摘要:
A tunable chromatic dispersion compensator for optical communication systems is disclosed. An optical grating, such as a fiber Bragg grating, nonchirped, linearly chirped or non-linearly chirped, is strained to alter the dispersion compensator characteristics, preferably with a gradient-generating body bonded onto the length of the fiber grating. The body may be latchably strained so that the grating characteristics may be changed or tuned while avoiding use of a continuous power supply. Various optical networking applications using such dispersion compensating devices are also disclosed.
摘要:
A tunable chromatic dispersion compensator for optical communication systems is disclosed. An optical grating, such as a fiber Bragg grating, non-chirped, linearly chirped or non-linearly chirped, is coated on its outer surface with a coating have a variable diameter and strained is applied to the fiber. The fiber may be latchably strained so that the grating characteristics may be changed or tuned while avoiding use of a continuous power supply. Various optical networking applications using such dispersion compensating devices are also disclosed.
摘要:
A method for making a chirped grating device capable of a broad bandwith for optical communication systems is disclosed. An intrinsically-chirped optical grating is externally strained to alter the range of chirping. The external strain may be induced by a gradient-generating body bonded onto the length of the fiber grating that may be latchably strained so that the grating characteristics may be changed or tuned while avoiding use of a continuous power supply. Various optical networking applications using such dispersion compensating devices are also disclosed.
摘要:
A programmable and latchable device for wavelength shifting and chromatic dispersion compensating is disclosed. An optical grating such as a Bragg grating, a nonchirped grating, or a linearly or non-linearly chirped grating, is magnetostrictively strained to alter the dispersion compensator characteristics. In a preferred embodiment, a gradient magnetostrictive body is bonded along its length to the fiber grating. In yet another preferred embodiment, a magnetostrictive body is bonded onto the length of the fiber grating, and a gradient generating, programmable and latchable magnet component is placed adjacent the magnetostrictive body. The body is then latchably strained to a desired level by controlling the extent of magnetization in the magnetostrictive material and the magnet so as to induce or enhance chirping characteristics in the grating. Various optical applications using such are disclosed.
摘要:
The invention is a reconfigurable optical grating device using force from programmable magnets to alter the mechanical strain, preferably a tensile strain, on the gratings so as to induce a latchable change in grating periodicity using a pulse or short-duration current. It includes apparatus for limiting the maximum strain applied to the grating so that the fiber does not fracture, and it provides strain without rotation or twisting of the fiber grating. In preferred embodiment it provides control of magnetic force so as to accurately obtain a predetermined amount of strain and hence wavelength shift in the grating with a minimal amount of electrical power. The inventive structure is useful, e.g. for wavelength division multiplexed optical communication system comprising wavelength channel add/drop devices and/or dynamically gain-equalized amplifiers.
摘要:
A variable attenuator device is disclosed that may be magnetically and latchably controlled such that it does not require a continuous power supply to maintain a particular loss level. The variable attenuator comprises two optical components disposed in spaced apart relation to define a gap between them and a magnetic shutter positioned within the gap. The shutter is movable, due to its magnetic properties, from a first position to at least a second position, where the second position may be within, partially within, or outside of the gap. A mechanism is provided for magnetizing or actuating the shutter to cause it to move from the first position to the at least second position. When the shutter is in the first position, it causes a certain amount of attenuation in the signal being transmitted between the two optical components, and when it moves to the at least second position, a different amount of attenuation is caused, such that movement of the shutter causes a variation in the attenuation. With this attenuator, the variation in attenuation may be achieved via coupling loss while the optical components (e.g., mating fibers), are maintained in a fixed position, thereby avoiding difficulties associated with fiber movement.
摘要:
A temperature compensated optical fiber grating device comprises a longitudinally extending optical fiber grating having a length and a packaging assembly for the grating comprising a first longitudinally extending body of material having a first coefficient of thermal expansion (CTE) and second and third longitudinally extending bodies of material having CTE's lower than the first CTE. The three bodies are mechanically attached at alternate ends to form a composite structure having an effective negative CTE between two ends to which the grating is attached. The resulting grating device can be made in compact form having an overall length less than 30% more than the grating (and preferably less than 10%) and can reduce the temperature dependent wavelength change in the grating to less than 0.2 nm/100.degree. C. and preferably less than 0.05 nm/100.degree. C. In a preferred embodiment, the packaging bodies include a cylinder enclosing the grating.
摘要:
In accordance with the invention, a device for controlling alignment between two optical devices comprises a mobile magnet attached to a mobile optical device and a plurality of programmable magnets for moving the mobile magnet (and attached optical device) in relation to a second optical device. In preferred embodiments, the programmable magnets are latchable.
摘要:
In accordance with the invention, a tunable laser uses magnets to apply mechanical strain on fiber Bragg grating reflectors or laser cavities in order to induce a change in lasing wavelength. The strain can be tensile or compressive. The tunable laser comprises a laser cavity including a laser material for emitting light in response to stimulating light and two end reflectors one or more of which can be a Bragg grating. In preferred embodiments, latchable programmable magnets vary the grating periodicity and/or cavity length in a controlled, accurate manner so as to achieve desired tuning of the laser over a broad range of wavelengths. The latchable magnets hold the wavelength in the shifted position without the need for sustained power.
摘要:
The invention discloses digitally tunable optical grating device using force between switchable and nonswitchable magnets to reconfigure the mechanical strain, preferably a tensile strain, or gratings so that a pulse or short-duration current can induce a latchable change in grating periodicity. Preferred embodiments include fiber gratings with magnet gaps dimensioned for limiting the maximum strain applied to the grating and guides for providing strain without rotation or twisting. The magnets provide an accurately predetermined amount of strain and hence provide a latchable wavelength shift in the grating with a minimal amount of electrical power. The device is especially useful in WDM communication systems, particularly for adding or dropping channels and for dynamically equalizing amplifier gain.