A self-contained module injects seeds into a slave laser for applications such as single mode or multimode injection seeding, master oscillator power amplifiers, regenerative amplifiers, optical parametric oscillators, Raman lasers, and LIDAR systems. The injection source provides a continuous wavelength sweeping for master-slave resonance to replace conventional cavity length control of the slave laser and phase locking schemes. The inventive module can be operated remotely as a separate unit or be packaged as a subsystem in the injection seeding system. The salve can be used as it is. Modifications of the slave laser and/or additional efforts are not needed.