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1

Investigation of a tunable and switchable multi-wavelength bidirectional Brillouin-erbium fiber ring laser

Wang F., Yuan R. Y.

Optica Applicata

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2021

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Vol. 51, nr 3

375--389

EN

A multi-wavelength bidirectional Brillouin-erbium fiber ring laser with switchable Brillouin frequency spacing (BFS) is proposed and experimentally demonstrated. In the presented Brillouin-erbium ring laser, including an optical amplifier and a highly nonlinear fiber, and without any optical isolator, due to Rayleigh scattering, stimulated Brillouin scattering, and cascaded four-wave mixing initiated successively by the Brillouin pump (BP) light, the odd- and even-order Stokes lines are generated and circulate in the opposite direction in the ring cavity. The BP light and Stokes-induced Rayleigh backscattering light also simultaneously circulate in the ring cavity. Only by adjusting BP power, the gain competition between Brillouin based Stokes and cavity modes’ oscillation can be controlled, the laser output can be conveniently switched between single BFS and odd- or even-order double BFS. In addition, under the certain BP power conditions, the proposed multi-wavelength Brillouin-erbium fiber laser also can realize switchable odd- or even-order Stokes generation and Stokes generation with single BFS, with an increasing wavelength number in turn, only by simply adjusting pump power of the erbium-doped fiber amplifier. Stability and wavelength tunability of the proposed multi-wavelength bidirectional Brillouin-erbium fiber ring laser are also investigated, respectively.

2

Photonic generation of broadly tunable radio-frequency signal using a reflective semiconductor optical amplifier

Lu Youxi, Wang Fei, Gu Jun, Shi Lun, Peng Mengmeng, Huang Jingxin, Kang Wen

Optica Applicata

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2019

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Vol. 49, nr 1

27--36

EN

A novel scheme for photonic generation of broadly tunable radio frequency signal using a reflective semiconductor optical amplifier (RSOA) is demonstrated. A continuous wave emitted from the laser diode is modulated by a Mach–Zehnder modulator, then the modulated optical carrier is injected into the RSOA. Due to the four-wave mixing effect in the RSOA, the limited frequency components of the modulated signal are expanded, which directly lead to the generation of a wide frequency comb. Two optical tunable bandpass filters are parallelly connected to select the desired sidebands, which are launched into a photodetector or photomixer to generate radio frequency signal by beating. Using the proposed method, the bandwidth of generated radio frequency signal can range from 20 to 300 GHz.

3

Side-pumped neodymium laser with self-adaptive, nonreciprocal cavity

Kaskow M., Galecki L., Zendzian W., Gorajek L., Jabczynski J. K.

Opto-Electronics Review

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2016

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Vol. 24, No. 1

10--14

EN

We demonstrate the generation of a near-diffraction-limited beam in a diode-side-pumped Nd:YAG slab laser with a nonreciprocal, self-adaptive cavity. The energy output of 228 mJ with 17.2% slope efficiency and 17.3% optical-to-optical efficiency was obtained.

4

Optical waveform monitoring based on a free-running mode-locked femtosecond fibre laser and four-wave mixing in a highly nonlinear fibre

Liu Y., Zhang Y. G., Tang D.

Opto-Electronics Review

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2016

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Vol. 24, No. 2

62--74

EN

Optical sampling based on ultrafast optical nonlinearities is a useful technique to monitor the waveforms of ultrashort optical pulses. In this paper, we present a new implementation of optical waveform sampling systems by employing our newly constructed free-running mode-locked fibre laser with a tunable repetition rate and a low timing jitter, an all-optical waveform sampler with a highly nonlinear fibre (HNLF), and our developed computer algorithm for optical waveform display and measurement, respectively. Using a femtosecond fibre laser to generate the highly stable optical sampling pulses and exploiting the four-wave mixing effect in a 100m-long HNLF, we successfully demonstrate the all-optical waveform sampling of a 10GHz optical clock pulse sequence with a pulse width of 1.8 ps and a 80Gbit/s optical data signal, respectively. The experimental results show that waveforms of the tested optical pulse signals are accurately reproduced with a pulse width of 2.0 ps. This corresponds to a temporal resolution of 0.87 ps for optical waveform measurement. Moreover, the optical eye diagram of a 10Gbit/s optical data signal with a 1.8 ps pulse width is also accurately measured by employing our developed optical sampling system.

5

All optical measurement of an unknown wideband microwave frequency

Kumar A., Priye V., Raj Singh R.

Opto-Electronics Review

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2016

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Vol. 24, No. 4

191--195

EN

A novel all optical measurement scheme is proposed to measure wideband microwave frequencies up to 30 GHz. The proposed method is based on a four-wave mixing (FWM) approach in a semiconductor optical amplifier (SOA) of both even order side-bands generated by an unknown microwave frequency modulating an optical carrier. The optical power of a generated FWM signal depends on frequency spacing between extracted side-bands. A mathematical relation is established between FWM power and frequency of an unknown signal. A calibration curve is drawn based on the mathematical relation which predicts the unknown frequency from power withdrawn after FWM.

6

Optical Josephson effects using phase-conjugating mirrors: an analogy with superconductors

Blaauboer M., Lenstra D., Lodder A.

Journal of Telecommunications and Information Technology

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2000

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nr 1-2

24-28

EN

Motivated by the analogy between a phase-conjugating mirror (PCM) and a superconductor, we search for optical counterparts of the well-known DC and AC Josephson effects. We show that in a system consisting of two PCM's separated by vacuum an 'optical supercurrent' arises as a function of an applied phase difference between the PCM's, which is the optical analogue of the DC supercurrent flowing in a superconducting weak link. The corresponding AC effect occurs when the two PCM's are pumped by light of a different frequency, causing the phase difference to oscillate in time with the frequency difference.

7

Nonlinear optics of the thin-film quasiwaveguide amplifier: applications to directional switching in the optical communication systems

Djotyan G.P., Arutunyan V.M., Bakos J.S., Sörlei Z.

Journal of Telecommunications and Information Technology

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2000

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nr 1-2

20-23

EN

We examine nonlinear optical effects in the active medium of the thin-film quasiwaveguide amplifier-oscillator with injection of the external signal. The injection locking has been obtained in the case when both the frequency and the direction of propagation of the injected signal differ from those for a free-running thin-film laser which offers a possibility for the frequency and directional switching of the output of the thin-film laser. The effects of four wave mixing and phase conjugation have been discussed in the active medium of the thin-film laser when additional mirrors forming an external resonator have been used.