title: Monolithically integrated heterodyne optical phase-lock loop with RF XOR phase detector.
abstract: We present results for an heterodyne optical phase-lock loop (OPLL), monolithically integrated on InP with external phase detector and loop filter, which phase locks the integrated laser to an external source, for offset frequencies tuneable between 0.6 GHz and 6.1 GHz. The integrated semiconductor laser emits at 1553 nm with 1.1 MHz linewidth, while the external laser has a linewidth less than 150 kHz. To achieve high quality phase locking with lasers of these linewidths, the loop delay has been made less than 1.8 ns. Monolithic integration reduces the optical path delay between the laser and photodiode to less than 20 ps. The electronic part of the OPLL was implemented using a custom-designed feedback circuit with a propagation delay of ~1 ns and an open-loop bandwidth greater than 1 GHz. The heterodyne signal between the locked slave laser and master laser has phase noise below -90 dBc/Hz for frequency offsets greater than 20 kHz and a phase error variance in 10 GHz bandwidth of 0.04 rad2.
authors: Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK.
authors: Robert J
authors: RJ
authors: Steed
authors: Francesca
authors: F
authors: Pozzi
authors: Martyn J
authors: MJ
authors: Fice
authors: Cyril C
authors: CC
authors: Renaud
authors: David C
authors: DC
authors: Rogers
authors: Ian F
authors: IF
authors: Lealman
authors: David G
authors: DG
authors: Moodie
authors: Paul J
authors: PJ
authors: Cannard
authors: Colm
authors: C
authors: Lynch
authors: Lilianne
authors: L
authors: Johnston
authors: Michael J
authors: MJ
authors: Robertson
authors: Richard
authors: R
authors: Cronin
authors: Leon
authors: L
authors: Pavlovic
authors: Luka
authors: L
authors: Naglic
authors: Matjaz
authors: M
authors: Vidmar
authors: Alwyn J
authors: AJ
authors: Seeds