Optical Feedback Cavity Phase Control for Multi-Wavelength Lasers
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Solution Overview
Problem
Current multi-wavelength lasers face challenges in controlling emission properties, particularly in balancing power between modes and tuning wavelengths independently, with existing solutions being complex, bulky, and prone to mechanical failures or requiring precise control of multiple amplifiers.
Innovation Solution
A photonic integrated circuit device with a lasing cavity and an optical feedback cavity, featuring a variable phase shifting element that allows for electronic control of phase shifts, enabling independent control of wavelength components without mechanical tuning or moving parts, and achieving robustness against environmental influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external forcing with wavelength selective optical feedback is used, then controlled multi-wavelength emission can be obtained, but the setup becomes complex and bulky requiring careful design, control and alignment
Solution Approach 1:
The patent combines multiple functions (wavelength selection, feedback control, and laser emission) into a single integrated device structure. The feedback cavity is directly coupled to the lasing cavity, eliminating the need for separate external forcing components and their associated alignment mechanisms.
Solution Approach 2:
The feedback cavity serves multiple functions simultaneously: it provides wavelength-selective feedback, acts as a resonant cavity for mode control, and enables power balance adjustment between different wavelengths through its coupling to the lasing cavity, replacing multiple separate control mechanisms.
2Ease of operation
If pivotable reflective diffraction grating is used for wavelength control, then frequency control is achieved, but manufacturing of moving parts becomes complex and costly
Solution Approach 1:
The patent replaces the mechanical pivotable diffraction grating system with a stationary feedback cavity that uses optical resonance and coupling mechanisms to achieve wavelength control. This eliminates moving parts while maintaining wavelength selection capability through the cavity's resonant properties.
3Adaptability or versatility
If multiple independent cavities with semiconductor optical amplifiers are used, then independent wavelength control is achieved, but the system becomes significantly bulkier and requires controlling one gain section per wavelength
Solution Approach 1:
The patent merges multiple wavelength control functions into a single feedback cavity that interacts with a unified lasing cavity. The feedback cavity's resonant modes naturally provide wavelength differentiation, eliminating the need for multiple physically separate cavities and amplifiers while maintaining independent control capability.
4Reliability
If built-in spectrally selective components are used, then robust multi-wavelength output is ensured, but emission properties can only be marginally changed through injection current or temperature variations
Solution Approach 1:
The patent introduces dynamic control capability by coupling the feedback cavity to the lasing cavity in a way that allows the system to adapt its emission properties. The interaction between the two cavities enables tuning of power balance and wavelength selection through operational parameters while maintaining the spectral selectivity provided by the feedback cavity's resonant modes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides efficient, compact, and simple control of multi-wavelength laser emission, allowing for precise tuning of wavelength components and reducing dynamical instabilities, with the ability to switch between wavelengths with high selectivity and robustness against environmental factors.
Implementation Method 1
an optical feedback cavity which comprises a variable phase shifting element adapted for receiving an input signal to control a phase shift of light propagating in the optical feedback cavity
Implementation Method 2
an optical feedback cavity which comprises a reflective element for reflecting light, at least partially, back into the lasing cavity (2) such as to form a resonant cavity
Implementation Method 3
a lasing cavity for resonating at a plurality of discrete wavelengths
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention pertains to a photonic integrated circuit device (1) comprising a lasing cavity (2) for resonating at a plurality of discrete wavelengths and an optical feedback cavity (3) operably coupled to the lasing cavity via a front surface (5) of the lasing cavity. The optical feedback cavity comprises a reflective element (4) for reflecting light, at least partially, back into the lasing cavity (2) to form a resonant Fabry-Perot cavity between the front surface (5) and the reflective element (4). The optical feedback cavity (3) comprises a variable phase shifting element (6) adapted for receiving an input signal (7) to control a phase shift of light propagating in the optical feedback cavity. Preferably, the amount of light entering the lasing cavity (2) from the optical feedback cavity (3) is low enough to avoid dynamic instability of the lasing cavity. The reduction in light is preferably obtained using an attenuator.