Filter for Selectively Processing Optical and Other Signals

University of Texas at Dallas
posted on 08/06/2010

A Multi-section Filter for Selectively Processing Optical and other Signals –A Flexible, Low Cost, Efficient, and Standardized Solution

The Technology in Brief

A main tenet of both electrical and optical engineering is the desirability of filtering, sorting and processing information with higher degrees of precision. Ever increasing demand for signal processing and transmission has created the "filter design & development" segment of the optical and semiconductor world. The patented invention provides a unique multi-section filter for processing optical and other signals that can be readily projected from one filter section to another to offer better performance, and swift design and deployment.

Background

In electrical engineering, a significant breakthrough in precision filtering and signal processing came with active filters. Active low pass, high pass, matched, and other varieties of electronic filters show improved performance over their passive counterparts.

Shortcomings of the optical filters currently known is that they are passive and thus they do not have gain, they have lower quality factors than that of active filters of the same order, and they provide limited performance. Another shortcoming is that they are manufactured for specific applications leading to inflexibility and increased costs in design and manufacturing. There is a need for an optical filter that is active and yields higher performance including higher quality factors to enhance tunabilty and provide numerous other benefits. Additionally, it would be very desirable to provide optical filters that could be readily constructed from combinations of conventional or standardized elements or components. Providing these capabilities could significantly enhance flexibility in designing optical filters and reduce costs associated therewith.

Description of Invention

The patented invention offers a multi-section filter for processing optical and other signals that can be directed from one filter section to another. The filter comprises a plurality of active lattice sections, or gain blocks, spaced apart from one another in a linear array, and a surface grating coupler positioned between each pair of adjacent gain blocks in the array. Filters of the invention can be configured in numerous forms, including IIR and FIR filters and both linear and 2D active optical lattice filters. Filter sections are coupled together by means of four direction couplers and surface grating couplers, and may be implemented as GSE photonic integrated circuit devices. The invention provides a filter input components disposed to receive an optical signal, an output component disposed to provide a filtered output, an optical amplifier, and at least one optical delay element with controllable gain and delay characteristics.

Filter sections can be respectively positioned in relation to one another so that an output signal from one element can be projected as an input to another section. These characteristics enable filters of the invention to be configured or embodied in numerous forms, to meet many different application requirements. Moreover, respective filter sections can be readily provided with controllable gain and delay, so that they can be configured as active filters.

Benefits

· Low cost and adaptive optical and electrical signal processing

· Efficient and flexible design and development

· Basic structure can be standardized for fabrication

· Better performance than passive filters of the same order

Applications

· Telecommunication:

- Tunable Gain Flattening Filters

- In dense wave division multiplexed (DWDM) telecommunications systems to add, drop and otherwise sort channels

- Optical Add Drop

- Dispersion compensation which is tunable, eases installation, enables 40Gbps and line side switching on mixed fiber plant, enables low cost, single stage EDFA, small size

· Military and Medicine:

- Encryption/Decryption

- Optical signal processing for making threshold and other decisions

- Advanced sensors

- Neural nets

· Monochromators & Spectraphotometers

IP Status

· United States Patent 7,042,657 Issued May 09, 2006, titled "Filter for selectively processing optical and other signals"

Inventors

· Macfarlane, Duncan L., Professor, The Erik Jonsson School of Engineering and Computer Science, UT Dallas

Licensing Opportunity

This technology is available for exclusive or non-exclusive licensing.