Although there are many positive aspetcs about optical computers, there are also some disadvantages.
Parts for conventional computers are produced in plants whose only job is to manufacture these parts therefore, the price is low mainly do to mass production. Optical components on the other hand there are not any manufacturers the specialize in the production of optical components and as a result, the price is high.
Components are not the "right size"
In contrast with conventional computer parts, optical components are of larger magnitude. Researchers have not yet been able to create optical components small enough to assemble a motherboard.
For the computer to work properly, the miniaturized components need to be manufactured exactly. As aforementionned, this has not yet been achieved. Even the slightest of deviations can cause the light beams (lasers) to divert resulting in massive problems. Therefore, it can be concluded that the production process is quite costly.
Conventional computers are assembled accordingly with the Von Neumann archictecture. Application software and operating systems are built around this architecture. In contrast, optical computers are put together according to a different architecture because of the system's parallelism. As a result, opearating systems such as Microsoft Windows may not be able to function properly or may not even function at all.