Designer Oriented Analysis Of An All-Optical Binary Delta Sigma Modulator

Photonic analog-to-digital converters.

Abstract: This paper reviews over 30 years of work on photonic analog-to-digital converters. The review is limited to systems in which the input is a radio-frequency (RF) signal in the electronic domain and the output is a digital version of that signal also in the electronic domain, and thus the review excludes photonic systems directed towards digitizing images or optical communication signals. The state of the art in electronic ADCs, basic properties of ADCs and properties of analog optical links, which are found in many photonic ADCs, are reviewed as background information for understanding photonic ADCs. Then four classes of photonic ADCs are reviewed: 1) photonic assisted ADC in which a photonic device is added to an electronic ADC to improve performance, 2) photonic sampling and electronic quantizing ADC, 3) electronic sampling and photonic quantizing ADC, and 4) photonic sampling and quantizing ADC. It is noted, however, that all 4 classes of "photonic ADC" require some electronic sampling and quantization. After reviewing all known photonic ADCs in the four classes, the review concludes with a discussion of the potential for photonic ADCs in the future.

Injection locking properties of a semiconductor laser

Abstract: Injection locking properties of a semiconductor laser have been analyzed, taking into account the injected carrier density dependent refractive index in the active region. It has been found that this dependence significantly affects the injection locking properties, giving rise to a peculiar asymmetric tuning curve and dynamic instability. The instability originates from the intermode interaction via the modulation in the injected carrier density caused by intensity beat. The detuning dependence of the direct modulation response characteristics inside and outside of the locking range have also been examined.

All-optical flip-flop based on coupled laser diodes

Abstract: An all-optical set-reset flip-flop is presented that is based on two coupled lasers with separate cavities and lasing at different wavelengths. The lasers are coupled so that lasing in one of the lasers quenches lasing in the other laser. The flip-flop state is determined by the laser that is currently lasing. A rate-equation based model for the flip-flop is developed and used to obtain steady-state characteristics. Important properties of the system, such as the minimum coupling between lasers and the optical power required for switching, are derived from the model. These properties are primarily dependent on the laser mirror reflectivity, the inter-laser coupling, and the power emitted from one of the component lasers, affording the designer great control over the flip-flop properties. The flip-flop is experimentally demonstrated with two lasers constructed from identical semiconductor optical amplifiers (SOAs) and fiber Bragg gratings of different wavelengths. Good agreement between the theory and experiment is obtained. Furthermore, switching over a wide range of input wavelengths is shown; however, increased switching power is required for wavelengths far from the SOA gain peak.

All‐optical flip‐flop based on coupled laser diodes

Abstract: An all-optical set-reset flip-flop is presented that is based on two coupled identical laser diodes. The lasers are coupled so that when one of the lasers lases, it quenches lasing in the other laser. The state of the flip-flop is determined by which laser is currently lasing. Rate equations are used to model the flip-flop, and it is experimentally demonstrated by the use of antireflection-coated laser diodes and free-space optics. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 157-159, 2000.

Photonic analog-to-digital conversion

Abstract: 1. Introduction.- 1.1 The Role of A/D Conversion.- 1.2 Key Technological Challenges.- 1.3 Motivation for Photonic A/D Approaches.- 1.4 Organization of this Book.- 2. Performance Characteristics of Analog-to-Digital Converters.- 2.1 A/D Converter Characteristics.- 2.2 Sampling and Conversion Rate Characteristics.- 2.2.1 Sampling Rate.- 2.2.2 Conversion Rate.- 2.3 Performance Measures.- 2.3.1 Resolution.- 2.3.2 Dynamic Range, SQNR, and SNR Performance Measures..- 2.3.3 Spur-Free Dynamic Range.- 2.4 Performance Degradations.- 2.4.1 Two-Tone Intermodulation Distortion.- 2.4.2 Differential Nonlinearity.- 2.4.3 Integral Nonlinearity.- 2.4.4 Comparator Hysteresis.- 2.4.5 Thermal Noise.- 2.16 Aperture Jitter.- 2.4.7 Comparator Ambiguity.- 2.4.8 Observations.- Summary.- 3. Approaches to Analog-to-Digital Conversion.- 3.1 A/D Converter Coding Schemes.- 3.1.1 Thermometer Coding Scheme.- 3.1.2 Gray Code Coding Scheme.- 3.1.3 Circular Coding Scheme.- 3.2 Nyquist-Rate Converter Architectures.- 3.2.1 Fully Parallel or Flash A/D Conversion.- 3.2.2 Subranging A/D Conversion.- 3.2.3 Folding Architectures.- 3.2.4 Other Parallel Architectures.- 3.2.5 Neural Network Approach to A/D Conversion..- 3.2.6 Full-Search A/D Conversion.- 3.2.7 Successive Approximation A/D Conversion.- 3.3 Oversampled A/D Conversion.- 3.3.1 The Modulator.- 3.3.2 Operation.- 3.3.3 The Digital Postprocessor.- 3.3.4 Oversampled A/D Performance.- 3.4 Parallel Oversampling A/D Conversion.- Summary.- 4. Photonic Devices for Analog-to-Digital Conversion.- 4.1 Mach-Zehnder Interferometers.- 4.2 Optical Waveguide Switches.- 4.2.1 Directional Coupler Waveguide Switches.- 4.2.2 Reversed ?? Directional Coupler..- 4.2.3 Digital Optical Waveguide Switches.- 4.3 Acousto-Optic Devices.- 4.4 Multiple Quantum Well Devices.- 4.4.1 Optical Bistability.- 4.4.2 Optical Subtraction.- 4.4.3 Switching Speed and Energy Requirements.- 4.5 Smart Pixel Technology.- 4.5.1 Monolithic Integration.- 4.5.2 Direct Epitaxy.- 4.5.3 Hybrid Integration.- Summary.- 5. Nyquist-Rate Photonic Analog-to-Digital Conversion.- 5.1 Electro-Optic A/D Conversion Based on a Mach-Zehnder Interferometer.- 5.2 Optical Folding-Flash A/D Converter.- 5.3 Matrix-Multiplication and Beam Deflection.- 5.4 Other Approaches to Photonic A/D Conversion.- Summary.- 6. Oversampled Photonic Analog-to-Digital Conversion.- 6.1 Oversampling Photonic A/D Conversion.- 6.2 Optical Oversampled Modulators.- 6.2.1 The Interferometric Modulator.- 6.2.2 The Noninterferometric Modulator.- 6.3 The Digital Postprocessor.- 6.3.1 Electronic Postprocessing.- 6.3.2 Optoelectronic Postprocessing.- 6.3.3 Observations.- 6.4 Performance Analysis.- 6.4.1 Linear Arithmetic Errors.- 6.4.2 Quantization Noise Spectra.- 6.4.3 Cascade Error Tolerances..- 6.5 Experimental Proof-of-Concept Photonic Modulator Demonstration.- 6.5.1 Noninterferometric Optical Subtraction.- 6.5.2 Experimental Photonic First-Order Oversampled Modulator.- Summary.- 7. Low Resolution, Two-Dimensional Analog-to-Digital Conversion: Digital Image Halftoning.- 7.1 Introduction.- 7.2 Approaches to Halftoning.- 7.3 The Error Diffusion Algorithm.- 7.4 Neural Network Formalism.- 7.4.1 The Hopfield-Type Neural Network.- 7.4.2 Observations.- 7.5 The Error Diffusion Neural Network.- 7.5.1 The Error Diffusion Filter.- 7.5.2 Observations.- 7.6 Quantitative Performance Metrics.- 7.6.1 Power Spectrum Estimation.- 7.6.2 Radially Averaged Power Spectra and Anisotropy.- 7.7 Performance Analysis.- 7.7.1 Floyd-Steinberg Performance Analysis.- 7.7.2 Symmetric Jarvis Performance Analysis.- 7.7.3 Error Diffusion Neural Network Performance Analysis.- 7.8 Extensions to Color.- Summary.- 8. A Photonic-Based Error Diffusion Neural Network.- 8.1 First-Generation CMOS-SEED Error Diffusion Neural Array.- 8.2 Second-Generation CMOS-SEED Error Diffusion Neural Array.- 8.2.1 Detailed Circuit Description.- 8.2.2 Modeling and Simulation.- 8.2.3 Experimental Performance..- 8.2.4 Observations.- 8.3 OPTOCHIP: A 2-D Neural Array Employing Epitaxy-on-Electronics.- 8.3.1 The OPTOCHIP Project.- 8.3.2 Description of Device Architecture.- 8.3.3 Observations.- 8.4 Extensions: A Photonic Error Diffusion Filter.- 8.4.1 Design of the Diffractive Optical Filter.- 8.4.2 Fabrication Error Analysis..- 8.4.3 Experimental Characterization.- 8.4.4 Impact of Fabrication Errors on Halftoning Performance.- Summary.- 9. Photonic A/D Conversion Based on a Fully Connected Distributed Mesh Feedback Architecture.- 9.1 Temporal and Spatial Error Diffusion.- 9.1.1 Spectral Noise Shaping Duality.- 9.1.2 Postprocessing Duality.- 9.1.3 Limit Cycle Oscillation Duality.- 9.1.4 Observations.- 9.2 Spatially Distributed Oversampled A/D Conversion..- 9.3 A 2-D Fully Connected Distributed Mesh Feedback Architecture.- 9.3.1 Mismatch Effects in the Fully Connected Distributed Mesh Feedback Architecture.- 9.4 A/D Conversion Using Spatial Oversampling and Error Diffusion.- 9.4.1 Temporal-to-Spatial Conversion.- 9.4.2 The Two-Dimensional Error Diffusion Neural Network.- 9.4.3 The Postprocessor.- 9.4.4 Spectral Noise Shaping.- 9.4.5 Observations.- 9.5 Three-Dimensional Extensions.- 9.5.1 Space-Time Processing Architectures.- Summary.- 10. Trends in Photonic Analog-to-Digital Conversion.- 10.1 Time-Interleaving A/D Converter Architectures.- 10.1.1 Understanding Time-Interleaved Architectures.- 10.1.2 Mismatch Effects in Time-Interleaved Architectures.- 10.1.3 Block Filter Description of Time-Interleaving.- 10.2 Photonic Channelized A/D Architectures.- 10.2.1 Optical Time-Division Demultiplexing Architectures.- 10.2.2 Wavelength Channelization Architectures.- 10.3 Time-Stretching Using Dispersive Optical Elements.- 10.4 Ultra-Fast Laser Sources with Low Jitter.- 10.5 Novel Optical Sampling Techniques.- 10.6 Broadband Optical Modulators and Switches.- Summary.- References.