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Coherent ultra-dense wavelength division multiplexing (UDWDM) architecture constitutes an approach to serve hundreds of users in a passive optical network (PON) with high spectrum efficiency. We propose and experimentally test a directly phase modulated distributed feedback (DFB) laser with a Nyquist shaped beat signal. An Rx sensitivity of −44 dBm at BER=10e-3 is achieved for dedicated 2.5 Gb/s/user...
Direct phase modulation of DFB is demonstrated with DPSK, DQPSK and Duobinary modulation formats and detected with an intradyne receiver based on a 120-degree hybrid. The system is tested in a 50 km fibre link with 6.25 GHz channel spacing among users in a UDWDM-PON. By using higher modulation formats, the spectral efficiency can be increased in a single carrier system without spectral shaping while...
Ultra-dense access network attracts people's attention recently; however, until now it is difficult to implement it commercially owing to cost, footprint, and the traditional complexity of coherent receiver. Single laser, especially integrated laser-based optical network unit (ONU) provides a potential system for simplifying the ONU. Here, we show a 2.5-Gb/s/user bidirectional transmission with 5-GHz...
A 6.25GHz spaced UDWDM PON is experimentally tested with directly-phase modulated lasers, polarization scrambling and homodyne detection. Bitrates from 1.25Gb/s to 5Gb/s per λ are achieved in a 50km fibre-link serving up to 1024 users.
We experimentally demonstrate a novel low-cost transmitter based on a directly modulated DFB with phase diversity in time. A sensitivity of −38dBm at 2.5Gb/s was achieved for 6.25GHz spaced UDWDM-PON with a simple intradyne receiver having 1 photodiode per polarization.
A chip integrated DFB-EAM is proposed as Tx with direct phase modulation and coherent detection. We achieved a 2dB performance enhancement in the Rx sensitivity by mitigating the residual IM produced in the optical PSK signal.
A centralized polarization scrambling and single-PD coherent ONU Rx system is proposed and tested with two Tx and direct-phase modulated DFBs. Polarization independence at the Rx, and a sensitivity at BER=10−3 of ×45dBm with 7.5GHz channel spacing were achieved.
The response of a DFB was equalized with a simple RC network for modulating directly its phase and producing a BPSK signal. The system was tested with a heterodyne coherent detector at 1.25 Gb/s and 2.5 Gb/s showing a sensitivity penalty of around 1dB when compared with external phase modulation. The results indicate that the technique could be considered as a reliable low-cost ONU transmitter solution...
The upstream of an OFDM-PON with direct modulated lasers tuned in temperature was experimentally tested. Results demonstrate flexible bandwidth allocation, and show it constitutes an efficient strategy to cope with the differential link-loss among the users in the PON.
In this paper, an optimal trade-off between the Optical Distribution Network (ODN) power budget and the upstream optical Signal-to-Rayleigh Ratio (US-oSRR), for a Single- Fibre/Wavelength TDM-PON rSOA-based ONU network is presented. Up to 32 ONUs can be reached over a practical implementation. Burst operation is considered.
Downstream FSK modulation allows for simple wavelength reuse in WDM-PON; the intrinsic distortion of the laser FM response is here compensated by means of Quantized Feedback Equalization, avoiding the need for precoding.
We present a new remotely-amplified single-fibre-tree double-fibre-ring PON architecture for large capacity and scalability. We show its feasibility demonstrated by experimental results from our test-bed.
Highly-scalable PON architectures enabling single-fibre access, colourless ONU, resiliency and centralized light-generation control are discussed; they represent an intermediate step towards metro-access convergence.
With the purpose of reducing the crosstalk caused by Rayleigh Backscattering and interferometric interferences in bidirectional centralized light systems, we propose and experimentally demonstrate an optical frequency modulation to broaden the optical spectrum effectively.
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