Bandpass Filter Composed of Long-Period Fiber Gratings with Absorptive Core Mode Blocker and Its Temperature Characteristics

Shunpei SUZUKI  Hisashi ITO  Hajime SAKATA  

C - Abstracts of IEICE TRANSACTIONS on Electronics (Japanese Edition)   Vol.J91-C   No.6   pp.325-331
Publication Date: 2008/06/01
Online ISSN: 1881-0217
Print ISSN: 1345-2827
Type of Manuscript: PAPER
long-period fiber grating,  bandpass filter,  core mode blocker,  temperature sensing,  

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We present a fiber bandpass filter composed of two similar long-period fiber gratings (LPFGs) and an absorptive core-mode blocker that is formed between the cores of the two LPFGs. The transmission spectrum of the bandpass filter exhibited the side-mode suppression ratio of 13 dB by designing the radius and absorption strength of the core-mode blocker. By increasing the temperature, the center wavelength of the filter shifted toward the shorter wavelength side by the thermal sensitivity of -0.51 nm/. Filter wavelength shift was converted to the transmitted power change by using a 1.5 µm-band light-emitting diode as an input light source.