Photonic variable delay devices based on optical birefringence

USRE38809E1 · kind E1 · reissue

Assignee

• General Photonics Corporation · US

Inventor

• X. Steve Yao · Diamond Bar, US

Key dates

• Filing date: Nov 2, 2001
• Grant date: Oct 4, 2005
• Expiry date: Nov 2, 2021

Classification

• Technology area (CPC —): General

Abstract

Optical variable delay devices for providing variable true time delay to multiple optical beams simultaneously. A ladder-structured variable delay device comprises multiple basic building blocks stacked on top of each other resembling a ladder. Each basic building block has two polarization beamsplitters and a polarization rotator array arranged to form a trihedron; Controlling an array element of the polarization rotator array causes a beam passing through the array element either going up to a basic building block above it or reflect back towards a block below it. The beams going higher on the “ladder” experience longer optical path delay. An index-switched optical variable delay device comprises of many birefringent crystal segments connected with one another, with a polarization rotator array sandwiched between any two adjacent crystal segments. An array element in the polarization rotator array controls the polarization state of a beam passing through the element, causing the beam experience different refractive indices or path delays in the following crystal segment. By independently control each element in each polarization rotator array, variable optical path delays of each…