Me whakamahi tahi nga pūoko muka (Ma te whakaata i te kurupae, te whakaata huritao) me te whakakorikori muka.
Ko te pūoko muka whatu he pūoko ka huri i te āhua o te mea ine hei tohu whatu ine. Ko te kaupapa mahi o te pukoro muka whatu ko te tuku i te kurupae mai i te puna marama i roto i te muka whatu ki roto i te modulator, te taunekeneke i waenga i te modulator me nga tawhā ine i waho o te modulator, kia taea ai e nga ahuatanga whatu o te marama penei te kaha o te marama, te roangaru, te auau, te wahanga, te ahua polarization, me era atu, ka huri hei tohu whatu whakahuri, katahi ka puta mai i te muka whatu ki roto i te tawhā photoelectric. I roto i te tukanga katoa, ka whakaurua te kurupae marama i roto i te muka whatu, a ka tuku i roto i te modulator, i roto i nei te mahi o te muka whatu te tuatahi ki te tuku i te kurupae marama, whai muri i te mahi o te modulator marama.