Erbium And Thulium Co-doped(S+C)-band Organic Optical Waveguide Amplifiers

With the development of information technology such as the Internet of Things,artificial intelligence,and cloud computing,people’s demand for network data traffic keeps increasing.Researchers need to broaden the operation band of optical communication networks to meet the rapidly increasing demand for data traffic.Integrated photonics components are important parts of optical networks,and the capacity of optical networks can be expanded effectively only when the bandwidth of integrated photonics components is matched with optical networks.The low-loss bands of optical networks include T-band,O-band,E-band,S-band,C-band,L-band,U-band,etc.At present,the research on organic optical waveguide amplifiers mainly focuses on the design and preparation of C-band（1530 nm-1565 nm）devices,and research of other bands is relatively rare.If the operating band of rare-earth doped organic optical waveguide amplifiers can be extended from C-band to（S+C）-band（1460 nm-1565 nm）,an innovative breakthrough in this field can be achieved.Thulium ions(Tm³⁺)and erbium ions(Er³⁺)can achieve light emission in S-band and C-band,respectively.In principle,the broadband gain in the（S+C）-band can be obtained in Tm³⁺and Er³⁺co-doped optical waveguide amplifiers.However,designing such a device has the following challenges:（1）The luminous performance of Tm³⁺-single-doped materials in the S-band needs to be improved;（2）There are few studies on S-band organic optical waveguide amplifiers,and no relevant reports have been seen from other research groups except ours;（3）If thulium and erbium ions are simply co-doped in the gain medium,the fluorescence quenching caused by energy transfer between them is a problem that must be solved.In order to solve the above problems and successfully prepare the Er³⁺-Tm³⁺co-doped（S+C）-band organic optical waveguide amplifier,a series of works have been carried out in this paper.The main contents and innovative results are listed below:1.The Tm³⁺-doped polymer optical waveguide amplifier was designed and fabricated.Na YF₄:Tm,Yb nanoparticles,which emitted light（～1480 nm）in S-band,were synthesized by high-temperature thermal decomposition method using an automatic nano-synthesizer,then copolymerized with methyl methacrylate monomer to prepare a composite polymer gain medium.Organic optical waveguide amplifiers were prepared using the gain medium.When the signal optical power was 1 m W,a relative gain of about 5.6 d B/cm was obtained at the wavelength of 1480 nm.2.The gain enhancement of polymer optical waveguide amplifiers in the S-band was studied.By using the energy transfer between thulium ion and cerium ion(Ce³⁺),the emission intensity of nanoparticles at 1480 nm was enhanced by co-doping thulium and cerium ions together.After the introduction of the cerium ion,the gain of the polymer optical waveguide amplifier in the S-band was increased by 5.4 d B,and the maximum relative gain reached 12.7 d B.This result was the largest gain reported for polymer optical waveguide amplifiers in the S-band.3.The wideband optical waveguide amplifier with gain covering（S+C）-band was developed for the first time by doping rare earth ions in the different layers of the waveguide.Na YF₄:Tm,Yb and Na YF₄:Er,Yb nanoparticles were synthesized,and two gain media were prepared as the core layer and the upper layer of the rectangular waveguide,respectively.When the signal power was 1 m W,the device could provide a relative gain of up to 4.5 d B in the S-band and 8.7 d B in the C-band,which was the first（S+C）-band broadband gain obtained in the polymer waveguide amplifiers.4.Core-multishell nanoparticles with thulium and erbium ions layered doping were synthesized,and the energy transfer between thulium and erbium ions was suppressed by an inert shell.An optical waveguide amplifier with uniform gain in（S+C）-band was successfully prepared.The Na YF₄:Tm,Yb@Na YF₄@Na YF₄:Er nanoparticles were prepared,and relatively flat luminescence in（S+C）-band was obtained.The device prepared by these nanoparticles could provide relatively uniform gain in the（S+C）-band.When the signal power was 1 m W,the device could provide a maximum relative gain of 8.5 d B.It was the first time that the uniform broadband gain in the（S+C）-band was obtained on an organic waveguide amplifier.