1Fiber Radio Using a Mode-Locked Microchip Optical Transmitter — System Considerations and Performance Evaluation

This paper describes the design, assembly, and testing of a prototype fiber-radio communications system that is both low-cost and transparent to common wireless modulation standards. The system architecture employs a mode-locked microchip laser transmitter that simply and efficiently generates all optical signals necessary for fiber-optic transport of millimeter-wave frequencies. This unique architecture eliminates the need for a millimeter-wave local oscillator in the basestation. An emphasis is placed on key subsystem and system-level performance metrics which demonstrate that the fiber-radio link can support demanding high-speed data applications and is compatible with a variety of standard modulation schemes including QPSK, and multi-level QAM. 2I. INTRODCTION There has been much interest recently in fiber-radio or hybrid fiber-optic/wireless systems. These systems utilize high-speed photonic techniques to distribute radio signals over fiber-optic cable to wireless basestations [1]. The radio signals, which may be in the RF, microwave, or millimeter wave (mm-wave) bands, are then used in point-to-poin