Researcher(s)
- Nora Charles, Electrical Engineering, University of Delaware
- Giana Pennisi, Computer Engineering, University of Delaware
Faculty Mentor(s)
- Vishal Saxena, Electrical and Computer Engineering, University of Delaware
Abstract
Silicon photonics has gained prominence for faster communication as the need for low-cost, low-loss, and high-bandwidth data links grows. While all the signal processing occurs on a silicon-based photonic integrated circuit (PIC), the optical input-output (IO) interfaces are realized using optical fiber arrays. While using fiber arrays, coupling light into a silicon chip, while tedious as most on-chip silicon waveguides are around 220nm x500nm in cross-section, is achievable. Proper edge alignment between the edge couplers on the chip and the fiber array is vital to couple light in and out of the chip correctly. This requires automation of the experimental setup using precision stages, controllers, and optical microscopes. With a Thorlabs NanoMAX stage, we have six ranges of motion (x-optical, y-lateral, z-vertical, roll, pitch, and yaw) to finely align the chip with the fiber array.
On-chip loopbacks assist the PIC-to- fiber array alignment process. If the light source, i.e., a tunable laser, does pass through the chip correctly, the returned light is detected at the optical power meter (or detector). The stage scans in x,y (and z) directions using precise stepper motors with manual tuning or software automation. The scan heat map of the detected power indicates the presence and quality of the alignment. We need to maximize the returned power by optimizing the distance between the PIC and fiber array while ensuring the best possible mode coupling. Automated edge coupling is an ideal method for testing P.I.C.s, where the setup time, repeatability, and robustness are paramount. This experimental setup allows the testing of various PICs intended for optical communication links and radio frequency photonics. This experimental setup provides innovative ways of expanding the field of photonics improving integrated circuits to produce more high-speed and precise technology.