Design of mid-IR microstructured fiber light source based on dysprosium doped chalcogenide glass
The paper deals with the design of a medium infrared (Mid-IR) light source based on a microstructured fiber made of dysprosium doped chalcogenide glass, Dy3+:Ga5Ge20Sb10S65. It is constituted by the cascade of a laser cavity and an optical amplifier which could be fabricated in the same microstructured fiber. In order to obtain realistic results, the simulation is performed by taking into account the spectroscopic parameters directly measured on preliminary samples of Dy3+:Ga5Ge20Sb10S65 glasses. The main objective is to investigate the feasibility of optical beam emission close to 4.4 μm wavelength. An output power of 547.3 mW with an input pump power of 3 W is calculated for an optical fiber about 1.5 m long and with a dopant concentration close to 6 × 1025 ions/m3. This result indicates that the designed source configuration is feasible for medium infrared light generation and it could find application in optical free propagation link, optical remote sensing and biomedicine.
Novel pumping schemes of Mid-IR photonic crystal fiber lasers for aerospace applications
The paper illustrates the design of two pumping schemes for Mid-IR lasers based on photonic crystal fibers (PCFs) made of dysprosium doped chalcogenide glass Dy3+:Ga5Ge20Sb10S65. The simulation is performed by taking into account the spectroscopic parameters measured on the rare earth-doped glass sample in order to perform a realistic feasibility investigation. The first pump scheme provides an optical beam emission close to 4400 nm wavelength by employing two pump beams at the wavelengths close to 2800 nm and 4100 nm, respectively. The second pump scheme allows beam emission close to 4400 nm wavelength via a 1700 nm pump, its efficiency is increased by including a suitable optical amplifier after the laser cavity. The proposed light sources based on chalcogenide glass photonic crystal fibers (PCFs) doped with Dy3+ ions are investigated via a home-made numerical model based on the coupled mode theory and solving the rare earth rate equations. A number of promising applications in different areas such as satellite remote sensing and aerospace, biology, molecular spectroscopy and environmental monitoring are feasible.
Rate equation analysis and energy transfer of Er3+-doped Ga2S3–GeS2–La2S3 glasses
Abstract Decay curves of 1.5 μm (4I13/2) and 1.0 μm (4I11/2) emissions from Er3+ ions in Ga2S3–GeS2–La2S3 glasses were measured by the excitation of a 1.5 μm and a 980 nm laser diode pump. The decay curves were simulated using rate equations for a model consisting of six levels of the Er3+ from the ground state. The rate equations contained five unknown parameters, i.e., excited state absorption cross sections of 4I13/2 → 4I9/2 (σesa24) for 1.5 μm excitation and 4I11/2 → 4F7/2 (σesa36) for 980 nm excitation, cooperative upconversion coefficients of (4I13/2, 4I13/2) → (4I9/2, 4I15/2) (C2) and (4I11/2, 4I11/2) → (4F7/2, 4I15/2) (C3), and an energy back-transfer coefficient of (4I9/2, 4I15/2) → (4I13/2, 4I13/2) (C2r). These parameters were estimated by fitting the simulated curves to the measured ones. The obtained values were σesa24=0.3×10−20 cm2, σesa36=0.5×10−20 cm2, C2=30–40×10−18 cm3/s, C3=20–25×10−18 cm3/s, and C2r=5×10−18 cm3/s.