High data rate long reach transceiver using wavelength multiplexed architecture
View Patent ↗Optical telecommunication modules including transmitters and receivers and methods of using same. In some embodiments the transmitters include a chip having an array of lasers and a combiner for combining light from the lasers for transmission over an optical fiber. Preferably the lasers have widely spaced wavelengths. The chip may be semi-cooled in some embodiments. A dither signal may be provided to one laser for use by a receiver in tracking temperature of the laser for improved receiver performance. In some embodiments a plurality of EMLs are used instead of a greater number of plurality of DFBs for transmission.
1. A photonic transmitter integrated circuit, comprising:
a semiconductor chip with front and rear facets with associated anti-reflection properties; a substrate;
an array of distributed feedback (DFB) lasers formed on the substrate, each laser in the array of lasers having a grating with a phase shift position offset to the front to increase front facet power, its own bond pad for receiving a data signal, a laser cavity length no greater than 250 microns and emitting light at different wavelengths, with a wavelength spacing between adjacent laser wavelengths greater than 5 nm; and
an arrayed waveguide grating formed on the substrate to receive light emitted by lasers of the array of lasers, the arrayed waveguide grating configured to combine light emitted by the array of lasers; and
a temperature controller designed to maintain the array of lasers in a semi-cooled state such that the wavelength range of the lasers in the array does not exceed the wavelength spacing but allowed to drift over a temperature range that would exceed a wavelength spacing less than 1.6 nm.
2. The photonic transmitter integrated circuit of claim 1 , further comprising an integrated photo diode on the substrate on a side of the DFB lasers opposite the interferometric combiner.
3. The photonic transmitter integrated circuit of claim 2 wherein the integrated photo diode is electronically isolated from the DFB lasers.
4. The photonic transmitter integrated circuit of claim 3 wherein the integrated photo diode is reverse biased.
5. The photonic transmitter integrated circuit of claim 1 wherein the temperature controller is configured to adjust the temperature if the temperature of the circuit migrates outside of a temperature window of about 40 C.