Photonic Integration

We view Photonic Integration – particularly on indium phosphide (InP) – as a key enabler for many components and modules. Integration enables mass production of, for instance, laser-modulator chips used in very small form factor transceivers such as SFP+ and XFP, as well as the realization of the complex modulation functions needed for 100G and 200G systems. As an example, our integrated modulator chip for the coherent CFP2 includes four parallel Mach-Zehnder modulators, various splitters and recombiners, amplifiers (SOAs), a full suite of inline and dump port detectors for set up and control, and spot size converters on all optical ports to facilitate packaging. This is all achieved monolithically, at the wafer level. The integration process uses precision mass production process tools, including stepper based lithography, to deliver the reproducibility and control essential for these components. The CFP2 100/200G coherent module itself utilizes a trio of InP based PICs, covering the laser, modulation and receiver functions. A critical additional step we have prioritized through integration is to enable almost complete on wafer test of our PICs. We can automatically identify known good die for assembly and map all key parameters at wafer level to maintain process control and integrity. Monolithic Integration is ideally suited to support much higher levels of functionality moving forward, as we progress beyond 200G per carrier into superchannel modules.