Fully integrated 3-bit all-optical analog to digital converter based on photonic crystal semiconductor optical amplifier

Integrating a photonic crystal based semiconductor optical amplifier (PhC-SOA) composed of InP/InGaAsP/InP heterostructure with eight PhC based channel drop filters (CDFs) based on an InGaAsP platform, we have designed a fully integrated all-optical 3-bit analog to digital converter (AO-ADC). A probe signal after passing through a 9-mu m long PhC-SOA in the presence of an amplitude-modulated Gaussian pulse of 1.422 ps width and maximum energy of 37.2 fJ exhibited a 4.8-nm wavelength shift. The eight appropriately designed PhC-CDFs have coded the chirped signal into eight quantization levels. The numerical results show that the proposed structure can convert analog photonic signals into 3-bit digital output with no missing code at 10Gs/s. The proposed AO-ADC structure with a small footprint of 455 mu m(2), along with its ultra-low power consumption, can pave the way for the further development of the next-generation integrated photonic chips.