Line-scanning technique using a PDMS grating in a microscope configuration.

We report the concept of a 1550 nm laser line scanning microscope based on a polydimethylsiloxane (PDMS) grating with scanning by stretching the PDMS grating to improve the scanning speed and enable low-cost scanning. Zemax is used to verify the possibility of realizing the system by simulating the illumination light path and the emission light path. The scanning field of view is 0.11m m×0.11m m, and the modulation transfer function (MTF) data of the 0th, ±1st, and ±2 nd diffraction orders in the illumination light path and the emission light path, respectively, meet the requirements of the diffraction limit resolution at the cutoff frequencies.

Reducing phase noise coupled by wavefront errors in optical telescopes for the space measurement of gravitational waves.

Space-based gravitational-wave observatories (SGOs) promise to measure pico-meter variations in gigameter separations of a triangular constellation. Telescopes play an essential role in transmitting and receiving laser beams measuring the constellation arms with the heterodyne laser interferometry. The wavefront aberrations of the telescopes are coupled with the unavoidable misalignments caused by jitters and pointing tilts and induce additional phase changes into the heterodyne signal. As a critical aspect of achieving the measuring stability of 1p m/H z, we analytically investigate the above process and determine that by properly controlling the relevant key aberrations in the design of the telescopes, the phase noise can be reduced exponentially, which makes the heterodyne signal insensitive to jitter and reduces the demand for wavefront quality. This method is validated whether the LISA Pathfinder (LPF) signal definition or the Average Phase (AP) signal definition is adopted, underpinning the guidance for the design and manufacturing of the optical telescope in SGOs.

Transmission performance of a 1.96 µm active mode-locked laser in smoke channel.

We demonstrate the data transmission characteristics of a 1.96 µm laser in an indoor simulated smoke channel. An active mode-locked thulium-doped fiber laser at 1961.63 nm can be generated, and the repetition rate is 2.11 GHz corresponding pulse duration of 12.47 ps. Therefore, the pulse can be modulated by a 2.11 Gb/s digital sequence to act as a carrier light source. The transmission characteristics of signal light under different visibility conditions of 0.5, 0.05, and 0.005 km are studied. Compared with the back-to-back conditions, the signal-to-noise ratios of the carrier can decrease after passing through the smoke channels, which are 3.93, 7.1, and 9.08 dB, respectively. At the same time, the received power jitter can increase from ±0.16 to ±1.14dB. The sensitivity can be -19.52dBm at the visibility of 0.005 km. The experimental results show that thulium-doped mode-locked laser has an excellent performance in a smoke channel.

1.9 µm all-optical wavelength converter based on a graphene oxide coated microfiber.

An all-optical wavelength converter based on graphene oxide (GO) is proposed at the 1.9 µm band. The homemade GO-coated microfiber is acquired through the optical deposition method, which shows a remarkable nonlinear optical response. Stable conversion efficiency up to -45.52 dB is obtained with 1 nm wavelength interval, and the wavelength tuning range can reach 6 nm (1969-1975 nm). With fixed wavelength interval, the conversion efficiency can increase with the increase of pump power. Simultaneously, the fluctuation of conversion efficiency is ±0.41 dB within 2 hours. The demonstrated all-optical wavelength converter based on GO can play an outstanding role in the future of all-optical communications and networks.