Center for Ultrahigh bandwidth Devices for Optical Systems

Australia

Center for Ultrahigh bandwidth Devices for Optical Systems

Australia
SEARCH FILTERS
Time filter
Source Type

Riesen N.,University of Adelaide | Gross S.,Center for Ultrahigh bandwidth Devices for Optical Systems | Love J.D.,Australian National University | Withford M.J.,Center for Ultrahigh bandwidth Devices for Optical Systems
Optics Express | Year: 2014

We report the design and fabrication of three-dimensional integrated mode couplers operating in the C-band. These mode-selective couplers were inscribed into a boro-aluminosilicate photonic chip using the femtosecond laser direct-write technique. Horizontally and vertically written two-core couplers are shown to allow for the multiplexing of the LP11a and LP11b spatial modes of an optical fiber, respectively, with excellent mode extinction ratios (25-37 + dB) and low loss (∼1 dB) between 1500 and 1580 nm. Furthermore, optimized fabrication parameters enable coupling ratios close to 100%. When written in sequence, the couplers allow for the multiplexing of all LP01, LP11a and LP11b modes. This is also shown to be possible using a single 3-dimensional three-core coupler. These integrated mode couplers have considerable potential to be used in modedivision multiplexing for increasing optical fiber capacity. The three-dimensional capability of the femtosecond direct-write technique provides the versatility to write linear cascades of such two- and three-core couplers into a single compact glass chip, with arbitrary routing of waveguides to ensure a small footprint. This technology could be used for highperformance, compact and cost-effective multiplexing of large numbers of modes of an optical fiber. © 2014 Optical Society of America.


Ma P.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Ma P.,Beihang University | Choi D.-Y.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Yu Y.,Center for Ultrahigh Bandwidth Devices for Optical Systems | And 5 more authors.
Optics Express | Year: 2013

We report the characteristics of low-loss chalcogenide waveguides for sensing in the mid-infrared (MIR). The waveguides consisted of a Ge 11.5As24Se64.5 rib waveguide core with a 10nm fluoropolymer coating on a Ge11.5As24S64.5 bottom cladding and were fabricated by thermal evaporation, photolithography and ICP plasma etching. Over most of the functional group band from 1500 to 4000cm-1 the losses were < 1dB/cm with a minimum of 0.3dB/cm at 2000cm-1. The basic capabilities of these waveguides for spectroscopy were demonstrated by measuring the absorption spectrum of soluble Prussian blue in Dimethyl Sulphoxide. © 2013 Optical Society of America.


Spaleniak I.,Macquarie University | Gross S.,Macquarie University | Gross S.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Jovanovic N.,Japan National Astronomical Observatory | And 7 more authors.
Laser and Photonics Reviews | Year: 2014

The first demonstration of narrowband spectral filtering of multimode light on a 3D integrated photonic chip using photonic lanterns and waveguide Bragg gratings is reported. The photonic lanterns with multi-notch waveguide Bragg gratings were fabricated using the femtosecond direct-write technique in boro-aluminosilicate glass (Corning, Eagle 2000). Transmission dips of up to 5 dB were measured in both photonic lanterns and reference single-mode waveguides with 10.4-mm-long gratings. The result demonstrates efficient and symmetrical performance of each of the gratings in the photonic lantern. Such devices will be beneficial to space-division multiplexed communication systems as well as for units for astronomical instrumentation for suppression of the atmospheric telluric emission from OH lines. © 2013 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Spaleniak I.,Macquarie University | Jovanovic N.,Japan National Astronomical Observatory | Gross S.,Macquarie University | Gross S.,Center for Ultrahigh Bandwidth Devices for Optical Systems | And 6 more authors.
Optics Express | Year: 2013

There are numerous advantages to exploiting diffraction-limited instrumentation at astronomical observatories, which include smaller footprints, less mechanical and thermal instabilities and high levels of performance. To realize such instrumentation it is imperative to convert the atmospheric seeing-limited signal that is captured by the telescope into a diffraction-limited signal. This process can be achieved photonically by using a mode reformatting device known as a photonic lantern that performs a multimode to single-mode transition. With the aim of developing an optimized integrated photonic lantern, we undertook a systematic parameter scan of devices fabricated by the femtosecond laser direct-write technique. The devices were designed for operation around 1.55 μm. The devices showed (coupling and transition) losses of less than 5% for F/# ≥ 12 injection and the total device throughput (including substrate absorption) as high as 75-80%. Such devices show great promise for future use in astronomy. ©2013 Optical Society of America.


Thomas J.U.,Friedrich - Schiller University of Jena | Jovanovic N.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Kramer R.G.,Friedrich - Schiller University of Jena | Marshall G.D.,Center for Ultrahigh Bandwidth Devices for Optical Systems | And 4 more authors.
Optics Express | Year: 2012

Highly localized fiber Bragg gratings can be inscribed point-by-point with focused ultrashort pulses. The transverse localization of the resonant grating causes strong coupling to cladding modes of high azimuthal and radial order. In this paper, we show how the reflected cladding modes can be fully analyzed, taking their vectorial nature, orientation and degeneracies into account. The observed modes' polarization and intensity distributions are directly tied to the dispersive properties and show abrupt transitions in nature, strongly correlated with changes in the coupling strengths. © 2012 Optical Society of America.


Wolff C.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Wolff C.,University of Sydney | Stee M.J.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Stee M.J.,Macquarie University | And 2 more authors.
Optics Express | Year: 2014

We derive formal selection rules for Stimulated Brillouin Scattering (SBS) in structured waveguides. Using a group-theoretical approach, we show how the waveguide symmetry determines which optical and acoustic modes interact for both forward and backward SBS. We present a general framework for determining this interaction and give important examples for SBS in waveguides with rectangular, triangular and hexagonal symmetry. The important role played by degeneracy of the optical modes is illustrated. These selection rules are important for SBS-based device design and for a full understanding the physics of SBS in structured waveguides. © 2014 Optical Society of America


Wolff C.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Wolff C.,University of Sydney | Soref R.,University of Massachusetts Boston | Poulton C.G.,Center for Ultrahigh Bandwidth Devices for Optical Systems | And 3 more authors.
Optics Express | Year: 2014

In a theoretical design study, we propose buried waveguides made of germanium or alloys of germanium and other group-IV elements as a CMOS-compatible platform for robust, high-gain stimulated Brillouin scattering (SBS) applications in the mid-infrared regime. To this end, we present numerical calculations for backward-SBS at 4mm in germanium waveguides that are buried in silicon nitride. Due to the strong photoelastic anisotropy of germanium, we investigate two different orientations of the germanium crystal with respect to the waveguide's propagation direction and find considerable differences. The acoustic wave equation is solved including crystal anisotropy; acoustic losses are computed from the acoustic mode patterns and previously published material parameters. © 2014 Optical Society of America.


Arriola A.,Macquarie University | Arriola A.,Center for Ultrahigh bandwidth Devices for Optical Systems | Arriola A.,University of Navarra | Gross S.,Macquarie University | And 10 more authors.
Optics Express | Year: 2013

We present a novel method to fabricate low bend loss femtosecond-laser written waveguides that exploits the differential thermal stabilities of laser induced refractive index modifications. The technique consists of a two-step process; the first involves fabricating large multimode waveguides, while the second step consists of a thermal postannealing process, which erases the outer ring of the refractive index profile, enabling single mode operation in the C-band. By using this procedure we report waveguides with sharp bends (down to 16.6 mm radius) and high (80%) normalized throughputs. This procedure was used to fabricate an efficient 3D, photonic device known as a "pupil- remapper" with negligible bend losses for the first time. The process will also allow for complex chips, based on 10's - 100's of waveguides to be realized in a compact foot print with short fabrication times. © 2013 Optical Society of America.


Wolff C.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Wolff C.,University of Sydney | Steel M.J.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Steel M.J.,Macquarie University | And 4 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Recent theoretical studies of stimulated Brillouin scattering (SBS) in nanoscale devices have led to intense research effort dedicated to the demonstration and application of this nonlinearity in on-chip systems. The key feature of SBS in integrated photonic waveguides is that small, high-contrast waveguides are predicted to experience powerful optical forces on the waveguide boundaries, which are predicted to further boost the SBS gain that is already expected to grow dramatically in such structures because of the higher mode confinement alone. In all recent treatments, the effect of radiation pressure is included separately from the scattering action that the acoustic field exerts on the optical field. In contrast to this, we show here that the effects of radiation pressure and motion of the waveguide boundaries are inextricably linked. Central to this insight is a new formulation of the SBS interaction that unifies the treatment of light and sound, incorporating all relevant interaction mechanisms - radiation pressure, waveguide boundary motion, electrostriction, and photoelasticity - from a rigorous thermodynamic perspective. Our approach also clarifies important points of ambiguity in the literature, such as the nature of edge effects with regard to electrostriction and of body forces with respect to radiation pressure. This new perspective on Brillouin processes leads to physical insight with implications for the design and fabrication of SBS-based nanoscale devices. © 2015 American Physical Society. ©2015 American Physical Society.


Cvetojevic N.,Macquarie University | Cvetojevic N.,Center for Ultrahigh Bandwidth Devices for Optical Systems | Jovanovic N.,Macquarie University | Jovanovic N.,Anglo Australian Observatory | And 5 more authors.
Optics Express | Year: 2012

With the aim of utilizing arrayed waveguide gratings for multiobject spectroscopy in the field of astronomy, we outline several ways in which standard telecommunications grade chips should be modified. In particular, by removing the parabolic-horn taper or multimode interference coupler, and injecting with an optical fiber directly, the resolving power was increased threefold from 2400 ± 200 (spectral resolution of 0.63 ± 0.2 nm) to 7000 ± 700 (0.22 ± 0.02 nm) while attaining a throughput of 77 ± 5%. More importantly, the removal of the taper enabled simultaneous off-axis injection from multiple fibers, significantly increasing the number of spectra that can be obtained at once (i.e. the observing efficiency). Here we report that ∼12 fibers can be injected simultaneously within the free spectral range of our device, with a 20% reduction in resolving power for fibers placed at 0.8 mm off-centre. © 2012 Optical Society of America.

Loading Center for Ultrahigh bandwidth Devices for Optical Systems collaborators
Loading Center for Ultrahigh bandwidth Devices for Optical Systems collaborators