Thulium-doped tellurium oxide waveguide amplifier with 7.6 dB net gain on a silicon nitride chip: publisher's note.

This publisher's note contains corrections to Opt. Lett.44, 5788 (2019)OPLEDP0146-959210.

Thulium-doped tellurium oxide waveguide amplifier with 7.6 dB net gain on a silicon nitride chip.

We report on thulium-doped waveguide amplifiers integrated on a low-loss silicon nitride platform. The amplifier structure consists of a thulium-doped tellurium oxide thin film coated on a silicon nitride strip waveguide on silicon. We determine a waveguide background loss of 0.

Low-loss TeO-coated SiN waveguides for application in photonic integrated circuits.

We report on high-quality tellurium oxide waveguides integrated on a low-loss silicon nitride wafer-scale platform. The waveguides consist of silicon nitride strip features, which are fabricated using a standard foundry process and a tellurium oxide coating layer that is deposited in a single post-processing step. We show that by adjusting the SiN strip height and width and TeO layer thickness, a small mode area, small bend radius and high optical intensity overlap with the TeO can be obtained.

High-Q tellurium-oxide-coated silicon nitride microring resonators.

We report on tellurium-oxide (TeO)-coated silicon nitride microring resonators with internal quality factors up to 7.3×10, corresponding to 0.5 dB/cm waveguide loss, at wavelengths around 1550 nm.

TriPleX™ waveguide-based fluorescence biosensor for multichannel environmental contaminants detection.

In order to realize the multi-analyte assays for environmental contaminants, an optical biosensor utilizing laser-induced fluorescence-based detection via the binding of biomolecules to the surface of an integrated TriPleX™ waveguide chip on a glass substrate (fused silica, FS) is described. As far as we know, this is the first demonstration of using the TriPleX™ technology to fabricate the waveguide chip on a FS substrate. The sensor consists of 32 individually addressable sensor patches, which were formed on the chip surface by exploiting 3 Y-junction splitters, creating four equal rows of eight evanescently excited windows in parallel.

Low-loss, broadband and high fabrication tolerant vertically tapered optical couplers for monolithic integration of SiN and polymer waveguides.

A low-loss, broadband and high fabrication tolerant optical coupler for the monolithic integration of SiN and polymer waveguides is designed and experimentally demonstrated. The coupler is based on the adiabatic vertical tapering of the SiN waveguides. Low-loss operation is experimentally verified at both 976 and 1460-1635 nm wavelengths.

Sub-GHz-resolution C-band Nyquist-filtering interleaver on a high-index-contrast photonic integrated circuit.

Modern optical communications rely on high-resolution, high-bandwidth filtering to maximize the data-carrying capacity of fiber-optic networks. Such filtering typically requires high-speed, power-hungry digital processes in the electrical domain. Passive optical filters currently provide high bandwidths with low power consumption, but at the expense of resolution.

Integrated microwave photonic splitter with reconfigurable amplitude, phase, and delay offsets.

This work presents an integrated microwave photonics splitter with reconfigurable amplitude, phase, and delay offsets. The core components for this function are a dual-parallel Mach-Zehnder modulator, a deinterleaver, and tunable delay lines, all implemented using photonic integrated circuits. Using a demonstrator with an optical free spectral range of 25 GHz, we show experimentally the RF splitting function over two continuous bands, i.

On-chip visible-to-infrared supercontinuum generation with more than 495 THz spectral bandwidth.

We report ultra-broadband supercontinuum generation in high-confinement Si3N4 integrated optical waveguides. The spectrum extends through the visible (from 470 nm) to the infrared spectral range (2130 nm) comprising a spectral bandwidth wider than 495 THz, which is the widest supercontinuum spectrum generated on a chip.

Stress-optic modulator in TriPleX platform using a ezoelectric lead zirconate titanate (PZT) thin film.

We will demonstrate a stress-optic phase modulator in the passive SiN-based TriPleX platform using a layer of piezoelectric material. Regarding the stress-optic effect, the piezoelectric layer deposited on top of an optical waveguide is employed to control the phase of propagating light in the structure by applying an electrical field across the layer. In this work, it is demonstrated that the stress-optic effect lowers the power consumption by a factor of one million for quasi-DC operation and increases the modulation speed by three orders of magnitude, compared to currently used thermo-optic modulation in the TriPleX platform.

High confinement, high yield Si(3)N(4) waveguides for nonlinear optical applications.

In this paper we present a novel fabrication technique for silicon nitride (Si(3)N(4)) waveguides with a thickness of up to 900 nm, which are suitable for nonlinear optical applications. The fabrication method is based on etching trenches in thermally oxidized silicon and filling the trenches with Si(3)N(4). Using this technique no stress-induced cracks in the Si(3)N(4) layer were observed resulting in a high yield of devices on the wafer.

On-chip optical trapping and Raman spectroscopy using a TripleX dual-waveguide trap.

We present a new approach to the dual-beam geometry for on-chip optical trapping and Raman spectroscopy, using waveguides microfabricated in TripleX technology. Such waveguides are box shaped and consist of SiO2 and Si3N4, so as to provide a low index contrast with respect to the SiO2 claddings and low loss, while retaining the advantages of Si3N4. The waveguides enable both the trapping and Raman functionality with the same dual beams.

On-chip microwave photonic beamformer circuits operating with phase modulation and direct detection.

We propose and experimentally demonstrate the working principles of two novel microwave photonic (MWP) beamformer circuits operating with phase modulation (PM) and direct detection (DD). The proposed circuits incorporate two major signal processing functionalities, namely a broadband beamforming network employing ring resonator-based delay lines and an optical sideband manipulator that renders the circuit outputs equivalent to those of intensity-modulated MWP beamformers. These functionalities allow the system to employ low-circuit-complexity modulators and detectors, which brings significant benefits on the system construction cost and operation stability.

Ring resonator-based on-chip modulation transformer for high-performance phase-modulated microwave photonic links.

In this paper, we propose and experimentally demonstrate a novel wideband on-chip photonic modulation transformer for phase-modulated microwave photonic links. The proposed device is able to transform phase-modulated optical signals into intensity-modulated versions (or vice versa) with nearly zero conversion of laser phase noise to intensity noise. It is constructed using waveguide-based ring resonators, which features simple architecture, stable operation, and easy reconfigurability.

Si₃N₄ ring resonator-based microwave photonic notch filter with an ultrahigh peak rejection.

We report a simple technique in microwave photonic (MWP) signal processing that allows the use of an optical filter with a shallow notch to exhibit a microwave notch filter with anomalously high rejection level. We implement this technique using a low-loss, tunable Si₃N₄ optical ring resonator as the optical filter, and achieved an MWP notch filter with an ultra-high peak rejection > 60 dB, a tunable high resolution bandwidth of 247-840 MHz, and notch frequency tuning of 2-8 GHz. To our knowledge, this is a record combined peak rejection and resolution for an integrated MWP filter.

Silicon nitride microwave photonic circuits.

We present an overview of several microwave photonic processing functionalities based on combinations of Mach-Zehnder and ring resonator filters using the high index contrast silicon nitride (TriPleX™) waveguide technology. All functionalities are built using the same basic building blocks, namely straight waveguides, phase tuning elements and directional couplers. We recall previously shown measurements on high spurious free dynamic range microwave photonic (MWP) link, ultra-wideband pulse generation, instantaneous frequency measurements, Hilbert transformers, microwave polarization networks and demonstrate new measurements and functionalities on a 16 channel optical beamforming network and modulation format transformer as well as an outlook on future microwave photonic platform integration, which will lead to a significantly reduced footprint and thereby enables the path to commercially viable MWP systems.

Novel wideband microwave polarization network using a fully-reconfigurable photonic waveguide interleaver with a two-ring resonator-assisted asymmetric Mach-Zehnder structure.

We propose and demonstrate a novel wideband microwave photonic polarization network for dual linear-polarized antennas. The polarization network is based on a waveguide-implemented fully-reconfigurable optical interleaver using a two-ring resonator-assisted asymmetric Mach-Zehnder structure. For microwave photonic signal processing, this structure is able to serve as a wideband 2 × 2 RF coupler with reconfigurable complex coefficients, and therefore can be used as a polarization network for wideband antennas.

Novel microwave photonic fractional Hilbert transformer using a ring resonator-based optical all-pass filter.

We propose and demonstrate a novel wideband microwave photonic fractional Hilbert transformer implemented using a ring resonator-based optical all-pass filter. The full programmability of the ring resonator allows variable and arbitrary fractional order of the Hilbert transformer. The performance analysis in both frequency and time domain validates that the proposed implementation provides a good approximation to an ideal fractional Hilbert transformer.

System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications.

In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator true-time-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology.

Planar waveguides with less than 0.1 dB/m propagation loss fabricated with wafer bonding.

We demonstrate a wafer-bonded silica-on-silicon planar waveguide platform with record low total propagation loss of (0.045 ± 0.04) dB/m near the free space wavelength of 1580 nm.

Low-loss, high-index-contrast Si₃N₄/SiO₂ optical waveguides for optical delay lines in microwave photonics signal processing.

We report the design and characterization of Si₃N₄/SiO₂ optical waveguides which are specifically developed for optical delay lines in microwave photonics (MWP) signal processing applications. The waveguide structure consists of a stack of two Si₃N₄ stripes and SiO₂ as an intermediate layer. Characterization of the waveguide propagation loss was performed in race track-shaped optical ring resonators (ORRs) with a free-spectral range of 20 GHz and a bending radius varied from 50 μm to 125 μm.

On-chip CMOS compatible reconfigurable optical delay line with separate carrier tuning for microwave photonic signal processing.

We report, for the first time, an integrated photonic signal processor consisting of a reconfigurable optical delay line (ODL) with a separate carrier tuning (SCT) unit and an optical sideband filter on a single CMOS compatible photonic chip. The processing functionalities are carried out with optical ring resonators as building blocks. We show that the integrated approach together with the use of SCT technique allows the implementation of a wideband, fully-tunable ODL with reduced complexity.

Ultra-low-loss high-aspect-ratio Si3N4 waveguides.

We characterize an approach to make ultra-low-loss waveguides using stable and reproducible stoichiometric Si3N4 deposited with low-pressure chemical vapor deposition. Using a high-aspect-ratio core geometry, record low losses of 8-9 dB/m for a 0.5 mm bend radius down to 3 dB/m for a 2 mm bend radius are measured with ring resonator and optical frequency domain reflectometry techniques.

A photonic chip based frequency discriminator for a high performance microwave photonic link.

We report a high performance phase modulation direct detection microwave photonic link employing a photonic chip as a frequency discriminator. The photonic chip consists of five optical ring resonators (ORRs) which are fully programmable using thermo-optical tuning. In this discriminator a drop-port response of an ORR is cascaded with a through response of another ORR to yield a linear phase modulation (PM) to intensity modulation (IM) conversion.