Micro-ring laser bandwidth enhancement with micro-ring resonator
Implementations disclosed herein provide semiconductor resonator based optical multiplexers that achieve enhanced bandwidth range of light emitted therefrom. The present disclosure integrates silicon devices into resonator structures, such as micro-ring resonators, that couples a side mode with a lasing mode and resonantly amplifies coupled light to output light having an enhanced bandwidth with respect to the lasing mode. In some examples, the optical multiplexers disclosed herein include a bus waveguide; a first resonator structure optically coupled to the bus waveguide and comprising an optical amplification mechanism that generates light and a single mode filter to force the generated light into single-mode operation; and a second resonator structure optically coupled to the first resonator structure and comprising a phase-tuning mechanism. The phase-tuning mechanism can be controlled to detune phase of light in the second resonator relative to the light in the first resonator.
1 . A method for multiplexing, the method comprising:
generating single-mode light in a first resonator structure, the first resonator structure comprising an optical amplification mechanism and a single mode filter;
modulating optical gain of the first resonator structure between a cold cavity condition and a second gain condition via the optical amplification mechanism to generate a side mode different from a lasing mode generated at the cold cavity condition that propagates in the first resonator structure;
detuning a second resonator structure relative to a phase of the single-mode light generated in the first resonator structure to one-half a cold cavity linewidth of the lasing mode, wherein the detuning aligns a phase of light propagating in the second resonator structure with the side mode generated at the second gain condition to resonantly amplify the side mode, the light propagating in the second resonator structure is received via optical coupling between the first and second resonator structures; and
outputting a bandwidth enhanced light onto a bus waveguide via optically coupling to the first resonator structure, the bandwidth enhanced light comprising the single-mode light from the first resonator structure and the amplified side mode.
2 . The method of claim 1 , further comprising applying a voltage bias to the optical amplification mechanism, wherein the optical amplification mechanism comprises one or more of quantum dots, quantum wells, and quantum-dashed structure that emit light responsive to the applied voltage bias.
3 . The method of claim 1 , further comprising:
coupling the side mode with the lasing mode to produce the bandwidth enhanced light based on the detuning of light propagating in a second resonator structure relative to a phase of the single-mode light generated in the first resonator structure to ne-half the cold cavity linewidth,
wherein the side mode is resonantly amplified in the second resonator structure.
4 . The method of claim 1 , wherein detuning a phase of light propagating in a second resonator structure relative to a phase of the single-mode light generated in the first resonator structure to one-half the cold cavity linewidth comprises controlling a phase-tuning mechanism, coupled to the second resonator structure, to tune a resonant frequency of the second resonator structure based on one or more of carrier injection, charge depletion, and changing temperature of at least a portion of the second resonator structure.
5 . The method of claim 1 , further comprising setting a quality factor (Q factor) of the first resonator structure to be approximately equal to a Q factor of the second resonator structure.
6 . The method of claim 1 , further comprising tuning a coupling coefficient of optical coupling between the first and second resonator structures.
7 . The method of claim 6 , wherein tuning the coupling coefficient comprises tuning the coupling coefficient to provide constructive interference between the side mode generated at the second gain condition and the light propagating in the second resonator.
8 . The method of claim 1 , wherein the second resonator structure is a passive structure that does not include any optical amplification mechanisms.
9 . The method of claim 1 , wherein the optical amplification mechanism is configured to generate light through self-seeding.
10 . The method of claim 1 , wherein the first and second resonator structures are micro-ring structures.
11 . The method of claim 1 , wherein the amplified side mode couples with the single-mode light in the first resonator structure based on the modulating of the optical gain to provide the bandwidth enhanced light, wherein the bandwidth enhanced light has a bandwidth that is wider than the cold cavity linewidth of the single-mode light.
12 . The method of claim 1 , wherein the optical amplification mechanism comprises:
a cathode formed on a waveguide of the first resonator structure;
a mesa structure formed on the cathode, the mesa structure comprising an optically active medium; and
an anode formed on the mesa structure,
wherein the optically active medium generates and emits light based on a bias applied between the cathode and the anode.
13 . The method of claim 4 , wherein the phase-tuning mechanism comprises a heterogeneous metal oxide semiconductor (MOS) capacitor.
14 . An optical multiplexer comprising:
a first resonator structure comprising an optical amplification mechanism and a single mode filter that generates single-mode light in the first resonator structure, wherein the optical amplification mechanism generates a side mode different from a lasing mode generated at a cold cavity condition that propagates in the first resonator structure by modulating optical gain of the first resonator structure between the cold cavity condition and a second gain condition;
a second resonator structure optically coupled to the first resonator structure, the second resonator structure comprising a phase-tuning mechanism that detunes the second resonator structure relative to a phase of the single-mode light generated in the first resonator structure to one-half a cold cavity linewidth of the lasing mode, wherein the detuning aligns a phase of light propagating in the second resonator structure with the side mode generated at the second gain condition to resonantly amplify the side mode, and wherein the light propagating in the second resonator structure is received via optical coupling between the first and second resonator structures; and
a bus waveguide optically coupled to the first resonator structure, wherein a bandwidth enhanced light is output onto the bus waveguide via optically coupling to the first resonator structure, wherein the bandwidth enhanced light comprises the single-mode light from the first resonator structure and the amplified side mode.
15 . The optical multiplexer of claim 14 , wherein the second resonator structure is a passive structure that does not include any optical amplification mechanisms.
16 . The optical multiplexer of claim 14 , wherein the optical amplification mechanism is configured to generate light through self-seeding.
17 . The optical multiplexer of claim 14 , wherein the first and second resonator structures are micro-ring structures.
18 . The optical multiplexer of claim 14 , wherein the optical amplification mechanism comprises:
a cathode formed on a waveguide of the first resonator structure;
a mesa structure formed on the cathode, the mesa structure comprising an optically active medium; and
an anode formed on the mesa structure,
wherein the optically active medium generates and emits light based on a bias applied between the cathode and the anode.
19 . The optical multiplexer of claim 14 , wherein the phase-tuning mechanism comprises a heterogeneous metal oxide semiconductor (MOS) capacitor.
20 . The optical multiplexer of claim 19 , wherein the MOS capacitor comprises:
a first semiconductor material layer comprising a first material formed in a waveguide of the second resonator structure;
a second semiconductor material layer formed in the waveguide and comprising a second material that is different from the first material; and
an interfacial oxide layer formed between the first semiconductor material layer and the second semiconductor material layer, wherein changes in carrier concentration occurs at the interfacial oxide layer based on a bias applied to the first and second semiconductor material layers, wherein the changes in carrier concentration induce a phase shift in the waveguide.