Development of Silicon Photonics Integrated Circuits for Next Generation Optical Access Networks

Various types of data streams such as ultra-high-definition videos and the fifth generation mobile services may require both flexible network management and large capacity of transmission for the optical access networks. Time and Wavelength Division Multiplexing-Passive Optical Network (TWDM-PON) is regarded as a promising candidate for such applications realizing the aggregated bandwidth of 40 Gbps with four wavelength multiplexed 10 Gbps optical signals. Silicon (Si) photonics technology is critical to implement such bi-directional WDM optical transmission functions into a single ultra-compact photonic integrated circuit (PIC) at relatively low cost. The current status of the Si PIC development is reported. The PIC consists of following functional devices; a spot-size convertor for the efficient coupling between a Si waveguide and a single-mode optical fiber, the first WDM filter to separate bi-directional optical signals into up and down-stream signals, the second WDM filter for 100 GHz-wavelength separation, an array of avalanche photodiodes (APDs) for down-stream signal detection, and a modulator to modulate up-stream signals. A semiconductor laser diode die is surface mounted on the PIC. The detail of both device design and experimental results are discussed.