Transmitter and Receiver Circuits for a High-Speed Polymer Fiber-Based PAM-4 Communication Link

Area of Science:

• Electrical Engineering
• Optoelectronics
• Microwave Engineering

Background:

• High data rate communication systems are crucial for modern applications.
• Indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology offers excellent high-frequency performance.
• Polymer microwave fiber (PMF) presents a viable medium for high-frequency signal transmission.

Purpose of the Study:

• To design and fabricate a high data rate RF-DAC and a power detector (PD) for a communication link.
• To evaluate the performance of a communication link utilizing a PMF for signal transmission.
• To demonstrate high-speed data transmission with low bit error rate (BER) and high energy efficiency.

Main Methods:

• Fabrication of RF-DAC and PD using 250 nm InP DHBT technology.
• Integration of a pulse amplitude modulation (PAM) modulator and PD into a communication link with a 1-meter PMF.
• Measurement of the communication link's working frequency range, output power, bandwidth, and data transmission capabilities.

Main Results:

• The communication link operates in the 110–150 GHz frequency range.
• The PAM modulator exhibits a peak output power of 5 dBm and a -3 dB bandwidth of 43 GHz.
• The PMF link supports PAM-4 at 22 Gbps and PAM-2 at 30 Gbps with BER <10−12.
• Energy efficiency of the link is 4.1 pJ/bit (PAM-2) and 5.6 pJ/bit (PAM-4).

Conclusions:

• The developed InP DHBT-based RF-DAC and PD enable high-speed, energy-efficient communication over PMF.
• The compact Tx and Rx chips (0.83 mm2) are suitable for integration into various communication systems.
• This technology paves the way for next-generation terahertz communication systems.