Compact latching-type single-mode-fiber switches fabricated by afiber-micromachining technique and their practical applications

摘要

The design, fabrication, optical and mechanical characteristics,nand reliability of several kinds of the latching-type single-mode-fibern(SMF) switch are reported. Practical applications of these switches tonoptical fiber communication systems and optical testing and sensingnsystems are also demonstrated. In the developed switches, a movablenfiber is actuated by the magnetic attraction force produced betweennpermanent magnets and a micromagnetic-alloy pipe fixed around the fiber.nThe ultralight micropipes (0.13 (i.d.)-0.18 (o.d.)×5Lnmm, 400 Μg) were successfully massproduced by a fiber-micromachiningntechnique based on metallizing and etching of sacrificial fibers. Wenused a refractive-index-matching oil in the switches to reduce insertionnloss and reflected light. The several hundred fabricated 1×2nstandard SMF switches exhibited excellent optical characteristics, suchnas typical insertion loss of 0.36 dB, return loss of 49 dB and crosstalknof -70 dB. They exhibited stable latching-type operation with lossnchanges of below 0.1 dB during 105 switching operations withnminimum driving power of 9 mW and switching time of 2 ms. The switchesnwere subjected to endurance (108 switching operations), heatncycles, shock and vibration, and long-term (6.5 years) intermittentnoperation tests, and revealed no significant optical or mechanicalndegradation. A 1×8 latching-type SMF switch was constructed usingnseven 1×2 switches cascaded in three stages and uniform insertionnlosses of below 0.7 dB and return losses of over 47 dB at each of eightnports were obtained. The 1×2 and 1×8 switches have beennapplied to NTT's optical communication systems. We fabricated a compactnand cost-effective wavelength switch by installing microfilter chips innthe 1×2 switch and confirmed stable latching-type wavelengthnswitching between 1.3- and 1.55-Μm optical signals. We also designednand fabricated a polarization-maintaining switch using polarizationnmaintaining and absorption reducing (PANDA) fibers and confirmed stablenpolarization maintaining switching operations. These switches arenapplicable not only to optical fiber communication systems, but also tonoptical testing and sensing systems