All-optical Frequency Up-conversion Research Articles

All-optical frequency upconversion for radio-over-fiber applications based on cross-gain modulation and cross-polarization modulation in a semiconductor optical amplifier.

We propose a novel all-optical frequency upconversion technique for radio-over-fiber (RoF) systems based on cross-gain modulation (XGM) and cross-polarization modulation (XPolM) in a semiconductor optical amplifier (SOA). A local oscillator signal is carried onto a continuous wave probe beam with orthogonally polarized single-sideband (SSB) modulation using a polarization modulator and a tunable optical filter. The intermediate frequency signal carried by a pump beam is only intensity modulated onto the sideband of the probe beam while the carrier of the probe beam is unmodulated thanks to the joint use of the XGM and XPolM effects in the SOA. This SSB upconversion scheme is inherently free from the chromatic-dispersion-induced power fading after transmission over single-mode fiber. The proposed scheme is theoretically analyzed and experimentally verified.

All-Optical Frequency Up-Converter Utilizing Cross Polarization Modulation in an SOA for 60-GHz-Band Radio-Over-Fiber Systems

A broadband all-optical frequency up-converter using cross polarization modulation in a semiconductor optical amplifier is proposed and experimentally demonstrated. Error-free transmission of 1.25 Gb/s pseudorandom bit sequence data with an optical RF signal (fRF=60 GHz) was achieved. The receiver sensitivities at a bit error rate of 10-9 were -12.16 and -9.6 dBm in the inverted and noninverted modes, respectively. This all-optical frequency up-conversion technique showed negligible power penalties for fiber length up to 29.6 km.

Local Oscillator Free Frequency Up-Conversion at Millimeter-Wave Band

We have demonstrated all-optical frequency upconversion at millimeter-wave band without using local oscillators. By launching a low bit rate signal into a Fabry-Perot laser diode (FP-LD), a microwave subcarrier is generated based on the four wavelength mixing and injection mode locking. Due to the dynamic charge carrier density response during the injection locking, the wavelength of the leading part of the subcarrier will be red-shifted while that of the falling part will be blue-shifted. By compensating the generated chirp with a suitable negative dispersion device, the time-domain pulses will be compressed and the second harmonic of the subcarrier will be generated. A polarization interferometer is used to further suppress the foundational frequency. In our experiment, a subcarrier of 30.8 and 34.8 GHz is obtained by launching a 2.5-Gb/s NRZ signal into the FP-LD. We also show that the photonic frequency upconversion can go up to ~60 GHz with the proposed scheme.

Simultaneous generation of WDM RoF signals in an all-optical frequency upconverter utilizing a semiconductor optical amplifier

All-optical frequency upconversion utilizing a semiconductor optical amplifier (SOA) is experimentally demonstrated. Eight optical radiofrequency (RF) signals having the RF frequency of 26.5 GHz are simultaneously generated by four-wave mixing in the SOA. Power penalties for simultaneous generation of eight optical RF signals are less than 1.1 dB. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2420–2422, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27048

All-optical frequency upconversion of a quasi optical single sideband signal utilizing a nonlinear semiconductor optical amplifier for radio-over-fiber applications

An all-optical frequency upconversion technique using a quasi optical single sideband (q-OSSB) signal in a nonlinear semiconductor optical amplifier (NSOA) for radio-over-fiber applications is proposed and experimentally demonstrated. An optical radio frequency signal (f(RF) = 37.5 GHz) in the form of a q-OSSB signal is generated by mixing an optical intermediate frequency (IF) signal (f(IF) = 2.5 GHz) with an optical local oscillator signal (f(LO) = 35 GHz) utilizing coherent population oscillation and cross gain modulation effects in an NSOA. The phase noise, conversion efficiency, spurious free dynamic range (SFDR), and transmission characteristics of the q-OSSB signal are investigated.

Simultaneous WDM RoF Signal Generation Utilizing an All-Optical Frequency Upconverter Based on FWM in an SOA

A simultaneous all-optical frequency upconversion technique using four-wave mixing in a semiconductor optical amplifier (SOA) is experimentally demonstrated for wavelength-division-multiplexing (WDM) radio-over-fiber applications. Eight WDM optical radio-frequency (RF) signals having the RF frequency of 26.5 GHz are simultaneously generated by mixing eight WDM optical intermediate-frequency (IF) signals having the IF frequency of 2.5 GHz with an optical local oscillator signal of 24 GHz in a single SOA. The power penalty for simultaneous generation of eight WDM optical RF signals at the bit-error rate of 10-9 is less than 2.7 dB.

Full-Duplex WDM-Based RoF System Using All-Optical SSB Frequency Upconversion and Wavelength Re-Use Techniques

We have experimentally demonstrated a full-duplex wavelength division-multiplexing-based radio-over-fiber system using all-optical single-sideband (SSB) frequency upconversion and wavelength re-use techniques for broadband optical-wireless access networks. The optical SSB RF signal having the RF frequency of 62.5 GHz is generated by using this all-optical frequency upconverter that consists of an arrayed waveguide grating for optical demultiplexing and a semiconductor optical amplifier for wavelength conversion based on the cross-gain modulation effect. The receiver sensitivity at the bit error rate of is 11.5 and for downlink (including air transmission of 1.5 m) and uplink, respectively. The power penalties originating from the fiber chromatic dispersion are negligible after transmission over 25-km standard mode fibers (SMFs) for both downlink and uplink. For the IF wavelengths from 1530 to 1580 nm (covering -band), the variation of the receiver sensitivity is less than 2.5 dB.

A Novel and Tunable Frequency-Upconversion Based on FP-LD Injection of One Low Bit-Rate Signal Without Any RF Local Oscillator

An all-optical frequency-upconversion is presented by injecting a low bit rate signal into a Fabry-Perot laser diode (FP-LD) without any radio-frequency local oscillator. One of the FP-LD lasing modes is locked by generated sideband through four-wave-mixing effect in FP-LD. The generated microwave subcarrier could be tunable by varying the power and polarization of the injected signal. The input signal at the data rate of 1.25, 2.5, and 2.7 Gb/s with nonreturn-to-zero format are upconverted to a subcarrier modulation signal at upcoversion frequencies of 20, 10, and 16.2 GHz, respectively. The single sideband phase noise of -81.2 and -87.7 dBc/Hz (10-kHz frequency deviation) at 16.2-GHz subcarrier are demonstrated. The difference of sidemode suppression ratio at the FP-LD output point is also analyzed.

BER and SFDR Characteristics of an FWM-Based All-Optical Frequency Upconverter

We have experimentally investigated the bit-error-rate (BER) and spurious-free dynamic range (SFDR) characteristics of an all-optical frequency upconverter based on the four-wave-mixing effect in a semiconductor optical amplifier for radio-over-fiber networks. The generation and error-free transmission of an optical radio-frequency signal having 155.52-Mb/s differential phase-shift keying data at a carrier frequency of 26.5 GHz are achieved. The dynamic ranges of an optical intermediate frequency (IF) input signal estimated from the BER and SFDR measurements are approximately 12 and 16 dB, respectively. The SFDR of the upconverter is larger than 77 dBmiddotHz2/3 for the IF frequencies ranging from 1 to 12 GHz.

Generation of 60-GHz MB-OFDM Signal-Over-Fiber by Up-Conversion Using Cascaded External Modulators

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, we demonstrate multiband orthogonal frequency division multiplexing (MB-OFDM) transmission of quadrature phase shift keying (QPSK) modulation with 200-Mb/s bit rate by all-optical frequency up-conversion using external modulator for ultrawideband (UWB) applications to 60-GHz band radio-over-fiber (RoF) network. Error vector magnitude (EVM) measurements are used to evaluate the performance of our system and an EVM root mean square (rms) of 12.6% at 60 GHz is obtained with our technique and corresponds to bit error rate (BER) below <formula formulatype="inline"><tex Notation="TeX">$10^{-9}$</tex></formula>, in compliance with standard requirements. </para>

Optical Distribution and Upconversion of MB-OFDM in Ultrawide-Band-Over-Fiber Systems

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Broadband radio-over-fiber networks are raising great interest for intrabuilding distribution and signal processing of ultrawide-band (UWB) signals. In this paper, a unique optical system based on an external modulator biased either in linear or nonlinear regime has been used to realize both distribution of multiband orthogonal frequency-division multiplexing (MB-OFDM) UWB signal and all-optical frequency upconversion of UWB-OFDM subband. The impact of the nonlinearity of the optical link on the MB-OFDM signal is investigated through a simulation model of the complete UWB-over-fiber system. Results have shown enhanced performance of upconverted MB-OFDM subband compared to direct transmission due to optical noise reduction. First experimental results have confirmed simulation results. </para>

光纤无线通信系统中用高非线性光纤实现全光频率上转换

光纤无线通信系统中用高非线性光纤实现全光频率上转换

Optical Frequency Conversion for Millimeter-Wave Ultra-Wideband-Over-Fiber Systems

This letter investigates all-optical frequency conversion of ultra-wideband (UWB) signals for UWB-over-fiber up-link and down-link systems. An electrooptical Mach-Zehnder modulator is used in nonlinear regime to realize frequency up and down conversion of UWB rectangular pulse and monocycle. All-optical frequency up-conversion of rectangular pulse at 18 GHz generates undesired local oscillator centered in the up-converted UWB spectrum, whereas up-conversion of monocycle waveform exhibits a power spectrum density optimally fitting the UWB emission mask. Up and down conversions of UWB monocycle, using the same UWB-over-fiber system, have shown low distortion induced by the optical mixing process on the UWB monocycle.

4×2.5-Gbit∕s all-optical frequency upconversion using nonlinear polarization rotation in highly nonlinear fiber for radio over fiber

We experimentally demonstrate 4×2.5-Gbit/s all-optical frequency upconversion at 20 GHz, based on nonlinear polarization rotation in a highly nonlinear fiber. The demodulated signals are analyzed.

Harmonic Millimeter-Wave Generation and Frequency Up-Conversion Using a Passively Mode-Locked Multisection DFB Laser Under External Optical Injection

We demonstrate that a passively mode-locked multisection distributed-feedback (PML-MS DFB) laser can perform both harmonic millimeter-wave generation and harmonic frequency up-conversion under the external optical injection. Optical multiple modes generated by a PML-MS DFB laser produce harmonic millimeter-waves by mode-beating in a photodiode (PD), and the phase quality and stability are enhanced by the injection of external optical signal modulated at f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LO</sub> . In addition, if the external optical signal is modulated simultaneously by f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LO</sub> and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IF</sub> , the PML-MS DFB laser performs all-optical frequency up-conversion producing sidebands at f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LO</sub> plusmnf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IF</sub> when detected by a PD. Using this method, we demonstrate generation of stable harmonic millimeter-waves at 30.42 and 60.84 GHz with f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LO</sub> of 15.21 GHz, and up-conversion of 10-Mb/s quadrature-phase-shift keying data at 150 MHz f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IF</sub> into the 60-GHz band. These functions of a PML-MS DFB laser can be useful for radio-over-fiber applications in which a compact optical source is needed for processing high-frequency radio signals in optical domain

All-optical frequency up-conversion for WLAN over fiber applications

This paper investigates up-conversion of a 54-Mb/s 802.11a WLAN signal in a radio-over-fiber (RoF) link. The frequency conversion is realized using either a DFB laser diode or an electro-optical modulator (EOM) (both biased in nonlinear regimes). Very low error-vector magnitude (EVM) measurements are reported at minimum of transmission of electro-optical modulator for a large 802.11a input power range, and an acceptable EVM degradation is obtained using the cost-effective LD mixing technique, but with a limited input power range. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 421–424, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21369

All-optical frequency upconversion of radio over fibre signal with optical heterodyne detection

An all-optical frequency upconversion of radio over fibre signal with an optical heterodyne detection that is based on the cross-phase modulation effect in a semiconductor optical amplifier is proposed. Optical IF signal that contains 155.52 Mbit/s differential phase shift keying signal at 2.5 GHz along with 24 GHz optical LO signal are transmitted over a 20 km-long singlemode fibre and then frequency upconverted to 26.5 GHz at a remote base station by using an SOA Mach-Zehnder interferometer. Error-free frequency upconversion is experimentally demonstrated.