Subharmonic injection‐locking balanced oscillator

Abstract

a 40-Gb/s linear channel. The optical preamplifier includes a dispersion compensator with a dispersion compensation fiber (DCF) and a tunable dispersion compensator (TDC). The TDC gives the precise dispersion compensation and minimizes the dispersion induced power penalty. Therefore, perfect dispersion compensation is achieved in the 40-Gb/s optical link. A clock-recovery circuitry, consisting of an EX-OR block and a dielectric resonator, was used for the 40-GHz clock extraction. In order to demultiplex the 40-Gb/s signal into four channels of 10-Gb/s tributary signals, a 1:4 electrical demultiplexer was used. The demultiplexer has four sets (D0 -D3) of data and data-bar outputs, a clock, and clock-bar outputs. After demultiplexing the signal, we measured the bit-error rate at the 10-Gb/s level using an error detector. Figure 4 represents the bit-error rate characteristics for 10-Gb/s tributary signals (D0 -D3). The average receiver sensitivity at BER 10 Ϫ12 was Ϫ23.5 dBm in the back-to-back configuration (solid marks). After the 219-km transmission (open marks), the sensitivity was degraded to Ϫ23 dBm. The power penalty was only 0.5 dB and all the tributary channels showed nearly the same performance. The achieved transmission distance of 219 km without the fiber Raman amplifier and FEC in the 40-Gb/s field trial is competitive with the previous reports in the literature [5,6]. Figure 5 shows the eye patterns. EXPERIMENTAL RESULTS CONCLUSIONWe have developed a 40-Gb/s ETDM prototype and demonstrated a 219-km field trial of KT's field-installed single-mode fiber in the Daejeon area. The prototype does not adopt the fiber Raman amplifier and FEC, but uses only conventional EDFAs and precisedispersion compensation. Therefore, a practical and economical field trial of the 40-Gb/s ETDM prototype was achieved. After SMF transmission 219 im, the power penalties of 0.5 dB for four 10 Gb/s tributary channels were obtained. We have concluded that the actual fiber infrastructure in Korea is adoptable for transmission of the 40 Gb/s signal.

Optimal sub‐harmonic injection‐locked MICS band transmitter for wireless CW‐fNIRS systems

“…The transmitter schematic with details included PCO, duty cycle reducer, CSRO under SHIL, and power amplifier challenge of power consumption has led to a lot of research into injection locking from 2003. [39][40][41][42] In addition to a significant reduction in phase noise, this method will increase the oscillator's reliability versus temperature changes and manufacturing process parameter variations.…”