InP photonic integrated externally injected gain switched optical frequency comb

Abstract

We report on an InP photonic integrated circuit for the generation of an externally injected gain switched optical frequency comb. The device is fully characterized and generates a comb with frequency spacing ranging from 6 to 10 GHz, good noise properties that include relative intensity noise of <-130 dB/Hz and linewidth of 1.5 MHz, and a high phase correlation between comb lines. These characteristics, in conjunction with the compactness and cost efficiency of the integrated device, demonstrate the quality of the resultant comb source for numerous applications.

Characterization and Direct Modulation of a Multi-Section PIC Suited for Short Reach Optical Communication Systems

“…These slots are used to control the longitudinal spectrum. Standard electron beam lithography is used in the fabrication of the slots to provide precise control of the slots' dimensions (width, depth) and location [16]. The total length of the device is ∼1.5 mm.…”

“…The left facet at the end of the slots region (reflector section) is high-reflection (HR)-coated. Both reflector sections of the two lasers are etched into the surface ridge waveguide, close to the active region, to provide internal reflections and enable a high SMSR (~50 dB) [16]. Furthermore, they provide improved control of the emission wavelength and the injection power inside the PIC.…”

Frequency Comb-Based WDM Transmission Systems Enabling Joint Signal Processing

“…Gain-switched laser diodes provide an interesting alternative as an integrated comb generator because they are very power efficient [37]. Reduction of the optical linewidth can be attained by injection locking to a master laser oscillator [38]. One additional challenge with this platform is scaling up the bandwidth and repetition rate to frequencies going significantly beyond 10 GHz.…”

Gain-switched semiconductor lasers with pulsed excitation and optical injection for dual-comb spectroscopy

“…In parallel to the search for innovative applications, many efforts have been devoted to develop alternatives to mode-locked OFCs, with the aim of providing tunable, cost-efficient and field-deployable comb generators [9][10][11]. Among these comb platforms, OFCs generated from semiconductor lasers by gain-switching (GS) have attracted considerable attention in recent years [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Besides benefiting from the usual advantages of semiconductor sources (high efficiency, low cost and small footprint), the comb generation by GS also offers low losses, flexible comb line spacing and, outstandingly, suitability for photonic integration [20].…”

“…Among these comb platforms, OFCs generated from semiconductor lasers by gain-switching (GS) have attracted considerable attention in recent years [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Besides benefiting from the usual advantages of semiconductor sources (high efficiency, low cost and small footprint), the comb generation by GS also offers low losses, flexible comb line spacing and, outstandingly, suitability for photonic integration [20]. OFCs based on GS have been applied in optical communications [21,22], sub-terahertz generation [23,27] and dual-comb spectroscopy (DCS) [16,24].…”