Optical transmitter with millimeter-wave subcarrier

There is increasing need for high-speed fiberoptic links operating in the microwave and millimeter wave range for applications like cellular personal communication systems (PCS), high capacity distribution systems (HDTV, data, interactive multimedia), phased array, remote antennas, etc. The conventional methods of high frequency modulation at millimeter-wave frequencies do not satisfy system requirements like low relative intensity and phase noise, and high dynamic range. They are also costly. Solid-state lasers are well known for their high spectral purity, high optical power output and satisfy the requirements for a high performance optical transmitter for high capacity distribution systems. A compact and mass-producible form of solid state laser is the microchip laser whose short cavity length can lead to high mode-locking frequencies. This thesis concerns the design, fabrication, and characterization of a Neodymium-doped Lithium Niobate (Nd:LiNbO3) mode-locked microchip laser. The 3.48mm long microchip laser radiates at 1.084[mu]m and was mode-locked at 20GHz and 40GHz frequencies. The maximum optical output power was 35mW, and the modulation index of the microwave and millimeter-wave subcarrier was 95.6%. A compatible monolithic Fabry-Perot intensity modulator was also developed to be combined with the microchip laser. With this device the information signal can be superimposed on the millimeter-wave subcarrier. The modulator was designed to withstand high optical power over a wide frequency range (3.1GHz). The entire system provides a compact, low noise, high power optical source with a millimeter-wave subcarrier and a wideband modulator.