Development of wavelength tunable mode-locked fiber laser in the mid-IR

Lasers have been used in the area of healthcare- for diagnostic, therapeutic, and surgical applications since the past two or three decades. The wavelength range of 1950-2100 nm is specifically significant due to large water absorption in these wavelengths; leading to applications in laser-based surgery, lithotripsy, and for nonlinear imaging. In addition, these wavelength ranges find several other applications including fiber optic communication; free space communication, Lidar, spectroscopy and sensing. Building these lasers in an all-fiber configuration gives the benefit of a compact design with minimal thermal issues.

Most of the applications in these wavelength ranges require wavelength tunable pulses with adjustable repetition rates and energy levels. This project aims at building a prototype fiber-based mode locked laser, which is tunable in the wavelength range 1950-2100 nm and with tunable energy levels. We propose to achieve this in a two-stage configuration. The first stage would comprise of an actively mode locked laser with thulium doped fiber as the gain medium, and the second stage would comprise of a power amplifier with a double clad fiber with multiple pumps.