Programmable photonics : an opportunity for an accessible large-volume PIC ecosystem

We look at the opportunities presented by the new concepts of generic programmable photonic integrated circuits (PIC) to deploy photonics on a larger scale. Programmable PICs consist of waveguide meshes of tunable couplers and phase shifters that can be reconfigured in software to define diverse functions and arbitrary connectivity between the input and output ports. Off-the-shelf programmable PICs can dramatically shorten the development time and deployment costs of new photonic products, as they bypass the design-fabrication cycle of a custom PIC. These chips, which actually consist of an entire technology stack of photonics, electronics packaging and software, can potentially be manufactured cheaper and in larger volumes than application-specific PICs. We look into the technology requirements of these generic programmable PICs and discuss the economy of scale. Finally, we make a qualitative analysis of the possible application spaces where generic programmable PICs can play an enabling role, especially to companies who do not have an in-depth background in PIC technology

Building graph-based programming strategies for reconfigurable photonic circuits

We have developed a graph representation of programmable photonic mesh circuits that can be used by pathfinding algorithms. We modified the Dijkstra algorithm to observe only physically possible connections in the graph, demonstrating flexible rerouting in case of node malfunction

An equivalent circuit model of the traveling wave electrode for carrier-depletion-based silicon optical modulators

We propose an equivalent circuit model for the coplanar waveguide (CPW) which serves as the traveling wave electrode to drive carrier-depletion-based silicon modulators. Conformal mapping and partial capacitance techniques are employed to calculate each element of the circuit. The validity of the model is confirmed by the comparison with both finite-element simulation and experimental result. With the model, we calculate the modulation bandwidth for different CPW dimensions and termination impedances. A 3 dB modulation bandwidth of 15 GHz is demonstrated with a traveling wave electrode of 3 mm. The calculation indicates that, by utilizing a traveling wave electrode of 2 mm, we can obtain a 3 dB modulation bandwidth of 28 GHz

A simple and novel method to obtain an FSR free silicon ring resonator

A simple and novel method to make a silicon ring resonator without the limit of free spectral range (FSR) is presented. For many applications, a ring resonator is desired with an ultra-wide FSR, a high quality factor, a large extinction ratio and low-fabrication complexity. In this paper we propose a novel method to obtain such a ring resonator, which is a single all-silicon micro-ring with a FSR as large as 150 nm around 1550 nm. It's based on the well-known phenomenon of resonance splitting

Discretization effects of digital control of thermally tunable 2x2 MZI couplers

We describe how digital voltage driving of tunable 2×2 Mach-Zehnder couplers with thermo-optic phase shifters introduces discretization errors which significantly affect programmable photonic circuits. Performing quantitative analysis, we show that proper biasing of couplers and simultaneous driving of arms can improve discretization errors