title: Dynamic response of modulators based on cascaded-ring-resonator.
abstract: We investigated the dynamic response of a cascaded-ring-resonator-loaded Mach-Zehnder modulator (CRR-MZM), in which a number of cascaded ring resonators (RRs) are loaded in the interferometer as phase modulators. The analytical form is derived for the small-signal response of CRR-MZM using temporal-coupled-mode (TCM) theory, and its validity is confirmed by numerical calculations. It is revealed that the bandwidth of the CRR-MZM is maximized by setting proper delays in driving signals between neighboring RRs; the optimized delay is twice the photon lifetime of each RR. The calculated performances of CRR-MZMs are compared with those of standard modulators based on a single-ring-resonator (SRR) without interferometer, in terms of the modulation depth and bandwidth. For a given degree of the refractive index change in a waveguide, CRR-MZM can provide a larger modulation depth than a SRR-type modulator in frequency ranges exceeding 25 GHz.
authors.affiliation: Fujitsu Laboratories Ltd. 10-1 Morinosato-Wakamiya, 243-0122, Japan. akiyama.suguru@jp.fujitsu.com
authors.forename: Suguru
authors.initials: S
authors.lastname: Akiyama
authors.forename: Shintaro
authors.initials: S
authors.lastname: Nomura
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007368:Interferometry / Q000295:instrumentation*; D008872:Microwaves; D055096:Optical Devices; D012031:Refractometry / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*