Design of segmented cladding fiber for femtosecond laser pulse delivery at 1550 and 1064 nm wavelengths

Abstract

Segmented cladding fiber (SCF) is capable of single mode operation over an extended range of wavelengths while maintaining large mode area. In this paper we report the design of an SCF with mode area as large as 1,825 \(\upmu \hbox {m}^{2}\), suitable for delivery of high peak power femtosecond laser pulses at 1550 and 1064 nm wavelengths. An SCF with such a large-mode area is a few-moded fiber and its design requires careful choice of design parameters to have robustness against mode-coupling effects and bend loss. In this paper we address these issues and report a design of an SCF showing near distortion-free propagation of 100-fs, 53-kW peak power pulses at 1550-nm wavelength with 1,825-\(\upmu \hbox {m}^{2}\) mode area through fundamental mode. The same fiber can also deliver 250-fs, 15-kW peak power pulses at 1064-nm wavelength with 1,793-\(\upmu \hbox {m}^{2}\) mode area. The fiber has been analyzed by using the radial effective-index method in conjunction with transfer matrix method and the pulse propagation has been studied by solving the nonlinear Schroedinger equation by split-step Fourier method. Such a fiber would find applications in multiphoton microscopy and in biomedical engineering.