UC San Diego

Data centers are heavily dependent upon transceivers for the exchange of data. This work analyzes various components of a transceiver ((de-)multiplexer, modulator, and laser) and evaluates how to exchange or enhance performance by incorporating Bragg based structures. First, it is shown an apodized 4-port contra-directional coupler can perform wavelength division multiplexing (WDM) at O-band wavelengths in a semi-dense channel grid. The devices are concatenated to create a 16-channel system where normally a 4-channel system is utilized. The concept of WDM is extended to mode division multiplexing, where the orthogonal spatial modes of a waveguide are excited and controlled. It is demonstrated Bragg devices can excite the TE01 mode while also controlling it in a resonant format. Next, the apodized 4-port structure is used to demonstrate an arbitrary and tunable spectral shaping device. By showcasing a wide array of intuitive spectral building blocks it is shown that multiple functions, such as WDM or modulation, can be achieved with a single device. Finally, a laser is created by coupling a reflective semiconductor optical amplifier (RSOA) to a Bragg based structure. The Bragg structure completes the laser cavity by operating as a mirror and can be tuned in wavelength and in intensity, where the latter has a GHz response time. Combining these devices suggests a transceiver can largely be composed of Bragg based structures, which has the potential to simplify the design of future transceivers.