Richard D Sharp

US Patent:

6661963, Dec 9, 2003

Filed:

Jul 31, 2001

Appl. No.:

09/919704

Inventors:

Richard Sharp - Wayland MA
Vincent Scalesse - Tewksbury MA
Ravindra N. Kolte - Chelmsford MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

G02B 600

US Classification:

385140, 385 15, 324 711, 3562431, 2502521

Abstract:

A method and apparatus for controlling the attenuation level of a semiconductor VOA relative to an absolute temperature of the VOA without the use of a power monitor is provided. The method includes the step of providing a variable optical attenuator for attenuating the optical signal. The variable optical attenuator is instructed to maintain the desired attenuation level of the optical signal. The temperature of the variable optical attenuator is periodically sensed, and a required voltage level is determined to achieve the desired attenuation level based at least partially on the periodically sensed temperature of the VOA. The method can further include the step of increasing and decreasing a voltage to the VOA to achieve the required voltage level and thus the desired attenuation level.

US Patent:

6741761, May 25, 2004

Filed:

Jun 28, 2001

Appl. No.:

09/896417

Inventors:

Richard Sharp - Wayland MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

G02F 1035

US Classification:

385 2, 385 3, 385 4, 359246

Abstract:

A method for improving the bit error rate of a modulated optical signal transmitted over single mode fiber is provided. The modulating voltage supplied to a single arm or alternatively to both arms of a Mach-Zehnder modulator is increased to result in a reduced extinction ratio of the modulated optical signal. This results in an optimum optical signal with a reduced bit error rate at a receiver coupled to the Mach-Zehnder modulator.

US Patent:

56663730, Sep 9, 1997

Filed:

Feb 6, 1996

Appl. No.:

8/597330

Inventors:

Richard C. Sharp - Wayland MA
Derek E. Spock - Watertown MA
Noren Pan - Newton MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

H01S 3098
H01L 2170

US Classification:

372 18

Abstract:

A laser having a gain medium disposed in a resonant cavity having a pair of end reflectors. One of such reflectors has a reflectivity lower than the reflectivity of the other one of the reflectors. The reflectors are arranged to provide a single ended output for the cavity through the one of the reflectors having the lower reflectivity. A saturable absorber is formed on the one of the reflectors having the lower reflectivity. With such an arrangement, fabrication of the saturable absorber on the single ended output coupler is greatly simplified. The gain medium is a doped fiber and the saturable absorber formed on the one of the reflectors having the lower reflectivity is affixed to an end of the doped fiber gain medium. With such an arrangement, a highly efficient, relatively low cost, mode locked laser is provided.

US Patent:

49455435, Jul 31, 1990

Filed:

Sep 1, 1989

Appl. No.:

7/401706

Inventors:

Richard C. Sharp - Concord MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

H01S 322
H01S 3223

US Classification:

372 55

Abstract:

A carbon dioxide (CO. sub. 2) waveguide laser is used to provide coherent infrared radiation. The mixture of gases in the laser includes helium, nitrogen, carbon dioxide, carbon monoxide, xenon and heavy hydrogen (deuterium). Carbon dioxide is the gain medium of the laser. During operation of the laser, a significant fraction of the CO. sub. 2 dissociates to CO and O. sub. 2. In the present invention, deuterium (D. sub. 2) in the presence of excess CO catalyzes the recombination of CO and O. sub. 2 back to CO. sub. 2, thus yielding significantly increased power output from the laser. The presence of D. sub. 2 also sustains a long sealed life from the CO. sub. 2 laser at an enhanced power output level.

US Patent:

62822241, Aug 28, 2001

Filed:

Jan 13, 1999

Appl. No.:

9/229817

Inventors:

Irl W. Smith - Concord MA
Richard C. Sharp - Wayland MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

H01S 3083

US Classification:

372 94

Abstract:

A non-planar Q-switched ring laser system including a ring laser having a gain medium and a closed optical path lying in at least two distinct planes, and a Q-switch in the closed optical path for automatically varying the loss in the closed optical path.

US Patent:

20180059005, Mar 1, 2018

Filed:

May 26, 2017

Appl. No.:

15/605962

Inventors:

- Burlington MA, US
Donald Kuehl - Windham NH, US
Eugene Yi-Shan Ma - Newton MA, US
Richard C. Sharp - Wayland MA, US

International Classification:

G01N 21/17
G01N 30/74
G01N 30/60
G01N 21/27
G01N 30/02

Abstract:

A fluid analyzer for analysis of analyte bearing fluids includes an optical source and an optical transducer defining a beam path of an optical beam; a fluid flow cell with a fluid channel, wherein an interrogation region is defined in which the optical beam interacts with the fluids resulting in transducer output signals; and a controller configured and operative to control operation of the fluid analyzer. In one example the fluid analyzer is controlled to (1) combine a third fluid with the first or second fluid, (2) conduct the first fluid and second fluid through the interrogation region in first and second intervals respectively, (3) measure the transducer output signals during the first and second time intervals, and (4) determine, from the transducer output signals measurement, values of the first and second fluids and an indication of a physical property of the first fluid.