An external modulation method is proposed and experimentally demonstrated for the generation of linearly chirped light over broadband with narrow linewidth. Our chirped light source is a combination of an optical recirculating frequency shifter loop and an optical frequency linear sweeper. A linearly chirped light over a range of 200 GHz at a chirp rate of $3.6\times {10}^{16}\mathrm{Hz}/\mathrm{s}$ is generated. The instantaneous linewidth of the chirped light is estimated to be less than 50 kHz.

We describe a scheme for generation of spatial-mode-entangled photon pairs in a few-mode fiber and experimentally demonstrate generation of idler beams from classical seed signals representing various superpositions of fiber LP ₀₁ and LP _11a modes. For every signal mode superposition, we observe the indication of idler mode orthogonality to the signal mode.

We explore the potential of a combination of two fiber parametric wavelength converters and an erbium-doped fiber amplifier to serve as a hybrid amplifier for S-band. We experimentally confirm the validity of a simple quantum model of the wavelength-converter noise figure (NF) and use it to extrapolate the measurement results and find the optimum hybrid amplifier settings. We find that the total NF can be below 6 dB, if the wavelength conversion efficiency of the first stage is above 4 dB. Furthermore, the total NF can be as low as 4 dB, if the conversion efficiency of the first stage is 10 dB or higher. Finally, we estimate the potential impact of pump relative noise on the NF.

Frequency modulation continuous wave (FMCW) lasers are key components in modern optical imaging. However, current intracavity modulation lasers do not exhibit low-frequency jitter rate and high linearity due to the inherent relaxation oscillations. Although this may be compensated in a direct modulation laser diode using an optoelectronic feedback loop, the available sweep speed is moderately small. In this letter, a special external modulation method is developed to improve the performance of FMCW. Since only the first sideband optical field is used during the entire generation process, phase noise is kept to a minimum and is also independent of the sweep speed. We demonstrate that the linearity and jitter rates do not deteriorate appreciably when the sweep speed is changed over three orders of magnitude, even up to the highest sweep speed of 2.5 GHz/μs.

We present a scheme for spatial-mode-selective frequency conversion in a few-mode fiber and experimentally demonstrate upconversion of arbitrary superpositions of LP ₀₁ and LP _11a signal modes from C-band to the fundamental mode in S-band with all conversion efficiencies within 1 dB range of one another.

We experimentally demonstrate a hybrid S-band amplifier, consisting of two parametric-amplifier-based wavelength converters and an L-band EDFA in the middle, and evaluate its performance with 8 WDM channels carrying 10 Gbaud 16-QAM data.