Showing papers by "Norihiko Nishizawa published in 2021"

Dispersion-managed, high-power, Tm-doped ultrashort pulse fiber laser using single-wall-carbon-nanotube polyimide film

Abstract: We demonstrated a dispersion-managed, high-power, Tm-doped ultrashort pulse fiber laser using a single-wall-carbon-nanotube (SWNT) polyimide film. SWNTs with a diameter of 1.6 nm were synthesized with the enhanced direct injection pyrolytic synthesis (e-DIPs) method, and thin polyimide films in which SWNTs were dispersed were developed as saturable absorbers in the wavelength range λ = 1.8–2.0 µm. An all-fiber type, passively mode-locked, ultrashort-pulse Tm-doped fiber laser was demonstrated using the developed SWNT films. Wavelength tuning operation with gain fiber control and dispersion management of the developed fiber laser were investigated. Stable soliton and dissipative soliton mode locking operations were observed. High-power (102.6 mW) single-pulse mode-locking operation was achieved in a large positive dispersion regime. The repetition rate was 21.6 MHz, and the corresponding pulse energy was 4.75 nJ. To the best of our knowledge, this is the highest power operation of a Tm-doped fiber laser using carbon nanotubes and film-type devices with nano-carbon materials. The developed laser showed self-staring, stable performance and is useful for practical applications.

Development of Supercontinuum Laser Source for 2 μm OCT with Tm-Ho co-doped Ultrashort Pulse Fiber Laser Using Single Wall Carbon Nanotube

Abstract: Highly efficient Tm-Ho co-doped ultrashort pulse fiber laser operating at 1.9 μm was developed using single wall carbon nanotube. Wideband supercontinuum at 2.0 μm was generated and high-resolution OCT imaging of human tooth was demonstrated.

Characteristics of Spectral Peaking in Coherent Supercontinuum Generation

Abstract: Spectral peaking during supercontinuum generation in normal dispersive highly nonlinear fiber was investigated both numerically and experimentally. Sharp multiple spectral peaks were generated stably with 290 GHz frequency interval, and low noise properties were confirmed.