S-matix oriented CAD-tool for photonic integrated circuits

\u3cp\u3eA scattering matrix oriented CAD tool is presented for design and simulation of photonic integrated circuits. In a scattering matrix approach each component is represented by a scattering matrix which describes the signal transfer between the different ports of the component. These components are usually waveguides. As an example of a more complicated component simulation of an optical PHASAR demultiplexer will be described and the potential of the approach will be illustrated in simulating an integrated add-drop multiplexer and comparing the results with measurement data of a realized device.\u3c/p\u3

Developments in arrayed waveguide grating devices for photonic integrated circuits

Arrayed waveguide grating (AWG) devices play a crucial role in wavelength division multiplexing (WDM) networks and links. AWGs are key building blocks in multi-wavelength receivers and transmitters, wavelength routers, add-drop multiplexers and optical crossconnects. AWG size becomes a critical issue when they are used in higher complexity photonic integrated circuits. The last years have shown a steady reduction of AWG device dimensions in silica-on-silicon, silicon-on-insulator and InP-based technologies. Extremely compact AWGs with good performance are feasible and allow for a significant reduction in cost, when integrated with other components in photonic integrated circuits

An InP-based integrated modulated coherent state source for differential phase shift quantum key distribution

A low-cost integrated differential phase shift QKD transmitter, which consist of a distributed Bragg reflector laser, a phase modulator, and Mach-Zehnder modulator sections for pulse carving and optical attenuation is presented. Initial characterization results of the laser, and the modulator sections are demonstrated

Optimized MMI coupler shape for reduced back-reflections

Spurious back-reflections can be a source of concern in photonic integrated circuits. This is especially true in circuits containing amplifiers, but even in passive circuits, small reflections can already have a strong influence on circuit performance. It is known that strong back-reflections can be present when using a 2×1 MMI as a combiner. We investigate methods for reducing these spurious reflections in a generic integration technology. We present a novel MMI shape which is able to reduce reflections by more than 20 dB

Fast and robust method for measuring semiconductor optical amplifier gain

\u3cp\u3eIn this paper, we present a new, robust multipoint fitting method for gain measurement with a metric for quality estimation of the procedure. The method is able to identify the deleterious effect of imperfections within the test structures, is tolerant to optical coupling errors and is well suited to high throughput, generic, automated testing of semiconductor optical amplifiers. Gain is estimated in a range of pump current densities over multiple spectral bands from 1400 to 1600 nm with a standard error in the order of 1/cm.\u3c/p\u3

Test structures for SOA gain and absorption measurement

Semiconductor optical amplifiers are essential building blocks in photonic integration technology. Assessment of their properties is indicative of the quality of fabrication pro- cess and detailed knowledge is important for designing complex active circuits and de- vices. We investigate methods and test-structures for measuring gain and absorption of active materials that are suitable for integrated electrical on-wafer testing. We report measurement results for the Oclaro InP integration platform

Method for polarization-resolved measurement of electroabsorption

\u3cp\u3ePhotonic integrated circuits often use semiconductor components such as amplifiers, detectors, and electroabsorption modulators. For a proper circuit design, it is important to know the absorption spectrum of these semiconductor optical components and how it depends on an applied electric field. We propose a fast and accurate method that uses a compact segmented contact structure to measure the absorption characteristics. The method is based on measuring the transmission of amplified spontaneous emission (ASE) from a single forward-biased section through a varying number of reversely biased absorbing sections. Provided the ASE source emits light in both polarizations, the method measures the absorption spectra for both polarization modes simultaneously, without the need for a polarization filter in the measurement setup.\u3c/p\u3

AWG-based integrated fiber-Bragg-grating interrogator with improved sensitivity

A Fiber Bragg Grating interrogator based on an AWG with custom design of the inputs is described. The proposed modifications ensure a non-zero readout signal on at least two detectors for any wavelength. It is shown that the combined readout allows to track wavelength changes with a resolution better than 5 pm