A system for determining distance to a target object, the system comprising an optical transmitter having a laser to transmit an optical signal; an optical receiver to receive back a reflection of the optical signal from a target object; an electrical signal generator to provide an electrical reference signal to both the optical transmitter and the optical receiver; and a laser driver to directly modulate the laser with the electrical reference signal, the optical receiver including a local oscillator providing local oscillator light at a local oscillator frequency, a combiner to combine the reflection of the optical signal received by the receiver with the local oscillator light to output a coupled optical signal, an optical-electrical converter to convert the coupled optical signal into a first electrical signal, a rectifier to rectify the first electrical signal and thereby provide a first rectified electrical signal, and a signal processor to receive the first rectified electrical signal from the rectifier and the electrical reference signal from the electrical signal generator, and to calculate a distance traveled by the optical signal based on the first rectified electrical signal and the electrical reference signal, characterized in that the optical-electrical converter is implemented with a bandwidth that accounts for the bandwidth of the reference signal and of the optical signal, including variations resulting from frequency chirp, and in that the local oscillator frequency is merely selected and not controlled and acts as a wavelength selector relative to the bandwidth of the opto-electrical converter through selection of the local oscillator frequency to enable efficient reception of the reflected optical signal. an optical transmitter having a laser to transmit an optical signal; an optical receiver to receive back a reflection of the optical signal from a target object; an electrical signal generator to provide an electrical reference signal to both the optical transmitter and the optical receiver; and a laser driver to directly modulate the laser with the electrical reference signal, the optical receiver including a local oscillator providing local oscillator light at a local oscillator frequency, a combiner to combine the reflection of the optical signal received by the receiver with the local oscillator light to output a coupled optical signal, an optical-electrical converter to convert the coupled optical signal into a first electrical signal, a rectifier to rectify the first electrical signal and thereby provide a first rectified electrical signal, and a signal processor to receive the first rectified electrical signal from the rectifier and the electrical reference signal from the electrical signal generator, and to calculate a distance traveled by the optical signal based on the first rectified electrical signal and the electrical reference signal, characterized in that the optical-electrical converter is implemented with a bandwidth that accounts for the bandwidth of the reference signal and of the optical signal, including variations resulting from frequency chirp, and in that the local oscillator frequency is merely selected and not controlled and acts as a wavelength selector relative to the bandwidth of the opto-electrical converter through selection of the local oscillator frequency to enable efficient reception of the reflected optical signal.