All-optical, tunable, V- and W-band microwave generation using semiconductor lasers at period-one nonlinear dynamics with asymmetric mutual injection stabilization.

This study investigates an optically injected semiconductor laser operating at period-one nonlinear dynamics for all-optical microwave generation. A novel, to the best of our knowledge, all-optical stabilization scheme is proposed to greatly enhance the spectral purity of such generated microwaves, which sends a small fraction of the injected laser output back to the injecting laser, not the injected laser itself. Mutual injection with highly different injection power between the two lasers, i.e., highly asymmetric mutual injection, is thus formed. As a result, the microwave linewidth is reduced by up to at least 85 times, the phase noise variance is improved by up to at least 750 times, and a side-peak suppression ratio of more than 44 dB is achieved. Microwave generation that is tunable up to at least 110 GHz with a 3-dB linewidth down to below 2 kHz is realized.

High-entropy chaos generation using semiconductor lasers subject to intensity-modulated optical injection for certified physical random number generation.

This study investigates high-entropy chaos generation using a semiconductor laser subject to intensity-modulated optical injection for certified physical random number generation. Chaos with a continuous spectral profile that is not only widely distributed but also broadly flattened over a bandwidth of 33 GHz is generated. The former suggests that the chaos can be sampled at a high rate while keeping sufficient un-correlation between data samples, and the latter indicates that the chaos possesses high entropy, both of which enhance the generation rate of physical random numbers with guaranteed unpredictability. A minimum entropy value of 2.19 bits/sample is obtained without any post-processing and by excluding the contribution from measurement noise, suggesting that, to the least extent, the chaotic source can be used as a 2-bit physical random number generator at a rate of 160 Gbits/s.

V- and W-band microwave generation and modulation using semiconductor lasers at period-one nonlinear dynamics.

Microwave generation and modulation over the V- and W-bands are investigated using a semiconductor laser subject to both comb-like optical injection and direct modulation. The former not only excites period-one (P1) nonlinear dynamics for tunable microwave generation but also improves the stability and purity of such generated microwaves. The latter upconverts data onto the generated microwaves by superimposing the data effectively only onto the lower oscillation sideband of the P1 dynamics, which prevents the data from dispersion-induced degradation over fiber distribution. As a result, microwaves that are continuously tunable from 40 to 110 GHz with a 3-dB linewidth of less than 1 Hz and with phase noise better than -95dBc/Hz at 10-kHz offset are generated. A bit-error ratio better than the forward error correction limit, 3.8×10-3, is achieved for 12-Gb/s 16-quadrature amplitude modulation data after 25-km fiber distribution.

Broadband chaotic microwave generation through destabilization of period-one nonlinear dynamics in semiconductor lasers for radar applications.

This Letter studies a photonic approach for chaotic microwave generation through destabilization of period-one (P1) nonlinear dynamics in a semiconductor laser subject to intensity-modulated (IM) optical injection. Chaos can be excited when the modulation sideband perturbation carried by the IM optical injection is a few gigahertz higher than the lower oscillation sideband of the P1 dynamics. As a result, chaotic microwaves with a spectral distribution of more than 50 GHz and a bandwidth of about 33 GHz are generated without any time-delay signature or modulation-induced peak. Such features provide the generated chaotic microwaves with preferable characteristics for radar applications, including high detection resolution, superior detection unambiguity, strong anti-jamming capability, and simultaneous multi-band detection.

Frequency-modulated continuous-wave microwave generation using stabilized period-one nonlinear dynamics of semiconductor lasers.

Frequency-modulated continuous-wave (FMCW) microwave generation is studied using a semiconductor laser operating at stabilized period-one (P1) nonlinear dynamics when subject to comb-like (CL) optical injection. The phase locking established between the P1 dynamics and the CL optical injection not only improves the P1 oscillation stability considerably but also provides a mechanism to change the P1 oscillation frequency through varying the modulation frequency of the CL optical injection. As a result, a stable FMCW microwave at a central frequency of up to 40 GHz is generated with its frequency varying linearly, triangularly, or step-wisely over a range of 4 GHz during a repeated time period that can be reconfigured at least from 100 ns to 10 ms. This system is capable of operation up to at least 100 GHz.

Conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation using optically injected semiconductor lasers.

This Letter investigates an optically injected semiconductor laser for conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation. The underlying mechanism relies solely on nonlinear laser characteristics and, thus, only a typical semiconductor laser is required as the key conversion unit. This conversion can be achieved for a broadly tunable frequency range up to at least 65 GHz. After conversion, the microwave phase quality, including linewidth and phase noise, is mostly preserved, and simultaneous microwave amplification up to 23 dB is feasible.