Abstract: The steady and transient characteristics of micro-cavity lasers were analyzed using rate equations. It is proved that the carry accumulation and laser output will be strengthened, in spontaneous emission enhancement micro-cavity lasers. Modulated by a step current, the spontaneous emission enhancement would weaken or eliminate relaxation oscillation and improve response frequency of the lasers. It is learnt that the area of the eye diagram would enlarge with spontaneous emission increasing, which would open vast vistas in optical connection. Also, the fiber communication with the laser as light resource was simulated. The received eye diagram, after 10 Gbit/snumerical coding translate 60 kilometers is given.