All-optical Subsystems Research Articles

Photonics for Solving Unbundling in Next-Generation WDM-PON

Modern telecommunication networks are quickly evolving from passive content use to an evolutionary and much more participative social model that demands huge capacity, low power consumption, and low cost. Wavelength-division-multiplexing passive optical network (WDM PON) represents one of the current solutions to meet different network requirements. Nevertheless, in order to fully exploit the potential of WDM PON, unbundling issues still require a more efficient management, specially when the network connections get higher, to achieve high flexibility, scalability, minimum hiring together with low power consumption and low cost. Here, unbundling in WDM PON is handled in optical domain in order to exploit the higher bandwidth optics can offer with respect to electronics, avoiding high power consuming due to optical-electrical-optical (OEO) conversions. The use of photonic signal processing enables not only high bit rate but also scalability, easy reconfigurability, modularity, minimum number of fiber links, and “pay as you grow” strategy implementation. An innovative architecture based on WDM/time-division-multiplexing conversion is proposed, and all required all-optical subsystems are experimentally demonstrated, as proof of concept, exploiting nonlinear optical fiber. Power penalty lower than 3 dB is verified for each optical block. Power requirements for each subsystem are also reported. Moreover, the use of new integrated technologies can strongly reduce power consumption footprint and implementations cost.

Ultrafast, atto-Joule switch using fiber-optic parametric amplifier operated in saturation

All-optical manipulation of signals carried by lightwaves is attractive because controlling the light directly can be more efficient, allows a multitude of signal formats, and can also prove most cost effective. We implemented a novel scheme for ultrafast optical switching using very small control energy that relies on the use of a saturated fiber-optic parametric amplifier. Approximately 19 aJ (150 photons) of control pulse energy was needed for 50% extinction of the signal which is three to four orders of magnitude smaller than in other all-optical switching demonstrations. This allows the consideration of novel practical approaches to implement all-optical switching devices and all-optical subsystems for telecommunications and other applications.

Ultrafast, atto-Joule switch using fiber-optic parametric amplifier operated in saturation

All-optical manipulation of signals carried by lightwaves is attractive because controlling the light directly can be more efficient, allows a multitude of signal formats, and can also prove most cost effective. We implemented a novel scheme for ultrafast optical switching using very small control energy that relies on the use of a saturated fiber-optic parametric amplifier. Approximately 19 aJ (150 photons) of control pulse energy was needed for 50% extinction of the signal which is three to four orders of magnitude smaller than in other all-optical switching demonstrations. This allows the consideration of novel practical approaches to implement all-optical switching devices and all-optical subsystems for telecommunications and other applications.

All-Optical 3R Burst-Mode Reception at 40 Gb/s Using Four Integrated MZI Switches

We demonstrate an all-optical retime, reshape, reamplify (3R) burst-mode receiver (BMR) operating error-free with a 40-Gb/s variable-length asynchronous optical data packets that exhibit up to 9-dB packet-to-packet power variation. The circuit is completely based upon hybrid integrated Mach-Zehnder interferometric (MZI) switches as it employs four cascaded MZIs, each one performing a different functionality. The 3R burst-mode reception is achieved with the combination of two discrete all-optical subsystems. A reshape, reamplify BMR employing a single MZI is used first to perform power equalization of the incoming bursts and provide error-free data reception. This novel approach is experimentally demonstrated to operate error-free, even for a 9-dB dynamic range of power variation between bursty data packets and for a wide range of average input power. The obtained power-equalized data packets are then fed into a 3R regenerator to improve the signal quality by reducing the phase and amplitude jitter of the incoming data. This packet-mode 3R regenerator employs three MZIs that perform wavelength conversion, clock extraction, and data regeneration for every packet separately and operates at 40 Gb/s, exhibiting rms timing jitter reduction from 4 ps at the input to 1 ps at the output and a power penalty improvement of 2.5 dB

40-Gb/s All-Optical Processing Systems Using Hybrid Photonic Integration Technology

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents an experimental performance characterization of all-optical subsystems at 40 Gb/s using interconnected hybrid integrated all-optical semiconductor optical amplifier (SOA) Mach–Zehnder interferometer (MZI) gates and flip-flop prototypes. It was shown that optical gates can be treated as generic switching elements and, when efficiently interconnected, can form larger and more functional network subsystems. Specifically, this paper reports on all-optical subsystems capable of performing on-the-fly packet clock recovery, 3R regeneration, label/payload separation, and packet routing using the wavelength domain. The all-optical subsystems are capable of operating with packet-mode traffic and are suitable for all-optical label-switched and self-routed network nodes. The intelligent functionality offered, combined with the compactness and stability of the optical gates, verifies the potential that all-optical technology can find application in future data-centric networks with efficient and dynamic bandwidth utilization. This paper also reports on the latest photonic integration breakthroughs as a potential migration path for reducing fabrication cost by developing photonic systems-on-chip utilizing multiple SOA-MZI optical gates on a single chip. </para>

All-optical network subsystems using integrated SOA-based optical gates and flip-flops for label-swapped networks

In this letter, we demonstrate that all-optical network subsystems, offering intelligence in the optical layer, can be constructed by functional integration of integrated all-optical logic gates and flip-flops. In this context, we show 10-Gb/s all-optical 2-bit label address recognition by interconnecting two optical gates that perform xor operation on incoming optical labels. We also demonstrate 40-Gb/s all-optical wavelength-switching through an optically controlled wavelength converter, consisting of an integrated flip-flop prototype device driven by an integrated optical gate. The system-level advantages of these all-optical subsystems combined with their realization with compact integrated devices, suggest that they are strong candidates for future packet/label switched optical networks