Optical generation of a megahertz-linewidth microwave signal using semiconductor lasers and a discriminator-aided phase-locked loop

A discriminator-aided optical phase-locked loop (OPLL) with significantly enhanced frequency acquisition capability is presented. Its pull-in range is measured to be 300 MHz and can be easily extended further. Two grating-tuned external-cavity semiconductor lasers (ECSLs) were realized with more than 30-dB side-mode suppression ratio. These two lasers were allowed to beat on a fast detector and were offset phase locked. The generated microwave signal was found to be a replica of the reference RF signal close to the carrier, The noise level was measured to be -70 dBc/Hz close to the carrier and less than -100 dBc/Hz at 4 MHz away and beyond from the carrier. The total phase variance is 0.11 rad/sup 2/ over a 500-MHz bandwidth. The linewidth full width at half maximum (FWHM) of the locked signal was directly measured to be of order 1 mHz.

[1]  H. Taylor,et al.  35 GHz microwave signal generation with an injection-locked laser diode , 1985 .

[2]  Mario Dagenais,et al.  Tunable external cavity semiconductor lasers with a 50 dB side mode suppression ratio , 1997, CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics.

[3]  A. Mooradian,et al.  Linewidth and offset frequency locking of external cavity GaAlAs lasers , 1989 .

[4]  J. Zayhowski,et al.  Phase locking of 1.32-microm microchip lasers through the use of pump-diode modulation. , 1992, Optics letters.

[5]  A new automatic frequency-control method for fast frequency switching of a coherent optical receiver , 1996, IEEE Photonics Technology Letters.

[6]  R. S. Raven,et al.  Requirements on master oscillators for coherent radar , 1966 .

[7]  C. R. Lima,et al.  Optical generation of millimeter-wave signals for fiber-radio systems using a dual-mode DFB semiconductor laser , 1995 .

[8]  H. Taylor,et al.  Microwave signal generation with injection-locked laser diodes , 1983 .

[9]  M Dagenais,et al.  Tunable external cavity diode laser that incorporates a polarization half-wave plate. , 1992, Applied optics.

[10]  L. H. Enloe,et al.  Laser phase-locked loop , 1965 .

[11]  Alwyn J. Seeds,et al.  Delay, linewidth and bandwidth limitations in optical phase-locked loop design , 1990 .

[12]  U. Gliese,et al.  A wideband heterodyne optical phase-locked loop for generation of 3-18 GHz microwave carriers , 1992, IEEE Photonics Technology Letters.

[13]  C.-H. Shin,et al.  A 134 MHz bandwidth homodyne optical phase-locked-loop of semiconductor laser diodes , 1991, IEEE Photonics Technology Letters.

[14]  R. C. Steele,et al.  Optical phase-locked loop using semiconductor laser diodes , 1983 .

[15]  Timothy Day,et al.  Widely tunable external cavity diode lasers , 1995, Photonics West.

[16]  C.-H. Shin,et al.  Heterodyne optical phase-locked loop by confocal Fabry-Periot cavity coupled AlGaAs lasers , 1990, IEEE Photonics Technology Letters.

[17]  Rolf Dr Heidemann,et al.  Dispersion effects in optical millimeter-wave systems using self-heterodyne method for transport and generation , 1995 .

[18]  G. J. Simonis,et al.  Optical generation, distribution, and control of microwaves using laser heterodyne , 1990 .

[19]  D. B. Leeson,et al.  Short-term stability for a Doppler radar: Requirements, measurements, and techniques , 1965 .

[20]  U. Gliese,et al.  Chromatic dispersion in fiber-optic microwave and millimeter-wave links , 1996 .

[21]  Lew Goldberg,et al.  Generation and control of microwave signals by optical techniques , 1992 .

[22]  Mario Dagenais,et al.  6-34 GHz offset phase-locking of Nd:YAG 1319 nm nonplanar ring lasers , 1989 .

[23]  A. Seeds,et al.  Fast heterodyne optical phase-lock loop using double quantum well laser diodes , 1992 .

[24]  U. Gliese,et al.  Laser linewidth requirements and improvements for coherent optical beam forming networks in satellites , 1991 .