Ilx Lightwave Corporation

University of Colorado

Government of the United States of America, As Represented by the Secretary of Commerce

Terry Brown

Jason Ensher

Christopher Stephen Wood

Jun Ye

Dhruv Kedar

John M Robinson

William R Milner

Colin J Kennedy

Eric G Oelker

Tobias Bothwell

The frequency stability of an optical local oscillator is improved by locking a laser to a silicon Fabry-Perot cavity operating at a temperature near 124 K, where the coefficient of thermal expansion of silicon is near zero. The cavity is mounted inside a cryostat housed in a temperature-stabilized vacuum system that is surrounded by an isolating enclosure and supported by an active vibration platform. Laser light is steered with a superpolished mirror toward a superpolished focusing optic that couples the laser light into the cavity. Light reflected from the cavity is used to stabilize the laser via the Pound-Drever-Hall technique, while light transmitted through the cavity is used to stabilize the laser power. A resonant transimpedance amplifier allows the laser power to be reduced, which reduces heating of the cavity caused by residual absorption of the light.

Optical local oscillator for all-optical time scales, and associated timekeeping methods

The invention provides a polarization controller to set the state of polarization (SOP) of light in an optical fiber. A plurality of piezoelectric squeezers couple with an electronic drive to apply compression forces to the fiber. The drive applies voltage signals to the squeezers and monitors one or more of (a) a voltage across the squeezer, (b) a capacitance change with the fiber, (c) a force applied to the squeezer, (d) a force applied to the fiber, and (e) a resonance of one or more squeezers. Feedback from one or more of (a)-(e) is used to modify the applied voltage signals in control of the SOP.

Feedback polarization controller

The invention provides a polarization scrambler to rapidly change the state of polarization of light transmitted through a single mode fiber such that a substantial portion of the Poincare sphere is covered. A plurality of piezoelectric squeezers couple with an electronic drive. Each squeezer resonates in response to drive signals from the electronic drive to induce radial compression forces on the fiber. The drive signals remain resonant with each squeezer, at frequencies of about 100 kHz, through a feedback loop for each of the squeezers and the electronic drives. Coverage over the Poincare sphere typically occurs in less than about 100 milliseconds, and preferably less than 1 millisecond.

Resonantly driven fiber polarization scrambler

Growing community of inventors

Lafayette, CO, United States of America

Terry Brown