A simple design of a temperature sensor is proposed and demonstrated using a fiber optic displacement sensor based on an intensity modulation technique. The proposed sensor uses a plastic optical fiber (POF)-based coupler as a probe in conjunction with a flat surface aluminum rod as a target. The aluminum rod is placed within the linear range of the sensor's displacement curve, which is from 0 to 1400 μm. The sensor is capable of measuring the temperature of an aluminum rod ranging from 42°C to 90°C with a measured sensitivity of 0.0044 mV/°C, with a linearity of more than 98% and a resolution of 2.4°C. The proposed sensor also shows a high degree of stability and good repeatability. The simplicity of design, accuracy, flexible dynamic range, and the low cost of fabrication are favorable attributes of the sensor and beneficial for real-field applications.

A Ti ₃ AlC ₂ MAX phase-based saturable absorber (SA) is successfully demonstrated to induce passive Q-switching in an erbium-doped fiber laser (EDFL) at the 1.5 μm region. The Ti ₃ AlC ₂ -PVA film is fabricated using the solution casting method and incorporated into the laser cavity which uses a 0.89 m long erbium doped fiber as the gain medium. Stable and self-starting Q-switched laser pulses are observed above a threshold pump power of 87.81 mW at a central wavelength of 1567.4 nm. The repetition rate is observed to increase from 24.07 kHz to 46.3 kHz, while the corresponding pulse width decreases from 5.0 μs to 0.99 μs over a pump power range of 108.9 mW to 244.5 mW. At the maximum pump power of 244.5 mW, the highest pulse energy of 102.7 nJ and the maximum output power of 4.75 mW are obtained. These findings demonstrated the feasibility of the Ti ₃ AlC ₂ MAX phase as an SA material with significant promise for photonic applications. This is also, to the best knowledge of the authors, the first report of a Ti ₃ AlC ₂ MAX phase-based SA for inducing passive Q-switching in an EDFL.

A passively Q‐switched erbium‐doped fibre laser was demonstrated by using tris‐(8‐hydroxyquinoline)aluminium (Alq ₃ ) organic material as a passive saturable absorber (SA). The SA was fabricated by a drop casting technique at room temperature and incorporated into a laser cavity by inserting it between two optical fibre ferrules. The Q‐switched fibre laser operates at a centre wavelength of 1559 nm with a full‐width half maximum of 1 nm. The generated pulse train is stable and has a pulse width decreased from 6.65 to 1.2 µs and the pulse repetition rate increased from 31.65 to 144.5 kHz as the pump power increased from 20 to 122 mW. The maximum pulse energy obtained is 63.89 nJ. This work indicates that the Alq ₃ as SA has a great potential to be utilised for pulsed laser generation. To the best of the authors' knowledge, this is the first time an organic material is utilised as a SA device for generating a stable Q‐switched laser pulse.