Lightwave Magazine recently reported that Optical interfaces on a Silicon chip (referred to as CMOS Photonics) are staring to see reality in the lab. With CMOS photonics all of the optical and electronic components needed to build an optical transceiver are built onto a CMOS die. The photonic elements on the chip communicate with each other via optical waveguides etched directly on the die. these waveguides operate right next to and simultaneously with the electrical connections etched into the die.

One of the largest challenges in creating CMOS photonic chips has been getting the optical signal on and off the chip. Traditionally, the optical signal is coupled off the edge of the die. However, to accomplish this, each die needs an edge polish and an antireflective coating on the sidewall. Unfortunately, this approach has not provided a good yield of working components.

Newer rese3arch is focusing on (no pun intended) the use of holographic lens’ to couple the light on/off the die. The lens is used to focus the light coming off the die directly into the fiber with as little loss as possible. The picture below shows a dual XFP module on a single Silicon Die

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