This paper discusses the potential for opening a new wavelength window at the 2 μm waveband for optical communications, showing current limitations of the system's performance. It focuses on novel results for key enabling technologies, including the analysis of laser injection locking at this waveband, an improved responsivity for bulk and strained InGaAs edge-couple detectors, and also an increased gain profile for thulium-doped fiber amplifiers.

The authors present results on the performance of a hybrid external cavity photonic crystal laser-comprising semiconductor optical amplifier, and a 2D photonic crystal cavity fabricated in low-temperature amorphous silicon. The authors demonstrate that lithographic control over amorphous silicon photonic crystal cavity-resonant wavelengths is possible, and that single-mode lasing at optical telecommunications wavelengths is possible on an amorphous silicon platform.

High speed back-to-back transmission of NRZ data at 12.5 Gbit/s was achieved over a repeaterless optical network without the use of forward error correction or optical clock recovery using a hybrid integrated silicon photonics optical interconnect. The interconnect comprises an electroabsorption modulator based on dilute nitride multiple quantum well material on GaAs substrate optically coupled to large core silicon waveguide using passive alignment and flip-chip bonding.

The authors describe a fast and efficient technique for lensed fibre to waveguide coupling, based upon imaging the waveguide facets. In this technique, the lensed fibre is scanned across a ridge waveguide facet while the reflected power from the facet is measured through a circulator. The measurements allow for the facet to be imaged and the lensed fibre location that provides optimum coupling can be determined. The technique provides an optimal method of coupling light into micron‐scale passive waveguide structures, with an efficiency close to that of the theoretical limit.

A directly modulated silicon photonic DFB laser integrated with a SOA was used to validate error-free transmission over 25 km of standard single mode fiber at 1310 nm. Data in NRZ format at a rate of 10 Gbit/s with PRBS of length 231-1 were used in the experiment.