In an optical device, a slab layer includes an active layer sandwiched between cladding layers. Preferred compositions are those wherein the ingredients are blended into an admixture resulting in a granular product. The techniques are applicable for the integration of all InP-based and GaAs-based single-heterojunction bipolar transistors and double-heterojunction bipolar transistors. The lock pins are secured to the ring, and a spring is arranged between the nut element and the ring to bias the ring and the lock pins towards the lock position. The process is repeated iteratively until some predetermined final stopping criterion is met.