The design for an all optical XOR gate is proposed. The basic idea is to split the input beams and let them cancel or strengthen each other selectively or flip the encoded information based on their polarization properties. The information is encoded in terms of polarization of the beam. Polarization of a light beam is well understood hence the design should be feasible to implement. The truth table of the optical circuit is worked out and compared with the expected truth table. Then it is demonstrated that the design complies with the linear behavior of the XOR function. In the next section, based on a similar idea, the design of an all optical CNOT gate is proposed. The truth table for the gate is verified. Then, it is discussed how this approach can be used for Linear Optics Quantum Computation (LOQC). It is shown that with a Hadamard gate and a rotation gate, the CNOT gate makes up a universal set of quantum gates based on linear optics. This novel approach requires no additional power supply, extra input beam or ancilla photon to operate. It also doesn't require the expensive and complex single photon source and detector. Only narrowband laser sources are required to operate these gates.

Date Published: 8 May 2012
PDF: 14 pages
Proc. SPIE 8400, Quantum Information and Computation X, 84000N (8 May 2012); doi: 10.1117/12.918894

Published in SPIE Proceedings Vol. 8400:
Quantum Information and Computation X
Eric Donkor; Andrew R. Pirich; Howard E. Brandt, Editor(s)