## 1 Introduction  
In recent years, laser sources operating around 3 \(\upmu\)m have been widely studied for using in spectroscopy, differential absorption lidar, remote sensing, and laser surgery because their wavelength coincides with the strong absorption spectral region of the water, vapor and biological tissues [1]. Optical parametric oscillation, stimulated raman scattering, and semiconductor technology can be used to access the mentioned laser radiations [2, 3]. In terms of the cavity simplicity and the laser-output beam quality, Er\({}^{3+}\) doped solid-state lasers at \(\sim\)3 \(\upmu\)m are of great interest and have been widely studied utilizing the developed InGaAs laser diode emitting around 980 nm as pump sources [4, 5, 6, 7]. Conventionally, lifetime of the upper laser level for the Er 3-\(\upmu\)m laser transition is less than that of the terminal one. High Er\({}^{3+}\) ions doped concentration is highly desired to prevent the self-terminating effect of the transition of \({}^{4}\)I\({}_{11/\rightarrow}\)\({}^{4}\)I\({}_{13/2}\) and to depopulate the level of \({}^{4}\)I\({}_{13/2}\) state with the concentration related up-conversion process. In YAG and YSGG hosts, for example, the optimized doping levels for efficient Er 3-\(\upmu\)m laser operation are as high as 50 at.% and 30 at.% [4]. In order to obtain a higher laser output power with such gain medium, evaluation of the thermal effect and the laser efficiency is necessary [5, 6]. Therefore, the recently developed Er:Y\({}_{2}\)O\({}_{3}\) ceramics with a relatively lower concentration for efficient 3-\(\upmu\)m laser operation have gained considerable attention because of their lower phonon energy, larger cation density, and higher thermal conductivity. The transmission spectrum of the Er:Y\({}_{2}\)O\({}_{3}\) ceramics and the transmission level at the lasing wavelength have already been reported in ref. [8]. Recent studies have shown that the Er:Y\({}_{2}\)O\({}_{3}\) ceramic is a promising laser gain medium for high power 3-\(\upmu\)m continuous-wave (CW) and nanosecond pulsed operations [7, 8, 9]. Large amounts of energies can be released by ultrafast lasers at a short timescale, and hence this type of lasers are of great interest for some practical applications. Picosecond lasers at 3 \(\upmu\)m can be used in minimally invasive devices for laser microsurgery [10; 11]. Laser pulses generated from continuous-wave mode locking (CWML) have advantages of high pulse stability and low noise. While lasers in the mode of Q-switched and mode locked (QML) operation can achieve much higher pulse energy [12]. In the past decades, the operation of QML with 3-\(\upmu\)m solid-state lasers is conducted mostly based on Er:YAG, and its applications in microsurgery have been studied using flash-lamp-pumped scheme. Normally, the Q-switched envelop has the repetition frequency of 1 Hz\(\sim\)2 Hz due to the inherent severe thermal effect [13; 14]. In the wavelength region of 3-\(\upmu\)m, Er\({}^{3+}\) doped thermally advanced sesquioxides should be an alternative option for short pulses laser generation with high power and repetition rate. In addition, the relatively large emission cross sections should enable a reduced threshold for picosecond pulse generation in mode locked mode of operation [15; 16]. We report in this paper the realization of stable Q-switched and mode-locked operation of an 2.7 \(\upmu\)m Er:Y\({}_{2}\)O\({}_{3}\) ceramic laser pumped by a high brightness, linearly polarized Yb-fiber source at 976 nm and using a semiconductor saturable mirror. The Er:Y\({}_{2}\)O\({}_{3}\) ceramic sample is home-developed and over 92 mW of average output power is generated. The mode-locked pulses embedded inside Q-switched envelopes of \(\sim\)1.2 \(\upmu\)s width have a modulation depth of 100% and repetition frequency of 130 MHz. Repetition rates of the Q-switched pulse envelope are tunable from 5.1 kHz to 29 kHz with the width varying from 2.7 \(\upmu\)s to 1.2 \(\upmu\)s via varying the incident pump power.