US 6,035,080 AGranted

Reconfigurable add-drop multiplexer for optical communications systems

OwnerCharles Howard Henry, Gadi Lenz +4inventors

InventorsCharles Howard Henry, Gadi Lenz, Yuan P. Li, Christi Kay Madsen, Herman Melvin Presby, Ronald Edward Scotti

Life of this patent

Estimating the term…

Loading patent…

Abstract

In accordance with the invention, an optical multiplexer includes at least one reconfigurable add-drop unit that can add-drop one channel out of a large set by switching the light path through one of a set of fixed add-drop filters. Reconfiguration is done by switching from the add-drop filter path to a bypass path, changing to a different add-drop filter and then switching back. The phase delay of the bypass path is adjusted to maintain nearly maximum transmission during switching. The selection among add-drop filters is done by sliding an integrated optic chip with the set of add-drop filters between input and output waveguides. The reconfigurable add-drop multiplexer unit is latchable, passive between reconfigurations, and has low intrinsic insertion loss. Plural units in series can add/drop plural channels.

Claims12

Dependent claims

A reconfigurable add-drop multiplexer for a multi-channel optical communications system comprising:

a plurality of add-drop filters responsive to respectively different optical signal channels of said system,
a first optical path for coupling an optical multichannel signal through an add-drop filter of said plurality;
a second optical path for coupling an optical signal through an unfiltered bypass path, said second path having an optical pathlength equal to the first:
a first switch for optically switching an optical signal between said first path and said second path without interrupting said signal;
and
a second switch for changing the add-drop filter in said first path while said optical signal is coupled to said second path and an optical phase shifter in said first path or said second path for maintaining the relative phase difference between the first and second paths whereby said multiplexer can be reconfigured to add or drop different signal channels without the loss of bits.

3 more elements

Dependencies are inferred from the claim text.