A novel method of interconnecting high-performance computers, predicated on the bit-parallel transmission of data, using monolithic, mode-locked WDM array sources, ten wavelengths wide, operating at greater than 20 GHz, is being developed. The byte-wide data is coupled to a single-mode fiber of appropriate dispersion characteristics, and the byte synchronism is maintained by means of a 'shepherd soliton'. The shepherding condition requires that the photonic components between the WDM array and the single- mode fiber, not introduce any skew which cannot be corrected by the shepherd soliton. This requires that the passive component skew be within the capture range of the shepherd pulse. In this paper we describe the impact of the shepherding condition on the design of the passive WDM components, and we describe a suitable coupler design, based on planar lightwave circuits and the corresponding planar lightwave circuit design rules.