We have proposed a stable, wideband, and tunable directly modulated fiber ring laser (TDMFRL) by using a reflective semiconductor optical amplifier (RSOA) and an optical tunable filter (OTF). For use in a bidirectional access network, the TDMFRL not only generates downstream data traffic but also serves as the wavelength-selecting injection light source for the Fabry-Pérot laser diode (FP-LD) located at the subscriber site. We experimentally demonstrated a bidirectional transmission at 1.25-Gb/s direct modulation over a 25-km single-mode fiber (SMF), thereby showing good performance in a wavelength division multiplexing (WDM) access network.

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A widely wavelength-tunable erbium-doped-fiber laser (T-EDFL) located at a central office is proposed for the bidirectional highspeed performance testing of wavelength-division-multiplexing access networks in which injection-locked Fabry-Pérot laser diodes located at optical network units are used for upstream transmissions. The T-EDFL not only generates laser light for downstream transmission testing, but also serves as the injection source for upstream transmission testing. It has a wide tunable range of 64 nm (1540 to 1604 nm), a high output power of 2.2 dBm, and a good signal-to-noise ratio above 46 dB. For 10-Gb/s downstream and 1.25-Gb/s upstream transmissions over a 10-km single-mode fiber (SMF), power penalties at a bit error rate of 10 − 9 are less than 0.94 dB and 0.76 dB (1.26 dB and 1.68 dB) for downstream and upstream transmissions at C-band (at L-band) wavelengths, respectively. In the transmissions over a 25-km SMF, the penalties are 2.24 dB and 2.36 dB (3.66 dB and 4.18 dB) at C-band (at L-band) for downstream and upstream transmissions, respectively. C 2010 Society of Photo-Optical Instrumentation Engineers.

In this paper, a low-cost passive optical network scheme is presented for intelligent buildings located in areas having difficulty with wireless signal reception. The network can simultaneously broadcast digital-video-broadcasting-terrestrial (DVB-T) signals and can transmit high-speed data bidirectionally using a Fabry-Pérot laser diode (FP-LD) injection-locked by a vertical cavity surface-emitting laser (VCSEL). Results are shown for the broadcast of DVB-T signals over an 1-km multimode fiber (MMF) and for non-return-to-zero (NRZ) data over a 25-km single mode fiber (SMF). Downstream and upstream transmission bit rates are 10 Gbps and 1.25 Gbps, respectively. Maintaining TV signal quality at 40%, receiver sensitivities are -20.2 dBm and -22.58 dBm for downstream and upstream transmissions, respectively. In addition, the constraint of injection-locking and the limitation of optical power are also analyzed.