Silicon waveguide modulator based on carrier depletion in periodically interleaved pn junctions, Opt Express 17 (2009), 15947-15958.ABSTRACT: A novel compact microstrip dual-mode dual-band bandpass filter using two symmetrical twin-inductor resonators for I-band application is proposed. Double twin symmetrical rectangular-shaped inductors are connected with the stepped-impedance resonator terminals for matching 50 X impedance. The two twin-inductor ends are connected to ground with via connections. The two opposite inductors are joined and become twin-inductor structure that also behaves as an inductorinterdigital coupling. The combination of the two those twin-inductor interdigital structures give strong inductive couplings between the two ports and develop a fixed resonance frequency. This filter is designed to operate at 8.1 GHz and 10.7 GHz resonant frequency with a 20.98 and 13.08% effective bandwidth, respectively, at the 3-dB passband. More than 20 dB spurious suppression was measured in between two distinct bands. The measured insertion loss (S 21 ) was less than 1 dB recorded for both bands and return loss (S 11 ) was more than 21 dB measured at center operating frequencies of both bands. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:638-641, 2012; View this article online at wileyonlinelibrary.com.

We proposed and experimentally demonstrated wavelength division (de)multiplexers (WDMs) utilizing the wavelength dispersive nature of self-imaging multimode interferometers. Proof-of-principle devices fabricated on the silicon-on-insulator platform operated as 4-channel WDMs with a free spectral range of >90 nm, an averaging cross talk of <-20 dB for a 1 nm band, and an insertion loss of <2.0 dB. The potential for higher channel counts and smaller channel wavelength spacing was also predicted. This type of WDM is easy to design and fabricate. The underlying concept is applicable to all planar waveguide platforms.

We report the demonstration of novel GaAs/AlGaAs integrated optical 1-to-N way beam splitters which use symmetric mode mixing in center-fed multimode planar waveguides. Each device has one single-mode input guide, a carefully chosen length of parallel sided multimode guide, and N equally spaced single-mode output guides. The mixing of symmetric modes shares the input light equally between the output guides by a symmetric form of the self-imaging process. We demonstrate experimentally that this type of beam splitter can be used to divide power equally, with high accuracy and low loss, between the N output guides, for values of N between 2 and 20.

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An integrated optic approach, using hollow waveguides, has been evaluated for a compact, rugged, high efficiency heterodyne optical mixing circuit in the middle infrared. The approach has involved the creation of hollow waveguides and alignment features for a beam combiner component in a glass-ceramic substrate. The performance of the integrated beam combiner was tested as part of a full laser heterodyne spectro-radiometer in which a quantum cascade laser local oscillator emitting at 9.7 µm was mixed with incoherent radiation. The performance has been evaluated with both cryogenically-cooled and peltier-cooled photomixers demonstrating consistent detection limits of two and five times the shot noise limit, respectively. The hollow waveguide mixer has also shown advantages in temporal stability, laser spatial mode cleansing, and reduced sensitivity to optical feedback.