Chip-based advanced modulation format transmitter

Abstract

In various embodiments, a monolithic integrated transmitter, comprising an on-chip laser source and a modulator structure capable of generating advanced modulation format signals based on amplitude and phase modulation are described.

What is claimed is: 
     
       1. A monolithically integrated optical transmitter comprising:
 at least one substrate; 
 a tunable laser resonator monolithically integrated with the substrate, the laser resonator configured to output radiation along an optical axis; 
 a first modulator monolithically integrated with the substrate, the first modulator including a first input waveguide configured to receive a first portion of the radiation output from the tunable laser resonator and modulate at least one of intensity or phase of the first portion of the radiation output from the tunable laser resonator; 
 a second modulator monolithically integrated with the substrate, the second modulator including a second input waveguide configured to receive a second portion of the radiation output from the tunable laser resonator and modulate at least one of intensity or phase of the second portion of the radiation output from the tunable laser resonator; and 
 an optical redirector integrated with the first or second input waveguide, the optical redirector configured to change the direction of propagation of optical radiation in the waveguide it is integrated with. 
 
     
     
       2. The optical transmitter of  claim 1 , further comprising an optical combiner monolithically integrated with the substrate and configured to combine optical signals output from the first modulator and the second modulator and generate a modulated optical signal, the optical combiner including a third input waveguide connected to the first modulator, a fourth input waveguide connected to the second modulator and at least one optical redirector integrated with the third or fourth input waveguide, the optical redirector configured to change the direction of propagation of optical radiation in the waveguide it is integrated with. 
     
     
       3. The optical transmitter of  claim 1 , wherein the substrate comprises at least one of Si, InP, InAlGaAs, InGaAsP, InGaP, GaAs or InGaAs. 
     
     
       4. The optical transmitter of  claim 1 , wherein the optical redirector has at least one reflective facet that is arranged at an angle with respect to the waveguide it is integrated with. 
     
     
       5. The optical transmitter of  claim 1 , wherein the optical redirector is configured to change the direction of propagation of optical radiation in the waveguide it is integrated with by an angle between approximately 90 degrees and approximately 180 degrees. 
     
     
       6. The optical transmitter of  claim 1 , wherein the optical redirector includes a dielectric. 
     
     
       7. The optical transmitter of  claim 1 , configured to generate a modulated optical signal with quadrature phase shift keying (QPSK) format or quadrature amplitude modulation (QAM) format. 
     
     
       8. The optical transmitter of  claim 1 , wherein at least one of the first and second modulators comprises a dual nested Mach-Zehnder modulator. 
     
     
       9. The optical transmitter of  claim 1 , wherein each of the first and the second modulators comprises at least one electrode. 
     
     
       10. The optical transmitter of  claim 9 , wherein each of the first and the second optical modulators comprises at least four electrodes. 
     
     
       11. The optical transmitter of  claim 1 , further comprising one or more monitor electrodes configured to monitor power of the modulated optical signal at the output of the first or second optical modulator. 
     
     
       12. The optical transmitter of  claim 11 , further comprising a feedback circuit configured to provide an input electrical signal to the first or second optical modulators based on an output of the one or more monitor electrodes. 
     
     
       13. The optical transmitter of  claim 1 , wherein the tunable laser resonator comprises:
 a first optical path including a first reflector; 
 a second optical path including a second reflector; and 
 an active region comprising an active material, the active region optically connected to the first and second optical paths. 
 
     
     
       14. The optical transmitter of  claim 13 , further comprising at least one optical redirector configured to optically connect the active region to the first and second optical paths. 
     
     
       15. An optical transmitter comprising:
 a substrate; 
 an optical source comprising:
 an active region comprising an active material, the active region including a first side and a second side opposite the first side; 
 a first optical path including a first reflector, the first optical path connected to the first side of the active region; 
 a second optical path including a second reflector, the second optical path connected to the second side of the active region; and 
 at least one optical redirector disposed in the first optical path or the second optical; 
 
 a first modulator monolithically integrated with the substrate, the first modulator including a first input waveguide configured to receive a first portion of the radiation output from the tunable laser resonator along the first optical path, the first modulator configured to modulate at least one of intensity or phase of the first portion of the radiation output from the tunable laser resonator; and 
 a second modulator monolithically integrated with the substrate, the second modulator including a second input waveguide configured to receive a second portion of the radiation output from the tunable laser resonator along the second optical path, the second modulator configured to modulate at least one of intensity or phase of the second portion of the radiation output from the tunable laser resonator. 
 
     
     
       16. The optical transmitter of  claim 15 , wherein the optical redirector is configured to change the direction of propagation of optical radiation in the first or second optical paths by an angle between about 90 degrees and about 180 degrees. 
     
     
       17. The optical transmitter of  claim 15 , wherein the optical redirector comprises a reflective facet that is arranged at an angle with respect to the first or second optical path. 
     
     
       18. The optical transmitter of  claim 15 , wherein the optical redirector includes a dielectric. 
     
     
       19. The optical transmitter of  claim 15 , further comprising an optical combiner monolithically integrated with the substrate, the optical combiner configured to combine optical signals output from the first modulator and the second modulator and generate a modulated optical signal. 
     
     
       20. The optical transmitter of  claim 19 , wherein the optical combiner includes a third input waveguide connected to the first modulator, a fourth input waveguide connected to the second modulator and at least one optical redirector integrated with the third or fourth input waveguide, the optical redirector configured to change the direction of propagation of optical radiation in the waveguide it is integrated with.