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We introduce wavelength conversion technology for wideband transmission over deployed optical fibers by extending the wavelength range within the optical fiber transparent window which is not yet supported by practical transceivers.

We focus on the introduction of a multi-wavelength-band transmission system based on all optical wavelength conversion, which increases the transmission capacity in the deployed fiber infrastructure without the need for new wavelength band transceivers.

We have demonstrated real-time S+C+L triple-band WDM transmission of coherent 200-Gb/s (34-Gbaud DP-16QAM) signals by employing all-optical wavelength converters. 100-nm wavelength range (1504.98–1606.82 nm) transmission over 40 km is realized by using only transceivers operating at C-band.

We successfully developed a high-density broadband 16-channel × 25 Gb/s on-package silicon photonics optical transceiver. The flip chip bonded bridge structure realized high density of about 363 Gb/s/cm2 . We demonstrated simultaneously on all 16 channels error-free operations with low crosstalk penalties of Tx-to-Tx 1.4 dB, Rx-to-Rx 1.4 dB, and Tx-to-Rx

We successfully developed a high density broadband 16-channel × 25 Gb/s silicon photonics optical transceiver. The flip chip bonded structure realized the density of about 363 Gb/s/cm2. We demonstrated the simultaneous multichannel error free operations with low crosstalk penalties.

We developed high-density silicon-photonics multichannel receiver and demonstrated 12ch × 25 Gb/s error-free operations at the bit-error-rate of < 1E-12 for the pseudo random binary sequence (PRBS) of 231−1 signals. Carefully designed high power integrity successfully led to very small crosstalk penalty of 1.2 dB under the simultaneous operation at all 12 channels.

We propose an image cross-connector using an organic photorefractive polymer. With this device, it is possible to perform a reconfigurable connection between multiple input–output image ports by setting the incident angle of individual control beams to minute levels. The use of a polymer can reduce the thickness of the index grating to be induced inside the medium, which can also reduce the distortion of the output image and bring about high precise image connection without an additional optical system. We conduct an experiment with a hole-transport polymer PATPD to verify the operations of an image cross-connector, in which different images from a vertical array of input images would be connected separately to two output ports by two control beams that were injected at different angles.

Low-loss connections between no-polish optical fibers were realized by using a combination of elastically deformable connectors and a laser cleaving process. The elastic connectors have an elastically deformable mechanism, which enables one to cancel out variations both in the fiber length in a fiber ribbon and in the fixed positions of the fiber ribbons in the connectors. A laser cleaving process was employed to cleave no-polish fiber facets. The fiber facets show slightly protruded convex shapes, which were almost the same as those of the polished facets. We confirmed that physical contact connections between the laser-cleaved no-polish fibers in the elastic connectors were realized. The average insertion loss and return loss of cables including connection between the no-polish fibers in elastic connectors were 0.19 dB and 23.4 dB, respectively. The values were almost the same as those of cables including connection between polished fibers in mechanically transferable connectors. Furthermore, the durability of the connections between the elastic connectors over 250 repeated mating/dematings in a high-density mid-plane connector housing was also confirmed.

An elastic optical multifiber connector compatible with a standard mechanically transferrable connector was realized. The elastic connector has N-shape folded frame parts which are elastically deformable of 100 μm. Physical contact connections between no-polish fibers and a film-waveguide were confirmed. The average insertion loss of the cables terminated at one side with an elastic connector shows 0.16 dB which is almost same as those terminated at both ends with mechanical transferrable connectors. The durability for 250 times mating/demating tests in a mid-plane connector housing were also confirmed. Furthermore, the laser-cleaved fiber facets have smooth surfaces and convex shapes like those of polished connectors. Using the connector and the process, physical contact connections between no-polish fibers were achieved.

We developed a novel low-cost polish-less elastically deformable optical multifiber backplane connector. The ferrule deformation and fibers buckling were enabled to cancel the variation in the lengths of unpolished cut fibers. We confirmed the physical contact connection between unpolished cut fibers in the ferrule and a polymer waveguide in a connector for polymer-waveguides connected with mechanical transfer connector (PMT) ferrule. The connection loss is almost the same as that between a conventional polished mechanical transfer (MT) ferrule and the PMT ferrule. We prepared a connector housing to mount the ferrules on a backplane/midplane. The insertion loss and return loss results in the housing show no degradations during 200 mating/demating tests, and there were no fiber breakages or damage to the waveguide core.

We propose and demonstrate a novel low-cost elastic optical multifiber connector to realize optical interconnections. The ferrule deformation and fibers buckling are enable to cancel the variation in lengths of unpolished cut fibers. We confirmed a physical contact connection between the ferrule and a PMT ferrule. The connection loss was almost the same as that between a conventional polished MT and the PMT. Also, we prepare A connector housing for mounting the ferrules on a MP is prepared. The insertion loss and return loss measurements in the housing shows no degradations during 250 mating/demating tests.

High-density single-mode polymer waveguides were fabricated for chip-to-chip optical interconnection. The waveguides were designed as minimized mode field diameters for the lowest inter-channel crosstalk caused by mode coupling. The optimum relative index difference chosen was 1.2% to ensure compatibility with low crosstalk and wide fabrication tolerances. The 60-mm-length linear waveguides demonstrated a low propagation loss of 0.6 dB/cm and -45 dB crosstalk at 1310 nm. Also, a new crosstalk mechanism for a curved waveguide was revealed.