Reflective AWG with flattened response

A new principle for flattening AWG responses is demonstrated. The approach works in reflection, where the spectrum of the reflected light shows a box like shape, with only a small passband ripple. The method is in principle lossless. The main part of the device is formed by a general multimode intetference reflectoc This MIR works as a retro reflector that not only preserves the field shape, but also the position of the field. A pure propagation direction reversal is obtained in this wa~y The theory behind the principle is explained, and we present simulation results and initial measurement results

Optimized MMI coupler shape for reduced back-reflections

Spurious back-reflections can be a source of concern in photonic integrated circuits. This is especially true in circuits containing amplifiers, but even in passive circuits, small reflections can already have a strong influence on circuit performance. It is known that strong back-reflections can be present when using a 2×1 MMI as a combiner. We investigate methods for reducing these spurious reflections in a generic integration technology. We present a novel MMI shape which is able to reduce reflections by more than 20 dB

High-Resolution AWG-based fiber bragg grating interrogator

A novel InP-based monolithically integrated multiwavelength detector is used as the central part of a fiber Bragg grating interrogator unit. We have designed the arrayed waveguide grating (AWG) in the device such that at least two detectors have a significant signal at any wavelength being measured. Consequently, the measurement resolution is increased, while keeping the area of device small. We demonstrate the resolution of the measurement to be 0.32 pm over a working range of 10 nm. The corresponding relative resolution of 0.003% is to our knowledge the best reported to date in an integrated interrogator

New two-port multimode interference reflectors

Multi-mode interference reflectors (MIRs) are versatile components. Two new MIR designs with a fixed 50/50 reflection to transmission ratio are introduced. Measurements on these new devices and on devices similar to those in [1] are presented and compared to the design values. Measured losses are between 0.4 and 4.6dB. The measured power split ratio is in excellent agreement with the predicted split ratio of reflection and transmission

AWG-based integrated fiber-Bragg-grating interrogator with improved sensitivity

A Fiber Bragg Grating interrogator based on an AWG with custom design of the inputs is described. The proposed modifications ensure a non-zero readout signal on at least two detectors for any wavelength. It is shown that the combined readout allows to track wavelength changes with a resolution better than 5 pm

Amplitude and phase error correction algorithm for 3 x 3 MMI based Mach-Zehnder interferometers

Multimode Interference couplers (MMI) can have deviations in their amplitude and phase relations with respect to the ideal case. When using MMIs to construct a Mach-Zehnder interferometer (MZI), these deviations lead to non-ideal MZI behavior. In this paper, we introduce a correction algorithm that is able to strongly reduce amplitude and phase errors in 3 x 3 MMI based MZIs. Such MZIs are frequently used in phase estimation schemes in wavelength meters. Our method reduces the maximum phase estimation error to 2°, as measured in fabricated devices. This is two to three times better than the conventional method by Todd et al

Lossless wavelength selector based on monolithically integrated flat-top cyclic AWG and optical switch chain

We present an InP monolithically integrated wavelength selector that requires log2N switches for selecting N modulated wavelengths. Loss-less and nanosecond time-scale operation with 35dB OSNR and error-free dynamic wavelength selection of four modulated wavelengths with 2.6dB power penalty is demonstrated

Amplitude and phase error correction algorithm for 3 x 3 MMI based Mach-Zehnder interferometers

\u3cp\u3eMultimode Interference couplers (MMI) can have deviations in their amplitude and phase relations with respect to the ideal case. When using MMIs to construct a Mach-Zehnder interferometer (MZI), these deviations lead to non-ideal MZI behavior. In this paper, we introduce a correction algorithm that is able to strongly reduce amplitude and phase errors in 3 x 3 MMI based MZIs. Such MZIs are frequently used in phase estimation schemes in wavelength meters. Our method reduces the maximum phase estimation error to 2°, as measured in fabricated devices. This is two to three times better than the conventional method by Todd et al.\u3c/p\u3

Sidelobes caused by polarization rotation in arrayed waveguide gratings

Polarization rotation within an Arrayed Waveguide Grating (AWG) is found to cause sidelobes in the response of the AWG. The devices in which this effect was observed are briefly discussed. Their measured responses are compared to a detailed simulation