Proc. SPIE. 9634, 24th International Conference on Optical Fibre Sensors
KEYWORDS: Tunable lasers, Digital signal processing, Optical sensing, Remote sensing, Gases, Wavelength division multiplexing, Laser spectroscopy, Absorption spectroscopy, Optical networks, Simulation of CCA and DLA aggregates
We propose an optical gas sensing network directly overlaid onto optical access networks, hybrid TDM/WDM-PONs. Centralized remote gas monitoring is demonstrated using three different sensing technologies: Chirp Laser Dispersion Spectroscopy (CLaDS), Direct Laser Absorption Spectroscopy (DLAS) and tunable diode laser absorption spectroscopy (TDLS). DLAS performs fast threshold detection while CLaDS provides quantitative information about the gas. Additionally, TDLS utilizes a cost-effective solution for multiple gases detection. The results confirm that centralized remote gas sensing can be realized in optical communication networks using standard single-mode fiber (SMF), which provides a real time, low cost, and maintenance-free solution.
All-optical virtual private network (VPN), which offers dedicated optical channels to connect users within a VPN group,
is considered a promising approach to efficient internetworking with low latency and enhanced security implemented in
the physical layer. On the other hand, time-division multiplexed (TDM) / wavelength-division multiplexed (WDM)
network architecture based on a feeder-ring with access-tree topology, is considered a pragmatic migration scenario from
current TDM-PONs to future WDM-PONs and a potential convergence scheme for access and metropolitan networks,
due to its efficiently shared hardware and bandwidth resources. All-optical VPN internetworking in such a metro-access
integrated structure is expected to cover a wider service area and therefore is highly desirable. In this paper, we present a
TDM/WDM metro-access integrated network supporting all-optical VPN internetworking among ONUs in different sub-
PONs based on orthogonal differential-phase-shift keying (DPSK) / amplitude-shift keying (ASK) modulation format. In
each ONU, no laser but a single Mach-Zehnder modulator (MZM) is needed for the upstream and VPN signal generation,
which is cost-effective. Experiments and simulations are performed to verify its feasibility as a potential solution to the
future access service.