Suppressing electroabsorption with intra-step-barrier quantum wells for high-power electroabsorption modulators

High-Power Intrastep Quantum Well Electroabsorption Modulator Using Single-Sided Large Optical Cavity Waveguide

“…Due to the characteristics of IQW, electroabsorption at small reverse bias ( 3.2 V, in this case) is suppressed [6]. At a large enough bias ( 3.2 V), a large absorption occurs.…”

“…2. The slight blue shift at low field is characteristic of IQW [2], [6]. At field 60 kV/cm, the QCSE becomes dominant and the exciton resonance is redshifted and broadened.…”

“…The IQW has the additional merit of large quantum confined Stark effect (QCSE) [3]- [5], which implies small drive voltage. Our previous IQW EAM was limited by the available materials and the waveguide design that resulted in devices with a large optical insertion loss of 20 dB [6].…”

“…At field 60 kV/cm, the QCSE becomes dominant and the exciton resonance is redshifted and broadened. IQW EAM can handle high power because the large electroabsorption occurs at a higher electric field [6]. Above the IQW layer is a separate electric field confinement layer, consisted of undoped 50-nm InGaAsP and 50-nm InP, for reducing the valence band offset between the p-InP and IQW absorption layer that can block the swept-out of photogenerated holes.…”

Chirp Parameter of Electroabsorption Modulators with InGaAsP Intrastep Quantum Wells

“…One of the approaches proposed recently is utilizing the intrastep quantum wells (IQWs) as an EA medium. [4][5][6][7] The effect of the added step barrier inside the square quantum well (QW) in the IQW has been theoretically analyzed and experimentally demonstrated to delay the EA effect to a higher electric field. 5,6) Therefore, the IQW EAM can be operated at a higher operation voltage without sacrificing the modulation efficiency.…”