Broadband Continuously Tunable All-Fiber Laser Based on OPG for CARS Imaging

Abstract

A broadband continuously tunable SESAM all-fiber laser based on optical parametric generation (OPG) for Coherent anti-Stokes Raman Scattering (CARS) imaging applications is presented in this article. This laser structure is built on allpolarization maintaining fibers yielding high environmental stability. The OPG is based on PM photonic crystal fiber as parametric gain pumped by a wavelength-tunable (1025 nm to 1055 nm) and repetition rate-tunable (3 MHz to 500 KHz) Ybdoped pulsed fiber laser. The all-fiber structure features free polarization adjustment in slow-axis tunable operation with a wavelength range from 770 to 940 nm for signal radiation and 1225 to 1510 nm for idler radiation. The pump and signal pulses (CARS-Stokes and CARS-pump respectively) are intrinsically overlapped, both spatially and temporarily, due to the four-wave mixing (FWM) generation and emitted from a single fiber end. The CARS-Stokes and CARS-pump pulse duration vary between 25 to 32 ps and 21 to 24 ps respectively in the whole band, ensuring a good overlap of the generated signals, and both exhibit a Gaussian profile with high spatial beam quality. The frequency conversion allows to obtain a frequency difference between the generated signals from 1100 to 3300− . The reported low-cost laser source is ideal for bio-imaging applications, especially in CARS imaging, due to its compactness, simplicity, robustness and ease of handling. A patent has been filed based on this technology.

All-spliced 11.3 W four-wave mixing fiber source at 760 nm

“…By contrast, all-spliced fiber sources would be attractive for their mechanical and vibrational resistance. All spliced systems have been shown at low power for medical applications [14] and at the Watt level in the visible [15], [16]. We have previously reported an all spliced FWM source with 7.9 W of power in the 750 -820 nm band [16] with 27 % efficiency (defined as the ratio of the in-band FWM power to the total transmitted power).…”

Methods of Radiation Wavelength Tuning in Short-Pulsed Fibre Lasers

“…One should not forget the classical non-linear approaches to broadening the output spectral range, including harmonic generation [10], parametric generation [11], and soliton self-frequency shift [12]. By now, a substantial range of components and methods have been created for tuning the output wavelength of short-pulsed fibre lasers that need analysis and identification of the best solutions.…”