Modeling of InGaAsP-InP 1.55 µm lasers with integrated mode expanders using fiber-matched leaky waveguides

A new concept for InGaAsP-InP 1.55 mum lasers integrated with spot size converters using leaky waveguides is presented. The large fundamental mode size and the high discrimination of the higher order modes make ARROWs (Antiresonant Reflecting Optical Waveguides) and antiguided waveguides useful for fiber coupling functions. Three-dimensional (3-D) beam propagation method (BPM) results show that the devices have transformation losses lower than 0.22 dB. Fiber-coupling efficiencies of 60% are possible with standard cleaved single-mode fibers (SMF). The horizontal and vertical FWHM can be efficiently reduced to 9.70 degrees (horizontal) and 17.80 degrees (vertical). The fabrication of such devices avoids the growth of thick layers of quaternary material with a low Ga and As fraction, and simplifies the fabrication to one planar epitaxial growth step and one non-critical conventional etch

Oxide-confined laser diodes with an integrated spot-size converter

We report a new technique for the monolithic integration of a GaAs-based InGaAs-GaAs strained quantum-well laser and a spot-size converter (SSC to improve the fiber coupling characteristics. The selective wet oxidation of AlGaAs is used to simplify the fabrication scheme of the component to a single planar epitaxial growth step and one conventional noncritical etch. This approach also allows us to avoid the photolithography of narrow features. An excellent reproducibility of the fabrication scheme was found. The integrated SSC exhibits very low transformation losses and a low beam divergence of 7.5degrees x 13.5degrees. The coupling efficiency to a 980-nm single-mode fiber is improved from -6.34 dB for a reference laser to - 1.49 dB for the tapered device. The - 1-dB alignment tolerance is +/-1.5 mum in the transverse direction and +/- 1.6 mum in the lateral direction, respectively

Spot size converters for low cost PICs

The coupling loss and the packaging cost of photonic integrated circuits (PICs) can be much reduced by monolithic integrated mode size converters (tapers). During the past years, many taper designs have been reported. This paper presents a classification from an optical point of view