Light-induced Self-written Waveguide Research Articles

Polymer tapered pillar on a fiber end fabricated by UV irradiation using a high-NA fiber

The increasing need for single-mode fibers (SMFs) and advances in silicon photonics (SiPh) devices have led to the need for an efficient method of optical coupling between them. To achieve a higher coupling between them, a polymer tapered pillar was fabricated on the end face of the SMF by applying the optical diffraction effect and a self-written waveguide technology using a high numerical aperture (HiNA) fiber. The initial 10.4 µm spot size was reduced to 4.17 µm at 1.55 µm wavelength, and the greatest coupling efficiency of –1.01 dB was reached between an SMF with a tapered pillar and uncured resin cladding and a HiNA fiber. Full Text: PDF ReferencesR. Marchetti, C. Lacava, L. Carroll, K. Gradkowski, P. Minzioni, "Coupling strategies for silicon photonics integrated chips [Invited]", Photonics Res. 7, 201 (2019). CrossRef R. Bachelot, C. Ecoffet, D. Deloeil, P. Royer, D.-J. Lougnot, "Integration of micrometer-sized polymer elements at the end of optical fibers by free-radical photopolymerization", Appl. Opt. 40, 5860 (2001). CrossRef P. Pura, M. Szymanski, M. Dudek, L.R. Jaroszewicz, P. Marc, M. Kujawinska, "Polymer Microtips at Different Types of Optical Fibers as Functional Elements for Sensing Applications", J. Lightwave Techn. 33, 2398 (2015). CrossRef O. Mikami, R. Sato, S. Suzuki, C. Fujikawa, "Polymer Microlens on Pillar Grown From Single-Mode Fiber Core for Silicon Photonics", IEEE Photonics. Technol. Lett. 32, 399 (2020). CrossRef Y. Kamiura, T. Kurisawa, C. Fujikawa, O. Mikami, "High optical coupling efficiency of polymer microlens and pillar on single mode fiber for silicon photonics", Jpn. J. Appl. Phys. 61, SK1009 (2022). CrossRef F. Tan, H. Terasawa, O. Sugihara, A. Kawasaki, T. Yamashita, D. Inoue, M. Kagami, C. Andraud, "Two-Photon Absorption Light-Induced Self-Written Waveguide for Single-Mode Optical Interconnection", J. Lightwave Tech. 36, 2478 (2018). CrossRef H. Terasawa, O. Sugihara, "Near-Infrared Self-Written Optical Waveguides for Fiber-to-Chip Self-Coupling", J. Lightwave Technol. 39, 7472 (2021). CrossRef K. Vanmol, K. Saurav, V. Panapakkam, H. Thienpont, N. Vermeulen, J. Watté, J. Van Erps, "Mode-field Matching Down-Tapers on Single-Mode Optical Fibers for Edge Coupling Towards Generic Photonic Integrated Circuit Platforms", J. Lightwave Tech. 38, 4834 (2020). CrossRef Y. Saito, K. Shikama, T. Tsuchizawa, H. Nishi, A. Aratake, N. Sato, "Tapered Self-Written Waveguide between Silicon Photonics Chip and Standard Single-Mode Fiber", Opt. Fiber Communication Conference (OFC2020), paper W1A.2, (2020). CrossRef Y. Saito, K. Shikama, T. Tsuchizawa, N. Sato, "Tapered self-written waveguide for a silicon photonic chip I/O", Opt. Lett. 47(12), 2971 (2022). CrossRef N.A. Baharudin, C. Fujikawa, O. Mitomi, A. Suzuki, S. Taguchi, O. Mikami, S. Ambran, "Tapered Spot Size Converter by Mask-Transfer Self-Written Technology for Optical Interconnection", Photon. Technol. Lett. 29, 949 (2017). CrossRef H. Nawata, K. Ohmori, Proc. International Conference on Electronics Packaging (ICEP), paper 23 (2014) DirectLink S. J. Frisken, "Light-induced optical waveguide uptapers", Opt. Lett. 18, 1035 (1993). CrossRef Y. Obata, Y. Oyama, H. Ozawa, T. Ito, O. Mikami, T. Uchida, "Multi-array Self-written Waveguides using Photo-mask for Optical Surface Mount Technology", International Conference on Electronics Packaging (ICEP), paper 225 (2005). DirectLink P. Yin, J.R. Serafini, Z. Su, R. Shiue, E. Timurdogan, M.L. Fanto, S. Preble, "Low connector-to-connector loss through silicon photonic chips using ultra-low loss splicing of SMF-28 to high numerical aperture fibers", Opt. Expr. 27, 24188 (2019). CrossRef https://coherentinc.force.com/Coherent/UHNA3?cclcl=en_US, (18/09/2022). DirectLink

Optically formed rubbery waveguide interconnects.

Light induced self-written waveguides (LISWs) with unique elongation characteristics and low optical loss are formed in a monodispersed polyisoprene solution using a low-power laser photopolymerization process, while their light transmission characteristics are exemplified in the flexible interconnection of two single-mode optical fibers operating in the visible/near infrared wavelengths. The LISWs formed exhibit rubbery properties, allowing extensibilities upon cases from 400% to 800%, while still retaining significant optical transmission. The rubber elasticity enables sustaining LISWs at stressed lengths longer than 500 µm propagation losses from 1.0 to 2.9 dB/mm.

Near-Infrared Self-Written Optical Waveguides for Fiber-to-Chip Self-Coupling

The light-induced self-written (LISW) waveguide technique is a promising candidate for the practical realization of a passive alignment between telecommunication and silicon photonic devices. While silicon is transparent to wavelengths above 1100 nm, the one-photon polymerization wavelength range is limited below 1100 nm. In this study, LISW waveguide fabrication at telecommunication wavelengths was demonstrated using a single-photon photopolymerizing resin. The LISW waveguide fabrication threshold values are lower than that of the two-photon photopolymerization system by six to seven orders of magnitude. LISW waveguides are fabricated from a single-mode fiber, a vertical-cavity surface-emitting laser, and a silicon waveguide. Using this technique, fiber-to-chip self-coupling between silicon photonic devices at telecommunication wavelengths is demonstrated. The results demonstrate the potential of the LISW technique for optical self-coupling of telecommunication and silicon photonic devices.

Two-Photon Absorption Light-Induced Self-Written Waveguide for Single-Mode Optical Interconnection

We propose two-photon absorption light-induced self-written (LISW) waveguide formation using short-wavelength infrared pulse laser light. It is suitable and efficient for single-mode optical interconnection, and also promising for small-core single-mode optical interconnection. The approach offers the possibility of not only decreasing the insertion loss, but also reducing the interconnection task time. We assessed this approach for single-mode optical interconnection. We obtained an LISW waveguide loss of about 0.06 dB for an LISW waveguide length of 100 μ m and a connection loss per facet of about 0.37 dB. We also presented the results on the interconnection between high-numerical-aperture small-core thermally-diffused expanded-core single-mode fibers having the mode field diameters of about 3 μ m by using the same approach. The results showed the present approach to be a promising alternative route for efficient interconnection of small-core single-mode optical devices, such as silicon nanowires with appropriate configurations.

Light-induced self-written waveguide fabrication using 1550 nm laser light.

Light-induced self-written (LISW) optical waveguides were fabricated for the first time, to the best of our knowledge, using a photopolymerizable resin system formed by 1550nm pulse laser light. A two-photon absorption (TPA) chromophore with a TPA cross section of several hundred Goeppert-Mayer (GM) at 1550nm was used. Furthermore, the optical interconnection between a single-mode fiber and a fiber Bragg grating was demonstrated by the present technique, using one-way irradiation of 1550nm laser light through the single-mode fiber. The LISW waveguide formation using 1550nm laser light offers a new and promising alternative route for optical interconnection in silicon photonics technology.

フォトニクスポリマを用いた次世代光接続：自己形成光導波路の展開

フォトニクスポリマを用いた次世代光接続：自己形成光導波路の展開

Light induced self-written waveguides interactions in photopolymer media.

We present experimental and theoretical study of the interaction of Light Induced Self-Written (LISW) waveguides in photopolymers. We show that the diffusion of the monomer controls the refractive index distribution. Consequently it influences the interaction between the LISW channels allowing the observation of anti-crossing behavior or the propagation of an array of non interacting LISW waveguides.

Electro-optic phase modulation in light induced self-written waveguides propagated in a 5CB doped photopolymer

We present the inscription of a Light Induced Self-Written (LISW) waveguide in a 4-cyano-4'-pentylbipheny (5CB) doped photopolymer. The dynamic reorientation of the 5CB molecules in the material under applied electric field leads to birefringence in LISW waveguide and thus allows the control of the phase of the guided mode.

Filamentation-free self-written waveguides in a photopolymerizable medium initiated by multimode optical fibers

The inscription of light-induced self-written waveguides (LISW) with multimode optical fibers cannot be achieved by using coherent light because of the filamentation phenomena coming from the interferences among the different propagating modes. To suppress this filamentation, we have used two distinct strategies, an incoherent light writing technique and an "on the flow" writing process, to demonstrate the buildup of 1.5 mm long multimode LISWs.

Self-written active waveguide for integrated optical amplifiers

The authors propose a fabrication method of optical amplifying devices, which is based on a technique of light-induced self-written waveguide. The waveguide structure doped with infrared organic dye molecules was self-written by visible laser light irradiation from optical fiber tips to photopolymerized resin, which makes the waveguide self-aligned with input and output fibers. The self-written “active” waveguides with the length of 0.98–1.89mm were fabricated and amplified spontaneous emission at ∼790nm was observed. Furthermore, optical amplification of externally input light was also implied in a tentative examination.

Serially grafted polymer optical waveguides fabricated by light-induced self-written waveguide technique

Serially grafted polymer optical waveguides were fabricated by the light-induced self-written (LISW) waveguide technique for the first time to our knowledge. To realize functional waveguide cores by the LISW technique, transparent materials at the writing wavelength were selected. By inserting thin transparent partitions, a serial-graft structure consisting of passive and active waveguides without any misalignment was realized automatically. This technique is advantageous for its extremely easy process over conventional fabrication techniques.

Polymer waveguide module for visible wavelength division multiplexing plastic optical fiber communication

We report a polymer waveguide module that provides bidirectional communication over a single plastic optical fiber (POF) with dual visible wavelength LEDs. The module is constructed using light-induced self-written waveguides, which enables a three-dimensional optical circuit for visible wavelength division multiplexing to be fabricated by an extremely simple process. We demonstrated 250 Mbits/s communication using a pair of these modules that each contained one green (lambda = 495 nm) and one red (lambda = 650 nm) LEDs by measuring the bit error rates. The results indicate that the system could transmit over more than 20 m of POF in full duplex mode.

Fabrication of light-induced self-written waveguides with a W-shaped refractive index profile

This paper proposes a novel technique for automatic waveguide formation by means of the self-trapping effect of optical fiber irradiation into a photopolymerizing resin. We investigate experimentally the phenomenon of thin cladding layer formation surrounding the core following the core creation. In the proposed technique, a counterdiffusion effect involving polymerizing monomers via the core/cladding interface causes enrichment of a low refractive index monomer, and a resultant "W-shaped" refractive index profile is realized. The measured propagation loss of the fabricated waveguide is 1.7 dB/cm at 0.68 /spl mu/m wavelength. This technology is appropriate for the fabrication of large-core optical waveguides of greater than 0.5 mm in diameter and is useful for automating the optical fiber connection and packaging process by virtue of being an all-passive optically induced process.

New Fabrication Method of Self-written Waveguide by Using Photosensitive Polyimide

A Photosensitive polyimide (PSPI) precursor for light-induced self-written (LISW) waveguide based on a poly(amic acid) (PAA) and 1,4-dihydropyridine derivatives (DHP)s has been developed. The PAA was prepared by ring-opening polyaddition of aromatic fluorinated tetracarboxylic dianhydrides and diamines. Upon exposing the PSPI precursor to laser light, a self-focusing effect induced by the difference in refractive index between the exposed and unexposed portions was observed. Thermal treatment of the laser exposed PSPI precursor gave a polyimide LISW wave guide with no other processing steps. The coupling loss between two multimode fibers with a 0.5 mm gap, was decreased from 5.2 dB in air to 0.7 dB by insertion of the PSPI LISW waveguide. This simple new fabrication method of LISW waveguide structures allows convenient and easy alignment of optical waveguide components.