Future thermonuclear fusion reactors need remote-handled equipment for maintenance tasks, since the stringent environmental conditions prohibit direct human interventions. Fiber-optic technology is considered since many years as a potential reliable alternative to conventional electronic transmission lines. Recently we demonstrated the feasibility of transmitting analog data with a hybrid opto-electronic link at 850 nm, up to total doses of several MGy. However, for bidirectional communications under these severe conditions, we still need to characterize the corresponding photo detector response and design an adapted radiation tolerant amplifier. We therefore assessed in-situ the radiation response of commercially available p-i-n type Si-detectors, at a constant temperature of about 60°C, first under gammas rays up to a total dose of about 10 MGy and under neutrons up to a fluence of about 7•1015/cm2. We also performed similar tests with InGaAs photodiodes at different wavelengths, in order to assess their use in radiation tolerant coarse wavelength division multiplexing (CWDM) transmission architectures. Our results indicate that the wavelength dependence of the detectors' response under gamma radiation remains almost unchanged. We observed no catastrophic failure for these InGaAs devices, nor for the Si devices up to 10 MGy. The increase of the dark current is the most obvious radiation effect, particularly under neutrons. In this paper we also present temperature dependent measurements and hence assess to what extend both ionizing and particle radiation affect the photodiodes reliability.