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University Park, MD, United States

Gattass R.R.,U.S. Navy | Kung F.H.,University Research Foundation | Busse L.E.,U.S. Navy | Shaw L.B.,U.S. Navy | Sanghera J.S.,U.S. Navy
Optical Engineering | Year: 2014

The bending loss is a critical parameter for packaging, representing a limiting parameter in the minimization of fiber-based devices. For applications in the midinfrared spectral band, chalcogenide glass optical fibers are one of the few alternatives for high-power beam delivery. We present experimental results for the bending loss of a sulfide-based multimode chalcogenide fiber for a broad range of infrared wavelengths as well demonstrating 5.8 W power handling for a 6.25-mm radius bend. © The Authors.

Thapa R.,Sotera Defense Solutions | Gattass R.R.,U.S. Navy | Nguyen V.,U.S. Navy | Chin G.,University Research Foundation | And 4 more authors.
Optics Letters | Year: 2015

We demonstrate a low-loss, repeatable, and robust splice between single-mode silica fiber and single-mode chalcogenide (CHG) fiber. These splices are particularly difficult to create because of the significant difference in the two fibers' glass transition temperatures (∼1000°C) as well as the large difference in the coefficients of thermal expansion between the fibers (∼20 × 10-6 /°C). With 90% light coupled through the silica-CHG fiber splice, predominantly in the fundamental circular-symmetric mode, into the core of the CHG fiber and with 0.5 dB of splice loss measured around the wavelength of 2.5 μm, after correcting only for the Fresnel loss, the silica-CHG splice offers excellent beam quality and coupling efficiency. The tensile strength of the splice is greater than 12 kpsi, and the laser damage threshold is greater than 2 W (CW) and was limited by the available laser pump power. We also utilized this splicing technique to demonstrate 2 to 4.5 μm ultrabroadband supercontinuum generation in a monolithic all-fiber system comprising a CHG fiber and a high peak power 2 μm pulsed Raman-shifted thulium fiber laser. This is a major development toward compact form factor commercial applications of soft-glass mid-IR fibers. © 2015 Optical Society of America.

Bayya S.,U.S. Navy | Villalobos G.,U.S. Navy | Kim W.,U.S. Navy | Sanghera J.,U.S. Navy | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

There are several military or commercial systems operating in very harsh environments that require rugged windows. On some of these systems, windows become the single point of failure. These applications include sensor or imaging systems, high-energy laser weapons systems, submarine photonic masts, IR countermeasures and missiles. Based on the sea or land or air based platforms the window or dome on these systems must withstand wave slap, underwater or ground based explosions, or survive flight through heavy rain and sand storms while maintaining good optical transmission in the desired wavelength range. Some of these applications still use softer ZnS or fused silica windows because of lack of availability of rugged materials in shapes or sizes required. Sapphire, ALON and spinel are very rugged materials with significantly higher strengths compared to ZnS and fused silica. There have been recent developments in spinel, ALON and sapphire materials to fabricate in large sizes and conformal shapes. We have been developing spinel ceramics for several of these applications. We are also developing β-SiC as a transparent window material as it has higher hardness, strength, and toughness than sapphire, ALON and spinel. This paper gives a summary of our recent findings. © 2014 SPIE.

Sanghera J.S.,U.S. Navy | Shaw L.B.,U.S. Navy | Pureza P.,U.S. Navy | Nguyen V.Q.,U.S. Navy | And 5 more authors.
International Journal of Applied Glass Science | Year: 2010

We demonstrate that the chalcogenide glasses possess large nonlinearities that can enable compact Raman amplifiers as well as fiber lasers and amplifiers in the mid-IR. These high nonlinearities also allow efficient supercontinuum generation, which is useful for broadband sources in the near and mid-IR. These materials can also be poled to induce an effective χ(2), opening up the potential of waveguide parametric amplifiers and sources. The Brillouin gain coefficients are relatively large and enable the demonstration of slow light in small core fibers. Results lead to a figure of merit that is about 140 times larger, or a theoretical gain about 45 times larger, than the best silica-based fiber configurations reported to date. © 2010 The American Ceramic Society and Wiley Periodicals, Inc. No claim to U.S. government works.

News Article | February 27, 2013
Site: www.techworld.com

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