Organic dye-doped polymers have been widely investigated as gain media in solid-state dye lasers. Dye molecules which have large absorption and induced emission cross sections due to allowed π-π transitions are ideal active dopants for the generation and amplification of intense light pulses. However, continuous wave operation is not feasible with organic dyes because of the triplet losses. On the other hand, lanthanide ions that have long metastable state lifetimes are widely used in silica glass-based fiber amplifiers and for both continuous and pulsed lasers. It has been more than 30 years since the first lanthanide lasers were reported.1-3 During this period a wide variety of lanthanide lasers and amplifiers have been investigated, and extensive progress has been made by many researchers. Many reviews have been written concentrating primarily on the physical and chemical properties of lanthanides in many matrices for laser action.4-8 Recently, several books have focused on lanthanide-doped fiber amplifiers for optical communications.9-11 The success of lanthanide-doped fiber amplifiers has inspired thousands of publications and continues to motivate research on the many diverse components that are required in these systems. Optical links are now used primarily in applications such as telecommunications with single-mode silica optical fibers, which have the ability to provide high-bandwidth and long-distance communications. However, as the demand for bandwidth increases in the office and home, it has become increasingly important to develop very low cost optical links that can be readily installed by users. Plastic optical fibers (POF) have received increasing attention because of their clear technical advantages over glass fibers, such as flexibility and a large core diameter, which enables efficient connection and coupling resulting in a low-cost system for a local area network. Recently a low-loss (100 db/km), highbandwidth 5.12 GHz for 100 m transmission graded index plastic optical fiber (GI-POF) has been developed.12 Also, an all fluorinated POF, whose low loss region is extended to the visible and near-infrared, has been successfully prepared.13 Plastic optical fiber amplifiers (POFA) that generate signal light in the visible and near-infrared are potentially important because of their adaptability for POF-based short span optical local distribution networks. This review describes recent progress on plastic optical fiber lasers and amplifiers with lanthanides. We focus especially on the design and selection of plastic optical fiber and chelate materials.

Plastic optical fiber lasers and amplifiers containing lanthanide complexes.

Chapter 225 – Rare-earth beta-diketonates

Solid-state organic amplifiers and lasers are attractive for hybrid integration due to their compatibility with different material platforms, straightforward processing, and possibility to optimize easily their optical and electronic properties by molecular engineering. Advances in the gain medium design and synthesis in combination with new resonator architectures led to tremendous improvements in temporal and spectral properties, lifetime stability, gains produced and operating threshold powers, which triggered interest in their use for a broad range of integrated photonic applications. In this contribution, the current state-of-the-art in the field of organic solid-state amplifiers and lasers is reviewed from the aspects of fabrication technology, gain materials, and device performance. Furthermore, examples of the progress of this technology from a laboratory curiosity to one that demonstrates practical integrated photonic applications are highlighted. An outlook is also provided on research areas and applications that are likely to shape further developments of this technology.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/lpor.201100034

Organic solid-state integrated amplifiers and lasers

We report the fabrication and characteristics of planar microcavities in a log-pile photonic crystal structure formed using light-induced photopolymerization of resin. A planar defect was introduced into the middle of the log-pile structure as a single layer with every second rod missing. The existence of confined cavity states was confirmed experimentally and by numeric simulations. The cavity resonance found at the midgap wavelength λM∼4.0 μm had a quality factor of about 130.

Microcavities in polymeric photonic crystals

Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400‐3800 cm −1 range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm −1 with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm −1 in PMMA are calculated in relation to that of toluene.

https://iopscience.iop.org/article/10.1088/1464-4258/10/5/055303/pdf

Raman spectra of polymethyl methacrylate optical fibres excited by a 532 nm diode pumped solid state laser

A graded-index polymer optical fiber containing rhodamine 6G in poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) has been fabricated. Lasing behavior of the fiber was observed by pumping with a frequency-doubled Q-switched Nd: yttrium–aluminum–garnet laser. A slope efficiency of 43% and a lifetime of 110 000 shots at a repetition rate of 10 Hz have been observed. With a 1.5 mJ pump energy, an output energy of 640 μJ was produced.

High-efficiency organic dye-doped polymer optical fiber lasers

Neodymium, praseodymium and erbium ions are successfully incorporated into the core of deuterated polymer-based optical fibres. The spectra of three fibres have several strong absorption bands in the visible and infrared regions. The fluorescence lifetime (6.24 /spl mu/s) at 1060 nm of Nd-chelate doped plastic optical fibre with an uncooled photodiode is obtained.

Fabrication and optical properties of neodymium-, praseodymium- and erbium-chelates-doped plastic optical fibres

The absorption spectra of neodymium (Nd), praseodymium (Pr), erbium (Er), and thulium (Tm) ions in perfluorinated (PF) plastic solutions were measured, and the Judd–Ofelt parameters of the Er and Nd ions have been calculated. The radiative properties of the Nd and Er ions in PF plastic solutions were determined from the absorption measurements and the Judd–Ofelt theory. The fluorescence spectrum of Nd3+ in a PF plastic solution from 900 nm to 1350 nm was measured for the first time, to our knowledge. Furthermore, the PF plastic films containing lanthanide chelates were fabricated by spin coating, and the refractive indices of the films were measured.

Spectroscopic properties of lanthanide chelates in perfluorinated plastics for optical applications

We report what is to our knowledge the first observation of erbium fluorescence at the optical communication wavelength of 1.5 µm in a perfluorinated medium. Using a Nd:YAG (355-nm) source, we observed fluorescence of the I413/2–I415/2 transition with a peak wavelength of 1.535 µm and with a full width at half-maximum of 28 nm. These results can lead to new active devices that use all-fluorinated polymers.

Observation of fluorescence in an optically pumped erbium-containing perfluorinated medium at 1.5 μm

Neodymium, praseodymium, and erbium ions have been successfully incorporated into the core of deuterated polymer-based optical fibers. The spectra of these fibers have several strong absorption bands in the visible and infrared regions.

Yukihisa Nishizawa

Papers

High-efficiency organic dye-doped polymer optical fiber lasers

Fabrication and optical properties of neodymium-, praseodymium- and erbium-chelates-doped plastic optical fibres

Spectroscopic properties of lanthanide chelates in perfluorinated plastics for optical applications

Observation of fluorescence in an optically pumped erbium-containing perfluorinated medium at 1.5 μm

Plastic optical fibers containing neodymium-, praseodymium-, and erbium-chelates for optical amplification