Ultrafast laser written active devices

Abstract

Direct-write optical waveguide device fabrication is probably the most widely studied application of femtosecond laser micromachining in transparent dielectrics at the present time. Devices such as buried waveguides, power splitters, couplers, gratings, optical amplifiers and laser oscillators have all been demonstrated. This paper reviews the application of the femtosecond laser direct-write technique to the fabrication of active waveguide devices in bulk glass materials.White light diffraction from waveguide Bragg gratings fabricated in doped phosphate glass using the femtosecond laser direct-write technique. Such a waveguide Bragg grating was instrumental to the first demonstration of a monolithic waveguide laser using this technique.

Fabricating waveguide Bragg gratings (WBGs) in bulk materials using ultrashort laser pulses

“…True monolithic WGL operation was subsequently demonstrated by Marshall et al in a DFB configuration [6,30]. In this case, a 20-mm-long Er:Yb codoped phosphate glass with a 500 nm period WBG lased when pumped with 710 mW at 976 nm.…”

“…In the past 20 years, many research articles have been published in the field, either giving insight into the light-material interactions underlying the technique or demonstrating one of the multitudes of photonic components that have been fabricated. The reader is directed to these selected review articles for an overview [4][5][6][7][8][9][10][11].…”

Femtosecond pulse written fiber gratings: a new avenue to integrated fiber technology

“…Thus, by translating the sample, the 3-dimensional writing of waveguides is possible [27,28]. This allowed for the laser inscription of a large variety of tightly packed new integrated optical elements [29,30]; especially in active [31] and nonlinear crystals and glasses [32].…”

“…Commonly used for LPG-inscription [60][61][62][63][64][65], this approach has also been successfully employed for Bragg reflecting waveguides in bulk material [39,[66][67][68], especially in combination with high repetition rate lasers that increase fabrication speed significantly [66,68]. (Ams et al reviewed distributed feedback lasers based on such Bragg waveguides extensively in [31]). For FBG inscription, however, the single shotapproach seems to prevail.…”

“…In contrast, direct ultrafast laser inscription relies on nonlinear absorption and also works in nonphotosensitive glasses and crystals [31,32]. Thus, grating inscription in almost any optical fiber is possible [70]: FBGs could be realized in heavily doped phosphate glass fibers [97] and in highly nonlinear bismuth oxide fibers [98] as well as ZBLAN fibers [99].…”