Flat-focal-field integrated spectrometer using a field-flattening lens.

We present a new flat-focal-field arrayed-waveguide grating (AWG) design that utilizes an integrated field-flattening lens placed in the second star coupler. The effective index difference between slab and lens region is obtained by introducing a thin silicon nitride (SiN) layer to a silicon oxynitride environment. Depending upon the SiN layer position, two different lens designs are implemented.

Improved arrayed-waveguide-grating layout avoiding systematic phase errors.

We present a detailed description of an improved arrayed-waveguide-grating (AWG) layout for both, low and high diffraction orders. The novel layout presents identical bends across the entire array; in this way systematic phase errors arising from different bends that are inherent to conventional AWG designs are completely eliminated. In addition, for high-order AWGs our design results in more than 50% reduction of the occupied area on the wafer.

Efficiency of integrated waveguide probes for the detection of light backscattered from weakly scattering media.

A semianalytical model for light collection by integrated waveguide probes is developed by extending previous models used to describe fiber probes. The efficiency of waveguide probes is compared to that of different types of fiber probes for different thicknesses of a weakly scattering sample. The simulation results show that integrated probes have a collection efficiency that is higher than that of small-core fiber probes, and, in the particular case of thin samples, also exceeds the collection efficiency of large-core highly multimode fiber probes.

Integrated approach to laser delivery and confocal signal detection.

We present an on-chip arrayed waveguide grating (AWG) sensor based on the confocal arrangement of two AWGs, one acting as focusing illuminator and one as signal collector. The chip can be close to, or in direct contact with, a sample, e.g.

Continuous-wave Nd-doped polymer lasers.

Continuous-wave laser operation at 1060.2 nm was demonstrated in polymer channel waveguides doped with a Nd complex above an absorbed pump threshold of 50 mW. The highest slope efficiency of 2.

170 Gbit/s transmission in an erbium-doped waveguide amplifier on silicon.

Signal transmission experiments were performed at 170 Gbit/s in an integrated Al(2)O(3):Er(3+) waveguide amplifier to investigate its potential application in high-speed photonic integrated circuits. Net internal gain of up to 11 dB was measured for a continuous-wave 1532 nm signal under 1480 nm pumping, with a threshold pump power of 4 mW. A differential group delay of 2 ps between the TE and TM fundamental modes of the 5.

Neodymium-complex-doped photodefined polymer channel waveguide amplifiers.

Channel waveguides based on a polymer, 6-fluorinated-dianhydride/epoxy, which is actively doped with a Nd complex, Nd(thenoyltrifluoroacetone)(3) 1,10-phenanthroline, are fabricated by a simple and reproducible procedure, spin coating a photodefinable cladding polymer onto a thermally oxidized silicon wafer, photopatterning, backfilling with the active core polymer, and spin coating with an upper cladding layer. Photoluminescence at 1060 nm from the Nd(3+) ions with a lifetime of 130 mus is observed. Optical gain at 1060 nm is demonstrated in channel waveguides with different Nd(3+) concentrations.

Two-photon fluorescence excitation using an integrated optical microcavity: a promising tool for biosensing of natural chromophores.

Application of an integrated optics (IO) microcavity (MC) for evanescent excitation of two-photon excited fluorescence (TPF) is demonstrated. The MC provides a high local intensity, which is required for the TPF, because of resonant enhancement of the intracavity power and a strong two-dimensional confinement of the guided mode. Numerical estimations show a large increase, by more than a factor of 10(4) of the TPF intensity at the MC compared to a conventional straight waveguide.

Densely integrated microring resonator based photonic devices for use in access networks.

Two reconfigurable optical add-drop multiplexers, operating in the second or third telecom window, as well as a 1x4x4 reconfigurable lambda-router operating in the second telecom window, are demonstrated. The devices have a footprint less than 2 mm(2) and are based on thermally tunable vertically coupled microring resonators fabricated in Si(3)N(4)/SiO(2).

Experimental study of bent multimode optical waveguides.

Bend losses of bent multimode waveguides have been experimentally studied. The results experimentally verify a simple analytical expression based on ray optics that can be used to determine bend losses in bent multimode waveguides. We have also shown that bend-induced losses in such multimode optical waveguides are wavelength independent.

Theory for the measurements of dispersion characteristics in waveguiding structures with a scanning near-field optical microscope.

A theory is presented for the interpretation of scanning near-field optical microscope measurements on pulses propagating in waveguiding structures. It is shown how the dispersion characteristics of the propagating guided modes may be derived from such experiments. Then it is demonstrated how to calibrate the scanning tip position and to derive experimental values for reflection and transmission of modes in identical single-mode waveguides connected to a photonic device such as a micro cavity.