# The Multiband over Spatial Division Multiplexing Sliceable Transceiver for Future Optical Networks
## 5 Setup Implementation and Proof-of-Concept  
For the proof-of-concept assessment of the MB(oSDM) S-BVT, 3 different slices working at the S-, C-, and L-bands are enabled, as depicted in Figure 5. Specifically, adaptive modu  
Figure 4: XT analysis over different MCF lengths and considering MB transmission in the O-, E-, S-, C-, L-, and U-bands.  
Figure 3: Estimated XT versus wavelength in a trench\(-\)assisted 19\(-\)cores MCF of 25.4 km.  
lation based on the Levin-Campello loading algorithm is performed at each transceiver building block, to flexibly adapt the modulation format and power value per subcarrier according to the channel profile [22]. After performing the different DSP operations described in Section 3, a high-speed DAC at 64 GSa/s is used to generate an OFDM electrical signal of 512 subcarriers and 20 GHz bandwidth. The transceiver front-end is based on external modulation and includes an array of lasers, that can be set up within the S-, C-, and L-bands, and MZMs working at the quadrature point. In particular, an electro-absorption modulated laser (EML) set to 1500 nm is used for the S-band contribution with 150 kHz linewidth. 2 TLSes at 1550.12 nm and 1600 nm are used for the C- and L-bands with linewidth values \(<\) 100 KHz and equal to 500 kHz, respectively. The output power of the three contributions are set to 10 dBm. A MB high-capacity flow is created by means of an optical aggregator, which includes single side band (SSB) filters and a BPF. SSB modulation is implemented within the C- and S-band slices, by including a wavelength selective switch (WSS) of 25 GHz bandwidth and a tuneable filter (TF) of 30 GHz bandwidth, respectively. This increases the resiliency against chromatic dispersion, enhancing overall performance. However, due to laboratory/setup limitations, the L-band contribution is not filtered and a DSB signal is aggregated with the other contributions. The transmitted MB high-capacity flow can be seen in Figure 6, as well as the detailed S-, C-, and L-band spectra.  
At the receiver side of the proposed MB(oSDM) S-BVT, an optical distributor is included, based on a BPF. The different slices are distributed to the corresponding bandwidth/bitrate variable receivers (BVRxs), adopting specific components/technology capable to operate in a particular band. Specifically, an EDFA (operating at automatic power control mode) and a WSS for amplified spontaneous emission (ASE) noise filtering (centred at 1550.12 nm and 50 GHz bandwidth) are used at the receiver front-end, for the C-band contribution. The S-band slice is amplified with a TDFA (operating at automatic current control mode) and filtered with a static filter, whereas an EDFA (operating at auto current control mode) and a static filter are considered at the L-band. All the contributions are photodetected with different PINs and ADC converted with an oscilloscope at 100 GSa/s. Additional DSP and performance parameters (summarized in Table 1) have been considered for the experimental assessment of Section 6.  
Figure 5: Experimental setup illustrating an S\(-\)BVTx at node 1 (S\(-\)BVTx1) and an S\(-\)BVRx at node 2 (S\(-\)BVRx2).