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M. Nedeljkovic  - - - 
Top co-authors See all
Graham T. Reed

136 shared publications

Optoelectronics Research Centre, University of Southampton, Southampton SO17 1JB, UK

David Thomson

93 shared publications

Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK

Ali Z. Khokhar

51 shared publications

Univ. of Southampton (United Kingdom)

Vittorio M. N. Passaro

41 shared publications

Electrical and Information Engineering, Politecnico di Bari, Bari, ba Italy 70125 ()

Callum G. Littlejohns

29 shared publications

Optoelectronics Research Centre, University of Southampton, University Road, Southampton, Hampshire SO17 1BJ, UK

Publication Record
Distribution of Articles published per year 
(2011 - 2019)
Total number of journals
published in
Publications See all
Article 1 Read 0 Citations Silicon-on-insulator free-carrier injection modulators for the mid-infrared M. Nedeljkovic, C. G. Littlejohns, A. Z. Khokhar, M. Banakar... Published: 11 February 2019
Optics Letters, doi: 10.1364/ol.44.000915
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Experimental demonstrations of silicon-on-insulator waveguide-based free-carrier effect modulators operating at 3.8 μm are presented. PIN diodes are used to inject carriers into the waveguides, and are configured to (a) use free-carrier electroabsorption to create a variable optical attenuator with 34 dB modulation depth and (b) use free-carrier electrorefraction with the PIN diodes acting as phase shifters in a Mach–Zehnder interferometer, achieving a VπLπ of 0.052 V·mm and a DC modulation depth of 22 dB. Modulation is demonstrated at data rates up to 125 Mbit/s.
Article 0 Reads 0 Citations Experimental quantification of the free-carrier effect in silicon waveguides at extended wavelengths David E. Hagan, Milos Nedeljkovic, Wei Cao, David J. Thomson... Published: 03 January 2019
Optics Express, doi: 10.1364/oe.27.000166
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We examine the electro-optic effect at wavelengths ranging from 1.31 to 2.02 μm for: (1) an Electronic Variable Optical Attenuator (EVOA); and (2) a Micro-Ring Resonator (MRR). For the EVOA, simulations were performed to ascertain the relationship between free-carrier concentration and optical attenuation, and are in agreement with our observation of an increase in attenuation with increasing wavelength. MRRs were fabricated for use around wavelengths of 2 μm to explore the sensitivity of operation to bus-to-ring coupling gap and p-n junction offset. Trends observed in the experiment are replicated by simulation, calibrated using the observations of the EVOA operation. The previously proposed efficiency increase of operation around 2 μm compared to more traditional wavelengths is demonstrated. Future development of devices for these wavelengths, supported by amplification using Thulium Doped Fiber Amplifier (TDFA) technology, is a promising route to aid in the alleviation of increasing demands on communication networks.
Article 0 Reads 0 Citations Suspended low-loss germanium waveguides for the longwave infrared A. Osman, M. Nedeljkovic, J. Soler Penades, Y. Wu, Z. Qu, A.... Published: 07 December 2018
Optics Letters, doi: 10.1364/ol.43.005997
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Germanium is a material of high interest for mid-infrared (MIR) integrated photonics due to its complementary metal–oxide–semiconductor (CMOS) compatibility and its wide transparency window covering the 2–15 μm spectral region exceeding the 4 and 8 μm limit of the silicon-on-insulator platform and Si material, respectively. In this Letter, we report suspended germanium waveguides operating at a wavelength of 7.67 μm with a propagation loss of 2.6±0.3 dB/cm. To the best of our knowledge, this is the first demonstration of low-loss suspended germanium waveguides at such a long wavelength. Suspension of the waveguide is achieved by defining holes alongside the core providing access to the buried oxide layer and the underlying Si layer so that they can be wet etched using hydrofluoric acid and tetramethylammonium hydroxide, respectively. Our MIR waveguides create a new path toward long wavelength sensing in the fingerprint region.
Article 0 Reads 1 Citation High-speed silicon modulators for the 2 μm wavelength band Wei Cao, David Hagan, David J. Thomson, Milos Nedeljkovic, C... Published: 28 August 2018
Optica, doi: 10.1364/optica.5.001055
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The 2 μm wavelength band has become a promising candidate to be the next communication window. We demonstrate high-speed modulators based on a 220 nm silicon-on-insulator platform working at a wavelength of 1950 nm, using the free carrier plasma dispersion effect in silicon. A Mach–Zehnder interferometer modulator and a microring modulator have been characterized. At 1950 nm, the carrier-depletion modulator operates at a data rate of 20 Gbit/s with an extinction ratio of 5.8 dB and insertion loss of 13 dB. The modulation efficiency (Vπ·Lπ) is 2.68 V·cm at 4 V reverse bias. The device operation is broadband, and we also characterize its performance at 1550 nm. At 1550 nm, an open eye is obtained at 30 Gbit/s. The difference in bandwidth is caused by the bandwidth limit of the 2 μm measurement setup. We also show a ring modulator paired with a low power integrated driver working in hybrid carrier depletion and injection mode at a data rate of 3 Gbit/s with power consumption of 2.38 pJ/bit in the 2 μm wavelength range. This work is a proof of principle demonstration and paves a route toward a full silicon-based transceiver in the 2 μm window.
PROCEEDINGS-ARTICLE 0 Reads 0 Citations 20-Gb/s Silicon Optical Modulators for the 2 μm Wavelength Band Wei Cao, David J. Thomson, Milos Nedeljkovic, Shaif-Ul Alam,... Published: 01 August 2018
2018 IEEE 15th International Conference on Group IV Photonics (GFP), doi: 10.1109/group4.2018.8478691
DOI See at publisher website
Article 1 Read 1 Citation Chalcogenide glass waveguides with paper-based fluidics for mid-infrared absorption spectroscopy Vinita Mittal, Milos Nedeljkovic, David J. Rowe, Ganapathy S... Published: 13 June 2018
Optics Letters, doi: 10.1364/ol.43.002913
DOI See at publisher website