Design, Fabrication and Characterization of an InP-Based Tunable Integrated Optical Pulse Shaper

In this paper a tunable integrated semiconductor optical pulse shaper is presented. The device consists of a pair of arrayed waveguide gratings with an array of electrooptical phase modulators in between. It has been fabricated in InP-InGaAsP material for operation at wavelengths around 1.55 mum. Multimode inputs to the waveguide gratings are used to flatten their optical passband. We have used a new short-pulse characterization technique to fully characterize pulse shaping by the device, i.e., both the power and the phase profile. A fourfold decrease in pulse ringing was observed for the devices with flattened passbands. Moreover these devices showed a 25% increase in pulse peak power. The possibilities for using the device as a dispersion (pre-) compensator have been investigated. Pulse reconstruction could be obtained for dispersion values of up to 0.2 ps/nm. The fabrication technology of the pulse shaper is compatible with the fabrication of integrated mode-locked lasers, which makes further integration of complete arbitrary pulse generators possible.