Laser written glass interposer for fiber coupling to silicon photonic integrated circuits

Recent advancements in photonic-electronic integration push towards denser multichannel fiber to silicon photonic chip coupling solutions. However, current packaging schemes based on suitably polished fiber arrays do not provide sufficient scalability. Alternatively, lithographically-patterned fused silica glass interposers have been proposed, allowing for the integration of fanout waveguides between a dense array of on-chip silicon waveguides and a cleaved fiber ribbon. In this paper, we propose the use of femtosecond laser inscription for the fabrication of the fused silica glass interposer, allowing for a monolithic integration of waveguides and V-grooves for fiber alignment. The waveguides obtained by Femtosecond Laser Direct Writing (FLDW) have a propagation loss of 0.88 dB/cm at 1550 nm. The mode-field diameter is 12.8 +/- 0.4 mu m, allowing for a coupling loss of 1.24 +/- 0.32 dB when coupling to a standard single mode optical fiber, passively aligned to the fused silica waveguide by insertion in a V-groove created by Femtosecond Laser Irradiation followed by Chemical Etching (FLICE). The average surface roughness of the etched waveguide facet is 160 +/- 5 nm. Scattering loss when coupling to fiber is reduced by use of an index-matching adhesive for fiber fixation. A polished out-of-plane coupling mirror at an angle of 41.5. injects the light into standard grating couplers, providing a quasi-planar fiber-to-chip package. The excess loss of the proposed solution is limited to 2 dB per interface, including mirror, waveguide and fiber coupling losses

Smart liquid crystal beam deflector with laser ablated polymer micro grating structure

LC beam steering devices are realized using the combination of liquid crystal and polymer micro grating structures. The micro gratings are fabricated by combining two major techniques: laser ablation for a master mold and soft lithography for replicas with the desired optical materials. The LC components demonstrate effective beam deflections with a steering angle of 2.6° for both polarized monochromatic light (deflection efficiency >40%) and unpolarized white light beam (deflection efficiency >30%)

Adaptive patterning of optical and electrical fan-out for photonic chip packaging

Packaging and assembly challenges for photonic chips still need to be addressed in order to enable rapid deployment in mass-market production. Integration and assembly solutions that not only enable ease of packaging but also allow a dense co-integration of the electronic and photonic ICs are essential. In that context, we demonstrate an adaptive patterning of both optical and electrical fan-out for face-up electronic-photonic integration. For the optical fan-out, we developed an approach based on adiabatic optical coupling between single-mode polymer waveguides and silicon waveguides on a silicon photonic chip. The polymer waveguides were directly patterned on the silicon photonic chip by direct-write lithography (DWL). The electrical interconnects between a photonic chip and electronic IC are realized by employing high-speed silver interconnects using aerosol-jet printing (AJP), as a promising alternative for the traditional bond-wires. Furthermore, a direct comparison between the AJP interconnects and the conventional bond-wires is established. Finally, an NRZ optical transmitter has been successfully demonstrated based on the AJP interconnection and clear open eye diagrams were obtained at 56 Gb/s

Femtosecond laser-inscribed non-volatile integrated optical switch in fused silica based on microfluidics-controlled total internal reflection

We demonstrate a non-volatile optical power switch, fabricated by femtosecond laser inscription in a fused silica substrate, with switching operation based on microfluidics-controlled total internal reflection. The switch consists of crossed waveguides and a rectangular, high aspect ratio microfluidic channel, located at the waveguide crossing. The switching between total internal reflection and transmission at the channel wall is determined by the refractive index of the medium inside the channel. Femtosecond laser inscription allows for co-integration of low-loss optical waveguides and channels with smooth sidewalls and thus the fabrication of low insertion loss switches that are broadband and show low polarization dependent losses. The measured total internal reflection loss of the fabricated switch is about 1.5dB at the wavelength 1550 nm. The loss due to transmission through the channel filled with refractive index matching liquid is about 0.5 dB. Detailed finite difference time domain and beam propagation method simulations of the switch's performance indicate that the losses can be further reduced by optimizing its geometry, together with further adjusting the inscription parameters

Non-volatile microfluidics controlled switch fabricated in fused silica by femtosecond laser inscription

The spreading of fiber to the home technology, driven by the increasing amount of internet traffic over the past decade, requires development of optical power switches (OPSs) for efficient optical network management. Microfluidic Silicon photonics OPSs have recently been proposed as a new class of non-volatile, easily (remotely) reconfigurable switches that could increase the flexibility of a network and help reduce the maintenance costs. As the switching state is controlled by microfluidics, the OPS needs to be powered only at the moment when it needs to be reconfigured

Laser ablation of micro-photonic structures for efficient light collection and distribution

In this work we report the fabrication of polymer micro-photonic gratings for use in liquidcrystal based actively tunable electro-optic components. The gratings are produced by moving the sample surface sideways across a perpendicularly impinging KrF excimer laser beam (lambda = 248 nm), which is shaped by specially designed triangular and trapezoidal masks. To obtain correctly dimensioned and smooth grating surfaces, different materials (SU-8, polycarbonate, Epoclad and Epocore) are subjected to the laser ablation with optimized laser processing parameters. The resulting grating structures on Epocore exhibit the best surface roughness and dimensional fidelity. Optionally, spacers for maintaining the cell gap of the superimposed liquid crystal layer can also be fabricated in the same process. Two different methods were demonstrated: overlapping ablation and double mask ablation. Micro-grating structures were produced that deflect a monochromatic (543 nm) laser beam to the theoretically predicted 11th order with an angle of 7 degrees

Micro-photonic structures for efficient light collection and distribution by laser ablation /

Master of Science in de ingenieurswetenschappen: fotonic

Laser processing for large area polymer photonic applications

In the last years polymer photonics experienced a tremendous boost in research efforts, targeting for applications in short-reach optical interconnects, biosensing, medical diagnostics, multi-axial strain sensing, datastorage, etc. Polymers are relatively inexpensive, can be functionalized to achieve required optical, electronic, or mechanical properties, and have demonstrated compatibility with various patterning methods. We highlight our recent research efforts, challenges, and opportunities in the development of novel laser processes for defining complex polymer photonic components or structures, and how to integrate them into a common polymer platform. Laser direct write lithography has been selected as a promising approach for large area polymer optical waveguide definition. Experimental results are presented for a number of commercially available polymers, both for multi-mode and single mode waveguides. In- and outcoupling is provided by 45 degree micro-mirrors, which are defined by UV-laser ablation. Hybrid integration of laser and photodiode chips is provided by a low temperature flip-chip assembly process, enabled by laser-induced forward-printing for high-accuracy deposition of solder or conductive adhesives. Integration of pixelated organic LEDs onto the polymer platform is studied, for which a layer selective laser patterning process is investigated, using conventional nano-, and picosecond pulsed lasers in the visible and near-IR, together with novel lasers targetting for resonant mid-IR ablation