High temperature superconductor subharmonically pumped digital phase modulator/demodulator

Summary form only given. High-temperature superconducting technology along with conventional semiconducting elements has been incorporated into the design of a subharmonically pumped digital phase modulator and demodulator capable of Gb/s transmission rates. The appropriate bandpass filters, stopband filters, and matching networks are fabricated from postannealed double-sided YBa₂Cu₃ O₇ films on 10 mil LaAlO₃. Typically, these films have T_c>90 K, J_c>2×10⁶ A/cm² at 77 K, and surface resistance at 10 GHz and 77 K of ~0.6 Ω/sq. The use of superconducting microstrip filters and matching elements with conventional nonlinear devices provides significant performance improvements, including higher bit rates, lower intersymbol interference, and lower conversion loss than for conventional circuits