Silicon Photonics 
MP is developing a number of novel Silicon Photonics devices and PICs in support of DARPA and Air Force SBIR and STTR programs.  Examples of 2nd generation (all silicon) devices used for TTD in phased array systems are shown opposite.  The photograph below shows the testing of a 20 microring resonator based TTD device, with multi-wedge probes contacting each ring and a ground plane.

A 3rd generation (all silicon) TTD device in a prototype telecom style hermetic butterfly package is shown below - this device includes 24 individually controllable microring resonators (each tuned by a heater), plus a thermoelectric cooler (TEC) and thermistor for control of the device temperature.  The complete device, including polarization maintaining pigtails and electrical connections is shown also on the right - this device was used in early system level measurements to provide TTD in an analog fiber optic system, and to validate the use of MPs TTD devices in high SFDR applications. 

A 4th generation (silicon nitride) commercial grade TTD device with 40 individually controllable microring resonators, in a commercial hermetic package, was first delivered to customers fall 2013.​​  This initial TTD product is described in the Time Delay Devices section.