Transverse Fiber Lasers

Technology #12066

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Fig. 1. Photonic band gap fiber laser. The fiber laser emits light in the transverse direction (propagation and polarization vectors shown as solid arrows and dashed lines, respectively) having a dipole-like wave front from an extended length of the fiber.Fig. 2. Structure of the fiber laser cavity. (a), Cross-sectional SEM micrographs of the PBG multilayer structure at various magnifications. The PEI in the cladding and the layers appears black, and the As2S3 layers white. The PEI and As2S3 layers are 89 nm and 59 nm thick (except for the first and last As2S3 layers which are 29.5 nm thick; the first layer is not visible). The top left inset shows a cross-sectional fluorescence micrograph of the full cross-section of a PBG fiber with an R590 organic dye in the core and enveloped by a thick PEI protective cladding. (b), Projected band structure of a one dimensional photonic crystal consisting of alternating layers of As2S3 and PEI. Transverse-electric (TE) and transverse-magnetic (TM) propagating modes are in dark and light blue, respectively; evanescent modes are in white. Light incident normally to the structure (k=0) and axially propagating modes through the hollow core are shown as regions A and B, respectively. (c), Measured reflection band gap centered around 620nm (see ‘Optical characterization’ in methods) in black; fluorescence spectrum of LDS698 (500 ppm concentration) in red; and calculated dye-in-cavity emission obtained by multiplying the last two, dashed line.
Categories
Inventors
Professor John Joannopoulos
The Institute for Soldier Nanotechnologies, MIT, MIT
External Link (www.rle.mit.edu)
Professor Yoel Fink
The Institute for Soldier Nanotechnologies, MIT
External Link (dmse.mit.edu)
Ofer Shapira
Research Laboratory of Electronics, MIT
Ken Kuriki
Research Laboratory of Electronics, MIT
Nicholas Orf
Research Laboratory of Electronics, MIT
Alexander Stolyarov
Lincoln Laboratory, MIT
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Surface-emitting fiber laser

US Patent 7,970,022
Publications
Surface-emitting fiber lasers
Optical Express, Vol. 14, Issue 9, pp. 3929-3935

Applications

This invention has interesting applications in medical imaging, sensing, bio-sensing, textile fabric displays and security systems.

Problem Addressed

Applications of existing fibers are limited since they emit radiation only along the fiber axis. There is a need for a new fiber technology that emits radiation along its surface to enable new applications.

Technology

The invention is a fiber that exhibits laser emission that is radially directed from its circumferential surface. The cylindrical fiber-cavity structure consists of a hollow-core multilayer photonic band gap fiber, and an organic dye gain medium that is introduced into the core. The complete photonic band gap provides the longitudinal confinement of the higher-frequency optical pump and at the same allows light to travel along the fiber at steep angles (with respect to the fiber axis).  Hence, a stable, axially symmetric ring-like radiation from the extended surface is produced.

Advantages

  • Offers unique control over the direction and polarization of the lasing wave front
  • Inherently wavelength scalable