Lightwave links for analog signal transfer are being developed and evaluated for application in high-density interconnects. The reflective links are based on compact electrooptic intensity modulators connected by ribbons of single-mode fibers to remotely located transceivers (lasers and photoreceivers) and read-out electronics. For long term characterization, four asymmetric Fabry-Perot modulator (AFPM) prototypes have been continuously operated and monitored during a period of eight months. The collected data allow evaluation of the system time stability and simulation of the possible recalibration procedures. The recalibration requirements to achieve the desirable accuracy and reliability are inferred statistically.