplexed option particularly attractive. Un ...


2
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 ...


3
Daniel A Fishman, Jonathan A Nagel, Yong Kwan Park: Reduction of stimulated brillouin scattering in a fiber optic transmission system. AT&T Bell Laboratories, Robert P Marley, July 12, 1994: US05329396 (37 worldwide citation)

A technique for reducing the power threshold at which stimulated brillouin scattering ("SBS") occurs within an optical fiber by directly modulating a conventional laser generating an optical signal propagated along that fiber. The modulation is accomplished by employing an alternating waveform to in ...


4
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.


5
Jonathan A Nagel, Sergey Y Ten, Carl A B Clausen: System and method for controlling spectral distribution of output power in a Raman amplifier. Tyco Telecommunications, February 10, 2004: US06690504 (24 worldwide citation)

A system and method for controlling gain shape in a Raman amplifier including a plurality of pumps. The pumps produce a spectral distribution of output power characteristic. A feedback control system provides one or more feedback control signals in response to the amplifier output for adjusting pump ...


6
Jonathan A Nagel, Samia M Bahsoun: In-line two-stage erbium doped fiber amplifier system with in-band telemetry channel. AT&T, February 28, 1995: US05394265 (12 worldwide citation)

The present invention is an in-line multi-stage erbium doped fiber amplifier system for use in fiber optic communication systems. The system comprises two cascaded erbium doped fiber amplifiers (12), (14) separated by an drop/add device (20) for filtering out the amplifier spontaneous emission noise ...


7
Michael Herbert Eiselt, Jonathan A Nagel: Polarization mode dispersion compensation. AT&T, July 27, 2004: US06768875 (10 worldwide citation)

Methods and systems for PMD compensation in an optical communication system are implemented by transmitting multiple optical signals through a common optical conduit to an optical compensator that adjustably rotates the polarization states of the multiple optical signals and transmits the rotated op ...


8
Stephen G Evangelides Jr, Jonathan A Nagel: COTDR arrangement with swept frequency pulse generator for an optical transmission system. Huawei Marine Networks, Leydig Voit & Mayer, January 11, 2011: US07869708 (9 worldwide citation)

A method and apparatus is provided for obtaining status information from a given location along an optical transmission path. The method begins by generating a cw probe signal having a prescribed frequency that is swept over a prescribed frequency range. The cw probe signal is transmitted over the o ...


9
Jonathan A Nagel, Samia M Bahsoun: In-line two-stage erbium doped fiber amplifier system with in-band telemetry channel. AT&T, January 2, 1996: US05481399 (8 worldwide citation)

The present invention is an in-line multi-stage erbium doped fiber amplifier system for use in fiber optic communication systems. The system comprises two cascaded erbium doped fiber amplifiers (12), (14) separated by an drop/add device (20) for filtering out the amplifier spontaneous emission noise ...


10
Jean Marc Pierre Delavaux, Jonathan A Nagel: Optical amplifier using optical circulator and fiber amplifier. Lucent Technologies, Richard Laumann, Lester H Birnbaum, October 13, 1998: US05822113 (8 worldwide citation)

An optical amplifier achieves multistage amplification with a four port optical circulator with fiber amplifiers and Faraday rotators and mirrors connected to at least two of the ports. The fiber amplifiers permit the signal to pass through the fiber amplifiers twice.