Optical true time delay based on contradirectional couplers with single sidewall-modulated Bragg gratings

Xu Wang; Shasha Liao; Jianji Dong

doi:10.1117/12.2247010

4 November 2016 Optical true time delay based on contradirectional couplers with single sidewall-modulated Bragg gratings

Xu Wang, Shasha Liao, Jianji Dong

Author Affiliations +

Proceedings Volume 10026, Real-time Photonic Measurements, Data Management, and Processing II; 100260C (2016) https://doi.org/10.1117/12.2247010
Event: SPIE/COS Photonics Asia, 2016, Beijing, China

Abstract

We propose and demonstrate optical true time delay using tapered SOI contradirectional couplers with single sidewallmodulated Bragg gratings. The contradirectional couplers consist of two tapered rib waveguides with different width, and the Bragg gratings are modulated in the inner sidewall of the wider one. The optical signal is launched from the wide waveguide and coupled to the narrow waveguide through the Bragg gratings structure. Along the direction of light propagation, the waveguide width varies linearly, so the reflection wavelength is different at different positions. Therefore, linear delay line can be realized within the grating passband using the present structure. In the simulation, grating period is 310nm and grating number is 2400, corresponding to the grating length of 744μm. Using 2.5D FDTD simulation, the current structure can realize optical group delay of 20ps within bandwidth of 18nm. The proposed device is fabricated on a 220nm SOI chip with Electron Beam Lithography (EBL) and Inductively Coupled Plasma (ICP) etching. In the experiment, continuous light is modulated by 10GHz radio-frequency signal and travel through the chip, which is finally detected by the oscilloscope. By adjusting the wavelength of input light, group delay of different wavelength are recorded by the oscilloscope. The experimental results show that group delay of 28ps is realized within the bandwidth of 20nm. In the end, the drift of the reflection spectrum and delay lines under different temperature are analyzed. The reflection spectrum drifts 0.1nm/°C and causes redshift of the corresponding delay line.

Citation Download Citation

Xu Wang, Shasha Liao, and Jianji Dong "Optical true time delay based on contradirectional couplers with single sidewall-modulated Bragg gratings", Proc. SPIE 10026, Real-time Photonic Measurements, Data Management, and Processing II, 100260C (4 November 2016); https://doi.org/10.1117/12.2247010

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

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.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available