On-chip long Josephson junction (LJJ) clock technology

An oscillator circuit comprising:

• a long Josephson Junction (LJJ);
• means for supplying a bias current to the LJJ;
• means for supplying a control current and magnetically coupling the current to the LJJ for causing the generation of pulse signals within the LJJ;
• and
• at least one tap connected to the LJJ for obtaining pulse signals from the LJJ.

An oscillator circuit comprising:

• an undamped long Josephson junction (LJJ) having a hysteretic current-voltage (I-V) characteristic;
• current biasing means for supplying a bias current to the LJJ for increasing the junction current above its critical value and causing the LJJ to switch from the superconductive state to a resistive state along a first step, said current biasing means also including means for selectively decreasing the junction current to a predetermined value, above zero, and then increasing the junction current to cause the LJJ to switch to the normal state along a path other than said first step for varying and controlling the frequency of oscillation;
• and
• at least one connection to the LJJ for obtaining pulse signals from the LJJ.

A combination comprising:

• a long Josephson junction (LJJ) oscillator;
• a single flux quantum (SFQ) circuit having an input and an output;
• means for applying a time varying voltage waveform to the input of the SFQ circuit for causing the SFQ circuit to generate a pulse at its output;
• a Josephson transmission line (JTL) having an input and an output;
• said JTL being connected at its input to the output of the SFQ circuit for propagating a pulse generated by the SFQ circuit and producing a pulse corresponding thereto at said JTL output;
• a buffer circuit having an input and an output, said buffer including means for propagating a pulse unidirectionally from its input to its output;
• and
• means connecting the input of the buffer to the output of the JTL and the output of the buffer to the LJJ oscillator for controlling the oscillation of the LJJ oscillator in response to the receipt of a pulse from the SFQ circuit.