ACHIEVING BROAD-AREA LASER-DIODES WITH HIGH-OUTPUT POWER AND SINGLE-LOBED FAR-FIELD PATTERNS IN THE LATERAL DIRECTION BY LOADING A MODAL REFLECTOR

A modal reflector, which consists of a high-reflectivity region surrou nded by low-reflectivity regions, is added to the front facet of two t ypes of broad-area laser diodes (LD's) to control the lateral modes. O ne type of LD is the self-aligned laser with a bent active layer (SBA LD) that has a real index-guiding mechanism. The other is a planar-str ipe LD that consists of a Zn-diffused region to confine the current fl ow and has a gain-guiding mechanism. For the SBA LD's with a modal ref lector, stable single-lobed far-field patterns (FFP's) are obtained at up to 03 and 0.4 W output powers in continuous wave (CW) operation an d pulsed operation, respectively. In addition, for planar-stripe LD's with a modal reflector, stable single-lobed FFP's are obtained at up t o 0.4 W in CW operation. The lateral modes inside the cavity are analy zed by utilizing a slit model and FFP's are calculated. Good agreement is found between experimental and calculated FFP's for a large Fresne l number.