Ursula M Keller

US Patent:

52375773, Aug 17, 1993

Filed:

Nov 6, 1991

Appl. No.:

7/788641

Inventors:

Ursula Keller - Highlands NJ
David A. B. Miller - Fair Haven NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 3098
H01S 310

US Classification:

372 11

Abstract:

Saturation intensity and loss of a saturable absorber are substantially independently regulated by positioning the saturable absorber element within a Fabry-Perot etalon defined by first and second reflective elements so that the saturable absorber element responds to light at optical wavelengths in the anti-resonant portion of the Fabry-Perot spectral response, that is, between optical wavelengths corresponding to resonance peaks. The resulting combination of elements is called a Fabry-Perot saturable absorber. Thickness of the saturable absorber element substantially sets the loss of the Fabry-Perot saturable absorber while changes in the reflectivity of the first reflective element onto which the light is incident substantially determines the saturation intensity (degree of nonlinearity) and assists in compensating loss of the saturable absorber element. In one exemplary embodiment, a high reflectivity first reflective element is positioned on the end of the saturable absorber element facing the incident optical radiation while a high reflectivity second reflective element is positioned on the opposite end of the saturable absorber. Dielectric material layers form the first reflective element whereas semiconductor layers form the second reflective element.

US Patent:

53454545, Sep 6, 1994

Filed:

Jan 27, 1993

Appl. No.:

8/010029

Inventors:

Ursula Keller - Highlands NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 3098

US Classification:

372 12

Abstract:

The advantages of both active and passive modelocking techniques are realized within a single device by providing a p-i-n modulator formed at antiresonance within a Fabry-Perot etalon. The p-i-n modulator actively modulates light within the laser cavity by introducing periodic loss in response to changing voltages applied to the modulator. The p-i-n modulator includes an intrinsic region that is disposed between a p-doped region and an n-doped region. The modelocking performance of the p-i-n modulator is enhanced by the saturable absorber action of the intrinsic region.

US Patent:

50070592, Apr 9, 1991

Filed:

May 15, 1990

Appl. No.:

7/523622

Inventors:

Ursula Keller - Atlantic Highlands NJ
Wayne H. Knox - Rumson NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 3098

US Classification:

372 18

Abstract:

Modelocking of a solid state laser such as a Ti:Al. sub. 2 O. sub. 3 laser is achieved by employing an external cavity defined by spatially separated reflective elements wherein at least one of the reflective elements exhibits a nonlinear characteristic in response to an impinging light beam. Exemplary nonlinear reflective elements are described using bulk semiconductor material or semiconductor quantum well structures integrated with a rear reflector such as a stack of quarter-wave thick dielectric or semiconductor material. Tuning control of the nonlinear reflective element may be introduced with temperature control arrangements and with mechanical translation arrangements in conjunction with lateral band gap engineering of the semiconductor material.

US Patent:

52788555, Jan 11, 1994

Filed:

May 11, 1992

Appl. No.:

7/880928

Inventors:

Ursula Keller - Highlands NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 319

US Classification:

372 44

Abstract:

Extended wavelength tunability is achieved in a saturable absorber for applications such as modelocking lasers by realizing a semiconductor structure having a tapered energy bandgap profile in a portion of the saturable absorber wherein the profile is given as a function of the distance along the propagation axis of the saturable absorber. For certain applications, at least one mirror is monolithically integrated with the saturable absorber.