Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887
banner image
image of Volume 4, Issue 1
Online ISSN 1751-8776 Print ISSN 1751-8768

IET Optoelectronics

Volume 4, Issue 1, February 2010

Volumes & issues:

Volume 4, Issue 1

February 2010

Show / Hide details

    • Plasmonic/metallic passive waveguides and waveguide components for photonic dense integrated circuits: a feasibility study based on microwave engineering
      • Author(s): E. Berglind ; L. Thylén ; L. Liu
      • Source: IET Optoelectronics, Volume 4, Issue 1, p. 1 –16
      • DOI:  10.1049/iet-opt.2008.0045
      • Type: Article
      • + Show details - Hide details
      • p. 1 –16 (16)
        To investigate the potential for dense integration of photonic components, we analyse passive plasmonic/metallic waveguides and waveguide components at optical frequencies by using mostly microwave engineering approaches. Four figures of performance are formulated that are utilised to compare the characteristics of four different slab waveguides with zero frequency cut-off modes. Three of these are metallic based whereas the fourth one, which also serves as a reference, is dielectric based with high index-contrast. It is found that all figures of performance cannot be optimised independently; in particular there is a trade-off between the waveguide Q-value and the transversal field confinement. Microwave methods are used to design several photonic transmission line components. The small Q-value of the metallic waveguides is the main disadvantage when using materials and telecom frequencies of today. Hence plasmonic waveguides do not offer full functionality for some important integrated components, being severe for frequency-selective applications. To achieve a dense integration, it is concluded that new materials are needed that offer Q-values several orders of magnitude higher than metals.
        Add to favourites
        Export citations
      Coded-orthogonal frequency division multiplexing in hybrid optical networks
      • Author(s): I.B. Djordjevic
      • Source: IET Optoelectronics, Volume 4, Issue 1, p. 17 –28
      • DOI:  10.1049/iet-opt.2008.0059
      • Type: Article
      • + Show details - Hide details
      • p. 17 –28 (12)
        Future Internet should be able to support a wide range of services containing large amount of multimedia over different network types at a high speed. The future optical networks will therefore be hybrid, composed of different single-mode fibre (SMF), multi-mode fibre (MMF) and free-space optical (FSO) links. In these networks, novel modulation and coding techniques are needed that are capable of dealing with different channel impairments, be it in SMF, MMF or FSO links. The authors propose a coded-modulation scheme suitable for use in hybrid FSO – fibre-optics networks. The proposed scheme is based on polarisation-multiplexing and coded – orthogonal frequency division multiplexing (OFDM) with large girth quasi-cyclic low-density parity-check (LDPC) codes as channel codes. The proposed scheme is able to simultaneously deal with atmospheric turbulence, chromatic dispersion and polarisation mode dispersion (PMD). With a proper design for 16-quadrature amplitude modulation (QAM)-based polarisation-multiplexed coded-OFDM, the aggregate data rate of 100 Gb/s can be achieved for OFDM signal bandwidth of only 12.5 GHz, which represents a scheme compatible with 100 Gb/s per wavelength channel transmission and 100 Gb/s Ethernet.
        Add to favourites
        Export citations
      Design considerations of high performance optical code division multiple access: a new spectral amplitude code based on laser and light emitting diode light source
      • Author(s): H.A. Fadhil ; S.A. Aljunid ; R.B. Ahmad
      • Source: IET Optoelectronics, Volume 4, Issue 1, p. 29 –34
      • DOI:  10.1049/iet-opt.2009.0010
      • Type: Article
      • + Show details - Hide details
      • p. 29 –34 (6)
        A new code of optical code division multiple access (OCDMA) based on spectral amplitude coding (SAC) is described and analysed. The coding technique is called random diagonal (RD) code. One of the important properties of this code is that the cross-correlation at data segment is always zero, which means that phase intensity induced noise (PIIN) is reduced. From the construction of RD code sequence, the authors can see that the RD code is constructed using code segment and data segment. Using this code property, RD code is implemented using coherent source (multi-laser) and incoherent source (light emitting diode) for the code segment and data segment, respectively. RD code using two multi-sources (incoherent and coherent) can be considered as an effective way for maximising the capacity while minimising the cost of SAC–OCDMA. It is shown that the system using this new code matrices not only suppresses PIIN, but also allows a larger number of active users compared with other codes.
        Add to favourites
        Export citations
      Coupled cavity InGaAsP/InP laser for synthetic optical coherence tomography and other applications
      • Author(s): F.K. Khan ; J. Wang ; D.T. Cassidy
      • Source: IET Optoelectronics, Volume 4, Issue 1, p. 35 –45
      • DOI:  10.1049/iet-opt.2008.0065
      • Type: Article
      • + Show details - Hide details
      • p. 35 –45 (11)
        The authors describe widely tunable coupled cavity semiconductor lasers with sub-microsecond switching times between modes over the operating range of ∼100 nm. With appropriate modulation of injection currents and time averaging of the output, these devices provide short coherence lengths and can be an excellent source for synthesised optical coherence tomography (OCT). The depth resolution was found to be ∼15 µm for a 100 nm wavelength tuning range centred at 1580 nm. High-output power and brightness together with a short coherence length confers on these asymmetric multiple quantum well (AMQW) C3 laser some advantages over conventional sources for OCT. Also, a rapid wavelength switching capability allows the AMQW C3 lasers to be used in real-time OCT and other applications needing wavelength agile sources.
        Add to favourites
        Export citations
      Service differentiated drop code unit for metro ring optical networks
      • Author(s): S.B.A. Anas ; T.J. Quinlan ; S.D. Walker
      • Source: IET Optoelectronics, Volume 4, Issue 1, p. 46 –50
      • DOI:  10.1049/iet-opt.2008.0067
      • Type: Article
      • + Show details - Hide details
      • p. 46 –50 (5)
        The authors demonstrate using both simulation and experiment, a drop code unit for metro ring optical networks with service differentiation capability. This is achieved by means of a spectral amplitude coding technique whereby the code weight in a particular channel is varied to provide different signal quality levels. Transmission of three channels with different weights operating at 10 Gbps per channel was simulated over a 68 km unamplified and 185 km amplified links of dispersion compensated fibre. Services are perfectly dropped at bit error rates from 10−9 to 10−3, leaving the through service free from accumulated noise. The authors also present a 2.5 Gbps per channel proof-of-concept experiment over 40 km of single-mode fibre (SMF).
        Add to favourites
        Export citations

Most viewed content for this Journal

Article
content/journals/iet-opt
Journal
5
Loading

Most cited content for this Journal

Print this page
This is a required field
Please enter a valid email address