Monolithically integrated 4×4 InGaAsP/InP laser amplifier gate switch arrays

This paper describes the mask layout of a tree-structured strictly nonblocking 4×4 gate switch array. 16 amplifier gates are used in the interconnection region to control the switch state and four booster amplifiers are included just after the inputs and just before the outputs. The switches are fabricated in the InGaAsP/InP material system, and the fabrication process is based on metal-organic vapour-phase epitaxy (MOVPE) and reactive ion etching (RIE) to form the waveguide mesa; selective wet chemical etching is used to define the active sections in the direction of light propagation. Regrowth is performed in two steps by MOVPE: firstly, iron doped semi-insulating and n doped current blocking layers are selectively grown, and secondly, the contact layers are grown. To laterally isolate the active sections from each other, the contact layers outside the contacts are removed by RIE. Antireflective coatings are applied to the cleaved chips to reduce the optical feedback and for improved coupling efficiency