Carrier Suppression Technique Research Articles

Large Tunable 16-Tupled Millimeter Wave Generation Utilizing Optical Carrier Suppression With a Tunable Sideband Suppression Ratio

Coping up with the rising bandwidth demands for 5G ultra-high speed applications, utilizing millimeter (MM) wave spectrum for data transmission over the radio over a fiber-based system is the ideal approach. In this study, a highly conversant and spectrally pure photonic generation of a 16-tupled MM wave signal using a series-connected DD-MZM with a lower modulation index, a splitting ratio, and a wider tunable range is presented. A 160-GHz MM wave is generated through a double sideband optical carrier suppression technique having an optical sideband suppression ratio (OSSR) of 69 dB and a radio frequency sideband suppression ratio (RSSR) of 40 dB. However, the OSSR and the RSSR are tunable with values greater than 15 dB when the modulation index (M.I.) varies from 2.778 to 2.873, ±8° phase drift, and a 15-dB enhancement in the OSSR with a wider nonideal parameter variation range giving acceptable performance can be seen in the model as compared with previous research works.

Modulation Index and Phase Imbalance of Dual-Sideband Optical Carrier Suppression (DSB-OCS) in Optical Millimeter-Wave System

This paper presents a Dual-sideband Optical Carrier Suppression (DSB-OCS) technique which is used to generate an optical millimeter-wave (mm-wave) signal in radio over fiber (RoF) systems. The proposed system employs a Dual-Electrode Mach-Zehnder Modulator (DE-MZM) and a carrier of 40 GHz mm-wave for data transmission through the RoF systems. Characteristics determining the performance of the system, among which are the modulation index, phase imbalance and dispersion parameters, are included. The performance evaluations of the system show that the mm-wave signal output power follows MZM’s transfer function when the modulation index is raised. Moreover, the generated optical mm-wave signal power is affected by phase imbalance and optical splitting ratio. It is observed that the optical fiber dispersion influences the DSB-OCS system by decreasing the amplitude of the mm-wave and the signal-to-noise ratio (SNR).

Photonic generation and theoretical investigation of phase noise in quadrupling and 12-tupling millimeter wave Signal using optical self-heterodyne system

In this paper, photonic generation of quadrupling and twelve-tupling millimeter wave signal using single radio frequency (RF) signal is proposed. The purity of generated signal is observed by using mathematical approach which is further verified on simulation platform. Cascaded DP-DDMZM configuration is used in the proposed optical self- heterodyne system to generate millimeter-wave signals four times and twelve times the input RF source frequency. Selective sideband generation and carrier suppression techniques are utilized to generate the desired RF signal at the photodetector. Furthermore, the phase noise analysis of the generated millimeter wave signal is theoretically investigated. Expression of power spectral density for 40 GHz and 120 GHz millimeter signal is mathematically calculated to observe how the spectral quality is affected by the random phase fluctuations of input RF and optical sources. Phase noise of the millimeter-wave signal for different optical path length difference at various offset frequency is compared and discussed. System parameters such as noise figure, insertion loss, and spurious-free dynamic range (SFDR) are calculated for generated millimeter-waves/RF signals. The present proposed system uses a single RF source to generate quadrupling and 12-tupling millimeter wave and find its application in WDM systems, optical signal processing, radar system, etc. The results can be used to build an opto-electronic oscillator for a high-frequency microwave photonic communication system.

Experimental demonstration of all-optical PolMux RoF system with multiservice transmission

In this paper, a Radio-over-Fiber (RoF) system is proposed by combining optical carrier suppression (OCS) and polarization multiplexing (PolMux) techniques in all-optical mode to enable multi-service transmission. Previous studies on RoF system only exploited multi-service transmission over low radio frequency (RF) oscillator-based PolMux, subcarrier multiplexing (SCM) and wavelength division multiplexing (WDM) techniques. Hence, herein, PolMux jointly with OCS techniques are exploited as a new medium of multiplexing in RoF system. Essentially, two contributions are unveiled, firstly the combination of all optical OCS and PolMux for RoF technology to enable multi-service transmission, and secondly an end-to-end all-optical transmission with the inclusion of wireless medium at millimeter wave (mmWave) frequency. The results indicate a highly reliable OCS-PolMux topology, where the EVM deterioration due to polarization leakage factor was only ∼1% to ∼2% for both services transmitted at the same frequency. Most importantly, the proposed system demonstrated an end-to-end system transmission with optical receiver power budget of up to ∼6 dB.

The Improved Optical Heterodyne Scheme for RoF Systems Based on Optical Carrier Suppression and Optical Injection Locking Techniques

Abstract In this paper, we proposed an improved optical heterodyne scheme based on optical carrier suppression (OCS) and optical injection locking techniques (OIL) for prospective applications in radio-over-fiber (RoF) systems to generate high-quality millimeter waves. In our scheme, the 60-Ghz millimeter wave signal is generated by heterodyning the outputs of two vertical cavity surface emitting lasers (VCSELs) that are optically injection locked by the two modulation sidebands provided by a 30-GHz externally modulated master tunable laser with suppressed center wavelength. The combined OCS and OIL heterodyne method are not only able to eliminate the phase noise caused by the instability of laser frequencies, but also can further suppress the center wavelength, thus improving the heterodyne performance. We evaluate the transmission quality of the proposed RoF system from the center station to base stations through simulation, and results prove our proposed OCS-OIL-heterodyne scheme to have error-free propagation within a distance of 40 km, better than the OCS-heterodyne scheme.

2.44-GHz Surface Acoustic Wave Resonator Phase Noise Measured by Carrier Suppression Technique.

The phase noise of surface acoustic wave resonators is explored by a passive measurement system based on the carrier suppression technique. The measurements are focused on 2.44-GHz quartz crystal resonators. These resonators are characterized in terms of motional parameters. The power dissipated through the resonators is around [Formula: see text]. The second-order frequency-temperature coefficient of the resonators has been measured to be around -0.038 ppm/°C2 that corresponds to a classical ST cut. The resonator conditioning is presented. The measured noise exhibits a 1/ f frequency fluctuation behavior. The short-term stability (flicker floor) is given in terms of Allan standard deviation. The order of magnitude is around 2×10-10 . Additional measurements are given for resonators at 433 and 915 MHz in order to compare them. The results are presented according to the intrinsic quality factor of the resonators and compared to the previous works done in the past by T. Parker. These additional data provide valuable information on the dependence of the flicker noise levels on resonator frequency.

Selective delivery of broadband wireless and wired services in an integrated ROF-PON system using dual-sideband optical carrier suppression

Selective delivery of gigabit-per-second wireless and wired services is demonstrated in an integrated fiber-wireless access network using the millimeter-wave (mm-wave) radio-over-fiber (RoF) system employing the dual-sideband optical carrier suppression technique. A dual-electrode Mach-Zehnder modulator is used in this technique to generate 40 GHz carrier to distribute 1.25 Gbps data via direct modulation (DM) over a 20 km RoF system. The results show that selective signal delivery can be achieved using a low-cost DM laser diode drive current of 20 mA. The advantage of the proposed system is that it provides versatility to control the gigabit-per-second (Gbps) signal delivery in an integrated ROF-PON system with a common high frequency oscillator shared for the whole system. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1768–1773, 2016

Centrally controlled self-healing wavelength division multiplexing passive optical network based on optical carrier suppression technique

We proposed and demonstrated a centrally controlled and self-healing wavelength division multiplexing passive optical network with colorless optical network units (ONUs) based on optical carrier suppression technique. By switching the affected data in the OCS signal sideband to an alternate protection path, only one optical switch is provisioned at the optical line terminal, which is controlled by a logic control circuit upon monitoring of power outage on the working path. The proposed scheme can reliably protect against both distribution and feeder fiber failures. Moreover, gain-saturated reflective semiconductor optical amplifiers are used as colorless transmitters in ONUs. The protection scheme feasibility and system performances are experimentally verified with 10 Gb/s downstream and 1.25 Gb/s upstream data in both working and protection modes. The protection switching time was measured to be around 1 ms.

A novel OFDM-ROF system based on OCS and asymmetrical filtering technique

A novel radio-over-fiber (ROF) system has been proposed and simulated, which is based on orthogonal frequency division multiplexing (OFDM) and asymmetrical filtering of optical carrier suppression (OCS) technique, so it can effectively suppress the fading effect caused by power periodic variation in traditional OCS system. Simulation results show that the 2.5 Gbit/s OFDM-modulated wideband wireless signal can be transmitted over 25 km single mode fiber (SMF) successfully.

40-GHz ROF downlink system with SFP modules

40-GHz radio over fiber (ROF) downlink system is constructed with the dual-sideband optical carrier suppression technique using Mach–Zehnder modulator. Small form pluggable (SFP) module is used as the optical source at the central station. 1.25-Gbps data are directly modulated into the system via laser diode at the SFP. Several SFP modules are evaluated for their performance to be used in this system. The results show that all the SFP modules have shown their highest capability up to the bit error rate of 10−9 with about 1-dB power penalty to realize the 20-km error free 40-GHz ROF downlink system. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:900–903, 2014

High conversion efficiency microwave photonic mixer based on stimulated Brillouin scattering carrier suppression technique

A new microwave photonic mixer that can achieve a high conversion efficiency is presented. It is based on using the stimulated Brillouin scattering loss spectrum to suppress the optical carrier at the output of two optical phase modulators driven by the RF signal and the LO, respectively. Experimental results are presented, which demonstrate a high conversion efficiency of 11.3 dB corresponding to over 26 dB improvement compared to the conventional dual-series Mach-Zehnder modulator based microwave photonic mixer, and wide bandwidth of 0.2 to 20 GHz mixing operation.

Survivable wavelength-division multiplexing passive optical network system with centralized protection routing scheme and efficient wavelength utilization

A survivable wavelength-division multiplexing passive optical network (WDM-PON) with centralized protection scheme and colorless optical network units is proposed. The sideband channels generated via optical carrier suppression technique are used to carry both the downstream (DS) and the upstream (US) remodulated signals for two neighboring sub-PONs. By employing alternate path routing of sideband channels, the centralized protection scheme can provide reliable protection against any failure in feed fibers, remote node, and distribution fibers. The number of extra fibers is greatly reduced, and efficient utilization of wavelength resource is achieved. The feasibility of the proposed system is verified by 10-Gb/s DS and 1.25-Gb/s US signals over 25-km single-mode fiber transmission in both working and protection modes.

On the carrier generation and HD signal transmission using the millimeter-wave radio over fiber system

The dual sideband optical carrier suppression (DSB-OCS) technique is employed in the optical carrier generation for 40GHz radio over fiber (ROF) system. A dual electrode Mach-Zehnder modulator (DE-MZM) with the minimum transmission bias (MiTB) technique is employed to build the system. The results show that, a 40GHz carrier is successfully generated with the amplitude up to −29dBm and signal to noise ratio (SNR) of 35dB and a high definition (HD) signal is successfully transmitted using the system. Finally, the bit error rate (BER) measurement is carried out for the system with 1.25Gbps OOK signal showing an error free 40GHz ROF system with almost no penalty between the back to back and 20km fiber for a BER of 10−9.

A Survivable WDM-PON Architecture Using Optical Carrier Suppression Technique

In this paper, we propose and demonstrate a novel survivable WDM-PON architecture using Optical Carrier Suppression (OCS) technique. It can provide protection against the feeder fiber failure. The simulation results for the scheme at 2.5 Gbit/s downstream signals and 2.5 Gbit/s upstream signals are presented to verify the feasibility of system.

Efficient Delivery of Integrated Wired and Wireless Services in UDWDM-RoF-PON Coherent Access Network

A high-capacity coherent ultradense wavelength-division multiplexing passive optical network integrated with a 60-GHz radio-over-fiber system has been designed and experimentally demonstrated for the first time. In this proposed architecture, millimeter-wave signal generation is achieved by coherent technology, in place of the optical carrier suppression technique, which requires modulators with large bandwidth and precise optical interleavers. The system fully exploits advantages of coherent access networks to provide both multigigabit wired and wireless access services with high spectral and power efficiencies. Successful wireless transmission of multichannel 3.3-Gb/s quadrature phase-shift keying signals with 10-GHz channel spacing over 50-km single-mode fiber (SMF-28) has been achieved.

A Centrally Controlled Survivable WDM-PON Based on Optical Carrier Suppression Technique

A simple centrally controlled survivable wavelength-division-multiplexed passive optical network (WDM-PON) architecture employing an optical carrier suppression technique is proposed. Protection switching at the optical line terminal employs electrical switches to control the clock signal for the protection subcarrier generation, via optical carrier suppression. Both distribution and feeder fibers are protected simultaneously. By employing an inverse-return-to-zero format for the downstream transmission and nonreturn-to-zero for the upstream remodulated signal, the optical network units are kept colorless and simple. The 10-Gb/s transmissions under both normal working and protection modes were experimentally demonstrated and traffic restoration time was measured to be about 5 ms.

An optical multicast overlay scheme using optical sub-carriers for WDM passive optical networks

We propose to make use of optical sub-carriers to realize optical multicast overlay on a WDM passive optical network. By employing optical carrier suppression technique at each downstream optical transmitter at the OLT, two coherent optical sub-carriers are generated to carry the 10-Gb/s downstream unicast DPSK signal and the 10-Gb/s downstream multicast ASK signal, separately without any additional light sources. At the ONU, the 10-Gb/s upstream data is superimposed on the received downstream unicast DPSK signal, to form the upstream ASK signal. System characterization is performed to optimize the performance. In addition, we further demonstrate simultaneous optical overlay of two streams of multicast data in the network.

Improvement in the Phase Noise of a 10 GHz Optoelectronic Oscillator Using All-Photonic Gain

We have investigated the improvement in the phase noise of a 10 GHz optoelectronic oscillator using all-photonic gain as compared to using an electronic amplifier in the cavity. The optoelectronic oscillator achieves the necessary RF gain for oscillation by using the carrier-suppression technique of a low-biased Mach-Zehnder modulator (MZM) followed by optical amplification. The measured RF gain due to this all-photonic technique is as high as 15 dB and matches well with theoretical predictions. The phase noise of the generated 10 GHz signal is at least 10 dB lower than the signal from the same oscillator using an electronic amplifier. The improvement in the phase noise is due to the lower RF noise figure of the all-photonic gain process as compared to the electronic amplifier configuration.

Wavelength Conversion Based on Copolarized Pumps Generated by Optical Carrier Suppression

Polarization-insensitive wavelength conversion based on four-wave mixing for 112-Gb/s polarization- multiplexed return-to-zero quadrature phase-shift keying signals (PolMux-RZ-QPSK) with digital coherent detection is experimentally demonstrated. The dual-pumps always have the same polarization direction and fixed frequency spacing because they are generated by the optical carrier suppression technique. The conversion efficiency at different pumping powers and signal wavelengths has also been investigated. A tuning range of a signal wavelength of wider than 18 nm is realized with the same conversion efficiency in this proposed architecture. There is no obvious optical signal-to-noise ratio penalty for the converted 112-Gb/s PolMux-RZ-QPSK signals.

Employing mutually injection-locked FP LDs scheme over full-duplex radio-on-fiber transport systems

A full-duplex radio-on-fiber (ROF) transport system based on mutually injection-locked Fabry-Perot laser diodes (FP LDs) as light source is proposed and demonstrated. Transmission performances over a 40-km standard single-mode fiber (SMF) for full-duplex transmission were investigated. Good performance of bit error rate (BER) was achieved in our proposed systems. We directly modulate the FP LDs in mutually injection-locked scheme instead of using expensive external modulator and sophisticated optical carrier suppression technique; it reveals an outstanding alternative with advantages in simplicity and cost.