Bandpass transmission filters based on phase shifted fiber Bragg gratings in microstructured polymer optical fibers

Abstract

In this contribution we report on the fabrication of novel bandpass transmission filters based on PS-FBGs in microstructured polymer fibers at telecom wavelengths. The phase mask technique is employed to fabricate several superimposed gratings with slight different periods in order to form Moiré structures with a single or various π phase shifts along the device. Simulations and experimental results are included in order to demonstrate very narrowband transmission filters. Experimental characterization under strain and temperature variations is provided in a non-annealed fiber and time stability of the fabricated devices has been also measured under different pre-strain conditions.

Fabrication and Characterization of Bragg Grating in CYTOP POF at 600-nm Wavelength

“…To the best of our knowledge, no reports are published in the literature on the strain sensitivity of FBGs in POF at 600 nm region. The strain sensitivity of PMMA mPOF Bragg grating at 850 nm wavelength is about 0.711 pm/µε [16] and at 1560 nm wavelength is around 1.58 pm/µε [17]. Nevertheless, this lower sensitivity obtained in 600 nm region is consistent with the FBG wavelength shift with strain that presents an upward trend with respect to the Bragg wavelength increase, since the wavelength shift (Δλ) is defined as Eq.…”

Latest Achievements in Polymer Optical Fiber Gratings: Fabrication and Applications

“…Recently, a novel bandpass transmission filter based on PS FBG at telecom wavelength [105] was obtained using the Moiré method by 325 nm Kimmon laser system exposure for about 20 mins, as shown in Figure 5. A Moiré structure is formed by superimposing two gratings of equal amplitude but with slightly different periods.…”

“…Phase-shifted (PS) FBG fabricated by 325 nm irradiation: (a) uniform FBG (first fabrication step), (b) PS FBG (Moiré structure based on two overlapped uniform gratings); image adapted from[105].…”

Advances on Polymer Optical Fiber Gratings Using a KrF Pulsed Laser System Operating at 248 nm

“…All the POFs were pre-annealed on the results presented. Regarding the different types of POFBGs inscribed with the 325 nm laser, a phase-shifted POFBG (PS-POFBG) was proposed in [46], with inscription times lower than 14 min. There is another report of PS-POFBG, where a weak PS-POFBG is presented in the 1550 nm region, but it lacks sharpness in the notch region.…”