In this paper, a full duplex Millimeter Wave (mm-wave) enabled Radio-over-Fiber (RoF) architecture is proposed for Distributed Antenna Systems (DAS). This architecture is capable of achieving transmission of 16 × 16 optical Multiple Input Multiple Output (MIMO) spatial streams at 12 Gbps per spatial stream by employing Wavelength Division Multiplexing (WDM) and exploiting its other degrees of freedom such as polarization states and modes of wavelengths. A single laser source based multi-wavelength comb and wavelength reuse techniques along with Plastic Optical Fiber (POF) are employed to make the proposed architecture cost efficient.Optical heterodyne detection is performed at the Radio Access Unit (RAU) to generate mm-wave carrier frequency at 60 GHz. Channel equalization is achieved for Pulse Amplitute Modulation (PAM-4) data signal by employing Least Mean Square (LMS) equalizer to mitigate the optical fiber channel effects. Our proposed system supports 16 × 12 Gbps for Downlink (DL) and Uplink (UL) transmissions. To evaluate the performance of the proposed system, we compare the receiver sensitivities at FEC limit of 3.8 × 10 −3 of Bit Error Ratio (BER) of Back to Back (B2B) system, employing no fiber effects, with its counterparts. We show that acceptable power penalties for the fiber lengths of 200 meter and 400 meter are achieved for both LP01 and LP11 modes in DL and UL directions.

In this paper, we propose a full duplex architecture based on a hybrid link composed of free space optics (FSO) and multimode plastic optical fiber (MMPOF) for short-range wireless access networks. The proposed architecture employs mode group division multiplexing (MGDM) and wavelength reuse techniques to transmit data between central unit (CU) and radio access units (RAUs). An optical frequency comb source to generate multiple optical sidebands is realized using a single laser source to provide 60 GHz millimeter-wave (mm-wave) signals at each RAU by simultaneously transmitting PAM-4 signal on linearly polarized (LP) modes of each optical sideband. Data rate of 2$$\times$$ × 12 Gbps at mm-wave frequency of 60 GHz is achieved for both downlink (DL) and uplink (UL) transmissions. The transmission of 2$$\times$$ × 12 Gbps PAM-4 signal over hybrid FSO-MMPOF link is investigated at different values of refractive index structure parameter ($$C_n^2$$ C n 2 ) by employing log-normal (LN) FSO channel model to support three RAUs in a ring topology. The acceptable receiver sensitivities below −5 and −0.6 dBm for DL and UL transmissions are achieved, respectively. The proposed hybrid architecture can be a potential candidate for future communication networks.

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This Letter proposes a high data rate optical transmission system for data centre interconnects, where the authors employ vertical cavity surface emitting lasers (VCSEL) and graded index few‐mode fibre (GI‐FMF) having modal bandwidth of around 24.3 GHz.km to enhance the link capacity and range. Additionally, they consider PAM‐4 modulated data transmission at the rate of 2 × 100 Gbps using a pair of VCSELs and employing mode group division multiplexing of two linearly polarised (LP) modes normalLP01 and normalLP11 of the GI‐FMF. Digital signal processing techniques are applied at the receiver to process the received PAM‐4 signals for equalisation in order to mitigate the channel impairments. Furthermore, standard OM3 and OM4 fibres are considered as a benchmark to compare the transmission performance of the designed GI‐FMF. They observe that the designed GI‐FMF supports longer transmission distance for both normalLP01 and normalLP11 modes upto 900 and 450 m at 50 and 100 Gbps data rates, respectively, while achieving lower receiver sensitivities for forward error correction limit of 3.8×10−3. The proposed optical transmission system can be a potential applicant in future data centre networks supporting transmission rates in 800 Gbps to 1.6 Tbps range.