Recently, Vertical Cavity Surface Emitting Laser (VCSEL) has become an important aspect in optical communications and optical signal processing because of its great advantages. These advantages are enhanced when this device is used with external Optical Injection Locking (OIL). In this thesis, a comprehensive study of static and dynamic characteristics of optical injection locked VCSEL are presented. The analysis is based on the solution of the laser rate equations in both static and small_ signal dynamic regimes. The analysis takes into account the effect of various noise terms in the absence and presence of OIL. The analysis yields analytical expressions to describe _ Effect of cavity dimensions, facet mirrors ( R R R . = 2 1 ), and number of quantum wells (NQW) in the laser active region on the threshold current ( ) and output power ( ). thr I out P _ Effect of injection efficiency ( inj ç ), and laser linewidth enhancement factor ( T) on frequency locking range ( F ¢ ) and wavelength locking range ( ). ¢ë _ Discuss the spectrum of the Relative Intensity Noise (RIN). The results are presented for a 1550 nm, Multi Quantum Well (MQW) Ga0.43 In0.57 As0.92 P0.08 active region for VCSEL to assess the effect of various structure parameters on the static and (RIN) characteristics of the injected locked laser. The results indicate clearly that the RIN decreases in the presence of OIL. All the results reported in this work are computed using MATLAB 7.