Little Optics Intros Decoders

ANNAPOLIS JUNCTION, Md. -- Little Optics, Inc., an inventor of a patented glass high-index optical waveguide material system, HydexTM, for planar lightwave circuit (PLC) fabrication, announced today the availability of enhanced Differential Phase Shift Key (DPSK) decoder devices. DPSK is emerging as a new transmission format to extend the reach of fiber-optic links relative to conventional on-off key systems. The devices are designed to demodulate phase-coded signals for commercial or defense related applications. Little Optics offers standardized designs ranging from 2.5 GHz to 80 GHz applications.

The DPSK circuit chips fabricated by Little Optics are compact in size (i.e. ~ 1 cm2) and can be integrated with a receiver in a low profile package such as the MSA 300-pin transponder. Moreover, as a large number of chips can be integrated onto a 6-inch wafer, the process can be scaled to support emerging production requirements.

The circuit structure is based on a polarization diverse Mach-Zehnder interferometer . All circuit elements shown are monolithically integrated onto a single chip. The circuits are fabricated such that the delay in the long path arms of the Mach-Zehnder interferometer is equal to 1 bit length. The delay lengths are changed depending on the transmission data rate by "stitching" long path length spirals having a specific delay length using "Pick and Place" stepper lithography strategies. This allows a common bus architecture to be used for any transmission rate.

Little Optics Inc.