THE PROPERTIES OF MOVPE GROWN 1.3 MU-M DFB MQW LASERS INFILLED WITH SEMIINSULATING INP FABRICATED ON SEMIINSULATING SUBSTRATES

The use of optoelectronic integrated circuits (OEICs) is now emerging as a practical technology for a variety of applications, particularly in advanced telecommunications. OEICs consist of a range of devices su ch as lasers, waveguides, modulators, amplifiers, transistors, detecto rs, etc. fabricated on the same substrate. When a semi-insulating subs trate is used, these devices can be electrically isolated by channel e tching, resulting in a low capacitance structure with reduced electric al interference between the subcomponents. One of the devices which is particularly advantageous for this type of integration scheme is the distributed feedback (DFB) laser. The laser can be made to function mo re efficiently by minimizing the current flowing outside the active re gion. This can be achieved by surrounding the active region with semi- insulating iron doped InP. This work describes for the first time, the MOVPE growth, fabrication, and device characterization of 1.3 mu m bu ried heterostructure DFB MQW lasers, which combine the advantages of u sing both a semi-insulating substrate and a semi-insulating infill reg ion in the same device structure. The potential advantage of this desi gn scheme is improved OEIC performance as a result of, reduced capacit ance and electrical crosstalk, enhanced laser output power, higher spe ed, increased efficiency, wider operating temperature and reduced thre shold current. The laser active region consists of 8 x 140 Angstrom qu antum wells of GaInAsP (lambda = 1.3 mu m) and 110 Angstrom barriers o f GaInAsP (lambda = 1.07 mu m). Single mode 1.3 mu m devices of length 250 mu m operating at room temperature produced threshold currents of 8 mA, efficiencies of up to 25%, output powers of 18 mW at 80 mA (pul sed), and a frequency response greater than 12GHz. The parasitic capac itance was estimated to be less than 3 pF.