U.S. Patent No. 7,899,330, issued on March 1, 2011 to DiCon Fiberoptics, Inc. of Richmond, CA, discloses a tunable optical filter for optical communication networks.
Conventional optical communication networks utilize optical add/drop multiplexers (OADMs) with fixed optical filters to select/remove a particular wavelength from the multiple-wavelength optical signal. However, there’s a need for reconfigurable OADMs (ROADMs) with tunable optical filters which provide flexibility by allowing dynamic selection of the wavelength being manipulated. The ’330 patent discloses a tunable optical filter in which the received multiple-wavelength light is diffracted by cascaded optical diffraction gratings, and a microelectromechanical system (MEMS) mirror reflects the diffracted light again onto the cascaded optical diffraction gratings. In this way, the light is diffracted twice and only light having the selected wavelength propagates out of the optical filter to an output port. According to the ’330 patent, this configuration “results in a compact device structure and allows the use of low-cost gratings” with low power consumption and high reliability.
According to its website, DiCon “is one of the world’s largest suppliers of passive components, modules and test instruments for the fiberoptic communications industry.” DiCon markets tunable optical filters that are touted as having a compact form factor and superior optical performance, but its website does not provide information regarding whether the configuration of the ’330 patent is being used in these products. The company continues to develop other optical devices based on this technology.
According to the USPTO database, DiCon Fiberoptics received two U.S. patents in 2010, and the ’330 patent is the company’s first U.S. patent in 2011.
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