Massachusetts Institute of Technology

Other

Ipg Photonics Corporation

Peter Colin Reeves-Hall

George Buabbud

Juan Montoya

Dale H Martz

Igor Samartsev

Daniel J Ripin

Cristiano Mornatta

Christopher Aleshire

A photonic lantern couples light from several fibers or fiber cores into one or more fibers or fiber cores. Photonic lanterns are often used to combine several lower-power beams into a single higher-power beam. They can also be used to couple light from multi-core fibers into single-mode, multi-mode, or other multi-core fibers. By modulating the phases of the input beams, the light can be switched from output to output&#x2014;for example, between output cores of a multi-core output fiber. If desired, the beams can also be amplified using an active fiber in or coupled to the photonic lantern. A first photonic lantern couples signal light and pump light into the core and cladding, respectively, of an active multi-mode or multi-core fiber. And the active multi-mode or multi-core fiber couples amplified signal light into output fiber(s) via a second photonic lantern.

Photonic lantern structures and devices

In a draw tower for producing a length of optical fiber, a preform feed accepts a preform into the draw tower and a furnace downstream of the preform feed heats the preform. Fiber shaping hardware downstream of the thermal furnace is controlled by fiber shaping control electronics to produce along the fiber at least one low-absorption fiber section having a first cross-sectional geometry of the inner cladding layer corresponding to a first level of absorption of input pump light from the inner cladding layer to the core and at least one high-absorption fiber section having a second cross-sectional geometry of the inner cladding layer corresponding to a second level of absorption of input pump light from the inner cladding layer to the core that is greater than the first level of absorption. A tractor downstream of shaping hardware pulls the preform through the furnace and shaping hardware.

Control of heating in active doped optical fiber

An electro-optic beam controller, material processing apparatus, or optical amplifier, and corresponding methods, can include an actively controlled, waveguide-based, optical spatial mode conversion device. The conversion device can include a coupler, which can be a photonic lantern, configured to combine light beams into a common light beam; a sensor configured to measure at least one characteristic of the common light beam; and a controller configured to modulate optical parameters of the individual, respective light beams to set one or more spatial modes of the common light beam. Actively controlled and modulated devices can be used to maintain a stable, diffraction-limited beam for use in an amplification, communications, imaging, laser radar, switching, or laser material processing system. Embodiments can also be used to maintain a fundamental or other spatial mode in an optical fiber even while scaling to kilowatt power.

Electro-Optic beam controller and method

Herein is provided a fiber length including a doped fiber core extending over the fiber length. First and second cladding regions radially surround the core. At least one pump light input site is arranged to accept input pump light into the first cladding region. A low-absorption length over which the first cladding region has a first cross-sectional geometry produces a first level of absorption of input pump light from the first cladding region to the core, extending from a pump light input site for an extent over which the doped core can absorb at least about 10% of input pump light from the first cladding region. A high-absorption section over which the first cladding region has a second cross-sectional geometry produces a second level of absorption of input pump light from the first cladding region to the core, greater than the first level of absorption of input pump light.

A method of processing a work material using a laser can include directing a laser beam of optical energy from a laser to a work material; processing the work material with the laser beam of optical energy in accordance with at least one processing parameter to modify the work material, the processing of the work material having associated therewith an optical signature; sensing a characteristic of the optical signature; and varying the at least one processing parameter responsive to the sensing of the characteristic of the optical signature. Other related methods are disclosed, as are laser processing systems, which systems can be used to practice the methods.

Methods and systems for laser processing of materials

A WDM fiber optic communication system is operative to transmit WDM signals between multiple nodes. Each node has a booster EDFA, and in-band and out-of-band supervisory channels monitoring the integrity of a link by generating and detecting respective in-band and out-of-band control signals. The booster EDFA receives the multiplexed WDM and IB signals and generates an output signal carried by fibers between the nodes. The booster EDFA switches from an automatic gain control regime upon detecting of at least one of the IB and OB control signals to an automatic power control regime upon loss of both IB and OB control signals. The output signal of the EDFA in the AGC regime has a high power sufficient for transmitting the WDM and IB signals, and has a low power in the APC regime sufficient for transmitting only the IB control signal.

Growing community of inventors

Northbridge, MA, United States of America

Peter Colin Reeves-Hall