  We describe a micromachining process to allow the coupling of an array of
single-mode telecommunication fibers to individual superconducting nanowire
single photon detectors (SNSPDs). As proof of principle, we show the
integration of four detectors on the same silicon chip, including two standard
single-section nanowire detectors and two superconducting nanowire avalanche
photodetectors (SNAPs) with modified series structure without external
inductor, and their performances are compared. The SNAP shows saturated system
detection efficiency of 16% while the dark count rate is less than 20 Hz,
without the use of photon-recycling reflectors. The SNAP also demonstrates
doubled signal-to-noise ratio, reduced reset time (~ 4.9 ns decay time) and
improved timing jitter (62 ps FWHM) compared to standard SNSPDs.
