Methods and apparatus for preventing deadbands in an optical communication system

Abstract

Methods and apparatus for combining, adding, and/or dropping channels in optical communication systems that utilize thin film filters without the creation of deadbands, using fiber Bragg gratings and additional thin film optical filters, are described. According to one aspect of the invention, an optical filter is used to drop a wavelength range from an optical signal. Prior to the optical signal entering the optical filter, one or more fiber Bragg gratings and an optical circulator are used reflects a portion of the communications spectrum which would normally lie with the deadband region of the optical filter. According to another aspect of the present invention, an optical filter is used to combine a first optical signal and a second optical signal to form a combined optical signal. Neither the first optical signal nor the second optical signal includes channels within a deadband region of the optical filter. One or more fiber Bragg gratings and an optical circulator or a coupler are used to add a third optical signal to the combined optical signal. The third optical signal includes signal wavelengths within the deadband region of the optical filter.