40 Gb/s AlGaInAs Electroabsorption Modulated Laser Module Based on Identical Epitaxial Layer Scheme

Abstract

A 40 Gb/s transmitter module containing an AlGaInAs electroabsorption (EA) modulator monolithically integrated with a distributed feedback (DFB) semiconductor laser has been fabricated using identical epitaxial layer (IEL) approach. Low loss coaxial-to-coplanar waveguide (CPW) transition is designed and fabricated for the module. By improving the quality of the anti-reflection (AR) coating on the EA modulator facet and optimizing the structure of the CPW transmission line, resonances in the frequency response of the module have been effectively suppressed. The module exhibits a small signal modulation bandwidth over 35 GHz, and clear eye opening has been demonstrated under 40 Gb/s nonreturn-to-zero (NRZ) code modulation.

Resonance Suppression of Grounded Coplanar Waveguide in Submount for 40 Gb/s Optoelectronic Modules

“…The submount is packaged into a metal housing structure and connected to a coaxial K-connector. A series of resonances occur in the measured small signal response and microwave reflection, as reported in our previous report [4].…”

“…Such resonances are detrimental to the performance of high-speed optoelectronic devices and must be eliminated in practical applications. Recently, our group reported a 40 Gb/s electroabsorption modulated laser (EML) module, in which parallel-plate mode induced resonances are suppressed by optimizing solder connection between top and bottom grounds of the GCPW [4]. However, as the resonance frequency is sensitive to the length of the solder connection, critical adjustment is required to suppress the resonances.…”

40 Gb/s InGaAlAs EML module based on identical epitaxial layer integration scheme

“…Both the amplitude and the frequency of the resonances remain relative stable regardless of the modulator bias and the laser current. The resonances above 15 GHz are attributed to the parallel-plate mode propagating through the CPW transmission line on the submount [13]. The metal support at the back of the CPW transmission line makes it actually a grounded CPW (GCPW) structure, which is known to be vulnerable to resonances due to parallel-plate modes supported by the top and bottom ground electrodes [14].…”

Electroabsorption modulator laser for cost-effective 40 Gbit/s networks with low drive voltage, chirp and temperature dependence

“…40 Gbit/s Ethernet seems the upgrade of choice to meet this demand [1]. Electroabsorption modulator lasers (EMLs) have recently attracted much attention [2][3][4][5][6] as they combine the low-drive voltage characteristics of a directly modulated laser (DML) and the low-chirp features of lithium niobate modulators, which will minimise power consumption and footprint, while optimising cost.…”