The OCCT-3442-1 from L3 Narda-MITEQ is a Fiber Optic Transmitter with Bandwidth 3.4 to 4.2 GHz, RF Input Power -15 to 5 dBm, Wavelength Range 1540 to 1560 nm, Output Optical Power 4 mW, Spectral Width 1 nm. More details for OCCT-3442-1 can be seen below.