Patent attributes
A low cost compact 3-port single-channel OADM with improved optical isolation is provided in which the I/O fibers and add/drop fiber are arranged on the same side. The 3-port OADM includes a 3-fiber pigtail and an angled reflector that together eliminate the second fiber collimator—one set of lenses and ferrules. The reflector is positioned behind and at angle to the free-space filter such that the add/drop optical signals are reflected back through the collimating lens to the appropriate fiber. In a drop filter, a signal is dropped from the optical signal on the input fiber and reflected back to the add/drop fiber. In an add filter, a signal is inserted from the add/drop fiber and reflected back to the output fiber. A 4-port OADM can be made by fiber-splicing a pair of 3-port OADMs.
