High-power reliable aluminum-free lasers

zyxwvutsrq zyxwvutsrqp zyx - 3:30pm 4:00pm (Invited) WY 1 HIGH-POWER RELIABLE ALUMINUM-FREE LASERS M. Pessa*, P. Savolainen*, M. Toivonen*, M. Jalonen*, A. Salokatve*, J. Aarik+, A. Ovtchinnikov+,K. Rakennus', R. Murison", M. Jansen", R. Nabiev", and F. Fang" *TampereUniversity of Technology, P.O. Box 692,33 101 Tampere, Finland Telephone +358 3 3652111, Fax +358 3 3652600 +CoherentTutcore Ltd., P.O. Box 48,33721 Tampere, Finland Telephone +358 3 3161485, Fax +358 3 3184544 "EG&G, Optoelectronics Division, 2200 1 Dumbeny, Vaudreuil, Quebec, Canada J7V 8P7, Telephone +1514 424 3375, Fax +1514 4243413 "Coherent Inc., Laser Group, 5 100 Patrick Henry Drive, Santa Clara, Ca 95056-0980 Telephone +1408 7644000, Fax +1408 7644329 Summary Aluminum-free laser diodes emitting at wavelengths fiom 800 to 1,100 nm, prepared by metal-organic chemical vapor deposition, gas-source molecular beam epitaxy, and allsolid-source molecular beam epitaxy (SS-MBE), are a debated issue. The main question is the lifetime performance that is not yet explored well enough, owing to the lack of availability of these lasers. The potential advantages of Al-free lasers over their Al-bearing counterparts have been widely discussed. GaInP replacing GaAlAs in the cladding layer has good electrical and thermal conductivity. Its non-radiative surface recombination velocity is comparatively low. The concentration of donor related deep levels is small, and the unpassivated mirror facets are not easily oxidized. The comer stone of the Al-free technology is the 980-nm laser' developed for pumping light into Er-doped optical fiber amplifiers. Its short-term reliability is shown to be excellent, as deduced from thermal roll-over tests. Long-term reliability is also impressive. Ongoing life tests at 25 "C have accumulated 700,000 device-hours to date at output levels of 100, 150, and 200 mW (Fig. 1). They exhibit an overall picture of little or no significant degradation, no correlation with the output power used, and not a single sudden unexpected failure during 2.5 years of life test. The 808-nm laser as a pump source for Nd:YAG and Nd:YV03 solid-state-lasers is another important application. High output power of 100 W under cw operation from a 1 cm Al-free laser bars (with fill factor of 30 %) and over 5 W from a single 150-pm This Al-free material wide stripe laser grown by SS-MBE have been shows excellent uniformity of laser characteristics across the wafer, which results in high yield of devices. Adding A1 in the cladding layer of an Al-free-active-region 808-nm laser has yielded encouraging results, notably, increased To up to 140 The aging tests of laser bars grown by SS-MBE are under way. zyxwvu zyx zyxw 0-7R03-3895-2/97/$10.00 01997 IEEE 195 zyxw zyx zyxw 980nm Life Test 100/150/20OmW@ 25°C zyxwvutsrqp 4 w l l t *E 300 200 t Hours On Test zyxw zyxw M. Pessa, J. Nappi, P. Savolainen, M. Toivonen, R Murison, A. Ovtchinnikov, H. Asonen, J. Lightwave Technol. 14,2357 (1996) F. Daiminger, S. Heinemann, J. Niippi, M. Toivonen, H. Asonen, CLEO'97, paper CFF1, Baltimore, Maryland, ' May 18-23, 1997. J.K. Wade, L.J. Mawst, D. Botez, RF. Nabiev, M. Jansen, to be published in Appl. Phys. Lett. July 14, 1997. 196