Fiber Bragg gratings made with a phase mask and 800-nm femtosecond radiation

Abstract

High-quality retroreflecting fiber Bragg gratings were written in standard Ge-doped telecom fiber (Corning SMF-28) after a few minutes exposure with pulsed 800-nm, 120-fs laser radiation by use of a deep-etch silica zero-order nulled phase mask optimized for 800 nm. Induced index modulations of 1.9 x 10(-3) were achieved with peak power intensities of 1.2 x 10(13) W/cm2 without any fiber sensitization. The fiber gratings are stable and did not erase after 2 weeks at 300 degrees C. The primary mechanism of induced index change results from a structural modification to the fiber core.

Tomographic measurement of femtosecond-laser induced stress changes in optical fibers

“…3 Recently, femtosecond laser pulses have been used to write three-dimensional waveguide structures in a variety of bulk glass samples. 4,5 Furthermore, long period gratings 6 as well as fiber Bragg gratings 7 have been realized by modification of the core index in germanosilicate fibers. For waveguide as well as grating formation, intensity and power of the femtosecond pulses are in general below their corresponding threshold values for optical breakdown and self-focusing.…”

Point-by-point inscription of fiber Bragg gratings into birefringent optical fiber through protective acrylate coating by Ti:Sa femtosecond laser

“…Подобные изображения решеток, записан-ных ArF и KrF эксимерными лазерами методом фазовой маски, ранее были получены авторами в работах [16,17]. Также данное изображение схоже с решеткой, индуцированной излучением Ti:Sa ИК фемтосе-кундного лазера методом фазовой маски [18]. Период решетки составляет примерно 1,07 мкм, что соот-ветствует заданному отношению скорости протягивания ОВ к частоте импульсов.…”

High order Bragg gratings for short wavelengths operation

“…The saturation effect of the induced index is also considered. The experiment is carried out in Ge-doped fiber under the exposure of UV femtosecond radiation, which is associated to multiphoton absorption process in the mechanism for photoinduced index change [7], ensuring the effectivity and stability of high order gratings in short wavelength range.…”