Injection locked semiconductor lasers for realization of novel rf

University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2012 Injection-locked Semiconductor Lasers For Realization Of Novel Rf Photonics Components Nazanin Hoghooghi University of Central Florida Part of the Electromagnetics and Photonics Commons, and the Optics Commons Find similar works at: https://stars.edu/etd University of Central Florida Libraries http://library.edu This Doctoral Dissertation (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact STARS@ucf. STARS Citation Hoghooghi, Nazanin, "Injection-locked Semiconductor Lasers For Realization Of Novel Rf Photonics Components" (2012).

Electronic Theses and Dissertations, 2004-2019.edu/etd/2205 INJECTION-LOCKED SEMICONDUCTOR LASERS FOR REALIZATION OF NOVEL RF PHOTONICS COMPONENTS by NAZANIN HOGHOOGHI B. Iran University of Science and Technology, 2005 M. Rose-Hulman Institute of Technology, 2007 A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in CREOL, The College of Optics and Photonics at the University of Central Florida Orlando, Florida Summer Term 2012 Major Professor: Peter J. © 2012 Nazanin Hoghooghi ii ABSTRACT This dissertation details the work has been done on a novel resonant cavity linear interferometric modulator and a direct phase detector with channel filtering capability using injection-locked semiconductor lasers for applications in RF photonics.

First, examples of optical systems whose performance can be greatly enhanced by using a linear intensity modulator are presented and existing linearized modulator designs are reviewed. The novel linear interferometric optical intensity modulator based on an injection-locked laser as an arcsine phase modulator is introduced and followed by numerical simulations of the phase and amplitude response of an injection-locked semiconductor laser. The numerical model is then extended to study the effects of the injection ratio, nonlinear cavity response, depth of phase and amplitude modulation on the spur-free dynamic range of a semiconductor resonant cavity linear modulator. Experimental results of the performance of the linear modulator implemented with a multi-mode Fabry-Perot semiconductor laser as the resonant cavity are shown and compared with the theoretical model.

The modulator performance using a vertical cavity surface emitting laser as the resonant cavity is investigated as well. Very low Vπ in the order of 1 mV, multi-gigahertz bandwidth (-10 dB bandwidth of 5 GHz) and a spur-free dynamic range of 120 dB.Hz2/3 were measured directly after the modulator. The performance of the modulator in an analog link is experimentally investigated and the results show no degradation of the modulator linearity after a 1 km of SMF. The focus of the work then shifts to applications of an injection-locked semiconductor laser as a direct phase detector and channel filter.

This phase detection technique does not iii require a local oscillator. Experimental results showing the detection and channel filtering capability of an injection-locked semiconductor diode laser in a three channel system are shown. The detected electrical signal has a signal-to-noise ratio better than 60 dB/Hz. In chapter 4, the phase noise added by an injection-locked vertical cavity surface emitting laser is studied using a self-heterodyne technique.

The results show the dependency of the added phase noise on the injection ratio and detuning frequency. The final chapter outlines the future works on the linear interferometric intensity modulator including integration of the modulator on a semiconductor chip and the design of the modulator for input pulsed light. iv To my family v ACKNOWLEDGMENTS I would like to thank past and present members of Ultrafast Photonics group for all their continuous supports. They are Prof.

Peter Delfyett, Dr. Sarper Ozharar, Dr. Frank Quinlan, Dr. Ji-Myoung Kim, Dr.

Ibrahim Ozdur, Dr. Dimitrios Mandridis, Mohammad Umar Piracha, Charles Williams, Sharad Bhooplapur, Abhijeet Ardey, Dat Nguyen, Josue Davila-Rodriguez, Marcus Bagnell, Edris Sarailou, Anthony Klee, and Kristina Bagnell. I would particularly like to emphasize the importance of Prof. Peter Delfyett, Dr.

Ibrahim Ozdur and Josue Davila-Rodriguez without whom none of what follows would have been possible. vi TABLE OF CONTENTS LIST OF FIGURES .x LIST OF TABLES. xviii CHAPTER 1: INTRODUCTION .1 Injection locking of lasers .2 Applications of injection locked lasers. 4 CHAPTER 2: RESONANT CAVITY LINEAR INTERFEROMETRIC INTENSITY MODULATOR .2 Intensity modulation techniques .1 Direct modulation of light intensity .2 External modulation of light intensity .1 Predistortion linearization scheme .2 Feedforward linearization scheme .3 Linearized ring resonator assisted Mach-Zehnder modulators .4 Dual parallel Mach-Zehnder modulator.5 Cascaded Mach-Zehnder modulators .6 Directional coupler with two passive biases .4 Resonant cavity linear interferometric intensity modulator.1 Phase response of an injection locked semiconductor laser .2 Dynamic stability of an injection locked semiconductor laser .3 Linearity of modulator response .1 Resonant cavity linear modulator with a Fabry-Pérot laser as the resonant cavity .2 Resonant cavity linear modulator with a VCSEL as the resonant cavity .3 Measurements of the linear modulator SFDR .4 SFDR measurements of an analog optical link with the linear modulator .6 Discussions and conclusion.

78 CHAPTER 3: DIRECT DEMODULATION AND CHANNEL FILTERING OF PHASE MODULATED OPTICAL SIGNALS .4 Application in a cross connect switch. 93 CHAPTER 4: PHASE NOISE OF AN INJECTION LOCKED SEMICONDUCOTR LASER .1 Self-heterodyne setup. 100 CHAPTER 5: FUTURE WORKS.1 Monolithic integration of the linear modulator .2 Resonant cavity linear interferometric modulator for pulsed light .106 ix LIST OF FIGURES Figure 1. Injection locking of two lasers.

Behavior of the slave laser when the injection seed is tuned inside or outside the locking range [3]. Analog link in a remote antenna system. Block diagram of a SCM-WDM system. Block diagram of a conventional OEO.

A typical electro-optic intensity modulator. A Pockel cell is placed between two crossed polarizers. Output modulated light intensity versus the modulating voltage of an electro-optic modulator. An integrated Mach-Zehnder optical intensity modulator.

Calculation of SFDR from the fundamental and third-order intermodulation power vs. input RF power plot. Plot of maximum achievable SNR as a function of average photocurrent. Thermal noise and shot noise limits are shown in blue and red lines, respectively.

The green line is the maximum achievable SNR for a system with -155 dBc/Hz RIN. Predistortion linearizer system[35]. Block diagram of a feedforward linearization system. Schematic of a dual RRMZM optical intensity modulator in push–pull configuration [31].

A hybrid RRMZM modulator. γ is the coupling coefficient of the ring resonator. The phase modulator and the ring resonator are driven by the same RF signal with a power split ratio of F and 1-F[30]. Schematic of a dual parallel Mach-Zehnder modulator [32].

Schematic of a cascaded Mach-Zehnder modulator[33]. Schematic of a directional coupler with two passive biases [43]. Resonant cavity linear interferometric intensity modulator setup. Simulation results: (a) SFDR vs.

depth of modulation (b) SFDR vs. bias point of the modulator at 10% depth of modulation. Normalized output power of an injection-locked semiconductor laser as a function of frequency detuning (α =1).Graphical representation of the resonant cavity frequency shift and its relative phase to the master laser at different detuning frequencies across the locking range. Normalized output power of an injection-locked semiconductor laser as a function of frequency detuning (α =0).

Phasor diagram of the master and slave laser electric fields within the locking range for α=0. Normalized output power of an injection locked laser for α= 0, 1, 2, and 3. frequency detuning for different injection ratios and for (a) α =0 and (b) α =3. The unlocked regions are shown by dashed lines in (b).

Stability plot of an injection locked semiconductor laser with parameters listed in Table 1. Surface plot of signal-to-intermodulation ratio as a function of depth of modulation and injection ratio for α =3. (a) Signal-to-intermodulation ratio vs. injection ratio at 40% depth of modulation, (b) Signal-to-intermodulation vs.

depth of phase modulation at 0. Signal-to-intermodulation ratio vs. injection ratio for a nonlinear (red) and linear (blue) cavity responses. Experimental setup for measuring the signal-to-intermodulation ratio of the modulator.

BS: Beam splitter; WP: Waveplate; FPL: Fabry–Pérot laser; RFSA: Radio frequency spectrum analyzer; OSA: Optical spectrum analyzer. Optical spectra of the Fabry-Pérot laser (a) not injection locked (b) injection locked. (a)-(d)Evolution of the undamped relaxation oscillation frequencies within the locking range. Detected RF power spectra (a) fundamental frequencies (b) one of the third- order intermodulation frequencies (200 MHz).

Theoretically calculated and measured values of signal-to-intermodulation ratio at different input RF drive powers with 0. Structure of a VCSEL device. Characteristics of the VCSEL device used in the experiment (a) L-I curve (b) frequency tunablity curve. System diagram: VCSEL: Vertical cavity surface emitting laser, VOA: Variable optical attenuator, PZT: Piezo electric transducer, PC: Polarization controller, Iso: Isolator, CIR: Circulator, PD: Photodetector, RFSA: Radio frequency spectrum analyzer, High-res OSA: High resolution optical spectrum analyzer.Static phase shift plot of the injection-locked VCSEL.

(a) Detected intensity modulated signal at the output of the resonant cavity modulator at 20 MHz modulation frequency and (b) frequency response of the linear modulator. The -10 dB bandwidth is ~5 GHz. SFDR measurements: (a) Power spectrum at the output of the two-tone SFDR measurement using 300 and 400 MHz tones (b) Low resolution bandwidth (1 Hz) spectrum of the 500 MHz third order intermodulation tone. Frequency stability measurement setup.

Free running VCSEL beating with a stable source (Orbits lightwave). Injection-locked VCSEL beating with a stable source (Orbits lightwave). System diagram of the linear modulator with a simple bias point locking scheme. Iso: Isolator; VOA: Variable optical attenuator; PC: Polarization controller; VCSEL: Vertical cavity surface emitting laser; PZT: piezoelectric transducer (fiber stretcher); EDFA: Erbium-doped fiber amplifier; PD: Photodetector; OSA: Optical spectrum analyzer, PID: proportional-integral-differential controller; RFA: Radio frequency amplifier; RFSA: Radio frequency spectrum analyzer.

Error signal before and after locking the bias point of the modulator taken over 10 second. Sample photodetected RF spectrum of the modulator at -36 dBm input RF power. Fundamental and third-order intermodulation power vs. input RF power to the modulator.

Measured RIN of the injection seed laser, free running VCSEL and injection locked VCSEL at 5. Measured SFDR directly after the modulator vs. bias point of the modulator. System diagram of an analog optical link with a linear modulator.

Iso: Isolator; VOA: Variable optical attenuator; PC: Polarization controller; VCSEL: Vertical cavity surface emitting laser; PZT: piezoelectric transducer (fiber stretcher); EDFA: Erbium-doped fiber amplifier; PD: Photodetector; High-res OSA: High resolution optical spectrum analyzer, PID: proportional-integral-differential controller; RFA: Radio frequency amplifier; RFSA: Radio frequency spectrum analyzer. Sample photodetected RF spectrum at the receiver side. Fundamental and third-order intermodulation power vs. input RF power to the modulator.

The analog link SFDR is calculated to be 120 dB. (a) Phase and amplitude response within the locking range, (b)Change of the voltage across the active region of the injection locked semiconductor laser by changing the master laser frequency in time. Change of the voltage across the active region of injection locked VCSEL (a) schematic of setup (b) Measured voltage vs. Schematic of a single channel system with injection locked VCSEL as the receiver.

ISO: isolator, PC: polarization controller, PM: phase modulator, VOA: variable optical attenuator, CIR: circulator, OSA: optical spectrum analyzer, RF Amp.: radio frequency amplifier, RFSA: radio frequency spectrum analyzer. Measured optical and RF power spectra. (a)-(b) the phase modulated signal is injected to the VCSEL but outside the locking range.(c)-(d) the VCSEL is locked to the phase modulated signal. Real-time oscilloscope traces of the detected phase modulated signal (solid line) and the drive signal of the phase modulator (dash line).

Note that the drive signal is scaled down for better comparison. Schematic of a three-channel back-to-back link with the injection locked VCSEL as a wavelength selective element and phase detector. IM: Intensity modulator, PM: Phase modulator, CIR: Circulator, VCSEL: Vertical cavity surface emitting laser, OSA: Optical spectrum analyzer, RFSA: Radio frequency spectrum analyzer. Optical spectrum of the VCSEL and the phase modulated signals injected to its cavity.

The VCSEL is not locked to any of the channels. Note the phase modulation side bands of the received optical carriers.9 GHz and 1 GHz are the phase modulation frequencies of channels 1 to 3, respectively.