Dynamic performance of detuned ridge waveguide AlInGaAs distributed feedback laser diodes

The dynamic behavior of AlInGaAs ridge waveguide distributed feedback lasers is reported in this work covering five detuned wavelengths between 1291 nm and 1326 nm for a laser active layer optical peak gain design centered at 1310 nm at room temperature. The detuning is achieved by modifying the laser grating pitch that performs the mode selection within the laser cavity simultaneously across a single processed wafer. The dynamic behavior is evaluated using the resonance frequencies of the detuned lasers measured at a range of injection currents for heatsink temperatures of 25°C and 85°C. The results confirm that a speed improvement can be achieved at 25°C by detuning the laser to shorter wavelengths. However, the results also show that a lower direct modulation bandwidth at 85°C makes the shorter wavelength design less attractive. For communications applications such as 10 Gbps uncooled operation, this trade-off between detuning and modulation bandwidth imply an optimum around −2 nm to +8 nm detuning (measured at 25°C)

Active V-band modulated backscatter tag

We report the measurement of modulated backscatter produced by a Schottky diode and a printed patch antenna array at V-band (58.75 GHz). The tag was fabricated on a liquid crystalline polymer substrate that is used as the dielectric film and as a carrier for the diode that is wire bonded to the surface of the array. An inexpensive commercial V-band transceiver chipset was successfully used to detect modulated backscatter when the diode was switched at kHz frequencies, demonstrating that the effect is strong enough to be used in commercial applications requiring lightweight, wearable transponders

Modulation accuracy of binary phase-shift keying signal broadcast after injection locking of a resonant tunneling diode microwave oscillator

Injection of a binary phase-shift keyed signal to a resonant tunneling diode (RTD)-based microwave oscillator is presented in this article. The locked signal is broadcast through a wireless communications link and also converted from optical to radio frequency domain using a RTD photodetector. Modulation accuracy is evaluated through error vector magnitude and bit error rate using computer software routines. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:705–711, 2013; View this article online at wileyonlinelibrary.com