Lm Luc Augustin

An introduction to InP-based generic integration technology

Photonic integrated circuits (PICs) are considered as the way to make photonic systems or subsystems cheap and ubiquitous. PICs still are several orders of magnitude more expensive than their microelectronic counterparts, which has restricted their application to a few niche markets. Recently, a novel approach in photonic integration is emerging which will reduce the R&D and prototyping costs and the throughput time of PICs by more than an order of magnitude. It will bring the application of PICs that integrate complex and advanced photonic functionality on a single chip within reach for a large number of small and larger companies and initiate a breakthrough in the application of Photonic ICs. The paper explains the concept of generic photonic integration technology using the technology developed by the COBRA research institute of TU Eindhoven as an example, and it describes the current status and prospects of generic InP-based integration technology.

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.

Monolithic AWG-based Discretely Tunable Laser Diode With Nanosecond Switching Speed

A novel concept for an arrayed-waveguide-grating (AWG)-based fast tunable laser is presented. It is fabricated in the InP-InGaAsP monolithic integration technology. Laser peaks have a sidemode suppression ratio of 30-40 dB. The wavelength switching speed is in the order of a few nanoseconds and switching is achieved by a 1-mA bias current. The switching between AWG channels is discrete and no laser operation takes place at wavelengths corresponding to other channels during the tuning process.

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.

Controlled polarization switching in VCSELs by means of asymmetric current injection

We have investigated the potential of asymmetric current injection for polarization switching in GaAs-based intracavity contacted vertical-cavity surface-emitting lasers using two sets of p- and n-type contacts per device. When using the contacts aligned along the [11~0] crystal direction, the observed laser polarization is parallel to [110], whereas, using the contacts along the [110] crystal direction, the polarization of the laser emission switches to a direction making an angle of 25/spl deg/-90/spl deg/ towards [110]. To overcome this peculiar result, a careful design of the contact layers in the intracavity structure is required.

Novel Widely Tunable Monolithically Integrated Laser Source

We report a novel type of monolithically integrated tunable semiconductor laser. The tuning is achieved by three intracavity Mach-Zehnder interferometers, realized in passive waveguides and using voltage-controlled electro-optic phase modulators requiring only four control voltages. The potential of the design is demonstrated by a realized laser system that shows an optical linewidth of 363 kHz, output power of 3 mW, and a record tuning range of 74.3 nm. Such a continuous wavelength span is in excess of any monolithic semiconductor laser reported up to date. Precision of the tuning mechanism is demonstrated by a scan over a 0.89-GHz-wide absorption line of acetylene. The laser design is suitable for a number of applications, including gas spectroscopy, telecommunication, and optical coherence tomography. The laser has been fabricated in a multi-project wafer run on an indium phosphide-based generic photonic foundry platform and demonstrates the potential of these technology platforms.

Integrated Parallel Spectral OCDMA En/Decoder

In this letter, a passive integrated device is presented that enables cost-effective parallel encoding and decoding in a spectral amplitude encoded optical code-division multiple-access transmission system. The device is monolithically integrated in InP-InGaAsP. Simulation and experimental results are given

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.

Monolithic Multiband Nanosecond Programmable Wavelength Router

A compact scalable reconfigurable multiwavelength router is proposed and demonstrated using an electronically gated cyclic router. Simultaneous wavelength-multiplexed channel allocation is performed with power penalties of 0.2-0.8 dB. Nanosecond timescale reconfiguration is achieved within a 2-ns guard band using semiconductor optical amplifier gates.