SEMICONDUCTOR OPTICAL AMPLIFIER LASER DIODE SYSTEM
A system includes a laser diode configured to produce seed light, a capacitor configured to charge from a voltage source, a transistor configured to control current flowing through a semiconductor optical amplifier via a controlled discharge of the capacitor, the semiconductor optical amplifier configured to amplify at least a temporal portion of the seed light in response to the current flowing through the semiconductor optical amplifier to emit an output pulse of light, and a receiver configured to detect at least a portion of the output pulse of light scattered by a target object located at a distance from the system.
1 . A system, comprising:
a laser diode configured to produce seed light;
a capacitor configured to charge from a voltage source;
a transistor configured to control current flowing through a semiconductor optical amplifier via a controlled discharge of the capacitor;
the semiconductor optical amplifier configured to amplify at least a temporal portion of the seed light in response to the current flowing through the semiconductor optical amplifier to emit an output pulse of light; and
a receiver configured to detect at least a portion of the output pulse of light scattered by a target object located at a distance from the system.
2 . The system of claim 1 , wherein the seed light is generated from a pulsed current source.
3 . The system of claim 1 , wherein the seed light is generated from a constant current source.
4 . The system of claim 1 , wherein the laser diode comprises a first p-type/n-type semiconductor diode that is electrically isolated from a second p-type/n-type semiconductor diode comprising the semiconductor optical amplifier.
5 . The system of claim 1 , wherein the semiconductor optical amplifier is further configured to be reverse-biased when it is not amplifying at least the temporal portion of the seed light.
6 . The system of claim 1 , wherein the semiconductor optical amplifier is further configured to be short-circuited when it is not amplifying at least the temporal portion of the seed light.
7 . The system of claim 1 , wherein the semiconductor optical amplifier includes an optical waveguide configured to receive the seed light.
8 . The system of claim 1 , wherein the transistor, the semiconductor optical amplifier, or both the transistor and the semiconductor optical amplifier are fabricated on a gallium nitride semiconductor base.
9 . The system of claim 1 , further comprising a shunt path coupled to the semiconductor optical amplifier and the transistor.
10 . The system of claim 9 , wherein the shunt path is configured to prevent the semiconductor optical amplifier and the transistor from being exposed to a voltage exceeding a specified safe operating voltage.
11 . The system of claim 1 , wherein the output pulse of light has a pulse signature that distinguishes the output pulse of light from one or more other pulses of light that can be detected by the receiver during a common detection period.
12 . The system of claim 11 , wherein the pulse signature is based at least in part on a pulse amplitude that depends at least in part on a peak voltage of the voltage source.
13 . The system of claim 11 , wherein the pulse signature is based at least in part on a pulse amplitude, rise time, or fall time that depends at least in part on a trigger signal shape received by the transistor.
14 . The system of claim 11 , wherein the pulse signature is based at least in part on a pulse amplitude, rise time, or fall time that depends at least in part on a pulsed current shape associated with the seed light.
15 . The system of claim 11 , wherein the pulse signature is based at least in part on a pulse amplitude, rise time, or fall time that depends at least in part on whether the capacitor is in a connected or disconnected configuration.
16 . The system of claim 1 , further comprising a scanner configured to scan an output beam across a field of regard of a lidar system.
17 . The system of claim 16 , wherein the system is included in the lidar system.
18 . The system of claim 1 , wherein the system is integrated into a vehicle as part of an autonomous-vehicle driving system.
19 . A method, comprising:
producing seed light using a laser diode;
charging a capacitor from a voltage source;
using a transistor to control current flowing through a semiconductor optical amplifier via a controlled discharge of the capacitor;
using the semiconductor optical amplifier to amplify at least a temporal portion of the seed light in response to the current flowing through the semiconductor optical amplifier to emit an output pulse of light; and
using a receiver to detect at least a portion of the output pulse of light scattered by a target object located at a distance from the receiver.
20 . A computer program product embodied in a non-transitory computer readable medium and comprising computer instructions for:
producing seed light using a laser diode;
charging a capacitor from a voltage source;
using a transistor to control current flowing through a semiconductor optical amplifier via a controlled discharge of the capacitor;
using the semiconductor optical amplifier to amplify at least a temporal portion of the seed light in response to the current flowing through the semiconductor optical amplifier to emit an output pulse of light; and
using a receiver to detect at least a portion of the output pulse of light scattered by a target object located at a distance from the receiver.