Patent ID: 8971362
Filing Date: 2015-03-03
Classification: H01S

Abstract:
1. A monolithic transmitter photonic integrated circuit (TxPIC) chip comprising: a plurality of semiconductor lasers integrated on said TXPIC chip, the plurality of semiconductor lasers being arranged in an array, each semiconductor laser of the plurality of semiconductor lasers having a front facet supplying a corresponding one of a plurality of optical outputs, each of the plurality of optical outputs having a corresponding one of a plurality of wavelengths; a plurality of modulators, each of which receiving a corresponding one of the plurality of optical outputs and supplying a corresponding one of a plurality of transmitter signal channels; an optical combiner integrated on said chip that is optically coupled to receive said plurality of transmitter signal channels from said plurality of modulators and combine the plurality of transmitter signal channels into a combined channel output signal on an optical waveguide output from said chip; a plurality of first photodetectors, each of which corresponding to a respective semiconductor laser of the plurality of semiconductor lasers, and optically coupled to receive an output from a back facet of a corresponding laser of the plurality of semiconductor lasers; a second photodetector optically coupled to receive a portion of said combined channel output signal; a frequency tone source that modulates each semiconductor laser of said plurality of semiconductor lasers with a respective one of a plurality of frequency tones as superimposed on a respective one of a plurality of bias currents applied to a respective semiconductor laser of the plurality of semiconductor lasers; an amplifier coupled to one of the plurality of first photodetectors; a first circuit that filters an AC component of an output of the amplifier; a second circuit that filters a DC component of the output of the amplifier; and a signal processing circuit that receives outputs of the first and second circuits and supplies an output to the frequency tone source, the frequency tone source adjusting a tone depth of one of the frequency tones based on the output of the signal processing circuit.