Response shaping with a silicon ring resonator via double injection

Modern systems often provide complex functionality that can be realized by tailoring together elements of simpler functionality. Multiplicity of simple optical functions (response shapes), when densely fabricated on a chip, can promote the concept of a field-programmable optical array. Shaping of the frequency response, or otherwise an electrical-to-optical response, is studied and demonstrated by means of a racetrack-shaped ring resonator designed and fabricated in the so-called double injection configuration. This configuration possesses a unique property that allows two free spectral range states (regular, 2 × regular) to exist for a single ring length. Shaping is realized by properly selecting different coupling coefficients that provide a variety of interesting responses. Here, we demonstrate various shapes including: sinusoidal, triangular (linear), square (bandpass), dips and peaks (two states), spikes (tangent-like), interleaver and a so-called 20dB-min parameters-insensitive-response modulator. The transmission responses were experimentally realized, fabricated in a silicon-on-insulator platform and characterized at wavelengths around 1,550 nm.