Jjgm Jos van der Tol

Transmission of pillar-based photonic crystal waveguides in InP technology

Waveguides based on line defects in pillar photonic crystals have been fabricated in InP∕InGaAsP∕InP technology. Transmission measurements of different line defects are reported. The results can be explained by comparison with two-dimensional band diagram simulations. The losses increase substantially at mode crossings and in the slow light regime. The agreement with the band diagrams implies a good control on the dimensions of the fabricated features, which is an important step in the actual application of these devices in photonic integrated circuits.

Photonic integration in Indium-Phosphide Membranes on Silicon (IMOS)

A new photonic integration technique is presented, based on the use of an indium phosphide membrane on top of a silicon chip. This can provide electronic chips (CMOS) with an added optical layer (IMOS) for resolving the communication bottleneck. A major advantage of InP is the possibility to integrate passive and active components (SOAs, lasers) in a single membrane. In this paper we describe progress achieved in both the passive and active components. For the passive part of the circuit we succeeded to bring the propagation loss of our circuits close to the values obtained with silicon; we achieved propagation loss as low as 3.3 dB/cm through optimization of the lithography and the introduction of C60 (fullerene) in an electro resist. Further we report the smallest polarisation converter reported for membrane waveguides ( <10 μm) with low-loss (< 1 dB from 1520- 1550 nm), > 95% polarisation conversion efficiency over the whole C-band and tolerant fabrication. We also demonstrate an InP-membrane wavelength demultiplexer with a loss of 2.8 dB, a crosstalk level of better than 18 dB and a uniformity over the 8 channels of better than 1.2 dB. For the integration of active components we are testing a twin guide integration scheme. We present our design based on optical and electrical simulations and the fabrication techniques.

Planar Concave Grating Demultiplexers on an InP-Membrane-on-Silicon Photonic Platform

We present measurement results of a 0.25 mm2 footprint eight-channel planar concave grating demultiplexer fabricated in a 300-nm-thick InP membrane adhesively bonded to silicon. The measured cross-talk between the different channels of the device is better than -18 dB, while the insertion loss is 2.8 dB. The power non-uniformity between the channels is 1.2 dB.

Improved fabrication process of low-loss and efficient polarization converters in InP-based photonic integrated circuits

We show an improved fabrication process of trapezoidal polarization converters for InP-based photonic integrated circuits. The new process has reduced complexity, and the fabricated converters have loss two times lower than reported previously. The measurements of the converters show an efficiency of polarization conversion of 97.9% at a wavelength of 1.535 μm and loss below 0.5 dB.

First demonstration of an electrically pumped laser in the InP Membrane on silicon platform

We demonstrate the first electrically pumped laser in the “InP membrane on Si” platform. With pulsed current injection, the lasing occurs at threshold current of 200mA and peak optical power of 135µW in fiber.

Ultra-Sharp and Highly Tolerant Waveguide Bends for InP Photonic Membrane Circuits

In this letter, we present a sharp bend design for the InP-based photonic membrane, which shows low loss and high tolerance. The traditional arc bends on InP membranes face high loss when the bending radii reduce below 2

ICP etching of InP and its applications in photonic circuits

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Integrated High-Performance TE/TM Converters for Polarization Independence in Semiconductor Optical Amplifiers

. In addition, their performance deteriorates even more dramatically at the presence of waveguide footings. The proposed design has the advantages of low loss, high compactness, wide spectral response, and ease of fabrication. It is also verified to be much more resilient to design and fabrication variations, such as waveguide footings. The sharp bend is fabricated together with traditional arc bends. Experimental results confirm its potential as a basic building block for InP photonic membrane platforms.

New fabrication method of trapezoidal polarization converters for inp-based photonic integrated circuits

Ridge waveguides with smooth and vertical sidewalls are essential in photonic circuits. We have investigated waveguide realization with reactive ion etching of InP and InP-based structures using a SiNx in a Cl2/H2/CH4 chemistry in an ICP plasma. Depending on ICP power and RF power, etching rates can be obtained from 200 nm/min up to > 2μm/min. A maximum etching selectivity of InP vs SiNx of 12 was obtained at 2000 W of ICP power. Deep etched waveguides, fabricated in an InP/InGaAsP double heterostructure, show typical losses of 2 dB/cm. This low value shows the potential of ICP technique in the fabrication of photonic circuits.

Towards a Fully Integrated Indium-Phosphide Membrane on Silicon Photonics Platform

Integrated polarization converters (PCs) with high (>99%) conversion efficiency open up many new possibilities in an InP-based photonic integrated circuit. In this paper, we describe how such a PC can be added to a circuit containing semiconductor optical amplifiers (SOAs), in order to obtain polarization independent amplification. Polarization independence is obtained by placing the PC halfway between two identical SOA sections. This approach has the advantage that no compromises in design and fabrication are needed. The polarization conversion is found to be very high, above 99.5%, when using a tolerant two-section PC. The extra insertion loss due to the converter is below 0.5 dB. The polarization-dependent gain (PDG) of the SOA reduces from 17 dB to only 0.3 dB by the inclusion of the PC. This is comparable to the best PDG values found in the literature with other techniques. The reduction is achieved over the whole C-band and for varying pump currents.