Fiber-chip-coupling based on in InP V-groove technology

We study a simple and low cost technological concept for active or passive fiber-waveguide coupling. Lateral and vertical alignment of optical fibers is achieved using InP V-grooves. Using conventional photolithography, wet chemical etching techniques and a special acrylic adhesive, tapered and non-tapered single mode fibers (SMF) have been coupled to 1.55 μm waveguide electroabsorption (EA) modulators. Experimentally, a fiber-chip coupling loss of 9.5 dB is determined for non-tapered cleaved single mode fibers. Preliminary experimental results using tapered SMF exhibit a lower coupling loss and from numerical simulations a minimum coupling loss of less than 2.5 dB is expected. To our knowledge, this is the first time, InP V-groove technology is utilized for fiber-chip coupling of a waveguide EA-modulator