We propose and experimentally demonstrate an O-band multi-wavelength high-power DFB laser array for optical I/O technology. The proposed DFB laser array operates with 400-GHz wavelength spacing, which meets the CW-WDM MSA specifications. The reconstruction equivalent chirp technology is used to precisely control the grating phase and introduce the equivalent $\pi $ phaseshift in the laser cavity. The AR and HR films are coated on the front and rear facets to increase the output power. The equivalent $\pi $ phaseshift is placed near the HR film facet to improve the single longitudinal mode yield. The optical spectra were measured at a bias current of 150 mA, with the wavelength deviations of below 1.958 GHz, and the SMSRs of above 55 dB. Statistical analysis shows 94.8% of SMSRs are above 40 dB, and 90.0% of the wavelength spacings deviate from the designed value within ±12.5%. The laser output power is over 100 mW at the bias current of above 370 mA. The far-field divergence angle of the laser was measured to be $25.5^{\circ } \times 29.9^{\circ }$ and the measured Lorentzian linewidth is 1.68 MHz at the bias current of 150 mA. The proposed O-band multi-wavelength DFB laser array shows uniform wavelength spacing, high output power, and good single longitudinal mode stability, which is promising to be used as the multiple wavelength laser source in the optical I/O technology.

A large-capacity ultra-weak fiber Bragg grating (UW-FBG) array interrogation system is proposed and implemented. The system utilizes time- and wavelength-division multiplexing methods, based on a large-range tunable laser source (TLS) with fast tuning capability. The TLS consists of a distributed feedback multi-wavelength laser array (DFB-MLA) with a wavelength tuning range of 40 nm, which is realized using the reconstruction-equivalent-chirp (REC) technique. An external SOA modulator is used to modulate the output light from the TLS into nanosecond pulsed light. We establish an experimental system and successfully achieve 50 UW-FBGs interrogation. We perform temperature, strain, and vibration sensing experiments with a interrogation linearity of above 0.9995 and an error of less than 4 pm. Theoretically, the system is estimated to have an interrogation capability of more than 10,000 UW-FBGs, and the minimum spacing of adjacent UW-FBGs is 0.4 m. This research has made significant advancements in the multiplexing capability and spatial resolution of the UW-FBG array interrogation technology, offering important application potential in fields such as battery pack, structural health monitoring, and aerospace.

In the field of biomedicine, the non-destructive and label-free detection of individual living cells has been long pursued. We propose a tapered fiber optic biosensor (TFOB), and perform theoretical and simulation analyses of the optical intensity distribution of the fiber tip, which gradually becomes thinner to expose the evanescent field around it. The fiber tip becomes a highly sensitive sensing element that acts as a transduction mechanism for the evanescent field. It translates the intensity change of the evanescent field around the tapered fiber into changes in output power. Experimental results show that the developed TFOB can detect vibration signals with amplitudes as low as 3 nm and achieve nondestructive, label-free measurements of respiratory vibrations of pasta yeast cells. Results show the periodic motion of yeast cells in the range of 300–550 Hz. Meanwhile, inactivated yeast cells have no characteristic frequencies evident in the spectrum. This nanoscale fiber optic sensor offers potential technical support for cell activity detection and pathological analysis.

A novel fiber Bragg grating (FBG) sensing system with a core laser source comprising a high-density integrated distributed feedback (DFB) laser array based on the reconstruction-equivalent-chirp (REC) technique is presented and demonstrated. This study proposes a fast and wideband wavelength-swept laser (WSL) based on a DFB laser array. 24 lasers are monolithically integrated with an 8 × 3 matrix structure with a wavelength spacing of 2.1 nm. The REC technique is used to simplify the grating fabrication and enhance the precise control of the wavelength spacing. Furthermore, a high-speed FBG sensing system using field-programmable gate arrays (FPGA) is proposed and demonstrated, achieving stable high-speed sweeping with a wavelength coverage of 50.4 nm and a sweeping frequency of up to 5.85 kHz without mode hopping. The FBG sensing system has a solid-state design without moving parts, allowing real-time, high-speed, and stable monitoring of temperature, pressure, strain, and displacement. It maintains superior stability even under challenging vibration and shock environments. Additionally, the system is cost-effective and is anticipated to have diverse industrial applications.

We develop a novel broadband comb light source for sensing multiple fiber Bragg gratings (FBGs). This broadband light source is realized through a Fabry-Pérot laser with intracavity saturable absorbers (FP-SA), which is a new type of low-cost and highly integrated semiconductor laser solution. The laser chip measures 1500 μm in length and 300 μm in width. Based on a waveform shaper and the FP-SA laser, we successfully generated the output of a broadband comb light source. By adjusting the filter bandwidth, laser gain voltage, and reverse voltage, we were able to tune the output bandwidth of the light source across a wide range from 2.5 nm to 25 nm. We propose a fitting method that leverages peak value extraction, tailored to the unique output characteristics of this source. Experimental results demonstrate that, when utilizing the FP-SA laser with a comb wavelength spacing of 0.23 nm, the demodulation repeatability achieves ±3.5 pm, and the demodulation linearity exceeds 0.9996. To the best of our knowledge, this work presents a new high-performance integrated broadband light source option for quasi-distributed FBGs array sensing systems.