Patent Number: 6,434,318

Title: Device and method for variable attenuation of an optical channel

Abstract: A device for variable attenuation of an optical channel includes anelongated core surrounded by a cladding. Optical energy propagating alongthe longitudinal axis of the core is normally confined thereto by thedifference in refractive indices between the core and cladding. Thethermo-optic coefficients of the core and cladding are closely matchedsuch that waveguide confinement is substantially invariant with respect toambient temperature. The device further includes a thermal source arrangedabove the core. The thermal source is operable to generate a temperaturegradient of controllable magnitude along a vertical axis extending throughthe core. The temperature gradient causes reduction of the localrefractive index within the core relative to surrounding regions of thecladding such that a portion of the optical energy is deflected away fromthe thermal source and extracted from the core.

Inventors: Bischel; William K. (Menlo Park, CA), Kowalczyk; Tony C. (Palo Alto, CA)


International Classification: G02F 1/01 (20060101); G02F 1/065 (20060101); G02B 006/00 ()

Expiration Date: 08/13/2014