Optical packet switching (OPS) and optical burst switching (OBS) are regarded as next-generation transport technologies that enable more efficient and flexible utilization of the capacity of optical networks by providing sub-wavelength granularity. Optically labelled packet transmission based on orthogonal intensity-modulation/differential-phase-shift-keying (IM/DPSK) modulation format, in which the payload is intensity modulated while the label is carried by DPSK has been proposed and demonstrated. More recently, it was found that using DPSK/IM for payload/label modulation and a balanced receiver for DPSK detection is more advantageous. In these optical label encoding schemes, two optical modulators are required, one for encoding the payload and the other for the label. In this paper, we demonstrate a novel payload and label encoding technique based on a single Mach Zehnder (MZ) modulator. In this scheme, the RF port of the MZ modulator is used to encode a 10G DPSK payload while the bias port is used to impose the label information through an appropriate intensity modulation. Direct detection of the label is achieved with an inexpensive low-speed receiver while the DPSK payload is decoded by using an optical 1-bit delay interferometer before detection by either a single or a balanced detector. Experimental results show superior receiver sensitivity for both the label and the payload, which compares favourably with previous reported schemes and with the advantage of using only a single modulator. Furthermore, we show that label removal and re-insertion can be realized in the RF domain without any polarization dependence.

Date Published: 13 October 2005
PDF: 8 pages
Proc. SPIE 5970, Photonic Applications in Devices and Communication Systems, 59702K (13 October 2005); doi: 10.1117/12.628145

Published in SPIE Proceedings Vol. 5970:
Photonic Applications in Devices and Communication Systems
Peter Mascher; John C. Cartledge; Andrew Peter Knights; David V. Plant, Editor(s)