Optical add-drop multiplexer having an interferometer structure

• Main Authors: LI, YUAN P, DOERR, CHRISTOPHER RICHARD
• Format: Patent
• Language: English; French; German
• Published: 22.09.1999
• Edition: 6
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; FREQUENCY-CHANGING; MULTIPLEX COMMUNICATION; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TRANSMISSION

An optical add-drop multiplexer (ADM) Ä60Ü avoids waveguide crossings by being constructed in the form of a Mach-Zehnder interferometer having a demultiplexer/multiplexer (demux/mux) pair Ä300, 400Ü in each of its arms. Each demux/mux pair is interconnected by coherent connecting paths Ä70, 80Ü having heating elements Ä65, 66Ü for increasing the path length of selected connecting paths. Waveguide optical couplers Ä61, 62Ü having asymmetric transfer functions are used at the input and output of the ADM. These couplers cooperate with the activated heating elements to add and/or delete a selected optical channel to/from an optical transmission path. Each coherent connecting path includes a number of waveguides. The end-to-end transmission characteristic of the ADM through each individual waveguide has a Gaussian shape. These Gaussian shapes are designed intersect at their -3 dB wavelengths so that the end-to-end transmission characteristic of the ADM is flat.