Mu-Chieh Lo

Mode-locked laser with pulse interleavers in a monolithic photonic integrated circuit for millimeter wave and terahertz carrier generation

This Letter presents a photonics-based millimeter wave and terahertz frequency synthesizer using a monolithic InP photonic integrated circuit composed of a mode-locked laser (MLL) and two pulse interleaver stages to multiply the repetition rate frequency. The MLL is a multiple colliding pulse MLL producing an 80 GHz repetition rate pulse train. Through two consecutive monolithic pulse interleaver structures, each doubling the repetition rate, we demonstrate the achievement of 160 and 320 GHz. The fabrication was done on a multi-project wafer run of a generic InP photonic technology platform.

A monolithic optical heterodyne source based on dual DFB lasers using an InP generic foundry platform

A photonic integrated circuit developed in a generic foundry platform for continuously tunable microwave generation is presented. On this chip, two single-wavelength DFB laser diodes generate a two-tone emission through one optical waveguide coupler as combiner. The two-tone emission spectrum with >50-dB suppression ratio exhibits a continuous wavelength offset tunability up to ~4.3 nm, corresponding to 0.55-THz. With an external photodiode, a RF beat note at 10 GHz is experimentally demonstrated..

Monolithic symmetric multiple colliding pulse mode-locked laser by using on-chip reflectors

In this paper, we present a mode-locked laser photonic integrated chip developed within a multi-project wafer run at an InP-based generic foundry. The 1.66-mm-long Fabry-Perot cavity is formed with two on-chip multimode interence reflectors in which four gain sections and three saturable absorbers equally divide the cavity in four. The fourth harmonic colliding pulse configuration supports pulse train generation of 100 GHz, corresponding to 0.8-nm mode spacing. Autocorrelation traces exhibit the ultrafast pulse widths as short as 0.5 ps. Terahertz dual-mode spectra are presented as well.

On-chip selectable-frequency comb generation by passive harmonic mode locking

A monolithic integrated 2.8-mm colliding-pulse mode-locked laser is demonstrated to emit optical combs with switchable mode spacing for millimeter-wave generation. By selecting the DC-bias condition, the laser is forced to operate in harmonic mode locking regimes. Optical frequency combs with mode spacing of 2nd (30 GHz), 3rd (45 GHz), 4th (60 GHz) and 6th (90 GHz) harmonics are presented. The autocorrelation trace of 2nd harmonic exhibits a 1.03-ps pulsewidth. The beat note of 4th harmonic has an RF linewidth of 520 kHz.

Mode-locked photonic integrated circuits for millimeter and terahertz wave wireless communications

We present a 160 GHz pulsed source, based on an on-chip repetition rate multiplier scheme to double the repetition rate of an 80 GHz multiple pulse colliding mode-locked (mCPM) laser. For the first time to our knowledge, we demonstrate the monolithic integration of the mCPM laser and the pulse rate multiplier structures, using a generic foundry approach. From a 20 GHz fundamental repetition rate we achieve a ×4 increase, up to 160 GHz. The FWHM pulse width of 160 GHz pulse train is 0.979 ps.