NANO ENGINEERED OPTICAL FIBERS AND APPLICATIONS

OUTLINE Introduction to photonic crystal fibers. Nano engineered optical fiber. Design and applications of nano engineered optical fiber.

OPTICAL FIBER A transparent “waveguide” (usually doped silica glass) designed to transmit light. Coating Core Cladding

PHOTONIC CRYSTAL FIBERS(PCF)  They are optical fibers that employ a microstructured arrangement of low-index material in a background material of higher refractive index.  The background material is undoped silica.  The low index region is typically provided by air voids running along the length of the fiber.

TYPES OF PCF PCFs come in two forms: High index guiding fibers based on the Modified Total Internal Reflection (M-TIR) principle Low index guiding fibers based on the Photonic Band Gap (PBG) effect.

ADVANTAGES PCF with high-index core is more flexible than conventional fiber: - Possible to make very large core area to send high power - Possible to make core very small compared to conventional fibers. Designer wavelengths possible. Air-guiding PCF (hollow core of fiber): - Possible to send high power

CHALLENGES Difficult to fabricate. Less attractive for large scale and cost sensitive applications

NANO ENGINEERED OPTICAL FIBER  Uses the nanostructures technology  Manufactured using Standard Outside Vapor Deposition(OVD) process.

NANO ENGINEERED GLASS FIBER Figure 1:(Scanning Electron Microscopy ) SEM picture of a fiber with nano- engineered cladding.

 Consists of 20 µm diameter void free silica core.  Voids are non periodically distributed in the cladding.  Voids are filled with gas.  Cross section of the voids are circular.  Void fill fraction can be designed to be between 1 to 10 percent.

ADVANTAGES OF NANO ENGINEERED GLASS FIBERS  Refractive index of nano-engineered glass has much stronger wavelength dependence than that of fluorine doped glass.

 Large negative index changes can be made with nanometer sized features.  Scattering property of glass having nanometer sized voids has strong wavelength dependence.

NANO ENGINEERED FIBER DESIGNS AND APPLICATIONS Figure2:Germania doped core and nano -engineered ring in the cladding DESIGN:1

BENDING PERFOMANCE

 Typical bending loss at 5mm radius is.03 dB/turn at 1550nm wavelength.  Suitable for making bend insensitive fiber for FTTH applications.  Suitable for large scale production.

Figure 3:pure silica core and a nano engineered cladding  Does not require any conventional dopants in the core and the cladding regions.  Both single mode and multimode fibers can be designed. DESIGN:2

 ATTENUATION SPECTRUM  Fiber is single moded over the complete measured wavelength range of 600 to 1700 nm

FEATURES OF NANO ENGINEERED OPTICAL FIBER  Ultra –low bending loss.  Suitable for large scale production.  Easy to manufacture.  By changing the design it can be used for different applications.

CONCLUSION  NanoStructures technology is an engineering breakthrough technology that adds new dimension to the conventional fiber design space.  The excellent bending performance of new nano- engineered fibers is used for FTTH applications.  The new technology is compatible with the OVD process and suitable for large scale production.

REFERENCES  M.-J. Li, P. Tandon, D. Bookbinder, D. Nolan, S. Bickham, M. McDermott, R. Desorcie, J. Englebert, S.Logunov, V. Kozlov, and J. West” Nano Engineered Optical Fibers and Applications”,IEEE OSA/OFC/NFOEC  M.-J. Li, P. Tandon, D. C. Bookbinder, S. R. Bickham, M. A. McDermott, R. B. Desorcie, D. A. Nolan, J. J Johnson, K. A. Lewis, and J. J.Englebert, “Ultra-low Bending Loss Single-Mode Fiber for FTTH”, OFCNFOEC2008, paper PDP10, San Diego, California, February 24,2008.  M.-J. Li, P. Tandon, D. C. Bookbinder, S. R. Bickham, M. A. McDermott, R. B. Desorcie, D. A. Nolan, J. J Johnson, K. A.Lewis, and J. J. Englebert, “Ultra-low Bending Loss Single-Mode Fiber for FTTH”, J. Lightwave Technol. Vol. 27, no. 3, pp , 2009.