Design of Reconfigurable All-Optical Half-Adder and Half-Subtractor Using Highly Non-Linear Fiber

This paper proposed all-optical half-adder and half subtractor based on cross-phase modulation in highly nonlinear fiber placed in Mach-Zehnder interferometric configuration. Reconfigurable half-adder and half-subtractor have been implemented employing two laser sources as carrier and two MZI structures with HNLF of length 200 m with effective area 15
$\mu \mathrm{m}^{2}$
is utilized in both parallelly placed upper and lower arms of MZI-1 and MZI-2. The phase shifter employed at MZI-2 is deciding factor whether the circuit acts as half adder or half subtractor. The emphasis is done to achieve high bit rate of 180 Gbps and better Q-factor of greater than 20 dB in design and realization of half adder and half subtractor. The performance of parameters is evaluated on the basis of output quality factor (Q-factor) and output extinction ratio. The implementation results of the design show that the minimum Q-factor for sum and carry output of half adder and difference and borrow of half subtractor is 27 dB. The extinction ratio of the sum and carry output achieved is greater than 19 dB. The extinction ratio of difference and borrow output achieved is greater than 15 dB. In future, such circuits can be used to realize the all-optical signal processing devices and all-optical transmission.