To realize a reservoir computing system with a small size and reduced learning cost, provided is a laser apparatus including a laser; a feedback waveguide that is operable to feed light output from the laser back to the laser; an optical splitter that is provided in a path of the feedback waveguide and is operable to output a portion of light propagated in the feedback waveguide to outside; and a first ring resonator that is operable to be optically connected to the feedback waveguide, as well as a reservoir computing system including this laser apparatus.

A driver circuit includes: a variable power supply configured to apply a power supply voltage to a light emitting device and to vary a voltage value of the power supply voltage; a current-control switching device electrically connected to the light emitting device and configured to control a current flowing in the light emitting device; a detection part configured to detect a current value and a voltage value related to the current flowing in the light emitting device; and a control part configured to determine a minimum voltage of the power supply voltage based on a detection result of the detection part.

A laser diode control circuit includes: a LD driver circuit for driving a laser diode; a direct current component remover circuit for generating a feedback signal based on a detected signal; a first conversion and filter circuit for generating a first filtered signal based on the feedback signal; a first rectifier for rectifying the first filtered signal to generate a first rectified signal; a reference signal generator for generating a reference signal; a second conversion and filter circuit for generating a second filtered signal based on the reference signal; a second rectifier for rectifying the second filtered signal to generate a second rectified signal; a rectified signals processing circuit for generating a processed signal based on the first and second rectified signals; and a comparator for generating a comparison signal based on the processed signal.

The present disclosure provides a unique digitally integrated, self-trained pre-distortion curve generation method and apparatus for semiconductor lasers (SCLs) to generate linearly swept optical signals that are applicable to a wide range of sweep velocities and semiconductor laser types. The method requires no prior knowledge of the frequency response of the laser and is highly accurate.

The present disclosure provides methods and apparatus to improve the dynamic coherent length of a sweep velocity-locked laser pulse generator (SV-LLPG) in an all-electronic fashion. A digital SV-LLPG is disclosed with two operation modes, i.e., unidirectional and bidirectional sweep modes; self-adaptive and time-dependent loop parameters (gain and location of poles/zeros); and, self-adaptive initial input curve. High frequency locking architectures, both single-side band (SSB) modulation method and direct phase measurement method, are provided to suppress the linewidth, or improve the coherent length, of the swept laser. A combination of high and low frequency locking, or a combination of multiple architectures disclosed in this invention, is utilized to achieve a higher level of linewidth reduction. The enhanced laser coherence extends the measurement range by at least one order of magnitude for applications including frequency-modulated continuous wave (FMCW) light detection and ranging (LiDAR) and optical fiber distributed sensing applications.

The present disclosure provides methods and apparatus to improve the dynamic coherent length of a sweep velocity-locked laser pulse generator (SV-LLPG) in an all-electronic fashion. A digital SV-LLPG is disclosed with two operation modes, i.e., unidirectional and bidirectional sweep modes; self-adaptive and time-dependent loop parameters (gain and location of poles/zeros); and, self-adaptive initial input curve. High frequency locking architectures, both single-side band (SSB) modulation method and direct phase measurement method, are provided to suppress the linewidth, or improve the coherent length, of the swept laser. A combination of high and low frequency locking, or a combination of multiple architectures disclosed in this invention, is utilized to achieve a higher level of linewidth reduction. The enhanced laser coherence extends the measurement range by at least one order of magnitude for applications including frequency-modulated continuous wave (FMCW) light detection and ranging (LiDAR) and optical fiber distributed sensing applications.

To realize a reservoir computing system with a small size and reduced learning cost, provided is a laser apparatus including a laser; a feedback waveguide that is operable to feed light output from the laser back to the laser; an optical splitter that is provided in a path of the feedback waveguide and is operable to output a portion of light propagated in the feedback waveguide to outside; and a first ring resonator that is operable to be optically connected to the feedback waveguide, as well as a reservoir computing system including this laser apparatus.

A diode control device include a first terminal for receiving a first power supply voltage and a second terminal for receiving a second power supply voltage. A circuit of the diode control device applies a regulated voltage on the anode of the diode in response to a control voltage. The control voltage is equal to a preset voltage when a reference voltage is less than or equal to zero. Conversely, when the reference voltage is greater than zero, the control voltage is equal to the sum of the present voltage and a difference between cathode voltage of the diode and the reference voltage.

A diode control device include a first terminal for receiving a first power supply voltage and a second terminal for receiving a second power supply voltage. A circuit of the diode control device applies a regulated voltage on the anode of the diode in response to a control voltage. The control voltage is equal to a preset voltage when a reference voltage is less than or equal to zero. Conversely, when the reference voltage is greater than zero, the control voltage is equal to the sum of the present voltage and a difference between cathode voltage of the diode and the reference voltage.

An optical amplification device includes: a semiconductor optical amplifier; a first detector that detects an input optical power of the semiconductor optical amplifier; a second detector that detects an output optical power of the semiconductor optical amplifier; and a controller that controls a driving current of the semiconductor optical amplifier, wherein the controller supplies a predetermined driving current to the semiconductor optical amplifier when an optical signal is not input to the semiconductor optical amplifier, the second detector detects an optical power of Amplified Spontaneous Emission (ASE) output from the semiconductor optical amplifier when the predetermined driving current is supplied to the semiconductor optical amplifier, and the controller controls the driving current of the semiconductor optical amplifier based on the input optical power of the semiconductor optical amplifier detected by the first detector, and the optical power of the ASE.