A differential absorption lidar (DIAL) instrument for automated profiling of water vapor in the lower troposphere has been designed, tested, and is in routine operation at Montana State University. The laser transmitter for the DIAL instrument uses a widely tunable external cavity diode laser (ECDL) to injection seed two cascaded semiconductor optical amplifiers (SOAs) to produce a laser transm...

The K-band microelectromechanical systems (MEMS) tunable band-pass filter, with a wide-frequency tunable range and miniature size, is able to fulfill the requirements of the multiband satellite communication systems. A novel 21.69–24.36 GHz MEMS tunable band-pass filter is designed, analyzed, fabricated and measured. This paper also designs and analyzes an inductively tuned slow-wave resonator,...

We demonstrate a silica-based tunable fiber Bragg grating (TFBG) filter with a wavelength tuning range over 60 nm. A magnetically TFBG package is employed to obtain a wide wavelength tuning range from 1540 to 1602 nm which covers the entire C band and most of the L-band. TFBG is achieved by varying an input current to a solenoid, resulting in an electromagnetic force, used as a strain (tension ...

We introduce an off-axis, wide-field, low-coherence and dual-channel interferometric imaging system, which is based on a simple-to-align, common-path interferometer. The system requires no optical-path-difference matching between the interferometric arms in order to obtain interference with low-coherence light source, and is capable of achieving two channels of off-axis interference with high s...

We experimentally demonstrate a novel tunable true-time delay line with separate carrier tuning using dual-parallel Mach-Zehnder modulator and stimulated Brillouin scattering-induced slow light. The phase of the optical carrier can be continuously and precisely controlled by simply adjusting the dc bias of the dual-parallel Mach-Zehnder modulator. In addition, both the slow light and single-sid...

A complex-valued multi-tap tunable microwave photonic filter based on single silicon-on-insulator microring resonator is presented. The degree of tunability of the approach involving two, three and four taps is theoretical and experimentally characterized, respectively. The constraints of exploiting the optical phase transfer function of a microring resonator aiming at implementing complex-valu...

Using the transfer matrix method, the effect of temperature on thetransmission spectra of thermal tunable nano metallic photonic crystal filter has beeninvestigated. Three different materials H (high refractive index material), L (lowrefractive index material) and M as a metallic layer, have been used to make thisstructure. M layer is considered to be Silver. The complex refractive index of Sil...

We demonstrate a tunable narrowband filter based on optical-pumping-induced circular dichroism in rubidium vapor. The filter achieves a peak transmission of 14.6%, a linewidth of 80 MHz, and an out-of-band extinction of >or=35 dB. The transmission peak can be tuned within the range of the Doppler linewidth of the D1 line of atomic rubidium at 795 nm. While other atomic filters work at frequenci...

This paper aims to reveal the relationship between the minimum L2-sensitivity of state-space digital filters and the Gramian-preserving frequency transformation. To this end, we first give a prototype low-pass state-space filter in such a manner that its structure becomes the minimum L2-sensitivity structure. Then we apply the Gramian-preserving (LP-LP) frequency transformation with a tunable p...