10-GHz All-Optical Gate Based on a III–V/SOI Microdisk

Abstract

Abstract-We demonstrate an ultra-fast and low power all-optical gate in pump-probe configuration based on free carrier induced refractive index modulation in a 5µm radius InP/InGaAsP microdisk heterogeneously integrated onto an SOI waveguide circuit. High speed gating is obtained by extracting the carriers from the microdisk active layer by applying a reverse bias. Measured transient responses show that this gate is capable of working up to 20GHz.Index Terms-Microdisk, Optical gate, SOI.

Ultrafast and bias-free all-optical wavelength conversion using III-V-on-silicon technology

“…The fast switch-off time is due to fast recombination of free carriers owing to the high surface to volume ratio and rough side walls of the microdisk. Use of smaller diameter (7.5µm) of the microdisk here as compared to that in our previous work (10µm) [6] has contribution in faster switch-off time but at the same time we believe that the probe beam also acts as a seeding beam and contributes for faster response. It is observed that the extinction ratio increases with increasing pump power but the switch-off time also becomes larger.…”

“…So far ultra-fast (of the order of 10 Gbps) alloptical switching, modulation and wavelength conversion in microrings/disks on the SOI platform has been demonstrated using reverse bias [2], ion implantation [4] and forward bias [5]. Realization of bias-free on-chip alloptical functions results in easy packaging of the chips due to the reduced number of pins required.In our previous work [6] we demonstrated 10GHz alloptical gating in a 10 µm diameter III-V/SOI disk but the use of reverse bias was necessary to achieve this speed and the extinction ratio was only 4.5dB. Using the same concept as in ref.…”

“…In our previous work [6] we demonstrated 10GHz alloptical gating in a 10 µm diameter III-V/SOI disk but the use of reverse bias was necessary to achieve this speed and the extinction ratio was only 4.5dB. Using the same concept as in ref.…”

“…Using the same concept as in ref. [6], here we report on all-optical wavelength conversion of a non-return to zero (NRZ) onoff keyed (OOK) pseudo-random bit sequence (PRBS) data signal at the speed of 10Gbps in a 7.5µm diameter III-V(InGaAsP-InP)/SOI microdisk. The microdisks are fully fabricated in a CMOS pilot line.…”

“…With 12dB change in the power, the blue shift is completely cancelled by the red shift and the red shift dominates for further power increase. Next, dynamic measurements were performed for all-optical gating in a pump-probe [6] configuration keeping the probe wavelength around the longer wavelength resonance and nearly critically coupled. The reason to choose the higher wavelength resonance as a probe is that it has a higher static extinction ratio as compared to that of the shorter resonance wavelength and will give higher extinction ratio in the output.…”