[Show abstract][Hide abstract] ABSTRACT: Wavelength conversion of 40 Gb/s and 80 Gb/s return-to-zero on-off-keying signals using a quantum-dot semiconductor optical amplifier in combination with a delay interferometer as subsequent filter is demonstrated. The performance of the 80 Gb/s wavelength converter measured in terms of the bit-error ratio demonstrated here is the highest reported up to now for quantum-dot semiconductor optical amplifiers. The typical fast gain dynamics manifests itself in open eye diagrams of the converted signal. The slow phase dynamics of the carrier reservoir however induces severe patterning and requires compensation. Adaptation of the free-spectral range of the delay interferometer is necessary in order to mitigate these phase effects and to achieve error-free wavelength conversion.
[Show abstract][Hide abstract] ABSTRACT: Filter assisted all-optical wavelength conversion using a quantum dot (QD) based semiconductor optical amplifier (SOA) is presented. Cross-gain modulation and cross-phase modulation were both used to shift the wavelength of 40-Gb/s and 80-Gb/s return-to-zero on-off keying data signals at 1.3 μm by 10 nm. The ultra-fast gain recovery of the QD's enables open eyes of the wavelength converted signal with an inverted bit-logic. The slow phase recovery of the carrier reservoir of the QD's, however, leads to phase patterning which becomes evident after filtering of the converted signal with a delay interferometer, whose free spectral range is set to the bit rate. The phase patterning was mitigated by adjusting the delay interferometer to a large free spectral range. Moreover, the delay interferometer reinverted the converted signal and significantly enhanced the extinction ratio. Using such a wavelength converter scheme error-free (bit-error ratio < 10 -9 ) performance was achieved for
[Show abstract][Hide abstract] ABSTRACT: Single- and multi-channel amplifications using a quantum dot (QD) semiconductor optical amplifier (SOA) for data signals up to 80 Gb s−1 are investigated. A reach extension of 30 km for 40 Gb s−1 NRZ OOK data signals resulting in a total transmission distance of 75 km is presented. 80 Gb s−1 RZ OOK single-channel amplification demonstrates pattern-effect-free operation up to 6 dBm input power and 6 dB gain compression. Additional 40 Gb s−1 NRZ OOK interfering channels induce low crosstalk up to −6 dBm channel input powers (OSNR penalty below −3 dB at a BER of 10−9) proving the suitability for multi-channel booster amplification. Wavelength conversion via four-wave mixing is found to be feasible with less than 1 dB received power penalty at a BER of 10−9 for downconversion and is limited only by the achievable OSNR for upconversion. Using cross-gain modulation open eye diagrams are demonstrated for 80 Gb s−1 RZ OOK wavelength conversion. Therefore, QD SOAs demonstrate their suitability for a variety of applications in future all-optical ultra-high-speed networks toward 100 Gb s−1.
Semiconductor Science and Technology 11/2010; 26(1):014009. · 1.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Error-free booster amplification in a 4-mm QD-SOA has been achieved with 1-dB OSNR-penalty up to +15dBm output power for single-channel 80-Gb/s RZ-OOK signals and up to +8.3dBm for 4-channel multi-wavelength (80-Gb/s RZ-OOK + 3 × 40-Gb/s NRZ-OOK) signals on a 5-nm grid.
Optical Communication (ECOC), 2010 36th European Conference and Exhibition on; 10/2010
[Show abstract][Hide abstract] ABSTRACT: Optical parallel processing enables electronic dispersion compensation in coherent receivers at symbol rates above the employed electronics' speed limit. Up to 64 Gbaud QPSK (128 Gb/s) are processed and transmitted up to 610 km-SSMF without optical dispersion compensation.
Optical Fiber Communication (OFC), collocated National Fiber Optic Engineers Conference, 2010 Conference on (OFC/NFOEC); 01/2010