en تخصصي Special كاربردي Applicable We present the procedure for designing a high speed and low power all-optical analog to digital converter (AO-ADC), by integrating InGaAsP semiconductor optical amplifier (SOA) with InP based photonic crystal (PhC) drop filters. The self-phase modulation in the SOA can shift the frequency of the Gaussian input pulse. The two output PhC based drop filters are designed to appropriately code the frequency-shifted analog signals by the SOA, converting them to four desired digital output levels. Our numerical results show that in an appropriately designed AO-ADC, the center wavelength (1572 nm) of an amplitude modulated Gaussian pulse of 1.8 ps width and 1.56 pJ energy can be shifted by 6.7 nm, by the SOA, and then be quantized and coded to four digital levels (00, 01, 10, and 11). The two point-defect PhC drop filters, compensating the effect of the frequency shift by SOA, minimize the AO-ADC integral and differential nonlinearity errors. Semiconductor Optical Amplifier (SOA), Self-Phase Modulation (SPM), Photonic Crystal (PhC), Analog to Digital Converter (ADC). 3 14 http://ijop.ir/browse.php?a_code=A-10-29-4&slc_lang=en&sid=1 Sajjad Moshfe s.moshfe@srbiau.ac.ir 10031947532846003101 10031947532846003101 No Department of Electrical Engineering, Science and research branch, Islamic Azad University, Tehran, Iran Mohammad Kazem Moravvej-Farshi moravvej@modares.ac.i 10031947532846003102 10031947532846003102 Yes Nano Plasmo-Photonic Research Group, Faculty of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, Iran Kambiz Abedi k_abedi@sbu.ac.ir 10031947532846003103 10031947532846003103 No Department of Electrical and Computer Engineering, Shahid Beheshti University, Tehran, Iran