Cascaded Mach–Zehnder Architectures for Photonic Integrated Delay Lines

Waqas, Abi; Melati, Daniele; Melloni, Andrea

doi:10.1109/lpt.2018.2865703

Cited by 31 publications

(11 citation statements)

References 17 publications

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“…When the delay line is set into its rest state (∆τ = τ 0 ), the length difference between the lower and the upper arm after the input beamsplitter must be ∆L = v p1 ( τmax 2 − τ 0 ). Among the different devices which can physically implement the delay line, a good candidate is the one based on cascaded asymmetric Mach Zendher Interferometers (aMZI) reported in [40]. This device is attractive since it can be easily reconfigured using thermo optic phase shifters, it is built using standard and robust optical components, and has a broadband spectral response.…”

Section: Mitigating Indistinguishability Issues In Two Photon In-terf...mentioning

confidence: 99%

Mitigating indistinguishability issues in photon pair sources by delayed-pump Intermodal Four Wave Mixing

Borghi,

Pavesi

2022

Preprint

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Large arrays of independent, pure and identical heralded single photon sources are ubiquitous in today's Noise Intermediate Scale Quantum devices (NISQ). In the race towards the development of increasingly ideal sources, delayed-pump Intermodal Four Wave Mixing (IFWM) in multimode waveguides has recently demonstrated record performances in all these metrics, becoming a benchmark for spontaneous sources in integrated optics. Despite this, fabrication imperfections still spoil the spectral indistinguishability of photon pairs from independent sources. Here we show that by tapering the width of the waveguide and by controlling the delay between the pump pulses, we add spectral tunability to the source while still inheriting all the record metrics of the IFWM scheme. This feature is used to recover spectral indistinuishability in presence of fabrication errors. Under realistic tolerances on the waveguide dimensions, we predict > 99.5% indistinguishability between independent sources on the same chip, and a maximum degradation of the Heralded Hong Ou Mandel visibility < 0.35%.

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Section: Mitigating Indistinguishability Issues In Two Photon In-terf...mentioning

confidence: 99%

Mitigating indistinguishability issues in photon pair sources by delayed-pump Intermodal Four Wave Mixing

Borghi,

Pavesi

2022

Preprint

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“…Upon its realization, the system was used to scan different layers of finger tip [10]. Cascaded MZI with tunable couplersbased delay line with delay tuning range of 124 ps was reported at 1550 nm central wavelength [11]. Recently cascaded MRRs on 3 4 platform was proposed.…”

Section: Introductionmentioning

confidence: 99%

“…Comparative analyses for all three modes were done and it is found that TM mode being the most promising candidate with minimal propagation losses. The reported compact reference delay line upon realization along with integrated directional coupler [10][11] will completely replace the bulky fiber-based interferometer in a Fourier domain OCT system.…”

Section: Introductionmentioning

confidence: 99%

Design and Simulation of Ultra low loss Spiral Delay line for Integrated Optical Coherence Tomography

et al. 2021

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We report a design of 55 cm long spiral delay line at 850 nm wavelength. Propagation characteristics were simulated and analysed with fully vectorial Eigen Mode Expansion (EME) method. Bending losses were calculated and analysed for the optimization of minimum bending radius for reported structure. We have also simulated and analysed excess loss for a broadband of 200 nm at 850 nm operating wavelength. An excess loss of less than 0.2 dB is reported for the structure over the entire bandwidth range. The structure was further simulated for individual Transverse Electric (TE) and Transverse Magnetic (TM) modes and the analysis showed better results for TM mode. Reported structure is easy to fabricate, ultra-low loss and also broadband over 200 nm with a foot print of only 6×6 sq. mm. So, this design will improvise the reference arm section and will enhance the depth scanning of integrated optics based optical coherence tomography system.

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“…Ring resonators and photonic crystals are the most common elements used to construct controllable PICs, able to continuously tune the group delay up to several hundreds of picoseconds and even a few nanoseconds [4]. Ring resonators exploit their resonant spectral behavior to achieve compact-footprint devices at the expense of narrow bandwidth [13]. The miniaturization of ODL components also improves the tuning speed.…”

Section: Introductionmentioning

confidence: 99%

“…From Equation (13), the group delay is a function of both φ 1 and φ 2 . Therefore, the tuning of φ 2 for tuning the group delay will change the resonant wavelength where the peak group delay is located.…”

Section: Introductionmentioning

confidence: 99%

Tunable Optical Delay Line Based on a Racetrack Resonator with Tunable Coupling and Stable Wavelength

Hailu

Lee

2019

Applied Sciences

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For optical sensing or biomedical sensing where the light source usually has a stable and narrow linewidth, the design rule of the tunable optical delay line (ODL) can be different from the ODLs for optical communications and buffering. We present here a novel way to tune a racetrack resonator-based ODL by push-pull operation to stabilize the resonant wavelength. Full device simulation that accounts for the thermal tuning effect and the photonic characteristics of the whole integrated device is conducted to verify the characteristics of the tunable ODLs. With the simple racetrack resonator, the group delay can simply be tuned by changing the coupling coefficient of the resonator while the wavelength is stabilized by tuning the racetrack loop. A tuning of hundreds of picoseconds is achievable with a very compact device and small power consumption.Many different integration platforms can be utilized to make ODLs. Basic trade-offs between the integration density and waveguide propagation loss need to be considered before choosing the proper platform. The silicon photonics platform based on the silicon-on-insulator (SOI) is regarded as one of the most promising technologies for large-scale high-density photonic integration because of its large index contrast, small bending radius, and use of compatible fabrication facilities in semiconductor foundries [5,17]. Currently, there are several semiconductor foundries and research institutes providing the multi-project-wafer (MPW) process for SOI-based photonic integration, which can reduce the research and development cost for realizing tunable ODLs. Therefore, our design is based on the SOI platform.There are two commonly used approaches to tune the SOI-based ODLs: Tuning with thermal heating or carrier-induced effects. Both tuning mechanisms change the refractive index of the waveguide and then change the phase. However, the carrier-induced effect via carrier injection or depletion requires the formation of a PN junction in the waveguide, and the refractive index change is associated with a loss change. Therefore, thermal tuning is usually the choice for its simple device structure and low optical loss as long as the tuning speed is not the major concern. In fact, the thermal tuning speed can be as short as a few µs for the local heating of a compact SOI waveguide [20]. The high thermal resistance of the silica cladding on a SOI structure can also reduce the thermal crosstalk and power consumption.Tunable ODLs based on ring resonators have been demonstrated by several groups [21][22][23][24][25]. Most of the designs are for optical signal processing or buffering. In these applications, the critical requirements include a large enough true delay, wide bandwidth, and low higher-order phase variations that will lead to dispersion and signal distortions. Therefore, multiple stages of ring resonators are employed to achieve the desired delay with large bandwidth and low distortion [4]. However, the manufacturing variations in the associated multiple rings will result in fluct...

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Cascaded Mach–Zehnder Architectures for Photonic Integrated Delay Lines

Cited by 31 publications

References 17 publications

Mitigating indistinguishability issues in photon pair sources by delayed-pump Intermodal Four Wave Mixing

Mitigating indistinguishability issues in photon pair sources by delayed-pump Intermodal Four Wave Mixing

Design and Simulation of Ultra low loss Spiral Delay line for Integrated Optical Coherence Tomography

Tunable Optical Delay Line Based on a Racetrack Resonator with Tunable Coupling and Stable Wavelength

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