Column Address Selection in Optical RAMs With Positive and Negative Logic Row Access

An optical RAM row access gate followed by a column address selector for wavelength-division-multiplexing (WDM)-formatted words employing a single semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) is presented. RAM row access is performed by the SOA-MZI that grants random access to a 4-bit WDM-formatted optical word employing multiwavelength cross-phase-modulation (XPM) phenomena, whereas column decoding is carried out in a completely passive way using arrayed waveguide grating. Proof-of-concept experimental verification for both positive and negative logic access is demonstrated for 4 × 10 Gb/s optical words, showing error-free operation with only 0.4-dB-peak-power penalty and requiring a power value of 25 mW/Gb/s.