Electronics Letters: volume 46 issue 21

Featured article

Dropping through the floor

The first significant reduction in the noise floor of quartz crystal oscillators for 15 years has been achieved by a European collaboration.

Also in this issue

• Interview with Fabrizio Lombardi

  Professor Fabrizio Lombardi from Northeastern University in the US tells us about the work behind the Letter Modelling and extracting parameters of organic solar cells.

• Vivaldi steps up a notch

  A reconfigurable antenna that can switch its operation between three different modes is showing promise for future cognitive radio systems.

• An ear for gas

  Researchers in China have created a nerve gas sensor based on a film bulk acoustic resonator. The sensor displays gas sensitivity up to 80 kHz/ppm: orders of magnitude higher than a quartz crystal microbalance. The device also has advantages in the simplicity of its fabrication process and its compact size which make it appropriate for handheld sensors and sensor arrays to provide analysis of multiple targets simultaneously.

• Power switch

  Using a silicon wire waveguide integrated with a Ge₂Sb₂Te₅ thin film, Japanese researchers have realised an optical gate capable of switching in both directions. Consequently, their switch requires no continuous power to maintain the switching state and will enable drastic reduction of power consumption and transmission latency in broadband network systems.

• Here be dragons

  US researchers show the limits of long-wavelength interband semiconductor laser diodes operating in CW at room temperature have yet to be reached. Through optimisation of the waveguide design they have extended the operation of type-I quantum well lasers in this regime above 3.4 μm. Compact, robust, requiring low operating voltage and potentially low cost, such lasers have applications from trace gas spectrometry to infrared countermeasures.

• Air bridge

  Low-loss free-space optical transmission via a planar silica lens pair has been demonstrated by researchers in Australia. Use of such a lens pair to transmit light between silica optical waveguides, key elements in photonic circuits and optical MEMS devices, has previously been theoretically studied for application in optical cross-connect switches and interconnects. Confirming theory, the results show loss reductions as high as 12.4 dB.

• Short shifting

  A design method to optimise the length of a MEMS phase shifter while maintaining practical return losses has been demonstrated by researchers from China. The fabricated phase shifter does not experience performance degradation, and its simplicity, compact size, and low pull-down voltage make it suitable for phased-array antennas in X-band radar systems.