Millimeter-wave radio-over-fiber system using optical phase modulation and photonic downconversion for uplink fronthaul transmission.

This Letter proposes a high-performance radio-over-fiber (RoF) system for high-speed and high-fidelity analog waveform transmission of radio signals in the millimeter-wave band in the uplink direction. At the antenna site, the system utilizes a newly fabricated low half-wave voltage broadband phase modulator to convert a millimeter-wave radio signal into an optical signal. At the receiver, by using photonic downconversion and optical filtering technology, a simple direct detection and downconversion of the signal to the microwave band can be achieved simultaneously.

High-gain, wide-dynamic-range parametric interaction in Mg-doped LiNbO3 quasi-phase-matched adhered ridge waveguide.

With recent developments and optimizations for quasi-phase-matched adhered ridge waveguide (QPM-ARW), outstanding performances containing efficient amplification were demonstrated by difference frequency generation (DFG) and optical parametric amplification (OPA). A maximum channel conversion efficiency of +7.6 dB (570%) was achieved in a telecommunication band using a 50 mm-long device, when coupling with 160 mW pump.

Reconfigurable multilevel transmitter using monolithically integrated quad Mach-Zehnder IQ modulator for optical 16-QAM and 8-PSK generation.

We propose and demonstrate a reconfigurable multilevel transmitter using a monolithically-integrated quad Mach-Zehnder in-phase/quadrature (QMZ-IQ) modulator with binary driving electronics. Different from previous parallel-integrated quadrature amplitude modulation (QAM) transmitter solutions, only one electrode is required to adjust the relative phase offset among embedded sub-Mach-Zehnder modulators in the proposed IQ superstructure. By feeding different RF driving electronics and operating the integrated modulator as different bias conditions, different advanced multilevel modulation formats, such as QAM and 8-ary phase-shift keying (8-PSK), could be synthesized.

Optical minimum-shift-keying transmitter based on a monolithically integrated quad Mach-Zehnder in-phase and quadrature modulator.

We propose and demonstrate an optical minimum-shift-keying (MSK) transmitter using a single-quad Mach-Zehnder (MZ) in-phase and quadrature modulator, where four sub-Mach-Zehnder modulators are monolithically integrated on a main MZ superstructure. Using the proposed transmitter, a MSK signal at bit rate of B could be successfully generated by orthogonally superposing two low-speed (B/2) carrier-suppressed return-to-zero differential phase-shift-keying streams with a relative time offset, 1/B. MSK signals at bit rate of 20 and 80 Gbits/s were successfully generated using the proposed MSK transmitter.

320 Gbps to 10 GHz sub-clock recovery using a PPLN-based opto-electronic phase-locked loop.

We present successful extraction of a 10 GHz clock from single-wavelength 160 and 320 Gbps OTDM data streams, using an opto-electronic phase-locked loop based on three-wave mixing in periodically-poled lithium niobate as a phase comparator.

High-speed optical DQPSK and FSK modulation using integrated Mach-Zehnder interferometers.

We investigated an integrated optical modulator consisting of two Mach-Zehnder interferometers. The modulator can generate optical signals in various types of modulation formats, which have advantages for long-haul transmission, optical labeling, etc. By using a fabricated versatile optical modulator having traveling-wave electrodes designed for high-speed signals, we demonstrated generation of optical 40Gb/s frequency-shift-keying signals, which can be demodulated by an optical filter.