Simultaneous multichannel RZ to NRZ format conversion for LP and LP using a few-mode fiber Bragg grating.

We propose a novel format conversion scheme, which can implement multichannel format conversion from return-to-zero (RZ) to non-return-to-zero (NRZ) for both LP and LP simultaneously by designing a few-mode fiber Bragg grating (FM-FBG) with comb spectra. To achieve filtering for all channels of the two modes, the FM-FBG response spectra of LP is designed to shift with that of LP by the WDM-MDM channel spacing. This approach is realized by carefully selecting the specifications of the few-mode fiber (FMF) to fulfill the requirements of the effective refractive index difference between LP and LP.

Real-time digital compensation to reduce acceleration's sensitivity in quartz resonator.

The paper presents a digital compensator imposing real-time voltage to compensate the frequency offset of quartz resonator under acceleration. To begin with, a triple-axis MEMS acceleration sensor, whose package is less than 3 mm × 3 mm × 0.9 mm, is mounted at the bottom of quartz resonator.