We believe that the experimental results are very useful for applications to fiber optic sensors, optical switch filters, etc. Acknowledgements This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2012R1A1A2000999). References 1. Vengsarkar AM, Lemaire PJ, Judkins JB, Bhatia V, Erdogan T, Sipe JE: Long-period fiber gratings as band-rejection filters. J Lightwave Technol 1996, 14:58.CrossRef 2. Han YG, Lee SB, Kim CS, Jin U, Kang U, Paek C, Chung Y: Simultaneous measurement of temperature and strain using dual long-period fiber gratings Fedratinib with controlled temperature

and strain sensitivity. Opt Express 2003, 11:476.CrossRef 3. James SW, Tatam RP: Optical fibre long-period grating sensors: characteristics and application. Meas Sci Technol 2003, 14:49.CrossRef 4. Lin CY, Wang LA: Corrugated long-period fiber gratings as stran, torsion, and bending sensor. J Lightwave Technol 2001, 19:1159.CrossRef 5. Han YG, Lee SB: Discrimination of strain and temperature Selleckchem Sirolimus sensitivities based on temperature dependence

of birefringence in long-period fiber gratings. Jpn J Appl Phys 2005, 44:3971.CrossRef 6. Pham VH, Bui H, Hoang LH, Nguyen TV, Nguyen TA, Pham TS, Ngo QM: Nano-porous silicon microcavity sensors for determination of organic fuel mixtures. J Opt Soc Korea 2013, 17:423.CrossRef 7. Schwettmann FN, Dexter RJ, Cole DF: Etch rate characterization of boron-implanted thermally grown SiO 2 . J Electrochem Soc 1973, 120:1566.CrossRef Competing interests The authors declare that they have no competing interests. Authors’ contributions O-JK and MS participated in the experimental fabrication. Y-GH wrote and corrected the manuscript and conceived and supervised the study. All authors read and approved the final manuscript.”
“Background Vertical-cavity semiconductor optical amplifiers (VCSOAs) at 1.3 μm are key photonic components in optical communication systems [1–4]. Dilute nitride III-V alloy semiconductors and in particular GaInNAs/GaAs quantum well (QW)-based

VCSOAs were originally proposed as replacements for GaInAsP/InP QWs due to its reduced temperature sensitivity and inherent polarization insensitivity [5, 6]. In addition, their growth on GaAs and their integrability with GaAs/Al(Ga)As distributed Bragg reflectors (DBRs) allowed second them to be considered as the active click here region in 1.3-μm vertical-cavity devices. In this article, a novel VCSOA based on the hot electron light emission and lasing in semiconductor heterostructure (HELLISH) as an alternative to conventional VCSOAs is investigated [7]. Spontaneous emission of ultra bright HELLISH has been previously reported and demonstrated by us [8, 9]. The simple bar HELLISH-VCSOA [10] and Top-Hat HELLISH-VCSOA [11] structures with GaInNAs/GaAs quantum wells in the active region are designed to operate in the 1.3-μm wavelength region.