1.55 /spl mu/m DFB laser integrated on erbium doped phosphate glass substrate

Summary form only given. The development of WDM)telecommunications systems has driven the rapid development of erbium doped fiber amplifier and very narrow band lasers. Recently, new efficient waveguide amplifier on phosphate glass has been demonstrated. In this paper, we present the first steps of fabrication and analysis of 10 monolithically integrated DFB lasers on a chip. The starting point of our work is an Er/Yb codoped phosphate glass, on which buried channel waveguides have been realized using ion exchanged techniques. Recent progress in that technology has led to a gain of 3dB/cm. The waveguides present a mean index variation of 2.10/sup -2/ above substrate refractive index value of 1.52. For operation at 1.55 /spl mu/m, the grating period predicted by the Bragg phase matching condition is d = /spl lambda//2n/sub e/ = 0.505 /spl mu/m related to the mean effective index n/sub e/ of the waveguides. In this work, a corrugate 1 cm long grating was made on the top of the wafer. Interferometric exposure of photoresist with an Ar/sup +/ laser operating at 488 nm was used to print the grating. After development, the grating pattern is transferred on the glass surface through a reactive ion etching process. The glass is etched sufficiently to get more than 60% of reflectivity at Bragg wavelength. Under pumping at 980 nm, single longitudinal mode operation around 1.55 /spl mu/m is demonstrated for all the ten waveguides of the chip.