Hyun-chul Park

Highly integrated optical heterodyne phase-locked loop with phase/frequency detection.

A highly-integrated optical phase-locked loop with a phase/frequency detector and a single-sideband mixer (SSBM) has been proposed and demonstrated for the first time. A photonic integrated circuit (PIC) has been designed, fabricated and tested, together with an electronic IC (EIC). The PIC integrates a widely-tunable sampled-grating distributed-Bragg-reflector laser, an optical 90 degree hybrid and four high-speed photodetectors on the InGaAsP/InP platform. The EIC adds a single-sideband mixer, and a digital phase/frequency detector, to provide single-sideband heterodyne locking from -9 GHz to 7.5 GHz. The loop bandwith is 400 MHz.

Monolithic Integration of a High-Speed Widely Tunable Optical Coherent Receiver

In this letter, a monolithically integrated widely tunable optical receiver is demonstrated. A sampled-grating DBR (SG-DBR) laser, an optical 90-degree hybrid, four high-speed uni-travelling-carrier photodetectors and microstrip transmission lines are integrated on a single InGaAsP/InP chip. A 42-nm tuning range and a 35-GHz detector bandwidth are achieved. Experiments show real-time reception of 40 Gb/s BPSK data.

40Gbit/s coherent optical receiver using a Costas loop

A highly integrated 40 Gbit/s coherent optical receiver is reported using a Costas loop as a homodyne optical phase locked loop (OPLL). A photonic IC, an electrical IC, and a hybrid loop filter are characterized, and the feedback loop system is fully analyzed to build a stable homodyne OPLL. All components are integrated on a single substrate within the compact size of 10 × 10mm(2), and a 1.1 GHz loop bandwidth and a 120 psloop delay are achieved. The binary phase-shift keying receiver exhibits error-free (BER<10(-12)) up to 35 Gbit/s and BER<10(-7) for 40 Gbit/s with no latency, and consumes less than 3 W power.

An Integrated 40 Gbit/s Optical Costas Receiver

In this paper, a highly-integrated widely-tunable optical homodyne receiver is reported with 40 Gbaud/s data rate. By using photonic and electronic integration, the receiver is realized within a size of 10 × 10 mm2, and the system is very robust and resistive to environmental changes. An integrated photonic coherent receiver circuit is demonstrated with 35 GHz photodetector bandwidth, and the integrated local oscillator (LO) laser covers a 40 nm range. The electronic IC (EIC) has a working frequency up to 50 GHz. The feedback loop is carefully analyzed and designed, and the experimental results show > 1.1 GHz loop bandwidth, which matches the design. The hold-in range is measured to be > 15 GHz. The phase noise of the transmitting laser has been cloned to the LO laser quite well, and both the linewidth measurement and phase noise measurement show no observable cross talk between binary phase shift keying (BPSK) data and the optical phase-locked loop (OPLL). Error free ( bit error rate <; 10-12) is achieved up to 35 Gbit/s. The system consumes 3 Watts of power.

Millimeter-Wave Series Power Combining Using Sub-Quarter-Wavelength Baluns

We present a new millimeter-wave power-combining technique using transmission-line baluns which both connect transistor outputs in series and inductively tune the transistor output capacitances. The baluns are much shorter than a quarter-wavelength (λ/4), hence are more compact and have less insertion loss than a λ/4 balun. We introduce one topology providing an even number of series connections, including 2:1 and 4:1, and a second topology providing either an even or odd number of series connections. We then analyze segmented transformer power-combiners as a set of multi-conductor transmission-lines, and explore the relationship between transformer and transmission-line balun power-combiners. We demonstrate the technique with 2:1 and 4:1 series-connected designs implemented in a 0.25 μm InP HBT process. At 86 GHz, a single-stage power amplifier (PA) using the 2:1 baluns exhibits 30.4% peak PAE, 20.37 dBm output power (Pout) and 23 GHz 3-dB bandwidth from a 448 × 816 μm 2 die. A two-stage PA using the 2:1 baluns exhibits 30.2% PAE, and 23.14 dBm Pout from an 824 × 816 μm 2 die. At 81 GHz, a two-stage PA with 4:1 series output power-combining exhibits 23.4% PAE, and 26.7 dBm (470 mW) Pout from a 1,080 × 980 μm 2 die.

30% PAE W-Band InP Power Amplifiers Using Sub-Quarter-Wavelength Baluns for Series-Connected Power-Combining

We present high-efficiency W-band power amplifier (PA) ICs with a new series-connected power combining technique using sub-quarter-wavelength transmission- line baluns. The PAs are implemented in a 0.25μm InP HBT process. At 86GHz, a single-stage PA exhibits 30.4% peak PAE, 20.37dBm Pout and 23GHz 3dB bandwidth. A two-stage PA exhibits 30.2% PAE, and 23.14dBm Pout. These values of PAE represent a 1.2:1 improvement in the state-of-the-art for E- and W- band PAs having similar RF output powers.

A 1–20-GHz All-Digital InP HBT Optical Wavelength Synthesis IC

An integrated circuit (IC) for heterodyne optical phase locking in a 1-20-GHz offset range is hereby reported. The IC, implemented in a 500-nm InP HBT process, contains an emitter coupled logic digital single-sideband mixer to provide phase locking at a ± 20-GHz offset frequency, and a wideband phase-frequency detector designed to provide loop acquisition up to ±40-GHz initial frequency offset. The all-digital IC design has phase-frequency detection gain independent of IC process parameters or optical signal levels, and provides a wide offset locking range. A 100-ps delay decreases the overall loop delay, making wideband loop filter design possible. In addition, a medium-scale high-frequency logic design methodology is presented and fully discussed.

A 1–20 GHz InP HBT phase-lock-loop IC for optical wavelength synthesis

We report a PLL IC for locking, at a controlled frequency offset between 1 and 20 GHz, the optical phase and optical frequency of a slave semiconductor laser to that of a reference semiconductor laser. The IC, implemented in a 500 nm InP HBT process, contains an ECL digital single-sideband mixer to provide phase-locking at a +/− 20 GHz offset frequency, and also contains a wideband phase-frequency detector to provide loop acquisition given up to +/−40 GHz initial frequency offset.

High efficiency W-band power amplifiers using ring-shaped sub-quarter-wavelength power combining technique

We present W-band power amplifiers which are designed using the sub-quarter-wavelength transmission line balun in a ring-shaped configuration and fabricated in a 0.25 μm InP DHBT technology. Operating at 86GHz, a single-stage PA exhibits 20.86dBm saturated output power with 10.2dB peak power gain, a recored PAE of 35% and a record 3-dB bandwidth of 33GHz. A two-stage PA exhibits 22.75dBm saturated output power with 20.4dB peak power gain, a PAE of 32.8% and a 3-dB bandwidth of 16GHz.

Highly-Stable Integrated InGaAsP/InP Mode-Locked Laser and Optical Phase-Locked Loop

We demonstrate an integrated InGaAsP/InP mode-locked laser that is stabilized with an optical phase-locked loop (OPLL). Using the OPLL, a single comb line is locked to a reference oscillator (a 200 Hz linewidth Brillouin laser). The comb linewidth is reduced from 100 MHz (unlocked) to <; 550 Hz (locked) using the OPLL. The rms phase error between the comb and reference laser is 20°. The linewidth of the adjacent comb lines is <; 1 kHz, and the comb spans 430 GHz.