van der Jjgm Jos Tol

Novel compact polarization converters based on ultra short bends

A novel integrated polarization converter based on ultra short bends is presented, which has a potential for low loss and small device size. A conversion value of 85% was experimentally measured with excess loss of 2.7 dB and overall dimensions of 975/spl times/83 /spl mu/m. Also 45% conversion was measured with extremely low excess loss of 0.4 dB for a device size of 760/spl times/86 /spl mu/m.

All-optical switching due to state filling in quantum dots

We report all-optical switching due to state filling in quantum dots (QDs) within a Mach–Zehnder interferometric switch (MZI). The MZI was fabricated using InGaAsP/InP waveguides containing a single layer of InAs/InP QDs. A 1530–1570 nm probe beam is switched by optical excitation of one MZI arm. By exciting below the InGaAsP band gap, we prove that the refractive index nonlinearity is entirely due to the QDs. The switching efficiency is 5 rad/(μW absorbed power), corresponding to a 6 fJ switching energy. Probe wavelength insensitivity was obtained using a broad size distribution of QDs.

A Compact Integrated Polarization Splitter/Converter in InGaAsP–InP

A novel design for an integrated passive polarization splitter/converter combination is presented. The device consists of a Mach-Zehnder interferometer with polarization converters in both arms. The device is analyzed using the transfer matrix method and fabricated in InGaAsP-InP. Measurement results show a splitting ratio of approximately 10 dB and a conversion of >90%. This device can be monolithically integrated with passive and active components.

A Single Etch-Step Fabrication-Tolerant Polarization Splitter

A tolerant single etch-step passive polarization splitter on InP/InGaAsP is designed and fabricated. The device consists of a directional coupler with a wide and a narrow waveguide. Modal birefringence of the third-order modes for transverse electric (TE) and transverse magnetic (TM) polarizations is employed to selectively couple one polarization. Tapering is applied to increase the tolerances. The devices are characterized, and the measurement results show good agreement with the beam-propagation-method simulations: a splitting ratio larger than 95% for a width range of around 100 nm and over a large wavelength range, covering at least the C-band

Short Polarization Converter Optimized for Active–Passive Integration in InGaAsP–InP

An improved design for an integrated polarization converter is presented. The device is designed for monolithic integration with active and passive components on InP-InGaAsP. A novel simplified fabrication process is demonstrated. Measured polarization conversion >97% over a wavelength range of >35 nm agrees well with simulations.

A generic foundry model for InP-based photonic ICs

Europe is making significant investments in development of generic photonic foundry platform infrastructures for InP-based and Silicon Photonic ICs. Here we present the present status for the InP-based JePPIX platform.

Reduction of Propagation Loss in Pillar-Based Photonic Crystal Waveguides

Out-of-plane losses are the major issue in the integration of two-dimensional photonic crystal devices in photonic integrated circuits. In this paper, we show that the out-of-plane losses of pillar-based photonic crystal waveguides can be vastly reduced, even for pillars with a low vertical index contrast, such as in InP/InGaAsP/InP technology. These low losses are obtained by creating confinement between the pillars with a polymer layer stack. We show that the spatial frequency component of the Bloch mode in the first Brillouin zone (i.e., the component inside the light cone), is significantly suppressed by the optimized polymer layer stack.

Power penalties due to Brillouin and Rayleigh scattering in a bidirectional coherent transmission system

In case of a large number of channels and a limited available optical bandwidth (limited laser tuning range) it may be necessary to chose a channel spacing near 0 or 11 GHz, where Rayleigh-and Brillouin backscattering introduce crosstalk in a bidirectional system. Although there is much literature on stimulated Brillouin scattering, that occurs at high powers, there is hardly any attention paid to what happens at relatively low input powers. Furthermore there are no system measurements which thoroughly investigate these effects. The authors performed extensive bidirectional system experiments to investigate the crosstalk from Brillouin scattering in more detail, including its polarization properties. They found, that, while for high powers most of the energy is backscattered to a 11 GHz lower frequency, for low powers there is no difference for the crosstalks at 11 GHz higher or 11 GHz lower than the signal frequency. The power budget is limited to 40 dB for both cases. The predicted 33.3% degree of polarization of low-power Brillouin scattering is experimentally confirmed for the first time.<<ETX>>

Ultrashort polarization converter on InP/InGaAsP fabricated by optical lithography

A compact, ultra short, integrated polarization converter has been fabricated by optical lithography. Length of the converter is 125 μm, and 325 μm including tapers. Conversion efficiency is higher than 95% and loss is less than 1 dB.

High-bandwidth uni-traveling carrier waveguide photodetector on an InP-membrane-on-silicon platform

A uni-traveling carrier photodetector (UTC-PD), heterogeneously integrated on silicon, is demonstrated. It is fabricated in an InP-based photonic membrane bonded on a silicon wafer, using a novel double-sided processing scheme. A very high 3 dB bandwidth of beyond 67 GHz is obtained, together with a responsivity of 0.7 A/W at 1.55 μm wavelength. In addition, open eye diagrams at 54 Gb/s are observed. These results promise high speed applications using a novel full-functionality photonic platform on silicon.