We have fabricated a laser array module using a passive self-aligned flip-chip bonding technique. Silicon optical bench was used as a submount with PbSn (Tm=183¢J) solder bump and V-grooves. A 4-channel laser array was flip-chip mounted with coupling efficiency of 56% to cleaved 62.5/125£gm multimode fiber ribbons. The optimum fabrication parameters were bonding time of 20 seconds and bonding load of 10g. The average misalignments were measured to be 1£gm and 5£gm for X and Y directions , respectively.

Distributed Feedback (DFB) lasers and integrated laser arrays are of great importance in Wavelength-Division Multiplexing (WDM) systems in fiber optic communication systems. High-performance, low-cost DFB lasers and laser arrays are highly desirable for applications in intra-datacenter transport and in local access networks. This dissertation is focused on the design, fabrication and achievement of high-performance, low-cost DFB Lasers and Integrated DFB Arrays for WDM Systems. It investigates the use of a novel sampled grating approach, called the equivalent phase shift method, to achieve integrated DFB laser arrays with single-mode lasing at uniformly-spaced and precisely-positioned wavelengths. First, laterally-Coupled DFB (LC-DFB) lasers with first-order sidewall gratings are realized, with gratings fabricated by optical interference lithography instead of e-beam. Then, LC-DFB lasers and LC-DFB laser arrays with sampled gratings and equivalent phase shifts are proposed, numerically analyzed and experimentally demonstrated. Each LC-DFB laser with an equivalent quarter-wave phase shift is shown to lase at the pre-specified wavelength in a single longitudinal mode, with good side-mode suppression ratio (SMSR) over a very wide range of injection currents. Integrated LC-DFB laser arrays with five uniformly-spaced wavelength channels are demonstrated, in close agreement with the design. For better performance, buried heterostructure (BH)-DFB laser and laser arrays are also demonstrated using the same sampled-grating technology. A 6-wavelenth laser array with a 300 μm cavity length and a 8-wavelength laser array with 250 μm cavity length are successively demonstrated, each showing precisely positioned lasing wavelengths, good SMSR, and uniformly good lasing characteristics under a wide range of operating currents and temperatures. Finally, it is demonstrated that the wavelength of a monolithic WDM laser array can be continuously tuned over a very wide wavelength range of nearly 40 nm. The proposed method offers a practical and cost-effective solution for the manufacture of high-performance, monolithic multi-wavelength DFB laser arrays as well as widely wavelength-tunable DFB lasers for integrated WDM systems.

Several novel techniques for controlling, managing and utilizing high power diode lasers are described. Low pressure water spray cooling for a high heat flux system is developed and proven to be an ideal cooling method for high power diode laser arrays. In order to enable better thermal and optical performance of diode laser arrays, a new and simple optical element, the beam control prism, is invented. It provides the ability to accomplish beam shaping and beam tilting at the same time. Several low thermal resistance diode packaging designs using beam control prisms are proposed, studied and produced. Two pump cavity designs using a diode laser array to uniformly pump rod shape gain media are also investigated.