Microstructured fibers for broadband wavefront filtering in the mid-IR

Abstract

The European Space Agency's space-based Darwin mission aims to directly detect extrasolar Earth-like planets using nulling interferometry. However, in order to accomplish this using current optical technology, the interferometer input beams must be filtered to remove local wavefront errors. Although short lengths of single-mode fiber are ideal wavefront filters, Darwin's operating wavelength range of 4 - 20 microm presents real challenges for optical fiber technology. In addition to the fact that step-index fibers only offer acceptable coupling efficiency over about one octave of optical bandwidth, very few suitable materials are transparent within this wavelength range. Microstructured optical fibers offer two unique properties that hold great promise for this application; they can be made from a single-material and offer endlessly single-mode guidance. Here we explore the advantages of using a microstructured fiber as a broadband wavefront filter for 4 - 20 microm.

Te-As-Se glass microstructured optical fiber for the middle infrared

“…In the present study, we focus on chalcogenide MOFs. Our work is motivated by the wide field of applications such as propagation of high intensity laser beams (i.e., CO 2 ) [15], broadband sources, sensors, and spatial filtering for realization 0003-6935/09/193860-06$15.00/0 © 2009 Optical Society of America of a nulling interferometer for exoplanet detection (DARWIN project) [7,16].…”

Recent advances in microstructured fibers for laser delivery and generation

“…It is to be appreciated that the use of ESM fibers in additional wavelength regimes has also become the focus of considerable attention with the first reports of such fibers being made in new materials such as Tellurite glass (transparent at wavelengths up to 5ȝm) [17] and in silver halides (capable of guiding light at wavelength beyond 20ȝm) [18]. As well as being of interest for high power laser delivery, such fibers are of use in applications such as modal filtering in spaceborne astronomy [19], and broadband mid-IR supercontinuum generation where the large effective area is helpful since it allows SC generation at high pulse energies [20]. This is important since the pulse energies achievable in small core soft glass fiber variants and not sufficient for many applications due the high nonlinearities per unit length and practical power handling thresholds.…”

Recent Advances in Microstructured Fibers for Power Delivery

“…Finally, it is to be appreciated that the use of ESM fibers in additional wavelength regimes has also become the focus of considerable attention with the first reports of such fibers being made in new materials such as Tellurite glass (transparent at wavelengths up to 5µm) [7] and in silver halides (capable of guiding light at wavelength beyond 20µm) [8]. As well as being of interest for high power laser delivery, such fibers are of use in applications such as modal filtering in space-borne astronomy [9], and broadband mid-IR supercontinuum generation [7].…”