On the basis of a self-pulse feedback mechanism, an ultralow-time-jitter and flexible repetitious rate optical pulse generator module with a simple and compact design was developed. Using a compact design self-seeding distributed feedback laser diode module, a low time jitter pulse on the order of sub-picoseconds was successfully observed within any modulation frequency range from 1 to 2 GHz. A pulse compression technique based on the nonlinear effect in optical fiber was used. A pulse width of 1.9 ps and a jitter of 0.5 ps were obtained with neither waveform degradation nor jitter increase.
The recent start of R&D into Wireless Personal Networks (WPAN) and millimeter-wave wireless systems is creating an urgent need for development of a spectrum analyzer supporting accurate measurements in the frequency band above 100 GHz. However, there is no spectrum analyzer with a built-in pre-selector supporting spectrum analysis of wireless signals above 67 GHz. Such measurement is made generally by connecting a harmonic mixer or Block Down converter externally to a spectrum analyzer. In this case, generated unwanted signal components (spurious responses) are often seen during measurement, making it difficult to monitor the original signal components. This paper proposes development of a millimeter-wave spectrum measurement system incorporating a pre-selector function for wide dynamic range measurements with minimum unwanted signal components. We present the results of investigation into a prototype of the proposed system. We also measured a 120 GHz QPSK modulation wave to demonstrate the effectiveness of this system with pre-selector.
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