Single Single Semiconductor Optical Amplifier Research Articles

All-optical reconfigurable non-inverted logic gates with a single semiconductor optical amplifier

All-optical reconfigurable non-inverted logic gates with a single semiconductor optical amplifier (SOA) is proposed. Compared with the probe light of continuous light, the clock (Clk) pulse sequences light is regarded as the probe light so that the output of logic gates is a non-inverted code which is suitable to the further combination of different logic gates. The scheme is based on a single SOA with four-wave mixing and cross-gain modulation. Multiple functional logic operations are implemented and switched by adjusting the center wavelength of tunable optical band-pass filter without altering the experimental device. In the experiment, all-optical multiple logic gates with 10 Gb/s return-to-zero of NOT, NOR, XNOR, AND, A¯•B and A•B¯ are realized. Meanwhile, because Clk probe light is a small signal, a saturable absorber (SA) is configured to improve the extinction ratio (ER) and optical signal to noise ratio (OSNR). For logic gates NOT, NOR and XNOR with Clk probe light, ER and OSNR are only deteriorated by 1 dB with the SA. For logic gate AND with Clk probe light, ER is improved by about 2 dB based on four-wave mixing and OSNR keep the original values with the SA respectively. For logic gates A¯•B and A•B¯ without Clk probe light, ER and OSNR are both only deteriorated by 0.5 dB. It has the potential to obtain more complex combinational logic gates.

Single SOA based all-optical UWB doublet signal source

We propose a novel scheme to generate ultra-wideband (UWB) doublet pulses based on the cross-gain modulation (XGM) in a single semiconductor optical amplifier (SOA). The scheme is simple and compact since only a single SOA is used. The generated doublet signal containing only one wavelength can be easily controlled, and can avoid the dispersion effect. By using the software of Optisystem 7.0, the proposed UWB doublet signal is realized, and the effects of the current of SOA, the optical power and the wavelength of the optical source on the generated doublet pulse are numerically simulated and studied.

Single SOA based ultrafast all-optical wavelength conversion for PolSK signal

A novel ultrafast tunable all-optical wavelength conversion for polarization-shift-keying (PolSK) signal based on dual-pump four-wave mixing (FWM), including parallel dual-pump FWM and orthogonal dual-pump FWM, in a single semiconductor optical amplifier (SOA) is proposed. A comprehensive broad-band dynamic model of the all-optical wavelength converter based on parallel dual-pump FWM and orthogonal dual-pump FWM in SOA is developed, for the first time to our knowledge. By numerical simulation, the proposed all-optical wavelength conversion is realized at 40 Gbit/s. The effects of the powers of input waves and wavelength detuning on the conversion efficiency of the wavelength converter are theoretically investigated in detail. The results indicate that, due to using the PolSK modulation format, this scheme is free of pattern effect. In addition, a wide tuning range can be obtained. The proposed all-optical wavelength conversion for PolSK signal is robust and potential for applications in future optical networks in terms of simple implementation and high speed operation.

Single SOA based simultaneous amplitude regeneration for WDM-PDM RZ-PSK signals

We propose and demonstrate all-optical amplitude regeneration for the wavelength division multiplexing and polarization division multiplexing (WDM-PDM) return-to-zero phase shift keying (RZ-PSK) signals using a single semiconductor optical amplifier (SOA) and subsequent filtering. The regeneration is based on the cross phase modulation (XPM) effect in the saturated SOA and the subsequent narrow filtering. The spectrum of the distorted signal can be broadened due to the phase modulation induced by the synchronous optical clock signal. A narrow band pass filter is utilized to extract part of the broadened spectrum and remove the amplitude noise, while preserving the phase information. The working principle for multi-channel and polarization orthogonality preserving is analyzed. 4-channel dual polarization signals can be simultaneously amplitude regenerated without introducing wavelength and polarization demultiplexing. An average power penalty improvement of 1.75dB can be achieved for the WDM-PDM signals.

Parallel Eight Channels All-Optical NRZ-to-RZ Format Conversions at 40 Gb/s Using a Single SOA

We experimentally demonstrate simultaneous nonreturn-to-zero to return-to-zero (RZ) conversion for eight channels at 40 Gb/s with a single semiconductor optical amplifier (SOA) and a subsequent delay interferometer (DI), which is designed to have a specific free spectral range to accommodate the multiple dense wavelength-division-multiplexing channel spacing. The proposed conversions are based on the cross-phase modulation effect in a single SOA, which is operated in deep saturation to mitigate the undesired cross-gain modulation. Good quality RZ signals can be achieved by optimizing the detuning between the peaks in the DI spectrum and each corresponding carrier. The bit-error ratio results show that the conversions can be achieved with negative power penalty.

A novel wavelength conversion scheme based on a single SOA inserted MZI for all-optical switching network

A novel scheme of wavelength conversion based on single semiconductor optical amplifier (SOA) inserted Mach---Zehnder-interferometers (MZI) is proposed to resolve the optical packet contending in the paper. A signal phase adjuster is designed for MZI lower arms to change the optical signal phase difference between MZI upper arms and lower arms accurately. The SOA and input optical signal parameters are discussed and analyzed to optimize the scheme wavelength conversion performance for all-optical switching networks. Numerical analysis and simulation show that more than 20 dB contrast ratio can be achieved for the wavelength conversion at 40 Gbps. In addition, the system is simple structure, stable and photonic integratable.

Single and Multicasting Inverted-Wavelength Conversion at 80 Gb/s Based on a Single Semiconductor Optical Amplifier

We experimentally demonstrate single and multicasting inverted wavelength conversion at 80 Gb/s by using the cross-gain modulation and cross-phase modulation in a single semiconductor optical amplifier (SOA). In all the cases, converted signals with a high extinction ratio (ER) and large eye opening are obtained. For single-channel wavelength conversion, the ER of the output signal is as high as 30.10 dB. For three-channel wavelength multicasting, high quality converted signals could also be observed. The ERs with three channels are 21.54 dB, 18.58 dB and 17.72 dB, respectively. Thus, one- and three-channel wavelength conversion with high performance can be achieved by using a single quantum-well SOA.

Wide tuning range wavelength-swept laser with a single SOA at 1020 nm for ultrahigh resolution Fourier-domain optical coherence tomography

In this study, we demonstrated a wide tuning range wavelength-swept laser with a single semiconductor optical amplifier (SOA) at 1020 nm for ultrahigh resolution, Fourier-domain optical coherence tomography (UHR, FD-OCT). The wavelength-swept laser was constructed with an external line-cavity based on a Littman configuration. An optical wavelength selection filter consisted of a grating, a telescope, and a polygon scanner. Before constructing the optical wavelength selection filter, we observed that the optical power, the spectrum bandwidth, and the center wavelength of the SOA were affected by the temperature of the thermoelectric (TE) cooler in the SOA mount as well as the applied current. Therefore, to obtain a wide wavelength tuning range, we adjusted the temperature of the TE cooler in the SOA mount. When the temperature in the TE cooler was 9 °C, our swept source had a tuning range of 142 nm and a full-width at half-maximum (FWHM) of 121.5 nm at 18 kHz. The measured instantaneous spectral bandwidth (δλ) is 0.085 nm, which was measured by an optical spectrum analyzer with a resolution bandwidth of 0.06 nm. This value corresponds to an imaging depth of 3.1 mm in air. Additionally, the averaged optical power of our swept source was 8.2 mW. In UHR, FD/SS-OCT using our swept laser, the measured axial resolution was 4.0 μm in air corresponding to 2.9 μm in tissue (n = 1.35). The sensitivity was measured to be 93.1 dB at a depth of 100 μm. Finally, we obtained retinal images (macular and optic disk) and a corneal image.

All-optical parallel NRZ-DPSK to RZ-DPSK format conversion at 40 Gb/s based on XPM effect in a single SOA

We propose and demonstrate multi-channel parallel format conversions from the non return-to-zero differential phase shift keying (NRZ-DPSK) to the return-to-zero DPSK (RZ-DPSK) using a single semiconductor optical amplifier (SOA). The simultaneous conversions are based on the cross phase modulation (XPM) effect, which is induced by a synchronous optical clock signal with high input power. The XPM adds an identical phase shift onto every input bit, resulting in the phase difference unchanged. The input spectra are broadened and a subsequent filter is utilized to extract the specific part to form a RZ pulse. 6-channel NRZ-DPSK signals at 40 Gb/s can be converted to the corresponding RZ-DPSK signals with ~-0.8 to -1 dB power penalty for all the channels.

基于单个半导体光放大器的非线性偏振旋转效应实现全光可重构多逻辑门

We demonstrate an all-optical reconfigurable logic gate based on dominant nonlinear polarization rotation accompanied with cross-gain modulation effect in a single semiconductor optical amplifier (SOA). Five logic functions, including NOT, OR, NOR, AND, and NAND, are realized using 10-Gb/s on-off keying signals with flexible wavelength tunability. The operation principle is explained in detail. By adjusting polarization controllers, multiple logic functions corresponding to different input polarization states are separately achieved using a single SOA with high flexibility.

Regenerative multiwavelength conversion at 4 × 10‐GBit/S using a single SOA

AbstractWe experimentally demonstrate a regenerative multiwavelength conversion (MWC) of an input 10‐Gbit/s RZ signal to four output copies by using a single semiconductor optical amplifier (SOA) and a tunable band pass filter (TBPF). Experiment results indicate that improvements in detected Q factor can be observed because of the compression of the input noise. Furthermore, as the probe light we used is a multiwavelength pulses‐train with the same frequency as the data signal, this configuration can realize 3R regenerative MWC without any change. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 466–469, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24095

All optical format conversion at 10 Gbps using SOA and optical band-pass filter

In this paper, an all-optical non return-to-zero (NRZ) and return-to-zero (RZ) modulation format converter using a single semiconductor optical amplifier (SOA) and an optical band-pass filter (OBPF) is proposed. The format converter consists of a single SOA which is acting as a nonlinear element to broaden the spectrum of the input signal and the OBPF which is used to extract the special spectrum from the broadened spectrum. By adopting the ultra-fast SOA model associated with optical system software, the 10 Gbps NRZ and RZ format conversion is successfully demonstrated with simulation. We also demonstrate the proof-of-principle experiment at 10 Gbps by using the test SOA and OBF converter. The converted NRZ is achieved with an output extinction ratio of 11.51 dB. The BER is 5.5 × 10−9 while the power of NRZ is −10 dBm and the BER is 1.0 × 10−9 when the power of RZ is −14 dBm. The experimental results coincide well with the simulated results. The proposed scheme is robust and has potential for applications in future optical networks.

All-Optical RZ to NRZ Format Conversion Using Single SOA Assisted by Optical Band-Pass Filter

We propose a novel all-optical format conversion from the return-to-zero (RZ) to the non-return-to-zero (NRZ) based on single semiconductor optical amplifier (SOA) and optical band-pass filter (OBF). We demonstrate the proof of the principle experiment at 10Gbps by using the test SOA and OBF converter. The format conversion can be achieved with output extinction ratio of 11.51 dB. The BER is 5.5 × 10−9 when the power of NRZ is −10 dBm. The proposed scheme is robust and potential for applications in optical networks.

Single-SOA-Based Ultrahigh-Speed All-Optical Half Subtracter with PolSK Modulated Signals

A novel ultrahigh-speed all-optical half subtracter based on four-wave mixing (FWM) in a single semiconductor optical amplifier (SOA) is proposed. This scheme only requires a single SOA and two input signals without additional light source, so it is quite simple and compact. Due to the polarization-shift-keying (PolSK) modulated signals being used in this scheme, pattern-dependent degradation can be avoided. By numerical simulation, dependence of the critical factors of the logic gate performance, e.g., the output power of logic 1 and extinction ratio (ER), on two input signals power is investigated. In addition, the effect of the gain polarization dependence of SOA is analysed.

Optical UWB doublet pulse generation using multiple nonlinearities of single SOA

All-optical ultra-wideband (UWB) doublet pulse generation based on the multiple nonlinear effects of a single semiconductor optical amplifier (SOA) is demonstrated. First, a monocycle pulse is obtained by means of cross-gain modulation and self gain-saturation in the SOA, and a Gaussian pulse at conjugated light is obtained using four-wave mixing of the SOA. Secondly, the Gaussian pulse at the conjugated light is combined with the monocycle pulse by proper time delay to form a doublet pulse. The central frequency and 10 dB bandwidth of the doublet radio frequency are 5 and 6.25 GHz, respectively. The scheme is simple since only a single SOA is required.

40 Gbit/s reconfigurable photonic logic gates based on various nonlinearities in single SOA

40 Gbit/s reconfigurable photonic logic gates with XNOR, AND, NOR, OR and NOT functions are demonstrated, based on various nonlinearities of a single semiconductor optical amplifier (SOA), including four-wave mixing (FWM), cross-gain modulation (XGM) and transient cross-phase modulation (T-XPM). Detuning optical bandpass filters are employed to enhance the SOA modulation bandwidth.

40 Gb/s all-optical NRZ to RZ format conversion using single SOA assisted by optical bandpass filter

We propose a novel all-optical format conversion from nonreturn-to-zero (NRZ) to return-to-zero (RZ) based on single semiconductor optical amplifier (SOA) and a detuning optical bandpass filter (OBF). By adopting the ultrafast SOA model associated with intraband mechanism, the 40Gb/s NRZ-to-RZ format conversion is successfully demonstrated with numerical simulation. We investigate the influence of the filter detuning, extinction ratio, conversion efficiency, output pulsewidth, and filter bandwidth. These simulation results confirm the feasibility of our scheme. The proposed scheme is robust and potential for applications in future optical networks.

Single SOA based all-optical adder assisted by optical bandpass filter: Theoretical analysis and performance optimization

A simple and compact configuration of all-optical adders implemented with a single semiconductor optical amplifier (SOA) and optical bandpass filter (OBF) is presented in this paper. A comprehensive SOA model is put forward to investigate the output characteristics of the all-optical adders. The numerical simulation results demonstrate the influence of these key parameters, including input pulse peak power, pulsewidth, repetition rate, and OBF characteristics. Moreover some design rules are extracted for the proper selection of these parameters so as to ensure optimum performance. The obtained results confirm the feasibility of our configuration.