Comparative study of Er3+-doped Ga-Ge-Sb-S thin films fabricated by sputtering and pulsed laser deposition

Solution-processed Er3+-Doped GeS2 chalcogenide glass films with NIR photoluminescence towards functional flexibility and integration

Rare-earth doped chalcogenide films are major components in flexible and integrated photonic and optoelectronic devices for modern communication systems, metrology, and optical sensing. However, it is still challenging to develop a high concentration of rare-earth doping chalcogenide film with a smooth surface to realize efficient photoluminescence (PL). Here, we demonstrate that Er3+-doped GeS2 films are prepared by spin-coating based on a two-step dissolution process. Such a two-step process provides the high solubility of Er3+ in GeS2 films and exhibits efficient emission at ∼1.5 µm crossing the telecommunication C-band. The highest PL emission intensity is obtained in GeS2 films doped with 1.4 mol% of Er3+, and this PL in GeS2 films is reported for the first time. We propose adjustments of annealing parameters for improving the PL characteristics in such materials. Through the control precision of the heating rate and annealing temperature, the smooth surface of GeS2 films enables efficient photo-luminescence. This two-step dissolution-based strategy would pave a new path to design luminescent chalcogenide films for application in flexible and integrated optoelectronics and photonics.

Mid-infrared laser performance of Ce3+-doped selenide glass

An extensive study of a novel room-temperature mid-infrared Ce³⁺-doped Ge₂₀Sb₁₀Ga₅Se₆₅ glass laser is reported. An influence of output-coupler transmission on laser efficiency and emission spectra is investigated. Pumped by a pulsed Fe:ZnSe laser at 4.1 µm, a maximum output energy of 35 mJ is demonstrated at 5.2 µm, with a laser threshold of about 60 mJ and a slope efficiency of 21%. The tuning range of a mid-infrared Ce:glass laser is reported for the first time: with an intracavity prism, the laser is continuously tunable in the spectral range of 4.5-5.6 µm. The internal losses are determined to be below 9% per roundtrip.

Efficient generation of triangular optical pulses in an erbium-doped chalcogenide fiber amplifier by exploiting the time transformation technique

The time transformation (TT) technique is used to study the nonlinear pulse reshaping towards triangular pulse (TP) generation by efficiently optimizing the pulse parameters in an erbium-doped chalcogenide fiber amplifier (EDCFA), for the first time, to the best of our knowledge. The effects of input chirp parameter, optical gain, and dipole relaxation time are also depicted in the context of TP generation. The results obtained from the TT approach when compared with that from the nonlinear Schrodinger equation show excellent agreement. The study also reveals that spectral pulse doubling can be achieved at a shorter length when a pre-chirped Gaussian pulse is propagated through the proposed EDCFA.

Co-sputtered Pr3+-doped Ga-Ge-Sb-Se active waveguides for mid-infrared operation

This work reports on the properties of luminescent waveguides based on quaternary Ga-Ge-Sb-Se amorphous thin films doped with praseodymium. The waveguides were fabricated via magnetron co-sputtering, followed by inductively coupled plasma reactive ion etching. The initial thin film thickness and optical properties were assessed and the spectroscopic properties of the waveguides were measured. The measurements show promising results-it is possible to obtain mid-infrared fluorescence at 2.5 and 4.5 µm by injecting near-infrared light at 1.5 µm as the pump beam. By comparing waveguides with various praseodymium concentrations, the optimal doping content for maximum fluorescence intensity was identified to be close to 4100 ppmw. Finally, correlation between the intensity of mid-infrared emission and the width/length of the waveguide is shown.