Minimalist-design, high-functionality, micro-ring resonator-based optical filter with narrow linewidth and low group delay using Looped Back Over- and Under-coupled Resonator (LOBOUR)

Abstract

We present a minimalist design but high functionality micro-ring resonator based optical filter with narrow linewidth and low group delay using a novel design we called LOBOUR for LOoped-Back Over-and UnderCoupled Resonator (LOBOUR). The characteristics of both narrow linewidth and low group delay (low chromatic dispersion) generally do not come together especially when using a single ring resonator. The Cascaded Over-and Under-Coupled Resonator (COUR) design was able to achieve this goal but introduced many practical fabrication issues. Here, we present an alternative design to COUR which uses only one ring resonator and without fabrication and manufacturing issues. It can achieve 50 dB extinction ratio and tens of ps performance. We also present important parameter selection mapping for LOBOUR.

Adaptive High Linearity Intensity Modulator for Advanced Microwave Photonic Links

“…Accordingly, the corresponding phase response, Θ MRR and group-delay (GD) [95] response of MRR can be derived as [110,111]:…”

“…(14) and (16) will be handy in the analysis of the new modulator that we discuss in Section 4. The relationship between the magnitude of the bus waveguide-to-MRR transmission coupling coefficient (τ) and the RR waveguide loss factor (α) defines the three different coupling conditions of MRR [73,85,91,[110][111][112]. Figure 10(a) shows the typical MRR while Figure 10(b) depicts its three different operating coupling conditions known as (1) critical-coupled (CC) when α = τ, (2) over-coupled (OC) when α>τ, and (3) under-coupled (UC)whenα<τ.…”