Richard Lauder

Optical add-drop multiplexers with low crosstalk

We propose and demonstrate three new optical add-drop multiplexer (OADM) architectures with simple and compact configuration and excellent crosstalk performance. The OADMs use a single multiport optical circulator and either one or two narrow-band fiber Bragg gratings, depending on the crosstalk requirement.

WDM ring network employing a shared multiwavelength incoherent source

We propose and demonstrate a novel wavelength-division multiplexed (WDM) ring-network for wide-area, local-area, and access networks. The network employs a single, shared, multiwavelength incoherent source that is remotely located from network nodes. The use of a single incoherent source provides a straight-forward means of wavelength stabilization and potential for a cost-effective network. We demonstrate less than 10/sup -9/ bit-error-rate (BER) operation of a four-node network at per-node data rates of 622 Mb/s.

Baseband optical carrier-sense multiple access - demonstration and sensitivity measurements

We demonstrate for the first time baseband optical carrier-sense multiple access with collision avoidance. We evaluate the performance of the baseband carrier-sense circuit with bit- and packet-error-rate measurements. The sensitivity of the carrier-sense circuit is -51.6 dBm.

Compact optical add-drop multiplexers with low homodyne crosstalk using a single optical circulator and fiber Bragg gratings

We propose and demonstrate new optical add/drop multiplexer (OADM) architectures with simple and compact configuration and excellent crosstalk performance. The OADMs use a single optical circulator and either one or two narrowband fiber Bragg gratings.

Suppression of RF noise tones caused by Rayleigh backscatter in to an unisolated laser using audio-frequency external optical-phase modulation

When Fabry-Perot lasers are subject to Rayleigh backscatter, dramatic line-narrowing and frequency hopping up to 500 MHz, evidenced by radio-frequency (RF) tones, are observed. These RF tones will severely degrade the system performance of a subcarrier multiplexed transmission system, such as quadrature phase-shift keying. In this letter, it is demonstrated that audio-frequency external optical-phase modulation can suppress the noise tones and restore the laser linewidth. This scheme may offer an inexpensive alternative to optical isolators to recover the system performance and thus is very important for cost-effective customer access networks.

Analytical model describing transients within a gain-clamped erbium-doped fiber amplifier

We present an analytical model suitable for investigation of transient effects within a gain-clamped erbium-doped fiber amplifier (EDFA) experiencing a change to the input signal or pump power. We test the validity of assumptions made and discuss the limitations of the model presented.

RF-noise-tone suppression in QPSK transmission with unisolated Fabry-Perot lasers

We have demonstrated a simple, economical method to suppress RF noise tones from subcarrier multiplexed networks that use unisolated Fabry-Perot lasers. This method has no insertion loss. This method will be appropriate for the cost-sensitive upstream transmission of access networks such as hybrid-fiber coax and future SCM all-optical access networks. This method increases the RF input power dynamic range at the transmitting laser by at least 20 dB if an unisolated Fabry-Perot laser is used, and by 1.6 dB compared to the use of a conventionally isolated laser.

Experimental Demonstration of a WDM Ring Network Employing a Hybrid EDFA as a Shared Multi-Wavelength Source

We propose a WDM ring-network for MAN, LAN or access applications, using spectral-slicing of a single, shared, multi-wavelength source, based on a hybrid EDFA. We demonstrate less than 10−9 bit-error-rate operation of a four-node network at per-node data rates of 622 Mbit/s.