Patent ID: 6870989

Claim:
A method for performing add/drop functions of light signals in an optical fiber light transmission system, comprising the steps of providing an add/drop light signal junction having an input light path, an output light path, an add light path, and a drop light path, a group of bandpass light filters, wherein each of the group of bandpass light filters is optically different from due other bandpass light filters and is operable to reflect a respective reflected wavelength band and transmit a respective transmitted wavelength band, and a filter module positioned to selectively place any of the group of bandpass light filters into the add/drop light signal junction, the filter module comprising a movable support on which the group of bandpass light filter is mounted, and a drive mechanism operably connected to the movable support to controllably move a selected one of the bandpass light filters into the input light path; accomplishing a first add/drop function by first positioning a first selected one of the bandpass light filters into the add/drop light signal junction using the drive mechanism, directing an input light beam on the input light path onto the first one of the bandpass light filters, performing the first add/drop function on the input light bean relative to a first band light signal in a first wavelength band, wherein the first add/drop function may be any one of a first light signal add, a first light signal drop, or both a first light signal add and a first light signal drop, and removing the first selected one of the bandpass light filters from the input light path using the drive mechanism; and thereafter accomplishing a second add/drop function by second positioning a second selected one of the bandpass light filters into the add/drop light signal junction using the drive mechanism, directing the input light beam on the input light path onto the second selected one of the bandpass light filters, and performing the second add/drop function on the input light beam relative to a second-band light signal in a second wavelength band, wherein the second add/drop function may be any one of a second light signal add, a second light signal drop, or both a second light signal add and a second light signal drop.