High performance polarization insensitive electroabsorption modulator based on strained GaInAs–AlInAs multiple quantum wells

Abstract

We report on the polarization independent operation of an electroabsorption guided-wave modulator based on strained GaInAs–AlInAs multiquantum well structure. The device operates in the 1.5–1.6 μm wavelength range and exhibits very high static performances as illustrated by the measured 15 dB/100 μm extinction ratio for a drive voltage of only 1.25 V. We show that the observed polarization insensitivity of this device is in good agreement with the calculation of the electroabsorption curves. The detailed analysis indicates that significant improvement of the performance is still possible.

Bandgap engineering of electro-optical modulators and switches

“…Polarization insensitivity is not an exact result, but stems from a quasi perfect compensation of different contributions. Note that these theoretical results are in close agreement with recent experimental findings in the GaInAs-InP [9] and GaInAs-AlInAs [10] families of materials. Clearly, this detailed modelling and its comparison with experiments opens the way for the final optimization of these devices.…”

Chirp dependence in InGaAs/InAlAs multiple quantum well electro-absorptive modulators near polarization-independent conditions

“…The optimization of the ternary InGaAs/InAlAs MQW structure for use in these devices has drawn much attention from several researchers. [2][3][4] Polarization insensitivity can be reached in a QW when the heavy-and light-hole energies are degenerate. 5 This occurs in an InGaAs/InAlAs MQW structure at a certain well width (w) and for gallium concentration (x) pairs for which the heavy-and light-hole energy splitting (⌬s) equals zero.…”

“…1 as close as possible to this curve. [2][3][4] The chirp parameter (␣ L ) translates the wavelength broadening of the linewidth of light traveling through the device caused by the unavoidable change in the refractive index due to the applied electric field. Understanding the behavior of ␣ L near the polarization independence region is vital for optimization of the modulator.…”

AnomalousIversusVcharacteristics of InGaAs/InAlAs strained multiple quantum well structures for amplitude modulators

“…External modulators based on III-V semiconductors, which operate at 1.55 µm, have been extensively studied [1][2][3]. In particular, the amplitude modulators fabricated with strained InGaAs/InAlAs multiple quantum well structures (MQW) are of great interest [3][4][5][6]. In order to satisfy the recent demands for telecommunication systems it is desirable that such a device be polarization insensitive, chirp-free, integrable, driven by low voltages and it should present a high contrast ratio (CR).…”