The use of optical frequency combs (OFCs) for multi-heterodyne spectroscopy has enabled unprecedented measurement capabilities for spectroscopic sensing, including rapid acquisition speed, high resolution and high sensitivity1,2. Development of field deployable OFC sources that are widely tunable in the important chemical fingerprint region in the long-wavelength infrared (LWIR) is a major research challenge. In this paper, we report our recent efforts towards developing LWIR comb source for SILMARILS (Standoff ILluminator for Measuring Absorbance and Reflectance Infrared Light Signatures) program by IARPA. LGS has developed fiber optic sources producing spectral combs in the SWIR (1.52 to 1.56 μm and 1.7 to 2.0 μm) and in the LWIR (7.7 to 12.1 μm) regions. The spectral combs in the LWIR are generated by difference-frequency mixing one OFC centered around 1.54 μm with another OFC, whose center wavelength is tunable between 1.7 and 2.0 μm, in a nonlinear optical crystal. Average power of the generated LWIR is 1.2-12 mW and its instantaneous spectral breadth of the combs is > 80 cm-1, sufficiently broad to cover multiple molecular absorption peaks. We demonstrate standoff sensing of chemical targets having concentration as low as 12 μg/cm2 by measuring LWIR transflectance spectra using the comb source.
Semiconductor optical amplifiers are important for wide range of applications in optical networks, optical tomography
and optical logic systems. For many of these applications particularly for optical networks and optical logic, high speed
performance of the SOA is important. All optical Boolean operations such as XOR, OR, AND and NOR has been
demonstrated using SOA based Mach-Zhender interferometers (SOA-MZI). A rate equation model for SOA-MZI has
been developed. The model has been used to analyze the Set-Reset (S-R) latch, the gated S-R latch and the D-Flip-Flop
devices. The modeling results suggest that the Flip-Flop circuits should work at high speeds.
We present semiconductor optical amplifier-based optical signal processing for high bit-rate optical communication. All optical wavelength conversion and logic operation of 40-Gb/s PSK and OOK signals are demonstrated. High-speed all-optical signal characterization methods and the application to all-optical signal processing are also presented.
Although the realisation of femtosecond X-ray free electron laser (FEL) X-ray pulses is still some time away, X-ray diffraction experiments within the sub-picosecond domain are already being performed using both synchrotron and laser- plasma based X-ray sources. Within this paper we summarise the current status of some of these experiments which, to date, have mainly concentrated on observing non-thermal melt and coherent phonons in laser-irradiated semiconductors. Furthermore, with the advent of FEL sources, X-ray pulse lengths may soon be sufficiently short that the finite response time of monochromators may themselves place fundamental limits on achievable temporal resolution. A brief review of time-dependent X-ray diffraction relevant to such effects is presented.
Conference Committee Involvement (5)
Next-Generation Optical Communication: Components, Sub-Systems, and Systems IX
5 February 2020 | San Francisco, California, United States
Next-Generation Optical Communication: Components, Sub-Systems, and Systems VIII
6 February 2019 | San Francisco, California, United States
Next-Generation Optical Communication: Components, Sub-Systems, and Systems VII
29 January 2018 | San Francisco, California, United States
Next-Generation Optical Communication: Components, Sub-Systems, and Systems VI
31 January 2017 | San Francisco, California, United States
Next-Generation Optical Communication: Components, Sub-Systems, and Systems V
16 February 2016 | San Francisco, California, United States