No abstract

In this paper, we provide a 5-parameter stacking formula to transform 2-D prestack data into a particular common-offset section. This requires the knowledge of the near-surface velocity only and it is expected that ray theory holds to describe primary reflections. The earth model can be arbitrarily inhomogeneous. The new stacking approach can be viewed as a generalization of the 3-parameter common-reflection-surface (CRS) stack, by which 2-D multicoverage data are stacked into a simulated zero-offset section. The new 5-parameter formula can handle P -P , P -S and S-S reflections.

Building blocks of a scalable and radiation-hardened integrated transmitter unit based on 250 nm SOI,"

A wavelength filter is a key component for numerous photonic integrated circuit applications in optical communication.Researchers put forward several methods to design wavelength filters for which the Echelle grating de-multiplexers (EG-DMUXs) are popular and have been extensively studied.In comparison with the traditional EG-DMUXs based on the Rowland mounting, EG-DMUXs based on the two stigmatic points (TSP) method were reported rather late. This paper will present the basic design theory and a high-performance device fabricated on a 250 nm silicon-on-insulator (SOI) platform for validation. The simulation and measurement results of this 1×7 EG-DMUX with 800 GHz channel spacing will be presented and compared. Although the fabricated device has the merits of compact on-chip footprint, low insertion loss and low crosstalk, its narrow 1-dB bandwidth may limit its application in practice. We present our solution to widen the transmission spectrum based on the TSP EG-DMUXs and multimode interferometers.