Semiconductor saturable absorber mirror passively Q-switched 2.97 μm fluoride fiber laser

Abstract

A diode-cladding-pumped mid-infrared passively Q-switched Ho 3+-doped fluoride fiber laser using a reverse designed broad band semiconductor saturable mirror (SESAM) was demonstrated. Nonlinear reflectivity of the SESAM was measured using an in-house Yb 3+-doped mode-locked fiber laser at 1062 nm. Stable pulse train was produced at a slope efficient of 12.1% with respect to the launched pump power. Maximum pulse energy of 6.65 µJ with a pulse width of 1.68 µs and signal to noise ratio (SNR) of ~50 dB was achieved at a repetition rate of 47.6 kHz and center wavelength of 2.971 µm. To the best of our knowledge, this is the first 3 μm region SESAM based Q-switched fiber laser with the highest average power and pulse energy, as well as the longest wavelength from mid-infrared passively Q-switched fluoride fiber lasers.

Watt-level passively Q-switched heavily Er3+-doped ZBLAN fiber laser with a semiconductor saturable absorber mirror

“…12. The threshold of launched pump power for CW operation was 0.52 W. The laser started to work in Q-switching when the launched pump power was 0.59 W, whereas the pulse trains were unstable.…”

“…5 is also named red-shift, which is very common in lasers without wavelength selecting elements in the cavity when the pump power increasing2, due to the fact that the more the pump power, the higher the temperature of the active medium, and the lower the initial Stark level of upper laser level12. The stability of output spectrum would be improved greatly and the bandwidth could be narrowed significantly by using a bulk grating or a fiber Bragg grating in the laser cavity2.…”

“…According to the passively switched theory with a SESAM, we could estimate the length of active fiber with which the laser operated in pure Q-switched regime at watt-level without mode-locking using the following condition1227:…”

635-nm Visible Pr3+-Doped ZBLAN Fiber Lasers Q-Switched by Topological Insulators SAs

“…Compared to active pulsed lasers, passive ones with saturable absorbers (SAs) possess the attractive advantages of compactness, simplicity, and flexibility in design. To date, various SAs, such as semiconducting saturable absorber mirror (SESAM) [1], [2], single-walled carbon nanotube (SWCNT) [3], [4], and two-dimensional (2D) materials (e.g. graphene, topological insulators (TIs)) [5]- [17] have been used to realize pulsed operation in lasers.…”

Submicrosecond Q-Switching Er-Doped All-Fiber Ring Laser Based on Black Phosphorus

“…Among them, passive Q-switching technology based on saturable absorber (SA) has made remarkable progress in view of compact, low cost, flexible, and so on. Since the Nd:glass (the first generation of SA) was successfully used for pulse generation in 1966 [7], a wide variety of SAs have been intensively developed, such as Semiconductor Saturable Absorption Mirrors (SESAMs) [8,9], Carbon Nanotubes (CNTs) [10][11][12][13], graphene [14][15][16][17][18], Topological Insulator (TI) [19,20], and Transition Metal Dichalcogenides (TMDs) [21][22][23][24]. The SESAMs are utilized in most of commercially available laser systems for high flexibility and stability.…”