Annapolis Junction, MD, April 21, 2004--Little Optics, Inc., which has invented and patented a glass high-index optical waveguide material system, Hydex, for planar lightwave circuit (PLC) fabrication, has made available 8-bit programmable delay lines based on the technology. The circuit has a series of crossbar switches that selectively route signals through either a planar time-delay element or a bypass. Applications include true-time-delay signal processors for phased-array antennas, optical-time-domain multiplexing, optical-clock distribution, and optical buffering within all-optical routers.
The company uses a "pick-and-place" stepper lithography strategy to selectively place spirals of arbitrary length onto a common bus structure. A library contains more than 400 long-path-length waveguide spirals ranging from 0.05 to 20 cm (corresponding to time delays from 3 ps to 1.2 ns) that can be integrated onto a chip that is less than 1 cm2. Using the 8-bit architecture, a device with a maximum time delay of 2.4 ns can be realized using standard photonic elements. Longer delays or devices with specific requirements can be designed if not available in the standard device library. Mode transformers are integrated into the PLC for efficient coupling into conventional single mode fibers.
Little Optics was founded in July 2000 to design and develop integrated optical devices for communications, semiconductor, defense electronics, and bio/chem sensor applications. The company's 5x-stepper lithography allows the fabrication of devices such as microring resonators, multilayer optical vias, polarization beamsplitters, polarization converters and rotators, tunable amplitude and phase filters, and crossbar switches. These elements can be stitched together to build customized circuits. On-chip mode transformers can match the modal profile of high-index waveguides to conventional single-mode fiber.