A reconfigurable photonic integrated transmitter, enabling dynamic resource allocation in the metro-access network, is proposed. The device consists of a multicarrier sliceable bandwidth variable transmitter (MC-SBVT) realized in indium phosphide and a silicon-nitride-based optical cross-connect (OXC). The proposed architecture delivers full flexibility in terms of the choice of data format/bandwidth, channel spacing, and wavelength assignment. The functional design of the MC-SBVT and OXC as well as their practical realization are discussed. Preliminary characterization results of the photonic-integrated-circuit-based MC-SBVT, demonstrating the reconfigurability of the device, are also presented.

The application of two gain switched optical frequency combs (OFCs) in dual comb gas phase spectroscopy is demonstrated. We report on the stability analysis of the wavelength and power of individual comb lines of the two OFCs. The examination reveals that a maximum wavelength fluctuation of <2.5 pm and a maximum peak power fluctuation of ?0.3 dB is achievable for the OFCs. The radio frequency (RF) beat tone spectrum shows the standard deviation of the peak power of an individual beat tone from the mean is as low as ?0.14 dB with negligible frequency fluctuations. In a proof-of-principle experiment the dual comb system is applied to the detection of hydrogen sulphide (H2S) with a detection sensitivity of (740 ± 160) ppmv, demonstrating its excellent frequency and power stability. The dual OFCs can in principle be monolithically integrated and thus enable the development of compact, cost-efficient dual comb devices, for the detection of multiple trace gas species or isotopologues.

The authors demonstrate and characterise a monolithically integrated optical frequency comb (OFC) source, based on mutually injection-locked gain-switched lasers (MIL-GSL). The photonic integrated circuit (PIC) consists of two single mode slave lasers and a wavelength tunable single mode master laser. The working principle of this PIC relies on the simultaneous injection-locking of the two gain switched slave lasers, with partially overlapping spectra, with a common master laser. This results in the generation of a MIL-GSL expanded comb, exhibiting a spectral width of 256.25 GHz, low phase and amplitude noise, excellent phase correlation between the comb lines, and flexibility in terms of comb line separation. The PIC-based implementation offers additional advantage of lower complexity, small footprint, and reduced energy consumption.