A frequency tunable optoelectronic oscillator based on a directly modulated distributed-feedback (DFB) semiconductor laser under optical injection is proposed and experimentally demonstrated. Through injection, the relaxation oscillation of DFB enhanced its high modulation efficiency can enable loop with RF threshold gain less than 20 dB. The commercial package 10 GHz, packaging limitation be overcome by injection. In our scheme, neither high-speed external modulator nor an electrical...

A novel scheme to realize a low-cost and wideband frequency tunable optoelectronic oscillator based on directly modulated distributed feedback (DFB) semiconductor laser is proposed experimentally demonstrated. In the scheme, neither an external modulator nor electrical filter used, no more than 25 dB of loop gain required due high modulation efficiency relaxation oscillation DFB laser. Microwave signals with coarsely tuned from 3.77 8.75 GHz are generated by changing bias current operation...

Photonic generation of linearly chirped microwave waveforms (LCMWs) using a monolithic integrated three-section laser is experimentally demonstrated in this work. All three sections the cavity, including front DFB section, phase section and rear have same active layer, which can avoid butt-joint re-growth process. The gratings both are fabricated by Reconstruction Equivalent Chirp technique, significantly decrease difficulties realizing precise grating structure. By adjusting semiconductor...

A novel approach to realizing an optoelectronic oscillator (OEO) based on integrated multi-section (IMS) distributed feedback (DFB) laser is proposed and experimentally demonstrated. Our scheme adopts the method of direct modulation a built-in microwave photonic filter (MPF), making structure simpler more flexible than external modulator electrical bandpass (EBPF). The IMS-DFB laser, which can overcome drawbacks using discrete lasers, key device in scheme. Further, two DFB sections, are...

A photonic microwave downconverter with improved conversion efficiency and spurious-free dynamic range (SFDR) is proposed experimentally demonstrated based on a dual-parallel Mach-Zehnder modulator (DPMZM) digital signal post-processing algorithm. The radio frequency (RF) the local oscillator (LO) are fed to two sub-MZMs of DPMZM, respectively, leading an infinite isolation between RF LO ports. By biasing parent MZM DPMZM at minimum transmission point, optical carrier can be greatly...

A novel approach to generating microwave frequency shift keying (FSK) signals using a polarization modulator (PolM) and dual-polarization Mach-Zehnder (DPol-MZM) is proposed experimentally demonstrated. In the system, PolM employed modulate state of an input linearly polarized lightwave switch between two orthogonal directions, leading generation (PolSK) signal. Then PolSK signal sent DPol-MZM, which made up multiplexed sub-MZMs by controller (PC). Two with different frequencies are applied...

In this Letter, the optical stealth transmission carried by super-continuum spectrum pulses generated in highly nonlinear fiber is proposed and experimentally demonstrated. scheme, signals are reshaped spectral domain through a wavelength-selective switch temporally spread chromatic dispersion device to achieve same noise-like characteristic as noise networks, so that both time domain, hidden public channel. Our experimental results show compared with existing schemes where channels...

A novel scheme for the generation of full-duty-cycle triangular pulses based on an optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The fundamental tone corresponding to repetition rate generated by OEO. Biasing Mach-Zehnder modulator at quadratic point, small-signal gain OEO maximized, while even-order harmonics in optical intensity are suppressed. By properly setting loop, amplitude first-order harmonic nine times that third-order harmonic. After a 90°...

The physical-layer security of a quantum-noise randomized cipher (QNRC) system is, for the first time, quantitatively evaluated with secrecy capacity employed as performance metric. Considering quantum noise channel advantage legitimate parties over eavesdroppers, specific wire-tap models both channels key and data are built outputs yielded by heterodyne measurement; general expressions capacities derived, where matching codes proved to be uniformly distributed. maximal achievable rate is...

A novel approach to realizing single sideband (SSB) modulation with optical carrier ratio (OCSR) of 0 dB, which is optimum for maximizing the transmission performance a radio-over-fiber system, proposed and experimentally demonstrated based on strong injection-locked distributed feedback (DFB) laser. Tunable OCSR value dB achieved by tuning injection detuning frequency precisely. simulation carried out confirm OCSR. Gain properties DFB laser under are also measured first time our knowledge....

In this paper, a novel approach to realize single passband microwave photonic filter (MPF) with wideband tunability based on an optical-injected distributed feedback (DFB) semiconductor laser is proposed and experimentally demonstrated. The fundamental principle the wavelength-selective amplification of DFB under optical injection. frequency tunability, insertion loss, out-of-band suppression ratio MPF are investigated in experiment. By varying injection locking parameters, MPFs tuned from...

A wideband frequency-tunable optoelectronic oscillator using four-wave mixing nonlinear dynamics of an optical-injected distributed feedback (DFB) semiconductor laser is proposed and experimentally demonstrated. Utilizing the wavelength-selective optical gain DFB under injection, a microwave photonic filter realized, which used as desired oscillation frequency selector. Therefore, electrical bandpass not required in scheme. An oscillating signal with tuned from 9.63 to 19.11 GHz obtained by...

A method to enhance the security of optical stealth channel is proposed. The proposed uses techniques polarization modulator based code-shift-keying (CSK) data modulation and code-division multiple-access (OCDMA) en/decoding, where an incoherent light source needed. Our analysis experimental results show that CSK-OCDMA signal, a wavelength selective switch used for has been stealthily transmitted over 40-km wavelength-division multiplexing fiber link. In addition, only causes power penalty...

In this paper, a novel microwave photonic filter (MPF) with multiple independently tunable passbands is proposed. A broadband optical source (BOS) employed and split by 1:N coupler into several branches. One branch directed to phase modulator which modulated radio frequency signal the other branches are delayed delay lines (ODLs), respectively. All of these combined another sent dispersion compensation fiber used introduce group signal. At photodetector, each time-delayed lightwave beating...

Complementary encoder of stealth signal is proposed and demonstrated for coding, modulating enhancing the privacy optical transmission. With complementary encoding, carried by amplified spontaneous emission (ASE) light keeps same characteristic to ASE noise can be concealed well under public channel. The experiment results demonstrate feasibility scheme show has impact on channel in transmission performance, compared noise.

The first semi-quantum noise randomized cipher based on amplified spontaneous emission (ASE) light source employing Y-00 protocol is proposed and demonstrated by a proof-of-principle experiment. As the signal carrier, ASE can provide another fundamental uncertainty, namely, self-beating of signal, which much bigger than quantum shot mesoscopic coherent state also inevitable. By incorporating both beat signals, security will be improved with larger number masked signals (NMS) under intrinsic...

Optical code-division multiple-access (OCDMA) technology is attractive for optical broadband access network. It very interesting to use the super-structure fiber-Bragg-grating-based en/decoders construct a wavelength-division-multiplexing (WDM)-compatible OCDMA system. Based on equivalent phase-shift technique, we have proposed subsampled-Bragg-grating (S-SBG)-based en/decoder. method, only single uniform phase mask can be used accommodate different WDM channels with relevant central...

A novel amplified feedback DFB laser with extended modulation bandwidth is experimentally demonstrated in this paper. All the three sections of cavity, including section, phase and have same active layer, which can avoid butt-joint regrowth process. The gratings both section are fabricated by reconstruction equivalent chirp technique, significantly decrease difficulties realizing precise grating structure. An enhanced −3 dB 19 GHz achieved means a normal low-frequency wafer. Modulation...

Applying the quadrature amplitude modulation (QAM) format, quantum-noise randomized cipher (QNRC) systems hide signal states in quantum phase noise and to prevent eavesdropping. In this paper, based on traditional wire-tap channel model analysis method, physical-layer security of QAM-QNRC system is investigated quantitatively under metric secrecy rate. The general expressions rates data key are derived separately. Furthermore, maximum reachable rate a put forward, which both safe view mutual...

An innovative approach for security-enhanced optical stealth transmission in a synchronous digital hierarchy network is proposed and experimentally investigated. The security enhancement achieved through signal modulation format, so-called polarization-modulated-code-shift-keying, which implemented with two superstructured fiber Bragg gratings-based optical-code-division multiple-access encoders polarization modulator. format can provide constant energy level both bits 0's 1's, avoids secure...

Multi-band linearly frequency-modulated (LFM) signal generation with a multiplying bandwidth is proposed and experimentally demonstrated. It simple photonics method based on the gain-switching state in distributed feedback semiconductor laser without complex external modulator high-speed electrical amplifiers. With N comb lines, carrier frequency of generated LFM signals are times those reference signal. (N number lines.) The bands time-bandwidth products (TBWPs) could be easily adjusted by...