Two Octaves Supercontinuum Generation in Lead-Bismuth Glass Based Photonic Crystal Fiber.

Ryszard Buczynski,Andrew Waddie,Ryszard Stepien,Ajoy Kar,Henry Bookey,Mariusz Klimczak,Tadeusz Martynkien,Dariusz Pysz,Mohammad R Taghizadeh,John Mccarthy

doi:10.3390/ma7064658

Abstract

In this paper we report a two octave spanning supercontinuum generation in a bandwidth of 700–3000 nm in a single-mode photonic crystal fiber made of lead-bismuth-gallate glass. To our knowledge this is the broadest supercontinuum reported in heavy metal oxide glass based fibers. The fiber was fabricated using an in-house synthesized glass with optimized nonlinear, rheological and transmission properties in the range of 500–4800 nm. The photonic cladding consists of 8 rings of air holes. The fiber has a zero dispersion wavelength (ZDW) at 1460 nm. Its dispersion is determined mainly by the first ring of holes in the cladding with a relative hole size of 0.73. Relative hole size of the remaining seven rings is 0.54, which allows single mode performance of the fiber in the infrared range and reduces attenuation of the fundamental mode. The fiber is pumped into anomalous dispersion with 150 fs pulses at 1540 nm. Observed spectrum of 700–3000 nm was generated in 2 cm of fiber with pulse energy below 4 nJ. A flatness of 5 dB was observed in 950–2500 nm range.

Highlights

A considerable amount of research work related to supercontinuum generation in photonic crystal fibers (PCFs) has, to date, been focused on the more conventional, mainly silica-based fibers operating in the visible and near-infrared (NIR) [1]
(900–2400 nm), under pumping with Er-doped fiber laser, which was passively mode-locked with a graphene saturable absorber and comprised a chirp-pulse amplification (CPA) block, generating 850 fs pulses at 1560 nm [15] and 400 fs [16]
We reduced the relative hole size to d/Λ = 0.54 in the outer rings

Summary

Introduction

A considerable amount of research work related to supercontinuum generation in photonic crystal fibers (PCFs) has, to date, been focused on the more conventional, mainly silica-based fibers operating in the visible and near-infrared (NIR) [1]. We have reported successful use of the same fiber for an octave spanning supercontinuum (900–2400 nm), under pumping with Er-doped fiber laser, which was passively mode-locked with a graphene saturable absorber and comprised a chirp-pulse amplification (CPA) block, generating 850 fs pulses at 1560 nm [15] and 400 fs [16] To our knowledge this is the broadest supercontinuum reported up to now in heavy metal oxide glasses. Linear and nonlinear characterization data on the fiber is shown and discussed and a general comparison of supercontinuum pumping performance demonstrated in this work is given in relation to previous experiments This approach would allow the use of cost-efficient and robust 1560 nm femtosecond fiber lasers as pump sources in the near future

Nonlinear Single Mode Photonic Crystal Fiber

Experimental Results

Conclusions