HAYDEN HENRY HARRIS
Pilots at Waters Rd, Lyndon Twp, MI

6606187, Aug 12, 2003

Oct 23, 2000

09/694858

Mohammed Nazrul Islam - Ann Arbor MI
Hayden Henry Harris - Chelsea MI

The Regents of the University of Michigan - Ann Arbor MI
Xtera Communications, Inc. - Allen TX

H01S 330

359334, 359124, 35934132, 372 3, 372 6

An apparatus and method are described for exploiting almost the full almost 25 THz of bandwidth available in the low-loss window in optical fibers (from 1430 nm to 1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths should lie in close proximity to the zero-dispersion wavelength of the amplifying fiber. For this intermediate Raman order, spectral broadening will occur due to phase-match with four-wave mixing (if ) or phase-matched parametric amplification (if ).

6567430, May 20, 2003

Sep 21, 1999

09/400414

Mohammed N. Islam - Ann Arbor MI
Michael J. Freeman - Canton MI
Hayden H. Harris - Chelsea MI

Xtera Communications, Inc. - Allen TX
The Regents of the University of Michigan - Ann Arbor MI

H01S 330

372 3, 372 6, 372 94, 372 99

In one embodiment, a Raman oscillator includes at least one laser cavity and a distributed gain fiber positioned in the at least one laser cavity having a single spatial mode over a pumping wavelength to a signal wavelength. The oscillator also includes a coupler adapted to be coupled to a pumping mechanism to pump the distributed gain fiber at the pumping wavelength to obtain an optical signal wherein distributed gain is provided by Raman amplification over at least one cascade order corresponding to the pumping wavelength. A filter is positioned in the at least one laser cavity and has at least one pass band with a transmission peak placed approximately at the at least one cascade order to filter the optical signal to obtain a filtered optical signal having the signal wavelength. The filter has a substantially continuous sinusoidal filter function over at least one period of the filter function.

6239903, May 29, 2001

Apr 25, 2000

9/558300

Mohammed Nazrul Islam - Ann Arbor MI
Hayden Henry Harris - Chelsea MI

Xtera Communications, Inc. - Richardson TX
Regents of the University of Michigan - Ann Arbor MI

H01S 3067, H01S 30933

359337

An apparatus and method are described for exploiting almost the full almost 25 THz of bandwidth available in the low-loss window in optical fibers (from 1430 nm to 1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths. lambda. sub. r should lie in close proximity to the zero-dispersion wavelength. lambda. sub.

6101024, Aug 8, 2000

Mar 24, 1998

9/046900

Mohammed Nazrul Islam - Ann Arbor MI
Hayden Henry Harris - Chelsea MI

Xtera Communications, Inc. - Sunnyvale CA

G02B 626, G02B 642, H01S 330

359334

An apparatus and method are described for exploiting almost the full almost 25 THz of bandwidth available in the low-loss window in optical fibers (from 1430 nm to 1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths. lambda. sub. r should lie in close proximity to the zero-dispersion wavelength. lambda. sub.

6239902, May 29, 2001

May 5, 2000

9/565776

Mohammed Nazrul Islam - Ann Arbor MI
Hayden Henry Harris - Chelsea MI

Xtera Communciations Inc. - Allen TX
Regents of the University of Michigan - Ann Arbor MI

H01S 300, G02B 626, G01B 902

359334

An apparatus and method are described for exploiting almost the full almost 25. sup. TH % of bandwidth available in the low-loss window in optical fibers (from 1430 nm-1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths. lambda. sub. r should lie in close proximity to the zero-dispersion wavelength. lambda. sub.