High performance analog fiber-optic links for antenna applications

Summary form only given. Simple analytic lumped-element small-signal models have been examined for the two most common link implementations: direct modulation of a diode laser, and external modulation of a laser using a Mach-Zehnder integrated-optic modulator. Although both modulation methods result in an intensity-modulated optical carrier, the modeling reveals that there are fundamental differences between the two in the dependence of various link parameters on device parameters. Analytical and experimental data show that passive impedance matching can be used to reduce loss and even achieve net RF gain in directly modulated links. A similar analysis for externally modulated links shows that the optical power, modulator sensitivity, and impedance matching can be optimized to achieve net gain.<>