Steven R Sanders

US Patent:

6347100, Feb 12, 2002

Filed:

Oct 15, 1999

Appl. No.:

09/419138

Inventors:

Steven Sanders - Belmont CA
Bernard G. Fidric - Cupertino CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

H01S 330

US Classification:

372 6, 372 5, 372 32, 372 70

Abstract:

A fiber laser uses a mechanism to prevent a thermally induced shift of the gain spectrum to a range that causes the laser to become destabilized when operated at a first signal wavelength. By establishing a nominal gain spectrum that is further from the undesired range than in a conventional laser, a gain spectrum shift does not reach the undesired wavelength range. This may be accomplished by decreasing the reflectivity of a resonant cavity of the laser, such as by angling the reflective end of the cavity. It may also be accomplished by increasing the population inversion of the laser. Using a pump energy reflector to prevent pump energy from exiting the inner cladding of a double-clad version of the laser the fiber may increase population inversion. The fiber length may also be shortened or the diameter of the inner cladding reduced to increase the population inversion before a laser output is achieved. In another embodiment, a thermally induced shift of the gain spectrum into the undesired wavelength range is prevented by using a controlled temperature environment, such as a housing with a cooling mechanism.

US Patent:

6356574, Mar 12, 2002

Filed:

Jan 29, 1999

Appl. No.:

09/240361

Inventors:

Richard R. Craig - Victoria, CA
Robert L G. Waarts - Fremont CA
David F. Welch - Menlo Park CA
John G. Endriz - Belmont CA
Dirk J. Kuizenga - Sunnyvale CA
Steven Sanders - Palo Alto CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

H01S 30933

US Classification:

372 75, 372 50

Abstract:

A multistage optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources for pumping a single fiber laser pump source. A second level of redundancy deals with redundancy of a plurality of fiber laser pump sources for pumping a plurality of serially connected injection signal fiber amplifiers forming the multistage amplifier system. If one of fiber pump sources should fail, increased pumping power is available from the remaining fiber pump sources via their respectively connected amplifier stages. A third level of redundancy deals with redundancy in the employment of multiple single mode laser emitters on the same chip or bar sufficiently segmented and/or electrical isolated so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar.

US Patent:

6424663, Jul 23, 2002

Filed:

Aug 16, 1999

Appl. No.:

09/375841

Inventors:

Bernard Fidric - Cupertino CA
Steven Sanders - Belmont CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

H01S 3067

US Classification:

372 6

Abstract:

A fiber optic gain system has output power monitoring and control using the detected level of side light emitted through the cladding of the gain fiber. The fiber is wound on a spool that is provided with an opening adjacent to the fiber cladding. A photodetector is mounted to the spool at an opposite side of the opening, and detects side light that is transmitted through the opening. An output signal from the photodetector is indicative of the output power or the gain of the system, and may be used for monitoring and/or to adjust the power generated by a pumping source for the system. This allows feedback control of the system that helps to stabilize the output power or gain. A filtering element may also be used to exclude certain undesired wavelengths from the side light being detected.

US Patent:

6434302, Aug 13, 2002

Filed:

Mar 4, 1999

Appl. No.:

09/262942

Inventors:

Bernard G. Fidric - Cupertino CA
Vincent G. Dominic - Fremont CA
Steven Sanders - Belmont CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

G02B 626

US Classification:

385 43, 385 48

Abstract:

Optical couplers functioning, for example, as fiber optic combiners or fiber optic splitters for multimode fibers are disclosed for coupling, for example, the light output of a plurality of multimode laser sources into a multimode output fiber or fibers. Coupling combinations include multimode fibers to multimode fiber or fibers (MMFs/MMF(s)) or multimode fibers/single mode fiber to double clad fiber (MMFs/SMF/DCF). Improvements are disclosed in coupling efficiency and the power distribution uniformity of optical power into an output fiber, such as double clad fiber inner cladding or multimode fiber core, from multiple multimode input fibers. Power distribution uniformity can be significantly improved by having the multimode fiber bundled region taper converging down to a minimum waist having a diameter, D , where the input light from the multimode input fibers substantially fills the entire numerical aperture (NA) of an air-clad region of the couple, where NA 1, followed by an adiabatic diverging taper up to the nominal cladding or core diameter, D , of the output fiber or combined fibers.

US Patent:

6477295, Nov 5, 2002

Filed:

Jan 20, 2000

Appl. No.:

09/488166

Inventors:

Robert J. Lang - Pleasanton CA
Robert G. Waarts - Fremont CA
Ian J. Booth - Sooke, CA
David M. Giltner - Fremont CA
Steven Sanders - Palo Alto CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

G02B 626

US Classification:

385 31, 385 27, 385127, 372 6

Abstract:

Apparatus for coupling light into a fiber, such as a double clad fiber (DCF) having a core having a refractive index n , surrounded by an inner cladding having refractive index n which is surrounded by an outer cladding having a refractive index n , where n n n. An optical coupler medium, referred to as a Fiber Space Division Multiplexor or FSDM, is formed on an exposed portion of the fiber inner cladding at a position along the length of the fiber without interfering with the continuity of its core and provides at, at least one position, the imaging of light external of the fiber into the inner cladding interface and its waveguiding with the inner cladding of the fiber. The FSDM coupler comprises an optical material in optical contact or integrated with the inner cladding and having a refractive index substantially equal to n. The coupler medium may also be employed with a fiber having no core and where the inner cladding would function as a multimode core. Also, disclosed are formed reflectors for reflecting back residual, unabsorbed pump light backward into the DCF inner cladding for absorption within the core doped with a rare earth active material.

US Patent:

6603593, Aug 5, 2003

Filed:

Sep 19, 2001

Appl. No.:

09/956595

Inventors:

Bernard G. Fidric - Cupertino CA
Steven Sanders - Belmont CA
Vincent G. Dominic - Fremont CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

H01S 300

US Classification:

359334, 3593413

Abstract:

An optical transmission system that employs a Raman amplifier including a Raman pump for introducing depolarized pump light into the fiber. The pump includes an optical source generating a polarized optical pump signal, an optical splitter that splits the pump signal into a first pump portion and a second pump portion, and a beam combiner that combines the first pump portion and the second pump portion into the depolarized pump light. Further, the pump includes a delay device, such as a length of fiber, that causes the first pump portion to propagate farther from the beam splitter to the beam combiner than the second pump portion. The length of fiber is longer than the coherence length of the pump signal.

US Patent:

6870973, Mar 22, 2005

Filed:

Oct 2, 2002

Appl. No.:

10/263109

Inventors:

Bernard G. Fidric - Cupertino CA, US
Shaoping Lu - Palo Alto CA, US
Steven Sanders - Belmont CA, US
Bruno Acklin - Mountain View CA, US

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

G02B006/00

US Classification:

385 11

Abstract:

A Lyot depolarizer for depolarizing a laser with multiple longitudinal modes comprises two segments of PM fiber optimized for length as a function of the longitudinal mode spacing of the laser source, and not as taught in the prior art as a function of the laser coherence length. The present invention has found secondary coherence peaks in the coherence function of a multiple longitudinal mode source, which can significantly worsen the DoP if the PM fiber lengths are significantly extended beyond optimum, contrary to the teaching in the prior art. The present invention makes use of the periodic structure of the source spectrum by converting half the longitudinal modes to an orthogonal polarization state. As a result a significantly shorter fiber depolarizer is needed than for a single longitudinal mode source. Greater temperature stability is achieved by properly adjusting the lengths of both segments of PM fiber.

US Patent:

6963681, Nov 8, 2005

Filed:

Jun 30, 2003

Appl. No.:

10/611784

Inventors:

Erji Mao - Campbell CA, US
Stuart MacCormack - Mountain View CA, US
Greg Roth - Santa Ana CA, US
Steven Sanders - Belmont CA, US

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

G02B006/26
G02B006/42

US Classification:

385 27, 359334, 3593411, 35934141, 35934142

Abstract:

The invention relates to a method for automatic dynamic gain control in optical Raman amplifiers and an optical Raman amplifier adapted for the same. The present invention has found that in multiple pump Raman amplifiers a substantially linear relationship exists between total amplified signal power and pump power for each of different wavelength pumps, in order to maintain an original gain profile and gain levels for an optical link with a fully loaded channel configuration, in response to dropped channels. In accordance with the method, and an amplifier programmed to practice the method, a set of pump power values and signal level values required to maintain the characterized gain profile and gain levels for a plurality of channel loading configurations are pre-established for the each pump wavelength. A linear function from each set of pre-established values is derived for each pump wavelength. Advantageously, a single photodiode can replace a costly and complex channel monitor for providing signal responsive pump control.