InP monolithically integrated coherent transmitter.

Area of Science:

• Photonics and Optical Communications
• Integrated Optics
• Semiconductor Devices

Background:

• Coherent optical communication systems require advanced transmitters for high-speed data transmission.
• Indium phosphide (InP) is a key material for fabricating high-performance photonic integrated circuits (PICs).

Purpose of the Study:

• To design, fabricate, and test a novel monolithically integrated coherent transmitter based on InP.
• To evaluate the performance of the integrated transmitter for polarization-division multiplexing quadrature phase-shift keying (PDM-QPSK) signals.

Main Methods:

• Design and fabrication of a PIC comprising a distributed Bragg reflector (DBR) laser and a Mach-Zehnder modulator (MZM) with tunable power splitters.
• Back-to-back coherent transmission experiments were conducted.

Main Results:

• The integrated transmitter demonstrated successful PDM-QPSK signal transmission at 10 Gbaud (40 Gb/s) using the on-chip DBR laser.
• Transmission rates of up to 32 Gbaud (128 Gb/s) were achieved when using an external low phase noise laser.

Conclusions:

• The developed InP monolithically integrated coherent transmitter shows promise for high-speed optical communication systems.
• The results highlight the potential of integrated photonics for advancing coherent transmission technologies.