Bidirectional multimode-fiber communication links using dual-purpose vertical-cavity devices

Jonathan D. Ingham, Richard V. Penty, Ian H. White

Research output: Contribution to journalArticlepeer-review

25 Citations (SciVal)


This paper describes the development of novel multimode-fiber (MMF) communication links that achieve half-duplex bidirectional transmission over a single fiber through the use of 850-nm dual-purpose GaAs vertical-cavity optoelectronic devices. The dual-purpose devices are fabricated by focused-ion-beam micromachining (FIBM) of standard vertical-cavity surface-emitting lasers (VCSELs) and are able to be switched between operation as either efficient laser sources or as resonant-cavity-enhanced avalanche photodetectors. An avalanche multiplication factor of 10 is achieved at a reverse-bias voltage of 12.3 V. A 1.25-Gb/s half-duplex bidirectional data communication link is demonstrated and shown to allow error-free transmission of binary data over 500 m of standard 50-μm-core-diameter MMF. Receiver sensitivities for transceivers based upon these devices are predicted for the first time to be comparable with conventional data communication transceivers. Furthermore, a half-duplex analog bidirectional system is constructed, which permits the transmission of advanced RF modulation formats over MMF. Link characterization by error-vector magnitude (EVM) is described. The dual-purpose vertical-cavity devices are employed for bidirectional transmission of 32-symbol quadrature-amplitude-modulated (32-QAM) signals on a carrier frequency of 2 GHz, relevant to many current wireless local-area network and cellular standards. EVM as low as 1.3% rms is observed for a 600-m link of 62.5-μm-core-diameter MMF.

Original languageEnglish
Pages (from-to)1283-1294
Number of pages12
JournalJournal of Lightwave Technology
Issue number3
Publication statusPublished - 1 Mar 2006


  • Bidirectional communication
  • Multimode fiber (MMF)
  • Optical fiber LAN
  • Photodiodes
  • Radio over fiber
  • Vertical-cavity surface-emitting lasers (VCSELs)

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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