Photon Storage in a Dynamic Two-Ring-Two-Bus System

We propose a novel dynamic two-ring-two-bus system to achieve photon storage. We have demonstrated numerically that the photon can be stopped and released by tuning the ring coupled to two buses in a short time. The two-ring-two-bus system is fabricated on the silicon-on-insulator platform, with the Q factor changing significantly when shifting one resonance. Due to the flexibility and simplicity, it is a promising candidate for the future optical storage and buffering device.

Athermal 4-channel (de-)multiplexer in silicon nitride fabricated at low temperature

We have designed and realized an athermal 4-channel wavelength(de-)multiplexer in silicon nitride(Si N).Minimized thermal sensitivity is achieved in a wide wavelength range by using wide and narrow waveguides with low and different thermal-optic coefficients in the two arms of Mach–Zehnder interferometers(MZIs). The Si N core layer and Si O2 cladding layers are deposited by a low-temperature plasma-enhanced chemical vapor deposition process. The fabricated MZI filter exhibits a thermal sensitivity within 2.0 pm∕°C in a wavelength range of 55 nm to near 1300 nm. Then, an athermal(de-)multiplexer based on cascaded MZIs has been demonstrated with a crosstalk ≤-22 d B and a thermal sensitivity <4.8 pm∕°C for all four channels, reduced by 77% compared to a conventional Si N(de-)multiplexer. Owing to the passive operation and compatibility with the CMOS backend process, our devices have potential applications in 3 D integration of photonics and electronics.

Low-cost hybrid integrated 4 × 25.78 Gb/s CWDM TOSA for 10 km transmission using DFB-LDs and an arrayed waveguide grating multiplexer

We have developed a cost-effective and highly compact 100-Gb/s coarse wavelength division multiplexing(CWDM) transmitter optical subassembly(TOSA) using lens-free hybrid integration. To achieve large alignment tolerances, distributed feedback laser diodes(DFB-LDs) are butt-coupled to a four-channel silica-based planar lightwave circuit(PLC) arrayed waveguide grating, with the silicon sub-mounts and PLC adhesively bonded.Then, a flexible printed circuit is employed to connect the internal DFB-LDs and the exterior of the TOSA package for radiofrequency signal transmission, eliminating the expensive ceramic feed-through. The packaged CWDM TOSA, which is 15.8 mm × 7.0 mm × 6.0 mm in size, shows a side-mode suppression ratio of>40 dB, a 3 dB bandwidth of >18 GHz, and error-free transmission with an average optical output power of >0 dBm and dynamic extinction ratio of >4.0 dB at 25.78125 Gb/s over a 10 km single-mode fiber for all four lanes.

Proposal and demonstration of a controllable Q factor in directly coupled microring resonators for optical buffering applications

Optical resonators with controllable Q factors are key components in many areas of optical physics and engineering.We propose and investigate a Q-factor controllable system composed of two directly coupled microring resonators,one of which is tunable and coupled to dual waveguides.By shifting the resonance of the controllable microring,the Q factor of the system as well as the other microring changes significantly.We have demonstrated wide-range controllable Q factors based on this structure in silicon-on-insulator,for example.The influences of spectral detuning and coupling strength between two resonators on the variation of Q factors are studied in detail experimentally.Then,we explore its applications in optical buffering.Tunable fast-to-slow/slow-to-fast light has been carried out by switching the system between the high-Q state and low-Q state.Moreover,optical pulse capture and release are also achievable using this structure with dynamic tuning,and the photon storage properties are investigated.The proposed Q-factor tunable system is simple,flexible,and realizable in various integrated photonic platforms,allowing for potential applications in on-chip optical communications and quantum information processing.