Magnetically tunable optical fiber gratings

• Main Authors: JIN, SUNGHO, STRASSER, THOMAS A, LEMAIRE, PAUL JOSEPH
• Format: Patent
• Language: English; French; German
• Published: 09.05.2001
• Edition: 7
• 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

In accordance with the invention, a tunable fiber grating comprises a fiber grating secured between a pair of magnets so that magnetic force (repulsive or attractive) applied to the magnets is transmitted to the grating. An electromagnet is disposed adjacent the magnets for applying the field to magnetize them. Control of the current applied to the electromagnet permits control of the force transmitted to the fiber grating and, thus, control of the grating strain, spacing and reflection frequency. In a preferred embodiment the electromagnet is actuated to produce magnetic pulses which control the remanent force between the two magnets, eliminating the need for continuous power. An add/drop multiplexer employing the tunable gratings is described.