5 Gbit/s Full-Duplex Radio-Over-Fiber Link With Optical Millimeter-Wave Generation by Quadrupling the Frequency of the Electrical RF Carrier

Electro-optic up-conversion mixer amenable to photonic integration

“…Amongst various techniques to optically generate mm-wave signals, single side-band (SSB) modulation is preferred mainly because of the efficient elimination of the fading effect while transporting the generated mm-wave to the remote unit [1]. The implementation of SSB on architectures utilizing single and multiple Mach-Zehnder modulators (MZM) have been intensively investigated [2][3][4][5][6][7]. To minimize trimming, it has been advantageous in integrated circuits to exploit phase shifts that are intrinsic to the topology of the optical and electrical waveguides, as for instance, the π/2 phase shift between the arms of a 3 dB coupler and more generally the phase relations due to the self-imaging principle in multi-mode interference couplers (MMIs) [8,9].…”

“…A common approach at the remote unit has been to down-convert the mm-wave to baseband using electrical mixers and low-pass filters. The base-band signal is then used to modulate the intensity of an optical carrier and sent to the central office [3]. In another approach, an architecture comprising of a customized 100 GHz traveling wave electro-absorption modulator (EAM) is used to amplitude modulate a distributed feedback (DFB) laser externally [15].…”

A Novel Architecture of Millimeter-Wave Full-Duplex Radio-Over-Fiber System With Source-Free Bs Based on Polarization Division Multiplexing and Wavelength Division Multiplexing

“…In the BS, the Ypolarized light carrier is extracted using PBS to carry the uplink signal. Compared with the study in [12,14], since the optical carrier for the uplink does not carry the downlink signal, the crosstalk from the downlink does not contaminate the uplink signal. At the BS, it is detected by a high-speed photoelectric diode (PD) to generate a 15 GHz intermediate frequency (IF) and a 63 GHz radio frequency (RF) signal.…”

“…Since the two-color optical millimeter-wave signal with one tone can eliminate the RF power fading effect and displacement effect caused by fiber dispersion [8], single-sideband (SSB) optical modulation is considered to be a potential modulation scheme for generating optical millimeter-wave signals [9,10]. In addition, in order to simplify the base station (BS) of the full-duplex link, the upstream optical carrier is extracted from the downlink optical signal by optical filtering [7,[11][12][13][14][15] to propose and implement a passive BS or a semiconductor optical amplifier (SOA), the downlink information is erased, and the uplink data directly modulated on the downlink optical signal [16].…”

A cost-effective ROF system employing FBG and DML to generate optical mm-wave

“…To reduce the total cost and make simpler configuration of the ROF system sand connect as many users as possible, novel schemes of wavelength reuse or centralized light-waves in the CO have been proposed and experimentally demonstrated in [6][7][8][9]. To realize optical millimeter-wave generation, many techniques have been reported, such as the frequency up-conversions using four-wave mixing [10], cross-gain modulation in a semiconductor amplifier [11][12][13], and frequency doubling using optical carrier suppression modulation [14][15].…”