High-Capacity Wireless Signal Generation and Demodulation in 75- to 110-GHz Band Employing All-Optical OFDM

Abstract

We present a radio-frequency (RF) and bit-rate scalable technique for multigigabit wireless signal generation based on all-optical orthogonal frequency-division multiplexing (OFDM) and photonic up-conversion. Coherent detection supported by digital signal processing is used for signal demodulation and data recovery. In order to demonstrate the RF frequency scalability and bit-rate transparency, the system is tested at 60 GHz and in the 75-to 110-GHz band at the baud rates of 5 and 10 Gbaud. In terms of the bit rate, the proposed system is experimentally tested up to 40 Gb/s for wireless signal generation and demodulation. The wireless transmission is not considered in this letter. Additionally, a novel digital carrier phase/frequency recovery structure is employed to enable robust phase and frequency tracking between the beating lasers.

100 Gbit/s hybrid optical fiber-wireless link in the W-band (75–110 GHz)

“…Analog-to-digital conversion is performed by an 80 GS/s real-time digital sampling oscilloscope (DSO, Agilent DSAX93204A) with 32 GHz analog bandwidth. Offline signal demodulation is performed by a DSP-based receiver, consisting of frequency down conversion, I/Q separation, carrier recovery and filtering, equalizer, symbol decision and BER tester [10]. Figure 4a and Figure 4b shows the electrical spectra of the received IF signal and the signal after digital down-conversion and low pass filtering with cutoff frequency of 0.75×baud rate, respectively.…”

“…(6) we can see that the transmitted baseband signal I(t) + jQ(t) can be recovered at the DSP receiver. The accumulated phase offset and phase noise during transmission is contained in the term φ IF (t), which can be later corrected in DSP [10]. Maximum value of the RF signal power is achieved when the polarization statesê s andê c are aligned.…”

“…Most recently, 40 Gbit/s 16-level quadrature amplitude modulation (16-QAM) wireless transmission in the W-band is presented [9]. We have previously demonstrated 40 Gbit/s signal generation in the W-band by employing photonic up-conversion of all-optical frequency division multiplexed (OFDM) QPSK signals, with detection performed by photonic down conversion supported by digital coherent demodulation [10]. Regarding achieved air transmission distances for bit-rates above 20 Gbit/s in the W-band, so far 20 cm for 20 Gbit/s ASK transmission [5] and 3 cm for 40 Gbit/s 16-QAM transmission [9] are reported.…”

42.13 GBIT/S 16QAM-OFDM PHOTONICS-WIRELESS TRANSMISSION IN 75-110 GHz BAND

“…In these reported 60 GHz band and W-band schemes, hybrid photonic-electronic up-conversion (coherent method) is used to generate the high wireless carrier frequency, and 2.5 m wireless transmission with achieved performance slightly above the forward error correction (FEC) limit in [11] and 30 mm wireless transmission with achieved performance below the FEC limit in [13,14] are demonstrated. Recently, a photonic up/down-conversion (incoherent method) with RF/bit-rate transparency has also been proposed for a 40 Gbit/s OFDM W-band system without air transmission [15]. The wireless transmission demonstration of very high speed OFDM Wband signals will therefore contribute to the needed development of ultra-broadband wireless communication technology.…”

Experimental demonstration for 40-km f iber and 2-m wireless transmission of 4-Gb/s OOK signals at 100-GHz carrier

“…However, many of research findings concentrate on using high spectral efficient data formats to transmit more data per symbol [6−10] , making the transmitter and receiver complex and real-time system difficult to build up. In addition to improving the 100-GHz RoF system's performance, coding [8] or equalization [9,10] is also proposed in some reports. Thus, simplicity and practical applications for the RoF technology are still problems should be addressed.…”