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...

Cavity optomechanics is concerned with the interaction between optical cavities and mechanical resonators. Here, we present systematic research on dynamic behaviors of cavity optomechanical systems incorporating influence thermal nonlinearity. A dimensionless theoretical model was established to describe system numerical simulations were performed study behaviors. We theoretically identify staircase effect, which can abruptly alter parameters when adiabatically sweeping pump laser frequency...

In this paper, a novel approach for generating flat optical frequency comb (OFC) based on externally injected gain-switched distributed feedback (DFB) semiconductor laser is proposed and experimentally demonstrated. the system, flatness, number of OFC spectral lines, line to background noise ratio can be tuned their optimized values by adjusting current modulation signal, injection detuning frequency. Since signal decides spacing output lines different achieved. experiment, 10 with 1.5 dB...

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 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...

Amplified spontaneous emission (ASE) light is the most natural optical carrier to hide a message in existing networks at photonic layer. To enhance anti-intercept ability of ASE-carried stealth channel, novel communication scheme based on quantum noise stream cipher proposed. The ASE intensity modulated by cipher-text according Y-00 protocol, and then transmitted under public after power attenuation. expression ciphered signal derived, numerical simulation carried out. A proof-of-concept...

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.

In optical covert communication systems based on gain-switched distributed feedback semiconductor lasers, the trade-off between modulation frequency and spectral imperceptibility limits bit rate of secure channel. To improve system performance in terms covertness, time-division multiplexing is introduced to for first time. The multiplexed channel can work under both multiple-user single-user conditions. demonstrated via a simulation. results show that covertness enhanced by domain. receiver...

Amplified spontaneous emission (ASE) light is a common noise in optical communication systems with amplification, and suitable carrier for covert communication. To deeply the secure signal, an in-band subnoise scheme proposed demonstrated by proof-of-concept experiment. The power spectral density of channel 10 dB less than public channel. signal hidden both electrical domain, can be transmitted error-free. trade-off between covertness availability discussed.

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...

To provide secure and covert transmission for optical communication system at the same time, a quantum-noise stream ciphered stealth approach is proposed first time. In system, pulses are time spread by chromatic dispersion device then phase modulated with codes chip rate to realize an equivalent spectral encoding. Binary converted multiple level phase-shift keying signal according Y-00 protocol. The encoded signals attenuated mesoscopic coherent states sent public channel. stealthy...

A novel microwave photonic filter (MPF) based on carrier-suppressed single sideband (CS-SSB) injected distributed feedback (DFB) laser is proposed. The proposed MPF system exploits the frequency selective gain feature of optical DFB lasers, which can be tuned by adjusting injection parameters or working conditions laser. Therefore, tunable. verified a proof-of-concept experiment, and results show that passband tuning ratio bias current slave laser, where range 9–39 GHz realized. At same...

We propose and experimentally demonstrate an optical stealth transmission system over a 200 GHz-grid wavelength-division multiplexing (WDM) network. The signal is processed by spectral broadening, temporal spreading, power equalizing. public suppressed multiband notch filtering at the channel receiver. interaction between channels investigated in terms of public-signal-to-stealth-signal ratio, data rate, notch-filter bandwidth, number. can transmit 80 km single-mode fiber with no error. Our...

A novel kind of Fabry-Pérot (FP) structure based on chirped sampled fiber Bragg grating (CSFBG) is proposed and demonstrated. In this structure, the regular FBG (CFBG) that functions as reflecting mirror in FP cavity replaced by CSFBG, which realized chirping sampling periods a having uniform local period. The realization such CSFBG-FPs diverse properties just needs single pitch phase mask sub-micrometer precision moving stage. Compared with conventional CFBG-FP, it becomes more flexible to...

A novel thresholder based on cross-gain modulation (XGM) effect in a distributed-feedback (DFB) semiconductor laser combined with offset optical filtering is proposed and demonstrated. To the best of our knowledge, this first XGM effect-based that operated by injection DFB laser. In scheme, without an isolator key component, which costs less than nonlinear devices required other schemes. The spectrum output from can be broadened after pulses injected to cavity, induced effect. Only correct...

The performance of an optical stealth transmission system based on gain-switched laser depends largely the parameters. Modulation frequency, bias current, and modulation current are considered to study covertness bit error rate system. According carrier generation with time spreading all-optical encoding, signals derived. A complementary encoding scheme is adopted in simulation. simulation results show that temporal spectral characteristics generated signal can be changed by adjusting...

This paper proposes a tunable multiple-passband microwave photonic filter (MPF) that is incorporated with an injection-locked Fabry-Pérot (FP) laser.In the proposed MPF, multiple passbands can be easily generated based on frequency-selection effects of laser structure in case light waves injection.The novelty here obtained MPF achieve either dual-passband or single-passband by using merely one experimental scheme.Moreover, since injection ratio scheme high, central frequency each passband...

Quantum-Noise Randomized Cipher (QNRC) is a potentially information-theoretic secure physical-layer encryption method for high-speed and long-distance fiber communications. In order to solve the problem that modulation demodulation of M-ary Y-00 ciphertext signal in QNRC system are limited by ADC chip with high sampling rate conversion depth, novel realization PSK-QNRC based on series structure multiple phase modulators (PM) proposed, performances proposed scheme verified using commercial...

An ultra simple and low cost method to detect low-power RF signal is proposed experimentally demonstrated based on optoelectronic feedback DFB semiconductor laser. To our knowledge, according public reports, this the simplest photonics-assisted which avoids using high sensitive optical modulators narrow bandwidth filters. The signal, matches oscillation mode at relaxation peak of laser, amplified feedback. from 1 4.5 GHz can be detected by adjusting frequency related laser bias current....