95 GHz millimeter wave signal generation using an arrayed waveguide grating dual wavelength semiconductor laser

Abstract

We report the generation of a 95 GHz carrier frequency by optical heterodyning of two wavelengths from adjacent channels from an arrayed waveguide grating-based multiwavelength laser. The extended cavity structure of the device provides low phase noise and narrow optical linewidth, further enhanced by the intracavity filter effect of the arrayed waveguide grating. We demonstrate that the generated RF beat note, at 95 GHz, has a -3 dB linewidth of 250 kHz. To the best of our knowledge, this is the narrowest RF linewidth generated from a free-running dual-wavelength semiconductor laser. The device is realized as a photonic integrated circuit using active-passive integration technology, and fabricated on a multiproject wafer run, constituting a novel approach for a compact, low-cost dual-wavelength heterodyne source.

Recent Progress and Future Prospect of Photonics-Enabled Terahertz Communications Research

“…The wavelength spacing among adjacent channels is determined by the AWG channel spacin, Δλ, typically around 0.8 nm (100 GHz). While the drawback of this approach is that it is difficult to tune the generated wavelengths, these are extremely narrow producing highly stable frequencies [63].…”

TeraHertz Photonics for Wireless Communications

“…Fig. 5 presents one realization of this AWG laser approach, produced using an InP technology multi-project wafer run [12], [14], [15]. The structure shows four AWG channels with 1 mm long SOAs in each channel, providing the laser gain medium.…”

“…Although the emission of the wavelengths are fixed by the channel pass-bands of the AWG, this structure shows very narrow optical mode linewidths (<200 kHz) without the need for any additional phase noise reduction scheme. This structure was demonstrated to generate a RF carrier at 95 GHz with a 250 kHz linewidth, which is the narrowest RF linewidth from a free-running, dualwavelength semiconductor laser [14], [15]. …”

Frequency stability of a dual wavelength quantum cascade laser

“…Simpler laser systems simultaneously emitting at only two close wavelengths are attractive for a number of applications, such as the transmission of radio frequency (RF) signals over optical fibers [9,10] or in free space [11], light detection and ranging (LIDAR) [12], or RF generation [13,14]. Their interest lies in the fact that they simultaneously provide an optical (≈100 THz) and an RF signals (≈10 GHz).…”