There's quite a significant difference between an optical computer and a quantum computer.
An optical computer is slightly faster than the traditional CPU architectures.
Our current computers rely on electric circuits to build the basic logic gates (AND, OR, NOT), making use of transistors. The electric circuits pass the data between the transistors (the transistor modifies the signal appropriately, generally outputting a small or little higher voltage that correspond to the values 0 and 1.) An electric current is a flow of electrons, so our current computers are "electron" based.
Optical computers aim to, instead of electrons and electric circuits, use photons for communication (implemented with lasers and optical fiber).
The performance improvement of an optical computer comes from the fact that an electric current flows only at about 10% the speed of light, so about a factor of 10. There's also some other advantages, quoting from wikipedia:
Optical Computing has the main advantages of small size/high density, high speed, low heating of junctions and substrate, dynamically re-configurable, scalable into larger/smaller topologies/networks, well matched for Imaging, massively parallel computing capability and Artificial Intelligence applications i.e.- neural networks of great complexity.
A quantum computer, on the other hand, is a beast. It uses Quantum principles, such as superposition and interference to dramatically improve performance. Generally a quantum computer would make use of qubits which have the nice property of having the value 0, 1 or both. A computer with n qubits, therefore, can be in a superposition of 2^n states, and a single computation on those n qubits (implemented perhaps using electromagnetic signals) would be a computation on the 2^n states.
This means that, in order for a traditional computer to perform the equivalent of one computation by a quantum computer with n qubits, it would need 2^n computations. If n = 1000, in a fraction of a second a quantum computer can perform more computations than there are atoms in the universe.
So, an optical computer provides a linear, constant speedup over a traditional computer while a quantum computer actually allows for an exponential speedup.
