Conventional angle-tuned thin-film filters have serious angle sensitivity for their low spacer effective refractive index, and it is difficult to fabricate their angle control system. In this paper, we propose and fabricate a novel 100 GHz angletuned thin-film filter stack with low angle sensitivity, which uses the high refractive index material TiO2 as the spacer, and its incident angle can be expanded to 25°. Compared with the traditional Ta2O5-SiO2 thin-film filter stack, the novel stack has fewer layers. Using the polarization beam splitters and the half wave plates, the polarization sensitivity of the angle-tuned filter can also be suppressed. Simulation results and the experiments show that the thin-film filter with low angle sensitivity has an effective tuning range of 33 nm, which can cover the whole C-band, and its angle control system is easy to be fabricated.
The rectangular optical filter is one of the most important optical switching components in the dense wavelength division multiplexing(DWDM) fiber-optic communication system and the intelligent optical network. The integrated highorder silicon microring resonator(MRR) is one of the best candidates to achieve rectangular filtering spectrum response. In general, the spectrum response rectangular degree of the single MRR is very low, so it cannot be used in the DWDM system. Using the high-order MRRs, the bandwidth of flat-top pass band, the out-of-band rejection degree and the roll-off coefficient of the edge will be improved obviously. In this paper, a rectangular optical filter based on highorder MRRs with uniform couplers is presented and demonstrated. Using 15 coupled race-track MRRs with 10 μm in radius, the 3 dB flat-top pass band of 2 nm, the out-of-band rejection ratio of 30 dB and the rising and falling edges of 48 dB/nm can be realized successfully.
With the development of the optics communication system and optical signal modulation technology, the amplitude-shift keying (ASK) and phase-shift keying (PSK) are both used in different optical communication sub-networks. In this paper, a novel all-optical modulation format from PSK to ASK based on phase-sensitive amplification is proposed and demonstrated. Using the nonlinear interference of the single-pump phase-sensitive amplification, the signal wavelength can be preserved while the modulation format is conversed. The proposed scheme provides the flexible intermediate node interface transformation in future optical networks.
