DETAILS OF THE ACHIEVEMENT
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Surviving channel power transients in TDM-pumped lumped Raman fibre amplifier
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Miroslav Karásek, DSc. |
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| Year: 2009 |
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Fast signal power transients caused by cross-gain saturation effects
constitute a serious limitation in WDM transmission systems and
networks with cascades of optical amplifiers. Photonic switching
elements in transparent networks, such as reconfigurable optical add
drop multiplexers, provide a platform to support greater network
flexibility through wavelength rerouting. In such networks the number
of optical channels passing through a fiber amplifier may vary. These
variations cause power transients in “surviving” channels. Two
control schemes have been suggested for suppression of surviving
channel power transients in networks based on erbium-doped fibre
amplifiers: fast pump power control, and all-optical gain clamping
(AOGC).
We have experimentally investigated suppression of surviving channel
power transients in an AOGC time-division-multiplexed (TDM)-pumped
lumped Raman fiber amplifier ( TDM LRFA). The TDM LRFA consisted of 13
km long dispersion compensating fiber (DCF) counter-directionally
pumped by 4 pairs of laser diodes powered from microprocessor
controlled pulse generator. Gain clamping was achieved by the
introduction of a cavity around the Raman gain medium for the lasing
wavelength. Channel addition/removal was simulated by transmitting 19
signals, light of 5 channels was modulated at 10 Gb/s, eight channels
was 100% square-wave modulated at 2 kHz. Schematic diagram of the
experimental set-up is shown in Fig. 1 [8]. Figure 2 demonstrates the
suppression of power transients of channel the 1554.94 nm 10 GE
signal: comparison of unclamped and AOGC regime [9].
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- Karasek, M. – Radil, J. Vojtech, J. – Surviving Channel Power Transients in TDM-Pumped Lumped Raman Fiber Amplifier. Proc. OFC/NOFC (2009), San Diego, s. JThA13
- Karasek, M. – Radil, J. – Vojtech, J. – Power transients in time-division multiplexed discrete Raman fibre amplifier. Optics Communications, sv. 282, (2009), s. 2944-2949.
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