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We designed and fabricated a functionally integrated optical waveguide illuminator specially for common-path digital holographic microscopy through random media. The waveguide illuminator creates two point sources with desired phase shifts, which are located close to one another so that the common-path condition of the object and reference illumination is satisfied. Thereby, the proposed device permits phase-shift digital holographic microscopy free from bulky optical elements such as a beam splitter, an objective lens, and a piezoelectric transducer for phase shifting. Using the proposed device, microscopic 3D imaging through a highly heterogeneous double-composite random medium was experimentally demonstrated by means of common-path phase-shift digital holography.

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We demonstrate a silica-based planar waveguide spatial heterodyne spectrometer incorporating 120° optical hybrid 3×3 MMI couplers as the output couplers in 32 MZIs, which enabled us to derive the spectrum without use of the previously reported dynamic phase shifting. The free spectral range was 640 GHz, and the spectral resolution was 14 GHz. We used a CO2 laser irradiation method to calibrate the light powers from all the output ports of the couplers and to measure the optical phases and amplitudes at the individual MZIs. We solved the resultant system of three linear equations at each MZI and performed a complex Fourier transformation to derive a narrowband light spectrum. The background noise level of the retrieved spectrum was 0.05 with respect to the peak even when no window function was applied.

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Silicon reflection-type arrayed-waveguide gratings (AWGs) consisting of all straight array waveguides are experimentally demonstrated for the first time to our knowledge. The AWG has 14 output channels with 400 GHz channel spacing and a footprint of 230 µm×530 µm. The minimum on-chip loss of 3.0 dB and crosstalk of -20 dB are achieved by using a second-order distributed Bragg reflector facet.

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We calculate the root mean square (rms) value of the spectral noise caused by optical path phase measurement errors in a spatial heterodyne spectrometer (SHS) featuring a complex Fourier transformation. In our calculation the deviated phases of each Mach-Zehnder interferometer in the in-phase and quadrature states are treated as statistically independent random variables. We show that the rms value is proportional to the rms error of the phase measurement and that the proportionality coefficient is given analytically. The relationship enables us to estimate the potential performance of the SHS such as the sidelobe suppression ratio for a given measurement error.

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This paper discusses the architecture and provides performance studies of a silicon photonic chip-scale optical switch for scalable interconnect network in high performance computing systems. The proposed switch exploits optical wavelength parallelism and wavelength routing characteristics of an Arrayed Waveguide Grating Router (AWGR) to allow contention resolution in the wavelength domain. Simulation results from a cycle-accurate network simulator indicate that, even with only two transmitter/receiver pairs per node, the switch exhibits lower end-to-end latency and higher throughput at high (>90%) input loads compared with electronic switches. On the device integration level, we propose to integrate all the components (ring modulators, photodetectors and AWGR) on a CMOS-compatible silicon photonic platform to ensure a compact, energy efficient and cost-effective device. We successfully demonstrate proof-of-concept routing functions on an 8 × 8 prototype fabricated using foundry services provided by OpSIS-IME.

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Spatial heterodyne spectrometers (SHS) can achieve high resolution with excellent optical throughput. We demonstrate a planar waveguide SHS incorporating 64 asymmetric Mach-Zehnder interferometers and show measurements that verify 1 GHz resolution across a 64 GHz measurement range.

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We report that a spectrum can be retrieved with a planar waveguide spatial heterodyne spectrometer (SHS) incorporating an active phase-shift scheme, where the phase shifts are distributed around π/2. This was confirmed experimentally with an SHS that had 32 interleaved Mach-Zehnder interferometers and whose free spectral range was 625 GHz. The phase shifts ranged from 0.71 to 2.2 rad against the target of π/2 rad.

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We describe a configuration of the integrated-optic spectrometer based on Fourier-transform spectroscopy. The original source spectrum has been successfully retrieved with 20 GHz resolution by the spectrometer implemented in a silica-based planar waveguide.

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We propose a multiple star wavelength division multiplexing-passive optical network (WDM-PON) to serve several subscriber groups located at a widely distributed area. The architecture based on a band splitting WDM (BSWDM) filter separates upstream and downstream bands to several sub-bands and assign them to different subscriber groups. As a result, it enables to use a single type AWG for second stage splitting points. Thus, it provides color-free outside plant and simplifies management issues. The proposed architecture also provides pay as you grow feature.

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We demonstrate parabolic optical pulse generation by manipulating the intensity and phase of individual longitudinal modes of a 40 GHz picosecond optical pulse train in the spectral domain. Bright and dark parabolic pulses were generated from a 40 GHz mode-locked fiber laser using a 64-channel arrayed waveguide grating pulse shaper. The obtained parabolic pulse, which can easily generate a linear chirping, is useful for a number of applications to optical signal processing applications, including pulse compression and time-domain optical Fourier transformation.