In this paper we present an effective method of pulse distortion pre-compensation in saturated high-power fiber amplifiers by arbitrarily shaping the input pulse. We derive a simple expression which allows us to generate user-defined pulse shapes at the output of the amplifier chain consisting of more than one stage. The numerical results were verified experimentally using a diode-seeded all-fiber two-stage master oscillator–power amplifier (MOPA) source based on Er³⁺/Yb³⁺-doped double-clad fiber. Several examples of obtained output shapes are presented, including high-energy 100-ns-long rectangular pulses.

We report the design and characteristics of a simple and compact mode-locked Er-doped fiber laser and its application to broadband cavity-enhanced spectroscopy. The graphene mode-locked polarization maintaining oscillator consumes less than 5 W of power. It is thermally stabilized, enclosed in a 3D printed box, and equipped with three actuators that control the repetition rate: fast and slow fiber stretchers, and metal-coated fiber section. This allows wide tuning of the repetition rate and its stabilization to an external reference source. The applicability of the laser to molecular spectroscopy is demonstrated by detecting CO₂ in air using continuous-filtering Vernier spectroscopy with absorption sensitivity of 5.5 × 10⁻⁸ cm⁻¹ in 50 ms.

In this paper we present a novel configuration of an NPR mode-locked Er-doped laser. This new optical setup uses voltage controlled LC cells to replace standard retarders (quarter-and half-waveplates) inside the laser cavity. Using this novel, mechanical-adjustment-free setup a mode-locking was obtained with sub-500 fs pulse duration and an average power exceeding 40 mW. Presented results show that using simple LC cells, an optical layout of an NPR mode-locked laser can be greatly simplified.

The multichannel WDM (Wavelength Division Multiplexing) technique inspired the concept of vibration measurements for many points of a vibrating object. The N-independent WDM separated 15XX nm fibre coupled laser diodes (used for optical fibre telecommunication) form coherent system of sources for multipoint measurement of vibrations according to the rule one wavelength - one point. The scattered light from the object coupled into the fibre, filtered coherently, after special signal processing, allows analysing amplitudes and phases of many vibrating points in real time. Some experiments and results of such system will be demonstrated.

Laser-Doppler vibrometry (LDV) is widely used in the assessment of auditory ossicles displacement. The method has been used in fundamental research on middle ear mechanics,^{1 – 6} optimization of surgical procedures^{2,7 – 15} such as intraoperative qualification for implantable middle ear hearing devices,^2,16,17 and intraoperative evaluation of hearing improvement during ossiculoplasty.^{18 – 26} Vibrometric studies have also been conducted for potential applications in the clinical diagnosis of hearing loss.^{27 – 30} The LDV method enables non-contact measurement in a wide frequency band at a precisely determined point and is a gold standard in cadaver tests. However, despite numerous in vivo studies, it is not routinely used in clinical settings.