Error-free Wavelength Conversion Research Articles

Wavelength conversion using fiber cross-phase modulation driven by two pump waves.

Wavelength conversion using all-optical phase modulation in a fiber driven by two pump waves is investigated. The operation features are analyzed using an all-optical phase modulation model with two parallel-/cross-polarized pump waves to generate a phase-preserving copy of the optical signal at an exact frequency up-/down-shifted by the two-pump detuning. The conversion efficiency is experimentally verified using a 300-m highly-nonlinear fiber. The results agree well with a theoretical prediction. The conversion bandwidth over 4 THz is achieved and error-free wavelength conversion for a 32-GBd polarization-division multiplexed 16QAM signal is demonstrated. The technique's applicability to a large-capacity wavelength-division multiplexed signals is also discussed.

Cross polarization modulation based wavelength conversion with very low pump power in SOA: An investigation

An efficient wavelength converter is presented here which uses cross polarization modulation inside an optimized semiconductor optical amplifier. A contra propagation configuration is implemented with very minimal power pumping technique. This approach is exploited for a higher bit rate of 80 Gbps with minimum pump power of −4 dBm. The potential for all optical wavelength conversion is then assessed through characterization of the dynamics of the state of polarization along with the effect of pump power. As a result, a clear open eye for error-free wavelength conversion with appreciable quality factor of 12.73 and minimum logarithmic of bit error rate of −33.8 are obtained.

Monolithically Integrated Wavelength Converter for Intra-Data Center Routing Applications

A wideband wavelength converter based on cross gain modulation has been demonstrated by using a monolithically integrated semiconductor optical amplifier and 12-channel distributed feedback lasers. Error-free operation unicast wavelength conversion of 10-Gb/s non-return-to-zero ON–OFF keying data payload has been demonstrated with 3-dB power penalty and around 0.5 dB extra penalty for transmission over 2-km single-mode fiber for intra-data center application. Performance of the wavelength converter multicasting operation of two channels has also been assessed by controlling the distributed-feedback lasers. Experimental results show 4.5 dB power penalty after multicast wavelength conversion. The wavelength conversion of uni-/multi-casting operations would provide a compact, low power, and low-cost solution for wavelength routing-based intra-data center networking applications.

Wavelength conversion of 28 GBaud 16-QAM signals based on four-wave mixing in a silicon nanowire

We demonstrate error-free wavelength conversion of 28 GBaud 16-QAM single polarization (112 Gb/s) signals based on four-wave mixing in a dispersion engineered silicon nanowire (SNW). Wavelength conversion covering the entire C-band is achieved using a single pump. We characterize the performance of the wavelength converter subsystem through the electrical signal to noise ratio penalty as well as the bit error rate of the converted signal as a function of input signal power. Moreover, we evaluate the degradation of the optical signal to noise ratio due to wavelength conversion in the SNW.

Forward error correction supported 150 Gbit/s error-free wavelength conversion based on cross phase modulation in silicon

We build a forward error correction (FEC) module and implement it in an optical signal processing experiment. The experiment consists of two cascaded nonlinear optical signal processes, 160 Gbit/s all optical wavelength conversion based on the cross phase modulation (XPM) in a silicon nanowire and subsequent 160 Gbit/s-to-10 Gbit/s demultiplexing in a highly nonlinear fiber (HNLF). The XPM based all optical wavelength conversion in silicon is achieved by off-center filtering the red shifted sideband on the CW probe. We thoroughly demonstrate and verify that the FEC code operates correctly after the optical signal processing, yielding truly error-free 150 Gbit/s (excl. overhead) optically signal processed data after the two cascaded nonlinear processes.

Stabilized Wide-Band Wavelength Conversion Enabled by CW-Triggered Supercontinuum

We experimentally demonstrate a wide-band wavelength converter enabled by continuous-wave (CW) triggered supercontinuum (SC) generated from a picosecond pulse source. In the presence of the trigger, the pulse-to-pulse SC stability considerably improved, leading to error-free wavelength conversion operations spanning from 1510 to 1615 nm, which covers the S-, C-, and L-bands of the ITU grids. In addition, the CW-triggered SC spectrum is significantly enhanced to over 300 nm measured at 20 dB below the peak spectral power (from ~1400 to 1700 nm and beyond). Our scheme thus provides a low pump power and wide-band solution for fiber-based optical wavelength conversion. With its better CW source, e.g., lower relative intensity noise and longer coherence length, the present scheme has the potential to be further applied to phase-modulated signals.

Phase-Incoherent DQPSK Wavelength Conversion Using a Photonic Integrated Circuit

We investigate the performance of a large-scale, silica-on-silicon photonic integrated circuit for multiformat signal processing, and we experimentally demonstrate wavelength-conversion of (differential) quadrature phase-shift keying [(D)QPSK] signals. The circuit exploits phase-incoherent techniques to decode the input signal and to phase remodulate two phase-shift-keying components before combining them in a common QPSK output stream. Error-free wavelength conversion with 4-dB power penalty is reported at 44 Gb/s.

Flexible Broadband Wavelength Conversion in Quantum-Dot Semiconductor Optical Amplifiers

We successfully demonstrate error-free broadband wavelength conversion using cross-gain modulation in a quantum-dot semiconductor optical amplifier (QD-SOA). Because of the wide gain bandwidth of the QD-SOA, a wide gain range is available for the wavelengths of the original and converted signals. As a result, the operating wavelength of the converted signal is flexibly tuned in a 150-nm wavelength range covering the S/C/L-bands.

80 Gb/s wavelength conversion using a quantum-dot semiconductor optical amplifier and optical filtering

Wavelength conversion of 40 Gb/s and 80 Gb/s return-to-zero on-off-keying signals using a quantum-dot semiconductor optical amplifier in combination with a delay interferometer as subsequent filter is demonstrated. The performance of the 80 Gb/s wavelength converter measured in terms of the bit-error ratio demonstrated here is the highest reported up to now for quantum-dot semiconductor optical amplifiers. The typical fast gain dynamics manifests itself in open eye diagrams of the converted signal. The slow phase dynamics of the carrier reservoir however induces severe patterning and requires compensation. Adaptation of the free-spectral range of the delay interferometer is necessary in order to mitigate these phase effects and to achieve error-free wavelength conversion.

40 Gb/s wavelength conversion via four-wave mixing in a quantum-dot semiconductor optical amplifier

The static and dynamic characteristics of degenerate four-wave mixing in a quantum dot semiconductor optical amplifier are investigated. A high chip conversion efficiency of 1.5 dB at 0.3 nm detuning, a low (< 5 dB) asymmetry of up and down conversion and a spectral conversion range of 15 nm with an optical signal-to-noise ratio above 20 dB is observed. The comparison of pumping near the gain peak and at the edge of the gain spectrum reveals the optical signal-to-noise ratio as the crucial parameter for error-free wavelength conversion. Small-signal bandwidths well beyond 40 GHz and 40 Gb/s error-free 5 nm wavelength down conversion with penalties below 1 dB are presented. Due to the optical signal-to-noise ratio limitation, wavelength up conversion is error-free at a pump wavelength of 1311 nm with a penalty of 2.5 dB, whereas an error floor is observed for pumping at 1291 nm. A dual pump configuration is demonstrated, to extend the wavelength conversion range enabling 15.4 nm error-free wavelength up conversion with 3.5 dB penalty caused by the additional saturation of the second pump. This is the first time that 40 Gb/s error-free wavelength conversion via four-wave mixing in quantum-dot semiconductor optical amplifiers is presented.

160-Gb/s all-optical phase-transparent wavelength conversion through cascaded SFG-DFG in a broadband linear-chirped PPLN waveguide

We experimentally demonstrated ultra-fast phase-transparent wavelength conversion using cascaded sum- and difference-frequency generation (cSFG-DFG) in linear-chirped periodically poled lithium niobate (PPLN). Error-free wavelength conversion of a 160-Gb/s return-to-zero differential phase-shift keying (RZ-DPSK) signal was successfully achieved. Thanks to the enhanced conversion bandwidth in the PPLN with linear-chirped periods, no optical equalizer was required to compensate the spectrum distortion after conversion, unlike a previous demonstration of 160-Gb/s RZ on-off keying (OOK) using fixed-period PPLN.

High-Speed Wavelength Converter Capable of Converting the Same Wavelength Using a Single SOA in a Counterpropagation Scheme

We present a high-speed optical wavelength converter that is capable of converting the data to the same wavelength using a single semiconductor optical amplifier. Error-free wavelength conversion is demonstrated at a bit-rate of 40 Gb/s. The wavelength converter utilizes a counterpropagation scheme assisted by blue-detuned optical filtering technology. The blue-detuned optical filter shortens the recovery time of the wavelength converter, from initial 100 ps down to less than 6 ps, ensuring 40-Gb/s operation. The counterpropagation scheme shows a slow gain saturation time, which becomes a determinant factor for the operating speed of the proposed system. This wavelength converter is constructed by using commercially available fiber pigtailed components. It has a simple configuration and allows photonic integration.

Error-free wavelength conversion at 160 Gbit/s in PPLN waveguide at room temperature

Tunable wavelength conversion of a 160 Gbit/s signal by means of cascaded sum frequency generation/difference frequency generation was performed on a periodically-poled lithium niobate waveguide. Operation at room temperature (25degC) is demonstrated. A maximum power penalty of 2.1 dB for a bit error rate of 10 -9 was achieved over a wavelength range of 29 nm.

40 Gb/s Field-Modulated Wavelength Converters for All-Optical Packet Switching

We present a high-functionality photonic integrated circuit that performs field-modulated wavelength conversion. This device incorporates an on-chip sampled grating distributed Bragg reflector laser for wide tunability. Wavelength conversion is accomplished using a preamplified semiconductor optical amplifier photodiode receiver interconnected with a traveling-wave modulator to form a high-speed optical gate. This paper discusses the design and performance of this device, as well as its potential for optical packet switching applications. Error-free wavelength conversion is demonstrated at 40 Gb/s with 1-3 dB power penalty compared with back-to-back transmission over 22 nm of input and output tuning. Output extinction in all cases is greater than 9 dB, and conversion efficiency ranges from -2 to -6 dB over the tuning range. This device additionally demonstrates the capability for external 10 Gb/s modulation, which can be used for optical label encoding.

Error-free wavelength conversion via cross-phase modulation in 5 cm of As 2 S 3 chalcogenide glass rib waveguide

The first demonstration of all-optical signal processing at telecommunication data rates in chalcogenide glass waveguides is reported. Error-free wavelength conversion via cross-phase modulation in a low-loss, 5 cm-long As2S3 chalcogenide planar waveguide, over a 25 nm wavelength range at 10 Gbit/s, was achieved, yielding a Q-factor penalty of 2.3 dB.

Design and Operation of a Monolithically Integrated Two-Stage Tunable All-Optical Wavelength Converter

We report on the design and testing of a novel two-stage wavelength-converter architecture, monolithically fabricated in indium phosphide. Two widely tunable integrated sampled-grating distributed Bragg reflector lasers are utilized on chip as probes in both converter stages. The architecture provides a first-stage tunable signal that is internal to the chip (lambdainternal), facilitating cascaded integration of wavelength-sensitive structures, or allowing wavelength conversion for cases where the input wavelength is equal to the output wavelength (lambdainput = lambdaoutput). Output wavelength tuning over 35 nm is shown, and error-free wavelength conversion for lambdainput = lambdaoutput is demonstrated for four wavelengths over a 20-nm range at 2.5 Gb/s. Dynamic range measurements show less than 2 dB of power penalty over a 15-dB variation in input power.

Tunable All-Optical Wavelength Conversion of 160-Gb/s RZ Optical Signals by Cascaded SFG-DFG Generation in PPLN Waveguide

We report, for the first time, tunable all-optical wavelength conversion of 160-Gb/s return-to-zero (RZ) optical signals based on cascaded sum- and difference-frequency generation in a periodically poled LiNbO3 waveguide. The distorted signals due to limited phase-matching bandwidth during conversion were compensated by spectral reshaping. We achieved error-free tunable wavelength conversion with a bit-error rate of less than 10-9 for 160-Gb/s RZ signals in a 23-nm tuning range over the C-band

Bidirectional Data Injection Operation of Hybrid Integrated SOA–MZI All-Optical Wavelength Converter

A bidirectional data signal input scheme of a semiconductor optical amplifier--Mach-Zehnder interferometer (SOA-MZI) wavelength converter was proposed and experimentally verified for a nonreturn-to-zero (NRZ)-format signal. Theoretical analyses reveal that it is possible to mitigate the patterning effect induced by cross-gain modulation (XGM) by utilizing the difference of the ratio between the XGM and cross-phase modulation on the injection directions of data signals. A hybrid integrated SOA-MZI all-optical wavelength converter, in which the coupling loss between the SOA and the silica waveguide was as small as 1 dB owing to a unique active alignment technique, was used for the experiment. We have verified the superior characteristics of the proposed operation scheme for the first time. Error-free wavelength-conversion operation for an NRZ signal at 40 Gb/s was confirmed

Monolithic Wavelength Converters for High-Speed Packet-Switched Optical Networks

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper describes the design and demonstration of advanced 40-Gb/s return-to-zero (RZ) tunable all-optical wavelength converter technologies for use in packet-switched optical networks. The device designs are based on monolithic integration of a delayed interference Mach–Zehnder interferometer (MZI) semiconductor optical amplifier (SOA) wavelength converter with a sampled-grating distributed Bragg reflector tunable laser and an on-chip waveguide delay. Experimental results are presented demonstrating error-free wavelength conversion with 1-dB power penalty at 40-Gb/s data rates. By incorporating label modulation functionality on-chip along with a fast tunable 40-Gb/s wavelength converter, fully monolithic packet-forwarding chips are realized that are capable of simultaneous error-free wavelength conversion of 40-Gb/s payloads, remodulation of 10-Gb/s packet headers, and data routing through fast wavelength switching. </para>

Error-Free 320-Gb/s All-Optical Wavelength Conversion Using a Single Semiconductor Optical Amplifier

We demonstrate error-free wavelength conversion at 320 Gb/s by employing a semiconductor optical amplifier that fully recovers in 56 ps. Error-free operation is achieved without using forward error correction technology. We employ optical filtering to select the blue sideband of the spectrum of the probe light, to utilize fast chirp dynamics introduced by the amplifier, and to overcome the slow gain recovery. This leads to an effective recovery time of less than 1.8 ps for the wavelength converter. The wavelength converter has a simple configuration and is implemented by using fiber-pigtailed components. The concept allows photonic integration