Optical generation of millimeter-wave signals for fiber-radio systems using a dual-mode DFB semiconductor laser

Abstract

This paper presents a new approach to the optical generation of millimeter-wave signals using a dual-mode multisection distributed feedback semiconductor laser. This simple device is capable of generating high power signals between 40 and 60 GHz with extremely high spectral purity and stability. The two optical modes produced by this laser are heterodyned on an ultrafast photodiode to give a beat signal at the mode difference frequency. The phase noise of the beat signal is greatly reduced by phase-locking the modes using an electrical drive signal applied to the laser at a subharmonic of the beat frequency. Millimeter-wave signals are obtained with a linewidth of less than 10 Hz, a phase noise of less than -85 dBc/Hz at 100 kHz offset, and a locking range of about 500 MHz. Millimeter-wave fiber-radio systems are seen as a major application area for these new compact optical sources.

A comparative test of Brillouin amplification and erbium-doped fiber amplification for the generation of millimeter waves with low phase noise properties

“…In [7], the 60-GHz region phase noise of 59 and 85 dBc/Hz at 10 and 100 kHz, respectively, offset from the carrier were measured. A millimeter-wave generation of 42 GHz was shown in [8] where a measurement of 80 dBc/Hz at 10-kHz offset was verified. By using the method of PM-IM conversion in chirped fiber gratings, a phase noise of 87 dBc/Hz at 10-kHz offset at a frequency of 28 GHz were measured [9].…”

Transmission of Light Intensity Modulation Signals in Analog Fiber-Optic Links

“…The primary reason for the linear distortions is the group velocity dispersion of electromagnetic waves in the fiber. Some compensation techniques of such distortions are discussed in [5][6][7][8].…”

Photonic Components for Analog Fiber Links

“…Optical heterodyning also has the advantage over other generation techniques of generating high RF power, though optical sources with narrow linewidth or feedback loops are required during operation [13]. The following section includes descriptions of the most common techniques to generate microwave signals using the optical heterodyning method, including optical injection locking (OIL) of laser diodes [14], external modulation technique [15], dual-mode semiconductor laser sources [16] as well as using the optical phase locked loop (OPLL) configuration [17].…”