First order fiber Bragg grating inscription with femtosecond laser and reflection wavelengths from visible to infrared

Abstract

strong gratings can be achieved without the need of hydrogen loading and with short inscription times arounc setu in Fioure 1. These oratinos are written in sinole mode fibers without hydrooen loadin . It shows that iure 2 shows ratin transmission s )ectra in the Erbium and Thulium am li cation band made with the non-photosensitive fibers without hydroren loadin ultraviolet emtosecond laser as shown in Fi ure 1. It allows the realization o ber Bra°ratin arrays it For fiber Bra..:ratint inscription, a phase -mask interferometer setu D was chosen which is driven by ai .aMilMeWtItitMIDVI telII nd colour center ormation a''ect the transmission at the fiber Bra oratino re ection wavelen th tenter ormation is mainly res onsible or hotosensitivity, one has to take into account that )hotodarkenino ations, .ratina re `ectin. in the visible and near in rared s Dectral re :ion are o interest.` ssumin. that colour Ytterbium amplification bands at 2 .m, 1.55 tin and 1.06 .m can be achieved. Especially or biophotonic appli need of photosensitivity and or germanium doping. It is shown that fiber Bragg gratings in the Thulium, Erbium and laser driven two -beam inter erometry allows wavelen th versatility o the inscri 3tion wavelength without the Fiber Bra ratin s are key com onents or )oint ber sensino, laser technolo y and communications. Femtosec i .1M\M 11:COTaKe M [O71 e words: Femtosecond Lasers, ber Brame,, oratinos, hase mask inter erometer, VI n'A -.m, s-., nl1 -.r in s r r.-11 siz-, r m 11 nm without the need or ermanium do in or hydro en loadin . The ratin in the visible re ion is remarkabl. interferometer (O = 90 degree) (compare Hi1P). Using this condition, one gets )\Braa__min 1160 nm for and laser ex 3osure. This allows to taret first order Bra oratino re ections rom 2000 nm down to 660 nn We re ort on the inscri tion o fiber Bra°ratin s with two -beam inter erometry and dee 3 ultraviolet emtosec I emtosecon. Laser an. Re ` ection Wave en ' t s From Visi erst r er Fa er Bra IP IMP ratan ' Inscri tion Wit he 3hysical limit o the shortest re ection wavelen th is defined by the standin wave condition o the fiber. For direct phase mask inscription O is defined by sin O = A "'" (APM is the phase mask period)eld index, ñinscr is the inscri tion wavelength, and 0 is the incident anale o the beams relative to the tare Here ABragg is the Bragg grating re ection wavelength, m is the Bragg re ection order, neff is the e' ective mode he fiber Bragg grating re ection wavelength )'Bragg in a single mode fiber is described by