In this work, a transverse magnetic (TM)-pass polarizer based on subwavelength grating (SWG) on the emerging potential hybrid silicon-LNOI platform is proposed. By integrating silicon material onto the LNOI platform, the optical power of TE0 and TM0 modes is judiciously distributed to distinct regions. This design not only effectively blocks the TE0 mode but also enables low-loss transmission of the TM0 mode, thereby achieving a balanced manipulation of both polarizations. Due to the strong reflection of TE0 mode by SWG, a polarizer is realized with a high polarization extinction ratio (PER) and low insertion loss (73 dB and 0.37 dB respectively at 1550 nm) in a compact size (device length is 23.38 μm). Moreover, the PER is beyond 50 dB and the insertion loss is under 0.46 dB in a broad wavelength range of 1525 to 1585 nm.
We theoretically analyze the performances of the anti-PT-symmetric gyroscope near the exceptional point (EP). The results show that the frequency splitting caused by rotation is proportional to the square root of the fraction of power coupled from the bus to the ring. To fully exploit the potential of the EP, one needs to overcome two aspects of challenges. The first one is the preparation of sensitive unit, to detect the angular velocity of 104 deg / h with a micron-scale sensor; the allowable variation in the ratio of cavities’ radii is within the order of 10 − 16, which is exceedingly challenging in current nano fabrication. The other is controlling environmental disturbances. A temperature variation of 0.002°C would make the minimum detectable rotation rate up to 1010 deg / h, which is far beyond practically applications. Our analysis points out the difficulties in realizing this gyroscope, which has significant referential values to future work.
We propose a monolithic integrated cavity optomechanical accelerometer based on push-pull photonic crystal zipper cavity. The accelerometer integrates grating couplers, phase modulators, acceleration sensing unit, and electrostatic force feedback module on a chip. We use push-pull structure to eliminate the coupling crosstalk caused by paraxial acceleration and extend its range using electrostatic force feedback module. The transmissive photonic crystal zipper cavity structure is adopted to improve the integration and stability of the system. Accurate results are demonstrated as follows: the bandwidth is larger than 20 kHz, the mechanical sensitivity is 369 pm/g, the measuring range is ±100 g, and the noise equivalent acceleration is 5.06 μg / Hz. With its advantages, the accelerometer can be used in consumer electronics, aerospace, resource exploration, and other fields.
An integrated optical chip (IOC) is the phase modulation actuator in a closed-loop interferometric fiber optic gyroscope (IFOG). Research on temperature characteristic of IOC is meaningful for high-precision IFOG working in harsh environment. We focus on the temperature modeling of the IOC modulation phase error. In theoretical analysis, based on the temperature dependence of the IOC equivalent capacitance, a model between IOC modulation phase error and temperature is proposed. Through experiments, the variation tendency of the IOC equivalent capacitance with temperature is first presented. Subsequently, the IOC modulation phase error is demonstrated to be linear with temperature, which verifies the effectiveness of the proposed model. We provide an error research direction of IOC for high-precision fiber optic gyroscopes.
The integrated optical chip (IOC) is one of the most critical parts of the interferometric fiber optic gyroscope (IFOG). Unfortunately, the integral implementation of the IOC has a number of undesirable effects, which includes the modulation phase error. The inflexible influence of the modulation phase error on the bias error is analyzed in theory. For demonstrating, a method is found to measure the modulation phase error quantitatively. By experiment, the quantized parameter and its effect on bias error are presented. In addition, we offer a practical method to compensate the mentioned effect in IFOG, which is proved by the quantitative measurement. This study proposes a direction for IOC manufacturing inspection and evaluation.
We present a design of a laterally tapered optical waveguide mode-size converter from super luminescent diode (SLD) to silica-based planar lightwave circuit (PLC). The mode-size converter is based on silica-based PLC. By using three dimensional semi-vectorial beam propagation methods, laterally tapered waveguides with different boundaries are simulated and compared with each other, where the factors of polarization-dependent loss and coupling loss are mainly focused on. The results show that the most influential factor for polarization-dependent loss is the ratio of the divergence angle of SLD in the horizontal direction and the vertical direction. The refractive index difference Δ between core layer and cladding layer, core width of endface and taper length influence coupling loss mostly, while the effect of all side boundaries is within 0.05 dB. We also investigate the SLD misalignment tolerance and wavelength bandwidth’s impact on coupling loss. Furthermore, we examine the performance of the mode-size converter based on a particular SLD which has a divergence angle of 30°×45°. By optimizing the parameters of the tapered waveguide, the coupling efficiency is increased to 62.4% and the polarization-dependent loss is reduced to 0.035 dB. Meanwhile, it eΔnables us to reduce the coupling loss variation to 0.05dB with core width of endface fabrication tolerance of ±0.5 μm and taper length tolerance of ±0.5 mm. The proposed mode-size converter has been demonstrated to be well performed, implying its application in the optical transceiver module using SLD as light source and hybrid integration of III–V semiconductor waveguiding devices and PLCs.
The precise control of the thermal splicing temperature of ZBLAN fiber and silica fiber was guaranteed by theoretical simulation, analysis, and experimental optimization. The thermal splicing model was established, and optimized thermal splicing parameters were obtained based on the simulation results. The thermal splicing parameters were finely repeatedly tuned and optimized further in the thermal splicing experiments according to simulation parameters. The achieved loss was measured to be about 0.3 dB in the thermal splice experiments. The offset thermal splicing method demonstrated a repeatable, low-loss, and promising technique for the splice of ZBLAN fiber to silica fiber.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.